Even if the world manages to limit future warming to the strictest international temperature goal, four Earth-changing climate 'tipping points' are still likely to be triggered with a lot more looming as the planet heats more after that, a new study said.
that releases massive amounts of greenhouse gases trapped in now frozen land are four significant tipping points that could be triggered at 1.5 degrees Celsius of warming, which is three-tenths of a degree warmer than now. Current policies and actions put Earth on a trajectory for about 2.7 degrees Celsius of warming since pre-industrial times, according to some projections.
Timing is a key issue for tipping points in two ways: when they become triggered and when they cause harm. And in many cases, such as ice sheet collapses, they could be triggered soon — but their impacts, even though inevitable, take centuries to play out, scientists said. A few, such as the loss of coral reefs, cause more harm in only a decade or two.
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. "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.
Rockstrom said 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.