Earth losing ice at record speed

Earth losing ice at record speed

Such predictions could in turn be used by communities around the world to better prepare for flooding and mitigate coastal ecosystem damage.

Scientists still are investigating the sources of the warm water, but some experts believe climate change is altering ocean currents in ways that may be driving more melting. By measuring their fjords one by one, a new study published in Science Advances has quantified, for the first time, how the warming coastal waters are impacting Greenland's glaciers.

Half of all losses were from ice on land, and raised global sea levels by 35mm. Every single glacier region around the world lost ice.

"Isobel Lawrence, a fellow researcher, explains", sea ice loss doesn't contribute directly to sea-level rise but has an indirect influence.

"I was surprised by how lopsided these findings were".

In the case of Greenland's glaciers, the bigger they are, the faster they melt.

The glaciers were being affected by a process known as "undercutting". The ice in Greenland is more than two miles (three kilometers) thick in places.

Despite storing only 1 % of the Earth's total ice volume, glaciers have contributed to nearly a quarter of the global ice losses over the study period, with all glacier regions around the world losing ice.

Additionally, the melting accelerated the fastest for the Greenland and Antarctic ice sheets, the research found. The ice is replenished by snowfall that is compressed over time into the ice pack. At the edges of the land mass, the vast glaciers extending from the ice sheet travel slowly down valleys like icy conveyor belts, which inch into the fjords and then melt or break off as icebergs.

The research, funded by UK Natural Environment Research Council, shows that overall, there has been a 65 % increase in the rate of ice loss over the 23-year survey.

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If the ice sheet were in balance, the amount of snow accumulating on the top would roughly equal the ice lost from melt, evaporation and calving - chunks breaking free from anchored masses and floating off into the ocean. But as the ice shelves shrink, they destabilize the ice sheet's glaciers and contribute to further losses. Meanwhile, an ongoing NASA mission has revealed that the warming oceans play a dominant role in melting Greenland, too. During the summer months, increasing air temperatures heat the glacier's surface, creating pools of meltwater. This liquid passes through the broken part of the ice, forming a body of water that flows back to the sea.

Glacial meltwater doesn't contain salt, so it is less dense than saltwater and thus rises as a plume.

But Sverdrup also represents a large class of Greenland glaciers that are undergoing rapid retreat in response to warm ocean water.

The position in 2000 was similar to the mid-1980s, indicating that there had been a period of stability when ocean temperatures were cool.

Slater continued, "The ice sheets are now following the worst-case climate warming scenarios set out by the Intergovernmental Panel on Climate Change".

The study also lends insight into why many of Greenland's glaciers never recovered after an abrupt ocean warming between 1998 and 2007, which caused an increase in ocean temperature by almost 2 degrees Celsius.

Dr. Slater said the study was the first of its kind to examine all the ice that is disappearing on Earth, using satellite observations.

While such ice loss does not directly contribute to sea rises, its destruction does stop the ice sheets reflecting solar radiation and thus indirectly contributes to rising sea levels. By subscribing, you can help us get the story right.

Main picture: To measure water depth and salinity, the OMG project dropped probes by plane into fjords along Greenland's coast.

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