Is the IPCC a scientific or political body? How good is its scientific advice?

The body to which most governments turn for advice on climate change is the IPCC. Formed in 1988 by the United Nations and the World Meteorological Organization, the IPCC has now issued three substantial statements, the First (1990), Second (1995) and Third (2001) Assessment Reports, each of which incorporates the research and opinions of many hundreds of qualified scientists. The reports are detailed and compendious, and each is therefore accompanied by a short chapter termed a Summary for Policymakers (SPM) which is designed for political application. Many distinguished scientists refuse to participate in the IPCC process, and others have resigned from it, because in the end the advice that the panel provides to governments is political and not scientific (Gray, 2002; see also summary at NZ Climate Science Coalition, 2005, Appendix B).

Despite the expenditure of at least $50 billion on climate research since 1990, the science arguments for a dangerous human influence on global warming have, if anything, become weaker since the establishment of the IPCC. Yet the rhetoric of alarm has been successively ramped up, from “the observed (20th century temperature) increase could be largely due to ... natural variability” (IPCC, 1990); to “the balance of the evidence suggests a discernible human influence on climate” (IPCC, 1995):  to “there is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities” (IPCC, 2001); to it is “90% probable” that the recent warming is “due to the observed increase in anthropogenic greenhouse gas concentrations” (IPCC, 2007). What can the evidence be for these increasingly dramatic warnings?

The IPCC advances three main categories of argument for a dangerous human influence on climate. The first is that over the last 100 years global average temperature increased by about 0.74⁰ C, which indeed it did if you accept (against the odds) that the surface thermometer record used by the IPCC is accurate (cf. Fig. 6). More reliably, historical records and many geological data sets show that warming has indeed occurred since the intense cold periods of the Little Ice Age in the 14th, 17th and 19th centuries (e.g. Lamb, 1977). The part of this temperature recovery which occurred in the 20th century is the much famed “global warming”, alleged to have been caused by the accumulation of human-sourced carbon dioxide in the atmosphere. However, the high quality MSU satellite data discussed earlier signal not only the absence of substantial human-induced warming by recording similar temperatures in 1980 and 2006 (Fig. 9), but also provide an empirical test of the greenhouse hypothesis as understood by the public - a test that the hypothesis fails.

The second category of alarmist argument rests upon circumstantial evidence. It is epitomized by Al Gore’s film “An Inconvenient Truth”, which claims that human greenhouse emissions are causing accelerated melting of icecaps, dangerous increases in the rate of sea-level rise, increases in the frequency and intensity of droughts or catastrophic storms, and enhanced rates of biodiversity loss. Every such circumstantial argument ignores two basic facts. The first is that all environmental phenomena fluctuate in their rate, frequency or intensity as part of the normal workings of our dynamic planet. The second, which follows, is that whether a particular short-term change over, say, the early 21st century has any human causation can only be assessed when all the causes of natural environmental change are fully understood. Many different fields of study are involved and all are the subject of intensive ongoing research. From this research emerges one implacable fact. It is that - despite the weekly promulgation of new alarmist headlines in the media - in no case yet has any climate-sensitive environmental parameter been shown to be changing at a rate that exceeds its historic natural rate of change, let alone in a way that can be unequivocally associated with human causation. For example, despite numerous attempts to link an increase in the intensity or number of hurricanes to late 20^th century warming, convincing statistical evidence is absent (Kossin et al., 2007). Similarly, the rates of sea-level rise now predicted by the IPCC (IPCC, 2007) fall entirely within the expected natural rates of rise that have been documented from tide gauge records over the last 200 years (IPCC, 2001). And similarly again, both the Greenland and Antarctic ice sheets are close to mass balance (Zwally et al., 2005), and the interiors of both have cooled over recent decades.

The third line of IPCC argument, and the least convincing of all, is the use of computer calculations to assess the likely future course of climate. Many billions of dollars have been expended by major climate research groups on honing complex GCMs of the ocean and atmosphere. The models are a great intellectual accomplishment, and their application helps us to understand environmental and climatic change in many different ways. However, none of these models has been validated, in the sense of having passed successful prediction tests over the required range of circumstances, and their accuracy is therefore unknown. As Hendrik Tennekes remarked recently, “a (GCM) prediction fifty or a hundred years into the future is an idle gesture”. That the IPCC relies so heavily upon complex GCM-generated scenarios as the basis for its climate alarmism is in point of fact alarming in its own right; it also reflects the absence of any strong empirical evidence for human-caused climate change, as outlined earlier.

Special pleadings aside, therefore, the evidence for dangerous human-caused global warming forced by human carbon dioxide emissions is extremely weak. That the satellite temperature record shows no substantial warming since 1978, and that even the ground-based thermometer statistic records no warming since 1998, indicates that a key line of circumstantial evidence for human-caused change (the parallel rise in the late 20th century of both atmospheric carbon dioxide and surface temperature) is now negated.

Against this background, in February this year the IPCC released the SPM for its 4th (Science) Assessement Report. The new summary (capriciously released two months before the report to which it refers) reduces earlier estimates of the expected magnitude of sea-level  and temperature rise, but does not ameliorate the IPCC’s rhetoric. The summary also continues the regrettable practice of allocating arbitrary numerical probability estimates to the causes and risks of future damaging climate change (IPCC, 2005). In the present state of knowledge, no scientist - IPCC acolyte or otherwise - can justify the statement that “most of the observed increase in globally averaged temperature since the mid-20th century is very likely (= 90% probable) due to the observed increase in anthropogenic greenhouse gas concentrations” (IPCC, 2007).

Conclusions

It is plain that the press have failed in their role as public “watchdog” against the specious pleadings of contemporary climate alarmists; indeed, the media itself is a self-interested party to the debate (cf. Carter, 2006a, b). And, returning to our starting point, political leaders such as British Prime Minister Tony Blair are misadvised both by this press bias and also because they have mistakenly trusted the IPCC to provide dispassionate scientific advice about global warming. In reality, with the complete discrediting of the “hockey stick” curve of recent temperature change (McIntyre and McKitrick, 2003, 2005; Wegman et al., 2006) that was the icon of the 2001 IPCC report, the IPCC case for dangerous human-caused warming now rests only on ambiguous anecdotal evidence, unvalidated computer models and misleading attribution studies (IPCC, 2007). Appearing to concede this, and providing a truly frightening insight into the “scientific” attitudes of the professional climate science research community, UK Tyndall Centre Director, Professor Mike Hulme, wrote recently in The Guardian (March 14, 2007) that:

"Self-evidently dangerous climate change will not emerge from a normal scientific process of truth seeking, although science will gain some insights into the question if it recognises the socially contingent dimensions of a post-normal science. But to proffer such insights, scientists - and politicians - must trade (normal) truth for influence. If scientists want to remain listened to, to bear influence on policy, they must recognise the social limits of their truth seeking and reveal fully the values and beliefs they bring to their scientific activity."

Climate change as a natural hazard is as much a geological as it is a meteorological issue. It therefore needs to be managed in the same way as other geohazards, i.e. by monitoring for the onset of dangerous events and having in place an emergency response plan to deal with any that eventuate. One meritorious example of this is New Zealand’s geohazard network, termed GeoNet, which provides civil defense authorities and the public with accurate, evidence-based information regarding hazards such as earthquakes, volcanic eruptions, tsunamis and floods. Though climate change has so far not been included in GeoNet planning, it differs from the hazards that are covered only in the extended decadal time-scale over which a deleterious trend may occur; GeoNet already deals with the short term extreme weather events that are associated with New Zealand’s mid-latitude, maritime location. Climate response plans also need to be able to cope with the type of sudden “climate” events that are known both in human (1816, the “year without a summer”; Harington, 1992) and geological history (sharp warmings over a few years to decades, followed by coolings, associated with 1470 year-period Dansgaard-Oeschger events; e.g. Burns et al., 2003).

Those planning national climate policies must abandon the alarmist IPCC view of climate change, and the illusory goal of climate mitigation. Instead, plans are needed to identify when a dangerous weather or climate event is imminent, or has started. At the same time, research spending should be reallocated from greenhouse and computer modelling studies and put towards the study of natural climate rhymns and the development of predictive tools for longer term climatic coolings and warmings. Natural climate change being a real and undisputed hazard it is certainly something that governments should prepare for, in the same way that they plan for other natural disasters. Of the two future climate possibilities, dangerous warming or dangerous cooling, the evidence suggests that cooling will be the more damaging; arguably, it is also the most imminent threat. First, because there has been no measurable warming of global average temperatures since 1998; second, because this lack of warming coincides with empirical computer predictions for cooling and evidence for decreasing solar activity in the first few decades of the 21^st century; and third because the current warm interglacial period has already lasted 10,000 years and will inevitably be followed by a glaciation.

Whether human activities have a measurable global influence on natural climate trends has yet to be demonstrated. And, depending upon the balance of the mechanisms (e.g. aerosols versus greenhouse gases), the overall human effect could in the end turn out to be one of either warming or cooling (cf. IPCC, 2007, Fig. SPM-2). That we don't yet know which is, of course, a reflection of the small size of the human signal and of the fact that it is deeply buried in the noise of the natural climate system. The current human-caused global warming hysteria - promulgated by the media - is especially dangerous because it is causing governments to neglect the much more real (though long term) dangers of natural climate change. Even worse, it is causing profound damage to the use of science as an impartial arbiter in public affairs.

This paper started with an alarmist quotation about global warming from British Prime Minister Tony Blair. It seems appropriate to end it, therefore, by recounting the advice that President Vaclav Klaus of the Czech Republic recently (March, 2007) delivered to the US Congress Committee on Energy and Commerce:

“As someone who lived under communism for most of my life I feel obliged to say that the biggest threat to freedom, democracy, the market economy and prosperity at the beginning of the 21^st century is not communism or its various softer variants. Communism (has been) replaced by the threat of ambitious environmentalism  .…. The environmentalists consider their ideas and arguments to be an undisputable truth and use sophisticated methods of media manipulation and PR campaigns to exert pressure on policymakers to achieve their goals. Their argumentation is based on the spreading of fear and panic by declaring the future of the world to be under serious threat. In such an atmosphere they continue pushing policymakers to adopt illiberal measures, impose arbitrary limits, regulations, prohibitions, and restrictions on everyday human activities and make people subject to omnipotent bureaucratic decision-making. … Man-made climate change has become one of the most dangerous arguments aimed at distorting human efforts and public policies in the whole world”.

Acknowledgements

I thank Drs. Basil Beamish and Gerrit van der Lingen for providing constructive critical comments on the draft of this paper, Willis Eschenbach for providing the graphs for Fig. 4, and the Australian Research Council for financial  support under grant DP 0344080. It is also appropriate that I acknowledge the many colleagues who participate in the email chat groups Climate Sceptics (moderated for many years by Timo Hameranta, and now by David Wojick) and New Zealand Climate Science Coalition (moderated by Terry Dunleavy). Chat group members are too numerous to name individually, but I thank them all for the questing, critical and informative nature of their postings on many diverse topics, for it has greatly expanded my knowledge and understanding of the vexed issue of global climate change.  – Bob Carter