California tax is 41.7 cents per gallon (5th highest in US) plus the cap’n’trade carbon tax plus 2.25% sales tax on total cost per gallon.
But Californians can be smug about all they’re doing to combat climate change (i.e., nothing significant.)
Based on my math, that’s $0.129/gallon for the cap’n’trade tax, based on a current CNT auction cost of $14.52/metric ton of CO2 (indulgence cost), and a gasoline conversion factor of 8.887 × 10-3 metric tons CO2/gallon of gasoline burned.
Sources
CNT indulgence cost
https://www.arb.ca.gov/cc/capandtrade/auction/auction.htm
Conversion factor
https://www.epa.gov/energy/greenhouse-gases-equivalencies-calculator-calculations-and-references