🔗 Share this article

The direst potential impacts of the climate emergency for the UK have been outlined by scientists, ranging from a searing 4C jump in mean temperatures to a 6.5-foot increase in sea level. Another scenario predicts a decline of 6C in temperature following the failure of critical Atlantic Ocean currents, which would severely impact farming and energy demand.

Plausible Outcomes, Not Guarantees

These impacts, some of which are connected to irreversible climate shifts, are considered as unlikely but possible. The researchers explained that these models filled a gap in planning that had left the UK not ready for extreme outcomes.

"The severe weather events we have mapped should not be seen as certainties, but they are credible," commented the professor who directed the study. "Britain has been formulating policy in the absence of the methods to assess worst-case scenarios. We've now supplied decision-makers what they need to prepare for future conditions they pray never occur, but dare not dismiss."

A Suite of Severe Conditions Projections

Another collection of worst-case scenarios details the potential extent of severe conditions between now and the year 2100. These suggest that temperatures could skyrocket in particular seasons by up to 6C above average, while rainfall could be three times normal levels.

The likelihood of the worst-case outcomes coming to pass remains uncertain due to a lack of certainty about what measures will be enacted to tackle climate change and how the climate system will respond. This approach was described as similar to security threat evaluations or scenario planning for economic stability.

Key Possibility Elements

• Severe Heating: Worldwide averages exceeding 4C by 2100 could transpire if international cooperation collapses or if powerful amplifying effects like the tropical forests becoming a net carbon source emit its huge repository of carbon. This would lead to intense and enduring heatwaves and water shortages plaguing the UK in summer.
• AMOC Shutdown: A major ocean current, the Atlantic meridional overturning circulation (Amoc), is losing strength and becoming unstable due to climate change. A full shutdown commencing by 2030 would lead to a 6C cooling in the UK. "Agriculture would face immense difficulties and water supplies would be fundamentally reshaped," said the professor.
• Accelerated Coastal Flooding: A rise of 2.0-2.2 metres around the UK by 2100 could take place if ice sheets in the Arctic and Antarctic disintegrate quickly, submerging seaside communities. In contrast to the other scenarios, this threat is already recognized by planners.
• Pollution Paradox: Temperatures could also be pushed higher by about 0.75C if pollution from industry is sharply cut. This counterintuitive effect occurs because aerosol particles from fossil fuel combustion block sunlight from reaching the ground.

Preparing for the Worst

These dire projections could be applied to guide the construction of major projects, including housing developments, energy plants and water management networks. Understanding these future hazards could also accelerate the push to slash fossil fuel emissions.

The analysis formulated the extreme models using a combination of real-world events, computer simulations and scientific theory. The possibilities omit broader worldwide issues including the devastation of food supplies and increased conflict.

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

The government's climate advisors has stated that the UK needs to "prepare for two degrees of warming" and evaluate the threats for severe warming. Past policy documents have been described as being "insufficient" by environmental groups.

An official statement noted: "Climate change is at the core of this government’s agenda, both building resilience and establishing itself as a clean energy superpower. It is essential that the UK is resilient for the effects."