NOAA: Methane Emissions ‘Being Driven by Natural and Agricultural Emissions, Not Fossil Fuels’

Last year, EID highlighted the fact that several recent peer-reviewed studies have concluded microbial sources of methane such as wetlands, agriculture and rice paddies are responsible for the increase in global emissions since 2007 — not oil and natural gas production.

And now, recent updates to the National Oceanic and Atmospheric Administration’s (NOAA) website further debunks environmentalists’ misguided claim that shale development is responsible for driving up global methane emissions. From,

“NOAA observations, analysis, and field research campaigns suggest the increase (in global methane emissions) is being driven by natural and agricultural emissions, not fossil fuels.”

This conclusion is based on the fact that NOAA research found the amount of methane carrying a rare isotope associated with oil and natural gas production —carbon-13 — has dropped “significantly” since 2007. As NOAA researchers Rebecca Lindsey and Michon Scott write,

“That drop casts doubt on one of the first explanations experts considered for the post-2007 rise: an increase in methane emitted from fossil fuels, including ‘fugitive’ methane gas escaping during oil and natural gas drilling. Instead, the chemical fingerprints point toward agricultural and wetland emissions from the tropics.”

As the following NOAA graphic illustrates, the amount of carbon-13 detected (lighter colored lines) started to fall in 2007 while overall methane levels (darker colored lines) increased in each of the four latitude zones NOAA collected air samples from.

As Lindsey and Scott write, the data simply don’t support the anti-fracking narrative that shale development has driven up global methane emissions, despite the fact that global emissions started to rise about the time the shale revolution started,

“The post-2007 uptick in global methane levels roughly coincides with the rapid deployment of natural gas ‘fracking’ in the United States, making fugitive emissions a logical suspect. But attempts to verify the connection have produced counter-intuitive results, according to Stefan Schwietzke, a methane expert from the Cooperative Institute for Research in Environmental Sciences (a NOAA-University of Colorado Boulder partnership).

“Schwietzke’s research suggests that methane emissions from fossil fuels are higher than countries’ self-reported inventories suggest, and they may even be increasing. And yet, he explained via email, methane derived from fossil fuels is enriched with carbon-13 — a rare, heavy isotope of carbon — and air samples show that the amount of carbon-13-flavored methane is dropping worldwide.

“The drop seems to rule out fossil fuel emissions, wildfires, or biomass cook stoves as the reason for the post-2007 methane surge. All those sources of methane, to a greater or lesser extent, are enriched in carbon-13, not depleted.”

Furthermore, as the above NOAA graphic illustrates, “Declines in the late 1990s through the mid-2000s are concentrated in the Northern Hemisphere. The leading hypothesis is that industrialized countries, including the United States, got better control of ‘fugitive’ methane emissions, which escape during drilling and pumping of oil and natural gas.”

This conclusion is supported by the latest U.S. EPA Greenhouse Gas Inventory, which shows methane emissions from oil and natural gas systems have decreased 19 percent since 1990 (249 million metric tons to 202 mmt) at the same time natural gas production has increased 52 percent and oil production has increased 28 percent.

Several recent studies (see below) also support the data presented in the following NOAA graphic showing agriculture and wetlands are a larger source of global methane than fossil fuel production and use.

  • National Oceanic and Atmospheric Administration (NOAA) Study: This study found that microbial sources such as rice paddies and wetlands are the cause of the global increase in methane emissions. Lead author Stefan Schwietzke of NOAA at the University of Colorado Boulder also emphasized that fossil fuel development is “not responsible for the increase in total methane emissions observed since 2007.”
  • Department of Earth Sciences at Royal Holloway, University of London Study: This study found the spike in global methane emissions since 2007 has been “largely driven” by tropical wetlands and agriculture. Using measurements made by NOAA’s Cooperative Global Air Sampling Network in three locations (the Canadian Artic, the south Atlantic and South Africa), a combination of latitudinal analysis and isotopic data led researchers to determine a majority of the methane increase since 2007 has a biogenic signature, meaning it cannot be attributed to thermogenic methane from oil and gas development. The study further notes that the tropical wetlands are responsible for as much as a quarter of global methane emissions, and that significant weather events — such as La Nina in 2007 and 2008 — could explain a nearly 50 percent hike in methane emissions when compared to the last half decade.
  • NOAA and the National Institute of Water and Atmospheric Research in New Zealand (NIWAR) Study: This study also found increased global methane emissions are coming from wetlands and 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.”

Furthermore, NOAA’s statement that “carbon dioxide is the 800-pound gorilla” when it comes to global warming because “it’s the most abundant of the long-lived greenhouse gases that human activities generate” is also worth emphasizing, considering the Energy Information Administration (EIA) credits 62 percent of the total 12 percent of U.S. CO2 reductions from 2005 levels to increased natural gas use.

All these facts considered, the science is clear: methane emissions from oil and natural gas development are not driving the global increase in emissions observed since 2007, and are actually declining as production remains near record levels. Furthermore, increased natural gas use is responsible for a vast majority of U.S reductions of carbon dioxide — the greenhouse gas NOAA considers the “800-pound gorilla” in the fight to combat climate change.

So why do environmentalists continue to make methane emissions from oil and natural gas systems — specifically costly regulations that would reduce global temperatures a mere 0.0047 degrees Celsius by the year 2100 — a focal point of the climate change debate?

It is becoming more and more evident that this campaign is driven more by politics and ideology than science.


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