Leaky pipes, leaky cows
With so much focus on the carbon dioxide released by burning coal and oil, there’s been too little public attention to how methane, the main component of natural gas, adds to climate change. As a new plan by the Obama administration recognizes, the nation needs a strategy to handle emissions from a variety of sources — one that maximizes the percentage of methane put to useful purposes and minimizes what ends up in the atmosphere.
Unfortunately, residents of big cities like Boston receive natural gas via old pipe systems with thousands of leaks that allow methane to escape into the atmosphere. Other major sources of methane are agriculture and landfills, which together account for 54 percent of emissions. New methane-control technology and decreases in paper waste and meat consumption have resulted in a decrease in methane emissions since 1990. But levels could increase again as natural gas usage increases. A study published in February in the journal Science found that methane leaks from US gas systems are 50 percent higher than previous federal estimates. “And that’s a moderate estimate,” said lead author Adam Brandt of Stanford University.
In response, the White House vows to update standards for landfills and the flaring and venting of gas in oil and gas production on federal lands. It will push for voluntary capture programs in coal mines and voluntary biogas programs on dairy farms to turn the methane in manure into electricity.
The administration also says it will consider new regulations by 2016 if its ongoing review of methane warrants them. Significantly, the Stanford study warned that scientists have a “poor understanding” of the sources of excess methane, and some steps that seem useful, such as when cities with leaky pipes switch from diesel buses to natural gas vehicles, may be counterproductive. What’s crucial is to identify substantive measures — and ignore those that are cosmetic at best.