Scientists say there are promising signs for the ozone layer over Antarctica, but trends will need to continue for several more decades before this critical layer of the stratosphere is fully recovered.According to NOAA’s annual ozone summary, the layer’s depletion from Sept. 7 to Oct. 13 ranked as the seventh smallest since monitoring began in 1992. While the hole in the ozone layer was still considerable – estimated to be three times the size of the contiguous United States – its size has generally continued to decline. “The 2024 Antarctic hole is smaller than those seen in the early 2000s,” Paul Newman, a member of NASA’s ozone research team, said in a statement. “This gradual improvement over the past two decades indicates that international efforts to curb ozone-destroying chemicals are working.”ARKANSAS HIDDEN TREASURE: VAST AMOUNTS OF LITHIUM HIDING UNDERGROUNDScientists attribute some of the improvements to a decline in chlorofluorocarbons or what are commonly called CFCs.These chemical compounds were once used as refrigerants, propellants and solvents but led to the destruction of ozone molecules in the stratosphere.Countries signed pacts and committed to phasing out CFCs starting in the late 1980s, leading to an estimated decline of over 90% from peak levels.”For 2024, we can see that the ozone hole’s severity is below average compared to other years in the past three decades, but the ozone layer is still far from being fully healed,” Stephen Montzka, a scientist at NOAA’s Global Monitoring Laboratory, stated.In addition to satellites orbiting Earth, NOAA scientists rely on weather balloons to conduct observations in measurements called Dobson Units.The lowest ozone value ever recorded over the South Pole was 92 Dobson Units in October 2006. The 2024 value was reported to be 109 Dobson Units, which was about half the value recorded during the 1970s.”This is well below the 225 Dobson Units that was typical of the ozone cover above the Antarctic in 1979,” Bryan Johnson, a NOAA research chemist, said in a statement. “So, there’s still a long way to go before atmospheric ozone is back to the levels before the advent of widespread CFC pollution.”ANTARCTICA’S ‘DOOMSDAY GLACIER’ IS MELTING AWAY DIFFERENTLY THAN SCIENTISTS FIRST THOUGHTAs scientists continue to monitor the ozone’s evolution, many remain hopeful for its recovery during the coming decades.Based on analysis from NOAA and NASA, the U.S. agencies estimate that if positive trends continue, the ozone layer over the Antarctic could fully recover by 2066.A recovery of the ozone would allow Earth to block more harmful ultraviolet radiation from the Sun, leading to less damaging impacts on humans and ecosystems.