The ozone layer is on its way to recovery

The ozone layer is on track to recover over the next four decades, and the global phase-out of ozone-depleting chemicals is already contributing to climate change mitigation. That’s the conclusion of the UN-backed panel of experts, which was presented today at the 103rd Annual Meeting of the American Meteorological Society. Studying new technologies such as geoengineering for the first time, the group warned of the unintended effects this technology could have on the ozone layer.

On the way to a full recovery

in it Quadruple evaluation report The UN-backed Scientific Assessment Panel of the Montreal Protocol on Substances that Deplete the Ozone Layer confirms that the phase-out of nearly 99% of banned ozone-depleting substances has successfully protected the ozone layer and contributed to its remarkable recovery in the ozone layer. The upper stratosphere and decreasing human exposure to harmful ultraviolet radiation from the sun.

If current policies are maintained, the ozone layer is expected to return to 1980 values ​​(before the formation of the ozone hole) around 2066 in the Antarctic, in 2045 in the Arctic, and in 2040 in the rest of the world. Variations in the size of the Antarctic ozone hole, especially between 2019 and 2021, are mainly due to weather conditions. However, it should be noted that the area and depth of the ozone hole has decreased since the year 2000.

“According to the latest quadrennial report, the ozone layer is recovering, which is great news. It can never be emphasized enough how much the Montreal Protocol contributes to climate change mitigation,” said Meg Seki, Executive Secretary of the Ozone Secretariat of the United Nations Environment Program (UNEP). ), over the past 35 years, the Protocol has become a true champion of the environment.” Assessments and reviews by the Scientific Assessment Panel continue to be an essential component of the Protocol’s work, helping to inform policy and decision makers.”

Positive impact on climate change

The tenth report of the Scientific Assessment Panel confirms the treaty’s positive impact on climate. The Kigali Amendment to the Montreal Protocol, an additional agreement reached in 2016, requires the production and use of certain hydrofluorocarbons (HFCs) to be phased out. HFCs do not directly deplete ozone, but they are powerful greenhouse gases. According to the Scientific Assessment Panel, this modification should contribute to avoiding 0.3-0.5°C of global warming by 2100 (the contribution from HFC-23 emissions is not included).

“The measures taken with regard to ozone set a precedent for climate action. The success of the phase-out of ozone-depleting chemicals shows us what can and must be done – urgently – to move away from fossil fuels, reduce greenhouse gas emissions and thus increase global warming,” said the Secretary-General. the heat “. World Meteorological Organization (WMO), Professor Petteri Taalas.

The latest assessment is based on extensive studies, research, and data collected by a large international group of experts, many from the World Meteorological Organization (WMO), the United Nations Environment Program, the National Oceanic and Atmospheric Administration (NOAA), and the National Aeronautics and Space Administration. Administration (NASA) and the European Union.

Geological engineering

For the first time, the Scientific Assessment Panel has examined the potential effects on ozone of stratospheric aerosol injection (SAI). SAI has been proposed as a possible way to reduce global warming by increasing the reflection of sunlight. However, the group warns of unintended consequences of the device, which “could also affect temperatures, circulation, and rates of stratospheric ozone production and destruction, as well as transportation.”

Line: United Nations Environment Program

more information:

Montreal Protocol

Information Center of the United Nations Regional Center for the Eastern Mediterranean – United Nations Resources