Improving Communication About Potentially Catastrophic Risks of Climate Change

Abstract:

Scientific assessments of future climate change tend to focus on central estimates and may understate or ignore the significance of low probability outcomes that may have extremely severe consequences. This relative neglect of tail risks is partly a result of traditions in prediction and forecasting, and conservatism about phenomena for which few data and information exist.

The misinterpretation of such scientific assessments can have adverse results. Even though the central estimates of high emissions scenarios present obvious dangers, the tails of lower emissions scenarios still contain very serious risks which may be overlooked by policy-makers. Economic analyses may omit the possibility of catastrophic impacts, leading to substantial under-estimates of damage caused by climate change.

So how do we avoid these shortcomings and achieve more effective communication about the risks of climate change?

The scientific assessments of climate change differ in significant ways from the formal risk assessment methods successfully employed in other fields. We outline a ‘good practice’ approach to the identification, assessment and communication of potentially catastrophic risks based on examples from sectors such as civil engineering, national security and insurance.

We illustrate how this ‘good practice’ approach could be applied to provide a better presentation of some catastrophic tail risks that are outlined in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. The risks we consider include the possibility of ‘extreme’ rises in temperature and sea level lying outside the central projections described in the report, and the plausibility of significant releases of methane from the thawing of permafrost.

Using these illustrations, we examine how scientific researchers can improve their communication about climate change to assist decision-making, and how policy-makers and politicians might respond differently to alternative presentations of information about the tail risks.