Sunday, January 3, 2016

Ten years of hole in the ozone layer

Ten years of hole in the ozone layer

The effective international ban on chlorofluorocarbons can be considered a good precedent. The ozone hole is back to break records in this Antarctic season, yes. But, unlike what happens with climate change, there is no reason for alarm. The international Montreal Protocol signed in 1987 is working well, the ban on CFCs (chlorofluorocarbons) and other ozone-depleting gases has given way to other harmless compounds to the atmosphere and the World Meteorological Organization of the United Nations predicts that ozone it will recover over the next 10 years. What then is this hole record at the South Pole? What we are seeing is a combination of two factors. The first is the annual climatic oscillations during the austral season have been characterized by unusually low temperatures in the stratosphere. The cold in these upper layers, together with increased solar radiation that has accompanied the spring at the South Pole, have created optimal conditions for the chemical destruction of ozone there that were not met since 2006. This is a factor conditions on that human activity does not have much to say.

The second factor is more interesting: we are still paying the bill passed. As scientists knew in the seventies and eighties, CFCs are catalysts of ozone depletion: very low concentrations in the atmosphere enough to plant damage, and its persistence in the upper ago that we are still seeing the effects of what we emit decades. This factor itself is due to human activity, but in this case, paradoxically, only to be welcomed by the actions taken by the governments. It's just that you have to have some patience: ten years of patience, experts say.

None of this downplays the problem. The severity of the ozone loss is due to its direct and negative effects on health. Ozone is the main natural screen against ultraviolet radiation contained in sunlight, and therefore increases its destruction rates of skin cancer, cataracts and genetic damage the immune system. These harmful effects are particularly acute in polar regions, especially in Antarctica, but leave also felt in the rest of the planet. For these reasons, UN scientists estimate that the Montreal Protocol will eventually prevent two million cases of skin cancer in 2030.

Despite the seasonal and annual variations, international action against ozone hole can be considered an excellent precedent. The first article on the subject of Paul Crutzen dates from 1969, and the worthy work of Nobel Mario Molina and Sherwood Rowland, who identified CFCs as guilty, were published in the seventies. The problem is already poised for a solution itself can be considered a record, compared to the deadlines that have been managing for climate change. Take example.