A powerful eye in the sky is helping scientists detect “super emitters” of methane, a greenhouse gas about 80 times more potent than carbon dioxide.
That observer is NASA’s Earth Surface Mineral Dust Source Investigation Instrument, or EMIT for short. EMIT has been dust chemical composition mapping in all the desert regions of the Earth since it settled on the outside of the International Space Station (ISS) in July, helping researchers understand how dust in the air affects climate.
That is the main objective of the EMIT mission. But it’s also making another, less-expected contribution to climate studies, NASA officials announced Tuesday (Oct. 25). The instrument is identifying huge plumes of heat that trap methane gas around the world – more than 50 of them already, in fact.
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“Curbing methane emissions is the key to limiting global warming. This exciting new development will not only help researchers better identify where methane leaks are coming from, but also provide insights into how they can be addressed quickly,” said NASA Administrator Bill Nelson. said in a statement (opens in a new tab).
“The International Space Station and the more than two dozen NASA satellites and instruments in space have long been invaluable in determining changes in Earth’s climate,” added Nelson. “EMIT is proving to be a critical tool in our toolbox for measuring this powerful greenhouse gases – and stop it at the source.”
EMIT is an imaging spectrometer designed to identify the chemical fingerprints of a variety of minerals on the Earth’s surface. The ability to detect methane is also something of a happy accident.
“It turns out that methane also has a spectral signature in the same wavelength range, and that’s what has allowed us to be sensitive to methane,” he said during a news conference on Tuesday afternoon.
Green and other members of the EMIT team gave some examples of the instrument’s sensitivity during Tuesday’s press conference. For example, the instrument detected a plume of methane, also known as natural gas, at least 4.8 kilometers (3 miles) long in the sky above an Iranian landfill. This newly discovered super emitter is pumping about 18,700 pounds (8,500 kilograms) of methane into the air every hour, the researchers said.
That’s a lot, but it pales in comparison to a group of 12 EMIT super-emitters detected in Turkmenistan, all associated with oil and gas infrastructure. Some of those plumes are up to 20 miles (32 km) long and, together, add about 111,000 pounds (50,400 kg) of methane to earth’s atmosphere per hour.
That’s comparable to peak rates from the Aliso Canyon leak, one of the largest methane releases in US history. (The Aliso Canyon event, which occurred at a Southern California methane storage facility, was first noticed in October 2015 and didn’t fully plug until February 2016.)
EMIT detected all of these super emitters very early, during the instrument verification phase. Therefore, it should make even greater contributions as it becomes fully operational and as scientists become more familiar with the instrument’s capabilities, team members said.
“We’re really just scratching the surface of EMIT’s potential for mapping greenhouse gases,” Andrew Thorpe, a research technologist at JPL, said during Tuesday’s news conference. “We are really excited about the potential for EMIT to reduce emissions from human activity by identifying these emission sources.”
Mike Wall is the author of “out there (opens in a new tab)(Grand Central Publishing, 2018; Illustrated by Karl Tate), a book about the search for extraterrestrial life. Follow him on Twitter @migueldwall (opens in a new tab). Follow us on Twitter @spacedot.com (opens in a new tab) or in Facebook (opens in a new tab).
