Researchers employing a general circulation model have forged a previously unappreciated connection between greenhouse-gas warming and ozone in the lower stratosphere. Their conclusion is tentative but worrisome — that despite reductions in the emissions of ozone-depleting chlorofluorocarbons, levels of ozone over the Arctic will continue to decline until well into the next century. These findings will however be subject to rigorous further testing by both observation and theory.
