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According to a study, global warming is accelerated by the melting of light-colored Arctic sea ice, which exposes the “darker” ocean water to absorb more sunlight.
German researchers found that this process forms a “vicious circle” of positive feedback, which could lead to an additional 0.77 ° F (0.43 ° C) temperature rise.
The consequences of this increase could be considerable, the team warned, and lead to more extreme weather conditions, sea level rise and damage to wildlife.
One study warned that global warming is being accelerated by melting light-colored Arctic sea ice, which exposes “ darker ” ocean water to absorb more sunlight, as in the photo.
“If global ice masses shrink, this changes how much sunlight hitting the Earth’s surface is reflected back into space,” said article author and climate scientist Nico Wunderling of the Potsdam Institute for Research. on climate impact.
“Decreasing ice cover in the Arctic exposes more darker ocean water that absorbs more energy,” he explained of the phenomenon, which scientists call the “albedo effect.”
‘It’s like wearing white or black clothes in the summer. If you wear dark clothes, you warm up more easily, ”continued Dr. Wunderling.
Additional factors include the increase in atmospheric water vapor as more ice is melting. Warmer air can hold more and water vapor increases the greenhouse effect.
‘Melting ice in polar and mountainous regions around the world could lead to a further 0.43 ° C increase in long-term global warming,’ said Dr. Wunderling.
In their study, the researchers modeled the Earth system under different levels of greenhouse gases to create the first estimate of how much warming could be triggered by global ice losses.
Existing forecasts did not take into account the reactions of the planet’s land, ocean and ice masses to rising temperatures.
Announcing the results, the German team warned that “ice loss due to warming leads to warming due to ice loss: a vicious circle”.
The researchers estimated that at carbon dioxide levels of 400 parts per million, similar to today, the loss of the world’s ice sheets would result in an average temperature increase of 0.77 ° F (0.43 ° C).
“This effect is robust for a whole range of carbon dioxide emission scenarios up to 700 parts per million. That’s 29% more warming than in a 1.5 ° C scenario. ‘Said Dr Wunderling.
“If global ice masses shrink, that changes how much sunlight hitting the Earth’s surface is reflected back into space,” said article author and climate scientist Nico Wunderling of the Potsdam Institute for Climate Impact Research.
Contributions to this increase range from 0.09 ° F (0.05 ° C) from the West Antarctic ice sheet to 0.36 ° F (0.2 ° C) as a result of the complete loss of Arctic summer sea ice – a scenario you will probably see in this century.
Such an increase in total temperature will have substantial consequences, the team warned. The global average temperature is currently about a degree higher than in pre-industrial times, with policy makers aiming to keep the rise below two degrees.
‘This is not a short-term risk. The Earth’s ice masses are huge, which makes them very important to our Earth system as a whole, “said the article’s author and climatologist Ricarda Winkelmann, also from the Potsdam Institute.
“It also means that their response to man-made climate change, particularly that of the ice sheets in Greenland and Antarctica, takes place on longer time scales.”
“But even though some of the changes may take hundreds or thousands of years to manifest, it’s possible we will activate them within a couple of decades.”
The researchers performed complex computer simulations. For example, if a huge body of ice on earth is shrinking, there may still be snow, which can still reflect sunlight, just as ice did.
If mountain glaciers and ice on Greenland and West Antarctica go, it would bring another 0.36 ° F (0.2 ° C) to the top of 0.36 ° F due to summer sea ice melt Arctic.
“Yet every tenth of a degree of warming matters to our climate,” said Dr. Winkelmann.
Preventing Earth system feedback loops, or vicious circles, is therefore more urgent than ever. Our results imply a further increase in global mean temperature over intermediate to long time scales. “
‘This is not a short-term risk. The Earth’s ice masses are huge, which makes them very important for our Earth system as a whole, ‘said the article’s author and climatologist Ricarda Winkelmann.
Professor Sir David King, former chief science advisor to four prime ministers, has called on the UK to push ahead with its ten-year climate goals.
He says he is “scared” by the number of extreme weather events we are facing, including the heat wave that swept Europe last year.
“We had predicted temperatures would rise, but we did not anticipate these kinds of extreme events that we will have so soon,” the UN chief weather officer told the BBC.
He was referring in particular to the loss of land and sea ice. The UK is committed to reducing net emissions by 2050.
The full results of the study were published in the journal Nature Communications.
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