The Ozone Layer Continues to Decline
A recent study suggests that although the ozone is recovering from human-caused thinning, some parts are still in trouble
Part of the ozone layer is still thinning, according to a Scientific American article published in February. In 1985, scientists first reported a hole above the Antarctic in the ozone—an atmospheric layer that is important for absorbing harmful ultraviolet rays from the sun. The hole was caused by chlorofluorocarbons (CFCs), toxic chemicals released by aerosols and refrigerants. Since the creation of an international agreement that led to the phase-out of such chemicals, the ozone layer had been recovering. But the recent study finds the part of the atmosphere with the most ozone—the lower stratosphere—is still seeing a decline. According to the researchers, the global ozone layer shrank by 5 percent from 1970 to 1998. Yet even after those harmful chemicals were phased out, the layer declined another 0.5 percent, the study found. The scientists do not know why—some explanations point to climate change; another implicates chemicals that humans continue to release into the atmosphere.