The potential collapse of the Atlantic Meridional Overturning Circulation (AMOC), a vital system of ocean currents that includes the Gulf Stream, could lead to a significant decrease in global food production and a sharp increase in food prices, according to a new study.
The AMOC plays a crucial role in regulating global climate by transporting warm water from the tropics towards Europe. Recent research indicates that human-caused climate change may be pushing this system towards a tipping point, which could result in extreme cooling in Northern Europe and disrupt monsoon patterns in Africa and Asia.
Scientists from the non-profit Alliance to Feed the Earth in Disasters (ALLFED) utilized a computer model to simulate the future decline of the AMOC over 100 years, assuming a 2°C rise in global temperatures. Their simulations included a scenario with an AMOC slowdown over the first 50 years to compare the potential impacts.
The study found that by the 50-year mark, global yields for major crops like wheat, maize, and rice decreased by 5.3 percent. However, the impact was not uniform across all regions. Some areas experienced much sharper declines, with countries such as Germany and Ukraine potentially losing up to 19 percent of their crop yields due to rapid cooling. Canada showed a projected 12 percent decrease in production.
"Scandinavia, the United Kingdom and Canada are particularly exposed," said Michael Hinge, senior economist at ALLFED, in comments to Live Science. "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," he added.
If the shock to agricultural supply outpaces adaptation efforts, the economic consequences could be severe, potentially leading to a short-term global price spike of up to 40 percent above current levels.
Previous research, led by climate scientist Paul Ritchie of the University of Exeter, projected that in an AMOC collapse scenario, average temperatures in Britain could fall by approximately 3.4°C by 2080. This could also lead to a significant reduction in rainfall during the spring and summer months, drastically shrinking the area suitable for arable farming in Great Britain from about 32 percent to just 7 percent.
The ALLFED study emphasizes the need for global preparation for significant shifts in food production locations. While some regions might see conditions become more suitable for certain crops, relocating agriculture is a complex process requiring substantial land, water, infrastructure, and investment. Furthermore, regions gaining suitability may lack the capacity to absorb increased production.
The scientists also stressed the importance of international cooperation and maintaining global trade. Restricting exports during harvest shortfalls could exacerbate shortages elsewhere, potentially triggering a worldwide food crisis. Coordinated efforts are crucial, as protectionist policies could worsen the situation.
"There are no easy answers here – an AMOC [collapse] would be deeply catastrophic," Hinge stated. "if that warning light starts flashing, we're not sure what to do with it."
Evidence suggests the AMOC has already weakened by approximately 15 percent since the mid-20th century, attributed to climate change. Some studies indicate a 10 to 24 percent probability that a catastrophic collapse is already unavoidable.
The AMOC functions as part of the global ocean conveyor belt, transferring warm, salty water northward. As this water releases heat to the atmosphere, it cools, becomes denser, sinks, and travels south. This process is influenced by temperature and salinity, with freshwater influx from melting ice potentially disrupting the sinking mechanism and slowing the circulation.