International ozone treaty stops changes in Southern Hemisphere winds

The Montreal Protocol of 1987 phased out production of ozone-destroying substances such as chlorofluorocarbons (CFCs). Beginning around 2000, concentrations of those chemicals in the stratosphere started to decline and the ozone hole began to recover. In this study, researchers have shown that around the year 2000, the circulation of the Southern Hemisphere also stopped expanding polewards -- a pause or slight reversal of the earlier trends.