Climate Change: Hotting Up To The 4 Tipping Points

(MENAFN- Gulf Times)

Even if the world somehow 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, says a new study published in the journal Science. An international team of scientists looked at 16 climate tipping points — when a warming side effect is irreversible, self-perpetuating and major — and calculated rough temperature thresholds at which they are triggered. With only a few more tenths of a degree of warming from now, at 1.5 degrees Celsius warming since pre-industrial times, four move into the likely range, the study explained.
The irreversible collapse of the Greenland and West Antarctic ice sheets, more immediate loss of tropical coral reefs around the globe and thawing of high northern permafrost that releases massive amounts of greenhouse gases trapped in now frozen land are four significant tipping points that could be triggered at 1.5C of warming, which is three-tenths of a degree warmer than now. Current policies and actions put Earth on a trajectory for about 2.7C of warming since pre-industrial times, according to some projections. The study co-author Tim Lenton, an Earth systems scientist at the University of Exeter in the UK, stated that there's a distinct chance some of these tipping points are going to be unavoidable and“therefore it's really important we do some more thinking about how we're going to adapt to the consequences.”
Timing is a key issue for tipping points in two ways: when they become triggered and when they cause harm. 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.“It's a future generation issue,” said study lead author David Armstrong McKay, a University of Exeter Earth systems scientist.“That ice sheets collapsing is kind of that thousand-year timescale, but it's still bequeathing an entirely different planet to our descendants.”
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,” said Lenton. While the ice sheets with several feet of potential sea rise can reshape coastline over centuries, the loss of coral reefs is the biggest concern for study co-author Johan Rockstrom, director of the Potsdam Institute for Climate Impact Research in Germany, 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.
With just a few more tenths of a degree new tipping points become more possible and even likely that includes a slowdown 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. Some of these tipping points, like the permafrost thaw, add to and accelerate existing warming. The only relief is what McKay said:“Even if we do hit some of those tipping points, it will still lock in really substantial impacts we want to avoid, but it doesn't trigger some sort of runaway climate change process. That's not the case at 1.5C and means how much further warming occurs beyond 1.5C is still mostly within our power to effect.”

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