Question

Increased level of greenhouse gases causes global warming which will result in:
A. biomagnification
B. eutrophication
C. melting of glaciers
D. ozone depletion

Answer 1

Hint: Greenhouse effect may be defined as the phenomenon in which earth’s atmosphere traps heat from the sun and prevents it from escaping into outer space, thereby leading to increase in temperature to earth’s surface. Knowing the effect of greenhouse, we can answer the question.

Complete step by step answer:
Firstly, let us understand what greenhouse effect actually is.
- The earth receives a large amount of energy from the sun. Out of the total energy received, about 66% is absorbed by the earth while the rest 34% is reflected or scattered back into space. \[\text{C}{{\text{O}}_{\text{2}}}\] gas allows short wave radiations (visible, ultraviolet) of sun to pass through it but impedes the passage of long wave radiations (infrared, heat radiations). Thus, atmospheric \[\text{C}{{\text{O}}_{\text{2}}}\] acts as a barrier against the flow of heat from the earth to atmosphere. The reflected heat radiations would thus increase the temperature of the earth’s surface. This phenomenon is known as the greenhouse effect.
- During the entire 20th century, the average global temperature increased by about \[\text{0}\text{.}{{\text{6}}^{\text{o}}}\text{C}\]. The rise in temperature may lead to climatic changes. It may lead to rise in sea level due to the increased rate of melting glaciers.
The correct option is option “C” .

Note: Biomagnification is the accumulation of toxic chemicals in the tissues of organisms at higher levels of food chain.
- Eutrophication is a condition of lakes or reservoirs involving excess algal growth, caused due to inorganic pollutants like fertilizers, acids, salts and detergents in water.
- Ozone depletion is caused due to chemical compounds containing chlorine and fluorine, released by industries or other human activities.