Rise in Ozone-Destroying Chemical Despite Ban Puzzles Scientists

James Marshall
May 17, 2018

New research from the National Oceanic and Atmospheric Administration in Boulder suggests there are new sources of a banned ozone depleting chemical.

The standard reference for CFC concentrations, the United Nations Environment Program's Handbook for the Montreal Protocol, reported in its 2012 edition that production of CFC-11 was very close to zero.

"The authors pinpoint a new source of CFC-11 to East Asia, breaking Montreal Protocol rules".

The finding seems likely to prompt an global investigation into the mysterious source. The finding matters because ozone layer in the stratosphere helps filter skin cancer-causing ultraviolet radiation.

The slowdown in reduction of CFC-11 also has implications for the fight against climate change. Production was banned, emissions fell and the hole slowly shrank.

The issue involves a gas called CFC-11, a chlorofluorocarbon that contributes to the depletion of the ozone layer. This conclusion was confirmed by other changes recorded in NOAA's measurements during the same period, such as a widening difference between CFC-11 concentrations in the northern and southern hemispheres - evidence that the new source was somewhere north of the equator.

The UNEP said that is was "critical that we take stock of this science, identify the causes of these emissions and take necessary action".

Because CFC-11 still accounts for one-quarter of all chlorine present in today's stratosphere, expectations for the ozone hole to heal by mid-century depend on an accelerating decline of CFC-11 in the atmosphere as its emissions diminish- which should happen with no new CFC-11 production.

CFC-11, used primarily for foams, can last up to 50 years in the atmosphere once it is released. "In the end, we concluded that it's most likely that someone may be producing the CFC11 that's escaping to the atmosphere", he said. "It is therefore imperative that this finding be discussed at the next Ministerial meeting of Governments given recovery of the ozone layer is dependent on all countries complying with the Montreal Protocol (and its adjustments and amendments) with emissions globally dropping to zero". "But we don't know of any folks who are destroying buildings at a much more dramatic rate than they were before", said Montzka.

Unreported production of CFC-11 outside certain specific carve-out purposes in the treaty would be a "violation of global law", Weller confirmed, though he said that the protocol is "non-punitive" and the remedy would probably involve a negotiation with the offending party or country. "I have a feeling that we will find out fairly quickly what exactly is going on and that the situation will be remedied", he said. But the apparent increase in emissions of CFC-11 has slowed the rate of decrease by about 22 percent, the scientists found.

Other reports by Click Lancashire

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