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?
In rhetorical synthesis questions, match the scope of the claim (here: CO₂ per passenger on a specific route) to the most directly relevant note(s) (here: emissions per passenger-kilometer for train vs flight, including the stated upper bound). Then pick the choice that states that comparison accurately and draws the correct conclusion, while eliminating choices that shift to a different scope (global shares) or introduce uncertainty the notes already resolve.
Hints
Restate the claim in your own words
The claim says: for the Paris–Berlin trip, the train causes more CO₂ per passenger than flying. You need an option that proves the opposite.
Find the note that gives a direct comparison
Which bullet gives emissions for flights and for high-speed trains in the same units (per passenger-kilometer)?
Use the “no more than” information
One note gives an upper bound for train emissions even on a carbon-intensive grid. How does that upper bound compare to the flight value?
Eliminate scope shifts
Cross out choices that talk about global percentages or policy priorities instead of comparing train vs plane on this specific trip.
Step-by-step Explanation
Identify what the sentence must do
The student must refute the claim that taking a high-speed train from Paris to Berlin releases more CO₂ per passenger than flying the same route.
Use the most direct notes for a route comparison
The most relevant notes give emissions per passenger-kilometer:
- Flight: 245 g CO₂/pkm
- High-speed train: 41 g CO₂/pkm
- Even on Germany’s grid: train is no more than 50 g CO₂/pkm
These allow a direct train-vs-plane comparison for the same trip.
Connect per-kilometer rates to the same distance
Because both modes cover the same Paris–Berlin distance (878 km), the option with the lower CO₂ per passenger-kilometer will also have the lower total CO₂ per passenger for the trip.
Select the choice that clearly contradicts the claim using the notes
The first choice directly uses the notes’ numbers (train ≤ 50 g CO₂/pkm vs flight 245 g CO₂/pkm) to show the train emits far less CO₂ per passenger on the Paris–Berlin route, so it most effectively refutes the claim.