Between 2001 and 2011, Greenland's ice sheet temperature was 1.5°C warmer than the 20th-century average, making it the warmest decade in the last millennium, according to a study of temperatures on the island. , essential for the global climate.
To carry out the study, whose conclusions were published this Wednesday in the journal Nature, scientists have reconstructed the temperatures in north-central Greenland and the
rates of ice melting between the years 1,100 and 2,100.
Due to its size and the large amount of water it stores (about three million cubic kilometres), the Greenland ice sheet plays a
critical role in the global climate system.
The researchers say that the effects of global warming have reached the remote and elevated areas of north-central Greenland.
For example, if global emissions
are not reduced
, the melting of Greenland is expected to raise the global sea level by 50 centimeters in the year 2100, something catastrophic for the entire Planet.
For years, the meteorological stations located on the edges of this ice sheet (on the coast)
have recorded an increase in temperatures,
but the understanding of the effects of global warming in the center of the island is limited by the lack of observations at long term.
Now, the study published in Nature and led by experts from the Alfred Wegener Institute and the Helmholtz Center for Polar and Marine Research (AWI) presents compelling evidence that the effects of global warming have reached remote and elevated areas of north-central greenland.
"The time series we recovered from the ice cores continuously collects data for more than 1,000 years, from the year 1000 to 2011. These data show that the warming from 2001 to 2011 differs in aspects from the natural variations of the last millennium. Although this was to be expected in light of global warming, we were surprised by how apparent this difference was," says
Maria Hörhold, a
glaciologist at AWI and lead author of the study.
The scientists measured the concentrations of stable oxygen isotopes within the ice
In an unprecedented effort, Hörhold and colleagues
drilled ice cores
from five locations surveyed in the 1990s to reconstruct the ice temperature evolution of north-central Greenland between 1100 and 2011.
The temperatures were reconstructed using a single method: measuring the concentrations of stable oxygen isotopes within the ice, which vary as a function of the prevailing temperatures at the times of ice formation.
In addition, the team also
reconstructed the evolution of the melt.
All this allowed them to collect an important data set with which to improve the understanding of the melting dynamics of the ice sheet and to better calculate projections of future sea level rise.
The study concludes that recent temperatures in north-central Greenland are record high and
the highest in the last thousand years.
On average, the reconstructed temperature for the period 2001-2011 was 1.7 °C warmer than that of the period 1961-1990 and 1.5 °C warmer than that of the entire 20th century.
The authors state that these temperatures are the result of a combination of
natural substitution and climate warming
initiated in the 18th century by human activity, and that this warming has caused a thaw in north-central Greenland that may increase as more ice is lost from the cap.
Finally, they conclude that the climate of the Greenland ice sheet is very
disconnected from the rest of the Arctic
"which has shown to have its own dynamics", defends Thomas Laepple, AWI researcher and co-author of the work.
Map with the location of the Greenland ice cap, its extension in 2008 and the estimate for the year 2300 - AFP / AFP
The authors believe that Greenland's own dynamics are due to the fact that the height of the island's ice sheet is more affected by
patterns than other parts of the Arctic.
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