Bob CollinsIn our rush to save the planet by switching to non-oil sources of fuel, we might be making some things worse, at least where natural gas is concerned.
A lot of transit systems, for example, have converted buses to natural gas from diesel. And it’s true that burning natural gas is cleaner than diesel. But a report out today says the process of producing the natural gas offsets many of the gains, the New York Times is reporting.
“Switching from diesel to natural gas, that’s not a good policy from a climate perspective” the study’s lead author, Adam R. Brandt, an assistant professor in the Department of Energy Resources at Stanford, said.
The report adds weight to efforts by New York and other Northeastern states to push the federal government to regulate methane emissions. Currently, there are no federal regulations on methane emissions from oil and gas production, although some states are considering implementing such rules.
The finding on trucks and buses is a blow to years of public policy efforts to switch the vehicles from diesel to natural gas, an effort aimed at decreasing pollution as well as America’s dependence on foreign oil.
The study notes, however, that switching from coal-fired to natural gas-fired electricity plants is a net benefit.
Why is methane increasing after leveling off? Ars Technica says there’s no conclusive research — yet — to blame fracking and shale mining.
The gas is produced by many sources—some human-caused, some not. Microbes are the biggest source. Archaea can make their homes in low-oxygen environments like wetlands, but they are also responsible for the methane generated in the digestive systems of cud-chewing animals like cows, as well as termites.
Incomplete combustion of organic matter during wildfires and biofuel use are also sources. And, of course, natural gas that escapes into the atmosphere from underground reservoirs of hydrocarbons is another.
The researchers’ best estimate of the amount of methane coming from natural gas in the US is much smaller than the leakage rates that some fracking opponents suggest. The uncertainty in these estimates is big enough that higher leakage rates cannot be ruled out, though.
Even if we kept using natural gas (and releasing methane) for 100 years, Ars Technica says, leaking methane “still means a smaller greenhouse footprint at the end of that time than coal would have generated.”
But another researcher, Cornell University civil and environmental engineering professor Anthony Ingraffea, disagrees with the study’s conclusion that overall natural gas is more beneficial for the climate than coal over the span of a century.
Ingraffea, who conducted a similar study in 2011, told Climate Central that researchers shouldn’t be issuing reports on the environmental impacts over 100 years because we don’t have 100 years.
“… We only have about 20-30 years before we reach the warning zone of temperature rise that could lead to climate tipping points,” he said.
