Question

If there was no CO$_2$ in the earth’s atmosphere, the temperature of earth’s surface
would be?
A. Same as present
B. Less than the present
C. Higher than the present
D. Dependent on the amount of oxygen in the atmosphere

Answer 1

Hint: Increase in the temperature of earth with time has been reported. Carbon dioxide and air pollutants present in the air traps the solar energy being radiated back by the surface of earth, leading to global warming.

Complete answer:
Over the geological time scale, the greenhouse gases concentration, specifically the methane and carbon dioxide have been found to fluctuate naturally. Moreover, human activities like burning of fossil fuels, use of transportation which are gasoline based and clearance of forest have contributed to changes in the concentration of gases in the atmosphere.
Various industrial effluents have increased the level of carbon dioxide in the atmosphere which further combines with the air pollutants present in the atmosphere. This traps the solar energy and raises the temperature of earth’s surface. This is also referred to as global warming. So, in the absence of carbon dioxide, global warming declines and the temperature of the earth thus decreases.
Thus, the right option is B.

Note: Global warming is recognized as a steady increase in the atmospheric gases, say methane, chlorofluorocarbons (also known as Freons or CFCs), nitrous oxides and methane which are added in the atmosphere via human activities. These gases are in common known as the greenhouse gases.