Hole in the ozone layer is closing and the CO2 can give a … – Reuters

             

                     
                 

                     
                 

                     

             

 
                     

The hole in the ozone layer is beginning to close, according to a new scientific assessment of one of the most publicized global environmental problems. And, amazingly, if we throw more greenhouse gases into the atmosphere – ie, those that are heating the planet – scarring can eventually be faster

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                     The future of the ozone layer has, however, several question marks, according to this new assessment released this Wednesday by the World Meteorological Organization (WMO) and the United Nations Program for Environment (UNEP, its acronym in English ). In an exercise that takes place every four years, three hundred scientists began to comb all that is known about the ozone layer, which shields the earth from ultraviolet rays.

The main conclusion is that the hole appeared in the 1980s due to chemicals used in aerosols, refrigerators, fire extinguishers and other applications gives strong signs of recovery.

In the 80s and 90s, the ozone concentration decreased about 2.5% on average globally, increasing the risk of diseases such as skin cancer and vision problems. The biggest problem is concentrated on the poles, where the ozone depletion is most significant.

Since 2000, however, the situation has been more or less stabilized with signs of some recovery in recent years . “There are positive indications that the ozone layer is on track to recover until the middle of the century,” says the Executive Director of UNEP, Achim Steiner in a statement. The forecast is that ozone levels in the midlatitude and Arctic return to 1980 values ​​before 2050 About Antarctica, this should happen a little later.

This is what the scientists hope will continue to be fulfilled Montreal Protocol -. treaty of 1987 which led to the progressive ban of products that deplete the ozone layer in the stratosphere, such as chlorofluorocarbons (CFCs) and halons

Achim Steiner says that the Montreal Protocol is “one of the most successful environmental treaties in the world.” And there are concrete reasons for this success: it was easy to find alternatives to those chemicals. And, more than that, there were few manufacturers. “The CFC production was almost all concentrated in a single company, DuPont,” recalls the physical Filipe Duarte Santos, Faculty of Sciences of Lisbon University and leader of several projects in the area of ​​climate change. “It’s completely different from what happens to the greenhouse gases, in which what is at stake is the whole energy paradigm we are living,” he adds.

The hole in the ozone layer and climate change issues are interlinked in complex ways and, in some cases, paradoxical, according to evidence evaluation from WMO and UNEP. The solution of the first to the second can cause problems. And, ironically, the aggravation of the second may help solve the first.

A major concern lies with hydrofluorocarbons (HFCs) have been used to replace CFCs. Besides destroying ozone in the stratosphere, CFCs also heat the planet. But HFCs are also greenhouse gases. “The climate benefits of the Montreal Protocol may be canceled by the expected emissions of HFCs,” says the study. The solution is to opt for forms of HFC with lower global warming potential or seek other alternatives.

The ozone-destroying gases remain active for decades in the stratosphere. But your concentration has already been declining. In the future, according to the study, which also have great influence on the ozone layer are the main greenhouse gases – carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). The first two are beneficial, ie, they tend to increase the ozone concentration. The third has the opposite effect.

No one knows, however, what will happen to the greenhouse gas emissions throughout this century. Based on scenarios of the Intergovernmental Panel on Climate Change, the report concludes that the higher the level of emissions, faster closes the hole in the ozone layer.

“The combined effects of CO2 levels, N2O and CH4 can accelerate the recovery of the ozone in two to four decades, “the study says.

Launching more gases that warm the Earth, however, is not all that either. Within two weeks, world leaders will meet with the Secretary General of the UN, Ban Ki-moon in New York to discuss the exact opposite: how to reduce emissions of greenhouse gases, to try to limit warming global 2 ° C by the end of the century. – a level considered bearable