Christian Roselund: Why do you think we are seeing this methane moment right now?
Deborah Gordon: In the 1990s, when climate change became a major concern and the UN set out to address greenhouse gas (GHG) emissions, they focused on CO2 as the priority pollutant. Thus, CO2 has been most closely tracked to mitigate climate change over the last 30 years.
Back then, not much attention was paid to short-lived climate forcers like methane. These pollutants don’t last long in the atmosphere, but they pack a huge climate punch. Conversely, each molecule of CO2 is not very powerful, but it is emitted in massive volume and lasts in the atmosphere for hundreds of years. Prioritizing CO2 seemed sound at the time. Had we succeeded during the 20th century in significantly cutting CO2, we wouldn’t be facing the climate problems that plague us today.
Thus, the overriding climate goal initially focused on stopping CO2 from building up in the atmosphere. CO2-focused emissions inventories, reporting protocols, and mitigation strategies were established. Today’s mounting fires, freezes, floods, and other climate devastation, however, are calling re-prioritizing short-term climate drivers with all eyes on methane.
Instead of dipping, atmospheric methane concentrations are rapidly increasing. Oil and gas systems are a major cause. A decade ago, fracking methane-concentrated oil and gas took off, just as we thought the world was running out of these resources. So, instead of rushing to find low-GHG substitutes for disappearing oil and gas, we are now wrestling with their abundance. This is pumping a lot more methane into the atmosphere.
The intensifying climate suffering that’s going on now is being driven by methane. While we must continue to reduce CO2, it is now methane’s moment. And there are serious efforts underway to double down on mitigating methane.
Roselund: Let’s talk about intensities. On its website, EPA lists the 100-year greenhouse gas intensity of methane versus CO2, and you have to do a bit of digging to find the 20-year intensity, which is much higher. Yet a lot of people are citing the 20-year intensity for the exact reason that you stated—this climate forcing. Why has it been so difficult to agree on a standard timeframe to measure greenhouse gas intensity by?
Gordon: Because climate change is recognized as a global pollution problem, you need to have international agreement to address it. In other words, if one country reduces its GHGs and other increases its emissions by the same amount, the climate is no better off.
As such, decades ago, the United Nations (UN) asked countries to calculate their emissions baselines and make reduction pledges. In this process, the UN established the use of a 100-year global warming potential (GWP) to factor in higher climate forcing from non-CO2 emissions. They selected a century because CO2 remains in the atmosphere at least that long. However, this timeframe significantly undercounts the climate damage from methane, which only lasts in the atmosphere trapping immense heat for about a decade.
The 100-year global warming potential for methane that’s used by the UN today dates back to 2007, even though scientists continue to ratchet it up the more they learn about methane’s true warming power. But for the benefit of global accords like the Paris climate agreement, polluters have been sticking with an outdated 100-year time frame that stymies near-term methane mitigation.
Roselund: How does methane work in the atmosphere and why is even a 20-year global warming potential inadequate to capture what’s actually going on in terms of warming?
Gordon: Methane is 120 times more powerful than CO2 in warming the planet, as soon as it’s emitted. The scientific curve of methane’s climate warming capacity, or climate forcing, begins at 120 more than CO2. The curve then dips down over time as methane chemically breaks down and transforms. But the lifetime of the methane molecule is only about 12 years. Decades out, most of the methane emitted eventually converts into CO2.
Here’s an easy way to picture the warming power of methane.
If carbon dioxide is one blanket wrapped around the planet, methane, as soon as it’s emitted, piles on 120 blankets that warm the Earth. Imagine being in your bed with 120 blankets on top of you, bearing the intense heat that builds up. Even as methane nears the end of its life in a decade, it’s still 100 times more warming than CO2.
In addition to oil and gas production, processing, and shipping, methane is also emitted by landfills and livestock operations. Climate solutions rest on avoiding methane emissions from these sources. Today, we do not have a sensible policy construct for both avoiding methane in the short term and managing CO2 in the long-term. Instead, current climate policy making efforts are challenged by trying to simultaneously avoid and mitigate different emissions with different potency over different time frames. This makes conventional 100- and 20-year GWPs inadequate to capture what’s actually going on in terms of warming.
Roselund: By having a supercharged warming over short term, are we putting ourselves in greater danger of having these negative feedback loops, say from melting Arctic permafrost or other sorts of problems?
Gordon: Cutting methane now presents the opportunity for short-term cooling, because you’re basically throwing the blankets off the bed. By reducing methane emissions, we literally shed layers of warmth out of the atmosphere very quickly, which buys us time to durably reduce CO2 and other GHGs. Cutting methane now can dampen climate feedback loops like the melting permafrost, which will further accelerate climate tipping by liberating the methane it contains. The less hot the planet is through this decisive decade, the fewer feedback loops the Earth will endure.
Roselund: What kind of progress has been made lately in terms of measuring methane emissions, either from point sources or in aggregate?
Gordon: Tracking methane as closely as it deserves has not been a high priority until now. Yet at the same time, it’s getting harder to track methane as the world globalizes. Take the oil and gas sector, for example. Gas used to be a regional fuel shipped domestically by pipelines. As gas trade expands globally, leakage increases along lengthening supply chains. To be zero-emitting, methane must be fully contained everywhere—pumping it out of the ground, gathering and boosting it through pipelines, liquefying and loading it into ocean-going tankers, re-gasifying it and pressurizing it back into pipelines, and using it in various commercial applications and residential appliances.
Instead of spanning 1,000 miles, now a typical gas molecule can traverse 7,500 miles or more. The potential to leak is intensifying. Quickly spotting and plugging point sources is critical to avoid runaway emissions in the aggregate.
Methane is a tiny molecule under high pressure. This complicates progress to keep it carefully contained. Basically, methane wants to escape. It leaks constantly from normal operations and intermittently and in large volumes due to poor maintenance and accidents.
Methane leakage also presents risks beyond climate change. In addition to causing fires and explosions, methane impacts environmental justice. While natural gas is upwards of 90% methane, it also contains carcinogens and air toxics like benzene, toluene, and xylene. So, preventing methane emissions has public health co-benefits, especially in highly industrialized areas surrounded by workers and low-income residents.
Taken together, the climate, safety, and public health imperatives to tightly manage methane merit improved emissions visibility, attribution, policy oversight, and market activation. RMI has several efforts underway. As part of the Climate TRACE coalition, we are assessing and visualizing methane and CO2 from oil and gas systems around the world.
RMI is also participating in Carbon Mapper, a public-private-non-profit consortium that will launch its first two satellites in 2023 to spot and curtail methane super emitters. Carbon Mapper is part of the growing ecosystem of remote sensing devices, including satellites, drones, flyovers, hand-held instruments, and continuous sensors, to spot and stem methane leakages. And we are a founding member of MiQ, a voluntary standard that differentiates natural gas suppliers based on their methane emissions. Progress on all of these fronts matters for the climate, and for public health too.