GLOBAL WARMING is not a separate entity. It is a highly complex phenomenon, which is directly or indirectly interlinked with various spheres of the Universe such as atmosphere (air), ozonosphere (ozone layer), biosphere (living beings), hydrosphere (water), lithosphere (land) etc. From a layman’s point of view, global warming is nothing but gradual increase in the Earth's surface temperature, which in turn causes a serious impact on the environment. According to environmental experts, Ozone layer depletion and surplus Greenhouse gases in the atmosphere are two major factors responsible for global warming.

Greenhouse gases and Greenhouse Effect

The Sun is the major source of energy, which sustains all life on the Earth. In the normal course, when the sunlight or radiation reaches the Earth's surface, some of them are absorbed by the Greenhouse gases such as Water vapor (H2O), Ozone (O3), Carbon dioxide (CO2), Methane (CH4), Nitrous oxide (N2O) and Chlorofluorocarbons (CFC’s) that are present in the atmosphere and the rest is radiated back to the atmosphere. However, certain long wavelength radiant energy which is being absorbed by these Greenhouse gases are not radiated back, which keeps the Earth’s atmosphere warm. Of the Greenhouse gases, CO2 is the major gas, which is responsible for global warming. The Greenhouse gases in the atmosphere including ozonosphere acts as a pan of glass, which allows the Sun’s short wavelength radiation and prevents some of the long wavelength radiation that are marching towards the Earth. Further, it prevents the heat being reradiated out of the Earth’s surface. This phenomenon is known as Greenhouse effect. While the greenhouse effect is an essential environmental prerequisite for life on Earth, when the greenhouse gases are added excessively into the atmosphere, this warms up the Earth’s surface and causes harmful effects to life on Earth.Ozone layer and its depletion

Ozone layer and its depletion

Ozone gas is one of the naturally occurring gases in the atmosphere. It is formed by three oxygen atoms. Ozone layer is otherwise known as Ozonosphere. The Ozone layer acts as a filter or shield in the atmosphere by absorbing harmful Ultraviolet (UV) radiation emitted by the Sun. The Ozone layer extends from a height of 20 km to 60 km above the Earth's surface.Recent studies show that there are holes in the Ozone layer and Ozone layer itself is depleting considerably day by day due to Ozone depleting substances such as Halon, Chlorofluorocarbons (CFCs), Carbon tetrachloride, Methyl chloroform, Methyl bromide, Hydrobromofluorocarbons (HBFCs), Hydrochlorofluorocarbons (HCFCs) and so on. The chlorine and bromine molecules of these substances react with the Ozone molecules and convert them into free oxygen atoms. The destruction of natural Ozone layer in the atmosphere is one of the root causes of global warming. Every year September 16 is observed as ‘World Ozone Day’ so as to create awareness among the common masses about the importance of Ozone layer, which protects our mother Earth from the harmful impacts of ultra-violet (UV) radiation emitted by the Sun.

Major causes and consequences of global warming

Though there are many things that are directly or indirectly contributing to global warming, the main reason for global warming is an excessive emission of Greenhouse gases in the Earth’s atmosphere by human activities viz., population explosion, deforestation, industrialization and rapid increase in usage of automobiles.

Carbon dioxide (CO2) is one of the major Greenhouse gases alarmingly released in the Earth’s atmosphere for the past few decades due to the above-mentioned human activities. Rise in CO2 concentration in the atmosphere is mainly due to the burning of fossil fuels such as coal, petrol, diesel, kerosene, gasoline etc, which is a major contributor to global warming. The other things, which contribute to global warming, are wood, cow dung, animal respiration etc.

Since global warming is a complex phenomenon, its full-scale impacts could not be predicted far in advance. Environmental Scientists warn that global warming may affect the blue planet, our Mother Earth with the following consequences. There will be changes in weather patterns, monsoons and seasons. It may cause heat waves and unusual warm weather, warming of oceans, melting of glaciers including the Arctic and Antarctic regions, leading to an abnormal rise in water levels in the seas and oceans, which will in turn cause flooding of coastal areas and low-lying areas. It will also cause heavy rainfall, heavy snowfalls, unexpected flooding, severe droughts, dramatic water shortages and natural forest fires. All these unusual things either directly or indirectly cause a wide range of impacts on flora and fauna including human beings.

According to a United Nations climatic report, the Himalayan glaciers, one of the major sources which provide water for river Ganga may disappear by 2030 due to constant rise in temperatures. In India, the Ganga provides fresh water for more than 500 million people for drinking and farming. If the global warming is not stopped, the Ganga eventually will become a seasonal river, largely dependent on monsoon rains.

How to prevent global warming?

We cannot prevent global warming at this juncture, but we can slow down its development and lessen its effects. If the Government takes serious steps to implement the following steps, we can combat global warming to a considerable level.

1. Minimising the use of Greenhouse gases producing units/agents

The Government of India is taking many precautionary measures to control Global warming which includes controlling of air pollution. To support the government decisions, as an individual, we should come forward to contribute to reduce Air pollution or Greenhouse gases in the atmosphere especially Carbon dioxide (CO2) gas in many ways. If we speak at the Indian context, we can avoid using crackers during festival times especially Diwali, public and political meetings. We should stop burning the old cloths and unwanted articles during festive seasons, Pongal and Makarasankranti etc.

2. Promoting of Non-conventional and Renewable energy sources

To minimise the extraordinary emission of Greenhouse gases in the atmosphere, which is the main root cause for the global warming, the Government should come forward to promote non-conventional and renewable energy sources such as solar energy, wind energy, tidal (wave) energy, hydro (water) power etc. to produce electricity for the use in agriculture, farms, factories and houses. These alternative sources do not produce air pollution and cause environmental problems. Wind energy can also be used to draw water from the ground in addition to the production of electricity.

The Central and State Governments should come forward to provide higher amount of subsidy to individuals, farmers, industrialists etc. to opt for non-conventional energy sources especially solar energy as an alternative to petroleum products, so that the Greenhouse gases in atmosphere can be reduced considerably, which will in turn control global warming. Since the solar radiation is striking the surface of the Earth more than our requirement, which can be very well utilised to meet our daily home needs, we can opt for solar energy sources to meet our daily needs such as cooking, heating, lighting or electrification, water pumping etc.

3. Streamlining deforestation

Deforestation (cutting of forest trees) would speed up the process of global warming. Only trees absorb CO2 from the atmosphere and release oxygen in return, which helps to create the optimum balance of gases in the atmosphere. Since more forest trees are cut down for timber, to make way for farming, to create human settlements etc. leading to the rise of CO2 in the atmosphere which cause to raise the temperature of the Earth’s surface, if at all, we cut one tree, we should try to plant at least 10 saplings of tree species to compensate the same.

4. Implementation of ‘One family, One tree’ policy

The Government of India is popularising the ‘One family, One tree’ policy/concept among the common public to create a healthy and greener India. Just by following this concept, we can also combat global warming. An ideal plant for this cause is Moringa oleifera Lamk., popularly known as ‘Drumstick’ (Hindi: Sajna, Sanjna, Sehjan), one of the important medicinal and economic plant of India. It is also regarded as one of the useful trees in the world. This plant is chiefly cultivated for its fruits and leaves. It has proven nutritive and medicinal values. The stem cuttings of this plant thrives well in tropical and semi-tropical climate and shows considerable growth within three months followed by flowering and fruiting in six months. So, let us plant the Drumstick plant in our houses for our personal benefits on one hand and on the other to reduce concentration of CO2 in the atmosphere to certain extent, which will in turn reduce global warming. Let us all follow the above-mentioned steps strictly to combat global warming, thereby to conserve the global biodiversity for survival and for posterity.