Madrid, 14 years (European Press)
Concentrations of layer 2 ozone-depleting chemicals in the atmosphere peaked in 2021 and are now beginning to decline.
These substances, hydrochlorofluorocarbons (HCFCs), were used as first-generation replacements for the more harmful chlorofluorocarbons, or CFCs, which were responsible for creating the spring hole in the ozone layer over Antarctica.
HCFCs also deplete ozone and trap heat in the atmosphere, but to a lesser extent than the CFCs they replaced in the manufacture of refrigerants, blowing agents and solvents.
In September 2007, the Parties to the Montreal Protocol decided to accelerate their program to phase out the production of HCFCs for use in the applications that account for the majority of atmospheric releases. Developed countries have phased out HCFCs by 2020. Developing countries have agreed to begin the phase-out process in 2013 and establish a full phase-out of HCFCs by 2030.
Lead author Luke Western, a research fellow at the University of Bristol's School of Chemistry, said the findings underscore the importance of establishing and following up on international agreements such as the Montreal Protocol on Substances that Deplete the Ozone Layer.
“Without the Montreal Protocol, this success would not have been possible, making it a resounding endorsement of multilateral commitments to combat the effects of human-induced climate change,” said Western, who began this work when he was a researcher at NOAA's Global Observing Laboratory. (NOAA). The research was published in the journal Nature Climate Change.
Five years earlier than expected
Using high-resolution measurements of air samples provided by the National Oceanic and Atmospheric Administration's (NOAA) Global Greenhouse Gas Reference Network and the Advanced Global Atmospheric Gas Experiment obtained from globally distributed atmospheric observatories, researchers were able to quantify the impact of ozone depletion and the effect of ozone layer sequestration. the heat. of HCFCs peaked five years earlier than expected.
Adopted in 1987, the Montreal Protocol is a multilateral environmental agreement that established controls on the production of ozone-depleting substances such as CFCs. CFCs were widely used in the manufacture of hundreds of products, including aerosols, refrigerants, blowing agents for foams and packaging, and solvents.
Scientists hope that compliance with the controls agreed upon by the parties to the Montreal Protocol will restore the stratospheric ozone layer by 2065, preventing 443 million cases of skin cancer, about 2.3 million deaths from skin cancer and more than 63 million cases of cataracts in the United States. . countries alone, with greater benefits around the world.
Atmospheric concentrations of HCFCs are small (measured in parts per trillion) and their contribution to global warming has peaked at about 1% of total long-lived greenhouse gases and 2.8% of carbon dioxide. Once HCFCs escape into the atmosphere, they are more efficient than an equal amount of carbon dioxide at trapping heat in Earth's atmosphere that would escape into space. The warming resulting from the release of the most commonly used HCFCs over a 100-year period is about 2,000 times greater than that resulting from an equivalent amount of carbon dioxide.
