Why Is the Earth’s Ozone Layer Under Threat Again?

The Sun's ultraviolet rays are blocked by the ozone layer from damaging the Earth. (Screenshot/YouTube
The Sun's ultraviolet rays are blocked by the ozone layer from damaging the Earth. (Screenshot/YouTube

The ozone is under a new threat as chemicals not controlled by the United Nations treaty to prevent ozone depletion are on the rise. The study’s report shows that “very short lived substances” (VSLS) are rapidly growing in the atmosphere.

“VSLS can have both natural and industrial sources. Industrial production of VSLS is not controlled by the United Nations Montreal Protocol because historically these chemicals have contributed little to ozone depletion,” said study lead author Dr Ryan Hossaini, from the School of Earth and Environment at the University of Leeds.

The following video is about NASA scientists tracking down the source of ozone depleting chemicals, and studying their effects on the ozone layer.

“But we have identified now that one of these chemicals is increasing rapidly, and if this increase is allowed to continue, it could offset some of the benefits to the Ozone Layer provided by the Montreal Protocol,” said Hossaini.

To determine how VSLS impact on the ozone and climate, researchers use a 3D computer model of the atmosphere. Measurements of VSLS were also provided by the National Oceanic and Atmospheric Administration (NOAA)

The measurements showed that there was a rapid increase of concentrations of dichloromethane, which is a man-made VSLS used in a wide range of industrial processes.

“We need to continue monitoring the atmospheric abundance of these gases and determine their sources,” said study co-author Professor Martyn Chipperfield, from Leeds’ School of Earth and Environment.

“Due to their short atmospheric lifetimes, VSLS break down and destroy ozone in the lowermost part of the stratosphere. This is important, as a molecule of ozone lost in this region has a far larger impact on climate than a molecule destroyed at higher altitudes by longer-lived gases,” said Hossaini.

This NASA Goddard model runs from the year 1974 to 2064, and compares projected concentrations of ozone based on current emissions.

Naturally emitted VSLS account for around 90 per cent of the current overall loss of ozone, but the impact from man-made VSLS is increasing.

If we don’t start looking for solutions to this ozone depletion now, we may leave it until it’s too late.

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