Ozone Layer

Ozone Layer over Antarctica on track to recovery, thanks to concerted international action against ozone! A success story that should encourage action on climate.     Image © NASA/Ozone Hole Watch

The Earth’s protective ozone layer is well on track to recovery, according to a new assessment by 300 scientists.



Actions taken under the Montreal Protocol led to decreases in the atmospheric abundance of controlled substances, mitigating climate change and enabling the projected return of the ozone layer to the 1980 levels.

It’s on the road to recovery “an achievement that scientists say is due to political will.”

Ozone Layer over the years

NASA animation by Robert Simmon.

According to the study published by the UN Environment Programme (UNEP):

 

Model results suggest that global stratospheric ozone depletion due to ODSs did occur prior to 1980.
The midlatitude EESC was about 570 ppt in 1960 and nearly 1150 ppt by 1980.
The 1980 baseline for ozone recovery was chosen, as in the past Assessments, based upon the onset of adiscernible decline in observed global total column ozone. Between 1960 and 1980, the depletion was not large enough to be clearly distinguishable
from the year-to-year variability, especially given the sparsity of observations. If the 1960 value were chosen as the baseline, the EESC would return to that value well after 2100.



Ozone Layer

Variation in EESC at midlatitudes between 1960 and 2100. The future EESC is for the baseline scenario (described in the text before Highlight 1-1). Bottom panel: The average total column ozone changes over the same period, from multiple model simulations (see Chapter 2), are shown as a solid gray line. This is compared with the observed column ozone changes between 1965 and 2013 (blue line), the period for which observations are available.

via io9

source UNEP