A new state analysis of the ozone layer has determined that this ‘natural shield’ Earth could recover by midcentury if further measures to restrict emissions from products that destroy .
The study has been supported by the World Meteorological Organization (WMO) and by the Programme of the United Nations Environment Programme (UNEP). In developing the first thorough evaluation made in the past four years have participated 300 renowned scientists , which have concluded that thanks to the measures taken by the “Montreal Protocol Substances that Deplete the Ozone Layer “, in force since 1989, is on target to recover the reference levels of 1980 , when there was still no significant signs of exhaustion.
The report states that, if not for this protocol, levels of atmospheric concentration of harmful gases could have reached tenfold before 2050, however, it appears that the process has been reversed.
The most harmful substances are CFC gases (clorofluorurocarbonos) and halons. These products are used in refrigerators, spray, insulating foams and firefighting equipment.
In 1987, these substances were nearly ten gigatons, about seven times the destructive power of the bombs that destroyed Hiroshima and Nagasaki , of carbon dioxide. Theoretically, these emissions today have declined more than 90% . In practice, it is known that there were overall reductions in the ozone layer in the decades of the 80s and 90s, in the 2000s there was a stalemate and there are currently signs of recovery .
According to UNEP estimates, the implementation of the Montreal Protocol, avoided two million annual cases of skin cancer in 2030, in addition to preventing eye injuries, damage to the human immune system, and protect the fauna, flora and agriculture.
Eliminating harmful substances has also had side effects beneficial for the global climate , since many of these substances are also gases with potent greenhouse.
However, the study also warns that the rapid increase of certain substitutes , which are also potent greenhouse gases, could miss ground gained . In fact, scientists warn that he may face the fate of ozone in the second half of this century depends, above all, of the concentrations of carbon dioxide, methane and nitrous rust, three main gases remain in the atmosphere.
the group is expected to present the Scientific Assessment main conclusions of the new report at the Annual Meeting of the Parties to the Montreal Protocol to be held in Paris in November 2014 .
Despite signs of recovery, the hole over Antarctica is still forming every spring and this trend is expected to continue for most of this century, given the persistence in the atmosphere of harmful substances , although it is no longer issued.
Ozone depletion in this continent has contributed to the cooling of the lower stratosphere, which is probably the main cause of the recorded in the southern hemisphere summers Changes recent decades, with consequent effects on surface temperature, precipitation and oceans, as specified by the report.
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