114.6.21(六)Samedi 21 juin 2025
Regardless of climate mitigation strategies,
the world’s glaciers are on track to shrink significantly over hundreds of
years, according to a new study published Thursday.
Even if global temperatures stayed where
they are today for the next 1,000 years, essentially an impossibility, glaciers
outside of ice sheets would lose roughly one-third of their mass, researchers
estimated.
But there’s still hope to avoid the most
severe losses, the assessment said. Limiting warming to 1.5 degrees Celsius, or
2.7 degrees Fahrenheit, above the preindustrial average could save about twice
as much ice in a millennium than if the planet warmed by 2.7 degrees Celsius,
the trajectory the world is currently on for 2100, according to the study.
‘’Every tenth of a degree less of warming will
help preserve glacier ice,” said Lilian Schuster, a glacier modeler at the University
of Innsbruck in Austria who helped lead the research, which was published in
the journal Science.
The massive ice sheets that cover Antarctica
and Greenland get a lot of attention in the climate change discussion; if they
melted, sea levels would rise more than 200 feet, flooding coastal cities around
the world.
But glaciers found in mountains and near
the margins of ice sheets play a small but significant role in the climate
change story, too. They make up less than half 1% of the world’s ice and, if
they melt, they would contribute about 1 foot to global sea lever rise.
Using eight different glacial models, the
researchers analyzed how more than 200,000 of the world’s glaciers would respond
to 80 different climate scenarios, over thousands of years.
Even if warming stops at 1.2 degrees Celsius
above preindustrial levels, the average warming over roughly the last decade,
glaciers are on track to lose significant volumes of ice within a millennium, the
study found. The median ice loss was about 40%, which would add about 10 centimeters
to sea level rise.
Because the planet has already warmed at least 1.2 degrees Celsius, that ice loss and its resulting sea level rise are unavoidable. (Rebecca DFzombak)
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