When it comes to emissions, most of us are aware of CO2. But there are other greenhouse gases we need to think about too, such as nitrous oxides, sulfur oxides, black carbon, and hydrofluorocarbons. Chief among other gases to consider is methane. The atmospheric concentration of methane is increasing faster now than at any time since the 1980s, and methane has more than 80 times the warming power of carbon dioxide over the first 20 years after it reaches the atmosphere.
However, methane also presents great opportunities. Reducing methane emissions quickly is one of the fastest opportunities we have to immediately slow the rate of global warming, buying us more time for decarbonisation. This can produce immediate climate benefits that CO2 reductions alone can’t.
Here’s what you need to know.
What is methane
Methane is a greenhouse gas made up of one atom of carbon and four atoms of hydrogen (CH4). It’s the main component of natural gas, with a chemical shape that’s incredibly effective at trapping heat. Since pre-industrial times methane has accounted for at least 25% of the planet’s warming.
While CO2 levels in the atmosphere are over 200 times higher than methane, in the first 20 years after release methane is around 80 times more powerful at trapping heat. However, methane also breaks down more quickly than CO2, which can last in the atmosphere for centuries. After 12 years 80 – 89% of methane is removed by oxidation with tropical hydroxyl radicals (OH), a process known as hydroxyl oxidation. Methane only significantly warms the atmosphere for this short period of time, which is why it’s considered a short-lived climate pollutant (SLCP). That being said, when methane breaks down it eventually transforms into CO2, which also isn’t particularly helpful in the atmosphere. What this short lifespan does mean, however, is that curbing methane emissions has powerful potential when it comes to decarbonisation, as we could see rapid, short-term emissions gains while working on overall CO2 emissions.
Plus, methane is the primary contributor to the formation of ground-level ozone, a pollutant that can cause 1 million premature deaths annually due to exposure. Because it’s often paired with other toxic pollutants such as benzene, formaldehyde, and ethylbenzene, methane has major health impacts on millions of people who live near oil and gas operations.
The main sources of human-related methane are the fossil fuel industry, which accounts for 34% of total emissions, agriculture, which accounts for 40%, and the waste sector which accounts for 20%. Within agriculture, livestock is the is responsible for 32% of methane emissions.
At COP26 more than 100 countries, representing almost 50% of global methane pollution levels, committed to a voluntary Global Methane Pledge to reduce levels by at least 30% by 2030. Reducing methane emissions associated with human activity by 50% over the next 30 years could mitigate global temperature change by 0.2°C by 2050. The reduction in ground-level ozone would also prevent 260,000 premature deaths, 775,000 asthma-related hospital visits, 73 billion hours of lost labour from extreme heat and 25 million tonnes of crop losses per year.
Methane from livestock
Methane that comes from ruminant animals (eg cattle) or wetlands, is known as biogenic methane.
Researchers at New Zealand’s largest Crown Research Institute, AGResearch, found that regardless of which end it comes out, each cow produces between 130 and 230 litres of methane per day. Considering there are more than 1.3 billion cows on the planet, this adds up fast
When talking about methane it’s helpful to specify sources, because biogenic methane is specifically derived from atmospheric carbon such as CO2, returning back to the atmosphere when it breaks down into CO2 again. As part of the biogenic carbon cycle, plants absorb CO2, harnessing the energy of the sun to create carbohydrates such as cellulose. This cellulose is a key feed ingredient for ruminant animals, who then emit a portion as methane. After 12 years the methane is converted into carbon dioxide through hydroxyl oxidation. Carbon that enters the air is carbon that was already there prior to being consumed by an animal, making it recycled.
This has led people to argue that warming caused by biogenic methane can be neutral. Due to its short lifespan in the atmosphere methane is known as a flow gas as it’s being destroyed at the same time as being emitted. While biogenic and methane from fossil fuels are chemically identical, the resulting CO2 from oxidation has a different warming impact. The biogenic carbon from cattle and wetlands is returned to the atmosphere where it started, while fossil carbon is brand new atmospheric carbon, and hence, new warming.
But both of these also have to be considered in a context where we have too much carbon in the atmosphere already. It’s clear that, as well as reducing future emissions, we need massive efforts to draw down carbon that’s already in the atmosphere. We can’t really argue that carbon is neutral when it’s cycling in a system that is already imbalanced, so this can’t be used as an excuse for massive industrial agriculture.
Reducing biogenic methane
UNEP Food Systems and Agriculture Advisor James Lomax says the world needs to begin by “rethinking our approaches to agricultural cultivation and livestock production.” That includes leveraging new technology, shifting towards plant-rich diets and embracing alternative sources of protein.
There are many options being explored including: farmers providing animals with more nutritious feed so that they are larger, healthier and more productive, scientists experimenting with alternative feeds to reduce methane, and looking at ways to manage manure more efficiently by covering it, composting it, or using it to produce biogas. Overall, however, this is one of the most convincing arguments to reduce or cut out eating meat, in particular beef. Plant-rich diet options, whenever accessible, will need to increasingly become the cultural norm in order to reduce such high levels of methane production.
Alongside livestock, paddy rice cultivation accounts for another 8% of methane emissions, as fields are flooded which prevents oxygen from penetrating soil, creating perfect conditions for methane-emitting bacteria. Here, experts have recommended alternate wetting and drying approaches, irrigating and draining throughout the growing season to limit methane without impacting yield. This could halve emissions while also requiring one-third less water.
Overall, it’s worthwhile to reduce biogenic methane emissions from animal agriculture as much as possible, as it can buy time for the world to develop climate justice solutions that focus on overall emissions and decarbonisation.
Methane from fossil fuels
Fossil methane is also extremely important to talk about. Efforts to reduce biogenic methane are key, but they can’t distract us from the critical need to reduce emissions from fossil fuels. Much like CO2, methane from fossil fuel production is extracted from the earth and therefore new to the atmosphere. Plus, methane emissions from fossil fuel extraction have been severely underestimated.
Oil, gas and coal production are the largest industrial sources of methane emissions. Research shows that a relatively small number of ‘super-emitters’ are responsible for a significant share of methane emissions, particularly in the oil and gas industry.
Coal is the worst offender; it leaches both carbon dioxide as well as methane, making it the number one priority to phase out. Oil production is a big problem too, in part because producers don’t face much regulatory or economic pressure to recapture the extra gas. Even when industry is trying to capture and sell natural gas, producers lose methane throughout its extraction and transportation. It leaks out as producers pipe the gas to compressor stations, process it for shipment, ship it hundreds of miles by pipeline to a refinery, and transport it to the consumer in the form of liquefied natural gas, plastic, petrochemicals, or the gas that lights up ovens in homes and apartments.
Methane is a key by-product of extracting and processing natural gas. Recent research from EDF found that the U.S. oil and gas industry was emitting at least 13 million metric tons of methane a year, about 60% more than the Environmental Protection Agency estimated at the time.
Since 2013, at least 45 scientific papers have highlighted the disproportionate role of oil and gas operations, according to a review by the advocacy group Climate Nexus.
Unlike strategies to curb carbon dioxide emissions, such as carbon capture and storage, many of those to reduce methane are affordable. The International Energy Agency estimates that worldwide, the oil and gas industry can achieve a 75% reduction using technologies available today, two-thirds of it at no net cost.
Reducing methane across the world
A study from EDF scientists found that tackling methane emissions across multiple sectors can slow the current rate of warming by 30%.
Countries have implemented a variety of policies, such as setting industry-specific standards, requiring companies to report their emissions, and taxing emissions. In its most recent five-year plan, China, the world’s top methane emitter, mentioned reducing methane for the first time. In 2020, the European Commission also adopted a methane strategy; in December 2021 this introduced regulation on reducing methane in the energy sector, including:
- Improved measurement, reporting and verification of methane emissions
- Mandatory leak detection and repair
- A ban on venting and flaring
The goal is to understand where methane is emitted and how much. Oil and gas companies would be required to frequently survey equipment to detect leaks, repair them immediately, and monitor to ensure repairs are successful. Venting and routine flaring are also completely banned, with venting only allowed in unavoidable circumstances for safety reasons and flaring only if re-injection, utilisation on-site or transport of the methane to a market aren’t possible.
Suggestions for other industries to curb methane also include:
- Coal mining: the majority of coal-mine-methane (CMM) emissions are produced by either working or abandoned deep mines. It’s argued that technology can be used to capture methane from these coal mines but, as coal is so highly polluting, a complete phase-out of coal as fast as possible will also deal with this issue.
- Solid waste: most methane emissions from waste originates in landfills and open dumps, where anaerobic organic material generates methane over time. It’s argued this methane can be captured for energy or to produce fertiliser.
- Wastewater: wastewater emits methane from the breakdown of organic material in wastewater streams. Emissions could be reduced through building out modern sanitation infrastructure and technology, while biosolids responsible for producing methane could be collected for fertiliser.
- Wetlands: when plants and other organic matter decompose anaerobically (without oxygen) underwater in wetlands, swamps and marshes, they produce up to 70% of the natural methane in the atmosphere. Maximum methane production is found at temperatures between 37 – 45°C, meaning an increase in global temperature may also increase methane production in wetlands.
- Permafrost: there are huge amounts of methane locked under the oceans and within Arctic permafrost. Under very low temperatures, and/or high pressures, methane gas combines with water to form a solid structure, with methane trapped within a crystal structure of frozen water. When permafrost thaws and oceans warm due to climate breakdown, huge amounts of methane could be released.
These last two must both be tackled through mass efforts to decarbonise and draw down carbon. Reducing the impacts of warming and removing human-caused emissions from the atmosphere will be key.
We need to use every tool available to us to pursue climate justice. As well as lifestyle changes when available to you (eg reducing beef consumption), it’s clear that efforts need to be channelled into tackling the fossil fuel industry at each and every level. If you want to get involved, join your local climate action group today, or join Stop Cambo who campaign against new oil and gas in the UK.