#12 - Climatologist: Over the coming century, winter

[Administrator]

Complete Question Explanation

Strengthen—CE. The correct answer choice is (B)

The climatologist’s argument has multiple causal relationships that connect together easily. The argument begins with the premise that global warming will lead to increased winter temperatures in the Rocky Mountains over the coming century:


GW = global warming
IWT = increased winter temperatures in the Rocky Mountains

Cause Effect

GW IWT


Next, we are told that the increased winter temperatures will lead to more of the precipitation falling as rain, rather than as snow:


IR = increased proportion of precipitation falling as rain

IWT IR


From this evidence, the climatologist concludes that the “mountain snowpack will probably melt more rapidly and earlier in the season,” which will cause there to be more spring flooding and less storable water available to meet summer demands:


SMMR = mountain snowpack melt more rapidly and earlier in the season
SF = more spring flooding
LSW = less storable water

SF

SMMR +

LSW


While it is clear that the author’s conclusion is causal, there is a link missing in the causal chain between the increased proportion of precipitation falling as rain (IR) and the snowpack melting more rapidly and earlier in the season (SMMR).

The question stem identifies this as a Strengthen question. Our prephrase is that the correct answer choice will likely provide the missing causal link described above, between the terms IR and SMMR, which would then make the argument, all together:

SF

GW IWT IR SMMR +

LSW


Answer choice (A): While attractive, this answer choice is incorrect, because the premises established the causal role of global warming, which is to shift the proportion of precipitation, resulting in more of it falling as rain, rather than as snow. Certainly, it appears that more precipitation in combination with the shift in the proportion of it falling as rain would have an effect on the melting of the snowpacks. However, this information supports a premise, not the conclusion.

Answer choice (B): This is the correct answer choice, because it establishes a causal connection between the melting of snowpacks, greater spring flooding, and a decrease in the amount of storable water. Interestingly, it does so by skipping over the intervening cause, i.e., increasing rainfall (IR), to connect directly with the issue of the snow packs melting more rapidly (SMMR). Although the strength of this answer choice is lessened by the fact that it deals with the melting of snowpacks in mountainous regions other than the Rocky Mountains, it still supports the conclusion to some degree by analogy.

Answer choice (C): This answer choice offers a correlation between relatively mild winters and less storable water, but does not establish a causal relationship between the two.

Answer choice (D): As with answer choice (C), this answer provides only a correlation, and not evidence of a causal relationship.

Answer choice (E): The size of the snowpack is not the issue. Rather, the argument focused on the relationship between the temperature in the region, the proportion of precipitation that falls as rain, and the melting of the snowpack.

[Arindom]

Hi,

Here, the conclusion is that melting of the snowpacks will cause greater spring flooding and less storable water to meet summer demands.

Could we rule out ans choices C and D because in the case of C - relatively mid winter doesn't mean that snowpacks have melted and in turn cause spring flooding and led to less storable water? There could be areas where there is hardly snow and meting would not cause flooding. Similar reasoning for D - we don't know whether the spring flooding is from mountain snowpacks melting- it could be some other reason. Is my analysis correct?

Thanks.

- Arindom

[BethRibet]

Hi Arindom,

Thanks for the question.

Yes, you're on the right track. To strengthen this argument, we need information that supports a relationship between the cause (melting snowpacks), and the effects (greater flooding, less storable water). Since C & D don't engage the cause, they are not good answers.

Hope this helps!
Beth

[lsat2016]

Hello,

I just wanted to ask a quick question - I was a bit wary about B because it talks about “other mountains regions” and not specifically about the Rocky Mountains that the premise talks about. I am usually vary wary of answer choices that do not accurately match the specific wording of the text. Doesn't this answer choice slightly raise the possibility that this phenomena may indeed happen in other mountainous regions and not specifically in the Rockies? When is it okay to assume that information about "other mountainous regions" can also apply to the Rockies specifically?

Thank you!!

[Ladan Soleimani]

Hello Lsat2016,

While you are right to be wary about language that doesn't quite match up, it is not an issue in this case. We are only looking for an answer choice that strengthens the author's conclusion, even by a little bit. You don't have to make the argument valid. An example from another mountain range does make it more likely that the author is correct and the Rocky Mountain snowpack will melt and lead to greater flooding and less storage, even though the mountain ranges may be different.

Ladan

[lsat2016]

Hello,

Can you explain why “increased winter temperatures” is not the “cause”, but rather, “melting snowpacks?

[Emily Haney-Caron]

Hi lsat2016,

This is a chain of causal relationships: global warming causes increased winter temps, increased winter temps causes more rain, more rain causes snowpacks melting more rapidly, and snowpacks melting more rapidly causes greater flooding + less storable water. Does that help?

[lsat2016]

Hello,

That’s what I was thinking! That’s also why I didn’t understand BethRibet’s response that C&D don’t engage the cause since C mentions “winters being relatively mild” and D “in the regions of the world with the mildest winters”.

global warming -> INCREASED WINTER TEMPS (MILD WINTERS) -> more rain -> more snowpacks melting -> less storable water.

Thank you!

[bli2016]

Hi, I still don't understand the gap in the logic of the stimulus. I thought the word "therefore" in the stimulus established a causal relationship with between the greater proportion of precipitation falling as rain and snowpacks melting more rapidly already, so I really did not know what to look for when I got to the answer choices. Could someone explain how to recognize that the connection between the greater proportion of precipitation falling as rain and snowpacks melting more rapidly is missing? Thank you!

[Francis O'Rourke]

Hi Bli,

It sounds like there are two issues at play here. The first issue is the use of the word therefore. When a speaker uses the word therefore or a similar word such as thus, so, hence, etc... the speaker is signalling to us that she believes the following conclusion can be drawn from the information provided.

These conclusion indicators do not tell us that the statement correctly follows logically from the premises, but rather that the speaker believes that it does. Merely writing the word thus does not immediately make the connection objectively correct, in fact it is at this point that you should ask yourself if the speaker did offer a valid argument.

In this case, there is a step in the argument that the speaker skipped. Recognizing that a step or a connection is missing is often hard by design on the LSAT. This is one instance where you can easily miss the gap in the reasoning, since the terms are so often associated with each other. We often hear about seasonal weather changes and lack of storable water so the conclusion might seem commonsense, especially if you live in the Western US.

Now let's look at it more carefully. As pointed out above, the speaker informed us that winter temperatures are likely to increase and that this increase is likely to bring about more rain and less snow. The speaker then signals to us that, based on those facts, she believes that there will be an earlier and more rapid melting of snowpack.

So why should we believe that? Personally, I don't have any idea what the consequences of more rainfall are for snowpack. It seems likely that less snowfall will mean less snowpack, but why would the snowpack melt more rapidly if there is less of it? Is there going to be icepack instead of snowpack? And why would the snowpack begin to melt earlier if we have no information on temperature change during spring and summer?

This sort of question is one that you may gloss over and not recognize since news reports so frequently connect 'global warming' or 'climate change' to droughts and flooding. Anytime I read a stimulus that brings in newsworthy content or loaded terms, I have to set myself on higher alert to watch out for assumptions that I make in day-to-day life. Since I tend to believe scientists who warn of climate change, I know that I have to slow down a little on this one, be more critical of the speaker's reasoning, and abstract the argument to neutral terms, such as IWT, IR, & SMMR as the diagram above does.