WELCOME to the warm Anthropocene. The growing volume of global temperature data adds to the evidence that we have left the Holocene and entered a new geological epoch dominated by human activities.

“We’re now a few tenths of a degree above the prior maximum of the Holocene,” says James Hansen of the NASA Goddard Institute for Space Studies in New York City. The Anthropocene is also characterised by sediments bearing human traces, such as plastics and other refuse.

Hansen, speaking at a Royal Society meeting in London, was also critical of a widely adopted target to limit global warming to 2 °C above pre-industrial levels. Feedbacks that take millennia to run their course mean 2 °C could ultimately lead to the melting of polar ice and several metres of sea-level rise, he says.

He adds that the interglacial period 130,000 years ago was just 1 °C warmer than today yet sea levels were 5 metres higher.