East of Hazar, Turkmenistan, a port city on the Caspian Sea, 12 plumes of methane stream westward. Some of the plumes, detected by NASA’s Earth Surface Mineral Dust Source Investigation mission, stretch more than 32 kilometers. Credit: NASA/JPL-CALTECH

Turkmenistan’s decision to sign the Global Methane Pledge, a voluntary agreement to slash methane emissions, was particularly gratifying for the people behind NASA’s Earth Surface Mineral Dust Source Investigation, known as EMIT.

Information from the NASA Jet Propulsion Laboratory’s EMIT imaging spectrometer mounted on the International Space Station and other sensors are helping Turkmenistan pinpoint the sources of leaks that made the Central Asian nation the world’s fourth highest methane emitter.

“Last weekend, Turkmenistan signed the Global Methane Pledge,” K. Dana Chadwick, EMIT mission applications lead, announced Dec. 13 at the American Geophysical Union’s annual meeting in San Francisco, prompting enthusiastic applause. “We are incredibly proud to have been able to work with them.”

Satellites are playing a growing role in identifying methane sources at a time when methane is in the spotlight. Last month at the 2023 United Nations Climate Change Conference in Dubai, known as COP28, international leaders called for speedy action to curb methane emissions and eliminate methane leaks by 2030.

“Methane is increasingly being targeted for near-term action, both because it has a very high global warming potential compared to other gases and because of opportunities for rapid, targeted and cost-effective emission reduction strategies that can complement other important climate stabilization programs like reducing carbon dioxide emissions,” said Riley Duren, CEO of Carbon Mapper, a nonprofit focused on measuring greenhouse gas emissions.

This methane plume from a landfill south of Tehran, Iran, was spotted in August 2022 using NASA’s EMIT high-resolution imaging spectrometer on the International Space Station. An interactive map shows the more than 800 point-source emitters of methane and carbon dioxide found with EMIT. Credit: NASA/JPL–CALTECH

Immediate Benefit

The Global Methane Pledge aims to cut emissions of the potent greenhouse gas 30 percent from 2020 levels by 2030. At the conclusion of the two-week climate conference in Dubai, 156 nations had signed it.

Individual countries are also imposing fees for methane emissions. In the United States, a provision of the 2022 Inflation Reduction Act requires companies that report greenhouse gas emissions to the Environmental Protection Agency to pay $900 per metric ton of methane released, beginning in 2024. The fee rises to $1,500 in 2026.

“If you can reduce methane emissions today, you will have an immediate climate benefit,” said Duren, whose also a University of Arizona research scientist. “This doesn’t solve the climate problems, but it may give us breathing room to get our arms around the carbon dioxide problem.”

A Key Lever

Steven Hamburg, Environmental Defense Fund chief scientist, said addressing climate change requires speedy action to slow the rate of warming and long-term steps to limit overall global warming.

“Methane accounts for “about 30% of the warming we’re currently experiencing,” Hamburg said Jan. 21 during a SpaceNews webinar. “Methane is the key lever for slowing the rate of warming. Carbon dioxide emissions must also be reduced because they are going to dominate the total warming. We have to do both.”

Atmospheric methane often leaks from natural gas and waste management systems.

“These engineered systems leak just like plumbing,” Duren said in a Dec. 12 talk at the San Francisco headquarters of Planet, the company building Carbon Mapper satellites. “If you can find and fix the leaks, you can get rid of a lot of methane quickly.”

EMIT imaging spectrometer prior to launch. Credit: NASA/JPL

Smokestacks have always offered the telltale sign of carbon dioxide rising into the atmosphere. Methane leaks at remote gas and oil facilities, though, often went undetected until government and commercial sensors began revealing their locations.

“People can no longer pretend methane leaks are not happening,” Robert Green, EMIT principal investigator at JPL, said at the AGU meeting. “They are not invisible anymore.”

Government satellites

Monitoring atmospheric methane is a global endeavor involving terrestrial, airborne and satellite sensors.

Japan began monitoring methane from space with the Greenhouse Gases Observing Satellite (GOSAT) launched in 2009. The original GOSAT continues to track methane emissions, and its successor — GOSAT-2, launched in 2018 — also measures atmospheric carbon monoxide.

Tropomi, an instrument on the European Space Agency-European Commission Copernicus Sentinel-5P satellite launched in 2017, provides data for daily methane maps and identifies the world’s largest emitters.

China tracks methane with Gaofen-5, launched in 2018, and Fen Yung 3G, sent aloft in 2023.

GHGSat unveiled Pulse, a free map showing average weekly methane concentrations around the world at a resolution of approximately two kilometers per pixel. Credit: GHGSat

Commercial sensors

Canada’s GHGSat began detecting methane sources in 2016 with Claire, the first commercial satellite to monitor greenhouse gas emissions. With a constellation of 12 satellites, including Vanguard, the company’s first to focus on carbon dioxide, GHGSat monitors industrial facilities and shares data with NASA, ESA, the United Nations and the oil and gas industry.

“We monitor methane emissions around the world and work closely with industry and governments to look at emissions and provide the best information possible to drive action,” Jean-Francois Gauthier, GHGSat senior vice president strategy said during the webinar.

In a sign of increasing coordination among methane detectors, GHGSat has shown it can automate detection and monitoring of methane super-emitters by combining data from its own satellite fleet with observations from Tropomi, ESA’s Sentinel-2 and Prisma, an Italian Space Agency hyperspectral technology demonstrator launched in 2019. (Super-emitters are defined as sources that release at least 100 kilograms of methane per hour, according to an Environmental Protection Agency rule released in December.)

In parallel, Maxar developed a proprietary algorithm to map methane plumes at a resolution of 3.7 meters per pixel after ingesting data from WorldView-3’s shortwave infrared sensor and other sensors.

“Sentinel detects emissions over larger areas and at lower resolution,” Tomi Maxted, Maxar communications director, said by email. “This capability is complementary to ours and can be used to tip and cue higher-resolution sensors such as the one onboard WorldView-3.”

Artist’s render of MethaneSAT Credit: Ball Aerospace Corp.

Instruments on deck

Additional methane monitoring from space is imminent.

The nonprofit Environmental Defense Fund’s MethaneSAT, set to launch in 2024, is designed to show regional-scale emissions and identify sources large enough to produce more than 500 kilograms of methane per hour.

The satellite and whole mission were “explicitly designed to provide actionable data and to map the globe and to understand the quantity of emissions, the location of those emissions and track them over time,” Hamburg said.

MethaneSAT is funded in part by the New Zealand government. Ball Aerospace is building MethaneSAT’s instrument, an advanced spectrometer to fly on a Blue Canyon Technologies spacecraft. Rocket Lab is responsible for MethaneSAT’s mission control center in New Zealand.

An artist rendering of GHGSat satellites. Credit: GHGSAT

Carbon Mapper

Another public-private partnership backed by the State of California and the Jet Propulsion Laboratory is behind the Carbon Mapper constellation of hyperspectral satellites to pinpoint, quantify and track point sources of methane and carbon dioxide.

Carbon Mapper partners, including the University of Arizona, Arizona State University, the High Tide Foundation and the non-profit RMI, are supporting a campaign to fly hyperspectral sensors developed at JPL on Planet’s new Tanager satellites. The first two satellites launching in 2024 will provide free data on methane and carbon dioxide emissions.

“Our goal is to build a constellation that will eventually give us daily or sub-daily operational monitoring of greenhouse gases around the world,” Duren said.

Government constellations are growing as well. Japan plans to extend its GOSAT series in 2024 with the launch of the GOSAT Greenhouse gases and Water cycle spacecraft. An infrared spectrometer on GOSAT-GW will measure monthly mean concentrations of greenhouse gases, calculate national anthropogenic greenhouse gas inventories and large emission sources like power plants.

Planet is developing Carbon Mapper satellites. The satellites, which are approximately the size of Planet SkySats. Credit: Planet

EMIT extension

EMIT, meanwhile, could be approved for an extended mission. The sensor, designed primarily to reveal how minerals in airborne dust heat and cool Earth’s atmosphere, was expected to leave its International Space Station perch in late 2023.

Instead, NASA is considering extending the EMIT mission and expanding its observations beyond Earth’s arid regions in part because of its contribution to greenhouse-gas monitoring.

Prior to EMIT’s installation on ISS in 2022, scientists knew the imaging spectrometer offered the promise of exposing greenhouse gas sources.

“But it’s turned out better than I expected,” Green said. “It turns out to be an excellent source for mapping large methane and carbon dioxide sources.”

This article first appeared in the January 2024 issue of SpaceNews magazine. Content was added from the Jan. 21 SpaceNews webinar: Not Invisible Anymore: How Satellite Monitor Atmospheric Methane.

Debra Werner is a correspondent for SpaceNews based in San Francisco. Debra earned a bachelor’s degree in communications from the University of California, Berkeley, and a master’s degree in Journalism from Northwestern University. She...