Darker Arctic Contributing to Global Warming

Global warming

Darker Arctic waters, revealed as a result of melting snow caps. are contributing to global warming. This finding was shared as part of the Proceedings of the National Academy of Sciences. The continued melting of polar snow caps is a well-documented phenomenon, with grassroots environmental action group Natural Resources Defense Council (NRDC) confirming NASA’s finding that the extent of the polar icecap was the sixth lowest of all time. Over the course of a decade, the Arctic has lost over 432,000 square miles (1.12 million square kilometers) of ice as compared to the average between 1981 and 2010. The white, reflective surface of the Arctic icecap is believed to be responsible for the reflection of sunlight back into space. The decrease in this reflective surface is believed to cause more heat to be trapped in the atmosphere, perpetuating the cycle of global warming.

In a study published by researchers at the Scripps Institution of Oceanography in California, dark Arctic waters are reportedly contributing to global warming. The extent of this phenomenon has been measured in terms of the reflectivity of Arctic snow. The study indicates that measurements of the reflectivity of sunlight by the Arctic icecaps have declined by about 8 percent in a measurement period between 1979 and 2011 accounting for over 6.4 W/m2 of solar energy that has been absorbed by the oceans during the period. Despite the cyclic replenishment of snow, climatic changes across three decades have reduced the albedo value of arctic snow from 52 to 48 percent. Professor Veerabhadran Ramanathan, director of the Center for Atmospheric Sciences at the Scripps Institution of Oceanography, said that although scientists have been talking of the Arctic melting and the albedo decreasing for close to 50 years, this is the first time that the darkening has been seen on a scale that encompasses the entire Arctic.

Satellite images from NASA confirm the gradual reduction in the area of the polar ice cap. Atmospheric scientists at the Goddard Institute of Space Studies and the Earth System Science Interdisciplinary Center of the University of Maryland have confirmed the existence of a high-pressure wind system in the center of the Arctic that causes a compacting of the ice shelf and results in clear skies that accelerate the melting of the Arctic snow cap.

Researchers at the Geological Survey of Denmark and Greenland who have been investigating ice sheet sensitivity to weather and climate have also confirmed the findings of the Scripps team. They explain that the melting of Arctic icecaps allows more sunlight to warm the waters of the Arctic Ocean and slow down the reformation of ice during the fall and winter months. This process is said to hamper the cycle of shrinking and expanding of the Arctic ice cap and will result in increased ocean and air temperatures. As scientists grapple with the ramifications of dark Arctic waters contributing to the increase in global warming, climate change experts continue to call for increased dialogue and action by world governments to reduce the emission of ozone-eroding greenhouse gases on a planetary scale—perhaps the last hope left for the planet.

By Grace Stephen




Southern California Public Radio

CBC News