Consequently, our planet is absorbing more solar energy

Feb 20, 2014 21:06 GMT  ·  By

According to a new paper in the journal Proceedings of the National Academy of Science, the Arctic is now darkening at a fairly rapid pace. As a result, our planet is losing its reflectivity, and starting to absorb more solar energy than it used to.

Besides, scientists say that, as shown by recent investigations, the darkening of the Arctic has a greater impact on the Earth's reflectivity than previously assumed.

Researchers with the University of California, San Diego explains that, when compared to the 1970s, the Arctic is now about 3.6 degrees Fahrenheit (2 degrees Celsius) warmer.

What's more, the summer minimum Arctic sea ice extent is roughly 40% smaller than it used to be just four and a half decades ago.

This basically means that the sea ice is steadily melting and being replaced by the ocean surface.

The trouble is that, whereas sea ice is white and bounces a considerable amount of sunlight back into space, the ocean surface is dark, and therefore cannot do such a thing.

Consequently, the Arctic region's albedo, i.e. the fraction of light that is reflected, is steadily decreasing, and the planet is gradually starting to absorb more solar energy.

According to the University of California, San Diego researchers, the albedo of the Arctic region dropped from about 52% to 48% between 1979 and 2011.

“It's fairly intuitive to expect that replacing white, reflective sea ice with a dark ocean surface would increase the amount of solar heating,” says graduate student Kristina Pistone, as cited by NASA.

“Scientists have talked about Arctic melting and albedo decrease for nearly 50 years. This is the first time this darkening effect has been documented on the scale of the entire Arctic,” adds climate scientist Veerabhadran Ramanathan.

Specialists estimate that heating linked to Arctic ice loss-induced albedo changes is about one fourth as large as heating caused by higher atmospheric carbon dioxide concentrations documented during the same time span.