The Melting Snowball Effect

A new look at twenty years worth of research shows that polar ice is in fact melting, and raising sea levels, faster than anticipated. Greg Laden writes “Greenland is losing ice about 500% faster now than it was in the early 1990s, while Antarctica is losing ice at about the same rate.” Altogether, ice melt since 1992 “has contributed to about 0.44 inches of sea level rise.” On Stoat, William M. Connolley says “Still – that adds up to 0.6 mm/yr. So it will have to grow if its to become interesting by 2100.” With ice-bound methane poised to mingle with carbon dioxide and accelerate global warming, interesting is a definite possibility. Scientists estimate that sea levels would rise by 200 feet if Antarctica thawed entirely. Not for several millennia, but an industrialist can dream.

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Time to Act on Climate Change

Although the science is getting cold, the conversation about climate change was warmed over by President Obama on Thursday. On Thoughts from Kansas, Josh Rosenau says “This is a welcome change from the complete silence of the last few years, but falls well short of what the American people and the world deserve.” Rosenau argues that with scientific consensus long established, an attempt at policy is overdue. California, the economic canary in a coal mine, just enacted a cap-and-trade system designed to curb carbon emissions. Meanwhile, climate change denialists strive to maintain a false equivalency. Taking issue with an article in New Scientist, Greg Laden writes “The idea that the effects of global warming are something of the future is a standard denialist lie.” In fact, Greg argues, global warming has been progressing incrementally since we first began “the wholesale burning of coal.” And on Stoat, William M. Connolley explains the buildup of ice in parts of Antarctica as a product of wind, not frigidity.

Runaway Warming

The extent of Arctic sea ice undulates like a yearly sine wave—rising in October, peaking in winter, and melting all spring and summer. This September we are likely to observe the lowest of lows; Greg Laden writes “There is less sea ice in the Arctic Circle than recorded in recent history.” More ice has also melted in Greenland this season, with 4 weeks still to go. Greg says, “glacial melting is both more important than one might think and also more complicated.” For example, the albedo of Greenland’s ice sheet (the proportion of sunlight reflected back into the atmosphere) varies depending on the snowpack. “The white fresh frozen snow that falls over the winter is highly reflective,” but “as it melts and gets slushy and mixes with water is has lower albedo.” This is an example of a feedback mechanism, as warmth and melting allows more sunlight into the ice. Additional feedback could occur as methane, a potent greenhouse gas, is freed from polar ice sheets.