Sunday, April 14, 2013

The Seinfeld Dilemma: Should China Frack to Contain Climate Change?

In the New York Times, Elizabeth Mueller of BEST calls on China to exploit its shale gas by fracking it out:
Instead of fighting hydraulic fracturing, environmental activists should recognize that the technique is vital to the broader effort to contain climate change and should be pushing for stronger standards and controls over the process.

Nowhere is this challenge and opportunity more pressing than in China. Exploiting its vast resources of shale gas is the only short-term way for China, the world’s second-largest economy, to avoid huge increases in greenhouse gas emissions from burning coal.
Except...fracking natural gas actually increases greenhouse gas emissions, emitting more methane through leakage while decreasing carbon dioxide from burning the fuel. That was the conclusion of a 2011 study by Howarth et al:
...Natural gas is composed largely of methane, and 3.6% to 7.9% of the methane from shale-gas production escapes to the atmosphere in venting and leaks over the lifetime of a well. These methane emissions are at least 30% more than and perhaps more than twice as great as those from conventional gas. The higher emissions from shale gas occur at the time wells are hydraulically fractured—as methane escapes from flow-back return fluids—and during drill out following the fracturing. Methane is a powerful greenhouse gas, with a global warming potential that is far greater than that of carbon dioxide, particularly over the time horizon of the first few decades following emission. Methane contributes substantially to the greenhouse gas footprint of shale gas on shorter time scales, dominating it on a 20-year time horizon. The footprint for shale gas is greater than that for conventional gas or oil when viewed on any time horizon, but particularly so over 20 years. Compared to coal, the footprint of shale gas is at least 20% greater and perhaps more than twice as great on the 20-year horizon and is comparable when compared over 100 years.
Perhaps not coincidentally, atmospheric methane levels measured at Mauna Loa started to rise again just about the time the U.S. started its current round of fracking:

The leveling off in the first half of last decade may have been due to changes in Russian production of natural gas due to the collapse of the Soviet Union. Here's a paper in ACPD that discusses the increase more thoroughly, which speculates that part of the recent increase was due to natural wetland emissions. Russian natural gas production hasn't increased overall in almost a decade, while US emissions have:

graph of Annual dry natural gas production: U.S. and Russia, 1996-2010, as described in the article text

So should China (or the US, for that matter) frack to contain climate change? It would mean less CO2 emissions, which can be in the atmosphere and oceans for centuries (if not longer -- much longer), while increasing a shorter-lived but more potent greenhouse gas, methane. It's kind of like that Seinfeld skit where he's in a drug store trying to decide between two bottles of cold medicine:
"This is quick-acting, but this is long-lasting. When do I need to feel better, now or later?"
Of course, the reality is that China (and the US) will frack if it's cheaper and provides the energy needed, with little real concern for climate change.

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