Antarctic Ice Shelves May Melt Faster Than We Thought – Floating With That?

news7g08/14/2022

4 3 minutes read

Melting of Antarctica's ice sheet could cause sea levels to rise many meters by the end of the millennium - Watts Up With That?

[First paragraph abridged -cr:

A new model… suggests that… may be… could eventually… sea level rise.]

Antarctic ice shelf on a sunny day — PICTURE DESCRIPTION: BEFORE DEVELOPING THIS MODEL, THE TEAM GOES TO ANTARCTICA TO MEASURE THE TEMPERATURE AND SALT OF WATER AND ICE. THEIR NEW MODEL INFORMATION THAT A SAMPLE OF OCEAN NARROW HAS BEEN VISION TODAY CAN ALSO FIND A HUGE Role In The Way Heat Is Accessed By The Ice Cream. see more
CREDIT: ANDY THOMPSON’S COURT

A new model developed by Caltech and JPL researchers suggests that Antarctica’s ice shelves may be melting at a faster rate, which could ultimately contribute to rapid sea level rise. than. This model shows an often overlooked narrow ocean current along the Antarctic coast and simulates how rapidly flowing freshwater, melting from ice shelves, can trap warm seawater densely at the bottom of the ice, making it heat up and melt more.

The study was carried out in the laboratory of Andy Thompsonprofessor of environmental science and engineering, and appeared in the journal Scientific advance on August 12.

Ice shelves are protrusions of the Antarctic ice sheet, found where the ice juts out of the land and floats on top of the ocean. The shelves, several hundred meters thick, act as a protective buffer for the land ice, keeping the entire ice sheet from flowing into the ocean (which would dramatically increase global sea levels). However, the warming atmosphere and warming oceans have caused by climate change are accelerating the melting of these ice shelves, threatening their ability to stop the flow of ice into the ocean.

“If this mechanism we are studying works in the real world, it could mean that the melting rate of the ice shelf is 20 to 40 percent higher than predicted in global climate models, which is normally not possible to simulate these strong currents near the Antarctic coast,” said Thompson.

In this study, led by senior research scientist Mar Flexas, the researchers focused on one region of Antarctica: the West Antarctic Peninsula (WAP). Antarctica is roughly shaped like a disc, except that the WAP protrudes out of extreme high latitudes and into warmer, lower latitudes. This is where Antarctica has seen the most dramatic changes due to climate change. The team has previously deployed autonomous vehicles in the area, and the scientists used data from elephant seal equipment to measure temperature and salinity in water and ice.

The team’s model takes into account the narrow Antarctic Coastal Current that runs counterclockwise around the entire Antarctic continent, a flow that many climate models don’t include because it’s so small.

“Large global climate models do not include this coastal runoff, because it is very narrow – only about 20 kilometers wide, while most climate models only record flows that are 100 kilometers across. or larger,” explains Flexas. “So it’s likely that those models don’t accurately represent future melting rates.”

Model illustrating how freshwater melt from the ice at WAP is carried and transported around the continent by coastal currents. Less dense freshwater moves rapidly closer to the ocean’s surface and keeps marine saltwater relatively warm on the undersides of ice shelves. This then causes the ice sheets to melt from below. In this way, increased meltwater at the WAP could cause climate warming through the Ocean Current, which in turn could also melt ice even on the West Antarctic ice shelves thousands of miles away from the peninsula. thousand kilometers. This remote warming mechanism may be part of the reason that mass loss from the West Antarctic ice shelves has accelerated in recent decades.

“There are aspects of the climate system that we are still exploring,” Thompson said. “As we have made more progress in modeling interactions between the ocean, ice shelf, and atmosphere, we can make more accurate predictions with better constraints on uncertainty. sure. We may need to revisit some projections of sea level rise in the coming decades or centuries — that’s the work we’ll be doing in the future. “

The paper was titled “Antarctic Peninsula Warming Triggers Enhanced Base Melting Rate Across West Antarctica.” In addition to Flexas and Thompson, other co-authors are Michael Schodlok and Hong Zhang of JPL, and Kevin Speer of Florida State University. Funding was provided by the National Science Foundation, NASA’s Physical Oceanography program and the Atmospheric Science program, NASA’s Technology Development and Internal Research program (Earth 2050 project), JPL and Caltech. Caltech manages the JPL for NASA.