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Author Topic: Toward Improved Discussions of Methane & Climate  (Read 40916 times)

GoSouthYoungins

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Re: Toward Improved Discussions of Methane & Climate
« Reply #100 on: July 15, 2020, 07:15:39 PM »
[Methane] is 28 times more powerful than CO2 at trapping heat[/b]

That's at least a 4x underestimation.  An "improved discussion of methane and climate" might want to start with a GWP1 for CH4.
big time oops

Simon

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Re: Toward Improved Discussions of Methane & Climate
« Reply #101 on: July 15, 2020, 08:57:46 PM »
Radiative forcings of CO2, CH4 and other greenhouse gases are given towards the bottom of this page

https://www.esrl.noaa.gov/gmd/aggi/aggi.html

CH4 is about a 1/4 that of CO2


Sciguy

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Re: Toward Improved Discussions of Methane & Climate
« Reply #102 on: January 29, 2021, 10:36:42 PM »
Methane emissions from coal mines are 50% higher than previously assumed.

https://phys.org/news/2021-01-methane-emissions-coal-higher-previously.html

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January 29, 2021
Methane emissions from coal mines are higher than previously thought
by Tom Rickey, Pnnl, Pacific Northwest National Laboratory

The amount of methane released into the atmosphere as a result of coal mining is likely much higher than previously calculated, according to research presented at the annual meeting of the American Geophysical Union recently.

The study estimates that methane emissions from coal mines are approximately 50 percent higher than previously estimated. The research was done by a team at the U.S. Department of Energy's Pacific Northwest National Laboratory, the U.S. Environmental Protection Agency and others.

The higher estimate is due mainly to two factors: methane that continues to be emitted from thousands of abandoned mines and the higher methane content in coal seams that are ever deeper, according to chief author Nazar Kholod of PNNL.

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The study is one of the first to account for methane leaking from old, abandoned mines. Kholod said that when a closed mine is flooded, water stops methane from leaking almost completely within about seven years. But when an abandoned mine is closed without flooding, as many are, methane leaks into the air for decades.

Here's a link to the study.

https://agu.confex.com/agu/fm20/webprogram/Paper667289.html

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Nazar Kholod1, Meredydd Evans1, Raymond Pilcher2, Volha Roshchanka3, Felicia Ruiz4, Michael Coté5 and Ron Collings5, (1)Pacific Northwest National Laboratory, Joint Global Change Research Institute, Richland, WA, United States, (2)Raven Ridge Resources, Grand Junction, CO, United States, (3)US Environmental Protection Agency, Climate Change Division, Washington, DC, United States, (4)US Environmental Protection Agency (former), Washington, DC, United States, (5)Ruby Canyon Engineering, Grand Junction, CO, United States
Abstract:
Coal mines are one of the largest sources of anthropogenic methane emissions. As the world produces more coal, coal mines get deeper every year, and methane emissions grow with the increasing mining depths. Mine operators also abandon coal mines, but coal strata in these old mines still emit methane into the atmosphere. This study uses measurement data on mine depth, gas content of coal, and other data from key coal producing countries to estimate methane emissions from active (CMM) and abandoned mines (AMM). This methodology can help more accurately estimate global emissions from coal mining because it takes a comprehensive look at emissions, even in cases where there are gaps in direct measurement and official reporting. For example, few countries measure their abandoned mine methane emissions. A detailed assessment shows that coal mining-related methane emissions are higher than previous studies have showed. The methodology can also be used to estimate CMM and AMM emissions through 2100 under various coal production scenarios and to understand the potential range of uncertainty in current emissions estimates. To reduce uncertainties in methane emission estimates, more efforts are needed to improve reporting and cross-checking through measurement.




Sciguy

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Re: Toward Improved Discussions of Methane & Climate
« Reply #103 on: February 12, 2021, 09:45:54 PM »
New satellites are capable of detecting methane leaks from oil and gas facilities as they occur.

https://www.bloomberg.com/news/articles/2021-02-12/new-climate-satellite-spotted-giant-methane-leak-as-it-happened

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New Climate Satellite Spotted Giant Methane Leak as It Happened

Equipment and software operated by GHGSat picked up eight simultaneous plumes from a field in Turkmenistan.
By Naureen S Malik
February 12, 2021

Methane leaks from at least eight natural gas pipelines and unlit flares in central Turkmenistan earlier this month released as much as 10,000 kilograms per hour of the supercharged greenhouse gas, according to imagery produced by a new satellite capable of detecting emissions from individual sites.



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The pixelated snapshot showing the eight simultaneous leaks within just 20 square miles is an alarming harbinger of what could be revealed now that satellite technology is capable of pinpointing emissions from specific wells, pipelines, and mines. GHGSat launched its first satellite in 2016, but it wasn’t until last September that it had one in orbit capable of picking out individual wells. In the fourth quarter of 2020 alone, Germain said, it detected hundreds of leaks.

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Part of GHGSat’s mission is to work with refinery and pipeline operators to stop methane leaks sooner to minimize the damage. Its ability to communicate with Turkmenistan is limited, said Germain, and time is of the essence for stopping large leaks. The satellite company has been relying on diplomatic channels through the Canadian government to try to reach the operator, but with no success so far. GHGSat declined to disclose precise coordinates for the leaks, which came from the Galkynysh Gas Field, in order to give the Turkmenistan government space to address the situation.

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Competitors are joining the emerging field of leak detection at an accelerating rate. Bluefield Technologies Inc., for instance, was the first to identify a massive plume just north of Gainesville, Florida, in July 2020, using publicly available data captured by the ESA. A Bloomberg News report subsequently identified the likely source, a gas compressor station owned by Florida Gas Transmission, which prompted a U.S. Environmental Protection Agency investigation into a possible violation of the Clean Air Act.

GHGSat looked at the same data and, using its proprietary technology, was able to trace the leak directly to the compressor station, confirming the source, Germain said. That leak, which took place over at least two days in early May, was much larger than the leaks detected this month. According to GHGSat’s estimates, it released methane at a rate equivalent to 1.25 million cars per hour.

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In Central Asia, where Turkmenistan is located, Germain said methane emissions rose three-fold between March 2020 and the end of the year compared to the same period a year earlier.

Sciguy

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Re: Toward Improved Discussions of Methane & Climate
« Reply #104 on: February 12, 2021, 09:53:04 PM »
^^^
For context, Turkmenistan is 4th globally in emissions from oil and gas facilities, after Russia, the USA and Iran.

https://www.ft.com/content/54aff00d-8108-4d01-9090-5d0273b55bb0

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Climate graphic of the week: the biggest methane emitters
Energy sector must cut potent gas release by almost a third by 2025 to meet sustainable goals



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The amount of powerful methane gas the US agricultural and energy sector spilled into the atmosphere last year again neared the top of the global charts, coming second only to Russia.

Venting and shale gas leaks from the US shale industry continued to drive the country’s elevated methane emissions, according to the latest data from the International Energy Agency.

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The US accounted for 16 per cent of the total of 72m tonnes of methane emitted by the global oil and gas industry in 2020. After Donald Trump rolled back rules in the US that forced producers to monitor and fix leaks, President Biden has vowed to again clamp down on emitters.

Sciguy

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Re: Toward Improved Discussions of Methane & Climate
« Reply #105 on: February 26, 2021, 12:19:51 AM »
A recently published study found that human emissions (from coal mines in China and oil and gas fields in North America) are responsible for the recent uptick in methane emissions (since 2007).  They found "There is no evidence of emission enhancement due to climate warming, including the boreal regions, during our analysis period."

https://www.jstage.jst.go.jp/article/jmsj/advpub/0/advpub_2021-015/_article

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Emissions from the Oil and Gas Sectors, Coal Mining and Ruminant Farming Drive Methane Growth over the Past Three Decades
Naveen CHANDRA, Prabir K. PATRA, Jagat S. H. BISHT, Akihiko ITO, Taku UMEZAWA, Nobuko SAIGUSA, Shinji MORIMOTO, Shuji AOKI, Greet JANSSENS-MAENHOUT, Ryo FUJITA, Masayuki TAKIGAWA, Shingo WATANABE, Naoko SAITOH, Josep G. CANADELL

Abstract

 Methane (CH4) is an important greenhouse gas and plays a significant role in tropospheric and stratospheric chemistry. Despite the relevance of methane (CH4) in human-induced climate change and air pollution chemistry, there is no scientific consensus on the causes of changes in its growth rates and variability over the past three decades. We use a well-validated chemistry-transport model for simulating CH4 concentration and estimation of regional CH4 emissions by inverse modelling for the period of 1988-2016. The control simulations are performed using a seasonally varying hydroxyl (OH) concentrations and assumed no interannual variability. Using inverse modelling of atmospheric observations, emission inventories, a wetland model, and a δ13C-CH4 box model, we show that reductions in emissions from Europe and Russia since 1988, particularly from oil-gas exploitation and enteric fermentation, led to decreased CH4 growth rates in the 1990s. This period was followed by a quasi-stationary state of CH4 in the atmosphere during the early 2000s. CH4 resumed growth from 2007, which we attribute to increases in emissions from coal mining mainly in China and intensification of ruminant farming in tropical regions. A sensitivity simulation using interannually varying OH shows that regional emission estimates by inversion are unaffected for the mid- and high latitude areas. We show that meridional shift in CH4 emissions toward the lower latitudes and the increase in CH4 loss by hydroxyl (OH) over the tropics finely balance out, which keep the CH4 gradients between the southern hemispheric tropical and polar sites relatively unchanged during 1988-2016. The latitudinal emissions shift is confirmed using the global distributions of the total column CH4 observations by satellite remote sensing. There is no evidence of emission enhancement due to climate warming, including the boreal regions, during our analysis period. These findings highlight key sectors for effective emission reduction strategies toward climate change mitigation.

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Between the period 1999-2006 and 2007-2016, the a posteriori emission shows ~30 Tg yr-1 increase in the global emissions (Fig. 5c and Table 1), and ~24Tg yr-1 of the global increase occurred in Asia (Fig. 12).The East Asia, West Asia, South Asia, and Southeast Asia regions accounted for 28%, 19%, 18%, and 19% of the global a posteriori emission increase from 1999-2006 to 2007-2016, respectively (Fig. 12f,c,h,j).The EDGARv4.3.2 inventory suggests that the coal sector over East Asia, West Asia, Southeast Asia, and ruminant farming sector over Southeast Asia drive a large part of emission increase from 1999-2006 to 2007-2016 (Fig. 5f,c,j,h).The a posteriori emission trend over East Asia shows an excursion from the continuous (extrapolated) increase of that of the a priori after 2012 (Fig. 12f). One possible explanation is that emissions from abandoned coal mines in East Asia may have ceased, in agreement with that is suggested by the d13C-CH4 model.Themost recent inventory (EDGARv5.0) emissions from coal mining indeed show a slowdown in the rate of increase, at 2.6% yr-1during 2012-2014 and by 3% yr-1 during 2014-2015, relative to a rate of increase of 5.7 % yr-1during 2003-2011 (Crippa et al. 2020).

The sources of the North American increase are uncertain and may be due to increased emissions from wetlands. The huge increases in fracked oil and gas wells and the documented problems they have with fugitive emissions may indicate that the oil and gas industry is responsible.

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More recently, a posterioriemission over Temperate North America(Fig. 12e)shows 9.8Tg yr-1 increase (from 30 Tg yr-1 in 2010 to 39.8 Tg yr-1in 2016) between 2010 and 2016, which is consistentwith the increase in wetland emission by VISIT model and fugitive emissionsinEDGARv4.3.2inventory during the same period (Fig. 1e). This emission increase outside fast growing economies may have helped to sustain the regrowth in the 2010s. However, the increase in emissions from fugitive sources from the United States are uncertain (Sheng et al. 2018; Lan et al. 2019), and a broader assessment is needed for the wetland emission increase.

The higher northern regions show a systematic decrease in a posteriori emission. The European emissions gradually decreased between 1988 and 2010(Fig. 12b) due to the decline in ruminant farming emissions (Fig. 1b), and Russian emission decreased between 1988 and 2000 (Fig. 12d) due to the decrease infugitive emissions (Fig. 1d). TheFAOSTAT statistics suggest that the cow and cattle population decreased largely over the western Europe (FAOSTAT 2018). As reported by some previous studies (Sweeney et al. 2016; Thompson et al. 2018), we did not find any detectable increase in natural CH4 emissions from the wetlands and other ecosystems in the northern high latitudes, e.g., the Boreal North America and Russia, despite the increase in annual mean temperature by ~1.2oC/decade for the period of 1985-2015 over the Arctic region (Sweeney et al. 2016). These regions are expected to release CH4 in response to future global warming in the boreal zones (Anthony et al. 2018).