GEOGRAPHY

Half of the world’s glaciers could disappear by the end of the century


French scientists believe that by the end of the century, human-induced climate change in high-emission scenarios may halve the area covered by the ice sheet outside the Antarctic and Greenland ice sheets. This retreat to 2100 will create new ecosystems covering an area between Nepal and Finland. The study was recently published in Nature.

One of the consequences of climate change caused by human activities is the decline of glaciers, leading to drastic ecological changes and the development of new ecosystems to fill emerging habitats. However, this change has not yet been analysed on a global scale.

Jean-Baptiste Bosson of the Haute-Savoie Nature Reserve in Annezie and colleagues used a global glacier evolution model to study the projected trajectories of 650,000 square kilometers of glaciers beyond the Antarctic and Greenland ice sheets in the 21st century. They used glacier profiles, digital elevation models of the subglacial terrain, and climate data to estimate how each glacier would respond to climate scenarios by 2100. In addition, the model can predict emerging ecosystem characteristics in de-glacial areas, categorized into marine, freshwater or terrestrial categories.

The model expects ice dissipation rates to be similar regardless of climate scenarios until 2040, with differences thereafter depending on the severity of emissions. Under a high-emissions scenario (global greenhouse gas tripling by 2075), half of the glaciers by about 2020 will disappear by 2100. But the low-emissions scenario (net-zero emissions by 2050) would dampen this trend, reducing losses to around 22%.

By the end of the century, the surface area expected to be exposed by ice loss is approximately between Nepal (149,000 ± 55,000 square kilometres) and Finland (339,000 ±99,000 square kilometres), with about 78% terrestrial, 14% marine and 8% freshwater. These areas will provide shelter for cold-adapted species elsewhere that have lost habitat due to warming.

The researchers believe that while limiting ice loss, resources and attention should be provided to protect these newly formed ecosystems to protect their future.

Belveldre glacier ablation area and Mont Blanc hills. Photo by Jean-baptiste Bosson

Herald flowers after the retreat of the Mont Blanc glacier. Photo by Jean-baptiste Bosson

(Source: Feng Weiwei, China Science News)

Related paper information:https://doi.org/10.1038/s41586-023-06302-2



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