Significant Turmoil Ahead: UK's Worst-Case Climate Emergency Outcomes Laid Bare by Researchers

The most severe projected effects of the climate emergency for the UK have been outlined by researchers, encompassing a blistering 4C jump in mean temperatures to a 2-metre rise in sea level. An alternative projection envisions a plunge of 6C in temperature following the collapse of critical Atlantic Ocean currents, which would severely impact food production and power requirements.

Credible Extremes, Not Forecasts

These effects, some of which are associated with irreversible climate shifts, are seen as improbable but possible. The scientists stated that these projections plugged a hole in planning that had left the UK not ready for extreme outcomes.

"The climate extremes we have detailed are not forecasts, but they are credible," stated Nigel Arnell who oversaw the analysis. "The UK has been making preparations in the absence of the methods to plan for extreme possibilities. We've now given policymakers what they need to plan for environmental results they wish to avoid, but must not overlook."

A Suite of Extreme Weather Possibilities

A second set of severe models details the possible scale of harsh climate between now and the end of the century. These indicate that temperatures could rocket in some months by up to 6C above the norm, while rainfall could be triple normal levels.

The likelihood of the catastrophic events occurring cannot be precisely determined due to a lack of certainty about what steps will be taken to combat global heating and how the climate system will behave. This research was likened to national security risk assessments or resilience checks for financial systems.

Critical Possibility Elements

• Four-Degree Warming: Planetary heating rising well above 4C by 2100 could happen if international cooperation collapses or if vicious cycles including the tropical forests dying release its huge repository of carbon. This would lead to extreme and prolonged heatwaves and water shortages hitting the UK in summer.
• Atlantic Current Collapse: A major ocean current, the AMOC, is slowing down and becoming unstable due to ocean warming. A full shutdown beginning in 2030 would lead to a drastic cooling in the UK. "Agriculture would struggle enormously and water supplies would be fundamentally reshaped," explained Arnell.
• Sudden Ocean Inundation: A surge of 2.0-2.2 metres around the UK by 2100 could occur if glaciers in the Arctic and Antarctic melt abruptly, inundating coastal cities and towns. Unlike the other scenarios, this risk is already known by coastal engineers.
• Pollution Paradox: Temperatures could also be increased by about 0.75C if airborne particulates is rapidly cleaned up. This unexpected result occurs because pollution particles from industrial activity block sunlight from reaching the ground.

Building Resilience Against the Extreme

The severe models could be applied to guide the development of critical national infrastructure, for example housing developments, nuclear power stations and flood defences. Knowledge about these climate risks could also hasten the drive to cut greenhouse gas emissions.

The study created the worst-case scenarios using a combination of past data and records, climate models and scientific theory. These outcomes do not take into account broader worldwide issues such as the agricultural collapse and resource wars.

This work was commissioned as part of a national risk assessment framework. Independent analyses have warned that insufficient focus was being given to high-consequence, low-probability risks.

An independent advisory body has recommended that the UK must "become resilient to moderate heating" and examine the dangers for four degrees. Earlier government strategies have been labeled being "very weak" by environmental groups.

A national response noted: "Global warming is at the center of the country's focus, both building resilience and establishing itself as a low-carbon economy. It is crucial that the UK is prepared for the effects."