** A previous version of this post identified NASA as the authoring organization; it was actually NOAA. We regret the error.
Just one day after the U.S. Environmental Protection Agency announced it will regulate methane emissions from existing sources of oil and natural gas in order to “combat climate change,” scientists at the National Oceanic and Atmospheric Administration (NOAA) and National Institute of Water and Atmospheric Research in New Zealand (NIWAR) have released a new study finding that oil and natural gas producers are not to blame for a global increase in methane emissions. In fact, according to the researchers, the increased emissions are instead coming from wetlands and agriculture.
The lead author of the study, Hinrich Schaefer, an atmospheric scientist at the National Institute of Water and Atmospheric Research in Wellington, New Zealand, put it this way to Climatewire:
“Currently increasing methane levels are caused not by fossil fuel production but rather by wetlands or, more likely, agriculture.”
On the increase in agriculture, the study itself notes that India, China and South East Asia are likely emitting the highest amounts of methane: “India and China’s dominance in livestock-emissions and S.E. Asian rice cultivation are consistent with the location of the source increase.”
Climatewire further reported,
“Greenhouse gas inventories from U.S. EPA show that emissions from fossil fuel extraction have increased in recent years. But this has apparently not registered on the global scale. This is possibly because the U.S. energy industry contributes little to the overall burden of global fossil fuel emissions, Schaefer said.” (emphasis added)
The study concludes,
“The finding of a predominantly biogenic post-2006 in-crease is robust. Further, it seems likely that fossil-fuel emissions stagnated or diminished in the 1990s. Importantly, they are a minor contributor to the renewed [CH4]-rise. This contradicts emission inventories reporting increases of all source types between 2005 and 2010 with a major (~60%) thermogenic contribution (21, 22). The predicted δ13C(So) ~ –48‰ (or more 13C-enriched) produces a slight δ13C(Atm)-increase that cannot be reconciled with the measured marked decline (Fig. 4B). The finding is unexpected, given the recent boom in unconventional gas production and reported resurgence in coal mining and the Asian economy (21, 22). Our isotope-based analysis suggests that the [CH4]-plateau marks not a temporary suppression of a particular source but a reconfiguration of the CH4-budget. Either food production or climate-sensitive natural emissions are the most probable causes of the current [CH4]-increase. These scenarios may require different mitigation measures in the future.” (emphasis added, p. 3)
To conduct the study, the researchers used a fingerprinting technique that evaluates thermogenic methane associated with oil and natural gas development, as well as biogenic methane associated with natural or agricultural causes. The researchers found that thermogenic methane did not increase, even during the oil and natural gas boom. As the study states,
“We reconstruct the global history of [CH4] and its stable carbon isotopes from ice cores, archived air and a global network of monitoring stations. A box-model analysis suggests that diminishing thermogenic emissions, probably from the fossil-fuel industry, and/or variations in the hydroxyl CH4-sink caused the [CH4]-plateau. Thermogenic emissions didn’t resume to cause the renewed [CH4]-rise after 2006, which contradicts emission inventories. Post-2006 source increases are predominantly biogenic, outside the Arctic, and arguably more consistent with agriculture than wetlands. If so, mitigating CH4-emissions must be balanced with the need for food production.” (emphasis added)
This new NOAA/NIWAR study further bolsters research by Energy In Depth, which shows that EPA’s costly methane rule would account for a reduction of a mere 0.004 degrees Celsius – or four one-thousandths of one degree – by the year 2100. In other words, it would have virtually no impact on the climate.
It’s also right line with an analysis from National Economic Research Associates (NERA), which concluded that EPA’s projected benefits from its methane rules are “highly uncertain and very likely overstated,” and the agency’s figures “lack the appropriate peer review that is necessary for use in supporting regulatory policy.”
EPA Administrator Gina McCarthy said recently that EPA is still just learning about the oil and natural gas industry. Looks like the agency still has quite a lot to learn.