A major UN scientific report warns of increasingly extreme heatwaves, droughts, and flooding due to human activity changing the climate in unprecedented and sometimes irreversible ways. The report states that human influence has warmed the atmosphere, oceans, and land, and that the consequences of climate change will continue to worsen unless drastic action is taken. The report's authors believe that deep cuts in greenhouse gas emissions could stabilize rising temperatures, but that a catastrophe can only be avoided if the world acts quickly. The report's findings will be a key topic at the upcoming COP26 climate summit.