Sea Ice and Polar Bears

11/10/2011 6:30:05 PM

Sea Ice and Polar Bears

We headed out early in Tundra Buggy® One this morning to make webcast presentations today, the first one with my own class back home with graduate students in atmospheric sciences at the University of Washington. In the beautiful early morning light, I spotted a mother and one-year-old cub about 30m (100 feet) off. We paused for 30 minutes and watched them until they wandered off. We continued our journey to the Tundra Buggy Lodge where we positioned ourselves for the day's presentation.

Consolidated sea ice is nowhere to be seen on the shore here. There is a little frazil or grease ice growing, but it's too slushy to hold the weight of a polar bear. It will take another week at least at these air temperatures for the slush to consolidate. Sea ice doesn't ever freeze solid at the temperatures typical in the Arctic. Instead, it's porous because some of the salt from the ocean is trapped inside. The pores house algae and other microorganisms that are part of the marine foodweb. So sea ice is not just a physical platform, it's an integral part of the ecosystem. Sea ice typically does not cover 100% of the ocean anywhere. There's normally open water in breaks between floes or plates of ice. The map of Hudson Bay shows how different current conditions are this November from normal. The red colors indicate below average concentrations are pervasive.

At present there is sea ice covering a portion of the Arctic Ocean all year, although Hudson Bay has historically been ice-free in summer. My research involves predicting the future of Arctic sea ice. We project there will be no sea ice anywhere in summers before the end of this century. There is large uncertainty in exactly when the Arctic Ocean will be ice-free, but there is a good chance it will occur by mid-century if humans continue to emit greenhouse gases unabated. We can all help by conserving and changing to renewable energy. If all humans emitted greenhouse gases evenly and at a level to avoid supposed dangerous warming (2 degrees Celsius), we in the developed world need to cut our average emissions by 1/5. Mandatory regulation and the technology it would stimulate is the only answer.

When I began to research the global warming problem in the early 1990s, I did not recognize the sense of urgency at first. I even drove an SUV in those years. I pursued the problem because I found it intellectually challenging. Since then the evidence has grown so compelling in such a short time that I now feel very different about it. I drive a compact car and mostly bicycle now. The loss of Arctic sea ice and its affect on polar bears keep me awake at night: quite literally as it's now after midnight and I'm  blogging and preparing my talk for the lodge guests—even though we have another early start tomorrow.

The wind is blowing just enough to cause the buggy lodge to sway gently like a cradle. I'm also thinking about the beautiful female bear that lay in our buggy's path for a long while. I have included a close-up of her thin body. She should be covered in fat in preparation for the cold months. It's doubtful she can raise pups this spring with such poor condition now. I'm grateful to her for making us slow down. What a perfect end to a magical but sobering day.

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