India, April 22 -- Extreme heat is pushing global food and farming systems to the brink, threatening the livelihoods of over a billion people as rising temperatures and more frequent heatwaves redefine how food is produced worldwide, a new UN report warns.

The joint report by the Food and Agriculture Organization (FAO) and the World Meteorological Organization (WMO) finds that extreme heat is already causing half a trillion work hours to be lost each year, with impacts set to intensify as temperatures rise.

"Extreme heat is increasingly defining the conditions under which agrifood systems operate," said WMO Secretary-General Celeste Saulo, warning that it acts "as a compounding risk factor that magnifies existing weaknesses across agric...