In class and in comments, some of you have raised the question of whether the process of climate change is so far along that our attempts at mitigation are pointless. In particular, someone pointed out that it can take a century or more to capture or reduce the CO2 that has already been released into the atmosphere and tens of thousands of years for it to be permanently removed through geological processes.
Since that’s the case, how much of an impact will a slow implementation of alternatives to fossil fuels have?
I mentioned this article in the New York Times, which argues that one possibility is to focus on a major source of methane in the atmosphere. Methane is produced at lower levels than CO2, but it has strong effects. It says:
Unlike carbon dioxide, which can remain in the atmosphere a century or more once released, methane persists in the air for about 10 years. So aggressively reining in emissions now would mean that far less of the gas would be warming the earth in a decade or so.
Methane is also a valuable target because while it is far rarer and more fleeting than carbon dioxide, ton for ton, it traps 25 times as much heat, researchers say.
Yet while federal and international programs have encouraged companies to seek and curb methane emissions from gas and oil wells, pipelines and tanks, aggressive efforts are still far from the industry norm.
As a result, some three trillion cubic feet of methane leak into the air every year, with Russia and the United States the leading sources. (This amount has the warming power of emissions from over half the coal plants in the United States.) And government scientists and industry officials caution that the real figure is almost certainly higher.
Another contributor to global warming is black soot, and it has an even lower residence time than methane. Here’s another NYTimes article:
“In terms of climate change we’re driving fast toward a cliff, and this could buy us time,” said Dr. Ramanathan.
[D]ecreasing soot could have a rapid effect. Unlike carbon dioxide, which lingers in the atmosphere for years, soot stays there for a few weeks. Converting to low-soot cookstoves would remove the warming effects of black carbon quickly, while shutting a coal plant takes years to substantially reduce global CO2 concentrations.
But the awareness of black carbon’s role in climate change has come so recently that it was not even mentioned as a warming agent in the 2007 summary report by the Intergovernmental Panel on Climate Change that pronounced the evidence for global warming to be “unequivocal.” Mark Z. Jacobson, professor of environmental engineering at Stanford, said that the fact that black carbon was not included in international climate efforts was “bizarre,” but “partly reflects how new the idea is.” The United Nations is trying to figure out how to include black carbon in climate change programs, as is the federal government.
In last week’s Science magazine (the journal of the AAAS), an article evaluating climate change policy supports pursuing short-term and long-term climate mitigation efforts at the same time (and through two separate treaties).
Stacy C. Jackson writes
Thus, short- and medium-lived sources (black carbon, tropospheric ozone, and methane) must be regulated separately and dynamically. The long-term mitigation treaty should focus exclusively on steady reduction of long-lived pollutants. A separate treaty for short- and medium-lived sources should include standards that evolve based on periodic recommendations of an independent international scientific panel. The framework of “best available control technology” (strict) and “lowest achievable emissions rate” (stricter) from the U.S. Clean Air Act can be used as a model.
“Parallel Pursuit of Near-Term and Long-Term Climate Mitigation” Science 326 (Oct. 23 2009): 526-527.
I’ll post the article on MyCourses for anyone who’s interested in using it.
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