‘Over 20 years, methane warms Earth 80 times more than CO2 — but it offers us opportunities'

Over 20 years, methane warms Earth 80 times more than CO2 — but it offers us opportunities’

Robert C. Stowe is Executive Director of the Harvard Initiative on Reducing Global Methane Emissions. Speaking to Srijana Mitra Das at Times Evoke from COP29 in Baku, Azerbaijan, he discusses the urgency — and methods — to lower methane releases:

What are the most profound impacts of methane on the environment?

Methane (CH4), like carbon dioxide (CO2), is a greenhouse gas — it warms Earth. However, it is different from CO2 in two ways — it is a more powerful warming agent. Over 20 years, methane is 80 times more powerful than CO2 in retaining heat near Earth’s surface. Also, methane is very short-lived compared to CO2 — it disappears in just a few decades, rather than hundreds of years like CO2. These two scientific facts combined make methane a terrific opportunity for climate action.

By reducing methane emissions, we can have an immediate impact on global average surface temperature, keeping 2°C or even the 1.5°C target within reach.

WILL A NEW RICE RISE? For centuries, farmers have grown paddy by flooding their fields — today, however, this is a major contributor to both methane emissions and water loss, spurring research on alternative ways of farming rice (Photo Getty images and iStock)

What are the most important sources of methane emissions?

To start, there is energy. Natural gas is basically methane to a close approximation — when it leaks into the atmosphere, whether from fracking or other kinds of oil and gas production, this is methane escaping. There is often some confusion about flaring here. At times, in the production of oil, either the oil company doesn’t care about the natural gas or it doesn’t have the pipeline capacity to get it to market — so, it burns it at the production site, as with flares seen in oilfields. This actually turns the methane into carbon dioxide and other byproducts. However, a lot of the natural gas doesn’t get combusted, so there is still methane leak.

Another source is agriculture. There are two distinct areas within agriculture contributing to methane emissions. One is livestock, particularly ruminants, which produce methane during digestion. Most of this methane comes from cattle raised for the dairy and meat industries. The other significant area is paddy rice production. There are two types of rice cultivation: flooded and dry upland. The flooded or paddy rice method generates a substantial amount of methane. Waste and landfills also contribute to methane emissions. Disposing of organic matter, such as food waste and plant debris, in landfills results in significant methane production. Additionally, a fair amount of methane emissions comes from coalmines operating in certain parts of the world.

You’ve described a wide range of sources — what are some remedial measures to reduce CH4 emissions?

Given the diversity of sectors contributing to methane emissions, mitigation approaches vary significantly depending on the technologies, economics, and other factors involved. In many ways, the oil and gas sector is the easiest to address. Once a methane leak is identified, fixing it is relatively straightforward. A portfolio of technologies, including satellites and handheld devices, is now available to detect such leaks, and these technologies are constantly improving. While addressing leaks involves some cost, natural gas producers often recover this expense because the previously lost gas can now be captured and sold.

For livestock, ongoing research focuses on developing feed additives that can influence cattle digestion and reduce methane emissions. Many startups are exploring the use of Asparagopsis, a specific type of seaweed, as a promising solution. Additionally, adjusting the ratio of pasture feed to processed feed is another potential strategy to mitigate emissions.

In the case of paddy rice, water management techniques are being explored to reduce methane emissions. Flooding the rice fields constantly may not be necessary, and reducing water usage at various growth stages can help lower emissions. Furthermore, research is underway on developing rice strains that produce less methane, which could offer a long-term solution to emissions from this sector.

Importantly, methane is formed from the decomposition of organic matter in the absence of oxygen. This process, known as anaerobic digestion, produces methane. While the exact chemistry varies across sectors, the underlying principle remains the same. By exposing organic matter to oxygen, the amount of methane produced can be significantly reduced.

In waste management, a crucial step is to keep food and other organic matter out of landfills. If this cannot be achieved, the next best approach is to capture methane from waste sites. This is often done using PVC pipes placed atop landfills to collect the emitted gas. However, it is far more effective to prevent organic material from reaching these sites altogether. Ideally, organic waste would be composted, allowing decomposition to occur in the presence of oxygen, thereby mitigating methane emissions.

With such pressing impacts, which international agreements govern this area?

The most significant agreement addressing methane emissions is the Global Methane Pledge (GMP), introduced by the European Union and the United States at COP26 in 2021. To date, 159 countries have signed this pledge, which aims to reduce global methane emissions by 30% below 2020 levels by 2030. However, the GMP does not impose national targets; instead, each country commits to contributing as much as it can. While China and India have not signed the pledge, this does not mean they are not taking steps to reduce methane emissions.