Earth’s glacier could face a staggering loss of up to 40% of their mass with a 1.5 degrees Celsius temperature increase by the year 2100, according to a new study.
Lead author David Rounce, now an assistant professor at Carnegie Mellon University, conducted extensive research in the Himalayas, closely observing the Imja-Lhotse Shar Glacier’s rapid retreat and the expansion of its associated lake.
This comprehensive research, which factored in glaciers worldwide (excluding the Greenland and Antarctic ice sheets), endeavours to predict the impact of global temperature increases ranging from 1.5 to 4 degrees Celsius above pre-industrial levels.
With a 1.5 degrees Celsius temperature increase, approximately 50% of the world’s glaciers are projected to vanish, contributing to a 9-centimeter (3.5-inch) rise in sea levels by 2100.
Should global temperatures soar by 2.7 degrees Celsius, in line with climate pledges made at the Conference of Parties (COP26) of the UN Framework Convention for Climate Change, nearly all glaciers in Central Europe, western Canada, and the United States (including Alaska) will have melted.
In the worst-case scenario of 4 degrees Celsius warming, a staggering 80% of the world’s glaciers will disappear, leading to a 15-centimeter (6-inch) increase in sea levels.
“Regardless of temperature increase, the glaciers are going to experience a lot of loss,” cautioned Rounce. “That’s inevitable.”
UNPRECEDENTED DATA AND MODELING
Rounce and his colleagues broke new ground by utilizing satellite-derived mass change data for all of the world’s 215,000 glaciers. Their advanced model harnessed “new satellite-derived datasets that were not available on a global level before,” highlighted Regine Hock, a glaciology professor at the University of Alaska and the University of Oslo. This model incorporated critical data from NASA’s Terra satellite’s Japan’s Advanced Space borne Thermal Emission and Reflection Radiometer (ASTER), along with data from USGS-NASA Landsat 8 and ESA’s Sentinel satellites.
The model also accounted for glacial debris cover, encompassing rocks, sediment, soot, dust, and volcanic ash found on glacier surfaces. This debris, though challenging to measure due to varying thickness, significantly influences glacial melting. A thin layer can intensify melting, while a thick layer can act as insulation and reduce it.
GLOBAL IMPACT AND CLIMATE CHANGE INDICATORS
Glaciers in remote regions, far from human activity, serve as potent indicators of climate change. Swiftly receding glaciers have far-reaching consequences, affecting freshwater availability, landscapes, tourism, ecosystems, the frequency and severity of hazards, and, notably, sea level rise. As Ben Hamlington, leader of NASA’s Sea Level Change Team, points out, sea level rise is a pervasive concern affecting nearly every corner of the Earth.
A MESSAGE OF HOPE
David Rounce emphasizes that the study does not intend to frame the glacier loss in a negative light. He underscores the potential to make a difference. He believes it carries an essential message of hope. It carries the ability to address and mitigate the challenges posed by climate change.