Somewhere dating back to 115,000 years ago, humans or as we may call them homo sapiens were all the while living in groups of hunters and gatherers, to a great extent restricted to Africa. While these primates didn't have any idea, but the Earth was reaching the end of a noteworthy warm period. The warm period was quite like ours but oceans at the time were 20 to 30 feet higher.
Amid this antiquated period, called the Eemian, the seas were about as warm as they are today. A month ago, fascinating new research developed proposing that Northern Hemisphere ice sheets have just reduced similarly to the extent they did in the Eemian, driven by the crazy warming in Arctic districts.
The finding emerged when a group of analysts dealing with Baffin Island, in northeastern Canada, inspected the remaining parts of ancient plants that had risen up out of fast retreating glaciers in the mountains. They also found out that the plants were old for sure, and had likely last grown in that area some 115,000 years ago. That is the last time when there was no ice over the area.
As per Gifford Miller, a geologist at the University of Colorado in Boulder, the last century is as warm as any century over the last 115,000 years. If Miller is not wrong, we have a problem. Oceans then were 20 to 30 feet higher.
Some additional water likely originated from Greenland, whose ice as of now contains more than 20 feet of potential ocean level ascent. Yet, it couldn't have been simply Greenland, since that whole ice sheet did not dissolve at the time. That is why scientists additionally presume a breakdown of the most vulnerable of Antarctica, the West Antarctic ice sheet and it could cause another 10 feet of ocean level rise.
Researchers are presently strongly discussing decisively what could have played out at that point - and how soon they'll play out once more. All things considered, West Antarctica has just been showing signs of retreat.
There are two schools of research, wherein one says that it could be marine ice cliff collapse, which could cause sea level rise from West Antarctica all of a sudden. Another group believes, the changes in the past were at a slow pace which will be the case again.
To comprehend the question, think about the setting of West Antarctica itself. Basically, it's a colossal square of ice for the most part submerged in extremely cool water. Its icy masses sit facing the sea every which way, and toward the focal point of the ice sheet, the ocean bottom slants quickly descending, even as the outside of the ice sheet itself develops a lot thicker, as much as two miles thick altogether.
As much as a mile and a half of that ice rests underneath the ocean level, however there is still a lot of ice above it, as well.
So if gateway glaciers go in reverse - especially an ice sheet named Thwaites, by a wide margin the biggest of them, the ocean would rapidly approach a lot thicker ice.
A model that looked to the Eemian was made along with Pliocene, another warm period in the ancient times, trying to understand how it may have happened and came down to several conclusions.
Marine Ice cliff collapse is a fiasco if you apply it to Thwaites. If Thwaites loses its own ice shelf someday and exposes a vertical front to the ocean, there would be ice cliffs hundreds of meters above the water’s surface. These cliffs would fall into the sea continuously which could cause Antarctica to yield over three feet ice in a century.
Combining Greenland, it would cause six feet of rise this century, worsening the situation furthermore.
The point is that as compared to Greenland, Antarctica has thicker ice which will cause the damage to be worse.
Other school of thought believes that things may not be as bad as being projected, but it is still damaging.
There is no model as of now which says that the damage won’t be lethal if climate change continues to happen at this pace.
Just last week, scientists reported a large cavity opening beneath one part of the Thwaites glacier which was not something that could be predicted. It is a situation that could worsen and well, a repeat of our own geological history may be possible, at a much more damaging level.
Source: WashingtonPost
Image Credit: sciencedaily.com
