UPSC Prelims 2019 CSAT Paper II · Q8 of 79 Comprehension medium

Passage

Passage - 7 Around 56 million years ago, the Atlantic Ocean had not fully opened and animals, perhaps including our primate ancestors, could walk from Asia to North America through Europe and across Greenland. Earth was warmer than it is today, but as the Palaeocene epoch gave way to Eocene, it was about to get much warmer still — rapidly and radically. The cause was a massive geologically sudden release of carbon. During this period called Palaeocene - Eocene Thermal Maximum or PETM, the carbon injected into the atmosphere was roughly the amount that would be injected today if humans burned all the Earth's reserves of coal, oil and natural gas. The PETM lasted for about 1,50,000 years, until the excess carbon was reabsorbed. It brought on drought, floods, insect plagues and a few extinctions. Life on Earth survived — indeed, it prospered — but it was drastically different.

Based on the above passage, the following assumptions have been made : 1. Global warming has a bearing on the planet's biological evolution. 2. Separation of land masses causes the release of huge quantities of carbon into the atmosphere. 3. Increased warming of Earth's atmosphere can change the composition of its flora and fauna. 4. The present man-made global warming will finally lead to conditions similar to those which happened 56 million years ago. Which of the assumptions given above are valid ?

  1. (a) 1 and 2
  2. (b) 3 and 4
  3. (c) 1 and 3 ✓ UPSC's answer
  4. (d) 2 and 4

Why the answer is (c)

• Assumption 1 is valid because the passage states that the rapid warming during the PETM led to drastic changes in life, indicating a direct link between global warming and biological evolution.

• Assumption 3 is valid because the text explicitly mentions that life became 'drastically different' and experienced extinctions due to the increased warming, confirming that atmospheric warming changes flora and fauna composition.

• Assumption 2 is invalid because the passage attributes the carbon release to a 'massive geologically sudden release' without stating it was caused by the separation of land masses; the land connection is mentioned only for animal migration.

• Assumption 4 is invalid because the passage compares the *amount* of carbon released in the PETM to potential human emissions but does not assert that current man-made warming will inevitably lead to the specific historical conditions of 56 million years ago.

• Therefore, only assumptions 1 and 3 are supported by the text, making option (c) the correct answer.

Why the other options are wrong

(a) 1 and 2
Assumption 2 is incorrect because the passage does not state that the separation of land masses caused the carbon release.
(b) 3 and 4
Assumption 4 is incorrect because the passage does not predict that present-day warming will result in conditions identical to the PETM.
(d) 2 and 4
Assumptions 2 and 4 are both incorrect as the passage does not link land separation to carbon release nor guarantee that current warming will replicate the PETM conditions.

Asked in the CSAT Paper II of the UPSC Civil Services Preliminary Examination 2019, held on 2 June 2019. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.

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