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Black Carbon's Pandora Box

Collide-a-ScapeBy Keith KloorMay 4, 2009 9:29 PM


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The riddle of EPA's reluctance to consider soot a contributor to global warming has befuddled me since I read this story, which I thought made a solid case:

While carbon dioxide may be the No. 1 contributor to rising global temperatures, scientists say, black carbon has emerged as an important No. 2, with recent studies estimating that it is responsible for 18 percent of the planet's warming, compared with 40 percent for carbon dioxide.

Then my confusion deepened when this odd pairing of politicians called attention to black carbon's linkage to climate change. As Roger Pielke Jr., wonders:

So if the science is robust and the political will is there, why would EPA steer away from black carbon as an "easy win" on climate change?

Pielke guesses that EPA has "painted itself into a corner" with its recent global warming endangerment finding:

If black carbon is a pollutant due to its role in global and regional climate change, then as a precedent it opens up the door to a lot of uncomfortable questions and potential actions. For instance, if black carbon is an important forcing that affects the climate system with negative impacts, then why not water vapor emissions from land use, which also has been shown to influence local and regional climates? What about other land use change that alters surface energy budgets, such as albedo changes, irrigation, urbanization, and land clearing? And so on. Black carbon is an inconvenient forcing, and thus for EPA, rather than open up a can of worms, they have decided to follow the tried and true approach of hiding behind uncertainty.

Okay, can Roger Pielke Jr., or someone else then explain why James Inhofe has signed on to the congressional black carbon fact-finding mission? Following Pielke's logic, is he looking to call EPA's bluff, or is Inhofe motivated by true concern for the environment in this instance?

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