Logical Reasoning

PT147 · S1 · Q10 The more sunlight our planet reflects back

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The more sunlight our planet reflects back into space, the cooler the global atmosphere tends to become.

Conclusion (therefore)

The more of Earth's surface is covered with snow and ice, the cooler the global temp is likely to become.

Evidence

The more sunlight our planet reflects back into space, the cooler the global atmosphere tends to get. Snow and ice reflect more sunlight than ocean or exposed land surfaces do.

Evaluate

The conclusion is positing a causal idea, the more the surface is covered with snow and ice, the cooler the globe will be, because when the surface is covered with snow and ice it reflects more light back into space, which cools the globe.

It seems like a reasonable argument with no glaring flaws. Let's try to debate it. The conclusion is a comparison between our Current World and a world with more of the surface covered by snow/ice.

We know one thing that would be different in that world (more sunlight reflected into space). That thing could cool the globe. But what else would be different? Maybe there are other geological processes that affect global temperature, and maybe in a world where more of the surface was covered by snow/ice, those geological processes would be changed in a way that would warm the globe.

Goal

Since the possible vulnerability of this argument would be , the correct answer might rule out that sort of change.

Or maybe it will just give us more reason to believe that in a snowy / icy world, the global temp is cooler.

10.

Which one of the following, if true, would most strengthen the argument?

Low atmospheric temperatures are required
No Impact
This answer is telling us what's required for snow. Who cares? We're trying to judge the hypothetical effects of having more snow / ice. How snow is created doesn't help us evaluate whether more snow would cool the globe.
9% picked this
Other factors besides the reflectivity
Weakens
This opens the doorway to possible objections. Maybe these other factors would actually contribute to a warmer globe, in a snowy / icy world. A strengthener would say, "No other factor besides reflectivity (i.e. my Evidence) is relevant when it comes to cooling the atmosphere (i.e. my Conclusion)."
1% picked this
Correct
Ocean water and land heated
Why this is right
Since land heated by sunlight warms the atmosphere, it lends some support to the idea that land covered with snow and ice would be less heated by sunlight and so would less-warm Earth's atmosphere. Thus it's adding some support to the idea that land covered by snow/ice, rather than uncovered, will lead to a cooler atmosphere. This answer is a dud, but it does more than anything else does. It feels like it just reinforces what we already know. We were told that snow/ice is better at reflecting sunlight back into space, which makes the atmosphere cooler. We understand --- "Get that radiation out of here!", snow says, like an NBA center swatting a shot into the 10th row. By sending the radiation back into space, it doesn't get trapped in our atmosphere, adding to our atmosphere's warmth. Meanwhile, uncovered land and ocean don't reflect the light, they absorb it. Since they absorb the radiation, the Earth gets warmer. So isn't this answer just reiterating that same fact? That sunlight gets absorbed and heats up the ocean / land / atmosphere? Not quite. It's explaining to us how the non-reflected (absorbed) light actually has any effect on the atmosphere. Someone might have thought, "Cool, ocean and land don't reflect light. They just absorb it. That just means that the land and the ocean water will be warmer. That doesn't mean global atmospheric temps will be lower!" This answer spells out, "Yes. Yes, it does."
Skill tested: Strengthen · how this choice captures the argument's function is the move to repeat next time.
59% picked this
The atmosphere derives most of
Unclear Impact
This answer is tempting because it seems to augment the importance of the evidence. "Our evidence was talking about sunlight passing in (and out) of Earth. Our conclusion was about atmospheric cooling. Most of atmospheric temp is connected to passage of sunlight." The reason I think this answer breaks down is that it seems to suggest that the snowy/ice world would actually be a source of more heat for the atmosphere. We're judging a world with more snow/ice vs. a world with less. In which world is there more sunlight passing through the atmosphere? There might be more sunlight passing through the atmosphere in the snow/ice world, since that world reflects more sunlight back into space. Every photon passes through on its way in, and then passes through the atmosphere again on its way out. Meanwhile, a photon that only passes in and then gets absorbed by land or ocean, only passes through the atmosphere once.
20% picked this
Lighter-colored soil reflects more sunlight
No Impact
This would only strengthen in the sense of making it seem like brighter things, like snow or ice or light soil, are better at reflecting. We have already established in the evidence that snow/ice is better at reflecting, so suggesting that light coloration is the reason why adds nothing to our case.
11% picked this

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