According to a press release by the United Nations, “…ozone loss over the Arctic has reached an unprecedented level this spring owing to the continuing presence of ozone-depleting substances and extremely cold temperatures.”
As you may know, The Montreal Protocol (Protocol) was signed in 1987 and became effective in 1989. The intent of the Protocol is to eliminate stratospheric ozone depleting substances. The Protocol “regulates” approximately 100 chemicals. The most common chemical group identified as ozone depleting, are chlorofluorocarbons or CFCs. CFCs have many practical uses such as refrigeration and aerosols. The problem is these chemicals are believed to cause a thinning of the protective stratospheric ozone layer around the earth. This is commonly known as the “ozone hole.”
As an aside, an unintended consequence from the ban of certain ozone depleting chemicals resulted in the use of another class of chemicals; hydroflourocarbons (HFCs), which have global warming potentials up to 14,800 times higher than carbon dioxide, the main greenhouse gas.
Ozone depleting gases in the atmosphere have been reduced as a result of the Protocol. However, as this report and others over the past several years show, the thinning of the ozone layer has been largely unaffected and continues to fluctuate. The “repair” of the ozone, based on models and predictive tools, may take another 50 years.
The end result is the Protocol is regulatory success, participatory success, but the jury is still out on the overall success.
Here is a link to the UN Press Release: