Declassified Images Reveal Extreme Arctic Ice Melt

Above: Beaufort Sea images, showing retreat of sea ice between 2001 and 2006. More info below.

Just hours after a mid-month request from the National Research Council, the Department of Interior released over one thousand spy images of the Arctic and other locations in the US. The Bush administration had classified the images and kept them from the public and federal scientists.

The newly declassified images document such a startling retreat of Arctic sea ice, that the UK's Guardian newspaper calls them "the secret evidence of global warming Bush tried to hide":

The pictures, kept secret by Washington during the presidency of George W Bush, were declassified by the White House last week. President Barack Obama is currently trying to galvanise Congress and the American public to take action to halt catastrophic climate change caused by rising levels of carbon dioxide in the atmosphere.

One particularly striking set of images - selected from the 1,000 photographs released - includes views of the Alaskan port of Barrow. One, taken in July 2006, shows sea ice still nestling close to the shore. A second image shows that by the following July the coastal waters were entirely ice-free.

The photographs demonstrate starkly how global warming is changing the Arctic. More than a million square kilometres of sea ice - a record loss - were missing in the summer of 2007 compared with the previous year.

Nor has this loss shown any sign of recovery.

Here's the image that the Guardian's talking about:

Kudos to Julia Whitney at the Mother Jones Blue Marble blog, Dan Vergano at USA Today's Science Fair blog, and Deborah Zabarenko at Reuters, for being right on top of this story earlier in July. As Zabarenko notes, the images are at a resolution of 1 meter, an enormous improvement over earlier images with resolutions of 15 to 30 meters.

"These are one-meter resolution images, which give you a big picture of the summertime Arctic," Thorsten Markus of Nasa's Goddard Space Flight Center told Reuters. "This is the main reason why we are so thrilled about it. One-meter resolution is the dimension that's been missing."

Especially given the failed late Feburary launch of NASA's Orbiting Carbon Observatory (it crashed into the Southern Ocean a few minutes after takeoff, due to rocket failure), these images should be an enormous boon to researchers trying to figure out how fast global warming is progressing, and better understand what the future might look like.

Whitney writes,

The higher definition pictures reveal small features with big impacts on warming—like dark melt pools on top of the ice that absorb light and heat. These images will vastly improve the accuracy of forecast modelling.

Scientists were expecting the request for the Arctic images to be declassified to take months—at least.

But apparently someone in Washington digs science and actually understands something about climate security and the perils of thin ice.

The Arctic ice cap plays a major role in regulating the global climate. Without that ice reflecting the sun's heat back into space (an effect that's called albedo), the heat is instead absorbed by the water, which in turn melts more ice, which leaves more open water to absorb more heat, and so on. (Dr. Mark Serreze, the director of the National Snow and Ice Data Center, recently called this an Arctic ice death spiral.) All of which is contributing to raising the average surface temperature of the entire Earth.

That ice is also crucial habitat for polar bears, walruses and Arctic seals. Without it, it seems likely they would ultimately go extinct in the wild.

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Images courtesy US Geological Survey

At top of screen:

Beaufort Sea - 73N, 150W

This region has been the site of many field studies since the International Geophysical Year 1957/58. The ice in this region is the most studied and best known. It has been the locale of many studies of the surface heat budget, as well as submarine sonar cross sections.

Arctic ice is retreating; a trend overlain with considerable year to year variability. This site is near the edge of the ice pack. In the 24 hour darkness and cold of winter, any open water freezes quickly. In summer, as shown here, ponds of meltwater form on the surface. These dark pools absorb more of summertime's solar radiation than does the surrounding ice, enhancing melting. Pond coverage monitored over time contributes to estimates of surface reflectivity that are needed to model the response of sea ice to changing climate.