#25 - Oceanographer: To substantially reduce the amount of

[Administrator]

Please post below with any questions!

[dtodaizzle]

I got this one right through POE. But what does (C) mean exactly?

[Emily Haney-Caron]

Hi dotdaizzle,

Basically, C is saying, "the carbon dioxide pumped into the water won't just end up in the atmosphere again (because it won't end up dissolving into the atmosphere a long time before the cold deep water it was pumped into mixes with the warmer water on the surface)." With that explanation, I'd really encourage you to look back at the question and work through it again, seeing if you end up at C - and if not, try to reason through it. Struggling with why you got questions wrong or didn't understand them is a critical part of the learning process! And as you do that, definitely let us know if you end up with more questions on this one.

[tayloramalkin]

C is the best answer choice, but what type of reasoning is in this stimulus?
I thought that the conclusion contained causality. (Unless this isn't the conclusion)
Con=CO2 pumped into ocean-->reduce the amt of CO2 in atmosphere.

But then the support looks like it is conditional reasoning.
P1: CO2 pumped into ocean-->trapped for centuries

What is the best way to attack this type of problem?

[Emily Haney-Caron]

Hi tayloramalkin,

Good question! This question doesn't really use full conditional reasoning or full cause and effect; both are hinted at in the ways you described, but neither is sort of full-fledged enough to play a significant role in this question.

[arr0418]

What makes choice B incorrect? My thinking was that if war water near the surface released large amounts of carbon dioxide, then pumping carbon dioxide deep into the oceans wouldn't substantially reduce the amount of carbon dioxide in the atmosphere. Does it have to do with the fact that we can't determine the meaning of "large amounts of carbon dioxide" released from warm water relative to the "substantial" reduction indicated in the stimulus?

[AthenaDalton]

Hi arr 0418,

Answer choice (B) discusses evaporation rates of warm water close to the surface. However, the idea the oceanographer proposes is concerned primarily with cold water deep below the warm surface layer of the ocean.

The oceanographer's idea involves injecting CO2 deep into the ocean where it would mix with cold, dense water and stay trapped down there for centuries. Presumably, the CO2 would stay with the cold water near the ocean floor and well away from the warm water on the ocean's surface which evaporates. Since the experiment hinges on keeping the CO2 far away from the warm evaporating layer of water, we're not really concerned with what happens when the warm water evaporates (at least not for the next several centuries).

I hope that makes sense. Good luck studying!

Athena Dalton

[jw190]

Hello everyone,

Although I picked C originally, I've been stuck reviewing this question for some time now and just cannot figure out specifically why (E) is wrong.

The author is proposing a temporary fix to Earth's carbon issue; she wants to pump it into the deep ocean where it'll stay for hundreds of years. The assumption comes from her intermediate conclusion: that the C02 will stay stuck with the cool, deep water and will not quickly return to the surface.

(E) turns the problem into a conditional (which seems dubious), but one that seems to address this issue. "If C02 should be pumped into the deep ocean [which the author claims it should], then C02 must be trapped down there for 100s of years." Alternatively, "If C02 would not be trapped for 100s of years, C02 should not be pumped into the deep ocean." This choice seems to address that same assumption.

Also, negating (E) doesn't seem to help clear things up for me either. Negating the contrapositive, "If C02 would not be trapped for 100s of years, C02 should be pumped into the deep ocean." This still seems to hurt the argument!

Does anyone see what I'm not? Thanks for any advice!

[jw190]

Hello everyone,

Although I picked C originally, I've been stuck reviewing this question for some time now and just cannot figure out specifically why (E) is wrong.

The author is proposing a temporary fix to Earth's carbon issue; she wants to pump it into the deep ocean where it'll stay for hundreds of years. The assumption comes from her intermediate conclusion: that the C02 will stay stuck with the cool, deep water and will not quickly return to the surface.

(E) turns the problem into a conditional (which seems dubious), but one that seems to address this issue. "If C02 should be pumped into the deep ocean [which the author claims it should], then C02 must be trapped down there for 100s of years." Alternatively, "If C02 would not be trapped for 100s of years, C02 should not be pumped into the deep ocean." This choice seems to address that same assumption.

Also, negating (E) doesn't seem to help clear things up for me either. Negating the contrapositive, "If C02 would not be trapped for 100s of years, C02 should be pumped into the deep ocean." This still seems to hurt the argument!

Does anyone see what I'm not? Thanks for any advice!

My apologies for the double post. I've done some thinking on this one over the past couple days and wanted to add in my additional thoughts on why (E) is incorrect.

We're looking for the required assumption; the assumption that doesn't necessarily make her argument true, but at least makes it possible. This assumption is that the C02 won't escape quickly back into the atmosphere as, if it did, her recommendation wouldn't really help reduce Earth's C02 at all. (C) gets at this assumption perfectly.

With (E), I considered the contrapositive: "If C02 would NOT be trapped for 100s of years, C02 should NOT be pumped into the deep ocean." Does this conditional statement get at that same assumption? Not really. Although she is assuming the C02 won't quickly return to the surface, even if it did, would that be sufficient for her to abandon her recommendation? Maybe, maybe not. But either way it doesn't seem to be the assumption that's absolutely required.

How is my analysis of choice (E)? What am I missing and what can I improve? Thanks for reading!

[Adam Tyson]

Hey there jw, let me see if I can help. When using the Negation Technique on an answer choice that contains conditional reasoning, the negation of that answer will tell you that the necessary condition is not, in fact, necessary. Here, in answer E, the sufficient condition is "we should pump CO2 into the deep ocean to reduce it in the atmosphere"; the necessary condition is "it would be trapped for hundreds of years." The negation would tell us that it is not necessary for it to be trapped for hundreds of years: "We should do it even if it won't trap it for hundreds of years." Does "we should do it even if it won't trap it" wreck the claim that we should do it? Not at all! That's why we can reject answer E. Also, more to the point, we reject it because answer C is better, and we are charged with selecting the best answer!

Please let us know if you need further clarification. Meanwhile, try that "even if it's not necessary" approach on negating conditional statements, and you should find it pretty powerful and useful.

Good luck!