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705-805 (Hard)|   Science|   Short Passage|                     
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AjiteshArun

I am still not clear how is B any different from D
AjiteshArun

Look at it this way (I'm assuming numbers):

1. Global warming was expected (predicted by models) to be (say) 5°.
2. Actual warming observed was only (say) 2° (less than what the models predicted).
3. The disparity between predicted and actual temperature increases was 3° (5 - 2)°.

4. In the early 1990s, Michaels thought that this difference was attributable to sulfate emissions, which had a temporary cooling effect. That was the reason that the actual figure (2°) was less than the predicted figure (5°).
5. He later had doubts about this explanation, because (a) most sulfate is emitted in the Northern Hemisphere and (b) after 1987, warming in the Southern Hemisphere ceased while warming in the Northern Hemisphere increased.

The question is asking us what Michaels would have been likely to agree with in the early 1990s about the disparity mentioned in lines 3-4. The disparity mentioned in those lines is the difference between predicted and actual temperature increases.

Option A: This disparity is relatively less extreme in the Northern Hemisphere because of sulfate cooling.
Michaels did not ever think that the disparity between the predictions by the models and actual warming was less extreme in the Northern Hemisphere. In fact, we have no idea about what the models predicted for the Northern and Southern Hemispheres (separately).

Option B: This disparity is only a short-term phenomenon brought about by sulfate cooling.
This is exactly what the passage says (Michaels sought to explain this disparity, suggesting that sulfate emissions in industrial areas had a cooling effect, thus temporarily retarding global warming).

Option D: The extent of this disparity is being masked by the temporary effect of sulfate cooling.
"The extent of this disparity is masked" means that the actual disparity was greater than what was seen ("masked" means "hidden"). That is, the actual disparity was greater than (5 - 2 = 3)°. Let's say the actual disparity was 4°. That is not what Michaels thought. Michaels said that the reason that the disparity was 3° was sulfate emissions. That is, if sulfate emissions had not been present, the disparity would have been smaller, not greater, because actual global warming would have been closer to what the models predicted.
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Hi,

Let me try to help break it down:
Relevant sentence from the passage: "In the early 1990s, Pat Michaels sought to explain this disparity, suggesting that sulfate emissions in industrial areas had a cooling effect, thus temporarily retarding global warming."

B) matches Michaels early view:
  • Models are basically fine
  • Sulfate cooling is temporarily slowing warming
  • Once sulfate effects fade, the disparity should disappear

D) on the other hand:
For D to be true, the passage would need to suggest that the real disparity is larger, and that sulfate cooling is hiding part of it. However this is not true and instead sulfates are introduced to explain why the disparity exists at all, not to hide a deeper one.

Hope this helps! :)
rak08
AjiteshArun

I am still not clear how is B any different from D

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AjiteshArun

I am still not clear how is B any different from D
Hi rak08,

Sure. Let's say you tried to predict the Indian team's score in a match. Your prediction was that they'd score 240 (X), but the actual score was 190 (Y). What's the disparity between your prediction and the actual? It's 50 (X - Y). Let's call this disparity Δ.

Michaels wanted to explain Δ. That's like "what is the reason for Δ?". In the team example, we could say that something like a batting collapse or exceptional fielding by the other team was the reason or explanation for the disparity.

Option D says The extent of this disparity is being masked by the temporary effect of sulfate cooling. This means that we aren't able to see the true extent of the disparity. In our example, that'd mean that Δ is not 50. Let's say (X - Y) is somehow greater than 50. But that can only happen if your prediction was greater than 240, or the actual score was less than 190 (or both). This is not what Michaels is trying to imply about the model's prediction or about the actual increase in temperature.
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so option D is unclear of the gap vs option B has a clarity on the gap
AjiteshArun

Hi rak08,

Sure. Let's say you tried to predict the Indian team's score in a match. Your prediction was that they'd score 240 (X), but the actual score was 190 (Y). What's the disparity between your prediction and the actual? It's 50 (X - Y). Let's call this disparity Δ.

Michaels wanted to explain Δ. That's like "what is the reason for Δ?". In the team example, we could say that something like a batting collapse or exceptional fielding by the other team was the reason or explanation for the disparity.

Option D says The extent of this disparity is being masked by the temporary effect of sulfate cooling. This means that we aren't able to see the true extent of the disparity. In our example, that'd mean that Δ is not 50. Let's say (X - Y) is somehow greater than 50. But that can only happen if your prediction was greater than 240, or the actual score was less than 190 (or both). This is not what Michaels is trying to imply about the model's prediction or about the actual increase in temperature.
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rak08
so option D is unclear of the gap vs option B has a clarity on the gap
That's right. Option D tells us that the gap is different from (most likely larger than) what the passage says.
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Boil it down:
· Scientists puzzled by disparity
· Author agrees that seemingly, disparity exists
· PM tried to explain, later doubted his idea. Evidence
· PM also doubted the models itself.
· Michaels’s claim that model predictions and observed data differ fundamentally
· Author: silent

· BS disagrees with PM doubting the models, “global warming models themselves may be flawed”
· BS says oceans in southern hemisphere slows down warming.
· BS agrees with sulphate cooling is complicating situation and playing some role.
· BS provides explanation pre-1987 after 1987.
· Author: Santer disputes Michaels’s claim that model predictions and observed data differ fundamentally

Why the author wrote the passage? Author admits a disparity. 2 clashing explanations. Author silent.

1. The passage suggests that, in the early 1990s, Michaels would have been most likely to agree with which of the following statements about the disparity mentioned in lines (Highlighted)?
A. This disparity is relatively less extreme in the Northern Hemisphere because of sulfate cooling – wrong – PM must have felt that the disparity was more extreme in Northern hemisphere
B. This disparity is only a short-term phenomenon brought about by sulfate cooling – correct – “suggesting that sulfate emissions in industrial areas had a cooling effect, thus temporarily retarding global warming”
C. This disparity is most significant in those parts of the world dominated by oceans.- wrong – PM was not much concerned by oceans. It was BS – anyway, PM must have felt that disparity should be less intense in southern hemisphere
D. The extent of this disparity is being masked by the temporary effect of sulfate cooling – wrong – PM should have agreed that sulfate cooling caused the disparity
E. The disparity confirms that current models of global warming are correct – wrong – current models are not discussed.


2. According to the passage, Santer asserts which of the following about global warming?
A. It will become a more serious problem in the Southern Hemisphere than in the Northern Hemisphere in spite of the cooling influence of oceans in the south – wrong – as per BS, north be warmer
B. It is unlikely to be a serious problem in the future because of the pervasive effect of sulfate cooling – irrelevant – not discussed at all
C. It will proceed at the same general rate in the Northern and Southern Hemispheres once the temporary influence of sulfate cooling comes to an end- hold on – but what about oceans slowing down global warming ?
D. Until the late 1980s, it was moderated in the Northern Hemisphere by the effect of sulfate cooling. – seems good – hold on – “sulphate cooling, which peaked in the north in the mid-twentieth century. It drastically slowed warming in the Northern Hemisphere, and warming in the Southern Hemisphere raced ahead. Since 1987, Santer argues, the greenhouse effect has reasserted itself, and the north has taken the lead”
E. Largely because of the cooling influence of oceans, it has had no discernible impact on the Southern Hemisphere. – wrong – “warming in the Southern Hemisphere raced ahead”


3. The passage suggests that Santer and Michaels would be most likely to DISAGREE over which of the following issues?
A. Whether climatological data invalidates global warming models – correct – “Santer disputes Michaels’s claim that model predictions and observed data differ fundamentally.”
B. Whether warming in the Northern Hemisphere has intensified since 1987 – wrong – both agree over it
C. Whether disparities between global warming models and climatological data can be detected – hold on – TRAP – it says whether disparities can be detected or not – both PM and BS agree that disparity can be detected.
D. Whether landmasses warm more rapidly than oceans – irrelevant – PM did not give thoughts over it
E. Whether oceans have a significant effect on global climate patterns – irrelevant – PM did not give thoughts over it
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