New analyses of global air measurements show that five years after an unexpected spike in emissions of the banned ozone-depleting chemical chlorofluorocarbon CFC-11, they dropped sharply between 2018 and 2019.
A NOAA study published in the journal Nature demonstrates a profound effect of the Montreal Protocol: as levels of ozone-depleting chemicals controlled by the intenational treaty declined, a poleward shift of summertime circulation patterns in the Southern Hemisphere halted.
Emissions of one of the chemicals most responsible for the Antarctic ozone hole are on the rise, despite an international treaty that required an end to its production in 2010, a new NOAA study shows.