Tag: biology

Global warming is the increase in temperature of earth due to the increased concentration of greenhouse gases in the atmosphere. Temperature change due to global warming is faster than the temperature change due to natural climate fluctuations. This has resulted in melting of ice glaciers which will lead to rising in sea level and also the amount of freshwater will decline. Abnormal increase in temperature due to global warming has resulted in the extinction of many plant and animal species because of habitat loss and extreme climatic conditions.

The burning of fuels in the atmosphere leads to the formation of poisonous oxides and dioxides which push up the temperature of the earth and contributes to global warming. Clouds and gases reflect about one-fourth of the incoming solar radiation, and absorb some of it but almost half of incoming solar radiation falls on earth's surface heating it, while a small proportion is reflected back. Earth's surface re-emits heat in the form of infrared radiation but part of this does not escape into space as atmospheric gases (e.g., carbon dioxide, methane, etc.) absorb a major fraction of it. The molecules of these gases radiate heat energy, and a major part of which again comes to earth's surface, thus heating it up once again.The above-mentioned gases (carbon dioxide and methane) are commonly known as greenhouse gases because they are responsible for the greenhouse effect. 

Greenhouse effect increases the temperature of the earth.The gases responsible for greenhouse traps the infrared radiations which lead to heating of the earth's surface. The primary greenhouse gases in earth's atmosphere are water vapour, carbon dioxide, methane, nitrous oxide, and ozone. The 

• Greenhouse effect increases the temperature of the earth. The gases responsible for greenhouse traps the infrared radiations which lead to heating of the earth's surface. 
  
  
• The primary greenhouse gases in the earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone. 
  
  

When the solar radiation falls on earth surface heating it, a small proportion is reflected back. Earth's surface re-emits heat in the form of infrared radiation but part of this does not escape into space as atmospheric gases (e.g., carbon dioxide, methane, etc.) absorb a major fraction of it is called as greenhouse effects. The molecules of these gases absorb solar energy and increase the earth's temperature and these gases are called as greenhouse gases. Thus, the correct answer is option B.