🔗 Share this article

The gravest projected effects of the climate crisis for the UK have been mapped by researchers, encompassing a blistering 4C rise in average temperatures to a 2-metre increase in sea levels. An alternative projection foresees a plunge of 6C in temperature following the failure of key Atlantic Ocean currents, which would profoundly upset agriculture and energy needs.

Plausible Extremes, Not Forecasts

These impacts, a number of which are linked to climate tipping points, are viewed as low probability but credible. The researchers stated that these scenarios plugged a hole in planning that had rendered the UK not ready for worst-case results.

"The severe weather events we have outlined aren’t predictions, but they are plausible," commented Nigel Arnell who oversaw the analysis. "Britain has been planning lacking the methods to plan for worst-case scenarios. We've now supplied planners what they need to get ready for future conditions they wish to avoid, but can’t afford to ignore."

A Spectrum of Severe Conditions Projections

A further series of dire projections details the possible scale of severe conditions between now and the close of the 2100s. These show that temperatures could skyrocket in certain periods by up to 6C above average, while rainfall could be three times standard measurements.

The chance of the catastrophic events occurring could not be calculated due to unknown factors about what action will be taken to tackle global heating and how the climate system will respond. This approach was likened to national security risk assessments or scenario planning for the banking sector.

Major Scenario Highlights

• Four-Degree Warming: Worldwide averages rising well above 4C by 2100 could transpire if climate action breaks down or if strong feedback loops like the Amazon rainforest dying unleash its vast reserves of carbon. This would result in severe and lengthy heat domes and droughts hitting the UK in summer.
• AMOC Shutdown: A major ocean current, the AMOC, is losing strength and showing signs of collapse due to global heating. A complete failure commencing by 2030 would lead to a six-degree temperature drop in the UK. "Crop production would face immense difficulties and water supplies would be fundamentally reshaped," said Arnell.
• Accelerated Coastal Flooding: A surge of 2.0-2.2 metres around the UK by 2100 could happen if polar ice in the Arctic and Antarctic disintegrate quickly, flooding low-lying areas. In contrast to the other scenarios, this risk is already recognized by coastal engineers.
• Clean Air Warming: Global averages could also be driven up by about 0.75C if industrial aerosols is drastically reduced. This unexpected result occurs because pollution particles from fossil fuel combustion block solar radiation from warming the ground.

Planning for the Extreme

The severe models could be used to inform the building of long-term infrastructure, including expanded cities, energy plants and urban drainage systems. Understanding these environmental threats could also hasten the drive to reduce fossil fuel emissions.

The analysis created the worst-case scenarios using a combination of past data and records, computer simulations and climate physics. The possibilities do not take into account international cascading effects like the agricultural collapse and geopolitical instability.

The research was requested as part of a government’s adaptation planning initiative. Earlier reports have warned that too little consideration was being given to low‐likelihood but high‐impact risks.

Official experts has recommended that the UK needs to "adapt to 2C" and evaluate the threats for severe warming. Past policy documents have been labeled being "inadequate" by some observers.

An official statement said: "Global warming is at the center of our national priorities, both building resilience and becoming a renewable energy leader. It is crucial that the UK is prepared for the impacts."