Last September was held the International Day for the Preservation of the Ozone Layer. This year was a special one, as it was the 35th anniversary of the Vienna Convention that gave rise, two years later, to the Montreal Protocol on Substances that Deplete the Ozone Layer. This protocol laid the foundations for the recovery of the ozone layer and established the control, among others, of chlorofluorocarbon compounds (CFCs), substances widely used in industry as part of refrigerators, air conditioners or aerosol propellants. Thanks to the measures adopted, the ozone layer is recovering satisfactorily (1-3% per decade since 2000) and it is believed that stratospheric ozone levels will reach pre-1980 levels by 2030 in the Northern Hemisphere, 2050 in the Southern Hemisphere and 2060-2070 in the polar regions.

But the reading we should make of the successful management derived from the Montreal Protocol goes beyond the recovery of stratospheric ozone, as it offers valuable lessons to be applied to similar problems. First, the speed at which decisions were made. In 1974, two researchers at the University of California (Irvine), Frank Sherwood Rowland and Mario Molina, discovered that CFCs, highly successful compounds in industry and harmless in the lower atmosphere, caused ozone destruction in the stratosphere. Although this discovery led them to win the Nobel Prize in chemistry in 1995 (together with the Dutchman Paul Crutzen), at that time it went unnoticed until a group of researchers from the British Antarctic Survey, led by Joseph Farman, detected a surprising decrease in stratospheric ozone over Antarctica. The year was 1985 and it was the first observation of the ozone hole. From then on, events followed one after the other with great speed. In 1985, the Vienna Convention for the Protection of the Ozone Layer was created, which resulted in the successful Montreal Protocol, adopted only two years later, on September 16, 1987. This speed contrasts sharply with the management of another global environmental problem, climate change, where multinational governance has been dragging its feet for decades.

The second important aspect of the Montreal Protocol is the continuous monitoring by the scientific community. The results of the measures adopted are periodically evaluated by a scientific panel, so that when the evolution does not correspond to expectations, they are modified through adjustments and amendments in which new substances are added or the year in which they are banned is brought forward. The Montreal Protocol has not only prevented millions of cases of skin cancer or cataracts by restoring the ozone layer, but has also reduced a large amount of CO2 equivalent by reducing the concentration of CFCs, HCFCs and HFCs, which also have a high greenhouse potential. The Montreal Protocol has shown that intense and coordinated international collaboration based on scientific criteria can be the best recipe for combating the global problems we face.

In this regard, Antonio Guterres, Secretary General of the United Nations, recently urged all countries to make the fight against global warming one of the key elements in their recovery strategies in the face of the pandemic. There are no shortcuts; both problems must be tackled in a coordinated manner, based on multilateral collaboration and political loyalty. And the Montreal Protocol can be the mirror in which to look.

The EU seems to have taken up the gauntlet and is leading the global fight against climate change, driving decisions in this direction even at a time of extreme complexity such as the present. A few days ago, the European Parliament approved a 60% reduction in CO2 emissions by 2030, instead of the 40% established until now, on the road to climate neutrality in 2050. Let's hope that this is the line to follow and that this does not remain just an idea on paper. Our future depends on it.