Written by Neil Auwarter Did you know methane is a far more potent greenhouse gas than carbon dioxide? But methane has an Achilles heel: it is a sprinter, not a marathoner. Read on to understand how methane presents our best opportunity to fight climate change in the near-term.
A Primer on Methane as a Greenhouse Gas
Methane (CH4) is a hydrocarbon emitted as gas by a variety of human and natural sources. Primary human-caused sources include agriculture and leaks from oil and gas extraction and transmission. After carbon dioxide (CO2), methane is the next most prevalent GHG globally. However, reducing methane emissions would actually have a more beneficial near-term effect on climate than reducing an equal amount of CO2 emissions.
A bit of chemistry and physics explains how methane punches above its weight as a GHG: Methane is an extremely potent GHG, trapping 100 times more heat than CO2 when emitted. Even after 20 years methane will have trapped about 80 times more heat than an equal amount of CO2.1 But methane loses its potency through oxidation in about 12 years. CO2, while much less potent as a GHG, lasts in the atmosphere for hundreds, even thousands, of years. As the MIT Climate Portal puts it, “methane does its damage quickly but soon fades away, while CO2 traps a smaller amount of heat consistently, decade after decade.”2
The net result is that while methane accounts for only about 16% of human-caused GHG emissions by weight, it accounts for about 30% of climate warming.3 More importantly for the future, an immediate reduction in methane emissions would yield vastly greater near-term climate remediation than an immediate reduction of an equal amount CO2. To illustrate, if humans were to immediately cease emitting all CO2, the climate impact would be beneficial but very slight over the next decade–because the vast bulk of CO2-caused climate warming is due to gas emitted tens and even hundreds of years ago, still lingering in the atmosphere. But if humans were to immediately cease emitting all methane, then after 12 years all anthropogenic methane would be gone from the atmosphere, and global warming would be quickly reduced by about 30%.4
How much methane reduction is realistic in the near term? According to one estimate, methane emissions could be reduced by 45% in the next ten years, averting 0.3°C (0.5°F) in global warming by 2045. This rapid improvement would put the planet on track to meet the goal set by the Paris Agreement of limiting climate warming to 1.5°C (2.7°F), relative to pre-industrial levels.5 Rob Jackson, an Earth Systems scientist at Stanford University, put it this way: “Methane is the strongest lever we have to slow global warming over the next few decades.”6
A Partial Setback in the Ninth Circuit:
California Restaurant Association v. City of Berkeley
Methane is the primary component of natural gas, and significant amounts leak unburned from gas appliances. One recent study concluded the methane leaked from the 40 million gas stoves in U.S. homes has a climate impact equivalent to the CO2 emissions from 500,000 gasoline-powered cars.7 Further, the leaking of unburned methane is only part of the picture because natural gas that successfully reaches the burner is then emitted as CO2.
With the goal of reducing GHG emissions from gas-burning stoves and furnaces, some cities, including Berkeley, CA have enacted local building codes prohibiting gas hook-ups to new buildings. Such local measures are aimed at hastening the conversion to greener electric appliances. However, in a recent court case the U.S. Court of Appeals for the Ninth Circuit struck down the Berkeley gas hook-up ban. In the Berkeley case, the California Restaurant Association, a group representing restaurateurs and chefs, sued the city, arguing its gas ban on new construction violated the federal Energy Policy & Conservation Act (EPCA). The EPCA sets nation-wide energy efficiency standards governing the amount of natural gas that may be used by gas appliances, including stoves. Further, the EPCA includes a preemption provision stating that, with certain exceptions, no state or local law may impose its own efficiency standard on appliances covered by the EPCA.8 (CRA v. Berkeley, amended decision, p. 14)
Berkeley argued its law was not a competing energy efficiency standard, but rather an outright ban on gas to new buildings; as such, Berkeley, argued, its law was not preempted by the EPCA. A three-judge panel of the Ninth Circuit disagreed, reasoning that an outright ban on gas was in effect an efficiency standard reducing gas use to zero in new buildings. Accordingly, the court invalidated the Berkeley gas ban.9 (CRA v. Berkeley, amended decision, pp. 15-17)
Berkeley asked the court to rehear the case. The court denied this request but issued an amended decision with language offering a roadmap as to how states and cities might reduce natural gas use without running afoul of the EPCA. Specifically, the court noted that another federal statute, the Natural Gas Act, gives state and local governments the authority to regulate “the local distribution of natural gas.” The court further noted that the Berkeley law did not regulate where gas could be distributed, but rather prevented new buildings from connecting to existing gas meters to which gas had already been distributed.10 (CRA v. Berkeley, amended decision, pp. 8, 23-26) Painting its roadmap even clearer, the court added:
“Our holding here has nothing to say about a State or local government regulation of a utility’s distribution of natural gas to premises where [appliances governed by the EPCA] might be used. We only decide that EPCA’s preemptive scope applies to building codes that regulate the gas usage of [such] appliances where gas is otherwise available.”11 (CRA v. Berkeley, amended decision, pp. 18-19)
Opening the Door Left Ajar by CRA v. Berkeley
The above language in the amended Berkeley decision appears to suggest the court would view the EPCA as permitting a city or state to bar the expansion of natural gas delivery to new locations not already served by existing gas meters. This offers cities and states an enormous potential opportunity to mitigate natural gas expansion since many sites for new development are not reached by existing gas lines.
Notably, it is likely CRA v. Berkeley would also allow states and cities to impose limits on how much methane may be leaked from appliances while not in use. This is significant because the Stanford study found that 75% of the methane leaked at stove locations occurs while the stoves are off.12 This gas presumably leaks from wall hook-ups or within stoves. Because this leaked gas is not “used” by the appliance, local regulations aimed at limiting such emissions would likely survive CRA v. Berkeley. Further, it is likely the EPCA would not preempt laws limiting the permissible level of GHG emissions in a building. This approach, exemplified by New York City’s building code, places no limit on the efficiency or emissions of a particular appliance, but instead limits total emission levels within a building.13
Finally, a note on the likelihood courts outside the Ninth Circuit will agree with CRA v. Berkeley. The Ninth Circuit is considered a moderately progressive court on environmental issues,14 (Pitt Law Review, p. 77) and so this decision is probably not an outlier. It is likely at least some federal courts in other circuits will agree with CRA v. Berkeley, and that the U.S. Supreme Court would do the same if it were to consider the issue. Accordingly, it would be prudent for concerned local governments anywhere in the U.S. to explore methane emission regulations that would comply with CRA v. Berkeley.
A Major Advance in Methane Detection:
The Launch of MethaneSAT
In March 2024 one of Elon Musk’s SpaceX Falcon 9 rockets blasted off from Vandenberg Space Force Base near Santa Barbara, California. The rocket carried dozens of satellites, including MethaneSAT. Developed in a project led by the Environmental Defense Fund, MethaneSAT will use an infrared spectrometer to detect the unique light signature of the methane molecule. The focus of MethaneSAT will be to detect large methane leaks from oil and gas producers.15
The developers of MethaneSAT chose to target oil and gas production rather than other major emitters of methane, such as agriculture, because oil and gas is an industry with a small number of producers with means to significantly reduce emissions. With the oil and gas industry, “[t]he ability to remediate is much greater and it’s cost-effective,” explained EDF chief scientist Steven Hamburg.16 Satellite detection of methane has a distinct advantage over physical site inspections. As Stanford University Energy Science professor Adam Brandt put it, “The beauty of having MethaneSAT [is] we don’t have to ask [producers] permission nicely to go on site and make measurements. . ..”17
Further, MethaneSAT takes a step beyond previously launched methane detecting satellites because its imaging is more accurate and covers “80 percent of oil and gas companies’ global production.”18
The launch of MethaneSAT is well-timed because in 2023 the U.S. Environmental Protection Agency enacted a new rule requiring oil and gas producers to monitor and fix methane leaks. The data collected by MethaneSAT will be made public and available to government regulators to help enforce the EPA’s new rule.19
Final Note: Weighing the Advance by MethaneSAT
Against the Setback in CRA v. Berkeley
Annual methane emissions from gas stoves in U.S. homes are estimated at 28,000 tons.20 By comparison, an estimated 8 to 13 million tons of methane is leaked annually by the U.S. oil and gas industry.21 The relatively small number of U.S. oil and gas producers, combined with the EPA mitigation rule, and powered by the data from MethaneSAT, creates opportunities for substantially reducing methane emissions from the supply chain. And as noted previously, CRA v. Berkeley leaves the door open for cities to continue to find innovative ways to reduce demand for gas by transitioning homes and businesses to electric appliances. On balance, it is fair to say that CRA v. Berkeley and MethaneSAT are not so much “one step back, one step forward,” as “one step back, ten steps forward.”
Neil Auwarter is a contributing member of the Grassroots Network Climate Emergency Mobilization team. If you have a suggestion for a future blog topic or are interested in joining the team, please reach out to us at climateemergency[at]sfbaysc[dot]org.