Half a degree Celsius can mean the world for Arctic animals

The Arctic Ocean stays in the headlines with its continuous loss of sea ice. According to the new study, the probability of ice-free summers or not depends on half a degree Celsius. Thus, polar bears depend on the goodwill of the world leaders to fulfill their climate goals. Credit: Michael Wenger

The difference between life and death usually is a thin line. The same goes for the very existence of Arctic sea ice and all the animals which depend on it, according to a new study by a researcher from the University of Colorado. Her analysis shows that already half a degree more of climate warming will lead to a more certain ice-free Arctic ocean in the future.

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When greenhouse gases start wandering

To investigate the melt ponds on sea ice, the scientists are forced to make camp on the sea ice, close by to the icebreaker “Polarstern”. Credit: Marcel Nicolaus

On the seafloor of the shallow coastal regions north of Siberia, microorganisms produce methane when they break down plant remains. If this greenhouse gas finds its way into the water, it can also become trapped in the sea ice that forms in these coastal waters. As a result, the gas can be transported thousands of kilometers across the Arctic Ocean and released in a completely different region months later. This phenomenon is the subject of an article by researchers from the Alfred Wegener Institute, published in the current issue of the online journal Scientific Reports. Although this interaction between methane, ocean and ice has a significant influence on climate change, to date it has not been reflected in climate models.

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Weather anomalies help to melt Arctic sea ice

Large parts of the Arctic Ocean are covered with sea ice every year. While in former days, the ice stayed all year round, it nowadays disappears in many areas in summer and reforms in winter. Credit: Michael Wenger

The melting of Arctic sea ice during the winter of 2015/16 had received immense media attention. Several causes had been debated and many saw global climate change as the main culprit. But now, researchers at the ETH Zurich found unique weather anomalies to be the main causing factor. Yet, the researchers have not given an all-clear-signal.

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Arctic data shows no warming hiatus

The global warming hiatus, an apparent global warming slowdown, has puzzled scientists for a long time. Instead of an ever-rising temperature, the average global temperature seemed to go down again. New data from the Arctic, however, shows that the Arctic actually warmed six times faster than the global average and that global warming in fact didn’t slow down at all.

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Further decrease of Arctic sea ice measured

This September, the extent of Arctic sea ice shrank to roughly 4.7 million square kilometres, as was determined by researchers at the Alfred Wegener Institute, the University of Bremen and Universität Hamburg. Though slightly larger than last year, the minimum sea ice extent 2017 is average for the past ten years and far below the numbers from 1979 to 2006. The Northeast Passage was traversable for ships without the need for icebreakers.

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How the climate can rapidly change at tipping points

During the last glacial period, within only a few decades the influence of atmospheric CO2 on the North Atlantic circulation resulted in temperature increases of up to 10 degrees Celsius in Greenland – as indicated by new climate calculations from researchers at the Alfred Wegener Institute and the University of Cardiff.

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Record low of Arctic sea ice in winter

In 2012, news about the record low of Arctic sea ice minimum extent went around the world. Now, the Arctic sea ice maximum extent also has reached an all-time record low according to the data presented by the US National Snow and Ice Data Center in Boulder, Colorado. A mere 14.4 million square kilometers of the Arctic Ocean were covered by ice.

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Extreme heating in the Arctic in 2016

2016 will be remembered for many things, one of them being the heat. Globally, it was the hottest year since instrumental records began, but Arctic temperatures during 2016 were truly exceptional. As the year drew to a close, the high-latitude Arctic was blistered with extended periods of record-breaking heat. Surface temperatures during October–December were, on average, ~5 °C above expected in an area spanning the Arctic Ocean, from Greenland across the North Pole to far eastern Russia.

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Where has the sea ice gone?

In many areas, winter still hasn’t settled in and snow and ice are rare sights. In the north, unusually high air temperatures and a warm ocean have led to a record low Arctic sea ice extent for November, according to scientists at the National Snow and Ice Data Center (NSIDC) at the University of Colorado Boulder. In the Southern Hemisphere, Antarctic sea ice extent also hit a record low for the month, caused by moderately warm temperatures and a rapid shift in circumpolar winds.

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How each one of us contributes to Arctic sea ice melt

The rapid retreat of Arctic sea ice is one of the most direct indicators of the ongoing climate change on our planet. Over the past forty years, the ice cover in summer has shrunk by more than half, with climate model simulations predicting that the remaining half might be gone by mid-century unless greenhouse gas emissions are reduced rapidly. However, a number of studies have indicated that climate models underestimate the loss of Arctic sea ice, which is why these models might not be the most suitable tools to quantify the future evolution of the ice cover. A new study explains the underlying issues and allows for the first time to calculate individual contributions to Arctic's shrinking sea ice.

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