September 11 to 25 is observed as Langban Heisoi Katpa or Tarpan, cultural legacy of the Meitei community in Manipur where victuals are offered to the departed souls. The Meiteis believe that if the departed souls are satisfied with the offering, then they bless and protect the people from evils. But, during this 15-day Tarpan, if we could plant at least one sapling each for the departed souls, it will be the greatest and most pleasing offering one could give to them – “protecting life on earth”, which is the theme for World Ozone Day 2022 on September 16.
World Ozone Day has been observed since 1987 and "Montreal Protocol@35: global cooperation protecting life on earth" is this year’s theme of the day. This theme recognises the wider impact that the ozone layer has made on climate change and forged partnerships to address global warming and protect life on earth.
The Montreal Protocol for the ozone layer is considered to be one of the most successful environmental agreements so far. The Protocol takes measures to control global production and consumption of substances that deplete ozone, with the ultimate objective of scientific knowledge and technological information.
The ozone layer, a fragile shield of gas, protects the earth from harmful ultraviolet rays of the Sun, thus helping to preserve life on the planet. The phase-out of controlled uses of ozone depleting substances, ODS and the related reductions have not only helped to protect the ozone layer for us and future generations, but have also contributed significantly to global efforts to address climate change to protect human health and ecosystems.
The COVID-19 vaccination has taught us the importance of refrigeration for vaccine preservation. Thus as to mitigate climate change, we will require ACs and refrigeration in future also. Hydrochlorofluorocarbons (HCFCs) are gases used worldwide in refrigeration, air-conditioning, foam applications, cleaning of electronic components and as solvents. These are both ODS and powerful greenhouse gases: the most commonly used HCFC is nearly 2,000 times more potent than CO2 in terms of its global warming potential. But, Hydro fluoro carbons (HFCs), were introduced as non-ozone depleting alternatives to support the timely phase out of CFCs and HCFCs. HFCs are now widespread in use but while these chemicals do not deplete the stratospheric ozone layer, they have high global warming potentials ranging from 12 to 14,000. Overall HFC emissions are growing at a rate of eight per cent per year and annual emissions are projected to rise to 7-19% of global CO2 emissions by 2050. Uncontrolled growth in HFC emissions therefore challenges efforts to keep the Paris Agreement for 2°C in this century.
Under the Convention’s Montreal Protocol, governments, scientists and industries have so far replaced 99 per cent of these gases. Thus, the ozone layer is now healing and safeguarding the ecosystem services. One of the good news or as an after effect from COVID-19 is the Antarctic ozone hole - one of the deepest, largest gaps in the ozone layer in the last 40 years - was much reduced, according to the World Meteorological Organization reported on January 6, 2021.
But, the work is not yet over. Through the Protocol’s Kigali Amendment, the international community is finding the alternatives for coolants that will replace HFCs to prevent 0.4°C of global warming. It is imperative to tackle climate change, protecting the natural ecosystems and forging a brighter and more equitable planet for humanity.
At an average, in 10 millions of air molecules, there is about two million oxygen and only three molecules are of ozone (O3). Although very small in quantity, it plays a vital role in our atmosphere. Ozone also occurs at the ground level which is injurious to health but not as harmful as the stratospheric ozone.
Earth’s atmosphere is divided into several layers. The lower region, known as the troposphere extends up to 10 km from the surface. Virtually, all the human activities occur in this region. The next layer is the stratosphere extending from 10 Km to 50 km. About 90% of the earth’s ozone is found in this region with maximum concentration occurring at the height of about 23.5 Km. Ozone at this region is formed when oxygen molecules absorb ultraviolet photons from Sunlight and undergo photolysis. These ozone molecules absorb ultraviolet rays (UV-B) of wavelength 314-280 nm, the most harmful radiation thereby preventing it from reaching the Earth’s surface.
The cause of 80 per cent stratospheric ozone depletion is due to the increase in the level of free radicals from HCFCs, CFCs. When CFCs break down, free chlorine, fluorine atoms are released. These atoms are so reactive that a single chlorine atom can destroy as many as 1 million ozone molecules. With this process, the ozone layer in the stratosphere is depleting day by day.
Due to ozone layer depletion and exposure to higher amounts of UV radiation could have serious impacts on all biotic forms on the planet. The challenges to human health include skin cancers, sunburns, premature aging of the skin, cataracts and other eye diseases and weak immune system.
Experts say, if not checked the problem of ozone layer depletion, 20 per cent of the world population may suffer from skin cancer in the next 50 years. Cataracts cause 50 per cent of 17 million blind cases in the world. A sustained 10 per cent thinning of the ozone layer is expected to cause two million new cataract cases every year. Ozone layer depletion and weakness in immune suppression in all the biotic forms is a hot topic of the present day.
Ozone layer depletion has also adverse impacts on agriculture, forestry and natural ecosystems. It can affect the important food crops by adversely affecting cyanobacteria which helps them to absorb and utilize nitrogen. World's major crop species, wheat, rice, barley, oats, corn, soybeans, peas, tomatoes and almost all staple and cash crops are particularly vulnerable to increase in UV radiation, resulting in reduced growth, size, photosynthesis and flowering time. Small changes in leaf size may increase the ability of weeds to grow and increase in the relative population of various unwanted species. Small changes in pollination time, resistance to insects or diseases, or in the length of the growing season, could cause great changes in yield challenging to our food security.
Phytoplankton, the tiny photosynthesizing sea plants that account for roughly half of the worldwide uptake of CO2 from the atmosphere and provide 70% of all the oxygen available on the earth, are genetically damaged by UV-rays. Coral Reefs that mankind termed them as the tropical forest of the ocean are also most affected by ozone layer depletion.
A decrease in the productivity of forests due to increased UV-rays would dramatically reduce the CO2 uptake by plants also that will not only reduce oxygen production but will contribute to global warming with attendant changes in cloud cover, precipitation patterns, temperatures, and so on, which would not spare the complexity of interdependence and consequences of ozone depletion on the biosphere.
UV-rays overexposure may cause eye and skin cancers to animals also. But animals with fur are somewhat saved from UV-radiation. Species of marine animals in their developmental stage e.g. young fish, shrimp and crab larvae are also widely threatened by the increased UV radiation under the ozone holes.
Materials such as wood, plastic, rubber, fabrics, paints and many other construction materials are degraded by UV radiation impacting the social economy. It is an undisputed fact that if we stop use and the production of HFCs and CFCs right now, then also, its problem will persist on earth for the next hundred years.
Therefore, with the coming of World Ozone Day during this month of Manipur’s Tarpan, let us take oath not to use ozone depleting substances, but to plant more trees to save the mother earth and the future generation with a healthier environment and a better economy.
(The views expressed are the writer's own)