Question

what is global warming and greenhouse effect

Answer 1

hey mate

it's your answer

the gradual increase in the average temperature of the earth is called global warming


the trapping of radiations by greenhouse gases causing warming of the earth is called greenhouse effect

Answer 2

Earth absorbs about 75 % of the total solar energy reaching its surface thereby increasing its temperature. Some of this energy is radiated back into the atmosphere. The gases present in the atmosphere for example ozone, methane, carbon dioxide, water vapor and chlorofluorocarbons are called greenhouse gases, they absorb some heat thereby restricting the heat to escape our atmosphere. These gases add to the heating of the atmosphere and result in global warming.

In places where the temperature is low, we use glass covered areas known as a greenhouse to grow flowers, fruits, and vegetables. It is very interesting to know that even we live in a greenhouse, but the difference is that we are not covered by the glass but by the blanket of air called the atmosphere. It is this atmosphere which has kept the earth’s temperature constant for centuries and helped in the survival of life. Atmosphere traps the heat around the earth and keeps it warm. This is called as natural greenhouse effect because it maintains the temperature and sustains life.

In a greenhouse, the solar energy enters through the glass, warms the soil and atmosphere and helps in the growth of plants. In return, the soil and plants emit infrared radiation, which is partly absorbed and partly reflected by the glass. This mechanism traps the sun’s energy in the greenhouse. Similarly, we have carbon dioxide which absorbs heat (as they are transparent to sunlight but not to infrared heat radiation) and is the major contributor to the global warming.

Other than carbon dioxide we have methane, ozone, CFC’s and nitrous oxides forming a major part of greenhouse gases. These chemicals either occur naturally or are man-made. The use of these compounds should be reduced; otherwise, the average temperature of the earth will rise. This will result in melting of polar ice caps and flooding of the coastal areas. Increase in the global temperature also increases the incidence of diseases like dengue, malaria, yellow fever etc.

Greenhouse Effect

To understand the nature of the greenhouse effect on climate change which leads to global warming, we must first know what the greenhouse effect is.

When you enter a car that has been in the sun for quite some time, what is the first thing you notice? It is a lot hotter inside than it is outside. The sun’s rays (UV radiation, thermal radiation, visible light) enter the car through the glass panes and all the rays entering the car do not leave owing to the buildup of gases inside the car and the refractive properties of the glass itself. The weaker thermal radiation does not completely leave the car. This eventually heats up the inside of the car.

The same thing happens in a greenhouse. The plants in a greenhouse require a warm temperature to grow. Have you ever seen a greenhouse? It is made almost entirely out of glass. The heat is retained and the plants thrive. The temperature inside a greenhouse is always higher than the temperature outside.