With one-sixth the current population, with 0% as many cars, and 0% as much refrigeration?
Trying to settle how many greenhouse gases come from cars, I found these two charts:
https://www.epa.gov/ghgemissions/sou...-gas-emissions
https://www.epa.gov/greenvehicles/fa...-gas-emissions
So, personal vehicles contribute 16.8% to the total.