Recently Released: IPCC 5th Annual Report Section on Impacts, Adaptation and Vulnerability

By Liz Allen

This October the 40th Session of Intergovernmental Panel on Climate Change (IPCC) will meet to approve the synthesized 5th Assessment Report (AR5) on global climate change. The AR5 is based on three working group contributions: Physical Science Basis (WG1), Impacts, Adaptation and Vulnerability (WG2) and Mitigation of Climate Change (WG3). The sections from each working group are already drafted and available online.

In late March members of WG2 met in Yokohama, Japan and officially approved the Impacts Adaptation and Vulnerability Summary for Policymakers. The team that contributed to the Impacts Adaptation and Vulnerability report included 243 lead authors and 66 review authors from 70 countries.

The overarching goals of the Impacts, Adaptation and Vulnerability section are to characterize observed climate change impacts and vulnerability, examine risks and potential benefits across sectors and regions, and identify where management and policy choices may reduce risks through mitigation and adaptation. A key change between this new report (AR5) and the last report (AR4) is the development of new Representative Concentration Pathway (RCP) scenarios to explore in more depth how social and environmental futures may unfold under various drivers and test how mitigation interventions may play out. Another new aspect of the AR5 is the treatment of uncertainty. Findings now are presented with specifically defined, standardized language that communicates the strength of scientific understanding, including uncertainties and areas of disagreement.

The IPCC Impacts, Adaptation and Vulnerability working group drew on a vast body of published literature from the last decade to increase the robustness of interpretations about the likelihood of future change as a basis for timely policy recommendations. So, while projections of global climate change and its implications for agricultural productivity and streamflow, for example, have not changed dramatically since previous IPCC reports, there has been a deliberate shift in the rhetoric used to describe likely impacts and what constitutes appropriate policy responses. This shift in language is, at least in part, a response to social scientists’ and communication scholars’ recommendations for the climate science research community to clearly and unequivocally communicate dire possible future circumstances indicated by scientific evidence. Connected to this, there is increasing demand for scientists to take an ethical stance regarding society’s responsibility to act in response to climate change risks.

It remains to be seen whether the IPCC’s new more deliberate language around uncertainty and risk will be effective in promoting a societal response. In my interactions, I’ve learned that while most scientists want their research to be understood and used for the betterment of society, many are still very uncomfortable with blurring the line between research and public communication or advocacy. Some fear that a move toward assessments and recommendations that include more value-laden language could hinder, rather than promote effective policy action by appearing to take a partisan stance.