2019 sees smallest ozone hole
Hole in the ozone layer is now the smallest it has been on record since it was discovered in 1982, confirm researchers
The ozone hole over Antarctica is the smallest observed since 1982, due to abnormally warm temperatures in the upper atmosphere that dramatically limited ozone depletion in September and October this year, according to NASA and NOAA satellite measurements.
However, the researchers at NASA and The National Oceanic and Atmospheric Administration (NOAA) cautioned that this is due to warmer stratospheric temperatures and not a sign that atmospheric ozone is suddenly on a fast track to recovery.
The annual ozone hole reached its peak extent of 16.4 million square kilometers on September 8, and then shrank to less than 10 million square kilometers for the remainder of September and October, NASA said in a statement.
During years with normal weather conditions, the ozone hole typically grows to a maximum area of about eight million square miles in late September or early October, it said. “It’s great news for ozone in the Southern Hemisphere,” said Paul Newman, chief scientist for Earth Sciences at NASA’s Goddard Space Flight Center in the US.
“But it’s important to recognise that what we’re seeing this year is due to warmer stratospheric temperatures. It’s not a sign that atmospheric ozone is suddenly on a fast track to recovery,” Newman said. Ozone is a highly reactive molecule comprised of three oxygen atoms that occurs naturally in small amounts.
Roughly seven to 25 miles above Earth’s surface, in a layer of the atmosphere called the stratosphere, the ozone layer is a sunscreen, shielding the planet from potentially harmful ultraviolet radiation that can cause skin cancer and cataracts, suppress immune systems and also damage plants.
The Antarctic ozone hole forms during the Southern Hemisphere’s late winter as the returning Sun’s rays start ozone-depleting reactions. These reactions involve chemically active forms of chlorine and bromine derived from manmade compounds. The chemistry that leads to their formation involves chemical reactions that occur on the surfaces of cloud particles that form in cold stratospheric layers, leading ultimately to runaway reactions that destroy ozone molecules.