The ozone gap that varieties yearly over Antarctica has grown for the third yr in a row.
At almost 10 million sq. miles (26.4 million sq. kilometers), the ozone hole (opens in new tab) is the most important it has been since 2015. However regardless of that progress, scientists say that the outlet’s measurement continues to be on a downward pattern total. “All the information says that ozone is on the mend,” Paul Newman, NASA Goddard Space Flight Center‘s chief Earth scientist, instructed the Associated Press (opens in new tab).
The ozone gap was first observed in the early 1980s (opens in new tab) and reached its largest extent in 2006 (opens in new tab), based on NASA. This yr’s ozone gap, which peaked on Oct. 5, was the largest recorded since 2015. However scientists aren’t too involved. “The general pattern is enchancment. It is a bit of worse this yr as a result of it was a bit of colder this yr,” Newman instructed the Related Press.
Associated: See how the huge ozone hole over Antarctica has grown in 2021 in this NASA video
Ozone consists of three oxygen atoms and makes up little or no of our ambiance, but it surely has a big impact on our planet. The blanket-like layer stretching over the globe absorbs probably the most dangerous ultraviolet (UV) radiation from the sun, shielding life on Earth. Ozone varieties within the stratosphere, round 9 to 18 miles (14.5 to 29 kilometers) above Earth’s floor. It varieties when UV radiation splits common oxygen molecules, that are made from two oxygen atoms (O2); the 2 free-floating oxygen atoms then every bond with an oxygen molecule, forming a molecule made from three oxygen atoms.
Scientists found the thinning ozone layer over Antarctica within the early Nineteen Eighties. Though ozone is created and destroyed naturally within the stratosphere, human-driven air pollution destroys ozone sooner than it will possibly type. Specifically, applied sciences that use chlorine or bromine, like refrigeration and air-con, destroy ozone at alarmingly excessive charges. Within the stratosphere, chlorine molecules react with ozone to create one chlorine monoxide molecule (composed of a chlorine atom and an oxygen atom) and one O2 molecule. That chlorine monoxide molecule then breaks down, releasing that chlorine atom to react with extra ozone. Based on the Environmental Safety Company, one atom of chlorine can destroy 100,000 ozone molecules (opens in new tab) earlier than that chlorine molecule is faraway from the ambiance.
Substances like chlorofluorocarbons, utilized in refrigeration and air-con, keep within the ambiance for a very long time — some for longer than six months — that means the chlorine and different chemical compounds from these substances can wreak havoc on the ozone layer.
A chilly stratosphere is precisely what chemical compounds like chlorine want to interrupt down ozone. Throughout Antarctica’s winter, the stratosphere will get chilly sufficient for clouds to type. The ice crystals that make up these clouds present a floor on which chlorine, for example, can react with ozone. As spring approaches in September, the sun’s UV rays jumpstart these reactions. As soon as summer time is in full swing, the stratosphere warms up sufficient to evaporate the clouds, eradicating the floor on which ozone-destroying chemical reactions happen.
International agreements just like the Montreal Protocol (opens in new tab), which regulates the manufacturing and consumption of ozone-depleting substances, have helped to repair the ozone gap. And regardless of the ozone gap’s rising measurement this yr, scientists usually agree that the outlet is shrinking.
Earlier this yr the Nationwide Oceanic and Atmospheric Administration reported that ozone-depleting substances within the ambiance have decreased by 50% (opens in new tab) since 1980. The report additionally famous that if this downward pattern continues, the ozone layer could possibly be totally repaired by 2070.
Initially printed on Dwell Science.
