Al Amn Magazine # 160

37 FEBRUARY 2023 Protection Agency, eradicating ozone much more quickly than it can be replaced. Molina and Rowland’s work received striking validation in 1985, when a team of English scientists found a hole in the ozone layer over Antarctica that was later linked to CFCs. The “hole” is actually an area of the stratosphere with extremely low concentrations of ozone that reoccurs every year at the beginning of the Southern Hemisphere spring (August to October). Spring brings sunlight, which releases chlorine into the stratospheric clouds. The ozone layer’s status today Recognition of the harmful effects of CFCs and other ozone-depleting substances led to the Montreal Protocol on Substances That Deplete the Ozone Layer in 1987, a landmark agreement to phase out those substances that has been ratified by all 197 UN member countries. Without the pact, the U.S. would have seen an additional 280 million cases of skin cancer, 1.5 million skin cancer deaths, and 45 million cataracts— and the world would be at least 25 per cent hotter. More than 30 years after the Montreal Protocol, NASA scientists documented the first direct proof that Antarctic ozone is recovering because of the CFC phase-down: Ozone depletion in the region has declined 20 per cent since 2005. And at the end of 2018, the United Nations confirmed in a scientific assessment that the ozone layer is recovering, projecting that it would heal completely in the (non- polar) Northern Hemisphere by the 2030s, followed by the Southern Hemisphere in the 2050s and polar regions by 2060. Monitoring of the ozone layer continues, and it’s finding that the recovery may not be as straightforward as hoped. A study in early 2018 found that ozone in the lower stratosphere unexpectedly and inexplicably has dropped since 1998, while another pointed to possible ongoing violations of the Montreal pact. The world is not yet in the clear when it comes to harmful gases from coolants. Some hydrochlorofluorocarbons (HCFCs), transitional substitutes that are less damaging but still harmful to ozone, are still in use. Developing countries need funding from the Montreal Protocol’s Multilateral Fund to eliminate the most widely used of these, the refrigerant R-22. The next generation of coolants, hydrofluorocarbons (HFCs), do not deplete ozone, but they are powerful greenhouse gases that trap heat, contributing to climate change. Though HFCs represent a small fraction of emissions compared with carbon dioxide and other greenhouse gases, their planet- warming effect prompted an addition to the Montreal Protocol, the Kigali Amendment, in 2016. The amendment, which came into force in January 2019, aims to slash the use of HFCs by more than 80 percent over the next three decades. In the meantime, companies and scientists are working on climate- friendly alternatives, including new coolants and technologies that reduce or eliminate dependence on chemicals.