Question

Which of the following gas is responsible for 'Global-Warming'?
(a) Methane
(b) Ozone
(c) Carbon-dioxide
(d) Nitrogen

Answer 1

Hint: Many variables affect global temperatures, including the reflection of solar radiation by cloud cover, minor changes in the Sun’s intensity, airborne particulate matter from volcanic activity and sulphate aerosol.

Complete answer:
Carbon-dioxide is responsible for 'Global-Warming’.
A layer of ${ CO }_{ 2 }$ in the atmosphere traps the infrared radiation coming from earth's surface. These trapped radiations heat the earth's atmosphere and result in greenhouse effect and global warming.
The relative contribution of various greenhouse gases to total global warming is as follows:
${ CO }_{ 2 }=60\%$
${CH}_{4} =20\%$
$CFC =14\%$
${ N }_{ 2 }O=6\%$

Additional information:
Global temperature is on the rise, an effect known as global warming. A trend that coincides with the observed rise in greenhouse gases and the strong correlation between temperature and greenhouse gases from the past is impressive. When respiration predominates (during late fall through spring), ${ CO }_{ 2 }$ levels rise; when photosynthesis predominates (during late spring through early fall), ${ CO }_{ 2 }$ levels fall. As of early 2001, atmospheric ${ CO }_{ 2 }$ levels were over 370ppm, 35% higher than they were before the Industrial Revolution. The phenomenon has been observed since pre-industrial period (between 1850 and 1900).
So, the correct answer is ‘Carbon-dioxide’.

Note:
- Several other gases absorb infrared radiation and add to the insulating effect of ${ CO }_{ 2 }$.
- Warming will seriously affect rainfall and agriculture. The present-day difference between temperatures at the poles and those at the equator is a major driving force for atmospheric circulation.
- Climate change can not be stopped but it can be slowed.