A sweeping report compiled by more than 200 researchers over a five-year period paints a stark portrait of the Himalayas’ future. As Kai Schultz and Bhadra Sharma report for The New York Times, the new assessment predicts that the Asian mountain range, formally known as the Hindu Kush Himalayas, will lose at least one-third of its glaciers to climate change by the end of the century. Crucially, this estimate is at the lower end of the spectrum, representing a best-case scenario where efforts to stave off climate change circumvent the most drastic effects of global warming.
In a worst-case scenario where global emissions continue at their current output and temperatures rise by 4 to 5 degrees Celsius, the scientists say that Himalayan ice loss could double, claiming a staggering two-thirds of the region’s glaciers.
The Himalayan mountains—best known as the home of the world’s tallest peak, Mount Everest—stretch across eight South Asian countries, including Nepal, Afghanistan and Myanmar. Roughly 250 million people live in the region, Chelsea Harvey writes for Scientific American, while another 1.65 billion or so rely on the 10 major river basins filled water flowing downstream from melting glaciers.
“This is the climate crisis you haven't heard of," Philippus Wester, a scientist at the International Centre for Integrated Mountain Development who led the report, says in a statement. “Global warming is on track to transform the frigid, glacier-covered mountain peaks ... [into] bare rocks in a little less than a century.”
The Himalayas currently hold more than 30,000 square miles of glacial ice—a figure only surpassed by the North and South Poles, according to National Geographic’s Alejandra Borunda. This ice coverage was once even greater, though: As Damian Carrington notes for the Guardian, rising temperatures have shrunk the region’s glaciers by 15 percent since the 1970s.
Melting is uneven across the more than 2,000-mile-long mountain range, with some glaciers in Afghanistan and Pakistan remaining stable or adding ice, but as temperatures continue to rise, even seemingly secure glaciers will succumb. Between 2050 and 2060, Wester tells Carrington, melting ice will converge on rivers fed by the Himalayas, potentially flooding communities and destroying crops; the report states that agriculture surrounding the Indus, Ganges and Brahmaputra rivers is expected to be most adversely affected.
Interestingly, this trend is expected to reverse beginning in the 2060s, with annual snowfall failing to match ice loss triggered by climate change. Seasonal monsoon rains, which typically aid this snowfall, have already weakened and are predicted to further and depriving locals of the water supply needed to support agricultural efforts. Increasingly unpredictable monsoon rain patterns could also wreak havoc, Wester adds: “One-in-100 year floods are starting to happen every 50 years, he tells the Guardian.
Temperatures across the Himalayas appear to be rising faster than in the rest of the world, Scientific American’s Harvey writes. Although the most ambitious target outlined in the Paris climate agreement focuses on limiting warming to 1.5 degrees Celsius, this figure would likely be closer to 1.8 degrees Celsius in the South Asian region. As the Times’ Schultz and Sharma report, this predicted warming further supports the proposed phenomenon of elevation-dependent warming, which suggests that rising temperatures are not only amplified at higher latitudes such as the Arctic, but also at higher elevations.
The consequences of this warming could be devastating: Borunda explains in National Geographic that as temperatures rise, farmers trying to grow apples or grains on the steep Himalayas will be forced to move their crops further up the mountains in search of cooler night conditions.
Combined, these rising temperatures, alternate bouts of flooding and drought, and extant issues including air pollution and heat waves, portend a dark—and increasingly unavoidable—future for the Himalayan region, which Wester tells Borunda was critically under-studied prior to the release of the new report.
“We can't hide behind an excuse that we don’t have the data, that there’s more research needed—now, we have 650 pages of assessment,” Wester says. “... We know this is going to be tough, [but] we know enough to take action.”