Daily Current Affairs (MCQ) | Date 21.01.22

Q1. Which of the following is/are GreenHouse gases?

1. Carbon Dioxide (CO2)
2. Methane (CH4)
3. Nitrous Oxide (N2O)
4. Sulphur Hexafluoride (SF6)

Select the correct answer from the codes given below

a. 1 and 2 only
b. 1, 2 and 3
c. 2, 3 and 4
d. 1, 2, 3 and 4

Answer : d

Why is the Question ?

Greenhouse Gases
The four most common types of greenhouse gases are:
Carbon Dioxide (CO2): Carbon dioxide enters the atmosphere through the burning of fossil fuels (oil, natural gas, and coal), solid waste, trees and wood products, and as a result of other chemical reactions such as making cement.
Methane (CH4): Methane is emitted during the production and transport of coal, natural gas, and oil. Methane emissions also come from livestock and other agricultural practises and by the decay of organic waste in landfills.

Nitrous Oxide (N2O): Nitrous oxide is emitted during agricultural and industrial activities, as well as during the combustion of fossil fuels and solid waste.
Hydrofluorocarbons (HFCs), Perfluorocarbons (PFCs), and Sulphur Hexafluoride (SF6): These greenhouse gases combined make up only 3 % of all greenhouse gas emissions, but they are strong contributors to the greenhouse gas effect because they stay in the atmosphere for a very long time. These gases are used to keep things cool in our refrigerators and freezers as well as keep buildings and cars comfortable in hot weather. However, when the gases escape into the atmosphere, they trap the heat that comes from the sun and prevents it from escaping the atmosphere. 

Q2. Consider the following statements about Climate Change in the current age

1. It is the first event of Climate Change in earth’s geological history
2. It is largely because of Human activities

Which of the above statements is/are correct?

a. 1 only
b. 2 only
c. Both 1 and 2
d. Neither 1 nor 2

Answer : b

Why is the Question ?

As we all know, the earth has gone through warm and cool phases in the past, and long before humans were around. Forces that contribute to climate change include the sun’s intensity, volcanic eruptions, and changes in naturally occurring greenhouse gas concentrations. But records indicate that today’s climatic warming—particularly the warming since the mid-20th century—is occurring much faster than ever before and can’t be explained by natural causes alone. According to NASA, “These natural causes are still in play today, but their influence is too small or they occur too slowly to explain the rapid warming seen in recent decades.”

Q3. Consider the following statements

1. A complete absence of greenhouse gases in the earth’s atmosphere will make the earth more habitable for all life
2. Retreating glaciers in the Himalayan region will accelerate warming in the area

Which of the above statements is/are correct?

a. 1 only
b. 2 only

c. Both 1 and 2
d. Neither 1 nor 2

Answer : b

Why is the Question ?

The greenhouse effect is important because it contributes to the survival of life on Earth. Without the greenhouse effect, the temperature of the planet would be similar to conditions experienced on the moon. On the lunar surface, with no atmosphere to mediate temperature swings, the surface can reach 134 degrees Celsius (273 degrees Fahrenheit) during the day and - 153 degrees Celsius (-244 degrees Fahrenheit) at night. This dramatic temperature change required NASA to develop specialised gear to protect astronauts from both extremes for the moon landings. A similar temperature swing on Earth would have produced an environment hostile to most living things.
The widely distributed glaciers in the greater Himalayan region have generally experienced rapid shrinkage since the 1850s. The general albedo trend shows that the glaciers have been darkening since 2000. The most rapid decrease in the surface albedo has occurred in the glacial area above 6000 m, which implies that melting will likely extend to snow accumulation areas. Rapid loss of albedo due to retreating glaciers is causing higher levels of warming in the Himalayan region. 

Q4. Which of the following is/are the consequences of Climate change?

1. Changes in the global water cycle
2. Ocean acidification
3. Sea level rise
4. Increasing Glacial Lakes

Select the correct answer from the codes given below

a. 1 and 2 only
b. 1, 2 and 3
c. 2, 3 and 4
d. 1, 2, 3 and 4

Answer : d

Why is the Question ?

Climate change is causing five critical global environmental changes
1. Warming temperature of the earth’s surface and the oceans: The earth has warmed at a rate of 0.13° C per decade since 1957, almost twice as fast as its rate of warming during the previous century.
2. Changes in the global water cycle (‘hydrologic’ cycle): Over the past century there have been distinct geographical changes in total annual precipitation, with some areas experiencing severe and long-term drought and others experiencing increased annual precipitation. The frequency and intensity of storms increases as the atmosphere warms and is able to hold more water vapour 

3. Declining glaciers and snowpack: Across the globe, nearly all glaciers are decreasing in area, volume and mass. One billion people living in river watersheds fed by glaciers and snowmelt are thus impacted. Also declining ice cover is further leading to the warming of mountain areas like the Himalayas.
4. Sea level rise: Warmer water expands, so as oceans warm the increased volume of water is causing sea-level rise. Melting glaciers and snowpack also contribute to rising seas.
5. Ocean acidification: Oceans absorb about 25% of emitted CO2 from the atmosphere, leading to acidification of seawater. Extra carbon dioxide in the atmosphere is absorbed by the oceans, making them more acidic. This can make it difficult for corals and microorganisms that form shells to survive, disrupting the food supply for other sea animals.

Q5. Two fundamentally different approaches to the problem of global climate change have arisen. The first approach proposes the use of technologies that would increase the reflectance of incoming solar radiation, thus reducing the heating effect of sunlight on the Earth’s surface and lower atmosphere. The second geoengineering approach proposes to remove CO2 from the air and store it in areas where it cannot interact with Earth’s atmosphere. Which of the following can increase the reflectance of incoming solar radiation?

1. The injection of sulphur particles into the stratosphere
2. Large volcanic eruption
3. Cloud whitening
4. Orbital mirrors and sunshades

Select the correct answer from the codes given below

a. 1 and 2 only
b. 1, 2 and 3
c. 2, 3 and 4
d. 1, 2, 3 and 4

Answer : d

Why is the Question ?

Climate Engineering or Geoengineering, the large-scale manipulation of a specific process central to controlling Earth’s climate for the purpose of obtaining a specific benefit. Global climate is controlled by the amount of solar radiation received by Earth and also by the fate of this energy within the Earth system—that is, how much is absorbed by Earth’s surface and how much is reflected or reradiated back into space. The reflectance of solar radiation is controlled by several mechanisms, including Earth’s surface albedo and cloud coverage and the presence in the atmosphere of greenhouse gases such as carbon dioxide (CO2). If geoengineering proposals are to influence the global climate in any meaningful way, they must intentionally alter the relative influence of one of these controlling mechanisms.

Two fundamentally different approaches to the problem of global climate change have arisen. The first approach proposes the use of technologies that would increase the reflectance of incoming solar radiation, thus reducing the heating effect of sunlight on the Earth’s surface and lower atmosphere.
However, altering Earth’s heat budget by reflecting more sunlight back into space might offset rising temperatures but would do nothing to counter the rising concentration of CO2 in Earth’s atmosphere. The second geoengineering approach focuses on this problem, proposing to remove CO2 from the air and store it in areas where it cannot interact with Earth’s atmosphere. This approach is more appealing than the first because it has the potential to counteract both rising temperatures and rising carbon dioxide levels. In addition, reducing CO2 in the air could address the problem of ocean acidification.
To some scientists, global-scale geoengineering proposals border on science fiction. Geoengineering is also controversial because it aims to modify the global climate—a phenomenon that is not yet fully understood and cannot be altered without risk. Each proposal described below would differ from the others in its potential efficiency, complexity, cost, safety considerations, and unknown effects on the planet, and all of them should be thoroughly evaluated before being implemented. Despite this, no proposed scheme has been purposefully tested, even as a smallscale pilot study, and hence the efficiency, cost, safety, or timescale of any scheme has never been evaluated.

Proposals To Increase Solar Reflectance
Geoengineering schemes that could increase the reflectance of incoming solar radiation include the injection of sulphur particles into the stratosphere, the whitening of marine clouds, and the delivery of millions of tiny orbital mirrors or sunshades into space. It is important to note that a great deal of debate surrounds each of these schemes, and the feasibility of each one is difficult to ascertain. Clearly, their deployment at global scales would be difficult and expensive, and small-scale trials would reveal little about their potential effectiveness.

Stratospheric sulphur injection
The formation of an aerosol layer of sulphur in the stratosphere would increase the scattering of incoming solar radiation. As more radiation is scattered in the stratosphere by aerosols, less would be absorbed by the troposphere, the lower level of the atmosphere where weather primarily occurs. The 1991 eruption of Mount Pinatubo in the Philippines, often cited as the inspiration of this proposal, reported to have lowered average temperatures around the world by about 0.5 °C (0.9 °F) over the following few years.

Cloud whitening
The process of cloud whitening relies upon towering spraying devices placed on land and mounted on oceangoing vessels. Such devices would expel a mist of pressurised seawater droplets and dissolved salts to altitudes up to 300 metres (1,000 feet). As the water droplets evaporate, proponents believe, bright salt crystals would remain to reflect incoming solar radiation. Later these crystals would act as condensation nuclei and form new water droplets, which in turn would increase overall marine cloud coverage, reflecting even more incoming solar radiation into space.

Orbital mirrors and sunshades
This proposal involves the placement of several million small reflective objects beyond Earth’s atmosphere. It is thought that concentrated clusters of these objects could partially redirect or block incoming solar radiation. The premise is that as inbound solar radiation declines, there would be less energy available to heat Earth’s lower atmosphere. Thus, average global air temperatures would fall.