Scientists may have figured out why a potent greenhouse gas is rising. The answer is scary.

[Zorro]

Almost two decades ago, the atmosphere’s levels of methane — a dangerous greenhouse gas that is over 80 times more potent than carbon dioxide in the short term — started to climb. And climb.

Methane concentrations, which had been stable for years, soared by 5 or 6 parts per billion every year from 2007 onward. Then, in 2020, the growth rate nearly doubled.

Scientists were baffled — and concerned. Methane is the big question mark hanging over the world’s climate estimates; although it breaks down in the atmosphere much faster than carbon dioxide, it is so powerful that higher than expected methane levels could shift the world toward much higher temperatures.

But now, a study sheds light on what’s driving record methane emissions. The culprits, scientists believe, are microbes — the tiny organisms that live in cows’ stomachs, agricultural fields and wetlands. And that could mean a dangerous feedback loop — in which these emissions cause warming that releases even more greenhouse gases — is already underway.

https://www.washingtonpost.com/climate-environment/2024/11/04/methane-emissions-microbes-climate-change/

[Think. Again.]

1. K&R

[LastDemocratInSC]

2. Research at UC Davis shows a possible solution.

3 paragraphs from the article:

A bit of seaweed in cattle feed could reduce methane emissions from beef cattle as much as 82 percent, according to new findings from researchers at the University of California, Davis. The results, published today (March 17) in the journal PLOS ONE, could pave the way for the sustainable production of livestock throughout the world.

“We now have sound evidence that seaweed in cattle diet is effective at reducing greenhouse gases and that the efficacy does not diminish over time,” said Ermias Kebreab, professor and Sesnon Endowed Chair of the Department of Animal Science and director of the World Food Center. Kebreab conducted the study along with his Ph.D. graduate student Breanna Roque.

“This could help farmers sustainably produce the beef and dairy products we need to feed the world,” Roque added.

https://caes.ucdavis.edu/news/feeding-cattle-seaweed-reduces-their-greenhouse-gas-emissions-82-percent

[Tree Lady]

8. This is why I love science

they come up with the answers.

[Coexist]

10. elegant solution!

[sl8]

11. The warming wetlands seem like a tougher nut to crack.

Last edited Tue Nov 5, 2024, 08:18 PM - Edit history (1)

As the study authors point out, you can turn off the natural gas tap very easily (given the will to do so), but you can't turn off the tap on warming wetlands.

[orthoclad]

3. Nothing new. Is WaPo greenwashing fracking?

Methanogenic bacteria and ways to reduce methane from beef have been studied for years.

"Almost two decades ago, the atmosphere’s levels of methane — a dangerous greenhouse gas that is over 80 times more potent than carbon dioxide in the short term — started to climb. And climb."

Gee, just when we started fracking fossil gas in large amounts. I've seen the recent satellite pics of huge methane plumes emitted from wells, pipelines, pumping stations. The explosion in fossil gas drilling also enables plastic pollution, because fossil gas is the feedstock for for plastic production. Cheap abundant source, cheap abundant plastic - now every human being alive has microplastic in their bloodstream.

Bacteria produce methane, increased temperatures increase bacterial activity, but by all means, let's blame cow belches and wetlands and ignore that gas well behind the curtain.

[harumph]

4. Spot on.

[orthoclad]

5. WaPo's been going ruling class for some time

I feel bad for the conscientious people on the staff who are suffering.

[misanthrope]

6. Thawing permafrost isn't to be ignored either

Methane has been trapped in the subarctic zones for numerous ages and is now escaping. As natural disasters wreak havoc and kill flora and fauna, their decomposition adds to the methane levels, too.

[NickB79]

7. It's abundantly clear that net zero emissions goals are a joke

Between the Amazon burning up, the boreal forests burning up, the permafrost thawing, and microbes emitting methane, the climate will keep warming for centuries even if we stopped emitting carbon entirely tomorrow. We're pretty much locked into 3-4C of warming at this point, because all the models that project us staying under 2C assume those natural carbon sinks won't turn into carbon emitters. They're wrong.

[sl8]

9. Paper:

The special characters and superscript/subscript don't copy & paste well; it's better viewed at the source. Basically, they determined the sources of the increased methane by analyzing the carbon isotopes in the methane.

https://www.pnas.org/doi/10.1073/pnas.2411212121

Rapid shift in methane carbon isotopes suggests microbial emissions drove record high atmospheric methane growth in 2020–2022

Sylvia Englund Michel, Xin Lan, John Miller, +7, and Jianghanyang Li
Edited by Mark Thiemens, University of California San Diego, La Jolla, CA; received June 19, 2024; accepted September 5, 2024

October 21, 2024

Vol. 121 | No. 44
Abstract

The growth rate of the atmospheric abundance of methane (CH4) reached a record high of 15.4 ppb yr?1 between 2020 and 2022, but the mechanisms driving the accelerated CH4 growth have so far been unclear. In this work, we use measurements of the 13C:12C ratio of CH4 (expressed as ?13CCH4) from NOAA’s Global Greenhouse Gas Reference Network and a box model to investigate potential drivers for the rapid CH4 growth. These measurements show that the record-high CH4 growth in 2020–2022 was accompanied by a sharp decline in ?13CCH4, indicating that the increase in CH4 abundance was mainly driven by increased emissions from microbial sources such as wetlands, waste, and agriculture. We use our box model to reject increasing fossil fuel emissions or decreasing hydroxyl radical sink as the dominant driver for increasing global methane abundance.

Methane (CH4) is the second-most abundant anthropogenic greenhouse gas and has global warming potential (GWP) of 28 over 100 y (1); as a result, CH4 has consequential near-term radiative effects and is a prominent target for mitigation (2). Following a short pause in growth from 1999 to 2006, both the abundance and growth rate of atmospheric methane have been increasing (3). During 2020–2022, the observed CH4 growth rate reached a record high since NOAA measurements began in 1983, averaging 15.4 ± 0.6 ppb yr?1 (4). Understanding the mechanisms driving this accelerated growth is essential for predicting its future climate impact and providing scientific support for climate mitigation strategies (2).

The carbon isotopic composition of atmospheric CH4 (?13CCH4) is a powerful tool for tracking the sources and sinks of atmospheric CH4. Different CH4 sources have distinctive ? 13CCH4 values: Microbial CH4 emissions (wetlands, livestock, landfills, etc.) have lower ?13CCH4 values (global mean of –62‰) than pyrogenic (biomass and biofuel burning, global mean of –24‰) and fossil fuel CH4 emissions (global mean of –45‰) (5). Various sinks of atmospheric CH4 also have distinctive isotopic effects. Therefore, combined observations of atmospheric CH4 mole fraction and ?13CCH4 can provide unique constraints on the changes of global CH4 sources and sinks during the post-2006 rapid CH4 growth.

The National Oceanic and Atmospheric Administration’s Global Monitoring Laboratory (NOAA/GML) has been carefully monitoring the global CH4 burden through the Global Greenhouse Gas Reference Network (GGGRN) for over four decades. The collaboration between NOAA/GML and the Institute of Arctic and Alpine Research (INSTAAR) at the University of Colorado Boulder has enabled ?13CCH4 measurements from the GGGRN since 1998, currently measuring weekly or biweekly from 22 globally distributed background sites (6). The dataset has been widely used for studying the evolution of global CH4 sources and sinks (7–9). Here, we report our most recent observations of atmospheric CH4 mole fractions and ?13CCH4 values through the end of 2022 and then use a box model to examine and quantify the contributions of potential drivers of the record-high CH4 growth rate.

[...]