Antarctica could melt even faster than we thought

Antarctica could melt even faster than we thought

A new model developed by researchers at Caltech and NASA’s Jet Propulsion Laboratory (JPL) suggests that Antarctica’s ice may be melting at an accelerating rate, which could help accelerate the rate of sea level rise. oceans.

The researchers say their model takes into account an often-overlooked ocean current flowing along the Antarctic coastline, as well as simulating how quickly freshwater, which has melted from ice sheets , can trap warmer ocean water at the base of the ice, leading to even faster heating and melting.

The polar ice caps are extensions of the Antarctic ice sheet (ice sheet), which is located where ice extends beyond the land and floats in the ocean. These caps, which are several hundred meters thick, act as a protective wall for the ice on land, preventing all the ice from sliding into the ocean (which would greatly increase sea levels).

However, warming of the atmosphere and oceans caused by climate change is increasing the rate at which these ice sheets are melting, threatening their ability to act as blocking structures for the rest of the ice in this area of ​​the Pole. South of our planet.

“If this mechanism that we have studied is active in the real world, it could mean that the rate of ice melt could be 20 to 40 percent higher than the predictions included in global climate models, which generally cannot simulate the strong currents that circulate near the ocean. Antarctic coast,” said Andy Thompson, one of the authors of the study published in Progress of science.

As part of this work, the researchers focused on a single region of Antarctica: the West Antarctic Peninsula. The continent is disk-shaped, except where this peninsula juts out into the ocean, particularly as it is in a warmer, lower latitude area. This is where the southern continent is most affected by climate change.

The research team had previously deployed autonomous vehicles to the area, and the scientists used data from seals with attached measuring devices to assess the temperature and salinity of water and ice.

The model developed by those responsible for this study, which takes into account the ocean current that often passes through the radar, illustrates how fresh water from the melting ice of this peninsula circulates rapidly on the ocean surface and traps salt water of the sea, relatively warm. under the polar caps. This then leads to the fusion of the latter from below.

Ultimately, this phenomenon may spread throughout the Antarctic coast, due to the current, which would mean that the melting is accelerating even thousands of kilometers from where the warming is first felt.

“There are aspects of the climate system that we’re still figuring out,” says Thompson. “As we can further develop our ability to model interactions between the ocean, ice sheets and atmosphere, we will be able to make more accurate predictions, with better uncertainty control. We may need to revise some of the sea level rise predictions for the next few decades or the next century. We will do this work in the future. »

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