Global warming is shrinking glaciers faster than thought
Earth's glaciers are melting much faster than scientists thought. That's according to a new study. It shows they are losing 369 billion tons of snow and ice each year. More than half of that in North America.
The most comprehensive measurement of glaciers worldwide found that thousands of inland masses of snow compressed into ice are shrinking. They are shrinking 18 percent faster than an international panel of scientists calculated. They made the calculation in 2013.
The world's glaciers are shrinking five times faster now than they were in the 1960s. Their melt is accelerating due to global warming. It is adding more water to already rising seas.
"Over 30 years suddenly almost all regions started losing mass at the same time." That's according to Michael Zemp. He was lead author of the study. He is also director of the World Glacier Monitoring Service at the University of Zurich.
"That's clearly climate change if you look at the global picture."
The glaciers shrinking fastest are in several places. These include central Europe and the Caucasus region. It includes western Canada and the U.S. Lower 48 states. It includes New Zealand and near the tropics. Glaciers in these places on average are losing more than 1 percent of their mass each year. That's according to a study in the journal Nature.
"In these regions, at the current glacier loss rate, the glaciers will not survive the century." That's what Zemp said.
Zemp's team used ground and satellite measurements. They looked at 19,000 glaciers. That is far more than previous studies. They determined that southwestern Asia is the only region of 19 where glaciers are not shrinking. Zemp said is due to local climate conditions.
Since 1961, the world has lost 10.6 trillion tons of ice and snow, the study found. That's enough to cover the lower 48 U.S. states in about 4 feet of ice.
Scientists have known for a long time that global warming is caused by human activities. These include burning coal, gasoline and diesel. These are for electricity and transportation. These activities are making Earth lose its ice. They have been especially concerned with the large ice sheets. These cover Greenland and Antarctica.
This study, "is telling us there's much more to the story." That's according to Mark Serreze, director of the National Snow and Ice Data Center. It is in Boulder, Colorado. He wasn't part of the study. "The influence of glaciers on sea level is bigger than we thought."
A number of factors are making sea levels rise. The biggest cause is that oceans are getting warmer, which makes water expand. The new figures show glacier melt is a bigger contributor than thought. It is responsible for about 25% to 30% of the yearly rise in oceans, Zemp said.
Rising seas threaten coastal cities around the world. They put more people at risk of flooding during storms.
Glaciers grow in winter and shrink in summer. But the Earth is warming. So they are growing less and shrinking more. Zemp said warmer summer temperatures are the main reason glaciers are shrinking faster.
People think of glaciers as polar issues. But shrinking mountain glaciers closer to the equator can cause serious problems for people who depend on them, said Twila Moon. She is a snow and ice data center scientist who also wasn't part of the study. She said people in the Andes, rely on the glaciers. They rely on them for drinking and irrigation water each summer.
A separate study in Environmental Research Letters confirmed faster melting and other changes in the Arctic. It found that in winter, the Arctic is warming 2.8 times faster than the rest of the Northern Hemisphere. Overall, the region is getting more humid. It is also getting cloudier and wetter.
"It's on steroids, it's hyperactive," said lead author Jason Box. He is a scientist for the Danish Meteorological Institute.