Question

Write a short note on greenhouse effect.

Answer 1

It is defined as a process of having a high temperature in the green house although it receives fewer radiations than the outside. It occurs due to the high concentration of carbon dioxide and vapor content. The glass walls are also included under it. They allow the short wave radiations to enter the house. There is almost no dissipation of energy as the longer heat waves cannot penetrate through the carbon dioxide and vapor. It leads to the warmer dust and cloudy nights as compared to the dry nights. The gas such as carbon dioxide is known as the green house gas as it is transparent to the solar radiations but have the ability to absorb infra red waves. These are also known as the long waves. The carbon dioxide concentration in the atmosphere has increased which may be attributed to the increase in the temperature of atmosphere. This effect is known as the green house effect. It melts the ice and increases the sea level.

Answer 2

Greenhouse Effect

A green house is a small house made up of glass that is used to grow plants . It traps the solar rays and keeps the heat fromescaping . It becomes warm inside the house . The glass traps the heat from radiating back to the space . The gass allows the light which comes from the sun to go through but blocks the light reflected by plants from giong out . This causes the heat to be retained in the green house .

Gases such as carbon dioxide , carbon monoxide , methane and water vapour present in the atmosphere also trap heat and are called greenhouse gases . The natural greenhouse gases act like a big blanket around the earth , keeping it warm and make life possible , without which temperature would have fallen to subzero values . This phenomenon of naturally warming up is called ' Greenhouse Effect ' | ( Fig . 5 . 51 ) . But the extent of this natural warming up the process has been grossly affected now .

Let us discuss these in detail .

The greenhouse effect refers to the change in the steady state temperature of a planet or moon by the presence of an atmosphere containing gas that absorbs and emits infrared radiation . Greenhouse gases , which include water vapor , carbon dioxide and methane , warm the atmosphere by efficiently absorbing thermal infrared radiation emitted by the earth ' s surface , by the atmosphere itself , and by clouds. As a result of its warmth , the atmosphere also radiates thermal infrared in all directions , including downward to the Earth ' s surface . Thus , greenhouse gases trap heat within the surface - troposphere system . The greenhouse effect is one of several factors that affect the temperature of the Earth .

Usually carbon dioxide is not considered as a pollutant , but in higher concentration , it forms a thick layer above the earth surface which checks the radiation of the heat from the earth surface . Because of this , the temperature of the earth surface increases . This is called as " Greenhouse effect ". The various greenhouse gases such as carbon dioxide ( CO_2 ) which gives 60 % of warming effect , methane ( CH_4 ) gives 20 % of warming effect , chlorofluorocarbon or CFCs gives 14 % of warming effect and Nitrous oxide ( N_2O ) gives 6 % of warming effect . Even 2 - 3°C rise in temperature will lead to melting of glaciers and ice caps of Polar Regions and consequently causes floods in rivers , rise in sea level and changes in cycle of rain . Islands may be submerged in sea water . If the present growth rate is continued , then the amount of carbon dioxide will be double by year 2020.