Eyes in the sky capture carbon, other climate culprits

KATOWICE, POLAND >> A growing fleet of satellites is monitoring man-made greenhouse gas emissions from space, spurred by the need to track down major sources of climate changing gases such as methane and carbon dioxide.

While scientists and policy-makers agree that getting a firm grasp on the origins of emissions is key to tackling global warming, there is great political sensitivity surrounding the issue.

In 2009, President Barack Obama suggested during the U.N. climate talks in Copenhagen that the United States might use satellites to monitor other countries’ emissions.

Obama’s call for sharing such information “so that people can see who’s serious and who’s not” annoyed China and other countries worried about outside monitoring of their emission figures.

Experts say precise country-specific emissions accounting from space remains a long way off.

But as negotiators at this month’s climate summit in Katowice, Poland, puzzle over how to ensure countries provide accurate emissions data, a host of international agencies and private companies are once again touting space-based monitoring as an aid, if not a replacement, to self-reported figures.

So-called emissions inventories are key to implementing the 2015 Paris climate accord, but until now there’s been no international standard for them, let alone independent oversight.

Each country reports data, often years-old estimates, which are used to determine whether they’re doing enough to cut emissions. According to a recent report by the Intergovernmental Panel on Climate Change, emissions of the most abundant greenhouse gas, carbon dioxide, would need to be reduced to a level the planet can absorb — known as net zero — by 2050 to keep global warming at 1.5 degrees Celsius, as envisaged in the Paris agreement.

“It is very important to have precise information about emissions,” said Oksana Tarasova, who heads the atmospheric environment research division at the World Meteorological Organization. “We have no time to waste.”

Space-based observations allow scientists to capture the big picture, Tarasova said.

But, she added, “It’s like a Russian doll. You start from the global observation, then you go down to regional observation and to local observation.”

Half a world away, Mike Gunson and his colleagues at NASA’s Jet Propulsion Laboratory in Pasadena, California, have been operating NASA’s OCO-2 satellite since its launch in 2014. This “eye in the sky” is designed to observe carbon dioxide.

“How much fossil fuel we are willing to burn and how much carbon dioxide are we willing to put into the atmosphere is a first-order question for future climate projections,” said Gunson. “The second big question (is) how much does the terrestrial ecosystem, how much does the ocean absorb ... It’s far from settled.”

The effort to inventory the world’s greenhouse gas emissions has taken on an added urgency amid concerns that some gases may not yet be apparent.

Greet Maenhout, a scientist at the European Commission’s Joint Research Center in Ispra, Italy, said it was only recently discovered that coal mines leak carbon dioxide. “This has been seen from space by flying over it,” said Maenhout.

The Commission has funded several satellites to monitor whether European Union member states are meeting their commitment to reduce greenhouse gases by 2030 by 40 percent compared to 1990 levels.

While satellites on their own can’t provide accurate emissions figures from afar, their advantage lies in their consistency, said Claus Zehner, manager of the European Space Agency’s Sentinel-5P mission.