🔗 Share this article

The most severe potential impacts of the global heating for the UK have been mapped by experts, ranging from a blistering 4C increase in average temperatures to a 2-metre increase in sea level. A separate possibility predicts a drop of 6C in temperatures following the shutdown of crucial Atlantic Ocean currents, which would severely impact farming and power requirements.

Credible Extremes, Not Forecasts

These consequences, a number of which are associated with irreversible climate shifts, are viewed as improbable but plausible. The scientists stated that these models plugged a hole in planning that had left the UK not ready for extreme outcomes.

"The severe weather events we have detailed aren’t predictions, but they are credible," commented Nigel Arnell who directed the analysis. "The nation has been making preparations without the tools to plan for extreme possibilities. We've now provided decision-makers what they need to get ready for environmental results they hope never happen, but dare not dismiss."

A Suite of Extreme Weather Scenarios

A further series of dire projections sets out the potential extent of severe conditions between now and the end of the century. These indicate that thermometer readings could soar in certain periods by up to 6C above the norm, while rainfall could be triple normal levels.

The probability of the catastrophic events occurring could not be calculated due to a lack of certainty about what measures will be implemented to address global warming and how the planet's climate will behave. This approach was likened to national security risk assessments or stress tests for economic stability.

Critical Scenario Elements

• 4C Temperature Rise: Planetary heating soaring past 4C by 2100 could happen if emissions cuts fails or if powerful amplifying effects including the Amazon rainforest dying emit its vast reserves of carbon. This would lead to intense and enduring heatwaves and water shortages plaguing the UK in summer.
• Atlantic Current Collapse: A major ocean current, the Atlantic meridional overturning circulation (Amoc), is slowing down and losing stability due to global heating. A collapse starting around 2030 would lead to a 6C cooling in the UK. "Agriculture would be severely challenged and freshwater availability would be drastically changed," noted the lead researcher.
• Sudden Ocean Inundation: A increase of 2.0-2.2 metres around the UK by 2100 could happen if ice sheets in Greenland and Antarctica disintegrate quickly, submerging low-lying areas. Unlike the other scenarios, this risk is already recognized by infrastructure experts.
• Pollution Paradox: Temperatures could also be pushed higher by about 0.75C if airborne particulates is rapidly cleaned up. This paradoxical outcome occurs because aerosol particles from industrial activity scatter sunlight from reaching the ground.

Preparing for the Extreme

These dire projections could be used to inform the building of critical national infrastructure, including expanded cities, power generation facilities and flood defences. Understanding these future hazards could also speed the transition to slash greenhouse gas emissions.

The study developed the severe projections using a combination of observed and historical experience, computer simulations and climate physics. These outcomes omit potential global problems such as the devastation of food supplies and increased conflict.

The research was requested as part of a national adaptation planning initiative. Previous assessments have cautioned that insufficient focus was being allocated to high-consequence, low-probability risks.

An independent advisory body has recommended that the UK needs to "adapt to 2C" and assess the threats for four degrees. Past policy documents have been labeled being "insufficient" by certain experts.

An official statement said: "The climate emergency is at the center of the country's focus, both adapting for the future and transitioning to a clean energy superpower. It is essential that the UK is ready for the impacts."