Question 120·Hard·Rhetorical Synthesis
While researching a topic, a student has compiled the following notes:
- The distance between Paris and Berlin is approximately 878 kilometers.
- Average carbon dioxide emissions per passenger‐kilometer (pkm): short-haul commercial flight—245 g CO2/pkm; high-speed electric train—41 g CO2/pkm.
- Even when electricity is generated from Germany’s relatively carbon-intensive grid, high-speed trains emit no more than 50 g CO2/pkm.
- Aviation is responsible for about 3% of total global carbon emissions, and rail for less than 1%.
The student wants to counter a claim that traveling by high-speed train from Paris to Berlin releases more carbon dioxide per passenger than taking a flight on the same route. Which choice most effectively uses relevant information from the notes to refute that claim?
For questions that ask you to use research notes to support or refute a specific claim, start by underlining the task word (support, refute, explain) and the exact claim being discussed. Next, scan the notes for the most directly relevant data—often a numerical comparison or a clear factual statement that lines up with the claim’s topic and scope (here, emissions per passenger on the same route). Then eliminate any choices that (1) talk about a different scale (global vs specific trip), (2) ignore the key numbers, or (3) reverse or misinterpret the comparison. Choose the option that both accurately reflects the notes and clearly does what the prompt asks (in this case, shows the claim is wrong).
Hints
Clarify the goal
Focus on what the student wants to do: are they trying to support the claim, question it, or prove it wrong? Make sure the answer you pick matches that goal.
Locate the key comparison in the notes
Look for the bullet point that directly compares carbon emissions for short-haul flights and high-speed trains. Ask yourself which numbers are given and how different they are.
Think about distance and totals
Since both the train and the plane travel the same 878 km, which matters more for comparison: the raw distance, or the emissions per passenger-kilometer?
Check relevance and direction
Eliminate any choice that: (1) doesn’t clearly compare train vs. plane on this route, or (2) ends up agreeing with or dodging the original claim instead of clearly contradicting it.
Step-by-step Explanation
Understand the task: what must the student do?
The question says the student wants to counter (refute) a claim: that traveling by high-speed train from Paris to Berlin releases more CO₂ per passenger than flying.
So the correct answer must:
- Directly compare train vs. plane on this specific route.
- Show that the claim is wrong by showing the train releases less, not more, CO₂ per passenger.
Find the most relevant notes
Look at the bullet points and ask: which ones directly compare train and plane emissions per passenger on the same distance?
Relevant bullets:
- "Average carbon dioxide emissions per passenger‐kilometer (pkm): short-haul commercial flight—245 g CO₂/pkm; high-speed electric train—41 g CO₂/pkm."
- "Even when electricity is generated from Germany’s relatively carbon-intensive grid, high-speed trains emit no more than 50 g CO₂/pkm."
These show that per passenger-kilometer, trains emit much less CO₂ than flights.
Translate the data into a clear counterargument
If a flight emits 245 grams of CO₂ per passenger-kilometer and a high-speed train emits about 41 grams (or at most 50 grams even on a carbon-heavy grid), then for the same distance the train will produce much lower emissions per passenger.
Because the Paris–Berlin distance is the same for both modes (878 km), multiplying by that distance gives a much smaller total for the train than for the plane. That directly contradicts the claim that the train emits more per passenger on this route.
Check each option against the task and notes
Now evaluate the answer choices:
- Choice A says air and rail produce similar emissions and even says this supports the original claim. That does not refute the claim and ignores the big difference between 245 g and 41 g per passenger-km.
- Choice B claims it’s impossible to know which emits more due to electricity uncertainty, but the notes actually give a clear upper limit (no more than 50 g), so we can compare.
- Choice C talks about global percentages (3% vs less than 1%), which is not the same as comparing this specific trip per passenger.
- Choice D uses the per-passenger-kilometer numbers (41 vs 245 grams), explains that the train emits only about one-sixth as much CO₂ as the flight, and concludes that the train releases far less carbon.
Therefore, Choice D is correct because it accurately uses the numerical data from the notes to show that the train emits far less, not more, CO₂ per passenger on the Paris–Berlin route, clearly refuting the claim.