LSAT 106, Section 4, RC Passage 2, Volcanic Cooling

RC Passage 2 Explanation

Paragraph Summaries

1. Scientists have traditionally thought volcanic dust lingers in the atmosphere and cools the earth.
2. Mass and Portman say this effect is not as strong as we thought. El Nino can also cause cooling or warming.
3. Once El Nino is removed, even major eruptions have little global impact.
4. Other researchers say that even a small global cooling effect could lead massive regional cooling, through feedback effects.

Analysis

The author agrees with Mass and Portman’s reevaluation of volcanos’ global temperature effects.

Mass and Portman showed that El Nino was the cause of most of the cooling.

But in the fourth paragraph, the author qualifies Mass and Portman’s conclusion. Major eruptions could still cause massive regional cooling, thanks to feedback effects. A feedback effect occurs when a small change in a variable leads to a much larger change in that same variable.

On this passage, it’s important to know where to find information. Each paragraph has a theme. Finding information quickly is the skill to learn for Reading Comprehension success.

There’s a basic logical flaw in this passage that never comes up in the questions. The traditional view is that the “year without a summer” was caused by cool weather.

It shouldn’t matter much whether the cooling was caused by both El Nino and volcanos. The Earth was still cooler, even if El Nino was partly responsible!

e.g. If El Nino cooled the Earth 1 degree and the volcano cooled it 1.5 degrees, the earth is still 1.5 degrees cooler.

That 1.5 degrees might have been enough to set off massive regional cooling.