If you've been paying attention, you know that glaciers are melting. But now there's even more unsettling news — that melt is happening at an alarmingly fast rate, reports Tim Radford for The Guardian.
Currently, glaciers are losing between a foot-and-a-half and five feet of ice every year, a rate that is two to three times faster than the average rate for the 20th century, according to data from the World Glacier Monitoring Service. Like its name suggests, the organization keeps tabs on glaciers around the planet using onsite measurements, satellite and aerial photographs and even historical data from written sources.
A team of researchers, including Michael Zemp from the WGMS, report their findings in the Journal of Glaciology. They analyzed more than 120 years worth of data on glaciers in more than 30 countries. "Exact measurements of this ice loss are reported from a few hundred glaciers only," Zemp says in a statement from the University of Zurich, where the WGMS is based. "However, these results are qualitatively confirmed from field and satellite observations for tens of thousands of glaciers around the world."
Researchers are watching the average get faster — even though they have measured a few advancing glaciers, the vast majority of glaciers are retreating instead. None of the advancing glaciers have come close to the maximums achieved during the Little Ice Age, a period of cooling that started in the sixteenth century and ended around 1850. Researchers note that the retreat is profound enough that even if climate change somehow stopped and temperatures remained stable, glaciers would likely to continue to melt.
The news aligns with another recent study showing that Greenland’s glaciers are among the fast-melting ice, thanks to more ocean water exposure than previously estimated. Fast or slow, the disintegration of Greenland's glaciers is of particular concern — they contain so much water that they could make the sea level rise by as much as 20 feet.