Summary for policymakers on climate change impacts, vulnerability, and adaptation, based on the IPCC Fifth Assessment Report.
As part of the Working Group II (WGII) contribution to the fifth assessment report of the Intergovernmental Panel on Climate Change, this summary for policymakers focuses on recent work assessing climate change impacts, vulnerability, and adaptation. Compared to previous WGII reports, this assessment considers a substantially larger knowledge base of relevant scientific, technical, and socioeconomic literature.
The summary opens by discussing the context of the assessment, an overview of some of the terminology, and the use of certainty levels when communicating findings. Following this, the summary discusses observed impacts, vulnerabilities, and adaptation actions, before looking at future risks and opportunities for adaptation. This includes key risks across sectors and regions, and the respective potential for adaptation. Next, the summary provides a number of principles for effective adaptation:
Adaptation is context-specific, with no single approach for reducing risks appropriate across all settings.
Adaptation planning and implementation can be enhanced through complementary actions across all levels, from individuals to governments.
A first-step towards adaptation is reducing vulnerability and exposure to present climate variability.
Adaptation actions at all levels of governance are contingent on different societal values, objectives, and risk-perception; recognising this plurality of contexts benefits decision-making processes.
Decision support is most effective when it is sensitive to context and the diversity of decision types, processes, and constituencies.
Existing and emerging economic instruments can foster adaptation by providing incentives for anticipating and reducing impacts.
Constraints such as limited financial and human resources, limited integration and coordination, projected uncertainties, and competing values can interact to impede adaptation planning and implementation.
Poor planning that is too short-term in thinking can result in unforeseen maladaptive consequences.
Significant trade-offs, co-benefits, and synergies exist between mitigation and adaptation, with interactions occurring both within and across regions.
Finally, the summary outlines some approaches for climate-resilient pathways and transformation, that is, sustainable development trajectories that combine mitigation and adaptation to reduce climate change and it impacts. Fundamentally, the prospects for sustainable development pathways are very much dependent on what the world accomplishes with climate change mitigation, both in terms of scale required and the time-spans available. Opportunities for effective adaptation measures are therefore decreasing over time, increasing the risk of some areas exceeding adaptation limits. Transformational changes in economic, social, technological and political decisions and actions can enable climate-resilient pathways, and can be encouraged through iterative, deliberative approaches and innovation.