Plants and soils constantly exchange carbon dioxide with the atmosphere, and extreme climate events can disrupt this exchange dramatically. The 2003 European summer drought, for example, released as much carbon as the continent's ecosystems had stored over the previous four years. A new study in AGU Advances asks how well such events can be spotted from space.
The researchers prescribed a known carbon flux, simulated what NASA's Orbiting Carbon Observatory-2 (OCO-2) satellite and ground stations would observe, and then used an inverse model to see how well the extremes could be recovered. They found that OCO-2 detects many more extremes than ground stations alone, but under realistic conditions it identifies only about 16% of extreme locations—and about half even in an idealized, error-free case. The inferred magnitudes of these events are also consistently underestimated.
Detection is better for large and long-lasting events and for hot and dry extremes, while cold and wet events are harder to detect because clouds often limit satellite observations. The results highlight both the value and the current limitations of satellite carbon monitoring, and they point to the importance of future missions with wider coverage for understanding how climate extremes affect Earth's carbon cycle.