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Greenland ice can no longer handle hot summers



One person watches Greenland's ice during a 2017 NASA campaign.
Photo: NASA

A team of scientists warns that the double blow of a naturally recurrent weather and rising temperatures triggers a dramatic melt Greenland ice – a problem the researchers compare with the recent global coral bleaching events caused by the double victory of El Niño and climate change were fueled.

The study published Monday in the Proceedings of the National Academies of Sciences, examined the decline of the giant ice sheet in the north from 2003 to 2016 based on data from NASA's Gravity Recovery and Climate Experiment (GRACE) satellite and a network collected from GPS stations. Over the course of a decade, scientists documented a fourfold acceleration of the ice mass lost in Greenland from 102 billion tons per year in 2003 to 393 billion tons per year in 2013. Then suddenly something was causing Greenland to pause. The ice losses almost stopped for 12 to 18 months before accelerating again.

This was, according to the researchers, the North Atlantic Oscillation (NAO) – a natural atmospheric cycle that affects the weather in a wide region, oscillating between positive and negative. Positive phases of the NAO lead to above-average cool temperatures in Greenland, while negative phases are associated with warmer summers and less snowfall, especially in West Greenland. From 2003 to 2013, the NAO became increasingly negative, a trend that researchers noted in the context of an acceleration in the amount of meltwater draining from southwest Greenland. Then the NAO made a brief and dramatic upset and collapsed with the ice-break break before turning negative again.

This is important for a few reasons. On the one hand, the Greenlandic sensitivity to the NAO shows how fragile ice is for a slight increase in air temperatures, a finding that clearly shows a time when the Arctic is warming up incredibly fast.

In addition, research shows how natural the cycle associated with human-induced warming is causing large ice losses today.

"These oscillations have happened forever," said lead author Michael Bevis of Ohio State University in a statement. So why are they causing this massive melt now? The atmosphere is warmer at the baseline. The temporary warming that was driven by the North Atlantic Oscillation was due to more sustainable global warming. "

The researchers are analogizing to the effects of El Niño – a natural environmental climate that, on average, results in warmer waters Equatorial Pacific influence weather around the world – has accumulated on global warming in the oceans, with devastating consequences for the coral reefs of the planet. Global coral bleaching events in 1998, 2010 and 2016 all coincided with the years of El Niño, but as the scientists of the coral reef repeated ad nauseam these events also show fingerprints of climate change.

El Niño just did not do that There is no juice to cook reefs around the world unless the global background temperatures rise. The same can now apply to negative NAO years, and ice pearls melt on Greenland's surface.

This is not the first recent study to show the precarious position of the ice of our planet. A study published in December in Nature showed that the melting rates on Greenland's surface have risen in recent years, and warned that a "non-linear response" to rising summer air temperatures will cause melting to accelerate even more in the future , If all of Greenland's ice melted – a scenario that sounds extreme but could have happened in the not so distant past – global sea levels would rise by almost 25 feet.

Mountain glaciers disappear as well. In the western United States and Canada, these small but regionally significant chunks of ice melt four times faster than they did a decade ago, according to a recent study from Geophysical Research Letters. Then, at the end of the world, there is the Great Kahuna – nearly 200 meters of global sea-level rise, trapped in the cold deserts of the eastern Antarctic. A study published in Nature published last week in Nature suggested that even this hardened fortress is beginning to weaken.

We still have time to prevent a nightmare scenario from happening, but the steady eardrum of research showing the icy landscapes of Earth in limbo reminds us that the clock is ticking.


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