Feb 11, 2021 - Science

"Abrupt turnaround": Emissions from ozone-destroying chemicals drop

The false-color view of the monthly-averaged total ozone over the Antarctic pole.

An image representing the monthly-averaged total of ozone over Antarctica as of February 2021. "The blue and purple colors are where there is the least ozone," per NASA. Photo NASA Goddard Space Flight Center

Emissions of ozone-depleting CFC chemicals are back on the decline, five years on from a major spike, an international team of researchers has found.

Why it matters: The surprising findings indicate "we should see recovery of the ozone layer back to levels that we saw in 1980" later this century, said Luke Western, lead author of one of two papers published on the matter in the journal Nature Wednesday, per the BBC.

An image of the hole in the ozone layer over Antarctica in 2000.
A 2000 image of the hole in the Earth's protective ozone layer, which absorbs most of the Sun's potentially harmful ultraviolet rays, over Antarctica. Photo: Newsmakers via Getty Images

For the record: Atmospheric measurements in 2018 detected emissions of the chlorofluorocarbons compound known as CFC-11 coming from factories in Eastern China. The banned pollutant has been used to produce items including foam insulation for refrigerators, air conditioners and buildings.

  • Researchers discovered that from 2014 to 2016, emissions of CFC-11 had risen by over 14,000 tons per year to about 65,000 U.S. tons per year — a 25% a jump above average emissions from 2002 to 2012, with 60% of this rise coming from eastern China.
  • In response to an international outcry over the first known substantive violation of the international environmental treaty known as the Montreal Protocol, China announced renewed enforcement and inspections measures.

What they found: Results of the first paper, titled "A decline in global CFC-11 emissions during 2018−2019," show that emissions of CFC-11 for this period fell globally by about 20,000 tons a year to 57,000 U.S. tons — a drop of 26%.

  • The second paper, "A decline in emissions of CFC-11 and related chemicals from eastern China," found CFC-11 emissions in this region in 2019 fell by 11,000 tons per year, compared with 2014 to 2017 — a 33% drop and a return to pre-2013 levels of 5,500 U.S. tons per year.
  • Current annual emissions now appear to have returned to pre-2012 levels, per a statement from NASA, which detected what it called an "abrupt turnaround."

What they're saying: Regional paper co-author Matthew Rigby, a scientist at Britain's University of Bristol, said in a statement it's "extremely surprising to see the rapid turnaround that was indicated by the data, globally and in eastern Asia."

  • "Even more remarkable was when we calculated the emissions changes and saw that the decline over one or two years was as large as, or perhaps bigger than, the original rise," Rigby added.

Yes, but: British scientist Craig Poku, from the University of Leeds told the New Scientist the emissions decline in eastern China was "promising," but "it's too early to say" whether the trend will continue.

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