Study: Antarctica’s ice shelves may be melting faster than we thought
The new model was developed by researchers at the California Institute of Technology (Caltech) and the Jet Propulsion Laboratory (JPL). The research, recently published in Science Advances, was conducted in the lab of Andy Thompson, a professor of environmental science and engineering.
Ice shelves are protrusions of the Antarctic ice sheet, found where ice blocks stick out from land and float above the ocean. Ice shelves — each a few hundred meters thick — act as a protective buffer for continental ice to prevent entire ice sheets from flowing into the ocean (which would greatly raise global sea levels). However, the rate of melting of these ice shelves is increasing due to the warming of the atmosphere and ocean due to climate change. This is threatening their ability to keep ice sheets from flowing into the ocean.
“If the mechanism we’ve been studying is active in the real world, it could mean ice shelf melt rates are 20 to 40 percent higher than predicted by global climate models, which typically fail to simulate the Antarctic coast,” Thompson said. These strong currents nearby.”
Led by Senior Research Scientist Mar Flexas, the researchers on this study focused on one region of Antarctica: the West Antarctic Peninsula (WAP). Antarctica is roughly shaped like a disk, except where the WAP protrudes from high polar latitudes into lower, warmer latitudes. It is here that Antarctica is seeing the most dramatic changes from climate change. The team has previously deployed autonomous vehicles in the region, and scientists used data from instrumented elephant seals to measure temperature and salinity in water and ice.
The team’s model takes into account the narrow Antarctic coastal current, which runs counterclockwise around the entire Antarctica. Because it’s so small, it’s an ocean current that many climate models don’t include.
Flexas explained: “Large global climate models do not include this coastal current because it is very narrow, only about 20 kilometers wide, and most climate models only capture currents that are 100 kilometers or more in diameter. Therefore, it is possible that these models Not a very accurate representation of future melting rates.”
The model illustrates how freshwater melted from WWPD’s ice is carried by coastal currents and transported across continents. The less dense fresh water moves rapidly near the ocean surface and traps the relatively warm ocean saltwater at the bottom of the ice shelf. This then causes the ice shelf to melt from below. In this way, increased meltwater in the Antarctic circle could propagate warming by currents along the ocean, which in turn could escalate melting, even on the West Antarctic ice shelf thousands of kilometers away from the peninsula. This long-range warming mechanism may be partly responsible for the accelerated volume loss of the West Antarctic ice shelf in recent decades.
“There are aspects of the climate system that we are still discovering. As we progress in our ability to model the interactions between oceans, ice shelves and the atmosphere, we are able to make more accurate predictions and have a better sense of uncertainty. We may need to revisit some of our projections of sea level rise in the coming decades or century — that’s what we’re going to do,” Thompson explained.