Antarctic ice could be more vulnerable to warming.

An examination of the ice sheets from 18 to 16 million years ago shows that they may be more vulnerable to warming.


An examination of the ice sheets from 18 to 16 million years ago shows that they may be more vulnerable to warming.

Understanding how the West Antarctic ice sheet responded to a warmer climate millions of years ago could improve predictions about its future, according to a new study published in Nature.

However, the contribution of the larger East Antarctic Ice Sheet (EAIS) and the smaller West Antarctic Ice Sheet (WAIS) to past sea-level rise was uncertain. Now Imperial College scientists working under the International Ocean Discovery Program show that the extent of the WAIS was larger than previously thought during the coldest periods of the Miocene.

It means that it contributed more to sea-level rise than was thought. As the world warms, this information will help researchers better predict the future.

Previously, it was thought that the sea level rise was due to the melting of the EAIS during the warmest periods of the past 23 million years.

Ice sheet models show that parts of the EAIS remained even during the warmest periods of the history of the planet.

Jim Marschalek is finishing his Ph.D. with the Association for Doctoral Training in Science and Solutions for a Changing Planet.

He claims that his observations help inform scientists about the state of the Earth. The West Antarctic Ice Sheet, which is vulnerable to rapid ice mass loss today, will respond under various warming scenarios in the future, thanks to our past observations.

The research team drilled into the Ross Sea to find layers that correspond to the hottest and coldest periods. They found evidence that material was deposited far out to sea.

This was possible because in the past more of the land area beneath the WAIS was above sea level, which allowed more ice to settle on this part of the continent compared to today. As our planet warms, the study shows how the WAIS could raise sea level a lot.

The WAIS is now considered to be very vulnerable to oceanic and atmospheric warming. This new study supports that idea, as it shows that it expanded and contracted significantly during the Miocene.

The current human-induced warming of the climate is occurring at a very rapid rate. Now that the geological information matches the models, scientists can be more confident that the models capture the response of the WAIS in the past, helping to predict how Antarctica may respond to changes both in the short term and over several hundred or thousands of years.

If action is not taken now to curb greenhouse gas emissions, the effects of climate change on the ice sheets will continue.

Tina van de Flierdt, from Imperial's Department of Earth Sciences and Engineering, said that the projected sea-level rise by the end of this century is nowhere near the levels we know existed in the geological.

"The good news is that the large ice sheets are relatively slow to respond to environmental change, so we could still avoid a large loss of ice in many areas," he continues. The bad news is that the lower areas of the ice sheet have a tipping point, and we don't yet fully understand where that point of no return is."

Keeping future warming below two degrees, and ideally at 1.5 degrees, is the goal to aim for and requires a 50% reduction in emissions by 2030.

More land area fell below sea level, permanently increasing the sensitivity of the West Antarctic Ice Sheet to changing ocean conditions, as shown by the research.

The team wants to study the low-lying and vulnerable parts of the West and East ice sheets.

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