Gulf Stream Collapse Could Slash Global Food Production, Study Warns

The collapse of one of the planet’s most important ocean circulation systems could cause global food production to fall sharply, scientists have warned.

The Atlantic Meridional Overturning Circulation (AMOC) is a vast system of ocean currents that transports heat from the tropics towards Europe. The Gulf Stream forms just one part of this wider circulation network.

Recent evidence indicates that human-driven climate change may be pushing the AMOC towards a tipping point. Its collapse could bring much colder conditions to northern Europe, potentially creating a “new Ice Age”, while also disrupting vital monsoon rainfall across Africa and Asia.

Scientists now warn that a weakening AMOC could severely damage agriculture in some of the world’s key farming regions, with the UK among the countries facing significant risks.

In a new study, researchers found that wheat, maize and rice production could fall by almost a fifth in some countries if the ocean current system weakens substantially.

Such a reduction in crop supplies could also push food prices higher around the world.

“The ultimate price impact of an AMOC collapse will depend heavily on the ability of global agricultural supply and demand to adapt to the altered yield environment,” the researchers said.

“If the biophysical shock were to outpace adaptation, the economic impacts could be severe, driving a short-term global price spike of up to 40 per cent above baseline levels.”

The study has not yet been peer reviewed. For their analysis, researchers from the non-profit Alliance to Feed the Earth in Disasters (ALLFED) used a computer model to simulate how the AMOC might decline in the future.

The model projected conditions over the next 100 years, including a global temperature rise of 2°C above pre-industrial levels.

In one scenario, the researchers added an AMOC slowdown during the first 50 years. This allowed them to compare projected conditions with and without a collapse of the circulation system.

The analysis found that a weaker AMOC would cause broader cooling across the Northern Hemisphere and shift the belt of clouds and rainfall near the equator southwards.

After 50 years, global yields of the most common wheat, maize and rice varieties were 5.3 per cent lower in the modelled collapse scenario.

The effects, however, varied considerably between regions.

Germany and Ukraine experienced yield losses of up to 19 per cent as a result of rapid and pronounced cooling, while Canada recorded a 12 per cent decline in production for the same reason.

“Scandinavia, the United Kingdom and Canada are particularly exposed,” Michael Hinge, senior economist at ALLFED, told Live Science.

The latest findings add to earlier research led by Paul Ritchie, a climate scientist at the University of Exeter.

That study estimated that, under an AMOC collapse scenario, average temperatures in Britain would be around 3.4°C lower by 2080 than they would be in a future without the circulation’s collapse.

Rainfall during the April to September season would fall by about 123mm, and the area of Great Britain suitable for arable farming would plunge from about 32 per cent to just 7 per cent.

As part of the new study, the researchers said countries will need to prepare for major changes in where food is produced, with crops potentially having to move into regions where the new climate is more suitable.

But relocating agriculture is far from simple, requiring land, water, infrastructure and investment –and the areas gaining suitable conditions may not have the capacity to take over production.

The scientists also warn that countries cannot simply look after their own food supplies.

Maintaining international trade would be crucial, because restricting exports when harvests fall could amplify shortages elsewhere, they said.

Countries would need to co–ordinate rather than retreat behind protectionist policies – otherwise a fall in production in one part of the world could rapidly become a global food crisis.

The team said they hope their work can help governments understand the need to take swift, effective action if a collapse were to occur.

Mr Hinge warned that currently, ‘if that warning light starts flashing, we’re not sure what to do with it’.

‘There are no easy answers here – an AMOC [collapse] would be deeply catastrophic,’ he added.

Studies have shown that AMOC has already slowed by about 15 per cent since the mid–20th century due to climate change, and could be driven into total collapse in the future.

Scientists say there is an almost one–in–four chance that this catastrophic collapse is already inevitable.