The Earth’s ozone layer is expected to recover by 2040

POSTED ON Jan 18, 2023

It’s official: the ozone layer is on track to recover. According to the United Nations Environment Program (UNEP), responsible for coordinating responses to environmental issues within the UN system, the Earth’s atmosphere, which absorbs the sun’s harmful ultraviolet light, is healing.

The global phaseout of ozone-depleting chemicals is already benefitting 40 years of efforts to mitigate climate change.

The latest assessment has been made based on extensive studies, research, and data compiled by a large international group of experts, including many from the World Meteorological Organization (WMO), UNEP, the US National Oceanic and Atmospheric Administration (NOAA), the US National Aeronautics and Space Administration (NASA) and European Union.

The UN-backed panel announcement was first made at the American Meteorological Society’s 103rd annual meeting. The Scientific Assessment Panel to the Montreal Protocol on Ozone Depleting Substances assessment report, published every four years, confirms the phase-out of nearly 99% of banned ozone-depleting substances.

The Montreal Protocol has succeeded in safeguarding the ozone layer, leading to the recovery of the ozone layer in the upper stratosphere and decreased human exposure to harmful ultraviolet (UV) rays from the sun.

According to the UN, if current policies remain in place, the ozone layer is expected to recover to 1980 values (before the appearance of the ozone hole) by around 2066 over the Antarctic, by 2045 over the Arctic, and by 2040 for the rest of the world.

Variations in the size of the Antarctic ozone hole, particularly between 2019 and 2021, were primarily driven by meteorological conditions. Nevertheless, the Antarctic ozone hole has been slowly improving in area and depth since 2000.

“That ozone recovery is on track according to the latest quadrennial report is fantastic news. The impact of the Montreal Protocol on climate change mitigation cannot be overstressed. Over the last 35 years, the Protocol has become a true champion for the environment,” said Meg Seki, executive secretary of the United Nations Environment Programme’s Ozone Secretariat. “The assessments and reviews undertaken by the Scientific Assessment Panel remain a vital component of the work of the Protocol that helps inform policy and decision-makers.”

The Montreal Protocol is a global agreement to protect the Earth’s ozone layer by phasing out the chemicals that deplete it. The landmark agreement entered into force in 1989, one of the most successful global environmental agreements.

Thanks to the collaborative effort of nations around the world, the ozone layer is on its way to recovery, and many environmental and economic benefits have been achieved.

The 10th edition of the Scientific Assessment Panel reaffirms the positive impact that the treaty has already had on the climate. An additional 2016 agreement, known as the Kigali Amendment to the Montreal Protocol, requires a phase-down of the production and consumption of many hydrofluorocarbons (HFCs).

HFCs are powerful climate change gases that do not directly deplete ozone. The Scientific Assessment Panel said this amendment is estimated to avoid 0.3–0.5°C of warming by 2100 (this does not include contributions from HFC-23 emissions).

“Ozone action sets a precedent for climate action. Our success in phasing out ozone-eating chemicals shows us what can and must be done – as a matter of urgency – to transition away from fossil fuels, reduce greenhouse gases and so limit temperature increase,” said WMO Secretary-General Prof. Petteri Taalas.

For the first time, the Scientific Assessment Panel examined the potential effects on ozone of the intentional addition of aerosols into the stratosphere, known as a stratospheric aerosol injection (SAI). SAI has been proposed as a potential method to reduce climate warming by increasing sunlight reflection.

Yet the panel cautions that unintended consequences of SAI “could also affect stratospheric temperatures, circulation and ozone production, and destruction rates and transport.”

The hole in the ozone layer was first discovered by researchers at the University of California, Irvine (UCI) in the 1970s.

“Back then, chemistry professor F. Sherwood “Sherry” Rowland and postdoctoral student Mario Molina made a shocking discovery,” writes UCI News. “A single chlorine atom byproduct from aerosol hairsprays, deodorants, and other popular consumer products could chew up 100,000 ozone atoms in the stratosphere. The stratospheric ozone layer, 12 to 30 miles above Earth, protects life on the planet from harsh solar radiation.”