According to a recent study (the first of its kind), there’s clear and decisive evidence that the hole in the ozone layer above Antarctica is beginning to close. Scientists measured the hole within the ozone layer back in September of 2015 and calculated at the time to be around 4 million sq. km smaller than it was in 2000, an area estimated to be the size of India.
Researches who worked on the study believe that the phasing out of certain manufactured air-born chemicals may be partly responsible for the dramatic shift, the study also sheds new light on the effects of erupting volcanoes may have on the ozone layer, ejecting lava, ash and gases into our atmosphere.
Historically, the natural ebb and flow of the ozone layer thinning and then renewing itself within the stratosphere balances itself out over long period’s time, protecting all life forms on Earth, by blocking out harmful ultraviolet radiation from the Sun.
British scientists first noticed a dramatic thinning of ozone in the stratosphere some 10 kilometers above Antarctica in the mid 1980s.
In the '80s, a giant hole in the ozone layer from CFCs endangered the planet. A new @PBS documentary explores how scientists including Susan Solomon of @MIT EAPS and world leaders worked together to prevent an environmental catastrophe. Watch: 4/10 @ 10pmhttps://t.co/xNI8T5YGrF pic.twitter.com/9wZ5D9kR0q— MIT EAPS (@eapsMIT) April 8, 2019
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US researcher Susan Solomon in 1986 discovered that the ozone layer was being eroded by the presence of harmful molecules containing chlorine and bromine within chlorofluorocarbons (CFCs). These same gases were found in numerous household goods including hairsprays, along with manufactured refrigerant products found in both refrigerators and air conditioning units.
Solomon’s research led to the formation by number of industrialized nations around the globe in September of 1987, to form an international treaty called the Montreal Protocol, in which numerous products containing CFCs known to deplete the ozone would be universally phased out of production. Today more than 197 countries have joined the alliance pledging to cut CFCs by more than 80% over the next 30 years.
Professor Solomon and along with several colleagues, including researchers from the University of Leeds in the UK, was also at the forefront of the recent study that chronicled the ozone layer’s resurgence.
Antara Banerjee, a lead author of the study told the Independent News network; “We found signs of climate changes in the southern hemisphere, specifically in the air circulation patterns. The challenge was showing that these changing air circulation patterns were due to the shrinking ozone hole following the implementation of the Montreal Protocol. The jet stream in the southern hemisphere was gradually shifting towards the South Pole in the last decades of the 20th century due to ozone depletion.
“Our study found that movement has stopped since 2000 and might even be reversing. The pause in movement began around the same time that the ozone hole started to recover. The emissions of ozone-depleting substances that were responsible for the ozone hole – the CFCs from spray cans and refrigerants started to decline around 2000, thanks to the Montreal Protocol.
“Overall, it is good news for the fight against climate change.” She added, “It shows that this international treaty has worked and we can reverse the damage that we’ve already done to our planet. That’s a lesson to us all.”
However, it’s also worth noting while much of the publicity was focused on spray cans and refrigerants in order to promote a certain political narrative. The study also noted the following.
“Volcanic eruptions affect polar ozone depletion because injections of sulfur increase the surface areas of liquid PSCs and aerosol particles. Higher-latitude eruptions directly influence the polar stratosphere, but tropical eruptions also can increase polar aerosols via transport. The model indicates that numerous moderate eruptions since about 2005 have affected polar ozone in both hemispheres, particularly at pressures from about 70 to 300 hPa. At pressures above about 100 hPa, temperatures are generally too warm for many PSCs to form, but there is sufficient water that effective heterogeneous chemistry can take place under cold polar conditions.”
“Our simulations indicate peak volcanic losses locally as large as 30 and 55% for the Antarctic in 2011 and 2015, mainly due to the Chilean eruptions of Puyehue-Cordón Caulle and Calbuco, respectively; contributions to depletions that are attributable to tropical eruptions are also evident in several earlier years. At these pressures, we’re the ones responsible for the study instrumental in the first of its kind study measuring carried out detailed measurements of the amount of ozone in the stratosphere between 2000 and 2015.”