Earth is a planet in a dynamic equilibrium that continuously absorbs and emits magnetic radiation. It receives ultra-violet and visible radiation from the sun and emits infra-red radiation. Thus, the energy that comes in must be equal to the energy that leaves. This is a vital factor that determines the average temperature of the earth. Some atmospheric gases like carbon dioxide and methane trap a major fraction of these radiations and increase the planet’s temperature.
This variation in temperature and its impact on our weather pattern is comprised under the term climate change. The terms climate change and global warming have come to our attention in a relatively short span and are now affecting our lives. It is one of the most serious problems that our world is facing.
The fundamental property of greenhouse gases is to absorb infra-red radiation. Carbon dioxide and methane currently contribute about 80% to the greenhouse effect. The most abundant primary greenhouse gas is water vapour. The other gases are nitrous oxide, ozone, chlorofluorocarbons, perfluorocarbons and hydrofluorocarbons. Whereas other gases like oxygen, nitrogen and argon are considered non-greenhouse gases.
Causes for Temperature Change
As we saw earlier, the emission of greenhouse gases leads to temperature change. But what causes the increase in greenhouse gases concentrations?
- Destroying carbon sinks by deforestation
- Gaseous emissions from vehicles
- Chlorofluorocarbons from refrigerators and air conditioners
- Farming activities
- Increase in population
There are some natural factors that can also have an effect on temperature change. The natural causes include forest fires, volcanoes, melting permafrost, etc.
The greenhouse gas ozone can technically be harmful or helpful depending on which layer of the atmosphere it is found. The ozone layer is a region present in the lower portion of Earth’s stratosphere. The ozone layer plays a vital role in absorbing ultraviolet radiation from the sun. If ozone is present in the troposphere layer, it can lead to climate change.
Furthermore, depletion or thinning of the stratospheric ozone layer can lead to a harmful environment as well as health defects. The free radicals like nitrous oxide, nitric oxide and compounds with gaseous chlorine or bromine cause the ozone layer depletion. Researchers have also found that unregulated rocket launches can also lead to the depletion of ozone. Some natural causes, such as stratospheric wind and sunspots, can also lead to the thinning of the ozone.
Ozone Depleting Substances
Many human-made chemicals play a major role in thinning of the ozone, which eventually leads to an ozone hole. Some of the ozone-depleting substances are –
- Methyl Chloroform
- Methyl Bromide
- Carbon tetrachloride
The above-mentioned components are used as foaming agents, refrigerants, industrial solvents, fumigants and also in air conditioners and other electrical equipment. Usually, the authorities belonging to environmental protection issue permits for the export or import of such ozone-depleting substances.
Montreal Protocol was conceived to protect the stratospheric ozone layer from depletion. It is a landmark multilateral agreement that regulates the consumption as well as production of nearly a hundred human-made ODS (ozone-depleting substances). It is the most widely implemented international climate agreement. This protocol has a major role in the recovery of the ozone hole above Antarctica.
The current national pledges and adaptations are not enough to achieve the set goals. Limiting greenhouse gas emissions and temperature change will require a greater pace of change from both urban and rural populations. Hence, individual efforts also play an important role along with national policies.
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