Paul Neiman: We've replaced CFCs with hydrofluorocarvins or HFCs, which are also pretty potent greenhouse gases. The Montreal Protocol parties recognized that they had, in fact, created a problem in climate. He says there have been some things touted as fixes to the climate crisis that could actually reverse some of the progress that's been made. But it sounds like we might be on the home stretch with the ozone layer, so hopefully you're not having sleepless nights anymore.