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

=== Atlas.1.2 Context and Framing ===

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Information on global and regional climate change in the form of maps, tables, graphs and infographics has always been a key output of IPCC reports. With the consensus that climate has changed and will continue to do so, policymakers are focusing more on understanding its implications, which often requires an increase in regional and temporal details of observed and future climate. The WGI contribution to AR5 included globally comprehensive coverage of land regions and some oceanic regions in the Atlas of Global and Regional Climate Projections ( [[#IPCC--2013a|IPCC, 2013a]] ), focusing on projected changes in temperature and precipitation. In the WGII contribution, Chapter 21, Regional Context ( [[#Hewitson--2014|Hewitson et al., 2014]] ) included continental-scale maps of observed and future temperature and precipitation changes, sub-continental changes in high percentiles of daily temperature and precipitation, and a table of changes in extremes over sub-continental regions (updating an assessment in the Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation; SREX). However, there was only limited coordination between these two contributions despite the largely common data sources and their relevance across the two working groups and to wider communities of climate change-related policy and practice. This resulted in inefficiencies and the potential for confusing or inconsistent information. The Atlas, with its links with other WGI/II/III chapters, has been designed to help address this.

Given the aims of the Atlas, there are several important factors to consider. There is a clear requirement for climate change information over a wide range of ‘regions’, and classes thereof, and temporal scales. There is also often the need for integrated information relevant for policy, practice and awareness raising. However, most other chapters in WGI are disciplinary, focusing on specific processes in the climate system or on its past or future behaviour, and have limited space to be spatially and temporally comprehensive. The Atlas provides an opportunity to facilitate this integration and exploration of information.

Developing this information often requires a broad range of data sources (various observations, global and regionally downscaled baselines and projections) to be analysed and combined and, where appropriate, reconciled. This is a topic which is assessed from a methodological perspective in [[IPCC:Wg1:Chapter:Chapter-10|Chapter 10]] using a limited set of examples (see also Cross-Chapter Box 10.3). The Atlas then builds on this work with a more comprehensive treatment of the available results, largely (but not exclusively) based on CMIP5, CMIP6 and CORDEX, to provide wider coverage and to further demonstrate techniques and issues. These multiple lines of evidence are integrated in the Interactive Atlas, a new AR6 WGI product described in [[#Atlas.2|Atlas.2]] allowing for flexible spatial and temporal analysis of this information with a predefined granularity (e.g., flexible seasons, regions and baselines, and future periods of analysis including time slices and warming levels).

Generating information relevant to policy or practice requires understanding the context of the systems that they focus on. In addition to the hazards these systems face, their vulnerability and exposure, and the related socio-economic and other physical drivers, also need to be understood. To ensure this relevance, the Atlas is informed by the assessments in [[IPCC:Wg1:Chapter:Chapter-12|Chapter 12]] and the regional and thematic chapters and cross-chapter papers of WGII. Therefore, it focuses on generating information on climatic impact-drivers and hazards applicable to assessing impacts on and risks to human and ecological systems whilst noting the potential relevance of these to related contexts such as the United Nations (UN) Sustainable Development Goals and the UN Sendai Framework for Disaster Risk Reduction.

Transparency and reproducibility are promoted in the Atlas chapter implementing FAIR principles for Findability, Accessibility, Interoperability, and Reusability of data ( [[#Wilkinson--2016|Wilkinson et al., 2016]] ). More specifically, the Interactive Atlas provides full metadata of the displayed products (describing both the underlying datasets and the applied post-processing) and most of the figures included in the Atlas chapter can be reproduced using the scripts and data provided in the WGI-Atlas repository (see [[#Iturbide--2021|Iturbide et al., 2021]] and [https://github.com/IPCC-WG1/Atlas ht tps://github. com/IPCC-WG1/Atlas] ).

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