The final global average temperature calculated for 2024 was not only the hottest year since global temperature records began in 1850, but also the first year to pass a milestone set by world leaders to try to keep the worst impacts of climate change at bay,

Two years ago, at the United Nations COP27 climate conference in Egypt, UN Secretary-General António Guterres warned that global leaders needed to address greenhouse gas emissions to keep air temperatures from rising more than 1.5 degrees Celsius above preindustrial levels by the year 2100.