Here is a dilemma: Antarctica may heat up dramatically as ozone hole repairs. It seems that the ozone hole above Antarctica has changed air flows so as to keep Antarctica colder than it would have been without the ozone hole.

Should we return to using products that use CFCs in order to keep the ozone hole above Antarctica for now in order to stop rapid temperature rise there? This does illustrate that some geo-engineering is possible even if other side-effects are undesirable.