New research using NASA's Atmospheric Tomography Mission (ATom) found tropical forests are taking in less carbon dioxide than Earth system models have assumed. The study cut model uncertainty by half and revealed higher CO2 concentrations above the tropics than predicted, suggesting the tropical carbon sink is weaker than expected. If tropical forests are offsetting less of human emissions, more CO2 stays in the atmosphere and drives additional warming. The findings also complicate how scientists interpret rising CO2 at measurement stations, since it becomes harder to separate emission increases from sink weakening. The authors argue for sustained airborne monitoring programs to track these changes over time.
