🔗 Share this article

The direst projected effects of the climate emergency for the UK have been outlined by researchers, including a scorching 4C rise in mean temperatures to a 2-metre surge in sea levels. An alternative projection predicts a plunge of 6C in temperatures following the failure of critical Atlantic Ocean currents, which would severely impact food production and energy needs.

Possible Outcomes, Not Predictions

These effects, certain ones are linked to critical climate thresholds, are viewed as improbable but plausible. The scientists stated that these models plugged a hole in forecasting that had rendered the UK unprepared for worst-case results.

"The worst-case scenarios we have mapped are not forecasts, but they are plausible," commented Nigel Arnell who oversaw the research. "The UK has been planning without the methods to test against extreme possibilities. We've now supplied decision-makers what they need to get ready for climate outcomes they pray never occur, but must not overlook."

A Spectrum of Harsh Climate Possibilities

Another collection of worst-case scenarios sets out the possible scale of harsh climate between now and the year 2100. These suggest that thermometer readings could skyrocket in some months by up to 6C higher than the norm, while precipitation could be triple normal levels.

The likelihood of the worst-case outcomes occurring remains uncertain due to uncertainty about what action will be enacted to combat climate change and how the planet's climate will respond. This approach was described as similar to security threat evaluations or stress tests for the banking sector.

Key Scenario Details

• Four-Degree Warming: Global temperatures soaring past 4C by 2100 could happen if emissions cuts collapses or if powerful amplifying effects including the Amazon basin dying unleash its vast reserves of carbon. This would cause intense and enduring heat domes and droughts plaguing the UK in summer.
• Ocean Circulation Failure: A major ocean current, the AMOC, is weakening and losing stability due to global heating. A complete failure starting around 2030 would lead to a 6C cooling in the UK. "Agriculture would face immense difficulties and water resources would be fundamentally reshaped," noted the professor.
• Accelerated Coastal Flooding: A rise of 2.0-2.2 metres around the UK by 2100 could take place if glaciers in the polar regions melt abruptly, inundating low-lying areas. Unlike the other scenarios, this threat is already understood by planners.
• Pollution Paradox: Temperatures could also be increased by about 0.75C if airborne particulates is drastically reduced. This paradoxical outcome occurs because tiny specks from fossil fuel combustion reflect sunlight from reaching the ground.

Preparing for the Extreme

The worst-case scenarios could be applied to guide the development of long-term infrastructure, for example expanded cities, energy plants and urban drainage systems. Awareness of these environmental threats could also hasten the push to cut fossil fuel emissions.

The research formulated the worst-case scenarios using a blend of observed and historical experience, digital projections and established principles. The scenarios omit international cascading effects including the agricultural collapse and resource wars.

The research was initiated as part of a official adaptation planning initiative. Earlier reports have cautioned that insufficient focus was being allocated to catastrophic yet improbable risks.

The government's climate advisors has said that the UK must "prepare for two degrees of warming" and assess the threats for four degrees. Earlier government strategies have been criticised as being "insufficient" by environmental groups.

A national response commented: "Climate change is at the heart of this government’s agenda, both adapting for the future and establishing itself as a renewable energy leader. It is essential that the UK is ready for the consequences."