A UN scientific report states that human activity is changing the climate in unprecedented and sometimes irreversible ways. The landmark study warns of increasingly extreme heatwaves, droughts and flooding, and a key temperature limit being broken in just over a decade. But scientists say a catastrophe can be avoided if the world acts fast. They hope deep cuts in greenhouse gases could stabilise rising temperatures. For political leaders, the report is another in a long line of wake-up calls but, coming so close to November's COP26 global climate summit, it carries extra weight. UN secretary general António Guterres said, ‘If we combine forces now, we can avert climate catastrophe. But, as the report makes clear, there is no time for delay and no room for excuses. I count on government leaders and all stakeholders to ensure COP26 is a success.’ China and India, two of the worst polluters, have not yet submitted updated climate plans.