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Sixty years ago, Doctor James Lahey, my meteorology professor, closed our final class of the year by cautioning us to monitor the arctic sea ice limits as an indicator of climate change.

Every year, the southern limit of the ice pack in the Bering Sea is recorded, and the northern meltback to which it shrinks is also observed. Similar records are collected all around Earth’s polar waters.

The urgency of the situation is clear. Measurements since 1980 show the annual area of the sea ice to be shrinking by about 17,000 square miles per year. Another way to think of it is that since Earth Day in 1970, we have lost nearly a million square miles of seasonal sea ice coverage. This rapid loss of sea ice is not just a statistic, it's a call to action. But who cares?

We should all care. Understanding the phenomenon of albedo is crucial to comprehending the impact of melting sea ice on climate change. A perfect mirror has an albedo of 100%, and everything shining on it is reflected.

Sea ice, generally covered with snow, has an albedo in the eighty to ninety percent range. On the other hand, open arctic seawater absorbs most of the sunlight that shines on it, giving it an albedo of about 10%. This means that our earth is seasonally absorbing at least seventy percent more solar energy in a million square mile area than it did in the 1960s.

Each year, because the sea water is warmer than the year before, having absorbed more sunlight in the previous summer, the ice area shrinks some more. This is a positively reinforcing feedback loop, which will be very difficult to reverse.

We’ve all seen videos of polar bears starving because they need sea ice on which to hunt seals. We see Alaska Natives having to move away from the shores that are no longer protected by sea ice. Perhaps you have seen clips of cargo ships testing the legendary Northwest Passage.

All of these are evidence of that feedback loop moving the open water further poleward. There are studies on increasing the albedo of our polar oceans, but the scale is enormous. How do we cover a million square miles with something less absorbent and environmentally damaging?

Fortunately, we only have to cover part of that area to reverse the loop, yet the numbers are still enormous and not feasible with any current technology. Recent studies suggest that if we lower our overall global temperature a few degrees the ice loss may be reversed in as little as 10 years. They also indicated that there isn’t an irresistible tipping point that would keep us from losing sea ice no matter what.

What can we do about it? We have the power to make a difference. If we can lower our planet’s average atmospheric temperature, the oceans will also cool. Here are some practical steps you can take: burn less fuel and consume less electricity, perhaps by lowering your thermostat a degree or two or switching to more efficient HVAC, lights and appliances. Every small action counts.

Charlie Parson is a member of the Citizens' Climate Lobby organization. For more information, visit