🔗 Share this article

The gravest possible consequences of the climate crisis for the UK have been mapped by experts, ranging from a scorching 4C rise in temperatures to a 6.5-foot rise in sea levels. An alternative projection predicts a plunge of 6C in temperatures following the collapse of crucial Atlantic Ocean currents, which would severely impact agriculture and energy needs.

Possible Extremes, Not Predictions

These effects, a number of which are connected to irreversible climate shifts, are seen as low probability but credible. The scientists stated that these models addressed a shortfall in risk assessment that had rendered the UK not ready for catastrophic possibilities.

"The worst-case scenarios we have detailed are not forecasts, but they are credible," stated Nigel Arnell who oversaw the study. "The nation has been planning without the frameworks to assess catastrophic outcomes. We've now given decision-makers what they need to plan for climate outcomes they pray never occur, but must not overlook."

A Range of Severe Conditions Scenarios

Another collection of severe models sets out the projected severity of extreme weather between now and the end of the century. These suggest that thermometer readings could soar in certain periods by up to 6C higher than the norm, while precipitation could be 300% of normal levels.

The probability of the worst-case outcomes happening remains uncertain due to uncertainty about what measures will be implemented to tackle global warming and how the climate system will behave. This approach was described as similar to national security risk assessments or stress tests for economic stability.

Critical Scenario Elements

• Four-Degree Warming: Planetary heating rising well above 4C by 2100 could occur if emissions cuts breaks down or if powerful amplifying effects including the tropical forests becoming a net carbon source emit its vast reserves of carbon. This would result in intense and enduring heat domes and dry spells affecting the UK in summer.
• Atlantic Current Collapse: A major ocean current, the AMOC, is losing strength and losing stability due to global heating. A full shutdown starting around 2030 would lead to a drastic cooling in the UK. "Farming would be severely challenged and freshwater availability would be fundamentally reshaped," explained the lead researcher.
• Sudden Ocean Inundation: A increase of 2.0-2.2 metres around the UK by 2100 could take place if ice sheets in Greenland and Antarctica disintegrate quickly, flooding coastal cities and towns. In contrast to the other scenarios, this possibility is already recognized by coastal engineers.
• Aerosol Effect: Temperatures could also be increased by about 0.75C if pollution from industry is drastically reduced. This unexpected result occurs because aerosol particles from fossil fuel combustion scatter sunlight from warming the ground.

Preparing for the Unthinkable

The worst-case scenarios could be applied to guide the construction of long-term infrastructure, for example new towns, energy plants and urban drainage systems. Awareness of these future hazards could also hasten the drive to slash greenhouse gas emissions.

The research created the worst-case scenarios using a blend of observed and historical experience, digital projections and established principles. The possibilities omit broader worldwide issues including the devastation of food supplies and geopolitical instability.

The research was initiated as part of a government’s adaptation planning initiative. Independent analyses have cautioned that not enough attention was being given to high-consequence, low-probability risks.

Official experts has said that the UK must "become resilient to moderate heating" and assess the risks for severe warming. Earlier government strategies have been described as being "insufficient" by some observers.

A government spokesperson noted: "Climate change is at the heart of this government’s agenda, both preparing for impacts and establishing itself as a clean energy superpower. It is vital that the UK is resilient for the consequences."