Increase in the concentration of carbon dioxide in the air is one of the major causes of global warming.
When the solar radiation fall on the earth’s surface, a part of the radiation is absorbed and a part is reflected back into the space. Green house gases like carbon dioxide and methane present in the atmosphere absorb some of the radiated heat. These trapped radiations further warm the earth. The trapping of the sun’s radiation by the gases present in the earth’s atmosphere is called greenhouse effect. Without the natural greenhouse effect, life would not have been possible on the earth because in the absence of such an effect, the earth’s surface would have been too cold to sustain life.
But for scientists the cause of worry is the increase in the amount of greenhouse gases beyond a safe limit. When the concentration of greenhouse gases increases in the atmosphere, they trap more heat. As a result, the earth’s temperature increases leading to the global warming. Thus, global warming can be defined as the increase in the average temperature of the earth’s atmosphere that causes corresponding changes in the climate.
The causes of global warming are:
- Burning of fossil fuels.
- Biological degradation of the organic matter present in sewage which release methane gas.
EFFECTS OF GLOBAL WARMING
Due to the greenhouse effect, the earth’s average temperature has raised 10C in the last 50 years. Scientists have predicted that if the concentration of the greenhouse gases keeps on increasing and the temperature of earth’s surface increases by 3-60C, the polar ice caps and the glaciers will melt. The enormous quantity of water thus produced will raise the sea level and will cause destruction all around. Some of the effects of global warming are:
- Increase in the earth’s surface temperature.
- Melting of glaciers and polar ice caps.
- Rise in the sea level will lead to flooding of low lying areas.
The oxides of sulphur and nitrogen present in the air react with the water vapour and form sulphuric and nitric acids. These acids come down with the rain making the rain water significantly acidic. Such rain is known as the acid rain.
The main cause of erosion of the marble of the Taj Mahal is the acid rain
EFFECTS OF THE ACID RAIN
Acid rain is quite corrosive and affects both living and the non living things adversely as:
- Acid rain slowly erodes the cement, limestone and marble of the buildings, corrodes steel and other metals too.
- It destroys vegetation due to acidification of soil and accelerates leaching.
- It acidifies the water of lakes and ponds and affects the survival of aquatic plants and animals.
Q.1. Green house gases are:
- Carbon dioxide
Q.2. In acid rain, which acids are formed:
- Nitric acid
- Sulphuric acid
Q.3. Global warming is related to which radiations:
- Infra red
- Ultra violet
Q.4. Which among the following is not the cause of the global warming:
- Burning of the fossil fuels
- Planting the trees
Q.5. Global warming leads to:
- Increase in the temperature of the earth
- Decrease in the temperature of the earth
- No change
- Both a and b