As the planet warms due to climate change , extreme heat is threatening global food security by harming crops and livestock and reducing the number of hours farmers can work. A recent report by the U.N. Food and Agriculture Organization and the World Meteorological Organization warned that the impacts of extreme heat are pushing agricultural systems to the brink. The agencies found that half a trillion working hours are lost due to extreme heat each year — and the impacts will only worsen as global temperatures continue to climb. The U.N.'s warning came the day after the Lancet Countdown ‪—‬ an international research collaboration that monitors key indicators of health and climate change ‪—‬ published its own report on health and climate change in Europe. Among its findings, the report highlighted that climate change is already causing heat-related deaths, unsafe working hours and food insecurity.…