Melting ice threatens London, New York and Tokyo. According to the Research Institute on the Climate Impact of the University of Potsdam and of the Columbia University, these would be some of the most famous cities to be hit hard by the future sea level rise.
There will be, with an increase of 4 degrees in global average temperatures compared to pre-industrial values. The most likely scenario, on the other hand, would jeopardize the survival of many important cities such as London, Mumbai, New York, Shanghai.
Long-term change is not rapid, but it is forever irreversible, the researchers explain. The point of no return is indicated in the model in the increase of 10 degrees, a critical threshold that would correspond to the disappearance of the ice in Antarctica.
The consequent rise in sea level would have disastrous consequences on the cities closest to the coast. University of Potsdam experts said that what we lose now of Antarctica is lost forever: "Antarctica contains more than half the fresh water of the Earth, frozen in a vast ice cap that is nearly 5 kilometers thick.
As the water and atmosphere of the surrounding ocean warm up from human emissions of greenhouse gases, the white cover at the South Pole loses mass and eventually becomes unstable.
Melting ice threatens a lot of metropolies
Due to its vastness, Antarctica's potential for the contribution to sea level rise is enormous: already at 2 degrees of warming, the melting and accelerated flow of ice into the ocean will eventually lead to 2.5 meters of level rise.
At 4 degrees, it will be 6 meters and a half and with 6 degrees of almost 12 meters. Our simulations show that once melted, the ice would not return to its initial state, even if the temperatures were to drop again" Things could go otherwise only if temperatures returned to pre-industrial levels: "A scenario highly unlikely," said experts of the Universities.
Authors of the research of the Columbia University said: "The Antarctic Polar Ice Cap is basically our latest legacy from an earlier period in Earth's history. It has been around for about 34 million years. Now our simulations show.
that once melted, it would not return to its initial state even if temperatures eventually dropped again. Indeed, temperatures would have to return to pre-industrial levels to allow for its full recovery - a highly unlikely scenario.
In other words: what we lose now of Antarctica, is lost forever." The reasons behind this irreversibility are self-imposed mechanisms in the behavior of ice sheets under warming conditions. According to the study, in West Antarctica, for example, the main factor of ice loss is the warm water of the ocean which leads to a higher melting under the ice shelves in the sea, than in its time can destabilize the ice sheet on land.
This causes glaciers the size of Florida to slide into the sea. Once temperatures exceed the threshold of six degrees above pre-industrial levels, the effects of the ice surface become more dominant: that giant ice mountains slowly sink to lower altitudes where the air is warmer, and eventually melt, just as we see in Greenland.