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ice sheet and penguins are threatened by the increase in rains

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A study assessed how liquid precipitation changes in Antarctica with the global warming. The recently published results show a worrying increase in the occurrence of rain, both for the ice sheet and for some penguin colonies.

When one thinks of Antarctica, the usual reflex is not to imagine a landscape battered by rain. Indeed, in addition to being particularly cold, the continent is extremely dry – it is in fact the largest desert on the planet. However, the coasts experience a few days of liquid precipitation per year. A figure that even rises more than 50 days northwest of the Antarctic Peninsula.

The rain takes its ease in Antarctic

However, with global warming, these rains are expected to become more frequent and more intense. This is what the work of a group of European researchers, published in the journal Geophysical research letters March 27. If the climate continues to change at the same rate, we expect an average increase in liquid precipitation of 240% continent-wide.

“Overall, that the rain is increasing in a warming climate shouldn’t come as a surprise, but the extent to which it is happening on such a cold continent is interesting,” notes Richard Bintanja, meteorologist of theUniversity of Groningen (Netherlands) who did not participate in the study.

Climatology of rainy days under positive temperature between 1995 and 2014 according to two models (a, c). Future variations calculated as the differences between the climatology 1995-2014 and that of 2081-2100 (b, d). On the right column, the blue colors indicate an increase. Credits: It is. Vignon et al. 2021.

Also, the simulations show that the rain does not progress towards the interior of Antarctica in a homogeneous way. For some areas, the rain / snow limit hardly changed between the recent period and the end of the century. For others, it gains up to 1000 kilometers on frozen ground. The Ross and Filchner-Ronne ice barriers – the largest in the world – are particularly exposed.

A great threat to penguins

These changes are of course not without consequences, both for the ice sheet and for the local environment. Thus, the melting of the continental ice would take place at an accelerated rate while the baby penguins exposed to the drops of water would be easily decimated as soon as the cold returned. A terrible fate which is reminiscent of the episode observed during the winter of 2013-2014 when all the chicks in an Adélie colony died of hypothermia. And for good reason, their feathers are not waterproof. A world with more rain therefore poses a serious threat to penguins.

Given the increasing importance of precipitation for the Antarctic climate, these differences call for more attention to assess and improve the representation of the microphysics of precipitation and water phases in climate models in the world. over Antarctica », Says the paper in its conclusion.



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