On Ozone Day 2015, Antarctic Ozone Hole remains steady
Wednesday, September 16, 2015, 5:36 PM - This article originally appeared on October 31, 2014, and for today - September 16, 2015, International Day for the Preservation of the Ozone Layer - it has been updated to reflect the condition of the Antarctic ozone hole in 2015.
Reports from NASA and NOAA in late 2014 showed that the Antarctic Ozone Hole holds steady, providing some hope that this is a sign of recovery for Earth's protective ozone layer. However, even this cautious optimism may be spoiled by climate change.
Although the state of the ozone hole in October 2014 showed that it was around the same size as North America (24.1 million square kilometers), there is still some cautious optimism about the ozone layer, based on the trend seen in the past 10 years or so. As shown in the video above, the alarming growth of the ozone hole (and decline of ozone thickness, as seen in the graph) during the 1980s and 1990s painted a very grim view of the future.
Here's what the Antarctic ozone hole looked like on September 9, 2000, when it reached its largest expanse on record - 29.9 million square kilometers.
These two images show the status of the ozone hole on September 11 (left) and September 13 (right) of 2014, just as the hole was reaching its maximum extent for the year.
This was its status as of September 30, 2014. Although the shape has certainly changed (as the hole tends to rotate along with the southern polar vortex), it is roughly the same size.
According to NASA's Ozone Hole Watch website, the hole had been shrinking through the month of October, and it continued to do so through the southern spring and summer. Tracking the progress of it over a full year shows that it never truly closes, though. It fills in as the ozone depleting chemicals are 'used up', but it really just breaks apart to form several smaller holes surrounding Antarctica, until it reforms into the single gaping hole sometime in August.
According to NASA, there's some hope that the recent trend is showing some recovery, especially since measurements from the ground and space show that ozone-depleting chemicals are declining. However, as with many things involving Earth's atmosphere, it may not be that simple, since global warming is causing stratospheric temperatures to rise.
"Year-to-year weather variability significantly impacts Antarctica ozone because warmer stratospheric temperatures can reduce ozone depletion," said Paul A. Newman, chief scientist for atmospheres at NASA's Goddard Space Flight Center, according to a NASA statement. "The ozone hole area is smaller than what we saw in the late-1990s and early 2000s, and we know that chlorine levels are decreasing. However, we are still uncertain about whether a long-term Antarctic stratospheric temperature warming might be reducing this ozone depletion."
Status as of September 2015
As of September 13, 2015 - the latest record - the Antarctic ozone hole measured some 25.08 million square kilometres in area - 10,000 sq km shy of what it was on this day, just one year ago.
According to the UN:
In 1994, the UN General Assembly proclaimed 16 September the International Day for the Preservation of the Ozone Layer, commemorating the date of the signing, in 1987, of the Montreal Protocol on Substances that Deplete the Ozone Layer (resolution 49/114).
States were invited to devote the Day to promote activities in accordance with the objectives of the Protocol and its amendments. The ozone layer, a fragile shield of gas, protects the Earth from the harmful portion of the rays of the sun, thus helping preserve life on the planet.
The phaseout of controlled uses of ozone depleting substances and the related reductions have not only helped protect the ozone layer for this and future generations, but have also contributed significantly to global efforts to address climate change; furthermore, it has protected human health and ecosystems by limiting the harmful ultraviolet radiation from reaching the earth.
This year marks the 30th anniversary of the Vienna Convention for the Protection of the Ozone Layer, an important milestone in the protection of the ozone layer. The theme for the celebration of the anniversary and this year’s International Day for the Preservation of the Ozone Layer to be marked on 16 September is, "30 years of healing the ozone together." The theme is supported by the slogan, "Ozone: All there is between you and UV."