Profound Disruption Ahead: UK's Worst-Case Global Warming Outcomes Unveiled by Researchers

The most severe potential impacts of the climate crisis for the UK have been outlined by researchers, including a blistering 4C jump in average temperatures to a two-metre surge in ocean levels. A separate possibility foresees a decline of 6C in temperature following the failure of critical Atlantic Ocean currents, which would profoundly upset agriculture and power requirements.

Plausible Extremes, Not Guarantees

These effects, a number of which are associated with critical climate thresholds, are considered as low probability but credible. The researchers stated that these models plugged a hole in planning that had left the UK unprepared for worst-case results.

"The severe weather events we have mapped are not forecasts, but they are possible," commented the professor who directed the study. "Britain has been formulating policy without the methods to plan for extreme possibilities. We've now supplied decision-makers what they need to plan for climate outcomes they hope never happen, but must not overlook."

A Suite of Harsh Climate Projections

A further series of severe models maps the projected severity of severe conditions between now and the end of the century. These show that thermometer readings could soar in particular seasons by up to 6C higher than average, while rainfall could be three times normal levels.

The chance of the extreme scenarios coming to pass could not be calculated due to uncertainty about what action will be enacted to combat global heating and how the planet's climate will respond. This research was described as similar to national security risk assessments or scenario planning for economic stability.

Key Scenario Highlights

• 4C Temperature Rise: Worldwide averages exceeding 4C by 2100 could happen if climate action breaks down or if powerful amplifying effects like the Amazon rainforest perishing unleash its huge repository of carbon. This would cause severe and lengthy heatwaves and water shortages affecting the UK in summer.
• AMOC Shutdown: A major ocean current, the North Atlantic current, is weakening and losing stability due to climate change. A complete failure commencing by 2030 would lead to a 6C cooling in the UK. "Crop production would face immense difficulties and freshwater availability would be fundamentally reshaped," noted the professor.
• Rapid Sea Level Rise: A rise of 2.0-2.2 metres around the UK by 2100 could happen if ice sheets in the Arctic and Antarctic melt abruptly, submerging seaside communities. Unlike the other scenarios, this threat is already understood by infrastructure experts.
• Pollution Paradox: Temperatures could also be driven up by about 0.75C if pollution from industry is drastically reduced. This unexpected result occurs because aerosol particles from fossil fuel combustion scatter solar radiation from warming the ground.

Preparing for the Extreme

The severe models could be used to inform the construction of critical national infrastructure, including housing developments, nuclear power stations and urban drainage systems. Awareness of these environmental threats could also hasten the drive to slash carbon pollution.

The analysis developed the extreme models using a blend of observed and historical experience, digital projections and climate physics. The scenarios do not take into account potential global problems such as the devastation of food supplies and geopolitical instability.

The project was commissioned as part of a government’s adaptation planning initiative. Independent analyses have warned that too little consideration was being allocated to high-consequence, low-probability risks.

An independent advisory body has recommended that the UK must "prepare for two degrees of warming" and examine the dangers for severe warming. Past policy documents have been criticised as being "very weak" by environmental groups.

A national response said: "Global warming is at the core of our national priorities, both adapting for the future and becoming a low-carbon economy. It is vital that the UK is ready for the effects."