Greenhouse Effect and Climate Change part 1

31. Which one of the following gases is both harmful and beneficial to life on earth? [U.P. Lower Sub. (Mains) 2013]

(a) Oxygen
(b) Ozone
(c) Nitrogen
(d) Carbon dioxide

Correct Answer: (d) Carbon dioxide

Solution:Plants use carbon dioxide to produce carbohydrates (sugars and starches) in the process known as photosynthesis. Since humans and all other animals depend on plants for their food, photosynthesis is necessary for the survival of all life on Earth. It is also a greenhouse gas which is very harmful to us. Therefore carbon dioxide is both useful as well as harmful to life on earth.

Carbon dioxide is a meteorologically important gas as it is transparent to the incoming solar radiation but opaque to the outgoing terrestrial radiation. Carbon dioxide absorbs some of terrestrial radiation and reflects some part towards the earth's surface. Carbon dioxide is largely responsible for the greenhouse effect. Its concentration is closer to the earth's surface as it is denser than air.

32. Which of the following statements best describes "carbon Fertilization"? [I.A.S. (Pre) 2018]

(a) Increased plant growth due to increased concentration of carbon dioxide in the atmosphere.
(b) Increased temperature of Earth due to increased concentration of carbon dioxide in the atmosphere.
(c) Increased acidity of oceans as a result of increased concentration of carbon dioxide in the atmosphere.
(d) Adaptation of all living beings on Earth to the climate change brought about by the increased concentration of carbon dioxide in the atmosphere.

Correct Answer: (a) Increased plant growth due to increased concentration of carbon dioxide in the atmosphere.

Solution:The carbon fertilization effect suggests that the increase of carbon dioxide in the atmosphere increases the rate of photo- synthesis in plants. The effect varies depending on the plant species, the temperature and the availability of water and nutrients. From a quarter to half of Earth's vegetated lands has shown significant greening over the last 35 years (1982-2015) largely due to rising levels of atmospheric carbon dioxide.

33. Which of the following are the primary causes of climate change? [U.P.P.C.S. (Pre) 2017]

1. Excessive burning of fossil fuels.
2. Exploding number of automobiles driven by oil
3. Increasing solar flares
4. Heavy deforestation

Select the correct answer using codes given below :
Codes :

(a) 2 and 3 only
(b) 1, 2 and 4 only
(c) 1, 2, 3 and 4
(d) 1 and 4 only

Correct Answer: (b) 1, 2 and 4 only

Solution:There are two primary causes of climate change- factors that increase carbon emission and factors that increase carbon absorption. The causes of increase in carbon emission include excessive burning of the fossil fuels, exploding numbers of automobiles driven by oil etc., while the carbon absorption rate is declining due to excessive deforestation. Therefore, Carbon concentrations are increasing in the atmosphere which is affecting the climate by increasing the greenhouse effect. NASA and other studies do not consider the solar flare as a major cause of climate change. Thus, option (b) is correct.

34. Consider the following : [I.A.S. (Pre) 2019]

1. Carbon monoxide
2. Methane
3. Ozone
4. Sulphur dioxide

Which of the above are released into atmosphere due to the burning of crop/biomass residue?

(a) 1 and 2 only
(b) 2, 3 and 4 only
(c) 1 and 4 only
(d) 1, 2, 3 and 4

Correct Answer: (d) 1, 2, 3 and 4

Solution:After Harvesting the leftover crop residues are disposed for land clearing and pest control. The cheapest and easiest method to dispose these crop/biomass residues is to burn it. However, burning of these crop/biomass residues release Carbon monoxide (CO), Sulphur dioxide (SO₂), Methane (CH) and Ozone (O₂) like gases in atmosphere. Hence option 3 (d) is correct answer.

35. Which among the following gases is most responsible for global Warming? [Uttarakhand P.C.S. (Pre) 2012]

(a) Nitrogen
(b) Methane
(c) Carbon-di-oxide
(d) Carbon mono-oxide

Correct Answer: (c) Carbon-di-oxide

Solution:Greenhouse gases in the environment are water vapour, Carbon Dioxide, Methane, Nitrous oxide and Clorofluoro Carbon. Among these, carbon dioxide is most responsible for global warming as its concentration in the environment is more as compared to other greenhouse gases. Notably, the concentration of carbon dioxide is increasing in the atmosphere.

36. Global Warming is caused due to the emission of : [U.P.P.C.S. (Mains) 2004]

(a) Nitrogen
(b) Carbon Dioxide
(c) Carbon Monoxide
(d) Hydro carbon

Correct Answer: (b) Carbon Dioxide

Solution:Global warming is primarily a problem of too much carbon dioxide in the atmosphere. This carbon overload is caused mainly when we burn fossil fuels like coal, oil and gas or cut down and burn forests. The presence of carbon dioxide in the atmosphere was about 315 PPM (Parts per million) in 1950. Currently, it has crossed 415 PPM. If the increase of carbon dioxide continues in the atmosphere at this speed, it will reach approximately 650-950 PPM by the end of the 21st century. This can raise the earth's temperature by 6°C.

37. The apprehension of Global Warming is aggravated by increased concentration, in the atmosphere, of - [U.P.P.C.S. (Spl) (Mains) 2008, 2004, (Pre) 2006]

(a) Carbon dioxide
(b) Nitrous oxide
(c) Ozone
(d) Sulphur dioxide

Correct Answer: (a) Carbon dioxide

Solution:Global warming is primarily a problem of too much carbon dioxide in the atmosphere. This carbon overload is caused mainly when we burn fossil fuels like coal, oil and gas or cut down and burn forests. The presence of carbon dioxide in the atmosphere was about 315 PPM (Parts per million) in 1950. Currently, it has crossed 415 PPM. If the increase of carbon dioxide continues in the atmosphere at this speed, it will reach approximately 650-950 PPM by the end of the 21st century. This can raise the earth's temperature by 6°C.

38. "Global Warming " is due to : [U.P. Lower Sub. (Mains) 2013]

(a) Heavy rainfall
(b) Increase in carbon dioxide
(c) Decrease in Carbon Dioxide
(d) Increase in forestation

Correct Answer: (b) Increase in carbon dioxide

Solution:Global warming is primarily a problem of too much carbon dioxide in the atmosphere. This carbon overload is caused mainly when we burn fossil fuels like coal, oil and gas or cut down and burn forests. The presence of carbon dioxide in the atmosphere was about 315 PPM (Parts per million) in 1950. Currently, it has crossed 415 PPM. If the increase of carbon dioxide continues in the atmosphere at this speed, it will reach approximately 650-950 PPM by the end of the 21st century. This can raise the earth's temperature by 6°C.

39. Which of the following is considered to be the optimum Concentration of Carbon-Dioxide for Natural balance In atmosphere? [U.P.P.C.S. (Pre) 2017]

(a) 0.02 percent
(b) 0.03 percent
(c) 0.04 percent
(d) 0.05 percent

Correct Answer: (b) 0.03 percent

Solution:Carbon dioxide gas is confined to troposphere only. Normally It forms about 0.03 percent by volume of the atmosphere. It is a colourless gas having a faint sharp odour and a sour taste. It is an important heat-trapping gas, also known as a greenhouse gas. It comes from the extraction and burning of fossil fuels (such as coal, oil, and natural gas), from wildfires, and natural processes like volcanic eruptions. It is one of the most important greenhouse gas (GHG) in the atmosphere and is the primary driver of anthropogenic climate change.

The presence of the gas in the atmosphere keeps some of the radiant energy received by Earth from being returned to space, thus producing the so-called greenhouse effect. Carbon dioxide is used as a refrigerant, in fire extinguishers, for inflating life rafts and life jackets, blasting coal, foaming rubber and plastics, promoting the growth of plants in greenhouses, immobilizing animals before slaughter, and in carbonated beverages.

40. Consider the following [I.A.S. (Pre) 2008]

1. Rice field
2. Coal mining
3. Domestic animals
4. Wetlands

Which of the above is a source of methane, a major greenhouse gas?

(a) 1 and 4
(b) 2 and 3
(c) 1, 2 and 3
(d) 1, 2, 3 and 4