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For decades, ozone layer seemed to shrink inexorably. However, because it is indispensable for life on Earth, governments of world responded in year 1987 and adopted Montreal Protocol, in which States pledged to use ozone-destroying chemicals such as chlorofluorocarbons (CFCs) to dispense with. The production of substances has been banned since 2010. The ozone layer is refore recovering altoger, even if it was abnormally thin in meantime, approximately in year 2016.
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Now a study suggests: concentration of a CFC called Trichlorfluormethan (CFC-11) is slower than expected because re is a previously unknown, large source of chemicals (nature: Montzka et al. 2018). The diploma physicist Jens-Uwe Grooß explains how results are to be classified and what this means for future size of Ozonslochs.
Online Time: Last it was said that ozone hole close slowly. Researchers suspected that by middle of this century, Earth’s protective cover could even be completely intact again. Now a new study is to show that it could take longer – because someone has been chasing banned substances into atmosphere that is damaging ozone layer for a few years. What do you think of it?
Grooß: First and foremost, I find results of study surprisingly. The production of Trichlorfluormethan (CFC-11) – That’s gas we’re talking about – has actually been banned more than 20 years ago. The waiver has long and successfully made sure that ozone hole slowly retracts. It’s been proven that this worked. But approximately since 2012, re seems to be a new production of CFCs somewhere. I think that analyses carried out by Stephen Montzka and his colleagues are conclusive.
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Chlorofluorocarbons (CFCs) have been outlawed internationally since 1989. Many states have refrained from doing so, but production is now banned. The CFC pollution in atmosphere has refore decreased. Last (red line) but not as strong as predicted (dashed line).
Source: Nature: Montzka et al. 2018
Time Online: Why do authors suspect a crime here?
Grooß: Because a lot of things suggest that even larger amounts of CFCs are being produced secretly somewhere. The United Nations Environment Programme is responsible for monitoring. The production of all ozone-hazardous substances worldwide must be reported precisely re. The employees keep an eye on few CFC sources that still exist on Earth. These are mostly so-called banks, from which CFCs are still entering atmosphere. These include, for example, old refrigerators that were not properly disposed of, or buildings in which Styrofoam was installed and which are now demolished.
Jens-Uwe Grooß is a physicist at Institute for Energy and Climate Research at research Center Jülich. © Ralf-Uwe Limbach/Forschungszentrum Jülich
Montzka and his colleagues could exclude banks as a cause, as re is no reason why y should have increased abruptly from 2012. So re has to be someone who still produces CFCs somewhere. I believe that this conclusion is understandable. No one can judge wher or not someone is really criminal.
time Online: Supposedly source of emissions lies in Souast Asia. How to get to it?
Grooß: There are very precise measuring methods that have been used by scientists worldwide to determine how much CFCs exist for decades. This results in patterns: In some places, CFC values decrease slower than y should. This can n be indirectly related to emissions. In this case, increased emissions in Souast Asia.
