The study, published in the journal "Science", presents the most accurate predictions reached to date regarding the future of the 215,000 glaciers in the world, as half of the world's glaciers, and specifically the smallest among them, face the risk of disappearance by the end of this century.
Half of the world's glaciers, particularly the smallest, are at risk of disappearing by the end of this century due to climate change, but limiting climate warming as much as possible helps save other rivers, according to a recent study published Thursday.
This study, published in the prestigious "Science" magazine, presents the most accurate predictions that have been reached to date regarding the future of 215,000 glaciers in the world.
Its authors warn of the importance of taking steps to reduce greenhouse gas emissions responsible for climate change, with the aim of limiting the melting of glaciers and its consequences, such as rising sea levels and a shortage of water resources.
"I think our study carries a small glimmer of hope and a positive message, because it confirms that humans can make a difference and that taking action to solve this issue is important," study co-author Regine Hook told AFP.
The study touched on the direct impact of climate warming within several possible scenarios (+1.5°C, +2°C, +3°C, +4°C) on glaciers, in order to better guide political decisions.
If global warming is limited to 1.5°C above pre-industrial levels, the most ambitious target of the Paris climate agreement, 49% of the world's glaciers will be gone by 2100.
This loss represents about 26% of the total glacier mass, because warming will harm smaller rivers first. The researchers expect the sea level to rise as a result of the melting of ice to about 9 centimeters (a height that will be added to that associated with the melting of the ice caps, for example).
"Regions with relatively little ice, such as the Alps, the Caucasus, the Andes, or the western United States, will lose almost all of their ice by the end of the century, regardless of the potential associated with emissions," Regine Hook said, adding that "these glaciers are threatened in one way or another with extinction.
In the event of climate warming of +4 °C, the worst-case scenario would occur, as larger glaciers such as those in Alaska, for example, would be affected by increasing amounts. And 83% of the glaciers will disappear, or 41% of the total ice mass in the world, while the sea level will rise to 15 centimeters.
Regine Hook, who devoted her career to studying glaciers, notes, in an interview with Agence France-Presse, that "9 centimeters and 15 centimeters may not seem like big numbers, but these two levels are a cause for great concern," because the higher the sea level, the higher it causes large floods during storms, causing "more damage".
The world is already witnessing severe floods as sea levels rise (3 millimeters per year).
Complete demise of glaciers
The world is currently heading towards a warming of +2.7°C, which will lead to the almost complete disappearance of ice sheets in central Europe, western Canada, the United States, and New Zealand.
These more alarming projections than those of the Intergovernmental Panel on Climate Change are made thanks to recent data on changes in the size of every glacier in the world over recent decades. Based on this data, the researchers were able to better reset the computational model used to predict the future of rivers.
Also, factors that were not addressed in previous studies were taken into account, including the effect of covering glaciers with debris (rocks...), or the detachment of ice blocks from icebergs.
The glaciers studied represent only 1% of the world's total ice, but they are affected more than other glaciers, because they are often located in areas where temperatures are close to those on which the ice melts.
Hook notes that these glaciers "have contributed almost as much to rising sea levels as the melting of the ice caps in Greenland and Antarctica over the past three decades."
Therefore, the water resources that benefit about two billion people will be affected by the disappearance of the glaciers.
The researcher points out that "glaciers would fill the water shortage that many regions witness during the summer when they are exposed to heat and drought," adding that the disappearance of the rivers "will not only cause a change in the seasons (...) but will also cause a decrease in quantities of water." water.”
Also, boat traffic in low-lying rivers and tourism activities around small, easily accessible glaciers will be affected.
Regine Hook asserts that avoiding the disaster is still possible, but that "its occurrence is linked to political officials."
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