Global food system emissions imperil Paris climate goals

The global food system's greenhouse gas emissions will add nearly 1 degree Celsius to Earth's surface temperatures by 2100 on current trends, obliterating Paris Agreement climate goals, scientists have warned.

A major overhaul of the sector, from production to distribution to consumption, could reduce those emissions by more than half even as global population increases, they reported in Nature Climate Change.

Earth's surface has warmed 1.2 degrees since the late 1800s, leaving only a narrow margin for staying under the 2015 treaty's core goal of capping warming at "well under" 2 degrees.

Even further out of reach is the aspirational limit of 1.5 degrees, which science subsequently showed to be a much safer threshold to avoid devastating and possibly irreversible climate impacts, including coastal flooding, heatwaves and drought.

"Mitigating emissions from the food sector is essential to working toward a secure climate future," the study's lead author Catherine Ivanovich, a doctoral student at Columbia University in New York, told AFP.

The global food system accounts for about 15 percent of current warming levels, but only a third of national emissions reductions plans under the Paris pact include any measure to cut carbon pollution from agriculture or livestock.

To improve on previous estimates of how much feeding the world adds to global warming, Ivanovich and her colleagues looked separately at the three main greenhouse gases, which vary in potency and staying power in the atmosphere.

Once emitted, carbon dioxide remains in the atmosphere for centuries. Methane only lingers for about a decade but, on that timescale, is almost 100 times more efficient in retaining the Sun's heat.

Methane from belching...