Satellites Could Track if Countries Keep Their Carbon Pledges

The 2015 Paris Agreement to limit global climate change requires that nations measure and report their progress towards reducing their emissions. They submit greenhouse gas inventories every year, which include details about emission sources and sinks. These are then reviewed by technical specialists.

Accounting is designed to ensure transparency and trust. However, it can take time and the numbers may not be exact.

What if carbon dioxide emissions were reported more quickly and accurately? This could be very useful for the world as it seeks to limit global warming.

Climate Trace, a new project that Al Gore, former Vice President, described Wednesday at an event in conjunction with the COP26 climate summit, in Glasgow, uses artificial Intelligence and machine learning to analyze satellite imagery, sensor data, and produce what it claims are accurate emissions estimates in close-real time.

NASA researchers and their colleagues reported Wednesday that they had reached a milestone in achieving a different goal: measuring actual carbon dioxide concentrations in the atmosphere, as countries take steps towards reducing their emissions.

Researchers claimed that they were able detect small reductions of atmospheric CO2 concentrations over the United States and other areas due to coronavirus lockdowns early 2020 by plugging satellite CO2 measurements into an Earth-systems modeling.

Some estimates suggest that the lockdowns caused a drop in economic activity. emissions reductions of 10 percentDespite emissions having rebounded since then, it is possible to reduce CO2 emissions by as much as 50%. Although the reductions may seem substantial, they resulted only in a very slight change in the atmospheric CO2 concentration, which currently exceeds 409 parts per million.

The researchers were able find a drop of around 0.3 parts per thousand during lockdown periods.

“We believe that this is a milestone,” said Brad Weir, a research scientist at NASA’s Goddard Space Flight Center and the lead author of a paper describing the work published in the journal Science Advances.

The satellite, Orbiting Carbon Observatory-2, wasn’t designed to measure changes in human-caused CO2 emissions. Rather, it was meant to see how large-scale natural climate patterns like El Niño and La Niña affect CO2 concentration. The satellite measures CO2 in the column of air between its position and the Earth’s surface, and can detect additional or reduced levels of the gas before it becomes uniformly mixed in the atmosphere.

“We were fortunate in that early 2020 didn’t have a strong El Niño effect,” Dr. Weir said, noting that a stronger El Niño signal would have masked the human-caused one.

In the coming years, several additional CO2-measuring satellites will be launched. “As we have better and better observing capabilities, we believe that monitoring of emissions through space-based observations is feasible,” Dr. Weir said.

Johannes Friedrich, a senior associate with the research organization World Resources Institute, who studies emissions accounting, stated that current measurements, especially of fossil fuel emissions, are reasonably accurate. Measurements are based upon reporting human activities, such as the operation of a particular coal-fired power station. Calculating the emissions from the coal that has been burned is simple and straightforward. “We know pretty much where emissions come from, and most countries record them,” Mr. Friedrich said.

There are greater uncertainties in the emissions from agriculture and deforestation. For example, estimates of greenhouse gas emissions from cattle are only estimates. Emissions from deforestation can vary depending on the extent and extent of clearing, as well as other factors.

Mr. Friedrich, who was not part of the study, said that he believed satellite-based measurements could possibly work in future. “At this time it still has pretty big challenges,” he said.

“You would need very regular measurements, at very good resolution, and very good coverage of the whole United States, for example,” he said. “And that’s still very difficult.”