During a speech today, President Bush said “First of all, the globe is warming. The fundamental debate — is it manmade or natural?” Actually, that’s no longer a debate, at least among the overwhelming majority of scientists. The Guardian reports:
Natural variation in the Earth’s climate, or changes in solar activity or volcanic eruptions, which have been suggested as alternative explanations for rising temperatures, could not explain the data collected in the real world. Models based on man-made emissions of greenhouse gases matched the observations almost precisely.
“What absolutely nailed it was the greenhouse model,” Dr [Tim] Barnett [of the Scripps Institution of Oceanography in La Jolla, California] told the American Association for the Advancement of Science conference in Washington. “Two models, one designed in Britain and one here in the US, got it almost exactly. We were stunned.”
…Only the greenhouse models replicated the changes that have been observed in practice. “All the potential culprits have been ruled out except one,” Dr Barnett said.
It is also the position, curiously enough, of the Bush administration’s EPA since 2002. From the Christian Science Monitor:
In a report to the United Nations, the Environmental Protection Agency says that man-made greenhouse gases in the US will increase 43 percent between 2000 and 2020. And while acknowledging some scientific uncertainties, the EPA says that the recent warming trend “is real and has been particularly strong within the past 20 years … due mostly to human activities.”
How much longer will Bush keep his head in the sand?