Two rankings of carbon emissions circulate in almost every climate discussion, and they produce opposite lists. Ranked by total output, China and the United States dominate. Ranked by emissions per person, neither China nor India appears in the top eight at all, and the list is headed by countries most people could not place on a map.
The per-capita table is a list of petrostates
Qatar leads at roughly 32.4 tonnes of CO2 per person, followed by Kuwait at 24.1, the United Arab Emirates at 22.8 and Bahrain at 22.3. Australia, the United States, Canada and Saudi Arabia follow between 14 and 15 tonnes.
The top four share a specific profile: small populations, enormous hydrocarbon industries, and climates that make air conditioning a necessity rather than a comfort. Gas liquefaction is extraordinarily energy-hungry. So is desalination, which is how these countries get fresh water. Divide that industrial energy use by a population of a few million and the per-person figure becomes very large.
Neither ranking is a trick
It is tempting to treat one of these as the honest measure and the other as spin. Both are legitimate; they answer different questions.
Total emissions answer: whose output has to fall for the global figure to fall? On that question China and the United States are unavoidable, and Qatar is a rounding error.
Per-capita emissions answer: how carbon-intensive is one person's life here? On that question a Qatari resident's footprint is roughly twice an American's and many times an Indian's.
Arguments about climate responsibility usually turn on which question the speaker considers the real one. Countries with large populations and low per-person emissions prefer the per-capita frame. Countries with small populations and high per-person emissions prefer the total frame. Both are quoting real numbers.
A third measure neither ranking captures
There is a further complication that neither table shows: emissions are counted where they are produced, not where the resulting goods are consumed. A factory in China making goods for European buyers books its emissions to China.
Consumption-based accounting, which reassigns those emissions to the final purchaser, raises the figures for wealthy importing countries and lowers them for manufacturing exporters. It is harder to calculate and therefore quoted less, but it is arguably closer to what most people mean when they ask who is responsible.
How to read a ranking like this
The practical lesson generalises well beyond emissions. Whenever a per-capita ranking and a total ranking disagree sharply, the disagreement is usually the interesting part. It tells you the quantity is concentrated somewhere unusual relative to population.
The same effect shows up in crude oil production, where the United States leads on volume while small Gulf states lead on output per citizen, and in beer consumption, where the Czech Republic tops the per-person table while far larger countries drink more in total. When someone cites a ranking without saying which of the two it is, that omission is doing work.