Profound Turmoil Projected: UK's Worst-Case Climate Crisis Outcomes Revealed by Scientists

The direst possible consequences of the climate emergency for the UK have been detailed by researchers, encompassing a searing 4C rise in temperatures to a 6.5-foot surge in ocean levels. Another scenario envisions a decline of 6C in temperature following the shutdown of crucial Atlantic Ocean currents, which would severely impact farming and energy demand.

Plausible Extremes, Not Forecasts

These effects, a number of which are associated with climate tipping points, are viewed as improbable but possible. The team stated that these scenarios plugged a hole in planning that had rendered the UK not ready for catastrophic possibilities.

"The severe weather events we have outlined should not be seen as certainties, but they are plausible," said Nigel Arnell who directed the study. "The nation has been formulating policy in the absence of the methods to test against extreme possibilities. We've now supplied policymakers what they need to plan for climate outcomes they wish to avoid, but must not overlook."

A Spectrum of Extreme Weather Projections

Another collection of worst-case scenarios sets out the potential extent of extreme weather between now and the year 2100. These show that thermometer readings could skyrocket in certain periods by up to 6C higher than average, while rainfall could be triple typical amounts.

The chance of the extreme scenarios occurring cannot be precisely determined due to unknown factors about what measures will be taken to tackle global heating and how the climate system will react. This analysis was likened to defence planning or scenario planning for the banking sector.

Key Possibility Elements

• Four-Degree Warming: Worldwide averages soaring past 4C by 2100 could occur if emissions cuts breaks down or if vicious cycles such as the Amazon basin perishing unleash its vast reserves of carbon. This would lead to extreme and prolonged heat domes and droughts affecting the UK in summer.
• Ocean Circulation Failure: A critical sea current, the North Atlantic current, is weakening and showing signs of collapse due to ocean warming. A collapse starting around 2030 would lead to a 6C cooling in the UK. "Agriculture would be severely challenged and water resources would be completely altered," explained Arnell.
• Rapid Sea Level Rise: A surge of 2.0-2.2 metres around the UK by 2100 could occur if glaciers in the polar regions melt abruptly, flooding seaside communities. Differing from the other scenarios, this risk is already understood by infrastructure experts.
• Clean Air Warming: Global averages could also be increased by about 0.75C if industrial aerosols is sharply cut. This counterintuitive effect occurs because aerosol particles from burning coal block solar radiation from warming the ground.

Preparing for the Unthinkable

These dire projections could be used to inform the development of major projects, including housing developments, energy plants and water management networks. Awareness of these future hazards could also hasten the transition to cut fossil fuel emissions.

The research developed the extreme models using a combination of observed and historical experience, climate models and scientific theory. The scenarios do not take into account broader worldwide issues including the global food shortages and resource wars.

This work was commissioned as part of a government’s adaptation planning initiative. Previous assessments have cautioned that not enough attention was being given to low‐likelihood but high‐impact risks.

Official experts has stated that the UK must "prepare for two degrees of warming" and evaluate the risks for four degrees. Previous adaptation plans have been described as being "insufficient" by some observers.

A national response said: "Global warming is at the center of the country's focus, both building resilience and becoming a low-carbon economy. It is essential that the UK is ready for the consequences."