With just a few more tenths of a degree new tipping points become more possible and even likely that includes a slow down of northern polar ocean circulation that can ripple into dramatic weather changes especially in Europe, loss of certain areas of Arctic sea ice, glaciers collapsing worldwide and utter failure of the Amazon rain forest. While the ice sheets with several meters or yards of potential sea rise can reshape coastline over centuries, Rockstrom said to him the loss of coral reefs is his biggest concern because of the “immediate impacts on human livelihoods.” Hundreds of millions of people, especially poorer tropical area residents, depend on fisheries linked to the coral reefs, McKay said. Study co-author Johan Rockstrom, director of the Potsdam Institute for Climate Impact Research in Germany, likened it to someone lighting a fuse on a bomb “and then the fuse will burn up until the big bang and the big bang may be further down the line.” “When you start tipping over backwards you have in that case a very simple kind of feedback on the forces of gravity operating on propelling you backwards until SPLAT,” Lenton said. Lenton likes to think of tipping points like someone leaning back on a folding chair.

The concept of tipping points have been around for more than a decade but this study goes further looking at temperature thresholds for when they may be triggered and what impacts they would have on people and Earth and in the past 15 years or so “the risk levels just keep going up,” Lenton said. “That ice sheets collapsing is kind of that thousand-year timescale, but it’s still bequeathing an entirely different planet to our descendants.”

“It’s a future generation issue,” said study lead author David Armstrong McKay, a University of Exeter Earth systems scientist.

Arctic ice driver incident report