Greenhouse gas emissions reached a record high last year with “no end in sight to the rising trend”, the World Meteorological Organization (WMO) said recently. Methane concentrations and levels of nitrous oxide also saw the highest year-on-year increase from 2021 to 2022.
To identify and measure the rising concentrations of these gases from space, US space agency Nasa is using its recently launched imaging spectrometer as a greenhouse gas detector after it proved its proficiency, surprising even its designers.
Launched in July 2022, the spectrometer, called Earth Surface Mineral Dust Source Investigation (or EMIT), was launched to map 10 key minerals on the surface of the world’s arid regions. Its mineral-related observations, which are already available to researchers and the public, will help improve understanding of how dust that gets into the atmosphere affects climate.
Initially, detecting the methane was not part of the EMIT’s primary mission. However, the imaging spectrometer, which is aboard the International Space Station, has shown that it is capable of doing that. After just three months since its launch, the spectrometer detected more than 50 methane “super-emitters” from space, SciTechDaily reported. These were in Central Asia, the Middle East, and the Southwestern United States. Super-emitters refer to infrastructure that emits methane at significantly high rates. They are usually observed in the fossil fuel, waste, or agriculture sectors.
Now, a new study, published in Science Advances, reveals that EMIT has detected more than 750 emissions sources since August 2022. These include smaller ones and ones in remote locations. Lead author, Andrew Thorpe, said that EMIT has exceeded expectations. “We were a little cautious at first about what we could do with the instrument,” Thorpe said in a Nasa press statement.
The data recorded by the spectrometer can help researchers identify and address the sources of methane emissions, operators of landfills, agriculture sites, oil and gas facilities, and other methane producers. “Tracking human-caused emissions of methane is key to limiting climate change because it offers a comparatively low-cost, rapid approach to reducing greenhouse gases,” Nasa adds in the statement. Methane is known to linger in the atmosphere for about a decade but can be about 80 times more powerful at trapping heat than carbon dioxide, which remains for centuries.
The new study reveals that EMIT, based on its first 30 days of greenhouse gas detection, can detect 60% to 85% of the methane plumes usually seen in airborne campaigns. From around 250 miles (400 kilometres) altitude on the space station, EMIT collects data over vast areas of Earth, particularly the arid regions that fall between 51.6 degrees north and south latitude, the statement explains. For instance, in September 2022, EMIT identified a cluster of emissions sources in a rarely studied region of southern Uzbekistan. In this area, the instrument detected 12 methane plumes, totalling about 49,734 pounds (approximately 22,559 kilograms) per hour.
Technology such as EMIT aims to address the current trajectory of rising greenhouse gas concentrations in the atmosphere, which has been warned to be catastrophic.