New Delhi: The first ever global maps of human emissions of carbon dioxide have been created by scientists solely using satellite observations of the greenhouse gas.
Based on data from NASA's Orbiting Carbon Observatory-2 (OCO-2) satellite, scientists from the Finnish Meteorological Institute, Helsinki, produced three main maps that generated with a new data-processing technique and agree well with inventories of known carbon dioxide emissions.
As per NASA, no satellite before OCO-2 was capable of measuring carbon dioxide in fine enough detail to allow researchers to create maps of human emissions from the satellite data alone. Instead, earlier maps also incorporated estimates from economic data and modeling results.
The maps, each centered on one of Earth's highest-emitting regions - the eastern United States, central Europe and East Asia - show widespread carbon dioxide across major urban areas and smaller pockets of high emissions.
(Human carbon dioxide emissions over Europe, the Middle East and northern Africa- Credits: FMI)
"OCO-2 can even detect smaller, isolated emitting areas like individual cities," said research scientist Janne Hakkarainen, who led the study. "It's a very powerful tool that gives new insight."
To be sure their method was correct, scientists compared the results with measurements of nitrogen dioxide - another gas emitted from fossil fuel combustion - from the Ozone Monitoring Instrument (OMI), a Dutch-Finnish instrument on NASA's Aura satellite.
OMI and OCO-2 are both in the A-Train satellite constellation, so the two measurements cover the same area of Earth and are separated in time by only 15 minutes.
The two measurements correlated well, giving the researchers confidence that their new technique produced reliable results.
Human emissions of carbon dioxide have grown at a significant rate since the Industrial Revolution, and the greenhouse gas lingers in the atmosphere for a century or more.
The results appear in a paper titled published November 1 in the journal Geophysical Research Letters.