Reading Comprehension

PT106 · S4 · P2 · Q7 Volcanoes

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Long after the lava has cooled, the effects of a major volcanic eruption may linger on.

Topic

The lingering climate effects of major volcanic eruptions and how they influence global and regional temperatures.

Framework

Present Debate

Main Point

While volcanic eruptions are thought to cool Earth's climate, recent research suggests the cooling effect is smaller and more complicated than previously believed, with global impacts being minor but potential for larger regional effects due to feedback loops. (The “most valuable sentence” encapsulating the main point appears in P3: )

P1: Common Belief about Volcanic Eruptions

After a big volcano erupts, the dust and acid it throws into the air can cool the planet by blocking sunlight—some even blame Tambora’s 1815 eruption for an entire summer without warm weather in 1816.

P2: New Findings Challenge Conventional Wisdom

Scientists Mass and Portman say this connection isn’t quite as strong as we think. By analyzing global temperatures around nine eruptions—while accounting for El Niño’s effects—they find the supposed volcanic cooling can be tricky to pin down.

P3: Refining the Evidence—What Eruptions Really Do

Once they filtered out El Niño, they saw that smaller eruptions don’t noticeably affect temperatures, and even huge eruptions only slightly cool the hemisphere—much less than earlier studies had claimed.

7.

Not taking the effects of El Niño into account when figuring the effect of volcanic eruptions on Earth's climate is most closely analogous to not taking into account the

  1. weight of a package as

    Bad Match

    There isn't a background condition like El Niño here, that is sometimes off / sometimes on, and that would make something look more or less impactful than something really is. This is just talking about a sum of two weights, vs. each component value in that sum.

    18% picked this

  2. monetary value of the coins

    Bad Match

    There isn't a background condition like El Niño here, that is sometimes off / sometimes on, and that would make something look more or less impactful than something really is. This is just talking quantity of items vs. value of items.

    2% picked this

  3. magnification of a lens when

    Bad Match

    The magnification of a lens wouldn't ever change the shape of an object seen through the lens. If you're looking at a triangle through a microscope, it could be bigger or smaller, but it's still a triangle. You're not going to think the entire object is the wrong shape, just because you failed to account for magnification (if you magnified the lens enough that you weren't able to see the whole shape, there's no reason you would think, "Well ... I guess the stuff I can see right now is the entire shape.") You would move the object around enough to see its edges.

    6% picked this

  4. number of false crime reports

    Weak Match

    This is somewhat tempting, because the number of false crime reports would artificially increase the perceived data on number of crimes committed. This one doesn't match as well as the correct answer because the effect of false crime reports would always artificially inflate the data on crimes. With El Niño, there was the chance that it would skew our perception of the effects of a volcano in either direction (believing it had more effect than it really did or less), depending on whether an El Niño was coming or going when an eruption occurred. The correct answer has the potential to skew the data in both directions.

    30% picked this

  5. Correct

    ages of new immigrants to

    Why this is right

    The ages of new immigrants has the power to skew the average age of the population in either direction (just as El Niño had the power to give researchers the wrong impression about the effects of a volcano in either direction). If the average age of a population is 35, and then a bunch of immigrants arrive with an average age of 40, then that will have the effect of increasing the average age of that country's population. (If there were no immigration, then a shift upwards in average age usually means that life spans are extending or that birth rate is declining). If the average age of a population is 35, and then a bunch of immigrants arrive with an average age of 30, then that will have the effect of lowering the average age of that country's population. (If there were no immigration, then a shift downward in average age usually means that life spans are decreasing or that birth rate is increasing).

    Skill tested: Analogy · how this choice captures the passage's function is the move to repeat next time.

    44% picked this

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