Satellites That Can Pinpoint Methane and Carbon Dioxide Leaks

The world’s first space-based system to help identify specific sources of greenhouse gas emissions is now circling the Earth.

The main unit in the network, an orbiter called the Tropospheric Monitoring Instrument (Tropomi), is a package of state-of-the-art sensors launched by the European Space Agency (ESA) in October. By December, it had begun to map the plumes of methane, carbon dioxide, nitrogen oxides, carbon monoxide and various aerosols over industrial facilities and cities as it passed over Europe, Asia, Africa and South America.

Built to eventually map emissions planetwide every 24 hours and to show pollutants in higher resolution than ever before, Tropomi’s sharper images drew raves from its sponsors. Josef Aschbacher, director of ESA’s Earth observation programs, called it a “milestone for Europe“ and noted that it will be “valuable for helping to put appropriate mitigation policies in place.”

It may also prove to be a high-water mark for North America. Tropomi has been exchanging information with the owners of a second satellite, called Claire. It was launched in 2016 by GHGSat Inc., a Montreal-based company, to find leaking gases at sites like wellheads. Stephane Germain, the CEO, says that Claire’s sensors are miniaturized to fit into a package the size of a microwave oven. The orbiter, a silver rectangular box, has been using Tropomi’s information to home in on industrial facilities, such as oil and gas operations, to see if they have sprung methane leaks.

Tropomi can get its resolution down to about a square mile on Earth—a area that lets it see the emissions from a specific city. Germain saw a business opportunity there for Claire—named after a newborn child of one of his company’s engineers. Working with the Canadian Space Agency, GHGSat spent three years designing a satellite whose lightweight imaging spectrometer can focus on an area as small as 164 square feet. That should allow Claire to pinpoint the exact source of the leaking methane so the company can fix it.

Under a cap-and-trade system to reduce emissions, like the one in California and Quebec, the cost of methane leaks can add up. Refineries, pipelines and remote fields of oil and gas wellheads can be hard to monitor, but an orbiting satellite traveling over 4 miles per second can measure a facility’s emissions more cheaply, more accurately and more often.

By now, GHGSat says it has measured emissions from over 2,000 sites across the world.

“Primarily we want to serve industrial operations,” Germain explained in an interview, but his company is also interested in comparing measurement techniques with government regulators. He hopes one day the same emissions data will be available to everybody to inform policymaking.


Ultimately, big industrial emitters will need “tiered systems” of sensors, Germain thinks. His company is preparing to launch two more satellites and is developing sensor packages that can be carried by aircraft, along with ground-based emissions sensors to monitor large industrial complexes.

Those efforts have attracted a potential U.S. competitor, Bluefield Technologies of Palo Alto, Calif. Its CEO, Yotam Ariel, has formed a team of scientists and engineers who are designing a satellite the size of a backpack to spot the distinctive patterns of sunlight that is reflected from small emissions of methane on Earth. Bluefield is one of many new companies taking advantage of new “CubeSats,” or tiny satellites that can make inexpensive measurements from space (Climatewire, Jan. 29).

Bluefield is building its own list of clients and hopes to launch two satellites over the next two years. They will be miniaturized versions of what NASA has used for over 30 years. “It is not in space yet, but we have no doubts that the physics works,” said Ariel.

Ultimately, Ariel predicts that the government will outsource satellite monitoring of greenhouse gas emissions to private companies. “We’re providing a cost-effective way to do this globally and to have less of a debate on the data,” he said. He expects it will take five to seven years for a private satellite industry to fully form, but it would save businesses money.

He hopes to sell satellite data to investors in oil and gas companies, such as hedge funds, and to government agencies, environmental groups and insurance companies that might want to monitor a company’s progress in reducing emissions.

Ariel thinks landfills, cattle feeding operations, power plants and other producers of methane could be clients, too. “They [the client companies] have a new way to keep an eye on their infrastructure,” he said. If there is a problem, such as a methane leak, “it rings a bell and they can send someone out to fix that.”


There may be a lot of bells ringing. The system now is a haphazard, on-the-ground monitoring network used to track greenhouse gases. In some parts of the world, it may be politically impossible. Yet the stakes are growing. In November, the World Bank announced that the value of global carbon pricing initiatives, such as California’s cap-and-trade system, is now $52 billion and growing by 7 percent each year.

This year, China may unveil its own emissions trading system, which could be the largest carbon pricing initiative in the world. But how it may develop and how it might be verified remain to be seen. Under California’s carbon system, a company is assigned a “cap” or a limit to its greenhouse gas emissions. Each metric ton of carbon must be covered by a permit. If a company reduces its emissions below the cap, it can sell excess permits for a profit. If it can’t or if it experiences, for example, long-term methane leaks, it may have to buy more permits and pay whatever price the market demands.

“The days are coming when we will have satellites in the sky that can monitor any facility on this planet,” said Rob Jackson, who heads Stanford University’s Earth system science department. “I’m quite excited about that. The environmental community will be able to watchdog any facility on Earth. I think everyone will benefit.”

Eric Kort, an atmospheric scientist at the University of Michigan, said that “the scientific community is quite excited that the Tropomi information will be useful,” but he added that GHGSat has not released enough public information to convince him that Claire, its smaller, more precisely focused satellite, works.

“I hope that they get there, because I think it will be interesting. Tropomi has opened a new kind of window on the world,” Kort said. He noted that in January, NASA announced that it hopes to enlarge its data gathering on Earth’s emissions in the early 2020s, by launching a satellite it calls the Geostationary Carbon Observatory, or “GeoCarb.”

GeoCarb will be placed in a geostationary orbit that will allow it to travel at the same speed as the Earth’s rotation, giving it what NASA calls “wall to wall” focus on North and South America. That would allow it to make as many as 10 million daily observations. It will be the first U.S. satellite to measure methane plumes near Earth’s surface.

“Methane leakage from natural gas production costs U.S. industry $5 billion to $10 billion a year,” NASA noted, not quantifying the additional costs of artificially heating up the Earth’s atmosphere. According to the space agency, methane emissions are increasing annually. Most of it comes from fossil fuel production. A smaller increase comes from agricultural production, like rice farming. The third source—forest fires—has recently been decreasing, according to a new NASA study.

Steven Hamburg, chief scientist for the Environmental Defense Fund, has spent years trying to find ways to quantify and reduce man-made methane emissions. He agrees that we’re rapidly moving into a new, more robust world of verifying emissions. Traditionally, the United States and other countries have used satellites to measure emissions in a general way, to be used in global climate models.

With Tropomi, which was primarily developed by the Netherlands Institute for Space Research, Hamburg sees a new effort to map problematic emissions on Earth. That could help policymakers develop mitigation policies.

Business-driven ventures like GHGSat’s Claire satellite can give companies an accurate picture of their emissions—while also verifying their reductions. “We need both, and we’re seeing an emergence of technologies to do that, but we shouldn’t conflate them,” Hamburg said. “Together, they create the revolution.”

For him, the revolution will produce a new data set that’s seen and measured by multiple sources. It has to be trustworthy.

Hamburg sometimes imagines a new role for himself when and if the revolutionary moment arrives. “I’d like to walk up and say: ‘Well, that’s exciting, and now I’d like to see your data.’”