Scientists from the United States, Japan and China are racing to perfect satellite technology that could one day measure greenhouse gas emissions from space, potentially transforming the winner into the world's first climate cop.
Monitoring a single country's net emissions from above could not only become an important tool to establish whether it had met its promises to slow global warming, a point of contention at climate talks in Paris, but also help emitters to pinpoint the sources of greenhouse gases more quickly and cheaply.
"The real success of a deal here fundamentally revolves around whether we can see emissions and their removals," said John-O Niles, director of the U.S.-based Carbon Institute, which studies methods of carbon dioxide measurement.