🔗 Share this article

The direst potential impacts of the climate emergency for the UK have been detailed by scientists, encompassing a searing 4C rise in average temperatures to a 6.5-foot surge in ocean levels. A separate possibility predicts a decline of 6C in temperatures following the collapse of critical Atlantic Ocean currents, which would massively disrupt farming and power requirements.

Credible Events, Not Predictions

These impacts, certain ones are linked to irreversible climate shifts, are viewed as low probability but possible. The team explained that these projections filled a gap in planning that had left the UK ill-prepared for worst-case results.

"The worst-case scenarios we have detailed aren’t predictions, but they are possible," stated Nigel Arnell who led the analysis. "The UK has been formulating policy lacking the methods to assess extreme possibilities. We've now given policymakers what they need to get ready for future conditions they wish to avoid, but dare not dismiss."

A Spectrum of Harsh Climate Possibilities

A further series of dire projections maps the possible scale of harsh climate between now and the end of the century. These suggest that thermometer readings could skyrocket in some months by up to 6C above the norm, while precipitation could be three times standard measurements.

The probability of the catastrophic events happening cannot be precisely determined due to uncertainty about what measures will be taken to address climate change and how the Earth's systems will react. This analysis was likened to security threat evaluations or scenario planning for the banking sector.

Critical Possibility Highlights

• Severe Heating: Global temperatures rising well above 4C by 2100 could transpire if international cooperation collapses or if vicious cycles including the Amazon basin becoming a net carbon source unleash its vast reserves of carbon. This would cause extreme and prolonged heatwaves and droughts plaguing the UK in summer.
• Atlantic Current Collapse: A major ocean current, the Atlantic meridional overturning circulation (Amoc), is losing strength and showing signs of collapse due to global heating. A collapse beginning in 2030 would lead to a 6C cooling in the UK. "Crop production would be severely challenged and water supplies would be fundamentally reshaped," explained Arnell.
• Rapid Sea Level Rise: A rise of 2.0-2.2 metres around the UK by 2100 could take place if polar ice in the polar regions disintegrate quickly, inundating low-lying areas. Unlike the other scenarios, this risk is already recognized by coastal engineers.
• Pollution Paradox: Temperatures could also be driven up by about 0.75C if pollution from industry is rapidly cleaned up. This paradoxical outcome occurs because aerosol particles from burning coal reflect solar radiation from reaching the ground.

Planning for the Extreme

These dire projections could be applied to guide the building of long-term infrastructure, including expanded cities, energy plants and flood defences. Knowledge about these environmental threats could also speed the drive to slash carbon pollution.

The research created the extreme models using a combination of past data and records, climate models and scientific theory. The scenarios do not take into account potential global problems including the devastation of food supplies and resource wars.

The research was requested as part of a official climate resilience programme. Earlier reports have cautioned that too little consideration was being paid to high-consequence, low-probability risks.

Official experts has said that the UK needs to "prepare for two degrees of warming" and evaluate the risks for 4C. Earlier government strategies have been described as being "inadequate" by certain experts.

A national response noted: "Climate change is at the heart of this government’s agenda, both building resilience and becoming a clean energy superpower. It is vital that the UK is resilient for the effects."