Oh No Zone

It's going on 20 years since the Montreal Protocol to phase out ozone-destroying chemical compounds was first drawn up. The treaty, ratified in 1989, is held up as a model of international cooperation and gives hope that future accords may be reached to deal with climate change and other global environmental threats.

This is the time of year when the ozone hole over the Antarctic approaches maximum size. In a release, NASA gives the current status report and outlook. According to NASA scientist Paul Newman, "The Antarctic ozone hole will reach sizes on the order of 8-10 million square miles nearly every year until about 2018 or so. Around 2018, things should slowly start improving, and somewhere between 2020 and 2025, we’ll be able to detect that the ozone hole is actually beginning to decrease in size. Eventually the ozone hole will go back to its normal level around 2070 or so."

Alas, the good news has been marred by unintended consequences. It seems that the hydrofluorocarbons (HFCs) that have largely replaced the ozone-destroying chlorofluorocarbons (CFCs) are, in turn, extremely potent greenhouse gases and, as such, exacerbate global warming.

Uh-oh is right.