'There are no easy answers here': New study forecasts a dire dip in food production if key Atlantic currents collapse

Weakening Atlantic Ocean currents could cripple agriculture in some of the world's major breadbaskets, threatening global food security and raising the price of basic commodities, new research finds.

The study, which hasn't been peer-reviewed yet, investigated how a roughly 60% decline in the Atlantic Meridional Overturning Circulation (AMOC) would impact global food production. The AMOC is a system of ocean currents that regulates the global climate and brings heat from the tropics to the Northern Hemisphere.

However, the system is currently the weakest it's been in more than 1,000 years , having lost 10% to 20% of its strength due to climate change, estimates show.

In the new study, researchers used a computer model to simulate the AMOC's future decline. They modeled 100 years of change, assuming 3.6 degrees Fahrenheit (2 degrees Celsius) of warming above preindustrial levels. The team forced an AMOC slowdown over the first 50 years in one simulation but didn't modify the circulation in a second experiment, which enabled them to compare the world with and without an AMOC failure.

The model's outcomes mirrored the results of previous studies , showing broad cooling in the Northern Hemisphere and a southward shift of the belt of clouds and rain that encircles the globe near the equator. As in past studies , these effects were irreversible on human timescales, said study co-author Michael Hinge , a senior economist at the nonprofit Alliance to Feed the Earth in Disasters (ALLFED).

"Once the damage is inflicted, it stays there," Hinge told Live Science, adding that in the 50 years after the peak rate of AMOC slowdown in the model, the circulation weakened by an extra 20%. The study was posted on ALLFED's website July 7.

Hinge and his colleagues ran three models to look at the most common varieties of wheat, maize and rice, layering these models on top of the AMOC simulations. They found that global yields for these crops decreased by 5.3% by the 50-year mark, once the AMOC had weakened substantially.

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