Banned ozone-destroying chemical on rise: scientists

The decline in the atmosphere of an ozone-depleting chemical banned by the Montreal Protocol has recently slowed by half, suggesting a serious violation of the 196-nation treaty, researchers revealed on Wednesday.

Measurements at remote sites, including the Mauna Loa Observatory in Hawaii, of the chemical, known as CFC-11, point to East Asia as the source or renewed production.

“We show that the rate of decline of atmospheric CFC-11 was constant from 2002 to 2012, and then slowed by about 50% after 2012,” an international team of scientists concluded in a study. “This evidence strongly suggests increased CFC-11 emissions from eastern Asia after 2012.”

The ozone layer in the stratosphere, 10-to-40 kilometres above Earth’s surface, protects life on the planet from deadly ultraviolet radiation.

The 1987 Montreal Protocol banned industrial aerosols such as chlorofluorocarbons (CFCs) that were chemically dissolving ozone, especially above Antarctica.

The findings, reported in Nature , also have implications for the fight against climate change. “Perhaps even more serious is the role of CFCs as long-lived greenhouse gases,” noted Joanna Haigh, a professor at Imperial College London.

Two decades ago, CFCs accounted for around 10% of human-induced global warming.

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