Climate change estimates on the low side

Skeptics and optimists could both be wrong:

In fact, as Dr. Alley reminds anyone who will listen, and as he recently told a Congressional committee, the estimate of 5 or 6 degrees is actually mildly optimistic. Computer programs used to forecast future climate show it as the most likely outcome from a doubling of carbon dioxide, but those programs also show substantial probabilities that the warming will be much greater.

The true worst case from doubled carbon dioxide is closer to 18 or 20 degrees of warming, Dr. Alley said — an addition of heat so radical that it would render the planet unrecognizable to its present-day inhabitants.

Well over half the species on our planet would be exctinct by that time, so they won't be around to "recognize" anything.

Dr. Alley calls the usual news media presentation of the issue a form of “false balance.” In his view, mainstream climate science should be seen as coming down on the conservative side of a range of numbers that runs from 2 degrees to 20 degrees. And in setting public policy, he said, lawmakers need to entertain the possibility that any of these numbers is correct.

In climate science, the problem of how the earth will react to extra greenhouse gases is known as “climate sensitivity,” and it is classically formulated as the average temperature increase that can be expected to occur if carbon dioxide doubles from its preindustrial value of 280 parts per million. By itself, this is a hard problem, one that consumes the lives of thousands of scientists. But projecting the actual future temperature of the earth involves even greater complexities.

And the differences in their findings gives the head-in-the-sand skeptics even more fodder for their foolishness. But it appears the President and the EPA understand the danger and are intent on taking steps, regardless of what the industry-tainted Congress thinks:

EPA officials said they would set new performance standards requiring stricter pollution technology for electric utilities and oil refineries, which together account for almost 40 percent of U.S. greenhouse gas emissions.

"We are following through on our commitment to proceed in a measured and careful way to reduce [greenhouse gas] pollution that threatens the health and welfare of Americans, and contributes to climate change," EPA Administrator Lisa P. Jackson said in a statement.