Cutting Methane Emissions Quickly Could Slow Climate Warming Rate by 30%

Tuesday, Apr 27, 2021
by Environmental Defense Fund (adapted)
New analysis highlights dramatic benefit of swift action on a potent greenhouse gas, underscores missed opportunity if solutions are slow or delayed

A recently published paper in the journal Environmental Research Letters shows that a rapid, full-scale effort to reduce methane emissions from the oil and gas industry, large-scale agriculture and other human sources could slow the worldwide rate of warming by as much as 30%.

The lead author of the paper is Dr. Ilissa B. Ocko, who received her PhD from Princeton University's Atmospheric and Oceanic Studies Department and is now a senior climate scientist and Barbra Streisand Chair of Environmental Studies at Environmental Defense Fund. Co-authors include three Princeton faculty, including Michael Oppenheimer, Denise Mauzerall, and Stephen Pacala.

The results highlight the critical role of methane in any climate strategy, even as we decarbonize our energy systems. By reducing emissions of methane — which has more than 80 times the warming power of CO2 for the first 20 years it’s in the atmosphere — we can hit the brakes on the increasingly rapid warming responsible for stronger storms, hotter fire seasons and rapidly melting Arctic sea ice.

“Acting now and moving quickly to cut methane emissions is essential. Even modest delay would mean missing out on significant climate benefits. That’s an opportunity we won’t get back,” said Ocko. “To realize these climate benefits, decision makers need to address methane directly and not assume the problem will resolve itself as a result of policies to reduce CO2.”

Earlier this month, the U.S. National Oceanic and Atmospheric Administration reported that current methane levels in the atmosphere are the highest on record. The paper estimates that fully deploying known solutions in the six sectors responsible for the lion’s share of emissions could cut the amount of methane from human sources in half by 2030, avoiding a 0.25 degree Celsius (0.5 degree Fahrenheit) of additional global-mean warming by midcentury, and more than 0.5 C (1 F) by 2100.

A half-degree C would make a critical difference in a world trying to keep warming below 2 C. It could mean 10 million fewer people at risk from sea level rise; half the number of people stressed for water and half the number of plant and animal species losing crucial habitat.

Cheapest emission cuts are in oil and gas

The new paper encompasses a broad suite of solutions which exist today that, if implemented over the next decade, could cut projected 2030 methane emissions in half, with half of that reduction achievable at no net cost. Around 80% of no-cost actions come from the oil and gas industry. In each of the scenarios analyzed; nearly a third of that would come from top oil and gas producers meeting their agreed upon targets to reduce upstream leakage.

Compared with the fast-action scenario, a go-slow approach that starts now but stretches out full adoption from 2030 to 2050 would mean a 5% increase in the average worldwide warming rate and an extra 0.1 C by 2050. Likewise, a delayed-start strategy that squeezes reductions into a 10-year window starting in 2040 — perhaps in a rush to achieve midcentury net-zero emission goals — would result in a 20% faster warming rate and an additional 0.2 C by 2050 compared with a fast-action plan that starts now.

Without action, methane emissions from human activities are expected to keep rising for the rest of the century, increasing 70% or more by 2100, for a worldwide total exceeding 600 million metric tonnes per year. Three-quarters of those emissions are projected to come from livestock, oil and gas, and landfills, each in roughly equal measure.

Policy math masks role of methane

Despite growing concern, important scientific and policy conversations still tend to deemphasize the role of methane in driving warming. That’s because metrics used by the United Nations Framework Convention on Climate Change and others are tied to the 100-year warming potential of greenhouse gases.

“The amount of warming over the long term is important, but so is the speed of warming,” Ocko said. “By overlooking the near-term warming from methane, we’re missing an opportunity to make a real difference right now, in our lifetime. This truly is the methane moment.”

Authors of the new paper say public policy and industry measures aimed specifically at methane will be faster and more effective than counting on reductions to occur as a secondary effect of reduced fossil fuel use. They note that under leading decarbonization scenarios, methane emissions will not be significantly reduced before midcentury.

Monitoring and measurement

Growing focus on reducing emissions comes at the same time as a revolution in methane sensing and measurement technologies. These solutions range from handheld detectors to sensors carried on aircraft and unmanned drones. Increasingly, researchers and policymakers are looking to satellite detection to identify and measure emissions.

Among these is MethaneSAT, developed by an EDF subsidiary. The satellite will continuously detect, map and quantify emissions worldwide, measuring changes in concentrations as low as 2 parts per billion, giving it the ability to track changes in emission rates against commitments by countries as well as companies. Now in advanced manufacturing stages, MethaneSAT is on track for launch readiness in the fall of 2022.

 

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