Self-study
Oceanographer: Conclusion To substantially reduce the amount of carbon dioxide in Earth's atmosphere, carbon dioxide should be captured and pumped deep into the oceans, where it would dissolve. ███ █████ █████ █████ ██ █████ ██████ █████ █████████ ██ ███ ████ ███ ██████ █████ ████ ███ ████████ ██ ███ ██████ ███████ ██████ ████ ████ ██████ █████ ██ ███████ █████ ███ ██████████
Summary
If we want to reduce carbon dioxide in the atmosphere, we should pump it deep into the ocean. Why? Cold, deep water takes a long time to mix with warm, surface water, and this ensures that the carbon dioxide would be trapped for a long time.
Notable Assumptions
In her reasoning, the oceanographer has made the mixing of cold and warm water necessary to release carbon dioxide. But what if it isn’t, and carbon dioxide can be released whether the water mixes or not? We need to know that this mixing is necessary for carbon dioxide release.
25.
Which one of the following ██ ██ ██████████ ████ ███ ███████████████ ████████ █████████
a
Carbon dioxide will ████████ ████ ████ ██████████ ██ ██ ██ ██████ ████ ████ █████ ████ ██ ████ ██ ██ ██ ██████ ████ ██████ ██████
Irrelevant. We were already told that the carbon dioxide will be pumped into cold water.
b
Evaporation of warmer █████ █████ ████ ██ ███████ ███████ ████ ███ █████████ ███████ ████ ███ ██████████ █████ ███████ ██ ███ ██████ ███████ █████████ ██ ███ ███████████ ██████
The oceanographer isn’t saying that the carbon dioxide will never escape, only that it will take centuries. If it is released after that point, the argument is unharmed. Also, if warm water releases carbon dioxide other than the carbon dioxide that was pumped into cold water, while the cold-water carbon dioxide remains trapped, the argument is also unharmed.
c
Carbon dioxide dissolved ██ █████ █████ █████ ██ █████ ██████ ████ ███ ██████ ████ ████ ███████ ██████████ █ ████ ████ ██████ ███ █████ ██ █████ ████ ██████ ███████ ██ █████████ █████ ████ ██████ █████ ████ ███ ████████
This must be true, and it matches our prediction. (C) is making the mixing of cold and warm water necessary for carbon dioxide release. If this is not true, and carbon dioxide can escape whether the water mixes or not, the argument has no support.
d
It is the ███████ ██ ███ █████ ██ ███ █████ ██████ ████ █████ ███ ████ ████ ██ ███ ████████ ██ ███ ██████ ████████
It doesn’t matter how the trapping happens. Additionally, (D) doesn’t specify in what way density is related to trapping: Is higher density or lower density preferred? We don’t know, and we can’t assume.
e
Carbon dioxide should ██ ██████ ████ █████ ██████ ██ ██████ ███ ██████ ██ ██████ ███████ ██ ███ ██████████ ████ ██ ███ ██████ ███████ ██████ ████ █████ ██████ █████ ██ ███████ █████ ███ ████████ ██ ██████
The oceanographer is not arguing that trapping the carbon dioxide for centuries is required for pumping it into the ocean. She is only arguing that it is a reason to do it.