Potential high-impact low-likelihood climate risks in the UK

Arnell, N. W. ORCID: https://orcid.org/0000-0003-2691-4436, Hawkins, E. ORCID: https://orcid.org/0000-0001-9477-3677 and Shepherd, T. G. ORCID: https://orcid.org/0000-0002-6631-9968 (2026) Potential high-impact low-likelihood climate risks in the UK. Environmental Research Letters, 21 (15). 154002. ISSN 1748-9326 doi: 10.1088/1748-9326/ae870f

Abstract/Summary

Climate change has the potential to generate surprises outside the range of change conventionally assumed for adaptation planning and risk assessment. This paper presents policy-relevant indicators of direct climate risks to the UK under five plausible worst-case high-impact low-likelihood scenarios, comparing them with risks under worlds reaching 3 or 4 °C by 2100. The indicators characterise heatwaves and cold spells, wildfire danger, risk to transport and agriculture, and heating and cooling demands. They are based on indicators and thresholds currently used in climate risk management. Enhanced warming above 4 °C and rapidly reducing aerosol emissions both lead to earlier increases in climate risks than anticipated under current emissions policies. Enhanced Arctic Amplification would mean that winter cold extremes would no longer decrease but hot temperature extremes would continue to increase, with implications for transport, energy and emergency management in particular. Collapse of the Atlantic Meridional Overturning Circulation or the Sub-Polar Gyre would have qualitatively different impacts, leading to very large increases in cold weather and drought risks, and substantial changes in the timing of river flows, adversely impacting upon all sectors. A volcanic eruption could lead to persistent low temperatures for two or three years, affecting heating demands and agriculture but having small effects compared to year-to-year variability in other sectors. The assessment here can be used to inform adaptation and resilience planning where actions have long lifetimes or the consequences of system failure are extreme.

Item Type	Article
URI	https://centaur.reading.ac.uk/id/eprint/131209
Identification Number/DOI	10.1088/1748-9326/ae870f
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > NCAS Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	Institute of Physics
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