🔗 Share this article

The most severe projected effects of the climate crisis for the UK have been detailed by scientists, ranging from a scorching 4C jump in temperatures to a two-metre surge in sea level. A separate possibility foresees a plunge of 6C in temperatures following the collapse of crucial Atlantic Ocean currents, which would massively disrupt food production and energy needs.

Credible Events, Not Forecasts

These consequences, certain ones are associated with irreversible climate shifts, are viewed as unlikely but plausible. The scientists said that these scenarios addressed a shortfall in risk assessment that had rendered the UK not ready for extreme outcomes.

"The climate extremes we have outlined aren’t predictions, but they are credible," commented Nigel Arnell who oversaw the analysis. "The nation has been formulating policy without the frameworks to plan for extreme possibilities. We've now provided decision-makers what they need to prepare for climate outcomes they hope never happen, but dare not dismiss."

A Suite of Extreme Weather Scenarios

A second set of severe models sets out the possible scale of extreme weather between now and the close of the 2100s. These suggest that thermometer readings could skyrocket in certain periods by up to 6C higher than historical levels, while rainfall could be three times typical amounts.

The probability of the worst-case outcomes happening could not be calculated due to a lack of certainty about what action will be implemented to tackle global heating and how the Earth's systems will respond. This approach was likened to security threat evaluations or stress tests for economic stability.

Major Possibility Highlights

• 4C Temperature Rise: Global temperatures soaring past 4C by 2100 could transpire if international cooperation collapses or if powerful amplifying effects such as the Amazon rainforest dying unleash its enormous store of carbon. This would lead to extreme and prolonged heatwaves and droughts hitting the UK in summer.
• Ocean Circulation Failure: A major ocean current, the Atlantic meridional overturning circulation (Amoc), is slowing down and losing stability 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 resources would be completely altered," said Arnell.
• Accelerated Coastal Flooding: A increase of 2.0-2.2 metres around the UK by 2100 could happen if glaciers in the Arctic and Antarctic melt abruptly, submerging low-lying areas. In contrast to the other scenarios, this threat is already understood by coastal engineers.
• Clean Air Warming: Global averages could also be increased by about 0.75C if industrial aerosols is sharply cut. This unexpected result occurs because aerosol particles from fossil fuel combustion reflect sunlight from warming the ground.

Preparing for the Unthinkable

The worst-case scenarios could be used to inform the development of critical national infrastructure, such as housing developments, power generation facilities and urban drainage systems. Understanding these future hazards could also hasten the push to reduce greenhouse gas emissions.

The study formulated the severe projections using a combination of past data and records, computer simulations and scientific theory. These outcomes do not take into account potential global problems like the devastation of food supplies and resource wars.

The project was initiated as part of a government’s climate resilience programme. Earlier reports have cautioned that too little consideration was being allocated to low‐likelihood but high‐impact risks.

The government's climate advisors has said that the UK needs to "become resilient to moderate heating" and examine the risks for four degrees. Earlier government strategies have been criticised as being "insufficient" by some observers.

An official statement commented: "Global warming is at the center of this government’s agenda, both preparing for impacts and transitioning to a low-carbon economy. It is essential that the UK is ready for the effects."