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Good news for the future of the sea level



Latest ice flow around Antarctica. The glacial Thwaites is one of the smallest regions in the left bank of the image.
Enlarge / Latest ice flow around Antarctica. The glacial Thwaites is one of the smallest regions in the left bank of the image.

Glaciers are heavy moods with many characters. Some are very hard to refrain from melting the Earth's climate too much. Others, however, are very sensitive, with a much lower capacity than with far too much pushing.

Much of this is related to the shape of the rock below it. Some glaciers that touch the sea are the foundations of the interior, as you go internally. If the glacier begins to descend, the water of the sea can become ice when the fleet and ice floats more easily, the faster it will be removed.

Each sea glacier has a "dirt line", the ice stops settling on the floor and floats like a shore canoe. When you hear about a "modest ice", it's a mobile part of the glacier. The position of the line of the foot line is that topography is so important, but a study conducted by a group led by Eric Larour at NASA shows how bedrock It can also be moved to make these sensitive glaciers a bit less sensitive

The idea is not new. Glacier retreats can accelerate or slow down in various processes by changing the sea front front. As sea levels rise, the mobile effect increases dramatically, accelerating the loss of ice. And there are more curious factors: glaciers make a serious gravitational attraction on the water of the sea, squeezing a nearby hill. If the glacier shrinks, this gravitational strip is also diminished, which actually allows the water to escape.lower sea ​​level on the coast.

The bed rocks responds to ice mass changes over them. Increasing the ice surface is gradually breaking off (for this reason, the ground under Greenland ice is like a bucket). It allows ice to rock up rocks. And in this case, under a sensitive glacier, it can create more than one rock bottom of the ground line to help tackle ice, which helps to keep the friction that stops retiring.

The question is: what caused it? Many models used to simulate changing glaciers try to penetrate these processes, but they are more serious. In this new study, the researchers directed Antarctica for a kilometer resolution. It turns out that this is quite a big difference.

The research is the Thwaites in the Antarctic glacier, which is amongst the most sensitive and vulnerable in the continent, which is why wildcard is important in the future that will increase the sea levels rapidly. Several versions of the model were executed to simulate it for the next 500 years, to see how it affected the process at a time.

The two major effects were rebounded on the basis of gravitational attraction, as well as the slowing of the glacial Thwaites. Higher-scale resolutions showed that these processes were seen in larger models of larger models that were more powerful in the immediate area of ​​the glacier. Together, the movement of the glaciar line decreased by almost 40% in 2350, with a 25 percent reduction in sea level rise.

This result indicates that while these processes could be important and helpful, long-term glaciers such as Thwaites unfortunately were not very different this century. By 2100, there was a 1% increase in sea level rise. Mass changes had to be made before we had the greatest obstacle or gravitational attraction before weaker.

One of the busiest events on the rise of sea level will continue to be a long-lasting future, even if global warming stagnates. The ice cover wallet takes a long time to respond to a warmer world. This study shows that complex factors of common hardship may not be affected in the coming decades by sensitive glaciers, but they must be modified in a few decades, so that rare changes can be made. news.

Science, 2019 DOI: 10.1126 / science.aav7908 (about DOI).


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