Sorry, Earth, The Ozone Layer Isn’t Healing Itself After All
“Owing to global warming, there are suggestions that the tropopause has risen and will continue to rise, the troposphere has warmed, and these phenomena may have an effect on ozone concentrations in the lower stratosphere. Furthermore, greenhouse gas-induced climate change appears to be causing an increase in upwelling in the tropics, which could decrease stratospheric ozone there, according to simulations. The exact mechanism responsible for these changes has yet to be identified, but the data is clear: the “100% recovery by 2100” prediction didn’t include these results. With this new understanding, that recovery may be stalled or pushed out to extremely long timescales, and global warming may be exacerbating or even causing this trouble.”
More than 25 years ago, humanity banded together to accept the Montreal Protocol: a promise to eliminate CFCs and stop destroying the ozone layer. As aerosol use changed, things appeared to improve. Our measurements of the ozone in the upper stratosphere, particularly over human-populated areas, was increasing again, and it looked like the ozone layer was recovering. But more recently, we began measuring not only the upper stratosphere, but the ozone density in the lower stratosphere and the troposphere. What we’ve just found is shocking and disappointing: there is no net recovery of ozone in our atmosphere. The decreases in lower stratospheric ozone offset any increases in the other layers, meaning that the ozone layer isn’t recovering, after all. While scientists aren’t sure why, there’s one key ingredient that might be the unexpected culprit: global warming.
There’s more science to be done, but what we’ve learned is vital: the ozone layer won’t be repaired by 2100, and unless we figure out what’s going on, we might not be able to instill a recovery at all.