The National Aeronautics and Space Administration, Johns Hopkins University and the Netherlands Environmental Assessment Agency scientists said if the ozone-banning treaty known as the Montreal Protocol that went into effect in 1989 hadn't existed, nearly two-thirds of Earth's ozone would have disappeared by 2065. That would have caused ultraviolet radiation strong enough in mid-latitude cities such as Washington to produce sunburn in just 5 minutes and with DNA mutating UV radiation increasing more than 650 percent, with likely resulting effects on plants, animals and human cancer rates.
"Ozone science and monitoring has improved over the past two decades and we have moved to a phase where we need to be accountable," said NASA scientist Paul Newman, who led the research. "We are at the point where we have to ask: Were we right about ozone? Did the Montreal Protocol work? What kind of world was avoided by phasing out ozone-depleting substances?"
The study's co-author, Richard Stolarski, said, "The Montreal Protocol is a remarkable international agreement that should be studied by those involved with global warming and the attempts to reach international agreement on that topic."
The analysis has been published online in the journal Atmospheric Chemistry and Physics.