Earth's ozone layer is finally healing, UN says

 Earth’s protective ozone layer is finally healing from damage caused by aerosol sprays and coolants, a new United Nations report said. The ozone layer had been thinning since the late 1970s. Scientist raised the alarm and ozone-depleting chemicals were phased out worldwide. As a result, the upper ozone layer above the Northern Hemisphere should be completely repaired in the 2030s and the gaping Antarctic ozone hole should disappear in the 2060s, according to a scientific assessment released Monday at a conference in Quito, Ecuador. The Southern Hemisphere lags a bit and its ozone layer should be healed by mid-century. High in the atmosphere, ozone shields Earth from ultraviolet rays that cause skin cancer, crop damage and other problems. Use of man-made chemicals called chlorofluorocarbons (CFCs), which release chlorine and bromine, began eating away at the ozone. In 1987, countries around the world agreed in the Montreal Protocol to phase out CFCs and businesses came up with replacements for spray cans and other uses. At its worst in the late 1990s, about 10 percent of the upper ozone layer was depleted, said Newman. Since 2000, it has increased by about 1 to 3 percent per decade, the report said. This year, the ozone hole over the South Pole peaked at nearly 9.6 million square miles (24.8 million square kilometers). That’s about 16 percent smaller than the biggest hole recorded — 11.4 million square miles (29.6 million square kilometers) in 2006. The hole reaches its peak in September and October and disappears by late December until the next Southern Hemisphere spring. The ozone layer starts at about 6 miles (10 kilometers) above Earth and stretches for nearly 25 miles (40 kilometers); ozone is a colorless combination of three oxygen atoms. If nothing had been done to stop the thinning, the world would have destroyed two-thirds of its ozone layer by 2065. Another problem is that new technology has found an increase in emissions of a banned CFC out of East Asia. An amendment to the Montreal Protocol that goes into effect next year would cut use of some of those gases.