Increase in carbon dioxide in the atmosphere is caused by which of the following reasons?

I) Excessive use of fossil fuels

II) Deforestation

III) Increased number of vehicles

IV) Excessive use of solar heaters

Option 3 is the correct answer: Excessive use of fossil fuels, Deforestation, and an increased number of vehicles has to lead to an increase in amounts of carbon dioxide in the atmosphere.

Excessive use of fossil fuels:

• Carbon, Nitrogen, Hydrogen, Sulphur, and Oxygen are the primary constituents of most of the fossil fuels.
• Therefore after the burning of fossil fuels Sulphur oxides, Carbon mono and dioxide, Nitrogen oxides Volatile Organic Compounds, and Hydrocarbons are released into the air.
• Post industrialization period the use of fossil fuels has increased tremendously and so has the amounts of Carbon dioxide in the atmosphere.

Deforestation:

• Forests act as a sink for Carbon dioxide by taking them in and releasing oxygen.
• Due to deforestation, the forest area has decreased and the amount of CO₂ has therefore increased in the atmosphere.
• According to a study in journal Nature, around 46% of trees have been cut down since the process of deforestation was started.

Increased number of vehicles:

• Since most of the vehicles run on fossil fuels their excessive use also leads to an increase in amounts of CO₂.