Every September, the sun begins to rise over the horizon at the South Pole. Sparked by that sunlight, a season of ozone depletion begins. NOAA and CIRES researchers in the Global Monitoring Division of ESRL are critical in the international effort to understand the South Pole’s seasonal “ozone hole,” and to anticipate its future. In the South Pole Ozone blog, they and their colleagues will blog about this depletion season, as the “hole” develops and later, as ozone builds back up.