News - Ozone layer not only not recovering, but possibly expanding, study says

The recovery of the ozone layer—which sits kilometers above the Earth and protects the planet from ultraviolet radiation—has been celebrated as one of the world's greatest environmental achievements. But in a new study, some scientists claim it may not be recovering at all, and that the hole may even be expanding, CNN reported. In 1987, several countries agreed to ban or phase down the use of more than 100 ozone-depleting chemicals that had caused a "hole" in the layer above Antarctica. The depletion is mainly attributed to the use of chlorofluorocarbons, or CFCs, which were common in aerosol sprays, solvents and refrigerants. In a paper, published by Nature Communications, they found that ozone levels have reduced by 26 percent since 2004 at the core of the hole in the Antarctic springtime. "This means that the hole has not only remained large in area, but it has also become deeper [i.e., has less ozone] throughout most of Antarctic spring," said Hannah Kessenich, a PhD Student at the University of Otago and lead author of the study. To reach that conclusion, the scientists analyzed the ozone layer's behavior from September to November using a satellite instrument. They used historical data to compare that behavior and changing ozone levels, and to measure signs of ozone recovery. They then sought to identify what was driving these changes. They found that the depletion of ozone and deepening of the hole were a result of changes in the Antarctic polar vortex, a vast swirl of low pressure and very cold air, high above the South Pole. The study's authors didn't go further to explore what was causing those changes, but they acknowledged that many factors could also contribute to ozone depletion, including planet-warming pollution; tiny, airborne particles that are emitted from wildfires and volcanoes; and changes in the solar cycle.