The study conducted with aimed to measure the movement and thickness of global glaciers gives a clearer picture of the globe’s icebound freshwater resources. A study published in the Journal ‘Nature Geoscience’, the worldwide survey to measure the movement and thickness of the world’s glaciers, measured the velocity and depth of over 250,000 mountain glaciers. The research called for revising the earlier estimates of glacial ice volume, suggesting that there is 20 per cent less ice available in the global glaciers than previously thought for the sea-level rise.
According to the researchers, from the Institute of Environmental Geosciences (IGE) and Dartmouth College, the results show the implications on the availability of water for drinking, power generation, agriculture and other uses worldwide. The study also suggests changes in earlier projections on climate-driven sea-level rise. The rise in sea level is expected to affect populations around the globe.
Determining how much ice the glaciers currently hold is a crucial step to anticipate how climate change can affect society, said Romain Millan, a postdoctoral scholar at the Institute of Environmental Geosciences and lead author of the study. He further said that with the acquired information, they will get closer to knowing the size of the biggest glacial water reservoirs and also try to understand how the future world will be with fewer glaciers.
The finding of less ice is important as it will have implications on millions of people around the world. The problem is that even with the currently undertaken research, we still don’t have a perfect estimate of how much water is available in the form of these glaciers.
The new atlas has covered around 98 per cent of the world’s total glaciers and highlights that many of these glaciers are much shallower than was previously estimated in the earlier research. Earlier the glaciers along the borders of Greenland and Antarctica were counted twice, which also played a big role in wayward and inaccurate previous data sets. The current study has found irregular ice distribution with some regions with less ice while more ice in others. But the overall result points to the fact that there is less glacial ice worldwide than was previously thought.
The study discovered that the Andes Mountains has nearly one-fourth less glacial ice than was previously determined. This means that there is around 23 per cent less freshwater stored in an area on which millions of people depend to meet their daily requirements. The researchers estimated that the reduction of this freshwater is equivalent to the drying up of Mono Lake, which is the third-largest lake in California.
Meanwhile, the Himalayan Mountains have been found to have over one-third more ice than what was previously estimated. The result of the research suggested that the availability of water resources in the region could go up by about 37 per cent, despite the continent’s glaciers melting at a very rapid rate. The study undertaken is expected to provide the necessary information for data models, so that they can offer even more reliable calculations of how much time the global glaciers have.
Reason for ice melting
As per various studies, climate change is one of the main causes for the glaciers melting, which in turn aids in rising sea levels. It has been estimated that glaciers contribute to around 25 to 30 per cent of sea-level rise, which threatens around 10 per cent of the world’s population that is living lower than 30 feet above sea level.
Since the available glacial ice was reduced by 23 per cent in the new study, it lowered the potential for glacial contribution to sea-level rise by 3 inches and thus revised the global sea-level rise to 10 inches from the previous 13 inches. The current projection includes contributions from all the global glaciers, other than the two large ice sheets of Greenland and Antarctica, which have an even higher potential contribution to sea-level rise.
According to the research team, the earlier glacial estimates were almost entirely uncertain, due to the lack of ice flow measurements which shows the location of the thick and thin glacier and hence provides for better calculation.
The research team studied more than 800,000 pairs of satellite images of glaciers, including narrow alpine glaciers, slow valley glaciers and fast tidewater glaciers, to create the massive ice flow database. It is generally thought that glaciers are solid ice blocks that melt only in the summers, but ice actually melts under its own weight. The ice flows from higher altitudes to lower altitudes where it eventually takes the form of water.
“Our estimations are closer, but still uncertain, particularly in regions where many people rely on glaciers,” said Millan. “Collecting and sharing measurements are complicated because glaciers are spread throughout so many countries with different research priorities,” he added. He said that without in-field measurements, the estimates of freshwater in glaciers will remain uncertain.
