World needs to limit global warming to 1.5°C to protect cryosphere, 2°C too high: Report

But both;2°C and 1.5°C could spell doom for permafrost;
Photo: iStock
Photo: iStock
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Nearly all tropical glaciers, most mid-latitude glaciers and polar regions will disappear even if the world manages to limit global temperature rise to 2 degrees Celsius, above the preindustrial era, according to the State of the Cryosphere 2023 report.

The Himalayas are also expected to lose 50 per cent of today’s ice if global average temperatures touch 2°C, the report by the International Cryosphere Climate Initiative, a network of policy experts and researchers working to preserve the Earth’s cryosphere, noted.

The impacts are already being felt at the current temperature rise of 1.2°C as many glaciers of the northern Andes, East Africa, and Indonesia are disappearing rapidly.

The experts call the cryosphere — composed of Earth’s frozen water in ice sheets, sea ice, permafrost, polar oceans, glaciers, and snow — as ground zero for climate change. “From the cryosphere point of view, 1.5°C is not simply preferable to 2°C or higher, it is the only option,” the report read.

“2023 has been a year of climate disasters and ice loss, which has underlined the urgent need for global leaders to recognise that two degrees is too high for Earth’s cryosphere,” Pam Pearson, director of ICCI, said in a statement. “Today’s landmark report shows that we need to take 2°C off the table,” she added.

In October, Sikkim witnessed a flash flood triggered by a glacial lake outburst flood (GLOF) at South Lhonak Lake. GLOF is a catastrophic release of a water reservoir that has formed either at the side, in front, within, beneath, or on the surface of a glacier.

Swiss glaciers lost 10 per cent of their remaining ice over just two years. Sea ice around Antarctica hit an all-time low summer and winter record this year. Water temperatures in parts of the Arctic and North Atlantic were 4-6°C higher than normal, the report highlighted.

Also, the atmospheric carbon dioxide concentrations were 50 per cent above pre-industrial levels in 2023. At 424 parts per million, CO2 concentration was higher than at any point in at least three million years. 

At 2°C, the Arctic Ocean, which historically was covered by sea ice year-round, will be free of sea ice almost every year and for periods of up to four months from July to October. As for Antarctica, experts predicted that it would completely lose sea ice every summer at 2°C.

Further, the Earth’s ice sheets lost 7,560 billion tonnes of ice between 1992 and 2022. The last decade alone has witnessed the seven worst years of ice loss.

Ice sheets in Greenland and parts of Antarctica could contribute between 12-20 metres of sea-level rise at 2°C. This 2°C will result in extensive, potentially rapid, irreversible sea-level rise from Earth’s ice sheets; 3°C will further speed up this loss within the next few centuries, read the report.

Both 2°C and 1.5°C could spell doom for permafrost a ground that stays frozen for two consecutive years. These temperatures, according to the report, are too high to stop the thawing of permafrost extensively. 

When permafrost thaws, it releases CO2 and methane emissions, which will cause a spike in temperatures even if human emissions reach zero. At 2°C, annual CO2 and methane emissions from permafrost emissions are estimated to be comparable to the total size of the entire European Union’s emissions from 2019, the report noted.

The findings come two weeks ahead of the 28th Conference of Parties (COP28) to the United Nations Framework Convention on Climate Change. The authors have called on global leaders to enshrine the commitment to “1.5°C alone” in the Cover Decision because 2°C is too high for the cryosphere. 

“COP28, and December 2023, must be when we course correct. Otherwise, world leaders are de facto deciding to burden humanity for centuries to millennia by displacing hundreds of millions of people from flooding coastal settlements; depriving societies of lifegiving freshwater resources, disrupting delicately-balanced polar ocean ecosystems; and forcing future generations to offset long-term permafrost emissions,” Julie Brigham-Grette, University of Massachusetts Amherst, said in a statement.

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