Some 115,000 years ago, Homo sapiens was living in bands of hunter receivers, which were largely African. We shared the world with the Neanderthal, although it is not clear that it has been discovered yet.
And although these different hybrids did not know, the Earth was coming to the end of a great hot time. It was one that is close to our current climate, but with a large difference – charges were between 20 and 30 feet (6 to 9 meters) higher.
During this ancient period, sometimes known as Eemian, the oceans were
And last month, new research emerged, indicating that the North Hemisphere glacier has already been recovered themselves as far as they did in Eemian, which was being driven by dramatic heating in the Artic regions.
The result when a team of researchers working on Baffin Island, in the north of Canada, published the forests of ancient plants that emerged from mountain glaciers quickly.
And they found that the plants were very old indeed, and that they were probably
That is the last time that the places were not really in envelope, I believe the scientists.
"It's very difficult to find any other explanation, except at least where we are working … the last century has been in the last 1
But if Miller is right, there's a big problem. We have geological records at sea levels from Eemian. And I believe that the oceans, believed by scientists, were 20 to 30 feet (6 to 9 meters) higher.
Some of the other waters from the Web, which have more than 20 feet (6 meters), have potentially increased sea level rise. But Greenland could not be one, as the whole ice sheet did not wipe at the time.
This is why researchers also suspect that Antarctica is the most vulnerable, Western Antarctic ice program. This region could easily supply or exceed 10 feet (3 meters) at sea level.
"There is no way to get ten meters of sea level rise without getting a sea level rise meter from Antarctica," said Rob DeConto, an expert at Antarctica at the University of Massachusetts.
Wanting to understand how Antarctica will fall
Scientists are now focusing intensively on the processes that may occur – and how soon they are & # 39; I will play out again. After all, it has already been shown that Antarctica West, again, is beginning to recess.
A number of researchers, including DeConto, are thinking that they have received a central process – known as a known sea-sea disaster – many levels of sea can be released from the West Arctic in Hurry.
But another group is being tackled with them, whose members are suspected that the changes in the past were slow – and they will be back.
In order to understand the dispute, consider the fragile location of Western Antarctica itself.
In essence, it's a huge block of deeper underwater ice in very cold water. Its glacier sits up the sea in each direction, and towards the middle of the ice sheet, the slopes on the shore fast down, even as the surface of the ice program grows much closer, as long as two miles on whole length.  So many and a half and a half miles of ice are located below sea level, but there is still much ice over it too.
So if the glaciers start the gate back – especially glaciers called Thwaites, most of them – the ocean should have access to a much more intense ice.
It is the idea that there was no ice block in this area, but as an unnamed sea. In a way, the sea got in, providing the external ice defenses, and gradually laid down all of Antarctica and a melting course.
DeConto, with his colleague David Pollard, took a model that looked at the Eemian, and another ancient ancient period known as the Pliocene, to try to understand how it might happen .
In particular, there were two processes using glaciers. The stability of the sea-sheet leaflet, called a "description of a situation where glaciers are totally dropped longer and deeper while moving towards the center.
In this configuration, hot water can cause glaciers to move backwards and downwards, ever exposing more intense ice to the sea – and faster ice flow faster.
So the loss depends on himself.
The existence of already existing ice bills in West Antarctica is likely, but in the model, it was not enough. In addition, DeConto and Pollard added another process they say they are currently playing in Greenland, by a large glacier called Jakobshavn.
Jakobshavn is moving back down the slope of the sea hill, just on the way that Fewaites are afraid to burn much more. But Jakobshavn is doing something else too. It is always ripening thick pieces at its beginning, almost like a baked bread, spreading a slice after wings.
Due to Jakobshavn's ice shelf no longer, a swim extension used to grow over the sea at the front of the glacier and stabilize it. The shelf fell as heated on Greenland in the last two decades.
As a result, Jakobshavn now gives a sharp vertical edge to the sea. Most ice cream is underwater, but it is more than 100 meters (330 feet) above – and for DeConto and Pollard, that is the problem. That is too much to keep.
The ice is not the ice. He pauses. And break. And break.
This extra process, known as a seabird and disaster, brings you completely into disaster if it affects Thwaites. If Thwaites lose their own ice shelf and add a vertical front to the sea, the ice cliffs should be spent hundreds of meters above the surface of the water.
DeConto and Pollard say that these cliffs would continuously affect the sea. And when they put this calculation not only re-invented the Eemian sea level level, it greatly increased their estimate of how much ice Antarctica could have in this century – more than three legs.
As other drivers are rising at sea level, like Greenland, it means that we can see a total of six feet in this area, about two projections. And in the first century, the weight loss would be worse even worse.
"What we have shown, if the type of ice we see in Greenland today is to start the similar sites in Antarctica, then Antarctica is a tougher Ice way, it's a bigger way than ice, the consequences could be really significant at sea level rise, "DeConto said.
In addition, it is vital for the process to understand the past – and so we could replicate
"We can not achieve sea level rising meters early reconstruction of Eemian without making a false break in the ice program model, "DeConto said.
A huge debate on sea ice cliffs
Tamsin Edwards is not sure. King's College of London has an acneologist, a leading author – with some other experts in Antarctica – a study published in Wednesday in Nature (the same magazine published by DeConto and Pollard in 2016) to his model disputes, heavily.
Using a statistical technique to examine the results, Edwards and his co-operation are looking for the need to top the ice cliffs to reflect past past periods.
They offer lower-rise abilities at the level of Antarctica in this century. If they are correct, the worst case is back to about 40 centimeters, or slightly above a leg, rather than three or four feet.
"Things could not be as awful as the last study predicted," Edwards said. "But they are still bad."
It is a new science, she said, and without more shaping, it's not clear how ice cliffs will add to sea level rise.
But then what happened in the Eemian? Edwards seems to have taken a long time to lose West Antarctica. Was not it fast. After all, the geological period was all thousands of years.
"We need a lot of people, and the ice sheets are not responsible for ten years, they are slow animals," she said.  Story says he learns something from the criterion.
"The Edwards study shows the need for deeper statistics than we applied to our 2016 model output, but the models are changing rapidly and have changed dramatically since 2016 , "he said in a written statement.
But he does not support sea ice cliffs. The new attitude, DeConto, said that "these processes are not important at sea level levels in the future. And I think it's a dangerous message."
He's sure he has his allies. Richard Alley, a recognized acrobatologist at Penn State University, wrote to DeConto and Pollard, an email that has no strange and unexpected physical process with the retreat; It has been happening now in some places, which happened before, and it is expected where there is a high enough temperature in sea or air flowing into the ocean. "
An Eemian – but worse?
There is nothing important to consider – Eemian happened not to people who issued many greenhouse gases.
Atmospheric carbon dioxide was much lower than today. Instead, the event was driven by changes to the Earth's orbit around the sun, which would cause the sunlight to fall to the northern hemisphere.
The difference is great , this time around, people are warming things much faster than believed after in the geological history.
And a big difference, Ted Scambos, a researcher from Antarctica who is in charge of the United States of a millionmillion international mission to study Ice Thighites, who is a senior researcher at the National Snow and Ice Data Center in Colorado.
"The current speed of climate change is very fast," her name rt Scambos, and the heat rate could cause glaciers to behave differently than they did in the past.
Accordingly, Scambos says the current debate – that is the debate that must happen "- but does not diminish the fate of Thwaites Glacier if it leaves a lot.
" There is no model that says ice It will not be accelerated if it gets into those conditions, "Scambos said." It must be done. "
People were not near Antarctica in Eemian – and in modern times we have never had glaciers as well as the drops of the Teeth. It's possible that something will happen that I have no fault or predictions.
Just last week, for example , scientists reported that there was a great opening below one part of the glacier – they said that models could not be predicted.
Nowadays it is a major part in trying to figure out what could happen – before doing it really. It will help decide what people, organizers and industrialists and masters of fossil fuels intend to repeat, to drive our own geological report again.
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