2020-05-14
| Prof. Ho Kin-Chung, Polar Researcher, Scientist & Expeditioner
In early May this year, scientists who have monitored the level of ozone depletion in the southern hemisphere announced a good news: the 'ozone hole' over the South Pole shrank to the smallest it’s been in 30 years! Just two weeks before, researchers also reported that the largest hole ever observed in the ozone layer over the Arctic has closed.
The ozone layer shields the Earth from most of the ultraviolet radiation, which is a major cause of skin cancer. While the ozone hole which is formed at the Stratosphere at Arctic this year was an irregular one, mainly attributed to the extremely powerful polar vortex and low temperature in part of the Northern hemisphere.
Extensive use of chlorofluorocarbon (CFC) products has long been harmful to the ozone layer at the top of Antarctica during the past 50 years. No matter how, human activities and uncontrolled pollutant discharge are the main reason of climate change and environmental degradation.
CFCs had been used since the 1930s as refrigerants and in aerosol sprays. They were consumed in an elevated amount since the World War II and, with lifetimes up to 100 years. At a ground level, they were nonreactive, nontoxic and nonflammable even when they escaped during parts of the production process. However, CFCs, once were spreading to the sky of Antarctica, they catalyse ozone destruction quickly in the exteremly low temperature environment at stratosphere there.
According to long-term trends from the data collected, the hole over Antarctica grew from 1980 through the early 1990s before stabilising in the early 21st century.
During the 1980s to 1990s, 30 to 40% of ozone lost at the Stratosphere was over southern Australia and New Zealand. After enactment of the Montreal Protocol, an environmental agreement ratified in 1987 by the United Nations that regulates the production and consumption of CFCs (which are almost 100 man-made chemicals) , the ozone hole so called has gradually recovered.
Photo source: Gazette & Essex County Standard
However, the long lifetime of the destructive chemicals has caused them to be an enduring problem. Scientists expected that the holes will take 60-80 years to be totally disappeared if current degenerating trend continued.
Comparatively, ozone depletion phenomenon rarely happened at the Arctic Stratosphere due to different temperature and climatic reasons. The first time an ozone hole was observed at the North Pole was in 2011, but it was smaller than that of this year and happened only in January.
The larger and long-durated ozone hole this year might attribute to the historically warm winter in Europe this year that triggered the strong polar vortex.
Interestingly, recent recovery is nothing related to the Covid-19 although the plague has resulted with stopping of most industrial and commercial activities in Europe, N. America and SE Asia. It is only due to the natural change in seasonal climate. However, human impacts that cause rapid climate change during the past decades should not be overlooked.
Photo source: K.C. Ho
Ironically, Earth Day (22nd April) this year happened in the midst of Covid-19 events. The World Environment Day (June 5th) is coming soon but the adverse impacts of cornavirus are likely to be continued.
While everybody is in our hibernation during the Covid-19, it is essential we take a break to rethink and reflect on how to care for our Mother Earth in a more sustainable manner like the way we show love and gratitude for our parents on Mother’s Day.
My annual scientific expeditions to Arctic and Antarctic remind me how fragile and vulnerable humans are. It is worrying for me to witness climate change happening in the polar region up close. It is disturbing for me to hear the denials of climate risks. It is heart breaking to note that past lessons were not learnt from the Ozone hole depletion nor the previous SARs outbreak.
Photo source: K.C. Ho
Every new red tide toxin strain discovered on my annual polar research expeditions is a clear wake up call that we should act before it is too late.
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