Perceptions of carbon dioxide reductions and future warming among climate experts

The Intergovernmental Panel on Climate Change (IPCC) uses emissions scenarios to examine a range of future climate outcomes, but does not assign probabilities to individual scenarios. However, the IPCC authors have their own views on the likelihood of different climate outcomes, which are important to understand because the authors have expertise and considerable influence. Here we present the results of a survey of 211 IPCC authors on the likelihood of four key climate outcomes. We find that most authors are skeptical that warming will be limited to the Paris targets well below 2°C, but are more optimistic that net zero CO ₂ will be reached during the second half of this century. When asked about their peers' beliefs, the authors' responses showed strong correlations between personal and peer beliefs, suggesting that participants with extreme beliefs perceive their own estimates to be closer to the community average than they actually are. (Seth Wynes, Steven J. Davis, H. Damon Matthews, more at nature.com)