Editing IPCC:AR6/WGI/Chapter-11 (section)

=== 11.1.1 Scope of the Chapter ===

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This chapter provides assessments of changes in weather and climate extremes (collectively referred to as extremes) framed in terms of the relevance to the Working Group II (WGII) assessment. It assesses observed changes in extremes, their attribution to causes, and future projections, at three global warming levels: 1.5°C, 2°C, and 4°C. This chapter is also one of the four ‘regional chapters’ of the WGI Report (along with Chapters 10 and 12 and the Atlas). Consequently, while it encompasses assessments of changes in extremes at global and continental scales to provide a large-scale context, it also addresses changes in extremes at regional scales.

Extremes are climatic impact-drivers (Annex VII: Glossary, see [[IPCC:Wg1:Chapter:Chapter-12|Chapter 12]] for a comprehensive assessment). The IPCC risk framework (Chapter 1) articulates clearly that the exposure and vulnerability to climatic impact-drivers, such as extremes, modulate the risk of adverse impacts of these drivers, and that adaptation which reduces exposure and vulnerability will increase resilience, resulting in a reduction in impacts. Nonetheless, changes in extremes lead to changes in impacts as a direct consequence of changes in their magnitude and frequency, and also through their influence on exposure and resilience.

The Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation (referred as the SREX report, IPCC, 2012) provided a comprehensive assessment on changes in extremes and how exposure and vulnerability to extremes determine the impacts and likelihood of disasters. [[IPCC:Wg1:Chapter:Chapter-3|Chapter 3]] of that report ( [[#Seneviratne--2012|Seneviratne et al., 2012]] , hereafter also referred to as SREX Chapter 3) assessed physical aspects of extremes, and laid a foundation for the follow-up IPCC assessments. Several chapters of the IPCC Fifth Assessment Report (AR5) (IPCC, 2013) addressed climate extremes with respect to observed changes ( [[#Hartmann--2013|Hartmann et al., 2013]] ), model evaluation ( [[#Flato--2013|Flato et al., 2013]] ), attribution ( [[#Bindoff--2013|Bindoff et al., 2013]] ), and projected long-term changes ( [[#Collins--2013|Collins et al., 2013]] ). Assessments were also provided in the IPCC Special Report on Global Warming of 1.5°C (SR1.5) ( [[#IPCC--2018|IPCC, 2018]] ; [[#Hoegh-Guldberg--2018|Hoegh-Guldberg et al., 2018]] ), on climate change and land (SRCCL; ( [[#IPCC--2019a|IPCC, 2019a]] ), and on oceans and the cryosphere (SROCC; [[#IPCC--2019b|IPCC, 2019b]] ). These assessments are the starting point for the present assessment.

This chapter is structured as follows (Figure 11.1): This section (11.1) provides the general framing and introduction to the chapter, highlighting key aspects that underlie the confidence and uncertainty in the assessment of changes in extremes, and introducing some main elements of the chapter. To provide readers with a quick overview of past and future changes in extremes, a synthesis of global-scale assessments for different types of extremes is included at the end of this section (Tables 11.1 and 11.2). [[#11.2|Section 11.2]] introduces methodological aspects of research on climate extremes. Sections 11.3 to 11.7 assess past changes and their attribution to causes, and projected future changes in extremes, for different types of extremes, including temperature extremes, heavy precipitation and pluvial floods, river floods, droughts, and storms, in separate sections. [[#11.8|Section 11.8]] addresses compound events. [[#11.9|Section 11.9]] summarizes regional assessments of changes in temperature extremes, in precipitation extremes and in droughts by continents in tables. The chapter also includes several boxes and FAQs on more specific topics.

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[[File:559628200b7daeef7fb327d7ea06b439 IPCC_AR6_WGI_Figure_11_1.png]]

'''Figure 11.1 |''' '''Visual guide to Chapter 11.'''

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