Using Aura Microwave Limb Sounder satellite observations of stratospheric nitrous oxide (N2O), ozone, and temperature from 2005 through 2021, we calculate the atmospheric lifetime of N2O to be decreasing. Because N2O abundances in the middle tropical stratosphere, where it is
10 photochemically destroyed, increased at a faster rate than the bulk N2O in the lower atmosphere, the lifetime is becoming shorter. The cause appears to be a more vigorous stratospheric circulation, which models predict to result from climate change. If this climate-driven circulation trend continues to 2100, then anthropogenic N2O emissions will be removed 20% faster than current projections, and their impact on global warming and ozone depletion will be proportionately lessened. This finding is an
15 example of a distinct negative, but relatively minor, climate-chemistry feedback.
