Climate change prediction: Erring on the side of least drama?

Thermal Science, 2015

Climate change is a complex and multi-facetted phenomenon, interpreted by an extensive body of interdisciplinary science. Although a great deal is known about the climate system, an enormous amount of uncertainty remains. Since uncertainty is usually equated with ignorance, this fact feeds scepticism on man-induced impacts on the global climate and links climate change with natural causes only. A broader concept of climate change science is presented by focusing on both early and modern scientific foundations of climate models and specific types of uncertainty usually encountered when formulating quantitative assessments of risks due to climate change. Major controversial issues of such risks and their origin is addressed with paticular attention paid to the widespread criticism for inconsistency of the reports of the Intergovernmental Panel on Climate Change, based on the assumptions found not always justified by the real scientific methods. Major inconsistencies and misleading arguments on the climate change are also discussed.

Human-induced climate change is an existential risk to human civilisation: an adverse outcome that would either annihilate intelligent life or permanently and drastically curtail its potential. Special precautions that go well beyond conventional risk management practice are required if the “fat tails” — the increased likelihood of very large impacts — are to be adequately dealt with. The potential consequences of these lower-probability, but higher-impact events would be devastating for human societies. The bulk of climate research has tended to underplay these risks, and exhibited a preference for conservative projections and scholarly reticence, albeit increasing numbers of scientists have spoken out in recent years on the dangers of such an approach. Climate policymaking and the public narrative are significantly informed by the important work of the Intergovernmental Panel on Climate Change (IPCC). However, IPCC reports also tend toward reticence and caution, erring on the side of “least drama”, and downplaying more extreme and more damaging outcomes. Whilst this has been understandable historically, given the pressure exerted upon the IPCC by political and vested interests, it is now becoming dangerously misleading, given the acceleration of climate impacts globally. What were lower-probability, higher-impact events are now becoming more likely. This is a particular concern with potential climatic “tipping points” — passing critical thresholds which result in step changes in the system — such as the polar ice sheets (and hence sea levels), and permafrost and other carbon stores, where the impacts of global warming are non-linear and difficult to model at present. Under-reporting on these issues contributes to the “failure of imagination” that is occurring today in our understanding of, and response to, climate change. If climate policymaking is to be soundly based, a reframing of scientific research within an existential risk-management framework is now urgently required. This must be taken up not just in the work of the IPCC, but also in the UN Framework Convention on Climate Change negotiations if we are to address the real climate challenge. Current processes will not deliver either the speed or the extent of change required.

In 2007, the Intergovernmental Panel on Climate Change’s Working Group One, a panel of experts established by the World Meteorological Organization and the United Nations Environment Programme, issued its Fourth Assessment Report. The Report included predictions of dramatic increases in average world temperatures over the next 92 years and serious harm resulting from the predicted temperature increases. Using forecasting principles as our guide we asked: Are these forecasts a good basis for developing public policy? Our answer is “no”. To provide forecasts of climate change that are useful for policy-making, one would need to forecast (1) global temperature, (2) the effects of any temperature changes, and (3) the effects of feasible alternative policies. Proper forecasts of all three are necessary for rational policy making. The IPCC WG1 Report was regarded as providing the most credible long-term forecasts of global average temperatures by 31 of the 51 scientists and others involved in forecasting climate change who responded to our survey. We found no references in the 1056-page Report to the primary sources of information on forecasting methods despite the fact these are conveniently available in books, articles, and websites. We audited the forecasting processes described in Chapter 8 of the IPCC’s WG1 Report to assess the extent to which they complied with forecasting principles. We found enough information to make judgments on 89 out of a total of 140 forecasting principles. The forecasting procedures that were described violated 72 principles. Many of the violations were, by themselves, critical. The forecasts in the Report were not the outcome of scientific procedures. In effect, they were the opinions of scientists transformed by mathematics and obscured by complex writing. Research on forecasting has shown that experts’ predictions are not useful in situations involving uncertainly and complexity. We have been unable to identify any scientific forecasts of global warming. Claims that the Earth will get warmer have no more credence than saying that it will get colder.

Social Studies of Science, 2012

How and why did the scientific consensus about sea level rise due to the disintegration of the West Antarctic Ice Sheet (WAIS), expressed in the third Intergovernmental Panel on Climate Change (IPCC) assessment, disintegrate on the road to the fourth? Using ethnographic interviews and analysis of IPCC documents, we trace the abrupt disintegration of the WAIS consensus. First, we provide a brief historical overview of scientific assessments of the WAIS. Second, we provide a detailed case study of the decision not to provide a WAIS prediction in the Fourth Assessment Report. Third, we discuss the implications of this outcome for the general issue of scientists and policymakers working in assessment organizations to make projections. IPCC authors were less certain about potential WAIS futures than in previous assessment reports in part because of new information, but also because of the outcome of cultural processes within the IPCC, including how people were selected for and worked tog...

Nature Climate Change, 2014

There is a gap between the current role of the climate science community and the needs of society. Closing this gap represents a necessary but insufficient step towards improved public discourse and more constructive policy formulation on climate change. How should climate scientists balance their efforts between investigating the climate system and engaging with policy-makers and the public? When engaging, should they merely aim to inform policy, or should they advocate specific actions? In a newly published study 1 we argue that these questions are unresolved, and that there is a gap between the role of the climate science community and the needs of society. The implications of climate science merit widespread constructive and thoughtful discussion. Yet the public discourse is commonly fraught with contention, and climate scientists often find themselves on the receiving end of emotionally-charged reactions to their work. To turn this situation around, we encourage the community to reconsider its professional practices, skills and norms, and to adjust its training and development activities accordingly.

This report, published in March 2014, shows that the best observational evidence indicates our climate is considerably less sensitive to greenhouse gases than climate models are estimating. The clues for this and the relevant scientific papers are all referred to in the recently published Fifth Assessment report (AR5) of the Intergovernmental Panel on Climate Change (IPCC). However, this important conclusion was not drawn in the full IPCC report – it is only mentioned as a possibility – and is ignored in the IPCC’s Summary for Policymakers (SPM).

In recent times, there have been numerous attacks on the global warming thesis and its effects on the climate advocated by the UN Intergovernmental Panel on Climate Change (IPCC) questioning its reports produced with the participation of 2,500 scientists from 131 countries, gathering observations, conclusions, forecasts and recommendations from several thousand climate scientists from around the world. What we are witnessing today is a veritable war of the media and the US government against the issue of climate change and its relationship to predatory human activities such as the emission of greenhouse gases. The paradigm that attributes to man the greatest cause of climate change is being confronted by the skeptics who consider the paradigm that attributes their greater responsibility to natural causes.

Science, 2004

Theoretical and Applied Climatology, 2015

Among papers stating a position on anthropogenic global warming (AGW), 97 % endorse AGW. What is happening with the 2 % of papers that reject AGW? We examine a selection of papers rejecting AGW. An analytical tool has been developed to replicate and test the results and methods used in these studies; our replication reveals a number of methodological flaws, and a pattern of common mistakes emerges that is not visible when looking at single isolated cases. Thus, real-life scientific disputes in some cases can be resolved, and we can learn from mistakes. A common denominator seems to be missing contextual information or ignoring information that does not fit the conclusions, be it other relevant work or related geophysical data. In many cases, shortcomings are due to insufficient model evaluation, leading to results that are not universally valid but rather are an artifact of a particular experimental setup. Other typical weaknesses include false dichotomies, inappropriate statistical methods, or basing conclusions on misconceived or incomplete physics. We also argue that science is never settled and that both mainstream and contrarian papers must be subject to sustained scrutiny. The merit of replication is highlighted and we discuss how the quality of the scientific literature may benefit from replication.