Scientists have outlined the worst-case impacts of the climate crisis for the UK, including a 4°C rise in temperature, a 2-metre rise in sea level, and a potential 6°C plunge if key Atlantic Ocean currents collapse. These scenarios, though low probability, are considered plausible and highlight gaps in current planning.
The study, led by Professor Nigel Arnell of the University of Reading, uses historical data, computer simulations, and theory to map extreme outcomes. It warns that temperatures could spike up to 6°C above average in some months, with rainfall tripling normal levels. Arnell stressed these are not predictions but tools for decision-makers to prepare for unlikely but high-impact events.
A collapse of the Atlantic meridional overturning circulation (Amoc) beginning in 2030 could cool the UK by 6°C, severely disrupting agriculture, water resources, and energy demand. Even a partial collapse of the sub-polar gyre would reduce temperatures by 2.5°C. Meanwhile, global sea levels could rise 2.0-2.2 metres around the UK by 2100 if Greenland and Antarctic glaciers collapse rapidly, flooding coastal areas.
The research, published in Earth’s Future and commissioned by the Met Office, aims to fill a gap in risk assessment akin to national security or financial stress tests. The Climate Change Committee has urged adaptation for 2°C and assessment for 4°C, though 2023 adaptation plans were criticised as weak. A government spokesperson said climate change remains a priority.
