Antarctic glacier retreated 3 miles in 22 years, threatening global sea-level rise

https://www.usatoday.com/story/news/world/2020/03/23/global-warming-antarcticas-denman-glacier-melted-3-miles-22-years/2898204001/

Doyle Rice
Mar. 23, 2020

As the global climate heats up, some of the great ice sheets and glaciers in Antarctica are melting, a few of them rapidly. One, East Antarctica’s Denman glacier, has retreated nearly 3 miles in just the past 22 years, according to a new study.

Researchers are concerned that the shape of the ground surface under the ice sheet could make it even more susceptible to a climate-driven collapse. "If fully thawed, the ice in Denman would cause sea levels worldwide to rise almost 5 feet," the University of California-Irvine said in a statement.

“East Antarctica has long been thought to be less threatened (than West Antarctica), but as glaciers such as Denman have come under closer scrutiny by the cryosphere science community, we are now beginning to see evidence of potential marine ice sheet instability in this region,” said study co-author Eric Rignot, a scientist at the University of California-Irvine.

•••••

Sea-level rise is one of the main effects of human-caused climate change. It's important here in the United States because almost 40% of the U.S. population lives in relatively high population-density coastal areas, where sea level plays a role in flooding, shoreline erosion and hazards from storms, according to the National Oceanic and Atmospheric Administration.

And globally, eight of the world’s 10 largest cities are near a coast, the United Nations' Atlas of the Oceans reports.

Overall, NOAA said global sea levels have risen about 8 to 9 inches since 1880, and about a third of that is coming in just the last 2½ decades. Most of that rise is because of meltwater from glaciers and ice sheets and the expansion of seawater as it warms.

•••••

The study was published Monday in the peer-reviewed journal Geophysical Research Letters, a publication of the American Geophysical Union.