Why methane is an underestimated greenhouse gas and how scientists are tracking its emissions

Where does methane come from and why is it dangerous?

In 2018, methane (CH4) for about 9.5% of all greenhouse gas emissions in

The USA accounted for the results of activitieshuman. Human activities related to methane emissions include leaks from natural gas production systems and livestock raising. Methane is also emitted from natural sources such as natural wetlands. In addition, natural processes in the soil and chemical reactions in the atmosphere help remove CH4 from the atmosphere. The lifetime of methane in the atmosphere is much shorter than that of carbon dioxide (CO2), but CH4 traps radiation more efficiently. The comparative exposure to CH4 is 25 times that of CO 2 over a 100-year period.

Globally, 50 to 65 percent of total CH4 emissions are from human activities.

  • Agriculture. Livestock such as cattle,pigs, sheep and goats produce methane as part of the normal digestion process. In addition, this gas is generated during the storage or handling of manure. Since humans raise these animals for food and other products, the emissions are thought to be human-related. When emissions from livestock and manure are combined, the agricultural sector is the largest source of methane emissions.
  • Energy and industry. Natural gas and oil systems are secondthe largest source of methane emissions. This gas is the main component of natural gas in the United States. Methane is emitted to the atmosphere during the production, processing, storage, transportation and distribution of natural gas, as well as during the production, processing, transportation and storage of crude oil. Coal mining is also a source of CH4 emissions.
  • Waste from homes and businesses. Methane is generated in landfills during decompositionwaste and wastewater treatment. Landfills are the third largest source of CH 4 emissions in the United States. Methane is also generated from domestic and industrial wastewater treatment and composting.

Methane is also emitted from a number of naturalsources. Natural wetlands are the largest source of CH4 emissions from bacteria that decompose organic materials in the absence of oxygen. Smaller sources include termites, oceans, sediments, volcanoes, and forest fires.

How to reduce methane emissions?

There are several ways to reduce methane emissions. EPA - US Environmental Protection Agency - has a number of voluntary programs to reduce CH4 emissions in addition to regulatory initiatives. In addition, the company supports the Global Methane Initiative. It is an international partnership that promotes global strategies to reduce methane emissions.

Emission source How to reduce emissions?IndustryModernization of equipment used forextraction, storage and transportation of oil and natural gas can reduce many leaks that contribute to methane emissions. Coal mine methane can also be captured and used for energy through the Natural Gas STAR and Coalbed Methane Outreach Program (CMOP) programs.AgricultureMethane from manure management methods canreduce and capture by changing the manure management strategy. In addition, changing animal feeding practices can reduce emissions from intestinal fermentation. Learn more about improved livestock practices by reviewing the EPA AgSTAR program.Waste from homes and businessesSince landfill methane emissions are the main source of gas emissions in the United States, emission control measures that capture gas from landfills can help in emission reduction strategies.

Why is it important to fight methane?

Although methane does not stay in the atmosphere like thisAs long as carbon dioxide, it is much more damaging to the climate at first because of how efficiently it absorbs heat. In the first two decades after the release, methane is 84 times stronger than carbon dioxide.

Since methane is so powerful and at the same time humanity has solutions that reduce its emissions, methane management is the fastest and most effective way to slow the rate of warming of the planet.

If methane is released into the air before use- for example, from a leaky pipe - it absorbs solar heat, heating the atmosphere. For this reason, it is considered a greenhouse gas such as carbon dioxide.

How to solve the methane problem?

Until recently, little was known aboutwhere the leaks occurred and how best to fix them. In 2012, EDF began a series of studies to better identify leaks and find solutions.

Summary of 16 studies across the US supply chainshows methane emissions significantly higher than originally estimated. In May 2016, the EPA approved the first ever national regulation to directly limit methane emissions from oil and gas operations, opening up a new opportunity to reduce climate pollution. For now, the US Environmental Protection Agency seeks to establish regulations that protect US residents from methane pollution.

EPA Project - Google Earth Outreach - Helpsvisualize climate-hazardous leaks found in local communities. Why is it important? Raising awareness of the magnitude and impact of methane leaks is essential for effective policy development.

To date, another technology has been created,which helps to identify traces of methane. A powerful new satellite has appeared in the sky to monitor emissions of methane, one of the key gases affecting human-induced climate change.

What developments are there to combat methane?

Newest Iris satellite for methane monitoring

The spacecraft known as Iris maydisplay methane plumes in the atmosphere with a resolution of only 25 meters. This makes it possible to identify individual sources of methane, for example, specific oil and gas facilities.

Iris was launched by the Canadian company GHGSat (Global Emissions Monitoring) in Montreal on September 2. It is a pioneer in a constellation of 10 spacecraft that will appear by the end of 2022.

Iris's first attempt to register a significant methane release.

Observations were carried out over Turkmenistan, ina region where large plumes from the oil and gas infrastructure were previously noted. The detection, superimposed on a standard aerial image, shows air methane concentrations above normal background levels.

“We still need to work on calibration,which will then allow us to check the detection threshold and the final performance of the satellite. But the image quality is phenomenal by any standard, ”GHGSat CEO Stéphane Germain told BBC News.

GHGSat is already working with operators regulatingauthorities and other stakeholders to characterize these emissions using a prototype satellite called Claire, which it launched in 2016. Iris's orbital presence provides the company with an additional stream of data that it now intends to interpret. at a new UK think tank to open in Edinburgh and London in the coming weeks.

“There is world-class capability in what we do in the UK,” explains Dr. Germain, “not only in analytics, but also in the spacecraft systems that interest us.”

Sentinel-5P satellite from ESA

GHGSat has recently been strengthening its ties with the European Space Agency, which operates the EU's Sentinel-5P satellite.

It also monitors methane by taking daily global snapshots of the gas. But at 7 km resolution, his data is much less telling than Iris and Claire data.


But add up if you use both satellites together, they form something like a dream team for methane exploration, scientists say.

“They (Sentinel-5P) can see the whole world everyoneday. We cannot do this. But we can see individual objects. They cannot do it. So, really, this is a fantastic combination, and it creates a very good relationship with the European Space Agency, and I think we are just starting to grow into something much more. "

GHG's next satellite, Hugo, is being tested and is expected to launch later this year.

The company recently received $ 30 million in additional funding that allows it to build three spacecraft that will follow Hugo into orbit.

The global methane problem. What is the difficulty of accounting for it?

Methane budget

Methane is a potent greenhouse gas and isthe second largest human-induced global warming factor after CO2. Per unit mass, methane is 84-86 times stronger than CO2 in 20 years and 28-34 times stronger in 100 years.

The global methane budget allows you to track where the methane is emitted from, how much is absorbed by “sinks” and therefore how much remains in the atmosphere.

The Methane Budget is an initiative of the Globalthe Carbon Project (GCP), an international research program that aims to “create a complete picture of the global carbon cycle”. Founded in 2001, GCP provides annual updates on global carbon emissions.

Methane is “a little more complicated,” explains Dr. Mariel Saunois, an assistant professor at the University of Versailles Saint-Quentin in France, who leads the global methane budget.

The difficulty is partly due to the fact that forcreating a methane budget requires lengthy model runs that take time. It would take too many resources for the scientific community to update the data every year. As a result, the methane budget is updated every two to three years.

There is a third publication that appeared in a whitepaper in Earth System Science Data and in an accompanying "forward looking" paper in Environmental Research Letters.

Dual approaches to methane budget

The global methane balance uses two different approaches to estimate sources and sinks.

  • The first approach is "bottom-up", whichfocuses on methane emissions at source. It uses emission data that are reported by individual countries in their national greenhouse gas inventories at the UN. These inventories cover anthropogenic sources such as fossil fuel use, animal husbandry, rice cultivation and landfills.

    These estimates are summed up with simulations of othersources of methane such as wetlands, forest fires and termites. For example, satellite data on the global area burned by fires are combined with models that “take into account the type of vegetation burned, the area burned and the duration of the fire, and the type of fire,” Sonua explains.

  • The second approach is called top-down. It starts by observing methane concentrations globally and works backwards, using simulations to estimate where they originated.

Neither approach is perfect, andthese two methods, according to scientists, are "incompatible". But the dual approach has its advantages. The top-down approach, says Dr. Sanua, “is a more reliable estimate of the global total” of methane emissions, but bottom-up estimates are used to determine emissions in specific regions and sectors.

For example, emissions from wetlands and freshwaterwater is particularly difficult to assess, which means "significant discrepancy" between descending and ascending numbers, says Sanua. In particular, this is due to the fact that the sources overlap, she adds, and therefore can be classified in more than one category.

Where is most methane?

Researchers say that in three regions -Africa and the Middle East, China, South Asia and Oceania - have seen the largest increases in methane emissions. In each case, emissions increased by 10-15 million tonnes between the 2000-06 average. and 2017

The next largest growth was 5.0-6.7 million tonnes in North America, and as the budget shows, mainly due to an increase of 4.4-5.1 million tonnes in the United States.

In contrast, Europe saw a modest reduction in emissions, by around 1.6-4.3 million tonnes, mainly due to lower emissions from agriculture.

This is contrary to the trend seen in other regions, with increased agricultural emissions being the main reason for the increase in total emissions in Africa, South Asia and Oceania.

For fossil fuels, the largest increasemethane emissions - 5-12 billion tons - were recorded in China, while in North America, Africa, South Asia and Oceania there was an increase of 4-6 million tons. Methane emissions from fossil fuels in the United States increased by 3.4-4.0 million tons.

It should be borne in mind, however, that recent studies have shown that despite the huge numbers, methane emissions from fossil fuels were "grossly underestimated."

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