First direct observations of methane's increasing greenhouse effect at the Earth's surface

April 2, 2018, Lawrence Berkeley National Laboratory
The scientists used radiometers, shown here, to isolate the signal of methane's greenhouse effect. Radiometers are among the many instruments at ARM's Southern Great Plains observatory that the team utilized as part of this study. Credit: ARM Climate Research Facility

Scientists have directly measured the increasing greenhouse effect of methane at the Earth's surface for the first time. A research team from the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) tracked a rise in the warming effect of methane - one of the most important greenhouse gases for the Earth's atmosphere - over a 10-year period at a DOE field observation site in northern Oklahoma.

These findings were published online April 2 in the journal Nature Geoscience in an article entitled "Observationally derived rise in surface forcing mediated by water vapour trends." The paper indicates that the greenhouse from methane tracked the global pause in methane concentrations in the early 2000s and began to rise at the same time that the concentrations began to rise in 2007.

"We have long suspected from laboratory measurements, theory, and models that methane is an important greenhouse gas," said Berkeley Lab Research Scientist Dan Feldman, the study's lead author. "Our work directly measures how increasing concentrations of methane are leading to an increasing greenhouse effect in the Earth's atmosphere."

Gases that trap heat in the atmosphere are called greenhouse gases, in large part because they absorb certain wavelengths of energy emitted by the Earth. As their atmospheric concentrations change, the scientific community expects the amount of energy absorbed by these gases to change accordingly, but prior to this study, that expectation for methane had not been confirmed outside of the laboratory.  

This graph shows a time series of the greenhouse effect of methane in Watts per square meter, measured at the Earth's surface over a ten-year period at a research site in northern Oklahoma. The red line is the trend in the time series, and the grey shading represents uncertainty. Credit: Berkeley Lab

The scientists analyzed highly calibrated long-term measurements to isolate the changing effect of methane. They did this by looking at measurements over the wavelengths at which methane is known to exert its and coupled those with a suite of other atmospheric measurements to control for other confounding factors, including water vapor.

This study was enabled by the comprehensive measurements of the Earth's atmosphere that the DOE has routinely collected for decades at its Atmospheric Radiation Measurement (ARM) facilities, and conversely, would not be possible without such detailed observations.

The DOE ARM program manages and supports three long-term atmospheric observatories - the Southern Great Plains observatory in Oklahoma, the North Slope of Alaska observatory in far-northern Alaska, and the Eastern North Atlantic observatory on the Azores Islands. The program also deploys three ARM mobile facilities and several ARM aerial facilities. Together, these assets enable scientists to perform highly-detailed, targeted investigations to advance the fundamental scientific understanding of the Earth system.

The researchers believe this type of direct field observation can provide a more accurate and complete picture of the relationship between atmospheric and their warming effect on Earth's surface.

Explore further: New research shows fertilization drives global lake emissions of greenhouse gases

More information: Observationally derived rise in methane surface forcing mediated by water vapour trends, Nature Geoscience (2018). nature.com/articles/doi:10.1038/s41561-018-0085-9

Related Stories

Thawing permafrost produces more methane than expected

March 20, 2018

Methane (CH4) is a potent greenhouse gas that is roughly 30 times more harmful to the climate than carbon dioxide (CO2). Both gases are produced in thawing permafrost as dead animal and plant remains are decomposed. However, ...

Little growth observed in India's methane emissions

October 10, 2017

Methane is the second most powerful greenhouse gas and concentrations are rising in the atmosphere. Because of its potency and quick decay in the atmosphere, countries have recognised that reduction of methane emissions are ...

Recommended for you

Amazon River pirating water from neighboring Rio Orinoco

August 16, 2018

The Amazon River is slowly stealing a 40,000-square-kilometer (25,000-square-mile) drainage basin from the upper Orinoco River, according to new research suggesting this may not be the first time the world's largest river ...

10 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

Parsec
5 / 5 (3) Apr 02, 2018
It is hard to reconcile climate change denial with the existence of direct evidence of warming due to each component. People apparently are willing to accept a logical black hole in their reasoning process for the relative comfort of tribal and ideological purity.

It is quite difficult to imagine, at least to me, how this kind of twisted thinking is more comfortable than embracing reality, but I guess it takes all kinds.
Turgent
3 / 5 (2) Apr 02, 2018
What the hell is going on. This is a US DOE funded paper and it is locked away behind a paywall. By law this property to taxpayers and belongs in public domain and posting it on arxiv.org or elsewhere would be the thing to do.

"Scientists have directly measured the increasing greenhouse effect of methane at the Earth's surface for the first time." It would be immensely interesting to see their methodology and how this compares and relates to CO2.

robweeve
5 / 5 (2) Apr 02, 2018
Quick, tell Pruitt!
aksdad
1 / 5 (6) Apr 02, 2018
It is hard to reconcile climate change denial with the existence of direct evidence of warming due to each component

It IS hard...for someone who accepts the entire premise unquestioningly. Many of us skeptics, however, have a more informed and nuanced understanding because we've taken the time to understand the theory, how it's been validated, and what observations show.

The results of most published studies are never replicated and verified (despite the belief that "peer review" means it's been validated) so it remains to be seen how well the researchers did their work. Behind a paywall, so good luck. Regardless, all they've done is (apparently) measure what radiative transfer calculations predicted. It doesn't tell us where the methane came from.

Carbon dioxide is different. No one has directly measured heat trapped in the atmosphere by CO2, which also overlaps water vapor. We know humans increase CO2, but we don't know by how much or how much warming happens.
Turgent
1 / 5 (2) Apr 02, 2018
Carbon dioxide is different. No one has directly measured heat trapped in the atmosphere by CO2, which also overlaps water vapor. We know humans increase CO2, but we don't know by how much or how much warming happens.


More than anything else that is what I would like to see'
ddaye
5 / 5 (3) Apr 02, 2018
It is quite difficult to imagine, at least to me, how this kind of twisted thinking is more comfortable than embracing reality, but I guess it takes all kinds.
Don't try to imagine what you can't --do what Newton did about the nature of gravity, stick to explaining its effects. The effects of embracing contra-reality on climate change include advancing the forces that own and operate the planet. Those forces have many rewards to spread around to supporters, both financial and cultural. In the lives of humans, embracing reality is very often disadvantageous when rejecting it can bring opportunity and community.
jonesdave
4.3 / 5 (6) Apr 02, 2018
We know humans increase CO2, but we don't know by how much.....


Well, one way would be to measure pre-industrial CO2 levels, and then compare them to current levels. Given that we see little change in solar activity over that time frame (and wouldn't expect to), then that should give us a pretty good estimate of how much of the CO2 increase is anthropogenic. That would be pretty much all of it.
Parsec
5 / 5 (5) Apr 03, 2018
"We know humans increase CO2, but we don't know by how much....."

Actually... the fact is that CO2 from biological processes has a different isotropic signature than that from geological ones. Life has a preference for one carbon isotope over the others.

So we can tell approximately how much of the CO2 in the atmosphere is from burning oil and gas (biological origins) and how much is coming from natural sources.
antigoracle
1 / 5 (2) Apr 03, 2018
Benni
1 / 5 (2) Apr 03, 2018
Actually... the fact is that CO2 from biological processes has a different isotropic signature than that from geological ones. Life has a preference for one carbon isotope over the others.


Wrong, it is 14C, 13C and 12C, Any relation to Carbon Dioxide is simply INFERRED from these isotopes of CARBON.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.