The UN-backed Scientific Assessment Panel to the Montreal Protocol on Ozone Depleting Substances quadrennial assessment report, published every four years, confirms the phase out of nearly 99% of banned ozone-depleting substances.
Key highlights of report
- The Montreal Protocol has thus succeeded in safeguarding the ozone layer, leading to notable recovery of the ozone layer in the upper stratosphere and decreased human exposure to harmful ultraviolet (UV) rays from the sun.
- 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.
- An additional 2016 agreement, known as the Kigali Amendment to the Montreal Protocol, requires phase down of production and consumption of many hydrofluorocarbons (HFCs).
- HFCs do not directly deplete ozone, but are powerful climate climate change gases.
- This amendment is estimated to avoid 0.3–0.5°C of warming by 2100 (this does not include contributions from HFC-23 emissions).
- 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 stratospheric aerosol injection (SAI) which is also a geoengineering.
- The panel cautions that unintended consequences of SAI “could also affect stratospheric temperatures, circulation and ozone production and destruction rates and transport.”
About Montreal Protocol
- 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 and it is one of the most successful global environmental agreements.
