Climate Change: 'No Time to Lose' in Doing Exactly What?  (2006+)


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Background + Addenda

Background

In October 2006 the Climate Change Roundtable produced a report, Australia Responds: Helping our Neighbours Fight Climate Change, which drew upon earlier work by the CSIRO.  Both reports are available at http://www/ccdr.org.au. The CSIRO's report started with the assumption that climate change is attributable to greenhouse gas (GHG) emissions and then explored the economic / social / political impacts which would follow from that assumption. The Roundtable also explored options available to Australia to respond on the basis of the CSIRO's impact  analysis, and its theme was seen to be 'No Time to Lose'.

However it seems unclear exactly what there is 'no time to lose' in doing.

A useful account of the consensus emerging amongst scientists involved in the International Panel on Climate Change (IPCC) is John Houghton's Climate Change: The Science, The Impacts and the PoliticsA revised version of the IPCC's scientific assessment of climate change was made available in early 2007, and in late 2007 another revision suggested that GHG increases and associated climate effects were accelerating requiring urgent and significant cuts in GHG emissions to avoid possible abrupt or irreversible climatic changes with many serious consequences.

A useful overview of critiques of the official view is 'The Stern Review: A Dual Critique', a heavily-referenced document, of which an outline is reproduced below. A fairly light-weight argument is presented on the web-site of the makers of The Great Global Warming Swindle. Various web-sites are available which present counter-arguments (ie suggest ways of responding to any questioning of the IPCC's consensus) eg the RealClimate web-site, and New Scientist's Climate Change: a Guide for the Perplexed.

Wikipedia article on Global Warming provides a brief introduction to the complexities of the issues involved that seems more comprehensive than the IPCC's presentation (though the fact that when consulted by the present writer it was incomplete because of unresolved controversies amongst contributors gives perhaps the most relevant insight into the state of the debate) .

There seems little doubt that climatic change is occurring (though the possibility that observed changes could prove cyclical can't be entirely dismissed). Moreover it seems likely that a 'greenhouse effect' associated with human emissions of carbon dioxide (CO2) and other gases is (at least) part of the cause.

None-the-less, for various reasons the conclusions being drawn from this by the IPCC and its supporters seem overly simplistic.

Oversimplification?

 

Oversimplification?

The Science is Uncertain

Despite Al Gore's assertion (in An Inconvenient Truth) that none out of a sample of 928 technical papers disagreed with the basic science of global warming, it seems an inconvenient truth that only a very small percentage of climate scientists fully support the interpretation of the link between climate change and CO2 emissions that Gore assumed to be beyond discussion [1]. Accepting that humanity is affecting the climate and that CO2 and other greenhouse gas (GHG) emissions are part of the story is not the same as accepting that GHG emissions are all that really matters, and that the mechanisms involved are adequately understood.

An important issue seems to be the validity of the (so called) 'hockey stick' diagram. This diagram showed fairly constant temperatures for 1000 years before the 20th century with a dramatic rise then correlating with rising CO2 concentrations. It caused public alarm (eg when used ny Al Gore as a centre-piece of An Inconvenient Truth) [1]. However it apparently downplayed earlier, well documented, significant warmings and coolings - and was thus challenged professionally.

This issue is very important, because geological history is littered with examples of climate changes that are vastly greater than have been experienced recently, and the main basis for concern about current changes is that the rate of change may be exceptional (an assumption that would be falsified if it were shown that other climatic shifts have been equally or more rapid).

Unfortunately, the scientist who developed the 'hockey stick' diagram refused to release his 'private intellectual property' to those who wanted to check it (a check that was vital to establishing real scientific validity) so many years were reportedly needed to formally re-assess the diagram [1].

This seems not to be the end of the story because computer models used to correlate climatic change with greenhouse gas (GHG) levels have been built on the 'hockey stick' assumption (ie that there were no powerful influences causing global temperature changes in the centuries before the 20th century) [1]. Models may need to be redeveloped taking more account of natural drivers of climate change. If allowance has to be made for robust influences on the earth's climate by natural drivers, the perception that anthropogenic GHGs are the only significant driver of late 20th century climatic change would not necessarily survive.

Another important question apparently relates to the long term energy storage which seems possible in the earth's climatic systems (eg in oceans and in atmospheric circulation). The IPCC appears to have have assumed that reducing radiant energy escaping to space through a greenhouse effect will simply result in heating of the earth - whereas it seems likely that large amounts of energy can be stored without resulting in significant immediate temperature gains, and possible that recent warming reflects the release of energy stored in those systems hundreds of years ago (see further below). 

Other uncertainties (many of which appear to be the subject of active for-and-against disputes) can be illustrated as follows:

  • some scientists clearly acknowledge the uncertainties of climate models [1, 2, 3];
  • modelling has been used to try to deal with uncertainty - yet can't do so meaningfully [1];
  • the process of modelling the effect of GHG forcings allegedly involved a 'circular' (and thus invalid) argument. Originally models over-estimated warming by a factor of three - and this difference was eliminated by assuming an offset by aerosols. The latter's effects are not really known, and it was simply assumed that they must be sufficient to offset the over-estimate resulting from the GHG forcing [1]
  • it has been suggested that many declare the science of global warming settled, because they don't understand how science works. There is a lot of scope for better theories to emerge [1];
  • professional critique has been leveled at the IPCC's work [1]. For example observers have suggested that:
    • it was defective in relation to: under-estimating solar and natural greenhouse effects; ignoring earlier periods of higher temperatures in order to portray recent temperature rises as exceptional; overstating temperature rises; being inconsistent with a law of physics; and tripling the man-made greenhouse effect [1];
    • an IPCC insider has argued that IPCC does not attempt to forecast future climatic conditions - because its models are not initialized to anything like the currently observed climate [1]. [Another observer suggested that, despite this, IPCC's climate models have been confirmed as they model the past 100 years to a reasonable degree;[1]
    • it assumes that the earth's climate responds to GHG forcing by temperature rises causing more outward radiation to balance the extra incoming energy. However this is over simplistic as the climatic system involves massive energy stores and can potentially adjust to increased energy input for hundreds of years without significant temperature rises, eg in oceans and by changed circulation patterns. Climate change is real, but probably driven by variations in surface temperatures in the tropical oceans as a result of solar influences on the earth over hundreds of years. Recently observed warming can be 'forecast' by assuming that change is driven by tropical ocean temperatures (which the greenhouse effect can't affect in the short term) just relevantly as it can be 'forecast' by assuming that change is driven by increasing GHG levels - and there are reasons to prefer the former theory [1];
    •  it ignored past warm periods and the  saturation effect which limits the heating effect of increasing CO2 concentrations; sunspot activity suggests that the 1976-2000 warming trend is ending; CO2 emissions only correlate with warming from 1976 to 2000; claims that the science is settled and the debate is over are false; there is no evidence that CO2 emissions cause the weather effects blamed on them; and 'tropical' diseases are mainly a product of poverty and poor sanitation; [1] ;
    • current IPCC models assume that the earth's albedo is constant, though evidence exist of changes in albedo due to unexplained changes in cloud formation - and thus greater absorption of radiation (10 times greater than that associated with greenhouse gases). Greenhouse gases may account for only 2-3% of warming [1];
    • all IPCC's models are interdependent - and all seem to get clouds wrong - which has a huge impact [1
    • doubling of CO2 concentrations are claimed likely to lead to a 1 degree C temperature rise, because it is assumed that their effect is reinforced by water vapour (whose behaviour is not actually known). Alternative reasonable assumptions suggest only a 0.5 degree temperature increase [1];
    • water vapour concentrations seem actually to be declining since 1948 as CO2 concentrations have risen [1] - and, given the large greenhouse impact of water vapour, this (presumably) may indicate a natural balancing effect to stabilize the earth's temperature
    • IPCC claimed that the link between forcings and temperature gain involved a lambda value of 0.5 C / watt - though this value is known from Stephan Boltzman law (about 0.22-0.3 C / watt). The bigger lambda is assumed to be the more temperature gain is predicted by a given forcing. IPCC computer models use 1 C / watt, while Stern implies 1.8. GHG forcing in 20th century was 2 watts - which when multiplied by correct lambda yields observed temperature gains. Those using higher values fudge the model - by assuming oceans act a heat sink (though deep ocean temperatures have not changed or have been cooling). [1]
    • IPCC showed the medieval warm period on a 1996 graph, but selective use of data caused it to disappear by 2001 leaving a 'hockey stick' effect. [1]
    • there is a big difference between emission levels and increasing atmospheric concentrations - as most emissions are re-absorbed in various ways. IPCC predicts that methane levels in the atmosphere are increasing because emissions are increasing (and Stern review develops alarmist theories about acceleration in this trend) despite the fact that measurements show that actual methane levels are falling [1;]
  • major scientific papers have claimed, that: the forcing of methane has been 50% underestimated; half 20th century warming might be due to solar changes; cosmic rays could have a large effect on climate; aerosols are more important than greenhouse gases; and heat exchange in the oceans might fully account for the small 20th century temperature changes [1]. Other plausible suggestions in professional literature are that: local heating caused by urbanization and industrialization correlates with temperature trends; GHG forcings are likely to have minimal impact as global warming years is just a short episode in the geologic history - most likely due to increased solar and tectonic activities; cooling is likely early in the twenty-first century as solar activity decreases. [1]
  • there is little evidence of looming catastrophe or that human activity is to blame (eg data doesn't match alarmist theories; long term predictions are impossible; and history shows that natural climatic changes can be very large) [1];
  • global temperatures are paying little attention to the theory about their relationship with GHGs. Global surface temperatures peaked in 1998 and, after falling back a little, have stabilized though GHG levels continue to increase. One set of data show temperatures in the southern hemisphere going down [1];
  • climate change is understood to be occurring faster than predicted by models developed by the IPCC [1] - which highlights the limitations of the models.
    • [The IPCC's 2007 analysis suggested that models were now becoming more accurate in 'predicting' the past - though if this is achieved by inserting 'fudge factors' to achieve this outcome (as some critics have alleged) rather than building models off physical laws, then this does not guarantee future reliability of those models];
  • a large number of factors are now contributing to climate change [1]. Thus even if CO2 emissions were a trigger for change it may no longer be the only issue that needs consideration;
  • CO2 emissions have been suggested to account for only 26.5% of climate change (as compared with the IPCC's estimate of 48%) because numerous other factors have allegedly been downplayed, such as (a) ozone (b) methane emissions (c) albedo effect of soot on ice and snow (d) various aerosol effects and (e) solar effects [1].
    • [IPCC's February 2007 analysis suggested that while carbon emissions accounted for just over half (ie 55%) of the positive forcings (ie those contributing to global warming), methane, nitrous oxide and ozone were individually non-trivial positive forcings, and collectively have an influence (45%) not much below carbon. Moreover there are negative forcings (eg from aerosols) of a similar magnitude to the non-CO2 greenhouse gases]. 
  • evidence appears to exist of significant reduction in solar energy reaching the earth - the global dimming phenomenon - because energy is reflected by aerosol pollution (which create some of the negative forcings IPCC identifies as roughly equal to the positive forcings associated with carbon emissions). Reducing the use of fuels that generate carbon emissions will also presumably reduce global dimming - ie reducing fossil fuel use seems likely to have both a positive and negative effect on forcings;
  • students of long term climatic history (to which the IPCC seems to have paid limited attention in its analyses) have suggested alternative theories, for example  [1]; that
    • global temperature changes correlate with sunspot activity more strongly than with CO2 increases, and that sunspot activity (though not directly linked with significant changes in solar energy output) does substantially reduce cosmic radiation, which in turn is associated with reduced cloud cover and significantly increased warming;
    • while greenhouse gases have an important impact on the earth's climate, water vapour (which comprises 98% of all greenhouse gases) is the only one with any significant effect. An El Nino event in 1997 significantly increased atmospheric water vapour, and preceded the record temperatures of the next few years;
    • over the past 500 million years CO2 levels have been up to 16 times greater than at present, and the peak occurred at the coldest stage of a major ice age. Over the past 400,000 years CO2 levels have correlated with temperature changes, but CO2 rises came about 800 years after temperature increases [1] - apparently due to changes in biological activity. [Data suggesting much higher past CO2 levels are in 'The geological Record and Climate Change];
    • IPCC implies that CO2 ended the last 4 ice ages - but data shows that temperature changes preceded the CO2 increases [1].
  • the earth has self-stabilizing (ie homeostatic) mechanisms which amongst other things reduce GHG levels [1]. For example:
    • oxygen reacts with methane to produce CO2 and water - and both could not be present together in the atmosphere unless there was a constant supply of each - which can be attributed to living organisms;
    • living organisms also reduce CO2 levels. CO2 concentrations on Mars and Venus are 95% of the atmosphere (and there is virtually no oxygen or methane). The earth's atmosphere was similar around 4bn years ago with a much stronger greenhouse effect. Also the sun was cooler than at present. Living organisms reduced CO2 concentrations as the sun grew hotter (maintaining a stable global temperature) by using CO2 and water to produce carbohydrates and oxygen in the process of photosynthesis. The chalky shells and skeletons of those organisms (incorporating calcium carbonate) produced vast natural CO2 dumps (eg in the Great Barrier Reef and the White Cliffs of Dover);
    • the chalky shells of blooms of microscopic plants (coccolithorid algae) can be seen on satellite images to turn large areas of the oceans milky white as they reduce CO2 levels to stabilize the earth's temperature.
    • plants tend to increase their growth when there is more CO2 in the atmosphere
  • late 20th century warming trends are similar to earlier events [1];
  • in some places it was hotter  in Bronze Age and Roman times. This was caused by the sun - whose effect as a 'forcing' the IPCC only counts from 1750. Also the effect of CO2 forcings  is doubled by assuming climate feedbacks, where this is not done for solar forcings. Recent solar changes have been large. Over the past 50 years the sun has been warmer than for 11,000 years. IPCC estimates the sun's forcing as 0.3 watts since 1750. But if started from 1900 (to match the temperature start date) the sun's effect could be 1.9 watts - enough to account for all 20th century warming [1];
  • 20th century changes in CO2 levels do not correlate well with temperature changes - despite claims that this is the most important factor. Temperatures rose in the first half of the century before major increases in industrial emissions occurred, and then fell from 1945 to 1965 while industrial emissions grew rapidly [1];
  • balloon and climate data are the only truly global sources of comparable temperature data. Balloon data shows that a lot of the late 20th century temperature increase occurred in single step in 1976-1977, while satellite data shows little increase after 1979;
  • some experts have seen a need to substantially upgrade satellite observation systems to make reliable basic data about climate change available ("Satellite Observation of the Climate System: The Committee on Earth Observation Satellites (CEOS) Response to the Global Climate Observing System (GCOS) Implementation Plan (IP)");
  • the earth's climatic history has featured several ice ages in the past 70m years of which the 'current' ice age (starting 3m years ago) has involved about 20 glacial advances and retreats - the most recent retreat starting around 20,000 years ago. The significant cooling and subsequent warming associated with these suggests that there are mechanisms for global warming (and cooling) that are unrelated to human carbon emissions. One account of the process of glacial advance (and of the 'current' ice age) suggests that:
    • long term climatic changes are driven by: solar output; distance between the earth and the sun; the position of continents; ocean circulation; and atmospheric composition;  and that
    • atmospheric CO2 is one of the factors involved, and is believed to vary with: metamorphic degassing; weathering of organic carbon; weathering of silicates (which reduces CO2); and the burial of organic carbon.
  • The IPCC assumes that the Earth was in a steady state until 250 years ago, which was upset by use of carbon fuels - but this never existed. The earth's climate has been affected by its environment (eg dust clouds) leading to ice ages. It has been both hotter and colder that at present in last 1500 years. The Sun is the main influence on climate, a fact not recognised by IPCC.  Natural global warming increases atmospheric carbon dioxide because in its solubility in sea water falls with increasing temperatures. Sea level rises are due to use of non-rechargeable groundwater. Air pollution is only a local issue [1]
  • in the 1970s there was a scientific consensus that there was a dangers of a different type of climate change - a new glacial advance in the 'current' ice age. A businessman suggested in 2007 that burning more coal to ward off that risk was just as sensible as cutting carbon emissions [1];
  • climate change is the outcome of cycles in the sun's electro-magnetic radiation which correlate with sun-spot cycles and interact with earth's magnetic fields. CO2 is not significant - plants and animals absorb / emit it. And oceans absorb or release it depending on temperature [1]
  • A New Theory of Climate Change suggests that the effects of greenhouse gases are less than has been assumed - and solar variations (which affect cosmic rays and thus cloud formation) may provide an hypothesis that better matches observations [1] - a view that has critics;
  • Great Global Warming Swindle outlines the views of scientists who believe that global temperature changes are driven by solar activity, not greenhouse gases. [1, 2];
  • concerns have been expressed about Al Gore's campaign against global warming (An Inconvenient Truth) claiming it contained inaccuracies, and did not point out that current phenomena fall within a natural range [1];
  • climatologists are said to realize that water vapour dominates global greenhouse effects - and that the effect of gases released by human activity is virtually insignificant - though water vapour is conventionally ignored by those seeking to identify human contributions to greenhouse effects (see Water vapour rules the Greenhouse system). Others suggest that water vapour is correctly ignored because it only persists for a short time in the atmosphere - and its concentration is determined by other factors (see Water Vapour: Feedback or Forcing);
    • [An aside: surely, if water vapour is the 'elephant' in the greenhouse room and its behaviour is determined by other factors, then there has to be a huge amount of effort to make sure that those other factors are well understood, and that none are neglected. The IPCC does not seen to have done this].
    • water vapour in the atmosphere increases as ocean surface temperatures increase - especially when those temperatures exceed 27 degrees centigrade [1]. Moreover, as noted above, ocean surface temperatures have increased; correlate well with 20th century global warming; but aren't just a consequence of recent greenhouse effects;
  • polar ice caps have reportedly been observed to be melting on Mars - suggesting that whatever is happening is not solely of terrestrial origin [1]. Mars has warmed 0.65 degrees centigrade over the past 50 years (compared with the earth's 0.6 degrees) according to a Nature article [1]. Warming on Mars since 1970 is comparable to that on earth over the same period [1];;
  • there seems to be evidence of climate change on Jupiter [1]
  • the Antarctic has cooled and gained ice mass over the past 30 years - reversing a 6000 year trend [1] - a suggestion that others have disputed [1]. There was seen to be a risk that large scale loss of ice from Antarctica could significantly raise sea levels if a 'tipping point' is reached, but no certainty about when that might occur. [1];
  • global warming is not the only potential cause of climate change. For example:
    • 2007 drought conditions in Australia apparently reflect a southward shift in weather patterns (eg rain that would have fallen over Australia is now falling over the Southern Ocean). This seems compatible with Solomon's observations that the rapid cooling of the atmosphere above the Antarctic (as a result of ozone depletion) has apparently caused atmospheric circulation patterns around the South Pole to narrow towards the Pole - and other circulation patterns to shift southward [1]. The hole in ozone layer over Antarctica is the largest ever though CFC levels peaked in 2000 - as they have become more effective in destroying ozone as temperature has fallen  [1]
    • the 3.2km thick ice in the Amundsen Sea Embayment in Antarctica is thinning - and this could cause oceans to rise significantly. This seems to be due to wind changes that cause warmer waters to flow beneath ice shelves - perhaps due to global warming or to ozone depletion [1];
  • some observers claim that there is a 'law of diminishing returns' in relation to the greenhouse effect of rising CO2 levels [1] - with 60% of the maximum warming effect being achieved by concentrations of 50ppm - and a quite negligible increase in greenhouse effect from even a doubling of current CO2 levels and probable greater warming effects coming from other sources (eg water vapour) [1]. The forcing effect of CO2 varies with logarithmically with its concentration [1]. These conclusions appear to result from work at the University of Chicago'a MODTRANS Centre - and was recorded in "Climate Outlook to 2030" (Archibald D) [1]
  • it seems odd to assume that Pacific Islands are now likely to be flooded by rising sea levels [1] - as those islands have been exposed to huge rises in sea levels over the past 15000 years as continental glaciation retreated and the coral polyps that build many of them have apparently managed to keep their heads at water level. The assumption that islands will be submerged because coral can no longer grow due to higher temperatures is also an assumption that reefs will not adapt to changed conditions as they have undoubtedly done in the past;
  • the science of climate modeling is subject to vast uncertainties - as indicated by the general inability of weather forecasters to look far into the future. Though the systems involved are not identical, and forecasting has been improving, this constraint should not be ignored. Given the complexity of the systems involved almost any claim to have identified the 'true science' is likely to be out of date in 5 years;
  • in 2015 the British Meteorological Office drew attention to the possibility of another little ice age in parts of the north hemisphere by the 2030s because a rapid decline in energy emissions from the sun could create a situation like the 1645-1715 Maunder Minimum. The effect would depend on the extent of global warming associated with the IPCCs scenarios and would be limited as far as earth as a whole was concerned [1, 2];
  • a former Australian Greenhouse Office climate modeler has suggested that there are errors in the architecture of the IPCC's basic climate model that underpins all climate science. While the model reflects valid physics the way it is applied over-estimates the effect of CO2 by 5-10 times. This suggests that CO2 has caused less than 20% of global warming in recent decades and explains why climate models have been unable to explain the pause in warming that has been observed over the past 18 years [1
  • the world has experienced an 18 year pause in the warming that climate change models predict. In the lead up to the Paris Climate Change conference, there was a need to explain this - so it has been claimed that heat has been absorbed in the oceans. The problem is that scientifically literate critics quickly found problems in this explanation (eg its incompatibility with satellite observations).  However this has been kept from mainstream media. The problem is that the man in the street already suspects that data has been manipulated to conform with climate model predictions of warming [1 - by a former Chief Research Scientist of the CSIRO Division of Atmospheric Research].
  • in early 2016 it was simultaneously suggested that:
    • 2015 was the earth's hottest year on record according to US NOAA and UK Met office - with temperatures averaging 0.9C above 20th century average of 13.9C. And the previous record was broken in 2014. There is compelling evidence that the so called global warming hiatus is over [1];
    • the geological record shows (according to Professor Bob Carter) that climate always changes. In the Younger Dryas period (14,5000 years ago) some have suggested that temperatures rose 10C in a decade. Change may not be that extreme but current rates of change (ie less than 2C per century) are anything but unusual. Also modern temperatures are not unusual in geological history. The more CO2 is added to the atmosphere by industrial processes, the less effective it becomes in raising temperatures. However it does help green the planet and boost agricultural yields [1]
  • in early 2016 a proposal was announced to end the CSIRO's emphasis on understanding climate change - and to rather emphasize research into practical measures to deal with it. This was based on the view that climate change had already been well modeled. This triggered outrage amongst top scientists who did not believe that the climate change problem had been solved [1]
  • changes to CSIRO coincide with critique of climate models by John Christy (a professor of atmospheric science) in US. Climate models have predicted much greater climate change over the past 20 years than actually occurred. Dominant assumptions about CO2 as the driver of change must be wrong. CO2 is a greenhouse gas - but many other factors clearly need to be taken into account [1]
  • studies of changes to Antarctic ice show that Australia's assumptions about the high and low extremes of rainfall that the continent experiences are much too low [1]
  • satellite studies show that the way clouds are distributed over the earth has changed over the past few decades. Cloud coverage has shifted towards the poles - thus expanding the sub-tropical dry zones. Clouds tops are also stretching higher into the atmosphere. These changes can contribute to global warming [1] [CPDS Comment: it is, of course difficult to know what has caused changes to cloud patterns. It could be a result of climate change, though it is noted that cooling effect of the hole in the ozone layer over the Antarctic has been suggested to have drawn the atmospheric circulation patterns towards the pole]
  • The Antarctic peninsular which has been regarded as a global warming 'hot spot' has been cooling for almost 20 years. Natural variability has been suggested to account for both warming since the 1950s and cooling more recently. Though peninsular cooling started at the same time as the 'global warming hiatus' (ie 1998) what happened in Antarctica is believed to be unrelated [1]
  • NASA released research suggesting that global historical temperature data needed wholesale revision. Based on proxy indicators where actual temperature records did not exist suggested that temperatures have been rising since the start of the industrial revolution. Previous data had missed about 20% of early warming. This adds to debate about whether models or field observations are better at revealing climate change. Previously sophisticated models had made temperature changes seem larger than otherwise imagined - by filling in blank spaces in observations. A recent analysis of early ocean temperature records had made so-called pause in surface temperatures disappear - though such a pause in now generally accepted and explained in terms of natural ocean cycles. However another recent study has suggested that temperature changes started at almost the same time as the industrial revolution [1]
  • atmospheric CO2 levels have reached record levels (over 400 ppm globally for a whole year). The level has risen because of El Nino weather phenomenon which has resulted in droughts that reduced the ability of oceans, forests and vegetation to absorb CO2 [11]

In response to claims about uncertainties such as outlined above, various web-sites provide defence of anthropogenic global warming theories on climate change [eg 1, 2]. One site maintained by the World Wildlife Fund  addresses challenges such as:

  • uncertainty - arguing that while future adjustments to theories will probably be required, they are unlikely to alter core conclusions;
  • 'hockey stick' - arguing that though significant warming and cooling may actually have occurred, late 20th century warming is without recent precedent;
  • warming on mars - arguing that evidence on this is limited, and would imply that solar changes were the key factor;
  • solar effects - arguing that satellite measurements show little variation in solar outputs;
  • water vapour - arguing that its concentration varies with temperature - so it needs to be treated as a feedback, rather than as a forcing;

By early 2010, the certainty of climate science seemed to have been severely reduced as a result of diverse challenges (eg lack of significant evidence of warming since 1995, dubious sources of some claims, and distortion of the scientific process) [1]

Bias is Possible

There are widespread allegations of distortion of public debate and behind the scenes political influence by 'deniers' orchestrated by fossil fuel interests [1, 2, 3, 4].

On the other hand the IPCC's conclusions are increasingly being treated by the public (and thus by politicians) as 'gospel' though:

  • every aspect of debate which is claimed to be settled is subject to fierce debate [1, 2];
  • the IPCC was established in1988 (after a climatologist had plausibly predicted large temperature and sea level rises that didn't actually happen [1]) to investigate only on the effect of human-induced climatic change [1]. Moreover:

    • its 2007 February analysis presents a refinement of that Panel's 'consensus' theory about climate change, whilst not mentioning alternative theories - and thus, even if its theory is correct, the IPCC erodes its own credibility by leaving many questions unanswered. Two points can be considered in relation to this:

      • one-eyed behaviour is characteristic of politicised organisations. Where a particular answer is politically favoured, Daniel Ellsberg's analysis of the Pentagon showed that selective staffing and evaluation of evidence can result in that conclusion emerging [1];

      • there is also a recognised weakness in the scientific method related to the 'theory-dependence of observations' (ie people tend to perceive only what they expect to see) (see Chalmers A and F, What is this thing called science?, Uni of Qld press, 1996)

    • 20 years ago climate research became politicised in favour of one hypothesis - based on study of greenhouse gases. Those following different theories encountered impediments to their careers. It was only in 2005 that funding could be obtained to conduct research on an alternative plausible hypothesis [1];

    • the global warming scare has been described as scientific fraud [1];

    • there is seen to be: a highly political process to produce IPCC reports; a lack of seriousness about its February 2007 assessment report where the executive summary was published weeks before the report itself - so that the latter could be edited for consistency; an increasing tendency to stifle debate and intolerance of dissenting voices; and outrage that the science is said to be settled [1];
    • it has been suggested that UN Council's generally tend to be politicised and its 'expert' bodies to be democratically illegitimate [1];
    • many scientists support IPCC trusting that it will do the right thing. But this faith may be misplaced as IPCC has been biased. It has never commented on the discrediting of the hockey-stick diagram on which it originally placed great weight or announced any review of its processes as a result [1];
    • it may have been a big mistake for governments to have exclusive reliance, in matters of great complexity, on a single source of analysis of the implications of climate change (ie the IPCC) [1].
  • Global Warming: Forecasts by Scientists versus Scientific Forecasts suggests that IPCC forecasts are not based on scientific procedures - but are merely the opinions of scientists. Exerts are often wrong.   IPCC approach of fitting models to historical data and then claiming that they are suitable for forecasts in not a sound way of forecasting. [1];
  • analyses and datasets are relied upon that are not accessible for review - which is contrary to basic requirements of scientific process. Claims are made that theories have not been falsified, when it is impossible to do so without access to to the data and computer programs involved. Governments do not insist on proper disclosure - despite the 'hockey stick' scandal [1]. Similarly governments assume that peer review (which is only intended to ensure reasonable quality in journal articles) guarantees that theories are correct - even though peer review groups are inbred [1]
  • while the 'consensus' method used to develop the IPCC's conclusion on the science of climate change is potentially powerful, it does not guarantee truth (ie a 'flat earth' and the 'Y2K crisis' were once established consensus views; and science is characterised by periodic 'paradigm shifts' under which earlier consensuses are overturned). Moreover one scientist suggested that consensus was inappropriate in dealing with science issues [1], as evidence should settle such matters;

  • the climate scientists associated with IPCC are probably not a balanced group, because IPCC's mission was to limited to examining the possibility that human action was influencing the climate - so presumably a dominant majority of those involved would have a research interest in, and career dependence on, that theory;

  • professional critique has been levelled at the IPCC's work (see above) ;

Perhaps the strongest indication of possible bias by the IPCC is its persistent reluctance to address the possibility of very large changes in sea levels. Raising such risks might be avoided so as not to seem alarmist. However very large sea level changes have occurred in the recent geological past - and these events show that non anthropogenic factors (which are complex and by no means understood) can have a major impact on the earth's climate, and thus have to be considered (together with GHG effects) as drivers of current climatic change.

The IPCC's methods have long appeared technically inadequate to the present writer because the impact of global warming on sea levels was presumed to be linear and related mainly to differential expansion of water relative to the earth (eg a <1m rise in sea levels was forecast to result from a 2-3 degree Celsius rise in global mean temperatures - whereas climatic history is understood to suggest that sea level changes can be much larger (ie tens of metres) and occur quite quickly - presumably because feedback affects emerge as changes occur in ocean currents or atmospheric circulation patterns which alter the way heat is distributed globally and thus the amount of water locked up as ice. The Biblical account of the 'great flood' (which is shared by many peoples worldwide and presumably refers to the 100m or so rise in sea levels that followed the ending of the last ice age) suggested that  water covered the 'whole earth' as a result of something that happened over a short period (eg sudden collapse of the then North American ice sheet - a type of collapse which is now suspected to be possible [1])

  • [IPCC's February 2007 analysis suggested that:
    • sea levels had been 4-6m higher than at present during the last inter-glacial period 125,000 years ago;
    • there were possible feedback effects (eg related to release of CO2 from oceans) that could increase warming which (a) made it difficult to estimate the amount of CO2 emission reduction needed to achieve stability and (b) created uncertainty about the extent of sea level rises;
    • dynamic processes associated with ice flow (which could also increase potential sea level rises) might have an effect, but this was not taken into account in forecasts because it was too hard to estimate;
    • modest sea level rises over the next century (<1m) were likely associated with thermal expansion and some ice melting - a conclusion that ignored the (uncertain) effect of feedbacks;
    • a 7m rise in sea levels might occur before 2200 if the Greenland ice sheet were to disappear;
  • however its analysis made no obvious mention of the very large (100m) fall and (apparently sudden) subsequent rise in sea levels associated with the latest glacial advance and retreat of the current ice age;
  • but a mid 2007 IPCC report may warn that it may no longer be possible to prevent severe sea level rises (eg 4-6m) [1]

Moreover avoiding long term climatic history also downplays the fact that CO2 is not simply a potential cause of global warming. Its atmospheric concentration is apparently increased by warming as a result of reducing / reversing natural processes which absorb it (see Greenhouse Gases and Climatic History). From the point of view of the analysis reviewed in the latter document, this raises the possibility of dangerous feedback effects from anthropogenic GHG emissions. However, if non GHG climate drivers are significant, then it is possible that CO2 levels may be more an indicator of climate change than a primary cause.

Likewise the Stern review of climate change (which primarily explored the economic consequences of assuming that the IPCC's conclusions were valid) has been described as:

  • overly simplistic and perhaps counter-productive [1];

  • based on unrealistic assumptions that maximize the estimated damage from climate change and the need for immediate (rather than deferred) responses [1];

  • a biased exercise in speculative alarmism [1];
  • not really being a serious economic analysis [1];
  • professionally inadequate. It is: hard to assess as its analysis is unclear; an unbalanced view of policy options as it over-estimates projected benefits and under-estimates costs; poor in discounting the future; biased to radical immediate actions - without facing up to associated problems; plagued by omissions; weak in its use of data and sources [1];
  • alarmist as its picture of the situation is neither accurate nor objective. It understates the uncertainty about the evolution of poorly understood complex systems. Its treatment of sources and evidence is selective and biased. [1] Future population scenarios are unrealistically high, which distorts both expected emissions and their effects. Human adaptation and technological advances are not considered [1].

In 2010 a committee of scientists concluded that the IPCC "assigned high confidence to statements for which there is very little evidence, has failed to enforce its own guidelines, has been guilty of too little transparency, has ignored critical review comments and has had no policies on conflict of interest". Claims of using only peer reviewed data have been found to be unreliable. Counter theories have been unreasonably ignored.  All errors have the effect of exaggerating the likely effect of climate change. IPCC reports have been 'sexed up' in terms of policy implications - in ways that suited environmental lobbyists but discomforted scientists. While having believed three years ago that IPCC process was fair, this no longer seems valid [1]. The IPCC was suggested to have been told to focus on the science, rather than on the policy implications [1]

Subsequently Britain's Royal Society (the UK's top scientific authority) suggested that there were gaps in understanding that make predictions of the extent of climate change and sea level rises impossible. This can be seen as as a retreat from politics, following scandals that engulfed the IPCC. Society does not dismiss climate change or the need for coordinated action, but undercuts claims about looming ecological disaster.  [1]

'Business as Usual' Solutions may not Exist

It has reportedly been suggested (by Price Waterhouse Coopers) that a 30% cut in emissions could be achieved while saving money - because there are many low-cost emission reduction options available [1].

The World in 2050: Impact of Global Growth on Carbon Emissions and Climate Change Policy (PwC), which is basically an econometric analysis, identifies a Green Growth + Carbon Capture Scenario which allows a reduction in global CO2 emissions which would stabilize CO2 concentrations at around 450ppm. It involves (a) more nuclear and renewable energy sources (b) faster energy improvements and (c) carbon capture and storage. It cites sources which sources which suggest (a) the existence of technologies that would allow carbon emissions to be reduced and improve carbon capture and storage (b) the potential of increased carbon trading (c) that costs of reducing carbon emissions by 50-70% would be only 4-5% of global GDP - about a years growth (d) considerable benefits in learning by doing. Technological options suggested include (a) doubling car fuel efficiency (b) halving car usage (c) 25% more energy efficient buildings (d) 50% more efficient coal fired power stations (e) using gas for electric power (f) doubling nuclear power (g) 50 times current wind power (h) 700 times current solar power (i) use of hydrogen fuel cells (j) 50 times current biofuel production

Similarly McKinseys argued, based on analysis of 100 opportunities to reduce emissions and their associated costs, that 30% GHG reductions by 2020 (and 60% by 2030) would have only modest costs. Moreover 25% of total reductions would have cost benefits (eg better lighting and insulation) though others (wind power, geothermal options and reafforestation) would increase costs [1]

An Australian Climate Action Network (CANA) also presented a case for actions which might significantly reduce CO2 emissions. 

For example, in Turning Down the Heat: A Climate Change Action Agenda for Australia, CANA suggests that (a) significant reductions could be achieved by: changing the way things are done / efficiency standards / lifestyles (b) renewable energy would create new jobs / better public transport and reduce air pollution (c) demonstrating that renewable energy can provide base load power - by use of multiple sources and storage technologies, and use of hydrogen as a fuel (which can be achieved faster than nuclear power and 'clean coal') (d) pricing greenhouse gas pollution (e) removing subsidies on fossil fuel (eg discount pricing for bulk users) - and avoiding subsidies on nuclear energy (f) providing start-up subsidies for renewable energy.

The latter effort unfortunately contains factual distortions in order to imply that essentially all effort in reducing greenhouse emissions should focus on CO2 (presumably because this is something people can get to grips with) even though CO2 accounts for little more than half of the human-induced greenhouse effect (according to IPCC) and considerably less than half of human-induced radiative forcings according to other estimates [1]. CANA's analysis (Section 2.1)  suggested that (a) CO2 is the main greenhouse gas (b) mentions only some of the other human-caused greenhouse gases and (c) implies that aerosols merely cancel the effects of non-CO2 greenhouse gases.

However, even if it is assumed that CO2 and other GHG emissions are the only significant cause of climate change, it is not necessarily a trivial matter to reduce emissions. For  example:

  • a UN report suggests that it is too late to cut emissions to levels that would produce only a safe 2 degree centigrade rise in global temperatures. Emissions should already have peaked - but instead are rising rapidly, driven by growth in developing nations. [1]

  • It has been suggested that emissions might be stabilized by: development of nuclear energy; increased energy efficiency; CO2 capture; and renewable energy [1, 2]. However, all those options have limitations:
    • Nuclear energy is not an environmentally problem-free option, though this might change if fusion or thorium prove viable. Nuclear power also requires access to water which will tend to favour sites near cities that are still available because they are of high conservation value. Sites would also presumably need to be at least 10-20m above sea levels, if rising sea levels are one of the fears prompting such developments; 

    • Efficiency is a good idea but hardly novel;

    • CO2 capture would greatly reduce energy efficiency;

    • Renewable (ie ultimately-solar) sources are less 'concentrated' than fossil energy sources and are thus likely to be much less 'profitable' to develop - both economically and energetically - though some see light at the end of the end of this tunnel [1]. Also determined attempts by autocratic government to replace fossil fuel use in vehicles in Brazil appeared to generate adverse side effects, and to have only a marginal impact on overall oil consumption  [1];

  • practical alternatives to fossil fuels must involve 'high grade' energy sources - ie those which make a lot of energy available for use with little effort (and thus cheaply). There is no shortage of energy in nature - but there are shortages of energy that is readily / cheaply available for use. If very low-grade energy sources were all that were available (ie those where the energy available for use is only (say) 2-3 times the energy that must be expended in obtaining it which could apply to some renewable energy sources (eg bio-fuels) - as compared with the 10-50 times that can be available from fossil fuels) then the energy consumption / unit of GDP would increase dramatically and it may be physically impossible to produce enough non-fossil fuels to satisfy human demands - or so costly that this becomes economically disruptive;

    • [One observer suggested (personal communication) that a solar parabolic thermal dish system could have a lifetime Energy Return on Energy Invested (ERoEI) ratio of 50, and that favourable wind power sites could produce an ERoEI of 80. It was also argued that the ERoEI for oil now tends to be around 8, and is declining as the quality of resources being developed fall]

  • McKinsey's analysis [1] and similar work suggest combining many modest conservation and technological initiatives to produce large reductions in GHG emissions - a view about which caution has been suggested [1]. McKinsey's conclusion appears to be based on a literature study (ie a synthesis of other reports) without critically evaluating those sources. For example, biofuels are cited as as one contribution to GHG abatement with positive cost benefits (p14-15) - though other sources suggest that the priority (and subsidies) now devoted to producing biofuels in many countries could result in famine in vulnerable regions in the near future [1], while yet others note the effect that biofuel production has on inflation by boosting food prices;
  • various observers have questioned the feasibility and cost of reducing CO2 emissions:

    • there is a great deal of rhetoric about climate change - but the problem is that there is no solution. The IEA did an audit of 1400 policies to reduce fossil fuel use, and found that global emissions might at best only rise 30% by 2030 instead of 55%. To have any significant effect caps on carbon emissions would have to be set so low as to shut down the economy [1];

    • decarbonisation of the world’s economy would cause huge economic dislocation [1] ;

    • the public is being misled about the cost of reducing carbon emissions, as these costs will be very high and may not come smoothly; [1];
    • the Productivity Commission has argued that Australia will gain no immediate environmental benefit from greenhouse gas reductions - but could face large costs [1];
    • there has been discussion in Europe of adopting a target of 60% reduction in carbon emissions by 2050. An intermediate target (ie a 20% reduction by 2020) has also been suggested. However no one knows how this could be achieved, or the costs of doing so [1];
    • clean coal technologies would involve much higher costs for electricity generation [1];
    • to replace 10% of world's energy sources with non-carbon energy sources by 2020 would require 1000 new nuclear power stations [1];
    • electricity costs would increase 75% under IPCC proposals [1];
    • the world economy would have to be transformed to achieve major gains. Estimates of the cost of reducing emissions often assume 100% increase in energy efficiency. Also little attention is paid to non-energy GHGs. Moreover the energy dependence of economic growth, which has been falling since mid-19th century, has started increasing because of China dependence on coal. [1]
    • Economic modelling showing GHG emissions could be slashed with little economic damage rests on big assumptions (ie about new technology to power cars and generate electricity; the rest of the world joining in; and negligible cost of phasing out high emission industries). Most greenhouse friendly technologies are not currently cost competitive. Technological change in electricity generation has been limited for 100 years. It may be impossible to reduce emissions in many parts of economy, thus a 30% cut in emissions nationally would probably require a 50% cut in transport and electricity generation [1]
    • Wind power may not be a cheap and efficient way of cutting carbon emissions - because variability of wind requires coal fired stations to be on standby (Lawson M., 'Answer to tough question may be hot air', FR, 12/3/09

    • Electric vehicles could produce higher emissions over their lifetime than conventional vehicles, because of the energy used in making their batteries [1]

  • on the other hand:
    • it was suggested [without detailing how this could be achieved] that deep cuts to carbon emissions in the long term (eg 60% by 2050) were scientifically agreed to be possible, while economic analysis showed that the economic cost would be very small [1]
    • potentially plausible options were suggested based on: phasing down use of coal, oil and nuclear power; increasing use of natural gas to 2030; large increases in energy efficiency; and development of new renewable energy technologies involving solar power, wind and geo-thermal energy [1]. 
      • [[However this assumed rapidly increased global economic productivity of energy use based on past US experience, though some of the latter was due to the shift off-shore of energy intensive production]];
    • achieving large reductions in carbon emissions was suggested to be easy - largely on the basis of the prospective development of clean coal technologies [1];
    • Australia has been seen to have the potential to generate 25% of its electricity needs from geothermal power in the Cooper Basin - though transmission costs to major centres would be a complication [1]
    • Australia could invest more in clean coal technology ( ie carbon capture / sequestration techniques); make renewable energy more competitive; and buildings more energy efficient.  End use efficiency could achieve 30% reduction.  Smart meters showing cost of electricity use can reduce consumption. Transport efficiency standards can be tightened. Urban planning could be rethought and public transport usage improved. While nuclear power is only a long term option - natural gas offers short term prospects. Wind power seems promising renewable source. [1]
    • a UN report argued that the technologies exist, and are affordable in the developing nations which are main source of emission growth, to slow growth of greenhouse emissions and stave off climate change (eg nuclear, solar and wind power, energy efficient buildings and lighting; capturing and storing CO2) [1]
    • huge business opportunities have been perceived in tackling global warming [1]

      • [[This conclusion that will presumably be correct if (a) development of alternative high grade energy technologies is possible and (b) CO2 emissions are the only significant factor in climate change]];

  • it has been suggested that the cost of reducing fossil fuel usage will be inconsequential because future incomes will be greater than today's. [1] However this assumption requires that there be no economic shocks, and attempts to cut the use of fossil fuels (if it proves impossible to develop other high grade energy sources) could give rise to economic shocks which could dislocate growth. It is vital to look closely at the physical relationship between the use of energy / machines and the creation of wealth. This requires assessment by physicists and industrial chemists, rather than environmentalists, economists or climatologists. The economic models cited in the above article deal with the economy in abstract / money terms - and are only valid as long as there is a ready availability of energy to do the mechanical work. At the time of the industrial revolution capitalism allowed the mobilization of financial capital to invest in physical capital (ie machines) that used fossil energy to increase efficiency in mechanical tasks. Increased efficiency reduced costs, which led to an explosion of demand and ultimately to self perpetuating economic growth (which was initially largely a reflection of the value of the work done by machines using fossil energy). Economics now recognizes that knowledge rather than physical capital (ie machines using mainly fossil energy) or human labour is the key component of wealth creation in financial terms - because it provides the scope for firms or regions to change to focus on functions in which a competitive advantage derived from that knowledge allows high productivity to be achieved (in money terms). But there remains an unbreakable link with the escalating use of fossil energy to power the machines that (a) help with knowledge 'work' and (b) do the physical construction and the manufacturing that those with high knowledge-based incomes buy (now often from the developing world).
  • the economic impact of higher energy prices (or reduced availability) can't be assessed just in terms of financial models.  For example if a global 'peak oil' event resulted in large price increases and induced a future steady reduction in motor vehicle usage, this could have multiplier effects well in excess of those implied by the small percentage of GDP that the cost of oil represents by disrupting the functioning of cities (ie require rearranging transport systems, and where people live and work);
  • many companies are falsely claiming to be carbon neutral for public relations purposes - but to be truly neutral there would be a need to consider the emissions in the entire production chain which would be no easy task, and likely to be very costly [1];

  • the direct carbon emission impact that households have is only 1/3 of their total [1];

  • the Business Council of Australia has argued that adjusting to reduced carbon emissions will be difficult [1]

  • greenhouse gas abatement schemes promoted by Australian business would make no measurable difference to climate change [1]
  • CO2 emissions are not the only environmental challenge that needs attention, and unconditional determination to reduce emissions may make it more difficult to deal with other hazards (see below);
  • because economic development in emerging economies is often energy intensive, it would be impossible to have any significant effect unless any efforts are global. 75% of global greenhouse gas emission increase by 2030 will occur in developing countries [1];
  • a 'cap and trade' regime for carbon emissions is likely to be the best post Kyoto arrangement, with global targets allocated amongst countries. Targets might ultimately be based on population - but initially this would need to be based on existing usage [1]. However this would result in large transfers of wealth:
    • from developed nations to developing world (if targets are based on population), and this would dramatically increase the value of currencies in the developing world and thus collapse their other exports [1]. [Remaining underdeveloped, and thus having low greenhouse emissions, could become the main source of wealth available to such populations];
    • from developing to developed countries (if targets are based on existing usage) because the latter can relatively easily increase their energy efficiency [1]
  • while emissions trading might allow emission rights to move to those who would best use them - but this provides no guidance on who should receive them in the first place, and it would be hard to do this fairly [1]
  • efforts to reduce GHG emissions have been very costly and produced no benefits. Claims that reductions can be achieved at minimal costs were based on insane assumptions about the value of yet undeveloped technologies. Such claims were part of a general patter whereby Western leaders were not willing to tell the electorate the truth about the high cost of shifting to a low-carbon economy [1]

Non 'Business as Usual' Solutions could be Hazardous

While technological advances may allow high grade clean energy sources to be identified, if this is not achieved then unconditionally reducing fossil energy consumption (which would be required to moderate the CO2 component of the greenhouse effect) could result in economic crises, conflicts and perhaps billions of deaths over the next few decades. 

Thus targets set for reducing carbon emissions, that are not conditional upon the development of high-grade alternative energy technologies, would be either unrealistic or potentially dangerous.

Why? The whole history of humanity for tens of thousands of years has been one of population growth encountering environmental constraints that  were overcome by the more intensive use of energy.

Would it be possible to reverse this peacefully, or would less overall energy use from now on mean fewer people - perhaps a lot fewer?

Early humans were hunter-gatherers. A key factor in the growth and spread of their population was the domestication of fire (to exploit the solar energy captured in wood) which allowed: an expansion of human's geographic range into colder regions; better defence against predators; and improved ability to use available foods.

However, while one can't be certain about exact figures, the 'carrying-capacity' of the earth for humans living hunter-gatherer lifestyles was probably only something like 50m. When hunter-gatherers encountered environmental limits (about 13,000 years ago) these constraints were overcome by the development of agriculture which mobilized solar energy more efficiently.

When agrarian populations encountered limits to what could be achieved by the use of solar energy - a few hundred years ago at densities roughly equivalent to a global population of (say) 500m - fossil energy sources were mobilized, and this allowed (a) more efficient mechanised agriculture and (b) the development of vast cities productively involved in diverse other industries.

In recent decades, solutions to resource limitations and adverse environmental impacts of population and economic growth have been solved by more intensive energy use. The recent shift into knowledge and service industries in advanced economies, which has reduced their energy intensity, is somewhat misleading because energy consumption on their behalf has merely followed the shift of much manufacturing to the developing world.

There is a potential for highly destructive political instabilities if the global economy were disrupted by reduced energy consumption through unconditional cuts to CO2 emissions. Consider for example:

  • global financial imbalances that appear to be associated with a 'clash' of civilizations and have the potential unless carefully defused to lead to a worse economic crisis (and consequent political conflicts) than in the 1930s (see Structural Incompatibility Puts Global Growth at Risk). The seems to be a relationship between these risks and the financial instabilities that emerged in 2007 (see Financial Market Instability: A Many Sided Story);
  • the lack of any effective system of global governance, arguably due to difference perceptions of the nature of a desirable global system - as revealed by (for example) the failure of international community to reach agreement on what to do about the risk posed by terrorists with weapons of mass destruction (see The Second Failure of Globalization?).

Moreover, even if short term crises could be avoided, the current global population of 6bn (or anything like it) could probably not be sustained in the longer term in low-energy economies. Could enough food for 6-9bn people globally be produced by neo-agrarian technologies? Soils are depleted and water scarce in many places, and require energy intensive fertilizers, faming methods and water supplies for current levels of food production. Also, though in a neo-agrarian world, (say) 50% of people would work in agriculture (as compared with 5% in industrial economies), what would the 3-4bn people living in future in dispersed villages who were not engaged in agriculture do for a living without cheap energy sources? It might be that they would be most 'productively' be occupied if recruited into armies to capture others' treasure left over from energy-intensive times (and wipe one another out until the global population got back to a sustainable neo-agrarian level - say 500m).

The Garnaut review of climate change policy in Australia apparently sees the problem in terms of breaking the link between energy consumption and economic growth [1], and thus must confront the above challenges.

There are many other environmental challenges that need to be met in the longer term, for which energy-intensive solutions may be required that could be rendered impossible if unconditional reductions in CO2 emissions resulted in reduced overall energy usage. Examples of other challenges that appear to require simultaneous solutions include:

  • the toxic effects of many chemicals [1];

  • declining food quality that seems to be associated with first world 'malnutrition' as revealed by the escalation of obesity and the chronic degenerative diseases that threaten to overwhelm health systems. This may require solutions that include 're-engineering' the food chain to bring producers and consumers closer in time and space;

  • loss of biodiversity, which may be an environmental challenge with more serious potential consequences. Analysts have suggested that (say) 50% of species could be lost in 50 years (Leakey R etal The Sixth Extinction, 1996). When such events have occurred previously in earth's history they have been followed by the emergence of new species to occupy available ecological niches. At risk could be the Pleistocene environment in which human beings have become the dominant species over the past 5m years;

  • the risk to bee populations on which pollination of many different types of foods depends [1]

  • human consumption of about 40% of global biomass - which leaves limited biological resources for other species;

  • limitations of available fresh water and soils;

  • potential pandemics.

How is Success Determined?

If emissions can be reduced effectively, it will take 10-30 years for this to have any detectable climatic effect and 100-300 years to get the full effect [1].

If in 5 years, global temperature changes end the correlation with greenhouse gases levels that they have exhibited for the past few decades (eg because other factors have become more significant), will programs to reduce carbon emissions be no longer needed?

Doing Better

Doing Better

In part the uncertainty of the climatic change equation is due to the fact that those who fear the economic consequences of popular solutions or have private interests that are threatened are challenging the consensus view developed though IPCC machinery.

However, the IPCC's consensus view was shaky  anyway - and some are ignoring this in claiming to have identified easy solutions.

The present writer, who had taken as self-evident for years that CO2 emissions were likely to drive global warming, now suspects that overly simplistic claims may be being made to satisfy demands for an 'answer' (any answer) so that political leaders can be seen to be doing something to allay public fears about climate change.

In particular, the IPCC seems institutionally susceptible to bias, and may not have examined the climate change issue squarely because of its narrow terms of reference. It was initially set up to evaluate only the effect of man-made emissions, and focused upon short term (ie about 50 year) correlations to make projections and appeared to pay insufficient attention to the earth's long term climatic history. Moreover it did not appear to seriously evaluate alternative possible explanations of recent events, which is inconsistent with the traditional methods of scientific research.

A UK example of political commitment to research outcomes: In March 2011, the leading role which the then UK Prime Minister (Margaret Thatcher) had played in supporting the establishment of research capabilities to address climate change was noted (Gummer J. ‘Climate change doubters are endangering our common future’, The Australian, 21/3/11). [Her support apparently led to the creation in the mid-1980s of the influential Hadley Centre for Climate Prediction and Research in the UK – which was paralleled by the creation of the IPCC and had similar goals]. Mrs Thatcher was described as “the first major political figure to accept that climate change was happening and that mankind had caused it. She was a scientist by training and she cross-questioned the experts in the way only she knew how. She would have preferred them to have been wrong too. However, the whole assembly of facts, even then, more than 20 years ago, convinced her that we had to act.”

The problem with this is that: (a) every serious student of the subject in the late 1980s (including the present writer) reached the same conclusion as  Mrs Thatcher; and (b) that conclusion apparently created an institutional bias in the climate change theories that it was politically-correct to consider if one wished to gain research funding.

The Stern Review in the UK seems to have been even more professionally unreliable than the IPCC.

Moreover responses from those with a commitment to reducing GHG emissions can be hostile when attention is drawn to uncertainties in the climate science 'consensus'. It might be suggested, for example, that highlighting uncertainties must be based on:

  • "a psychological need to be different from most people, to argue the contrarian view on principle" ;
  • being one of "the front organisations financed by Big Oil or Big Coal"; or
  • "self-interested misrepresentations of selfish and reckless industries. The same kinds of people who used to tell us smoking was harmless".

Furthermore it seems that some advocates see reducing GHD emissions as a kind of religious duty for the future of humanity and the earth, so that even though the science might be uncertain a  'precautionary principle' (which is privately-held but seldom mentioned in public debate) requires action because, if the 'science' is correct, the cost of inaction could be devastating. They seem unconcerned by the possibility that if the 'science' is wrong, the cost of acting could also be devastating.

One advocate suggested the possible need (in Australia) to suspend the democratic process in order to achieve reductions in GHG emissions that he believed appropriate [1].

Whether or not the 'science'  (which science?) is correct, highly emotional adherence to a preferred solution is not likely to be helpful.

The present writer has had previous experience where a political consensus developed behind an agenda which had been incubating for decades (see Towards Good Government in Queensland). Beset with a fundamentalist zeal, 'reformers' surrounded themselves with cronies and 'yes men'; punished anyone suggesting alternative viewpoints; and treated their long held ideology as 'the solution' to current problems though their view of the situation was out-of-date and biased. Because politicisation of the Public Service prevented any 'reality check' on the populist proposals, the consequences were disastrous (see Queensland's Worst Government).

Attention to alternative possibilities related to climate change is potentially at risk of being stifled and ignored by political populism, and this could be just as damaging as the overly simplistic assumptions that the US administration apparently made about what was required to create a politically and economically successful Iraq as a model for the Middle East.

It will do no one any good to put in a huge amount of effort to 'solve' the climate change problem if that effort does not actually address the real current cause of the problem (eg if carbon emissions are not the only significant factor in climate change) of if reducing carbon emissions (a) is not as trivial as enthusiasts assume or (b) makes it difficult to find solutions to other possibly equally important challenges.

As Mark Twain suggested:

"It ain't what you don't know that gets you into trouble. It's what you know for sure that just ain't so."

The IPCC's 'consensus' now seems to be being challenged by a diversity of scientists and other professionals who are outraged that the scientific debate has been pre-empted and politically declared settled after hearing only one side of the debate. A significant revision of that consensus seems possible in 2-3 years time, though those whose beliefs have become a quasi 'religion' might take much longer to accept this.

In early 2008 a draft review of Australia's potential response to climate change by Professor Ross Garnaut, which paralleled the UK's Stern Review:

  • suggested huge reductions in GHG emissions (ie 70-90% by 2050)  and pressure on other countries to do likewise [1, 2]. This conclusion about the need for economically disruptive change was the logical consequence of assuming that the IPCC's view of climate science is correct; 

  • acknowledged professional critiques of the IPCC's work and the possibility that its approach was not objective, and thus suggested expanding scientific work beyond the views of the IPCC [1].

The science of climate change has been mismanaged. The IPCC was created to investigate anthropogenic climate change - and is dominated by persons interested in that theory. Since it appeared (in the early 1990s) that climate change might be occurring, IPCC's emphasis has been on proving that its theory is a possible explanation rather than evaluating all possible hypotheses. The IPCC's approach has been most 'unscientific'.

The basic precaution of properly funding the examination of alternatives is now 15 years over-due and arguably an urgent priority.  The IPCC estimates a 10% probability that global warming is not due to human GHG emissions. However as Garnaut's review is showing, if the consensus 'science' is incorrect, the cost of acting on it could be devastating.

Finally, even if it were to be shown that climate change can't be influenced very much by reducing CO2 emissions, there might still be a case for expediting a shift to more renewable energy sources (eg to reduce dependence on oil from the politically unstable Middle East).

Moreover, given the irresolvable uncertainties of human attempts to understand the true complexity of any environmental system, a general orientation towards minimizing the human 'footprint' in the environment (and thus unpredictable consequences of human action) may make more sense than initiatives focussed on the assumption that CO2 emissions are virtually all that matters.

Addendum A : Stern Review Critique

Brief Outline of 'The Stern Review: A Dual Critique: Part 1 - The Science'
(Carter R etal., , World Economics, v7, n4 October–December 2006)

See also: a brief outline of 'The Stern Review: A Dual Critique - Part 2: Economic Aspects'

The Stern Review outlined climate science and analysed the impacts of climate change. Its credibility rests the accuracy of the science. It concluded that: the scientific evidence is overwhelming: climate change is a serious global risk, and demands an urgent response.

But the evidence for dangerous change is far from overwhelming, and the Review's picture of the debate is neither accurate nor objective. It understates the uncertainty about the evolution of poorly understood complex systems. Its treatment of sources and evidence is selective and biased. This makes the Review a vehicle for alarmism. The assumption that peer review guarantees quality and objectivity is false - as climate science peer review is inbred and insufficiently thorough.

1. Flaws in the Alarmist Paradigm:

The alarmist view of climate science

Stern stated in OXONIA lecture of January 2006: “in August or July of last year, [he] had an idea what the greenhouse effect was but wasn’t really sure”. After this he quickly adopted the views of the Hadley Centre for Climate Prediction and Research - which are in line with IPCC, but not universally held.

Many Review claims have been challenged in the literature. It presumed that:

  • moderate increases in CO2 levels will lead to major / damaging climatic changes;
  • recent climatic changes can be blamed on emissions of ‘greenhouse gases’ (CO2 in particular); and
  • climate models are sufficiently accurate for major policy decisions.

The Review fails to take account of the uncertainties and gaps in knowledge of climate science, and ignores continuing debates about climate change mechanisms and impacts. Like its sources, it relies on model projections rather than established data. By exaggerating climate alarm it  fails to provide a sound basis for policy.

Mishandling of uncertainty

The Review cautions about modelling, yet fails to heed its own warning.

Many unqualified Review statements attribute causality or state what “will” happen to climate or the biosphere - on the basis of computer models. The IPCC by contrast warned that in dealing with a coupled non-linear chaotic system,  long-term prediction is impossible - and talks of a ‘cascade of uncertainty’ which extends to biophysical and socioeconomic impacts.

The Review tries to deal with these uncertainties by comparing thousands of model runs under varying assumptions - but ignores the possibility that CO2 emissions may have minor or benign effects. The Review draws on the upper end of risk distributions and presents these as representing the range of credible outcomes.

Climate prediction: is it a mature or a new science?

The Review assumes incorrectly that climate prediction is a mature science. It is a new area emerging from weather forecasting, aided by more computer power.

The IPCC, by contrast:

  • rated “scientific understanding” of 9 out of 12 identified climate forcings as low;
  • highlighted the limitations of climate models; and
  • recognised large uncertainties about how clouds react to climate forcing.

Since then, major scientific papers have claimed, that:

  • the forcing of methane has been 50% underestimated;
  • half 20th century warming might be due to solar changes;
  • cosmic rays could have a large effect on climate; and
  • aerosols are more important than greenhouse gases.

These are ignored in current climate models except that aerosols are used, without justification, to reduce otherwise excessive greenhouse warming forecasts.

Also, as late 20th century temperature changes were only a few tenths of a degree,  model simulations of external forcings may not be needed as an explanation. Such minor changes may be natural (eg due to variability are oceans that are never in equilibrium because of exchanges between the abyssal heat reservoir and the thermocline), together with changing atmospheric circulation that deposits heat in regions with differing infrared opacity. Models may never be able to deal with this.

Exaggerating warming trends

OXONIA Technical Annex, said that “The rate and scale of 20th century warming has been unprecedented for at least the past 1,000 years.”

But there is only 50 years of accurate global measurements of temperature and GHG. The only global records of measured temperature come from weather balloons (since 1958) and satellites (since 1978). These indicate a gentle warming trend of 0.1–0.2 degrees C/decade (at the low end of the trends the Review considers). Also much of the increase in balloon data occurred in 1976–77. Since 1979, satellite data show little change, especially in the tropics and Southern Hemisphere.

Variations can be due to volcanic eruptions and El Nino events, and are not alarming anyway. Nor is there any sign of acceleration.

The rates of modern temperature change are within the rates of minor warmings and coolings inferred for the Holocene (eg in ice cores).

Using the ‘global average temperature’ statistic since 1860 suggests that late twentieth-century warming is similar to (natural) warming between 1905 and 1940.

Comparisons over longer and more climatically relevant time spans (using data from ocean seabed and polar ice cap drill cores) suggests that late 20th-century warming represents a high on a sinusoidal, millennial temperature pattern of possible solar origin. Recent warming was at a similar rate, but of lesser magnitude, that the Mediaeval, Roman and Minoan warm periods.

The Review’s claim that “An overwhelming body of scientific evidence indicates that the Earth’s climate is rapidly changing, mainly as a result of increases in GHG caused by human activities” is without foundation.

Reinventing climate history

Public and governmental concerns over anthropogenic global warming soared with the media use of a graph from the IPCC’s Third Assessment Report of 2001, which showed nine centuries of near constant temperatures followed by a dramatic rise in the 20th century correlating with the rise in CO2 concentrations.

The Mediaeval Warm Period (MWP), previously believed much warmer than now, and the colder Little Ice Age (LIA) did not appear on this graph, which was dubbed the ‘hockey stick’ and became the basis of claims that natural climatic variation had been very small for a thousand years.

Other temperature reconstructions are said to support the ‘hockey stick’, but they may be questionable.

Many doubt the ‘hockey stick’ as  LIA and the MWP are well documented - and suggest that natural factors have a far more significant role in climate changes than the ‘hockey stick’ suggested. They put in question claims that recent warmth can only be explained by human-induced increases in GHG.

Despite implying that the debate on the science of climate change is now settled, the Review had  to admit that major doubts exist over the ‘hockey stick’.

Recent reports confirm that  the hockey-stick shape is invalid.

The Review now says  “Climate change arguments do not rest on ‘proving’ that the warming trend is unprecedented over the past Millennium". It also claims that “Much of the debate over the attribution of climate change has now been settled as new evidence has emerged to reconcile outstanding issues.” - without saying what the “new evidence” is.

Earlier Stern Review documents cited the ‘hockey stick’ as valid, though the Review now treats it as irrelevant.

But climate models are tuned to the low estimate of natural climate variability put forward by the IPCC in 2001. If the world was much warmer in mediaeval times, the models could not replicate this without giving more weight to natural variability and their ability to identify anthropogenic forcing would be decreased.

Attribution studies: circular reasoning

The Review’s confidence that greenhouse gases are likely to give rise to major, deleterious climate change is largely based on a single Hadley Centre paper prominently used in the IPCC Third Assessment Report.

However to simulate observed trends, the Hadley Centre had to eliminate about two-thirds of the anthropogenic greenhouse forcing with countervailing aerosols (the net result being referred to as anthropogenic forcing) -ie the model exaggerates the actual warming.

Also as aerosol forcing is poorly known, it was felt that calculating how much aerosol forcing is needed to cancel greenhouse forcing is as good a way of estimating the aerosol forcing as any.

The IPCC’s claim that the model had simulated observations is circular. In actuality, even the sign of aerosol forcing is unknown.

In a more rational and less politicized environment, it would be considered that the models are exaggerating the response to anthropogenic greenhouse forcing.

This circular reasoning undermines claims that models prove warming could only be caused by forcings. Advocates of the idea that the response of the real climate to radiative forcing is adequately represented in climate models must prove that they have not overlooked a single nonlinear, possibly chaotic natural feedback mechanism - an impossible task.

The IPCC cautioned in relation to the Hadley study that it showed that the forcings included are sufficient to explain observed changes, but do not prove that other forcings were not also involved. 

The Review disregards these warnings and  asserts that “more than a decade of research and discussion… has reached the conclusion there is no other plausible explanation for the observed warming for at least the past 50 years”.

The Review does not mention other plausible explanations that have been advanced in professional literature, eg:

  • correlation of temperature trends with local heating caused by urbanization and industrialization;
  • using longer-term geological evidence suggests minimal impacts from greenhouse gas forcing (eg that recent global warming years is just a short episode in the geologic history - most likely due to increased solar and tectonic activities (with human impacts of 0.01°C of about 0.56°C total average atmospheric heating during the last century);
  • using the instrumental record and long term geological evidence to ‘predict’ the current warming phase, while also suggesting cooling over the next few decades;
  • both NASA and the Russian Academy of Sciences now predict cooling early in the twenty-first century as solar activity decreases.

Carbon dioxide in perspective

It is important to distinguish CO2 emissions, CO2 concentrations in the atmosphere, and climate forcing (which is all that is relevant to potential warming).

Emission reductions proposed by the Kyoto Protocol would have only a minuscule effect on atmospheric concentrations, while increments in these concentrations would have a diminishing impact on climate forcing.

A doubling of CO2 represents a forcing of about 3.7 Watts per square meter. Since anthropogenic greenhouse forcing is already estimated at about 2.7 Watts per square meter (50+% due to CO2, and half of the rest to methane) then we are already about three quarters of the way to an effective doubling of CO2, yet we have experienced less warming than such forcing would suggest.

The Review assumes that future CO2 increase will have much greater effects than in the past.

Changes in CO2 concentration don't correlate well with the 0.6 degree C increase in ‘global average temperature’ in 20th century. Temperatures increased between 1905 and 1940 before any greatly increased industrial emissions of CO2. The rapid post-1940 increase in CO2 emissions was accompanied by a falling temperature between 1945 and 1965. The hockey-stick curve conceals these problems.

Even the direction of causality is uncertain. Ice core data indicate that, in ancient climate changes, increases in temperature preceded increases in CO2 by hundreds of years.

It is estimated that a doubling of CO2 would, other factors kept constant, result in a global mean warming of about 1 degree C. But alarming predictions all require that water vapour and clouds act to amplify the impact of CO2, though water vapour and especially clouds are poorly modelled, while the underlying physics for determining their behaviour is missing or even unknown. The governing equations of fluid dynamics (Navier-Stokes) have resisted solution for 100 years. 

The Review’s only substantive remarks on water vapour feedback are irrelevant. These relate to Lindzen’s 1990 suggestion for a mechanism whereby a warmer surface might lead to a drier tropopause region, even though it has long been shown that changes in water vapour at these levels would have marginal impact on climate.

For some time now it has been recognized that the real feedback in the atmosphere likely consists in simply changing the relative areas of moist / cloudy and dry / clear regions.  Recent work supports the existence of such a mechanism, the strength of such a mechanism, and the failure of current models to replicate. The process (sometimes referred to as the Iris Effect) would reduce sensitivity to a doubling of CO2 to less than 0.5 degrees C

2. Overstating Climate Impacts

The Review’s treatment of impacts is alarmist because of two systematic biases.

In scenarios analysis only fossil fuel intensive options were considered in high-growth scenarios - used as the base scenario. It forecast 15bn global population in 2100 - which has a very low probability (and is 50% over UN's medium population scenario). This inflates emissions and the numbers at risk for each of the climate-sensitive hazards, and hence the consequences and costs of dealing with them.

A second bias in consideration of climate impacts is reliance on papers that assume either that human beings will do nothing to combat adverse impacts of climate change, or will only use existing technology. IPCC’s scenarios, by contrast, take account of advancing technologies.

The Review’s consideration of various climate impacts is biased towards damaging or disastrous outcomes, eg in terms of

  • Hunger and agricultural productivity (by ignoring technologies developed to cope with the impact of climate change, and the fertilization effect of increase CO2 levels). This results in forecasting “250–550 million additional people at risk” of hunger, rather than declining numbers of hungry people, even for a temperature increase of up to 3.5 degrees C.
  • Ecosystems and extinction risks - which the Review states is subject to uncertain information only after drawing conclusions based on that information - ie that many species will be at risk of extinction. A basic issue is whether climate suitability studies are even able to predict extinction risks under different climatic regimes. The Review also ignores writings about carbon fertilisation, and other factors, that may reduce habitat loss and increase water use efficiency of plants, thus reducing pressures on ecosystems and biodiversity. Lower habitat loss would also conserve migration corridors, while changes in forest productivity (because of higher CO2 concentrations) would similarly promote biodiversity. In sum, the Review’s assessment of ecosystem and extinction risks are a worse-than-worst-case scenario
  • Water availability and water shortages - ideas about this are based on Arnell’s studies which ignore technological adaptation and advance;
  • Melting ice sheets - 2 of 4 papers relied on to show  “significant melting and an acceleration of ice flows near the coast” of Greenland and the possibility of “irreversible” melting of the ice sheet show a slight net gain in the mass of the ice sheet (1992–2003), as  ice is building up inland due to higher snowfall. Also temperature around the coast, though now rising, is still lower than in 1940, The Review fails to say that Arctic temperatures are now like the 1930s, or that Antarctic ice is increasing - which could lower global sea level.
  • General health impacts - Review relies on sources that have biased agendas and defective methods. The complex array of variables requires data collection for decades to reach sound conclusions - requirements ignored to get quick conclusions
  • Malaria and dengue fever estimates are based on sources that ignore human adaptation as incomes increase. Eliminating these diseases has long been possible, but limited by poverty.
  • Extreme weather - Stern stated earlier that many uncertainties had been resolved in favour of alarm, but that “attribution of current weather events to human-induced climate change” was controversial. However specific weather events cannot be ascribed to global climate changes, let alone to any human-induced component. But using selective sources, and without evidence Stern claims “The world has been experiencing more extreme weather events.” - a view contradicted in the latest IPCC report. Trends in severe weather events are hard to detect because of their rare occurrence and spatial variability. Studies since the last IPCC report have re-confirmed this. Contrary to most projections, the 2006 hurricane season in the North Atlantic was mild, showing the poor knowledge the climatological community has about what drives storms and extreme weather, and the folly of long term forecasts based on current knowledge even when models have been “trained” with past data.

3. Professional Standards

The scandal of non-disclosure and poor archiving

Given the global impact of the ‘hockey stick’, governments should be insisting on strict professional standards of archiving and disclosure, but most do not. Poor disclosure, verification, and media reporting in climate predictions are common.

Data volume makes verification impossible without help of original workers. The 1998 Mann et al. ‘hockey stick’ paper was questioned, but so poor was the archiving of its data and computer programmes that it took 8 years to show its defects.

By refusing to release data / programmes, researchers prevent checks and argue that their thesis has not been falsified. Some publicly-funded climate scientists maintain self-regulation solely by peer review (with British Government and IPCC support).

The global temperature series used by IPCC is basic data equivalent to CPI but is not produced by a statistical agency working under transparent protocols. It is produced by Climatic Research Unit (CRU) at the University of East Anglia (closely affiliated with the Hadley Centre), which refuses to allow external study of how they produce this data. This is astonishing as scepticism and efforts to falsify hypotheses are fundamental elements of science.

Similarly Mann had refused to help researchers trying to replicate his ‘hockey stick’ diagram - as it was considered private intellectual property.

Public policy should not be based on private and unverified intellectual property.

Inadequacies of peer review

Policymakers rely too much on peer review which only ensures quality in journal papers appearing, not that their hypotheses are correct. 

Bias in science is seldom intentional, but is more likely when consensus is sought. 

A prominent observer argued that exaggerated claims pass internal quality checks easily, but reasoned and accurate claims find an unwelcome audience - because the former are seen to lead to 'good' policy and career success.

Papers are now published in prestigious journals on global warming with almost no checking yet valid criticisms of the Mann et al. paper were rebuffed by many journals (based on peer review).

The UK government continued to defend ‘hockey stick’ work because it had been peer reviewed - which simply missed the point.

The IPCC's peer review process is also unsafe, eg dissenting panellists have withdrawn leaving a very narrow group.

4. Conclusion

The Stern Review is biased and alarmist. It:

  • fails to acknowledge knowledge gaps and uncertainties;
  • credulously accepts hypothetical, model-based explanations of climate causality;
  • overestimates climate impacts with an implausible population scenario and one-sided treatment of the impacts literature, including use of advocacy documents;
  • lacks due diligence in evaluating key research studies, despite their lack of disclosure of data and methods; and
  • lacks concern for the defects and inadequacies of the peer review process.

The Review relied on a few people and organizations with a history of alarmism. Most  research cited does not make a good case for the Review's conclusion.  Contrary research and facts are consistently ignored.

Annex - Mishandling of Basic Observational Data:

The Review’s presentation of data on the key parameters of the greenhouse equation - emissions, concentrations, and forcing - are inconsistent and unreliable. It puts the worst possible face on emission trends. In particular:

  • Claims that CO2 (the largest share of greenhouse gases) grew 2.5% pa (1950 and 2000) are only true if natural emissions are ignored (as Review persistently does). This claim obscures the fact that the rate of emissions growth fell in that period;
  • Review claims the warming effect due to all (Kyoto) greenhouse gases emitted by human activities is equivalent to 430 ppm of carbon dioxide - which is wrong as (if the current CO2e level is 430 ppm), then the warming effect of (Kyoto) GHGs emitted by man is 150 ppm of CO2, as 280 ppm of CO2 was already in the pre-industrial atmosphere;
  • The difference between human emissions and concentrations is over-simplified. CO2e (equivalent) levels are concentrations, and don't simply increase due to human emissions. Most human GHGs are reabsorbed by the biosphere (eg for 60% of CO2) or destroyed by atmospheric chemical reactions (eg for methane, nitrous oxide, etc.). The Review quotes inconsistent figures for CO2e levels. OXONIA Lecture gives 425 ppm. The Review quotes 430 ppm, but this excludes CFCs because they are regulated by the Montreal, not Kyoto, Protocol. Including CFCs, the Review states, the figure would be 445 ppm. Review also quotes a current level of 450 ppm for Kyoto gases only;
  • Review claims “The rate of annual increase in GHG levels is increasing” - which data does not support. This skews conclusions to worst case scenario.  Taking 3 ppm as a minimum future increase is too pessimistic, as likely 2006 increase is 1.7. Projected 2035 concentrations of 550ppm CO2e require 4 ppm pa increase - higher than peak years (1976–1988). High forecasts are the result of ignoring hard data on concentrations, and using models to predict concentrations from projected emissions;
  • Real  concentration of methane has not increased for 7 years, contrary to IPCC modelling and scenarios. Review mentions possible massive escape of methane from thawing permafrost or ocean hydrates, but ignores the data;
  • Review correctly states that “warming effect of CO2 rises approx logarithmically with concentration" but wrongly asserts that methane and nitrous oxide concentrations have a linear relationship to forcing. In fact, forcing declines with methane concentration.

All data errors follow a consistent patter - total change to date (substantial, but harmless) is minimised, but future changes (said to have dire consequences) are exaggerated.

Garnaut Climate Change Review: The Need for a Broader Approach

Garnaut Climate Change Review: The Need for a Broader Approach (Email sent 1/6/11)

Garnaut Climate Change Review

Re: Update 2001

From a quick perusal of the Introduction to this update, I should like to draw the review team’s attention to three matters which seem to require additional attention.

First, as I understand it, the IPCC argues that CO2 emissions account for only about half of the effect of the greenhouse gases whose increasing levels have raised concern about global warming. However, while there is a brief mention of other significant greenhouse gases in Chapter 1, there seems to be no serious discussion of anything apart from reducing carbon emissions in the report.

Second, the report endorses pricing carbon emissions as a basis for inhibiting climate change and presents an economic analysis of the costs of doing this and of appropriately compensating different segments of the community. However, the global ‘peak oil’ event seems to be increasingly regarded as imminent (see General Notes on Peak Oil), and likely to result in a substantial increase in some energy costs (and thus have similar effects to pricing carbon emissions). Moreover it could be economically disruptive in ways that could impact on greenhouse gas emissions (eg by triggering changes in international trade and travel, as well as in regional transport and urban systems). Overall there seems to have been a grossly inadequate effort by Australia to analyse and prepare for the ‘peak oil’ event. In particular it seems that the Climate Change Review’s apparent failure to mention the inter-relationship with pricing carbon emissions is a serious limitation.

Third, the review update starts (in Chapter 1) by asserting that the mainstream view of climate science is increasingly regarded as reliable. However, this is hardly surprising as there does not yet seem to have been any serious resourcing of attempts to falsify the mainstream anthropogenic greenhouse gas theories of climate change by those who believe that the mainstream view might be overly simplistic (see Finding the Truth on Climate Change). Until this necessary stage of the scientific process is actually undertaken, the confidence that the review update expressed in mainstream climate science may be unjustified.

John Craig

Overcoming Climate Change Paralysis

Overcoming Climate Change Paralysis - email sent 23/4/15

Mark Triffitt and Travers McLeod,
University of Melbourne

Re: Hidden crisis of liberal democracy creates climate change paralysis, The Conversation, 22/4/15

Your article points to the undeniable fact that liberal democracy has difficulties dealing with challenges as complex as climate change. Some suggestions about this difficulty (which were developed in 2003 without any reference to climate change issues ) are in Challenges to Democratic Institutions (in Australia's Governance Crisis and the Need for Nation Building). The latter included suggestions added in 2010 (see A Nation Building Agenda) that those constraints might be reduced by developing stronger institutions – and doing so parallels, though would be by no means identical to, the solutions suggested in your article.

However, in relation to climate change, it seems likely that reforms in the area of climate science are also required to expedite progress. Encouraging (long overdue) scientific attempts to falsify mainstream climate science should show either: (a) that the many non-mainstream speculations that divert public attention are wrong; or (b) that mainstream climate science is overly simplistic (eg as suggested in Finding the Truth on Climate Change, 2007). In either case, public confusion about the issue should be reduced, and rational action through liberal democracies should be expedited.

I would be interested in your response to my speculations

John Craig

Malcolm Turnbull's Opportunity to End the Climate Change 'Culture War': Commission a Serious Review of Believer's Climate Science

Malcolm Turnbull's Opportunity to End the Climate Change 'Culture War': Commission a Serious Review of Believer's Climate Science - email sent 28/10/15

Paul Kelly
The Australian

Re: Malcolm Turnbull Builds New Climate Coalition, The Australian, 28/10/15

Your article suggested that the Prime Minister (whom you described as a ‘climate change believer’) has a strategy to end the ‘culture war’ over climate change. However, while it may be politically convenient to believe that climate science is well established and thus beyond debate, this does not seem to be so scientifically. Thus the best way to bring an end to the current stalemate (and thus reliance on quasi-religious ‘belief’ as the basis for determining a policy response) would undoubtedly be for Mr Turnbull to commission a serious effort to falsify mainstream climate science’s claims that climate change is mainly driven by human CO2 emissions.

My Interpretation of your article: Malcolm Turnbull has again displayed his business / rationalist outlook by bagging the ideology of climate change (breaking with both the green lobbies and Tony Abbott) and signaled a strategy to bury the culture war over climate change. Proposals that will appeal to the mainstream are envisaged – with practical action to combat climate change without punishing economy. Turnbull’s status as a climate change believer is fundamental to this strategy. 26-28% reduction targets for 2030 would stay in place. Turnbull clearly indicated his intent to take the ideology out when introducing Australia’s new chief scientist. He has no time for ideological and religiously-inspired obsessions that have bedeviled Australia’s response. He championed renewable energy while arguing that coal remained fundamental to the energy mix. This disappoints both those who love and hate coal. He suggested that the objective in relation to global warming was to reduce emissions.

There are reasonable (though not certain) grounds for doubting that the key to dealing with global warming is to reduce CO2 emissions (see Climate Change; 'No time to lose' in doing exactly what? 2006). This referred to a very large number of often-still-unresolved concerns about the validity of ‘believing’ that CO2 emissions are the main driver of climate change. For example, CO2 accounts for only about half of humanities’ greenhouse gas emissions; there are reasonable grounds for suspecting that atmospheric CO2 levels are a consequence, rather than the primary cause, of climate change; defects are seen to exist in the IPCC’s climate models that explain why those models did not predict the pause in global warming that has been observed over the past 18 years; and non-anthropogenic factors have been more than sufficient to drive massive climate change in the earth’s fairly recent history - and some reputable scientists argue that their influence continues to dominate.

Rather than merely debating the best way to reduce CO2 emissions on the basis of quasi-religious ‘belief’ that this is the key to dealing with climate change, it has long been desirable to continue the process that is vital to truly validate scientific conclusions (ie attempt to falsify those conclusions). How this might be achieved was suggested in Finding the Truth on Climate Change (2007). Doing so could take the ideology out of climate change debates – by resolving the dispute between climate change ‘believers’ and skeptics one way or the other.

Doing so could well be critical to Australia’s future economic prospects because of the economy’s current significant level of dependence on coal / natural gas exports. It has recently and reasonably been suggested that the “UN’s COP21 climate summit in Paris in December is likely to be a landmark event that starts to shut the door on parts of the fossil fuel industry” and that this might have legal ramifications by enabling those who suffer damage as a result of climate change to bring claims for compensation (Evans Prichard E., Fossil fuel companies risk plague of 'asbestos' lawsuits as tide turns on climate change, The Telegraph, 27/10/15). In an environment in which claims for compensation for the effect of climate change were proceeding, it would be critical to have the clearest possible understanding of whether or not it really is reasonable to ‘believe’ that human CO2 emissions are the primary driver of climate change.

John Craig

Significant Climate Science Issues Remain Unresolved

Significant Climate Science Issues Remain Unresolved - email sent 18/12/15

Professor John Quiggin,
University of Queensland

Re: Climate claims a victory in the culture wars. Inside Story, 17/12/15

Might I respectfully suggest that it is nonsense to claim that attempts to resolve issues related to climate science are in some sense a ‘culture war’. Uncertainties about the presumption that there is a simple / predictable link between CO2 emissions and climate change remain very real and significant (eg see Finding the Truth on Climate Change, 2007+ and The Science is Uncertain 2006+).

At the recent Paris conference, the world’s political leaders all decided to ignore the uncertainties about climate science – and commit to doing what would need to be done if mainstream theories are correct. However, as numerous commentators have pointed out, the reality of what resulted seems to be much less than the politicians suggested would be needed if mainstream climate science is actually correct. For example:

The uncertainty that remains about what is actually needed can only be resolved by taking seriously the concerns of the increasingly numerous and prominent scientists who are pointing out that there are problems with the theories that were taken as gospel in Paris. Those uncertainties can’t be resolved, as your article claimed, by asserting that the issue simply comes down to a ‘culture war’. Australia still has the potential to make a major global difference by initiating action to resolve those scientific uncertainties (eg as suggested in Malcolm Turnbull's Opportunity to End the Climate Change 'Culture War': Commission a Serious Review of Believer's Climate Science).

John Craig

CO2: A Forcing or a Feedback

CO2: A Forcing or a Feedback - email sent 26/3/16

Katrin Meissner and Katlin Alexander
University of NSW

Re: Mass extinctions and climate change: why the speed of rising greenhouse gases matters, The Conversation, 24/3/16

I was very interested in your account of what is now being learnt about changes in climate / CO2 levels (and the consequences for life on earth) over the past several tens of millions of years.

However it seems to me that attention should have been paid to the question of whether CO2 is the key forcing or to some extent a feedback in those processes. As you will be well aware water vapour has the greatest greenhouse effect but is ignored in analysing climate change because it is recognised to be largely a ‘feedback’ from other factors that are taken to be the relevant ‘forcings’.

The reason that it seems to me to appropriate to consider whether CO2 should be regarded as a forcing or a feedback is outlined in Finding the Truth on Climate Change (2007). This includes reference to: (a) an article that James Hanson (then NASA’s top climate scientist) sent me in which he suggested that CO2 should be regarded as a feedback over geological time scales; and (b) the conclusions by other climate researches that CO2 levels seem to peak after temperatures peak - which again suggests a feedback rather than a forcing role for CO2 under some circumstances.

Your article made several references to feedback effects, but did not consider the extent that this might apply to CO2.

I would be interested in your response to my speculations

John Craig

Avoiding Scientific Scepticism: The Main Tactic of the Prevailing Climate Consensus

Avoiding Scientific Scepticism: The Main Tactic of the Prevailing Climate Consensus - email sent 11/8/16

Professor Stephan Lewandowsky
University of Bristol

RE: The Galileo gambit and other stories: the three main tactics of climate denial, The Conversation, 11/8/16

Your article pointed out that Senator Malcolm Roberts' scepticism about the prevailing climate consensus was based on: (a) a case in which an outsider (Galileo) upset the scientific consensus of his day; (b) a perceived conspiracy; and (c) what he perceived as a lack of empirical evidence. You also argued that such claims were: (a) paranoid; (b) conspiratorial ramblings; (c) denying facts that are supported by the overwhelming body of evidence; (d) pseudoscience and science denial; (e) quackery; (f) couched in sciency-sounding terms; (g) contrary to thousands of peer review scientific articles; and (h) and contrarian talking points that were judged to be misleading and fraudulent by expert statisticians and data analysts.

Encouraging efforts to falsify scientific theories is foundational to scientific progress. Doing so will either reinforce a current theory or require that it be abandoned.

There are uncertainties about the prevailing climate consensus which require determined efforts to falsify it (see Finding the Truth on Climate Change, 2007). None of the data related to climate change establishes a definite causal relationship between human CO2 emissions, increasing atmospheric CO2 levels and rising temperatures. Correlation is not always causality. And statisticians and data analysts can’t prove causality one way of the other. There were massive changes in the earth’s climate prior to widespread human use of fossil fuels. For example about 12-14,000 years ago something initiated an interglacial period in what is still (perhaps) the current ice age. The British Meteorological Office has suggested the ‘possibility’ of a little ‘ice age’ in Europe in the 2030s. And there are indications of reverse causality. For example NASA’s Dr James Hansen, a prominent advocate of the prevailing climate consensus, argues that over geological time scales rising temperatures have driven increases in atmospheric CO2 levels. And other respectable scientists argue that: (a) there is evidence of reverse causality over much shorter time scales; and (b) there are a large number of other drivers of climate change. Water vapour is ignored as a major factor in driving climate change even though it has the largest greenhouse effect – because it is a mere ‘feedback’ ie levels increased by the real ‘drivers’ of climate change. Perhaps, to some extent, analysts need to treat CO2 as a ‘feedback’ rather than a ‘forcing’.

Such possibilities need to be investigated by providing resources to those who have advanced alternative theories. Unfortunately scientific scepticism in relation to the prevailing climate consensus has been strongly discouraged by (for example) suggesting that: (a) the prevailing climate consensus is necessarily correct because a particular group (eg expert statisticians and data analysts) support it; and (b) that there is something wrong with anyone who suggests otherwise (eg by denigrating them as ‘denialists’). Those tactics are the defining characteristics of ‘political correctness’ which has become a major obstacle to progress in many areas of human endeavour (see The Church of Political Correctness Threatens National Progress).

John Craig

Climate History and the History of Climate Science

Climate History and the History of Climate Science

In response to an email concerning a quite different matter, the present writer's attention was drawn to Professor Matthew England (UNSW) as a reliable source of information about both climate history and the history of climate science.

Email from Professor Matthew England (UNSW) 16/10/16 

Thanks XXXX for the recommendation - what questions do you have?   I'd be very happy to answer them if I can......  


CPDS Reply - 18/2/16

 I did not initially have a specific question – as I was mainly interest to hear XXXX's recommendation about you and to keep that in my mind for the future.

When XXXX mentioned your work I scanned the Internet for references to it. The first that I saw indicated your involvement in public debates about climate science. By way of background my position on this is that we need more than quasi-political debates that involve stating (but not resolving) competing views about climate science. I suspect that firming up the science by providing resources for a formal process to try to falsify mainstream theories (and thus to either strengthen, or to force changes in, them) has been needed since the 1990s when climate change was first recognised to be more than a future possibility.  

 However, as indicated in my email of 16/10/16 below, a question about sea levels did turn up a day or so later about which I would appreciate an opinion.


CPDS Email to XXXX - 16/10/16

Thanks for that suggestion. I certainly keep an eye on what climate, land, soil, and water scientists have to say though I sometimes find reasons to suggest that their specialised world views are a bit too narrow.   For example this morning I had a conversation with a prominent marine scientist about the research that has now started into the effect of climate change (ie the future implications of the 120m or so rise in sea levels at the end of the last ice age). He seemed to be making assumptions that were incompatible with indicators that I had found years ago by noting the work of other specialist (eg in climate, geological and human history).

 Concerns about the effect of climate change on the Great Barrier Reef have apparently given rise to undersea mapping adjacent to the reef which give an indication of what happened last time there was a large climatically induced change in sea levels (ie when ocean levels rose about 120m at the end of the last ice age).  I would appreciate your view about how quickly that sea level rise might have occurred.


 A marine scientist friend I discussed this with had quite a different view of this to the perceptions I have had from other sources. His argument was that the end-of-ice-age sea level rise must have been slow (ie taken about 20,000) years as otherwise the barrier reef would not have survived. He suggested that reef ecosystems can only exist on of existing reefs – and that while coral polyps can establish new coral clumps just establishing one in a new location could take 100 years – and thus that any rises in ocean levels must have been very slow. [My interpretation of what he argued could well be wrong – as coral and reef ecosystems are a mystery to me]. He also believed that the Biblical Great Flood accounts must have reflected local events in Europe rather than a global phenomenon.

The impression that I had previously had was that the rise must have been a lot faster and global. There are (so I understand) stories of a ‘great flood’ in folk histories worldwide that parallel the Biblical account. A rise of (say) 6mm pa over 20,000 years would not have caused anyone to get excited about a ‘great flood’. Also it is my understanding that when surface water penetrates to the base of ice sheets it can cause them to collapse relatively quickly. And the first images that were put out of subsurface areas adjacent to the Great Barrier Reef seems to show an ancient reef 120m down – but nothing to indicate intermediate reefs between that and the current reef. And, if coal polyps can establish new coral clumps that could eventually provide the basis for a reef and reef ecosystem after say 1-2,000 years, would there be any real need for it to be near the old reef? Also I read at one stage (but can’t now locate reference to) indications in coastal areas of NSW of 10-20 rises in sea levels earlier in the earth’s geological history that were believed to have only taken a decade or so.  Needless to say it is a lot easier to get evidence about sea level rises that affected areas now above sea level than about those that are now submerged.

Note added later: In late 2016 a TV presentation ('David Attenborough's Great Barrier Reef') referred to an indigenous group in north Queensland whose traditional practices included dances that commemorated rapid ocean level rises at about the same time as the end of the last ice age (and at the same time that it is believed that the Great Barrier Reef was formed). It was believed that the ocean moved several hundred meter pa onshore over fairly flat terrain. Such a rate of rise would certainly have been seen by those affected as a 'great flood' and probably indicates a rise of (say) 1-2m pa in which case the whole approx 120m rise associated with the end of the ice age might have taken (say) 100-300 years rather than the 20,000 years needed by 6mm pa rises. 

 Your thoughts on this would be valued.

Needless to say if there is a possibility that climate change could induce very fast ocean level rises (eg several-metres-year rather than the prevailing few-mm-per-year assumptions) the whole climate change debate could gain a new public urgency and require a lot more resources to be devoted to understanding what is going on.


Email from Matthew England - 18/8/16

Thanks for the enquiry.   The science I undertake is better profiled in my publications, which I have accessible on my website (see link below).

Those public debates are not a good place to start: while these can be fun for an audience, analysis shows that they just polarise opinion, rather than advancing the dialogue usefully.

In terms of your sea-level questions, the best resource are the IPCC chapters on sea-level rise, and paleoclimate, which are comprehensive:

http://www.ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_Chapter13_FINAL.pdf

http://www.ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_Chapter05_FINAL.pdf

A hint: search for the word "paleo" in the sea-level chapter. And search for the phrase sea level in the paleo chapter.  

CPDS Notes from Perusal of IPCC Analyses:

The 'sea-level' chapter in IPCC report referred to indicators of a 7m sea level rise over 1000-7000 years (ie 7-1mm/year average) while noting the lack of information about rates. Reference was also made to rapid rises during a glacial termination period (ie 10mm / year over centuries or even 40mm / year).

The 'paleo' chapter referred to indicators of sea levels 5-10 above current levels during the last interglacial (ie 129,00 - 116,00 years BP) and levels 20m higher during the Pliocene (3.3-3m years BP). Rises over past few thousand years have been no more than 25cm / century (ie 2.5mm / year). Last glacial termination (14,640-12,850 years BP) saw a sea level rise of about 120m  (ie an average of about 60mm/year). The initial responses of ice sheets to external forcings can be quite fast (ie over 10-1000 years) though long term adaptation takes 10,000-100,000 years. Some adjustments can occur over months. The last glacial melting from 20,000 to 7,000 years BP saw a rise of 130m (ie a 10mm / year average). A 20m rise occurred over 340 years (ie an average of about 60mm / year).

The implication is that the IPCC concludes that the peak rates of sea level rise in geological history have been relatively modest (ie insufficient to have been viewed as a 'great flood') - even though greater than those currently occurring. However it also noted that reliable information about rates of rise are not available and that it is possible for relatively rapid rises to occur over short periods under some circumstances.

Just one point of correction: when you write:-

   "....since the 1990s when climate change was first recognised to be more than a future possibility...."

This is out by around 4-6 decades, depending on how you define recognition. For example, see 1938 in this history of climate change science produced by the American Institute of Physics:   https://www.aip.org/history/climate/timeline.htm 


CPDS Reply - 18/10/16

Thanks for links which I will chase up.

However early in my career (in the early 1970s) I was asked to write a report on climate change for Queensland’s Coordinator General . The dominant view I found at that time seemed to involve expectations of the end of the inter-glacial era and the resurgence of a new ice age. I can’t recall finding any significant material then that talked about expected climate changes in the way that is now normal. The latter may have been suggested in the literature but it did not seem to be the established view.


Email from Matthew England - 18/10/16  

Ironically that ice age idea was pushed more by journalists than scientists!!

In fact as I understand it, the idea was only really captured in a single paper by Steve Schneider (a brilliant and much missed scientist by the way), but it got such high-profile coverage in several magazines etc, that it dominated the public discourse.  Yet if you read over that history of climate science by the AIP, you'll see that most scientists of the day were skeptical about Steve's ice age idea.   Indeed, by the early 1970's we already had the first full coupled climate models pointing to the upcoming warming impacts of GHG's.   

So, unfortunately, you might have been looking in the wrong sources for your climate information.    See the attached quotes from a report that a US body prepared for president Jimmy Carter.   The message there was formed from a review of available science in 1979, and I think you'll agree the message is very clear about the problem with carbon emissions......


CPDS Reply - 18/10/16

Fair enough. Leading scientists may well have held views on the GHG issue comparable with the current mainstream in the late 1970s. They would not have been the sources I was reviewing.

However there did not seem to me to be any public understanding that climate change due to GHGs might be a real risk (and thus that it might be necessary to ‘do something’ about it) until the late 1980s / early 1990s. I have found a similar gap between expert and public understanding in many fields – and that expert views are often being challenged by something else by the time they have become publically / politically accepted.


Email from Matthew England - 18/18/18

Thanks John, and I think you're right on that.

After all, the UNFCCC Article 2 was only ratified in 1992 I think.  In contrast, the scientific statements can be traced to the 1970s.  So it did take ~15-20 years for any significant international (political) statement on this.

Well spotted.   Apologies too if my emails ever sound terse: We get lots of questions and enquiries and it's very difficult to respond to everything.  

Climate Science is Not Set in Concrete

Climate Science is Not Set in Concrete - email sent 9/11/16

John Birmingham
c/- Editor Brisbane Times

Avoiding Scientific Scepticism: The Main Tactic of the Prevailing Climate Consensus may be of interest re your article Senator Roberts beats the science out of CSIRO's climate findings, Brisbane Times, 7/11/16. There is a case for devoting resources to checking whether current mainstream views about climate change and its relationship with human CO2 emissions are as solid as your article presumed.

In relation to Senator Roberts' observations about warnings of ‘global freezing’ in the 1970s, recent comments on that thesis are outlined in Climate History and the History of Climate Science. The latter also points to constant changes in scientific views as prevailing theories are challenged by others and by new information. And what is publicly-accepted as ‘climate science’ runs some (say) 15-20 years behind leading scientific ideas. As in many others areas, presuming that that currently publicly / politically accepted ideas are the final word (which your article seems to do in relation to climate science without actually studying what leading edge scientists are suggesting) is unwise. Reputable scientists are still challenging scientists’ consensus and thus laying the basis for a new (and perhaps different) publicly / politically accepted view of climate science in 15-20 years.

Challenging Senator Roberts view that there is something wrong with publicly-accepted interpretations of climate science, requires doing more than claiming that his case is based on prawns, dolphins and fish fingers.

John Craig

Scientific Debate on Climate Change

Scientific Debate on Climate Change - email sent 3/12/16

Peter Ellerton,
University of Queensland

Re: Whose word should you respect in any debate on science?, The Conversation, 1/12/16

I have to submit that there are weaknesses in your article’s attempt to argue that anthropogenic global warning (AGW) theory can be accepted as ‘true’ because reputable scientific societies say that it is (ie that recent changes in the earth’s climate are more-or-less solely due to human emissions of various ‘greenhouse’ gases).

My Interpretation of your article: The motto of Britain’s Royal Society (the world’s oldest scientific society) is ‘take nobody’s word for it’. This rejects authority as a source of truth – and requires experiment and engagement with the natural world to discover truth. Deniers of climate science (eg Senator Malcolm Roberts) use this in attempts to refute global warming and AGW (ie that warming is the result of human activity). This allows them to reject the overwhelming view of science organisations that AGW is a reality. The Royal Society both speaks of not listening to authority and endorses AGW. The Royal Society was formed in 1660 after about 1000 years of near absolute church authority – including general acceptance of Aristotelian natural philosophy. Rebellion against this authority celebrated freedom to put scientific exploration above church authority. The authority that the Royal Society referred to was non-scientific authority. Modern science is now much more complex than it was then – and it is beyond individuals to reach conclusions. Teams of scientists from different disciplines must cooperate. Appeals to authority are seen to be a fallacy of reasoning – but this only applies where false authorities are involved. Appeals to appropriate authorities are valid. It is wrong to suggest that we should not listen to the collective wisdom of scientists. Scientific societies were often involved in transmitting expert advice to governments in the 17-18th centuries. Deniers of climate science continue insist on empirical evidence while simultaneously rejecting it.

In logic, appeals to authority are invalid as a method of ‘proving’ a conclusion – no matter how august the authority. This does not mean that a consensus of scientists who have studied an issue is not well worth listening to – merely that this does this does not ‘prove’ that what they are saying is truth. Recognition of the limits to what can be known though science (eg in terms of the logical invalidity of induction) has long been a major focus of the philosophy of science. And there are other apparent limits to the scientific method which seem to be emerging. For example it has recently been plausibly suggested that up to half the contents of scientific literature may be untrue because of the difficulties that now exist in reaching reliable conclusions and an obsession with pursuing fashionable ideas.

The philosophy of science was expanded in the early 1960s by recognition of the phenomenon of ‘paradigm shifts’ ( ie replacing the core assumptions in a field of knowledge with other core assumptions). Paradigm shifts (eg the 17th century shift from 5th century Aristotelian natural philosophy to an emphasis on 'scientific' methods that your article referred to) may take a long time (eg not to occur until the significant advocates of an established paradigm die).

In considering climate change, there might now be a need for a ‘paradigm shift’ to take account of non-AGW factors as somewhat or very significant drivers of what has recently been happening to the earth’s climate - either counteracting or amplifying (and thus perhaps being mistakenly treated as) AGW effects. There is nothing new about climate change in the earth’s history – and until very recently AGW was clearly not involved in driving change. Scientific research in recent decades has focused on finding evidence of AGW since (say) the industrial revolution. This will not adequately identify the ongoing climate effects of non-AGW factors (see Finding the Truth on Climate Change). The indicators of the limits to mainstream climate change theories that the latter referred to do not ‘prove’ that AGW has not been the main recent influence on the earth’s climate. However they suggest that mainstream AGW theories might be overly simplistic. It has thus probably been necessary since the late 1990s to focus significant scientific resources on investigating non-AGW influences on the earth’s climate. This has not been done. Calling anyone who questions the absolute ‘truth’ of AGW theories names (eg ‘deniers’) does nothing to contribute to resolving such uncertainties.

There are indicators that there might be a need for significant paradigm shifts in other areas (eg economics) in which governments have been guided by established expert opinion – see Problems with a 'Post-truth' World. The latter also mentioned the possibility that a related paradigm shift in the philosophy of science might be needed (eg to recognise the limits of what can be learned through the scientific method). Science seeks to identify deterministic laws and using such laws to predict what will happen is always limited by an inability to take account of influences from outside whatever system is being studied – eg when evolution occurs).

I would be interested in your response to my speculations

John Craig