Environment

Ozone Layer to fully recover in decades - But ...

A UN-backed panel of experts, presenting at the American Meteorological Society’s annual meeting yesterday, said the ozone would heal 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 driven largely by meteorological conditions. Nevertheless, the Antarctic ozone hole has been slowly improving in area and depth since the year 2000.

However, so-called stratospheric aerosol injection (SAI) is increasingly seen as a potential stop-gap measure for capping temperatures long enough to tackle the problem of global warming at the source.

Scientists calculate that injecting 8 to 16 million tonnes of sulphur dioxide into the stratosphere each year, roughly equivalent to Pinatubo's output, would cool Earth's temperature by about 1C. Simulations over Antarctica in October - when the ozone hole is biggest - show that so-called stratospheric aerosol injection over 20 years would lower global temperatures by 0.5C.

But there's a trade-off: the ozone layer would be reduced to its 1990 levels, only a third of what it was before the impact of human activity.

Most dangerous would be the unforeseen consequences which may include the disruption of African and Asian monsoons, upon which hundreds of millions depend for food, to a drying of the Amazon, which is already transitioning toward a savannah state.

Once the sulphur particles have been introduced into nature, they cannot be removed if something goes wrong!