The shocking thing about this year's quite low readings is that it comes as the CFCs are diminishing at an ever rapid rate.
If the Cl released from these agents is indeed catalytic, then nothing we now do will stop the inevitable decline.
The very first molecule released back in 1939 may be the one now responsible for our concern; wouldn't that just bite your butt!?
But there's a reservoir effect; the Cl in the stratosphere will remain there for some time, and the CFCs in the stratosphere will keep breaking down to provide more Cl. So the recovery will take time. (Where have I heard THAT line before? Nevermind...)
If the Cl released from these agents is indeed catalytic, then nothing we now do will stop the inevitable decline.
It's only catalytic on the polar ice cloud particles. (Fortunately.) And the Cl concentration will decrease over time, so the CFC phaseout will have an effect eventually.