The earth’s ozone layer is on track to repair itself in four decades.
Researchers have even found a significant thickening of the ozone layer compared to 2018 levels, according to a report released yesterday (Jan. 9) by the United Nations Environment Program (UNEP) and the World Meteorological Organization (WMO). The group of UN-backed scientists, who publishes an assessment every four years, credits a decline in airborne chemicals for the recovery, finding that nearly 99% of banned ozone-depleting substances have been phased out.
For decades, the 9- to 18-mile high atmospheric layer that protects humans from harmful ultraviolet rays emitted by the sun had been damaged by chlorofluorocarbons (CFCs) and halons. A thinner or broken ozone layer is associated with increased prevalence of skin cancer and cataracts, reduced agricultural productivity, and disruption of marine ecosystems, among other things.
“If current policies remain in place, the ozone layer is expected to recover to 1980 values (before the appearance of the ozone hole) by around 2066 over the Antarctic, by 2045 over the Arctic and by 2040 for the rest of the world,” the UNEP said.
1930s: Inventor Thomas Midgeley introduces the world to CFCs. The cheap, non-flammable coolants are used in refrigerators, air conditioning, fast food packaging, propellants, and more for decades to come. CFCs rise and accumulate in the stratosphere, where they are broken down by the sun’s ultraviolet light, releasing chlorine atoms in the process. One chlorine atom can destroy upwards of 10,000 ozone molecules.
1974: Scientists Mario Molina and Sherwood Rowland, two chemists at the University of California, Irvine, publish an article in scientific journal Nature, detailing ozone depletion caused by human-generated CFCs.
1985: Three scientists from the British Antarctic Survey publish a piece in Nature, reporting on the phenomenon of the annual springtime ozone hole appearing in Antarctica in the ‘80s. The hole will grow through the 1990s and 2000s.
1987: The Montreal protocol banning CFCs is signed by 46 countries. It calls for the eventual worldwide CFC reduction of 50% by 1999. Over the years, several amendments will be made to it—London (1990), Copenhagen (1992), Vienna (1995), Montreal (1997), Beijing (1999), Kigali (2016)—to bring forward phase out schedules and add new substances to the list of substances controlled, and the list of signatory nations grows to 200.
1989: Montreal agreement goes into effect on Jan. 1.
1990s: While many countries strive to pull back emissions from CFCs, others like China, South Korea, and the Philippines actually end up raising emission levels.
“Ozone action sets a precedent for climate action. Our success in phasing out ozone-eating chemicals shows us what can and must be done–as a matter of urgency–to transition away from fossil fuels, reduce greenhouse gasses and so limit temperature increase.” -WMO Secretary-General Petteri Taalas