While global warming and climate change in general remain high on the scientific and political agendas, one of the more stubborn environmental problems of the last half century, the emergence of "holes" in the stratospheric ozone layer seems, at last, to be in reverse. The enforcement of 1987's Montreal Protocol, which was to ban the use and release of ozone-eating pollutants, seems to have had some impact, after all. However, according to NASA scientists, for the last 9 years, worldwide ozone has remained roughly constant, halting the decline first noticed in the 1980s. The hole above Antarctica remains a gaping maw, but the holes elsewhere in our atmosphere seem to be healing. Whether or not this is due to Montreal cannot be said with certainty because the ozone layer can also be affected by the weather, volcanic activity, and sunspots.