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While global methane emissions are up, study says fossil fuels not the culprit

NOAA researcher Stefan Schwietzke and pilot Stephen Conley prepare to take off on a research flight to measure methane emissions in Colorado.

Will Von Dauster / courtesy of NOAA

NOAA researcher Stefan Schwietzke and pilot Stephen Conley prepare to take off on a research flight to measure methane emissions in Colorado.

A new study from NOAA, the National Oceanic Atmospheric Administration, puts a new twist on a tricky question about the impact of increased oil and gas production on greenhouse gas emissions. Scientists have detected increased rates of methane emissions globally since 2007. That uptick corresponds to the rapid boom in U.S. shale gas and shale oil production, and some hypothesized that the two could be connected. But it turns out that the correlation may not necessarily be a cause.

The research published Wednesday in the journal Nature found that although previous methane emissions from fossil fuel production, which includes coal, oil and gas, were significantly underestimated, the overall atmospheric increases in methane is not due to oil and gas production. NOAA, which has been measuring methane in the atmosphere since 1984, says the global increase in methane could be coming from microbial sources including wetlands, rice paddies and agricultural livestock like cows. Methane is considered more potent a greenhouse gas than carbon dioxide because although it breaks down more quickly than CO2,  it traps heat 28 times more effectively over the course of 100 years.

Researchers compiled the largest database yet on global methane, which produced a truer picture of the total number of methane molecules in the atmosphere, as well as a clearer view of where that methane originated. As a result, the researchers say they’ve identified more methane from oil and gas production than previously thought, an increase of 20 to 60 percent. But that’s not enough to account for the global rise of methane in the atmosphere.

“We recognize the findings might seem counterintuitive – methane emissions from fossil fuel development have been dramatically underestimated – but they’re not directly responsible for the increase in total methane emissions observed since 2007,” said lead author Stefan Schwietzke, a scientist with the Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado Boulder, working in NOAA’s Earth System Research Laboratory.

Schwietzke says that while natural gas production has increased, the rate of methane leakage, or the amount of natural gas that escapes or is vented as measured against the amount that is captured and sent through a pipeline to market, has actually decreased from 8 percent to 2 percent in the last 30 years.

“What we found is that the absolute amount of emissions has remained constant, while production of fossil fuels has increased dramatically,” said Schweitzke.

The two percent leakage rate holds up to research conducted by Carnegie Mellon University, which measured methane leaks from both conventional and unconventional wells in Pennsylvania’s Marcellus Shale. Their results were published this year in Environmental Science and Technology.

“The two percent is in the same ballpark as what we’ve been measuring,” said Albert Presto, a professor at Carnegie Mellon University who was not involved in the NOAA research, but was the the lead investigator on the Carnegie Mellon study. Presto’s work, like the NOAA report, also found that leaks from gas sites were higher than previous measurements, in this case those recorded by state regulators.

But that two percent is significant when comparing the greenhouse gas footprint of natural gas with coal.

A breakdown of sources of methane in the atmosphere.

NOAA

A breakdown of sources of methane in the atmosphere.

In 2011, Cornell University professors Robert Howarth and Anthony Ingraffea, published a controversial paper on shale gas, raising questions about the amount of methane released during production and whether those emissions cancelled out the gains from less carbon dioxide emitted at the power plant, when compared to coal. Citing a lack of data and the need for more research, Howarth and Ingraffea estimated that methane emissions from shale gas was 3.6 to 7.9 percent of total production. More research and more debates over the climate trade-off between coal and natural gas have followed. The Environmental Defense Foundation has conducted it’s own studies, working with industry to encourage plugging leaks and eliminate flaring.

In a study published in the Proceedings of the National Academy of Sciences in 2012, EDF scientists Ramon Alvarez and Steve Hamburg estimated that replacing coal burning power plants with natural gas benefits the climate as long as the methane emissions rates of gas production stay below 3.2 percent.

“This [NOAA study] sort of suggests that they’re either at that limit or below it,” said Presto.

NOAA’s Stefan Schwietzke says different researchers have concluded that different leak rates mark a threshold when attempting to determine the point at which burning natural gas emits less greenhouse gas than coal. But he says, his results are “within the range” of what most researchers conclude burning natural gas is less damaging than coal.

Still, the NOAA researchers say the industry can and should do more to reduce methane emissions.

“Our study shows that leaks from oil and gas activities around the world are responsible for a lot more methane than we thought,” said co-author Lori Bruhwiler, a NOAA research scientist. “The good news is that fixing leaking oil and gas infrastructure is a very effective short-term way to reduce emissions of this important greenhouse gas.”

Some scientists and activists say regardless of the leakage rates, climate warming is happening at such a rapid rate that as much as possible fossil fuels need to remain in the ground while the world switches to renewable energy sources.

Although scientists have always known that microbial sources of methane represented a large portion in the atmosphere, the research could have an impact when it comes to tackling sources of greenhouse gases that are not related to fossil fuel production. Schwietzke says recent rise in atmospheric methane is from microbial sources. He says more work needs to be done to pinpoint what microbial source is the greatest culprit. Another NOAA research paper released this year points to equatorial wetlands, which have seen an increase in precipitation since 2007 due to weather patterns like La Nina. Other microbial sources of methane include ruminant emissions (cow burps for example), rice paddies and landfills. Biomass sources of methane include forest fires, and wood burning cook stoves, primarily used in developing countries.

Comments

  • bumpski

    My trees are dying.

    “replacing coal burning power plants with natural gas benefits the climate as long as the methane emissions rates of gas production stay below 3.2 percent.”

    This a good article and a good point by those interviewed. But so many articles about this topic, coal versus gas, ignore all the other negatives of coal, as an energy source.

    1. Acid rain over the entire Northeast.
    a. my trees fall and have no roots
    b. acid rain depletes nutrients, magnesium is depleted.
    2. Mercury pollution, and mercury laden freshwater fish.
    3. Abandoned and burning coal mine methane (and other) emissions are not quantified.
    a. one active coal mine releases as much methane as a typical natural gas well would if opened to the atmosphere.
    b. The are 600 active coal mines in the US alone, the are 500,000 abandoned coal mines (miners could be sealing these off for decades)
    c. There are hundreds of coal mine fires releasing untold quantities of various gases.
    4. Fly ash ponds pollution.
    a. acidifying and poisoning creeks and rivers.

    When all factors of damage are considered, we should be running to natural gas, for heat and power. The Northeast will not be able to heat its homes with solar, or wind power, in the near future. Large solar farms, attempting to address this problem, are clear cutting trees in many areas. Trees turn CO2 into Oxygen and they are dying all over the place due to acid rain.
    Amazingly, even with the bonanza in the Pennsylvania marcellus, the entire Northeast (EXCEPT New York state) is forced to import natural gas in the winter, and gee, New York state is getting the cheapest natural gas prices in the nation, and uses an amazing amount!

    See comments in the link below for more details.
    https://stateimpact.npr.org/pennsylvania/2015/03/18/measuring-the-climate-trade-off-between-coal-and-natural-gas/

    • JMan

      Acid rain over the entire Northeast.

      Not an issue for most modern plants since they’ve almost all been fitted with scrubbers since the 80′s.

      2. Mercury pollution, and mercury laden freshwater fish.

      Again, not an issue, 99.9% of the mercury is trapped in the scrubber or the bag house filters.

      3. Abandoned and burning coal mine methane (and other) emissions are not quantified.

      —a. one active coal mine releases as much methane as a typical natural gas well would if opened to the atmosphere.

      Please cite a source for this statistics, I’m on the technical side of the industry and I’ve never heard this. Cite your source when you throw out such specific generalist statements.

      —b. The are 600 active coal mines in the US alone, the are 500,000 abandoned coal mines (miners could be sealing these off for decades)

      Sealing off a mine doesn’t trap the methane, if there’s enough gaseous methane, it will accumulate and it will find its way to the surface through cracks in the rocks over decades. If the rock is non-porous, and there’s enough methane to create enough pressure, the chances of that area being a coal mine to begin with is low because it would be impossible to manage the methane generation in the coal bed while the mine is active.

      —c. There are hundreds of coal mine fires releasing untold quantities of various gases.

      Again, I work in the industry, and I would ask you to cite your source. Hundreds of fires??? Please provide the source of your information, and qualify the term “fires”. A belt roller friction fire in the woods between the mine and the load out does not qualify as a “release of various gases”. The type of fire you are “Implying” is what’s called a face fire or a coal stack fire at the loadout where actual coal is burning in large quantity. I would challenge you to provide further information on the location and frequency of those face fires &/or stock fires, since both are very serious occurrences. They should be well documented.

      4. Fly ash ponds pollution.

      Majority of fly ash is captured in the bag house filter in the emission systems of power generators. This fly ash is often disposed of in a slurry solution that gets pumped to a retention pond that over time is allowed to evaporate off the water and the fly ash eventually gets buried beneath the earth. Not sure how that’s considered pollution since it’s being placed right back where it came from.

      —a. acidifying and poisoning creeks and rivers.

      The only poisoning of creeks and rivers that I’m aware of in recent history was done by the US EPA. While this issue was a legitimate issue over the past 30 years, understanding and mitigating it has become a requirement in the industry & is no longer an environmental issue. The only sources of acid mine drainage today are old abandon mines from the early 20th century and mines abandoned in the 70′s and 80′s that were not constructed or shut down responsibly. For modern working mines, this is a non-issue due to decades of science and engineering that’s gone into mitigation plans that are put in place every time a new mine is opened up today.

      • bumpski

        Sir

        https://stateimpact.npr.org/pennsylvania/2015/03/18/measuring-the-climate-trade-off-between-coal-and-natural-gas/

        At the link above which was also at the end of my post there are 4 comments by bumpski at the end of the article which provide quite a few specific sources for what was said in my post above. So I see you must have missed the one reference above I did provide, or not have taken the time to check it out..

        So now I ask you for your sources? You provided none!

        References to what I have said are simple searches away. You’ve heard of Centralia right. There’s a fire cooking away in Wilkes Barre, there are many others. Natural gas fired generation is now available burning pure oxygen, and these power stations are capable of being air cooled they are so efficient. Conceivably a power station such as this could be located near a coal mine fire and the CO2 waste used to slowly extinguish the fire.

        Sure there are scrubbers but we burn a lot of coal and in protected lands the rules aren’t as tough. 0.1% of a lot, can still be a lot! Then there’s radon too!

        My grandfather and uncle were coal MINERS, an honorable profession, but we have an opportunity to significantly improve the environment at lower cost.

        I’m surprised you didn’t mention the methane capture systems that are technically available for coal mines, but not in use.

    • NorthernTier

      Also, the “beneficial use” of bottom ash as anti-skid in the winter. (Which, in fact, builds up in intersections/on turns and causes accidents.)

    • http://flippetyfloppety.blogspot.com Karen Orlando

      Hard to believe we are having this coal vs natural gas discussion in the present at all isn’t it? Seems kind of backwards to me.

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