Our understanding of ozone in the upper atmosphere seems to have progressed quite a bit. Banning ozone depleting chemicals hasn't made much of a difference:
"Our latest bulletin shows that the hole in the ozone layer over the Antarctic has beaten that of last year and is rivalling the two largest on record -- 2000 was the largest and 2003 was the second largest," said WMO spokesman Mark Oliver.And won't make a difference anytime soon:
.....Braathens reiterated recent findings showing that the seasonal depletion of ozone in the upper atmosphere was expected to continue for longer than expected despite the control measures.Ah, so it's "expected to continue for longer than expected." I see. In other words, "The good effects we promised won't happen until after we ozone-scientists retire."
"Although ozone depleting substances are on the way down slowly... we will in the next couple of decades expect to see ozone holes of the size we are seeing now," he said.