In The Last Three Years Antarctica Lost Ice the Size of Greenland

Global climate change is manifesting itself in many ways around the world. From hotter than hot summers to intensifying tropical storms, the climate crisis is ongoing. As the world tries to adjust to ever changing realities, researchers are working hard to gather data and make sense of it in time to understand the root of what is going on.

One of the challenges our warming world is facing is the melting of glaciers, ice caps, and sea ice. The biggest stores of ice on land and on the sea are melting at faster rates than have ever been recorded. A recent report published by the Proceedings of the National Academy of Sciences analyzed satellite data that showed Antarctica’s rapid sea ice decline; the data showed that ice roughly the equivalent of Greenland (the largest island in the world) has melted over the last three years.


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Antarctic Sea Ice Retreats

This study showed a reversal of data gathered on the Antarctic continent from 1979-2014. In those years, satellite data showed that the amount of sea ice was growing. Unfortunately, between 2014 and 2017, 2.1 million square kilometers (or 810,815 square miles) melted. The Antarctic saw its 40-year record high ice pack in 2014 and experienced its lowest amount of sea ice in 2017.

The Antarctic has now caught up with the Arctic, which is also melting at an alarming rate. In four years, Antarctica has lost as much sea ice pack as the Arctic lost in 34 years. Although these changes may not be related to global warming, they can influence global temperature. Sea ice reflects 50-70% of sunlight back into space, while darker ocean water absorbs 90% of that light and heat.

Changes in the Antarctic ice sheet’s contribution to global sea level, 1992 to 2017. Credit: IMBIE/Planetary Visions. Graph source: NASA

Changes in the Antarctic ice sheet’s contribution to global sea level, 1992 to 2017. Credit: IMBIE/Planetary Visions. Graph source: NASA

The Future of the Ice

Researchers are unsure as to whether or not the loss of sea ice will continue, or if there will be another reversal and the Antarctic continent will begin to build its stores of sea ice again. There was a rapid melting period observed in the 1970s, which then led to an expansion of sea ice a few years later.

There are a few factors that influence these changes in the Antarctic. In addition to global warming, sea ice is also influenced by global weather patterns. There is a pattern of westerly winds that surrounds Antarctica that dissipates some of the immediate effects of the overall global temperature. Additionally, the amount of melting water coming off of the surface ice of Antarctica can influence how much sea ice melts or refreezes over the course of a year.

Scientists will continue to study the Antarctic and monitor changes in sea ice, just as they observe the changes in habitat for the animals that depend on the ice for food and shelter.

Reference

Parkinson, C. L. (2019). A 40-y record reveals gradual Antarctic sea ice increases followed by decreases at rates far exceeding the rates seen in the Arctic. Proceedings of the National Academy of Sciences, 116(29), 14414-14423. https://doi.org/10.1073/pnas.1906556116 

Rosane, Olivia. Antarctica lost sea ice four times the size of France in three years. July 5, 2019. Retrieved from https://www.weforum.org/agenda/2019/07/antarctica-lost-sea-ice-4x-the-size-of-france-in-3-years

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