The hazard components of representative key risks. The physical climate perspective

Journal Article · Wed Apr 26 00:00:00 EDT 2023 · Climate Risk Management

DOI:https://doi.org/10.1016/j.crm.2023.100516· OSTI ID:1984027

Tebaldi, Claudia  ^[1]; Aðalgeirsdóttir, Guðfinna ^[2]; Drijfhout, Sybren ^[3]; Dunne, John ^[4]; Edwards, Tamsin L. ^[5]; Fischer, Erich ^[6]; Fyfe, John C. ^[7]; Jones, Richard G. ^[8]; Kopp, Robert E. ^[9]; Koven, Charles ^[10]; Krinner, Gerhard ^[11]; Otto, Friederike ^[12]; Ruane, Alex C. ^[13]; Seneviratne, Sonia I. ^[6]; Sillmann, Jana ^[14]; Szopa, Sophie ^[15]; Zanis, Prodromos ^[16]

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1. Pacific Northwest National Laboratory (PNNL), Richland, WA (United States). Joint Global Change Research Institute
2. University of Iceland, Reykjavík (Iceland)
3. Univ. of Southampton (United Kingdom); Royal Netherlands Meteorological Institute (KNMI), De Bilt (Netherlands)
4. National Oceanic and Atmospheric Administration (NOAA), Princeton, NJ (United States). Geophysical Fluid Dynamics Laboratory
5. King's College, London (United Kingdom)
6. Eidgenoessische Technische Hochschule (ETH), Zurich (Switzerland). Institute for Atmospheric and Climate Science
7. Canadian Centre for Climate Modelling and Analysis, Victoria (Canada)
8. Met Office Hadley Center, Exeter (United Kingdom)
9. Rutgers Univ., New Brunswick, NJ (United States)
10. Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
11. Univ. of Grenoble Alpes, Grenoble (France)
12. Imperial College, London (United Kingdom)
13. NASA Goddard Inst. for Space Studies (GISS), New York, NY (United States)
14. Univ. of Hamburg (Germany); CICERO Center for International Climate Research, Oslo (Norway)
15. Univ. Paris-Saclay, Gif-sur-Yvette (France)
16. Aristotle University of Thessaloniki (Greece)

The framework of Representative Key Risks (RKRs) has been adopted by the Intergovernmental Panel on Climate Change Working Group II in order to categorize, assess and communicate a wide range of regional and sectoral key risks, expected to become severe as a consequence of the potentially detrimental convergence of changing climate conditions, exposure and vulnerability of human and natural systems, and responses through (mal)adaptation measures. Other papers in this special issue treat each of eight RKRs by holistically assessing their current status and future evolution as a result of this convergence. However, their treatment cannot always organize such assessment according to a systematic gradation of climatic changes, often times having to extrapolate the big-picture evolution of risk from either qualitative effects of “low” medium” and “high” warming, or limited/focused analysis of the consequences of particular mitigation choices (e.g., benefits of limiting warming to 1.5 or 2C). In this study we offer as systematic a representation as possible – given current literature and assessments – of the future evolution of the hazard components of RKRs. We draw on the assessment of changes in climatic impact-drivers relevant to RKRs described in the 6th Assessment Report by Working Group 1 (WGI) supplemented when needed by more recent literature. We identify the relevant hazards for each RKR, based upon the WGII authors’ assessment, and we report on their current state and expected future changes in magnitude, intensity and/or frequency, linking these changes to Global Warming Levels to the extent possible. For some of these quantities - like regional trends in oceanic and atmospheric temperature and precipitation, some heat and precipitation extremes, permafrost thaw and Northern Hemisphere snow cover - a strong and quantitative relationship with global average temperature change has been assessed. For others - like frequency and intensity of tropical cyclones and extra-tropical storms, and fire weather - the link to increasing global temperatures can only be described qualitatively. For some processes - like the behavior of ice-sheets, or changes in circulation dynamics - large uncertainties about the effects of different levels of warming remain, and for a few others - like ocean pH and air pollution - the composition of the scenario of anthropogenic emissions is most relevant, rather than the warming reached. In almost all cases, however, the basic message remains that every small increment in CO2 concentration in the atmosphere and associated warming will bring changes in climate phenomena that will contribute to increasing risk of impacts on human and natural systems when these changes happen in conjunction with these systems’ conditions of exposure and vulnerability, and in lack of effective adaptation. Our picture of the evolution of RKR-relevant climatic impact-drivers complements and enriches the treatment of RKRs in the other papers in at least two ways: by filling in an often only cursory or limited representation of the physical climate aspects driving impacts, and by providing a fuller representation of their future possible evolution which represents an important component – if never the only one – of the potential future evolution of risk severity.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Biological and Environmental Research (BER); National Aeronautics and Space Administration (NASA); National Science Foundation (NSF); Natural Environment Research Council, UK; European Union (EU)
• Grant/Contract Number: AC05-76RL01830; AC02-05CH11231; 80NSSC20K1724; ICER-2103754; NE/T007443/1; 869304; 2018SE01300001
• OSTI ID: 1984027
• Report Number(s): PNNL-SA-180973
• Journal Information: Climate Risk Management, Vol. 40; ISSN 2212-0963
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

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54 ENVIRONMENTAL SCIENCES