Glaciers Are Retreating At A Faster Pace Globally

Globally the retreat of glaciers have accelerated, according to a latest study published in the peer-reviewed journal Nature. Glaciers are slow moving mass of ice over land, and are sensitive indicators of climate change.  

Scientists currently have only a limited understanding of the extent of the melting of glaciers. An international research team led by ETH Zurich and the University of Toulouse has authored a comprehensive study on global glacier retreat. This is the first study to include all the world's glaciers - around 220,000 in total - excluding the Greenland and Antarctic ice sheets.

The study shows how rapidly glaciers have lost thickness and mass over the past two decades. Between 2000 and 2019, the world's glaciers lost a total of 267 gigatonnes (billion tonnes) of ice per year on average - an amount that could have submerged the entire surface area of Switzerland under six metres of water every year. This glacial melt caused up to 21 percent of the observed rise in sea levels during this period - some 0.74 millimetres a year.

The world temperature has continued to rise in recent decades with 2020 being among the three warmest years on record.

Worrying situation in the Himalayas

Among the fastest melting glaciers are those in Alaska, Iceland and the Alps. The situation is also having a profound effect on mountain glaciers in the Pamir mountains, the Hindu Kush and the Himalayas. 

"The situation in the Himalayas is particularly worrying," explains Romain Hugonnet, lead author of the study and researcher at ETH Zurich and the University of Toulouse. "During the dry season, glacial meltwater is an important source that feeds major waterways such as the Ganges, Brahmaputra and Indus rivers. Right now, this increased melting acts as a buffer for people living in the region, but if Himalayan glacier shrinkage keeps accelerating, populous countries like India and Bangladesh could face water or food shortages in a few decades." 

Climate change has already altered water flow in the Himalayan region that has the largest mass of frozen water outside the two poles, as Forbes reported earlier. In recent years there have been increasing number of extreme events in the region like avalanche too due to the changes.

Areas where glacial melt slowed down

The researchers also identified areas where melt rates slowed between 2000 and 2019, such as on Greenland's east coast and in Iceland and Scandinavia. They attribute this divergent pattern to a weather anomaly in the North Atlantic that caused higher precipitation and lower temperatures between 2010 and 2019, thereby slowing ice loss.

The findings of this study can improve hydrological models and be used to make more accurate predictions on a global and local scales - for instance, to estimate how much Himalayan glacier meltwater one can anticipate over the next few decades.

"Our findings are important on a political level. The world really needs to act now to prevent the worst-case climate change scenario," says co-author Daniel Farinotti, head of the glaciology group at ETH Zurich and the Swiss Federal Institute for Forest, Snow and Landscape Research WSL.