Nick Webb investigates the science and research behind the encouraging news that part of our ozone layer is starting to heal, slowly.
Photo by Allan Scott McMillan | Location: Calgary, Canada
Research published last month from scientists at the University of Colorado Boulder is showing that the affects on the Ozone layer above Antarctica are starting to reverse and even heal.
At about an altitude of about 10 km (6.2 miles) it contains a high concentration of ozone, of which absorbs most of the ultraviolet radiation reaching the earth from the sun.
This is great news for Planet Earth, since the purpose of the ozone is to protect living organisms from the excessive UV radiation, increased exposure can interfere with the DNA and cell division processes in animals and humans leading to mutations, skin cancer, cataract in eyes, weakness in human immune response.
A depleted ozone layer could have a serious impact on plants, ecosystems, materials and biochemicals cycles. It's importance is critical to the balance of our world.
According to National Geographic: “The ozone layer is a thin part of the Earth's atmosphere that absorbs almost all of the sun's harmful ultraviolet light. "Ozone holes" are popular names for areas of amage to the ozone layer. "
The Research and Report
The report suggests that this is due to restrictions first put in place at the Montreal Protocol in 1987. It looks at how weather patterns seen from satellite imaging and simulations show a change in winds above Antarctica and how the changes are down to human actions rather than random climate fluctuations.
The hole was created as a result of the industrial usage of Ozone Depleting Substances, namely man-made gases, from the 1960s onwards. The opening of the hole caused air currents around the southern hemisphere to move further south, leading to the for the Hadley Cell jet stream - which is responsible for trade winds and tropical rains - to get wider.
Antara Banarjee, lead author of the paper said: “This study adds to the growing evidence showing the profound effectiveness of the Montreal Protocol. Not only has the treaty spurred healing of the ozone layer, it’s also driving recent changes in Southern Hemisphere air circulation patterns.”
In the study, Banarjee and her colleagues have shown that the trend of ozone depletion reversed from around the year 2000, as concentrations of ozone-depleting substances began to lessen, leading to a gradual recovery.
Using computer simulations to show the changes in circulation trends, the researchers determined that the pause in depletion could not only be caused by naturally shifting wind patterns. The statistics the research team gathered showed how even with rising CO2 emissions, the changes in near-surface circulation could only happen within the Ozone layer.
Towards the end of the 20th Century, the combination of rising emissions of CO2 and greenhouse gasses and diminishing amounts of ozone depleting substances in the atmosphere pushed near-surface circulation more towards the poles. Since the turn of the new millennium, the rising CO2 has balanced the effect of ozone recovery, continuing to push circulation poleward.
Long-Lasting Success on the Horizon
Martyn Chipperfield, from the University of Leeds has said that “we have turned the corner” in terms of ozone recovery, and that the study represents the next step in seeing what effects the recovery of the ozone layer could have on the global climate.
While we are starting to see the beginnings of recovery in the ozone layer, ozone depleting chemicals have a very long atmospheric life span, and different parts of the world will recover at different rates.
Banerjee suggests that in the Northern Hemisphere, ozone levels will return to the levels seen in the 1980s by the 2030s, but the Southern-mid latitudes will not recover until the 2050s, with the Antarctic hole not fully recovering until the 2060s. Chipperfield, however does predict climate change will thin the ozone layer around the tropics at the same time, which will have to be tackled.
John Fyfe, a co-author of the paper said “Identifying the ozone-driven pause in circulation trends in real-world observations confirms, for the first time, what the scientific ozone community has long predicted from theory.”
Banerjee says “We term this as a ‘pause’ because the poleward circulation trends might resume, stay flat, or reverse. It’s a tug of war between the opposing effects of ozone recovery and rising greenhouse gases that will determine future trends.” Essentially, we’re not out of the woods yet.
These results are showing how human efforts to combat negative effects of some forms of pollution are starting to have some success. While full recovery is some time away, it shows unified efforts across the globe do work, towards a better trend, that can benefit all.
We are a socio-ethical impact charity advocating for topics that matter, whilst supporting wider planetary change and acknowledgement. A charitable initiative funded by readers like you. | To support our work and journalism, consider becoming an advocate from just £1.