Which Is Methane’s Role in Global Warming?

Methane is gaining attention for its significant role in global warming. Scientists are using satellites to track emissions, which are rising and projected to increase this century. Although methane concentrations are much lower than carbon dioxide levels (around 420 ppm), methane is much more potent. It is about 80 times more effective than carbon dioxide at trapping heat over a 20-year period. Methane is estimated to be responsible for one-third of global warming since the industrial era.

Currently, efforts have focused on preventing methane from entering the atmosphere. This includes targeting hotspots like oil and gas pipelines and landfills. However, these sources account for only 21% of total methane emissions. The remainder comes from broader societal sources, such as coal mines and livestock, as well as natural sources like swamps and thawing permafrost.

As emissions rise, there is increasing pressure to find ways to directly remove methane from the atmosphere. Gabrielle Dreyfus, chair of the NASEM committee and chief scientist at the Institute for Governance & Sustainable Development, emphasizes this need.

The good news is that methane, a primary component of natural gas, can be converted into carbon dioxide and water fairly easily. The challenge lies in finding ways to accelerate this oxidation process. “How do you engineer a device, building, leaf, or soil that makes that oxidation rate move faster?” asks scientist Jones.

The committee has identified five promising approaches for investigation:

1. Methane Concentration Machines: Devices that would gather and concentrate methane.
2. Methane Breakdown Technologies: Tools that would facilitate the breakdown of methane.
3. Oxidation Catalysts: Catalysts that could be added to surfaces in contact with air, such as wind turbine blades.
4. Ecosystem Tweaks: Modifications to ecosystems to increase the abundance of methane-digesting microbes.
5. Airborne Chemical Boosts: Strategies to enhance airborne chemicals like chlorine or hydroxyl ions to speed up methane breakdown.

Currently, no technology exists to tackle methane at levels below 1000 ppm, which is 500 times higher than atmospheric levels. The committee recommended that much of the funding focus on understanding basic methane dynamics, including how it moves through the atmosphere and ecosystems. They also called for studying social aspects, such as public involvement in discussions about acceptable technologies.

Since methane removal research is just starting, it may avoid some issues faced by other climate interventions. Sikina Jinnah, a committee member, notes that it’s crucial to involve social scientists early in the process.

Researchers are making progress in capturing methane from concentrated sources. Desirée Plata, a geochemist at MIT, plans to test a clay-based material at a coal mine. This material can trap and accelerate the breakdown of methane. She will extract methane-rich air from the mine shafts using large ventilation fans. If successful, this technology could help control emissions from mines, which contribute over 40 million tons of methane per year—about 10% of total human-caused methane emissions.

While it may be possible to remove methane from the air, it would be energy-intensive and inefficient. Plata advises focusing on high-concentration areas like coal mines, where methane levels can be 500 to 10,000 times greater. “It just doesn’t make sense to treat those lower levels,” she states.