The tipping points at the heart of the climate crisis

Many parts of the Earth's climate system have been destabilised by warming, from ice sheets and ocean currents to the Amazon rainforest - and scientists believe that if one collapses others could follow

The warning signs are flashing red. The California wildfires were surely made worse by the impacts of global heating. A study published in July warned that the Arctic is undergoing an abrupt climate change event" that will probably lead to dramatic changes. As if to underline the point, on 14 September it was reported that a huge ice shelf in northeast Greenland had torn itself apart, worn away by warm waters lapping in from beneath.

That same day, a study of satellite data revealed growing cracks and crevasses in the ice shelves protecting two of Antarctica's largest glaciers - indicating that those shelves could also break apart, leaving the glaciers exposed and liable to melt, contributing to sea-level rise. The ice losses are already following our worst-case scenarios.