Global Science Report is a weekly feature from the Center for the Study of Science, where we highlight one or two important new items in the scientific literature or the popular media. For broader and more technical perspectives, consult our monthly “Current Wisdom.”
First China. Now the U.S.
It was big news last November when it was revealed that China had been under-reporting its coal consumption by nearly 20 percent. The big implication was that China’s greenhouse gas emissions were also much larger than being reported, complicating the (then) upcoming U.N. climate negotiations in Paris.
Now comes evidence that the U.S. has been underreporting its methane emissions—a potent greenhouse gas—by some 50 percent or more. And what’s worse, is that over the past decade or so, instead of methane emissions having declined by about 10 percent as reported by the EPA, they have in fact grown by more than a whopping 30 percent. Not only would this information also have (had it been available) complicated the U.N. Paris talks, but it would have taken a lot of the shine off the U.S. emissions reduction efforts that President Obama was touting at the conference last December.
The new evidence is presented in a just-published paper in the scientific journal Geophysical Research Letters by a team led by Harvard PhD candidate Alexander Turner. Turner and colleagues examined several measures of methane emissions occurring in the U.S. (including in situ measurements and remote satellite observations) and concluded that EPA estimates were way off. They wrote:
National inventory estimates from the US Environmental Protection Agency (EPA) indicate no significant trend in US anthropogenic methane emissions from 2002 to present. Here we use satellite retrievals and surface observations of atmospheric methane to suggest that US methane emissions have increased by more than 30% over the 2002-2014 period… This large increase in US methane emissions could account for 30-60% of the global growth of atmospheric methane seen in the past decade.
The implications are huge—at least when it comes to our advertised role as a supposed leader in climate change mitigation efforts.