The next release of ozone-depleting substances into the atmosphere indicated the opening of a new production of freon, which had been banned for more than 30 years.
Non-toxic, extremely inert chlorofluorocarbons (CFCs) have long been considered completely safe and have been widely used as refrigerants in refrigerators, propellants in aerosol cans, and so on. However, by the 1970s, it became clear that these volatile compounds can accumulate in the upper atmosphere, where they decompose under the influence of ultraviolet radiation, releasing atomic chlorine, which destroys ozone molecules.
The risk of leaving the planet without protection from the mutagenic radiation of the Sun scared mankind quite strongly, and since 1987 the Montreal Protocol has been in effect, by virtue of which the lower volatile CFCs were finally banned from production. These measures have had an effect: in recent years, ozone holes that have emerged over the Antarctic have been decreasing.
But the more unexpected and alarming is the report by Stephen Montzka of the National Oceanic and Atmospheric Administration (NOAA) and his colleagues. In an article published in the journal Nature, they note that in recent years, the level of the Montreal Protocol-regulated Freon (trichlorofluoromethane, CFC-11) in the atmosphere has begun to rise again.
The peak of its quantity was noted back in 1993, and to date it has decreased by 15 percent, but in recent years it has begun to increase again. According to climatologists, in the period 2014-2016, freon emissions increased by a quarter, returning to the level of 20 years ago, and the drop in its content in the air slowed down sharply.
The source of the new emissions remains unclear. At first, scientists associated them with leaks of old, closed industries and containers that contained freon. However, the picture does not agree with this: according to Montzky and his colleagues, somewhere unannounced production started working again. “I don’t know why this could have been done,” says the scientist. "Is it produced for a specific purpose or simply formed as a byproduct of another chemical process."
The volume of CFC-11 entering the atmosphere is estimated at 6.5-13 thousand tons annually. “We are raising a warning flag for the entire international community,” continues Stephen Montzka. “We point out," This is what is happening - and it is dangerous for the recovery of the ozone layer. " The findings indicate that the content of freon is higher in the northern hemisphere, and scientists suspect that the mysterious production may be deployed somewhere in Southeast Asia, Mongolia, China or the Korean Peninsula.
Sergey Vasiliev
Promotional video: