As climate change is increasing the temperatures on Earth, our planet is coming closer to dangerous 'tipping points,' which could speed up global warming beyond the capacity of humans to control it, warned the scientists at the UN talks in Bonn.
As per a report by AFP, "Climate change is here. It is dangerous. And it is about to get much worse," said Johan Rockstrom, executive director of the Stockholm Resilience Centre. "In the last two years, evidence has accumulated that we are now on a collision course with tipping points in the earth system," he added.
"The tipping point is when you're exactly in between two states. A tiny perturbation will make the system tip over," said Sybren Drijfhout, a professor at the University of Southampton.
In relation to climate change, these invisible thresholds are a point-of-no-return beyond which exists a world that could fall rapidly out of balance. For example, some scientists did conclude that the planet's surface has already warmed enough, 1.1 degrees Celsius on average, in the last 150 years to lock the temperature in the breakdown of the ice sheet of West Antarctica, which holds enough frozen water to lift global oceans by six or seven metres.
As per the scientists, it may take another 1,000 years, but the ice sheet will melt even if the humankind humanity draws down the greenhouse gas emission, which currently continues to drive global warming.
According to some scientists, the threshold is even higher, perhaps 1.5 degrees Celcius. However, all of them agree that there will come a point of no return. Rockstrom along with other experts identified a dozen of tipping points in a briefing paper, which has been presented at the 196-nation UN talks.
The most horrifying danger is that the change could become abrupt and irreversible, at least on a timescale measured in thousands of years. An increase of 1-3 degrees Celcius is capable of provoking the loss of Arctic summer sea ice and that would result in irreversible melting of parts of the Greenland Ice Sheet. In turn, this will cause the loss of many warm-water coral reefs and the disappearance of many mountain glaciers.
A temperature rise of 3-5 degrees Celcius, on the other hand, would most probably turn large swathes of the Amazon rainforest into savanna and also slow down the Atlantic Meridional Overturning Circulation (AMOC), a deep-sea current that regulates weather on both of the sides of the northern Atlantic. It would also affect the intensity and frequency of El Ninos. Although, on the positive side; it could also green the Sahel region of northern Africa.
If the thermometer goes up beyond 5 degrees Celcius, which is unlikely but not impossible, the world would witness the melting of the East Antarctic Ice Sheet, lifting the level of the seas tens of metres and the loss of Arctic winter sea ice. Perhaps, it would also melt the permafrost that traps nearly twice as much carbon as is being contained in the atmosphere currently.
Right now, the scientists point out, humanity is having a very hard time dealing with the amount of CO2 and methane — the two most important greenhouse gases — we have already released. If Earth itself gets into the act, that task could quickly become overwhelming.
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"It is important to remind everyone of the very reasons why tens of thousands of people are meeting in Bonn," said Hans Joachim Schellnhuber, director of the Potsdam Institute for Climate Impact Research, and co-author of the briefing. "It is because of the unprecedented risk to humanity due to global warming, as revealed by science." This hard reality, he added, may force us to reconsider the "culture of short-term convenience and consumption" that has emerged since the middle of the 20th century.
