The molecules of carbon dioxide in the Earth’s atmosphere affect the h

Question

The molecules of carbon dioxide in the Earth’s atmosphere affect the heat balance of the Earth by acting as a one-way screen. Although these molecules allow radiation at visible wavelengths, where most of the energy of sunlight is concentrated, to pass through, they absorb some of the longer-wavelength, infrared emissions radiated from the Earth’s surface, radiation that would otherwise be transmitted back into space. For the Earth to maintain a constant average temperature, such emissions from the planet must balance incoming solar radiation. If there were no carbon dioxide in the atmosphere, heat would escape from the Earth much more easily. The surface temperature would be so much lower that the oceans might be a solid mass of ice.

Today, however, the potential problem is too much carbon dioxide. The burning of fossil fuels and the clearing of forests have increased atmospheric carbon dioxide by about 15 percent in the last hundred years, and we continue to add carbon dioxide to the atmosphere. Could the increase in carbon dioxide cause a global rise in average temperature, and could such a rise have serious consequences for human society? Mathematical models that allow us to calculate the rise in temperature as a function of the increase indicate that the answer is probably yes.

Under present conditions a temperature of-18℃ can be observed at an altitude of 5 to 6 kilometers above the Earth. Below this altitude (called the radiating level), the temperature increases by about 6℃ per kilometer approaching the Earth’s surface, where the average temperature is about 15℃. An increase in the amount of carbon dioxide means that there are more molecules of carbon dioxide to absorb infrared radiation. As the capacity of the atmosphere to absorb infrared radiation increases, the radiating level and the temperature of the surface must rise.

One mathematical model predicts that doubling the atmospheric carbon dioxide would raise the global mean surface temperature by 2.5℃. This model assumes that the atmosphere’s relative humidity remains constant and the temperature decreases with altitude at a rate of 6.5℃ per kilometer. The assumption of constant relative humidity is important, because water vapor in the atmosphere is another efficient absorber of radiation at infrared wavelengths. Because warm air can hold more moisture than cool air, the relative humidity will be constant only if the amount of water vapor in the atmosphere increases as the temperature rises. Therefore, more infrared radiation would be absorbed and reradiated back to the Earth’s surface. The resultant warming at the surface could be expected to melt snow and ice, reducing the Earth’s reflectivity. More solar radiation would then be absorbed, leading to a further increase in temperature.   1 
 1. The primary purpose of the passage is to

(A) warn of the dangers of continued burning of fossil fuels
(B) discuss the significance of increasing the amount of carbon dioxide in the atmosphere
(C) explain how a constant temperature is maintained on the Earth’s surface
(D) describe the ways in which various atmospheric and climatic conditions contribute to the Earth’s weather
(E) demonstrate the usefulness of mathematical models in predicting long-range climatic change

2 
 2. According to the passage, the greatest part of the solar energy that reaches the Earth is

(A) concentrated in the infrared spectrum
(B) concentrated at visible wavelengths
(C) absorbed by carbon dioxide molecules
(D) absorbed by atmospheric water vapor
(E) reflected back to space by snow and ice

3 
 3. According to the passage, atmospheric carbon dioxide performs all of the following functions EXCEPT:

(A) absorbing radiation at visible wavelengths
(B) absorbing infrared radiation
(C) absorbing outgoing radiation from the Earth
(D) helping to retain heat near the Earth’s surface
(E) helping to maintain a constant average temperature on the Earth’s surface

4 
 4. Which of the following best describes the author’s attitude toward the increasing amount of carbon dioxide in the atmosphere and its consequences?

(A) Incredulous
(B) Completely detached
(C) Interested but skeptical
(D) Angry yet resigned
(E) Objective yet concerned

5 
 5. It can be concluded from information contained in the passage that the average temperature at an altitude of 1 kilometer above the Earth is about

(A) 15℃
(B) 9℃
(C) 2.5℃
(D) -12℃
(E) -18℃

6 
 6. It can be inferred from the passage that the construction of the mathematical model mentioned in the passage involved the formulation of which of the following?

(A) An assumption that the amount of carbon dioxide added to the atmosphere would in reality steadily increase
(B) An assumption that human activities are the only agencies by which carbon dioxide is added to the atmosphere
(C) Assumptions about the social and political consequences of any curtailment of the use of fossil fuels
(D) Assumptions about the physical conditions that are likely to prevail during the period for which the model was made
(E) Assumptions about the differential behavior of carbon dioxide molecules at the various levels of temperature calculated in the model

7 
 7. According to the passage, which of the following is true of the last hundred years?

(A) Fossil fuels were burned for the first time.
(B) Greater amounts of land were cleared than at any time before.
(C) The average temperature at the Earth’s surface has become 2℃ cooler.
(D) The amount of carbon dioxide in the atmosphere has increased measurably.
(E) The amount of farmland worldwide has doubled.

RC Butler 2021  -  Practice Two RC Questions Everyday.   
Passage # 98 Date: 10-Mar-2021
 This question is a part of RC Butler 2021 .  Click here for Details

Gladiator59 · Accepted Answer

4 mins 12 secs to all correct but the last question. SajjadAhmad, I feel the OA to Q7 should be D. Please look into it.

Summary: The passage begins with talking about the importance of CO2 in the atmosphere and goes on to warn about the probable negative effects of growing CO2 over the last hundred years. It then details how mathematical models help predict the average temperature rise with growing CO2 and further adds that one of these models assumes constant humidity. Also, towards the end, a positive loop is described where rising temperature leads to the melting of polar ice caps and loss of reflectivity of earth leading to even higher heat capture and more temperature.

Need to focus on the main point of the passage and not on the details used to convey it.
1. The primary purpose of the passage is to
(A) warn of the dangers of continued burning of fossil fuels Again, fossil fuels is indirectly the cause of the direct material being discussed i.e CO2
(B) discuss the significance of increasing the amount of carbon dioxide in the atmosphere Perfect - this is the heart of the content.
(C) explain how a constant temperature is maintained on the Earth’s surface This is just a detail used to show the importance of CO2 in the first paragraph
(D) describe the ways in which various atmospheric and climatic conditions contribute to the Earth’s weather Earth's weather is out of context and too broad we are only looking to talk about CO2 and average temperature.
(E) demonstrate the usefulness of mathematical models in predicting long-range climatic change Again, not the main point but a means to an end.

Direct detail question from the passage
2. According to the passage, the greatest part of the solar energy that reaches the Earth is
(A) concentrated in the infrared spectrum
(B) concentrated at visible wavelengths Perfect - mentioned in the passage
(C) absorbed by carbon dioxide molecules
(D) absorbed by atmospheric water vapor
(E) reflected back to space by snow and ice

EXCEPT type - so we are looking for the one option that does not fit or is incorrect
3. According to the passage, atmospheric carbon dioxide performs all of the following functions EXCEPT:
(A) absorbing radiation at visible wavelengths Perfect - it is said to only absorb the infrared wavelength
(B) absorbing infrared radiation Given in the passage
(C) absorbing outgoing radiation from the EarthMentioned - again infrared only
(D) helping to retain heat near the Earth’s surface Given - this is what the passage talks about!
(E) helping to maintain a constant average temperature on the Earth’s surface This is the end point of CO2 heat capture as per the first paragraph

Author's tone is to be judged by the key words the author uses and also need to look at the end of each paragraph to search for them in addition to the end of the passage
4. Which of the following best describes the author’s attitude toward the increasing amount of carbon dioxide in the atmosphere and its consequences?
(A) Incredulous Not even close!
(B) Completely detached The author does not show to be detached, infact is actively researching and quoting models etc. Wrong.
(C) Interested but skeptical Author is definitely interested but does not show skepticism
(D) Angry yet resigned Laughably incorrect
(E) Objective yet concerned Perfect - objective as the author uses math models to express the content and concern for the probable negative impact of the increase of CO2 on Human life

Direct application question. QUITE UNIQUE! The passage mentions a drop of 6 deg per km from the surface and that the surface is at a mean of 15 deg
5. It can be concluded from information contained in the passage that the average temperature at an altitude of 1 kilometer above the Earth is about
(A) 15℃
(B) 9℃ CORRECT
(C) 2.5℃
(D) -12℃
(E) -18℃

The author takes quite some time to explain that the model assumes a constant humidity and then goes one step forward to explain what this assumption entails - so we need to definitely look out for this in the options.
6. It can be inferred from the passage that the construction of the mathematical model mentioned in the passage involved the formulation of which of the following?
(A) An assumption that the amount of carbon dioxide added to the atmosphere would in reality steadily increase Unrelated - the author was talking about twice the amount present curently - so steady increase is wrong - moreover this is the hypothesis of the model and not the assumption
(B) An assumption that human activities are the only agencies by which carbon dioxide is added to the atmosphere Out of scope of the math model
(C) Assumptions about the social and political consequences of any curtailment of the use of fossil fuels Way out of scope of the model
(D) Assumptions about the physical conditions that are likely to prevail during the period for which the model was made Perfect - mentioned in a esoteric way but "physical conditions" can rightly describe a physical concept of humidity. correct answer
(E) Assumptions about the differential behavior of carbon dioxide molecules at the various levels of temperature calculated in the model Never mentioned

OA should be D according to me. But currently given as B.
Detail question asked from directly mentioned information from the passage
7. According to the passage, which of the following is true of the last hundred years?
(A) Fossil fuels were burned for the first time. Again - this has not been mentioned. "For the first time" makes this option incorrect
(B) Greater amounts of land were cleared than at any time before. "Than any time before" is too extreme and not mentioned in the passage
(C) The average temperature at the Earth’s surface has become 2℃ cooler. Opposite of what is mentioned - the average temperature increased
(D) The amount of carbon dioxide in the atmosphere has increased measurably. Perfect - the passage talks about a 15% increase in the atmospheric CO2 - this is definitely a measurable jump
(E) The amount of farmland worldwide has doubled. Out of scope - not mentioned

Hope this helps.

icandy · Answer

Science Passage and EASY in the same sentence?? No kidding!

15.5 min

B B A E B D D

How ever I have a problem with answer choice B in 17

discuss the significance of increasing  the  amount of carbon dioxide in the atmosphere

"The" changes the whole meaning and sounds as if some one is increasing it intentionally.

It sounds as if lets increase the CO2 levels and we will see what happens.

nitya34 · Answer

Yes interesting and I found it V Easy The Theme of the Topic is so well known took 6 mins to read and another 5 mins to answer all 7 Qs BBEEBDD expecting at least 6/7 here

nitya34 · Answer

Icandy,
you are perfect
I misread the "red underlined part"

19. According to the passage, atmospheric carbon dioxide performs all of the following functions EXCEPT:

(A) absorbing radiation at visible wavelengths
(B) absorbing infrared radiation
(C) absorbing outgoing radiation from the Earth
(D) helping to retain heat near the Earth’s surface
(E) helping to maintain a constant average temperature on the Earth’s surface
The Passage says:
"Although these molecules   allow radiation at visible wavelengths  , where most of the energy of sunlight is concentrated, to pass through, they absorb some of the longer-wavelength, infrared emissions radiated from the Earth’s surface, radiation that would otherwise be transmitted back into space. "

VerbalBot · Answer

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The molecules of carbon dioxide in the Earth’s atmosphere affect the h

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The molecules of carbon dioxide in the Earth’s atmosphere affect the h

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