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Dear EarthTalk: How can it be that carbon dioxide emissions are the lowest they have been in the United States in 20 years despite the fact that we have no binding federal legislation limiting them? -- Jason Johnson, Port Chester, NY

Carbon dioxide emissions are indeed lower than at any time since 1994, according to data recently released by the U.S. Energy Information Administration (EIA). But if you think that the rise of the hybrid car, our embrace of public transit, walking, biking and those new windows on the house are behind the trend, think again. According to the EIA, increased energy efficiency has played a role, as have recent warmer winters and the recession, but the key driver has been the swapping out of coal at power plants and industrial facilities across the country for cleaner-burning and now more abundant natural gas.

The reason so much natural gas is around is the rise of hydraulic fracturing (“fracking”), a technique whereby drillers inject water and chemicals into underground shale rock deposits to free up otherwise trapped natural gas. Fracking has allowed U.S. oil companies to access huge natural gas deposits from the Marcellus Shale in the Northeast and elsewhere. The increased supply has brought natural gas prices down so that it has been cheaper than coal during the last few years. Our carbon footprint benefits because burning natural gas to generate electricity generates about half the carbon emissions of coal for every megawatt hour of power generated.

But Americans might not want to pat themselves on the back for too long, as the positive trend won’t continue indefinitely. “Replacing coal with natural gas reduces smokestack emissions of carbon dioxide, sulfur dioxide and mercury, but natural gas production and distribution comes with a host of problems, including methane leaks, contaminated water supplies, destroyed streams and devastated landscapes,” says Dan Lashof of the Natural Resources Defense Council (NRDC), a leading environmental group. “And while gas-fired power plants have lower carbon dioxide emissions than coal-fired ones, their emissions are still far too high to be considered a global warming solution.”

Furthermore, EIA says our energy-related carbon emissions are already rising again given recent increases in natural gas prices that have steered some utilities back to coal. The EIA anticipates U.S. energy-related carbon emissions rising 1.7 percent in 2013 and another 0.9 percent in 2014. The most important remaining question, says Lashof, is whether or not the U.S. will continue to reduce its CO2 emissions to achieve the president’s 2020 goal of a 17 percent reduction from 2005 levels—and eventually the 80 percent or more reductions needed to prevent the most dangerous risks of climate disruption. The target is within reach, he says, but power plant carbon pollution standards, among other changes, will be needed.

Lashof adds that the only way to keep the ball rolling is via a coordinated effort including stricter federal carbon and energy efficiency standards, new state renewable energy and energy efficiency incentives and reworked zoning and transportation policies that discourage the use of private automobiles. “We can build the clean energy future we need, but we aren’t there yet and it’s not going to happen by itself.”

Also, even if Americans can mobilize to get their emissions in check, will it matter? During 2012, energy-related carbon emissions fell by some 3.7 percent in the U.S., but rose 1.4 percent overall around the world. Indeed, global carbon emissions are on an unrelenting upward march as developing nations acquire the taste for the extravagant fossil-fuel-driven lifestyle perfected in the U.S.

EarthTalk® is written and edited by Roddy Scheer and Doug Moss and is a registered trademark of E - The Environmental Magazine (www.emagazine.com). Send questions to: earthtalk@emagazine.com. Subscribe: www.emagazine.com/subscribe. Free Trial Issue: www.emagazine.com/trial.


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