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The Ozone Was Healing. Now It's in Jeopardy.

A mysterious surge in an ozone-depleting emission was recently detected coming from East Asia, according to the New York Times — and if the source isn’t stopped, it could reverse the progress that has been made in healing the atmosphere.

Stephen Montzka, a scientist working at the US National Oceanic and Atmospheric Administration (NOAA), observed a sudden spike in the chemical known as CFC-11 during routine inspections of the atmosphere.

The substance was found in the atmosphere above Hawaii after being blown there from East Asia, according to NOAA, whose findings were published in the scientific journal Nature on Wednesday. Pinpointing the exact location of the emissions is possible, but it will require further research.

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“I have been doing this for 27 years and this is the most surprising thing I’ve ever seen,” he told the Guardian. “I was just shocked by it.”

“We are acting as detectives of the atmosphere, trying to understand what is happening and why,” he added. “When things go awry, we raise a flag.”

Chlorofluorocarbons, or CFCs, are chemicals that were once used for foam insulation, in aerosols, and as refrigerants.

Rwanda Climate Meeting to ban HFCs, greenhouse gas found in air conditions and refrigeratorsImage: AP Photo/Desmond Boylan, File

They were globally banned in 2010 under the Montreal Protocol after it was discovered that they were tearing a hole in the ozone layer, exposing the Earth’s surface to higher levels of ultraviolet radiation.

When countries started to enforce the ban, the hole began to shrink steadily. Scientists believed that it would entirely heal by mid-century, allowing the ozone to resume its normal role as an atmospheric shield, the Times reports.

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But that hope has been jeopardized by the unexpected discovery, according to the Guardian.

“If these emissions continue unabated, they have the potential to slow down the recovery of the ozone layer,” Erik Solheim, head of UN Environment, told the Guardian. “It’s therefore critical that we identify the precise causes of these emissions and take the necessary action.”

The New York Times posits that the emissions could be coming from the demolition of buildings with foam insulation, or a country may be flouting the Montreal Protocol’s ban on the substance.

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Even if the source is identified, CFC-11 has a lifetime of 50 years, so it may slow the ozone's recovery for decades.

"Let's be clear that the CFC-11 concentration is still going down,” Montzka told the Times. If the new emissions go away soon, he said, “it won’t have much of an impact on the timetable for ozone recovery.”

“I’m hoping that once this flag is raised and awareness increases there will be significant efforts to identify the source,” he added.

The emergence of CFC-11 is a reminder of how hard it is to enforce global environmental treaties, and may hint at trouble ahead for the Paris climate agreement, the global pact that aims to mitigate climate change by reducing greenhouse gas emissions.

Global Citizen campaigns on the United Nations’ Global Goals, which call on countries to honor the Montreal Protocol. You can take action on this issue here.