Ecological Imbalances:

1. Green House Effect

The higher concentration of carbon dioxide may act as a serious pollutant. The carbon dioxide layer present in the atmosphere function like the glass panel of the green house which allow the sun light to pass through but prevent the heat from being re radiate in outer space. This is called green house effect or atmospheric effect.

Thus, increase carbon dioxide level tends to warm the air, which is called Global Warming. Bout 100 Years ago the concentration of CO2 was 275 ppm. Now it is 350ppm and by the year 2040, it is expected that it will reach to 450 ppm.

Causes of increase in CO₂:

Due to human civilization, excessive amount of CO₂ is being deposited in the atmosphere through furnaces  of power plants automobiles factories burning of coal or fossils fuels. To some extent on increase in CO₂ level in atmosphere increases the rate of photosynthesis but further increase pollutes the air and water. There are other gases also which cause green house effect they are CO SO₂, NO₂, CH₄, and CFCs

Effect of Global Warming

• Green house effect results global warming which causes more floods due to melt of ice and the sea level increases. More hurricanes and cyclones occur.
• If the total ice of earth melt then 200 ft of water would be added to the ocean surface.
• A rise in sea level of 50-100 cm would flood low lands of Bangladesh and West Bengal.
• Within 25 years, there will be rise in sea level by 1.3-3.5 m. Then only from Bangladesh alone 15 million people will have to move. Dhaka and Calcutta may be inundated.
• A rise of 50C temperature of earth raises the sea level by 5m within few decades.
• Higher atmospheric temperature would increase evaporation of water from the farms thus reduce the crop yield.

1. Depletion of Ozone Layer

The ozone is a gas (O3) occurs naturally in earths atmosphere between 10-50 Km. the ozone is considered as both destroyer as well as protector for us.

The ozone as a destroyer: High concentration of ozone reduces crop yield, damage leaves reduces quality of crops. 0.3-ppm ozone causes throat, nose irritation, 1.3 ppm causes fatigue, and 9 ppm causes several pulmonary diseases.

Ozone as protector: The ozone layer prevents UV rays coming from sun to the earth. 10% reduction of O3 increases UV radiation on the earth by 2%. It causes skin cancers. 10% reduction of ozone leads 20-30 % increase skin cancer. Only in America 6000 people per year die by skin cancer

What is Ozone?

The accumulation of oxygen in the atmosphere due to photosynthesis by green plants resulted in the formation of an ozone layer high in the earth atmosphere. The ozone layer forms a very protective covering around the earth's atmosphere. It prevents the UV rays present in the solar radiations from reaching our atmosphere, thus saving us from the extremely damaging effect of UV rays.

The Ozone layer depletion is the process of destruction or using up of ozone in the stratosphere by different pollutants making the ozone layer thinner. when ozone is depleted there would be certain zones or holes without ozone through which UV radiation enter the earth causing various problems such zone or hole called ozone hole.

Cause of Ozone depletion

Chlorofluorocarbon (CFC) and nitrogen oxides produced by the air craft, satellites, industries, and fertilizers release in atmosphere and specially CFCs stays for five to six years in the atmosphere. During this period, it gradually releases chlorine, which reacts with ozone and causes damage to it.

CFCs…………………..Cl + C-compounds

O₃ + Cl ClO + O²

ClO + O Cl + O₂

Effect of ozone layer depletion:

• Change of environment, due to more UV radiations entering in the earth rises to a certain degree, which can lead to the failure of rainfall.
• When the ozone layer is depleted, harmful UV radiations may cause skin cancers.
• A higher UV radiation reduces the photosynthesis, causes necrosis, leaf drop, the growth is altered, the chlorophyll content wills decrease, harmful mutation of plants, and animals, reduce the productivity of the crops, decrease in the number of phytoplankton and zooplankton, and harms fishes and other aquatic life.

2. Acid Rain

It is the process of deposition of acid gases from the atmosphere on land in the form of precipitation or rain. It thus increases H ions concentration of precipitation. In water whole the cocktail rain with H₂SO₄ and HNO₃ is called acid rain.

Causes of Acid Rain: Oxides of sulphur and nitrogen are the major air pollutants produced by the combustion of fossils fuels from power generation, industries, factories and automobiles.

Effects of Acid Rain

• Acid rain acidifies the soil Affects flora and fauna Affect human health Acidifies lakes and streams
• Affect aquatic animals and vegetation Reduces plant productivity
• Acid rain destroys forest Kills useful bacteria and blue green algae

In Sweden more than ten thousand lakes are acidic and in USA thousands of lakes are acidic and in Germany 8% forest was cleared by acid rain.

Control:

• Air pollution should be controlled
• A forestation should be dome
• Gases coming out of automobiles should be treated first before discharging out
• Alternative sources of energy should be used
• Catalyst process catalyst converter should be used to change toxic gases