The Himalayas are sometimes called the world’s “third pole” because they are covered with thousands of glaciers. Water from those glaciers helps feed some of the world’s most important rivers, including the Ganges and the Indus. And as those glaciers melt, they will contribute to rising sea levels.
So a lot is at stake in understanding these glaciers and how they will respond in a warming world. Researchers writing in the latest issue of Science magazine make it clear they are still struggling at that task.
Just a few years ago, it seemed that the Himalayas were on the brink of disaster. The U.N.’s Intergovernmental Panel on Climate Change (IPCC) made alarming claims about the fate of all that ice. You can almost see Jeffrey Kargel at the University of Arizona cringe as he describes it.
“One page had the most egregious errors you could imagine, just one after another, including the claim that the glaciers would disappear by 2035,” he says.
But the claim was dead wrong. The error put a lot of egg on the face of the IPCC. But it also sent glacier scientists scrambling. They knew very little about the state and the fate of those glaciers, even the basics.
For example, it is true that a billion people live downstream from those glaciers. But, Kargel says, don’t leap to conclusions based on that statistic alone. “That sort of statement can be exaggerated to imply that somehow if the glaciers disappear, the taps are going to run dry for a billion people. And that’s just patently not the case.”
Various estimates suggest that the glaciers provide 1 or 4 or 10 percent of the water for people downstream. Mostly, though, the rivers are filled by the abundant monsoon rains. Kargel says some specific valleys may run dry, and others may flood. It’s wrong to think of the Himalaya as a monolithic block of ice.
“Some areas of the Himalaya and the nearby ranges such as the Karakoram will see shrinking ice masses, shrinking glaciers,” Kargel says. “But some actually are projected to increase in mass, up to a point.”
In fact, scientists are seeing some glaciers gaining mass today, thanks to increased snowfall. Consider the Karakoram, home to more than 40 percent of the region’s glaciers, says Tobias Bolch of the University of Zurich.
“There, the glaciers — at least during the last 10 years — are gaining mass,” Bolch says, “while in most of the other regions in the Himalaya, they are losing mass.”