Science · Environmental Science
Chapter 1: Environmental Systems and Science
Per what?
In 2022 China emitted about 11.4 billion metric tons of carbon dioxide from fossil fuels, the United States about 5.1 billion and India about 2.8 billion. Per person, the order changes: the United States about 15 tons, China about 8 and India about 2.
Which ranking is the honest one?
Make your guess to turn the page.
Still to come: 10 pages · Lab · Words to Know · What We Learned · 4 questions · Explain It in Writing · Open Questions
The idea this lesson is working on — Students read a rising total as a worse performance and take any published figure as the neutral one. The book divides the same emissions data three ways and gets three rankings, and the lab reverses a ranking of water-saving actions by switching from per person to total. Ask: per what, and since when? The idea to reach is that the choice of denominator and baseline is part of the argument and should be stated.
The figures and where they come from — Fossil carbon dioxide for 2022 is rounded from the Global Carbon Project; output uses GDP at purchasing-power parity (about $30 trillion for China, $25 trillion for the United States and $12 trillion for India). The baseline figures are the EPA Inventory of US Greenhouse Gas Emissions and Sinks for 2022. The Key West figures are from McClenachan (2009), Conservation Biology. The lab’s water savings are realistic orders of magnitude and its adoption shares are illustrative.
Mechanism, never a position — The book says what each denominator measures and does not say which one a country should be judged by, or who should cut what. Those are value questions of the kind lesson 1 separates out. What the student should leave with is the habit of asking "per what?" and "since when?" before accepting any comparison, from any side.