Plots show a, Destination, b, source country-level, and c, CO2-CH4-N2O breakdown of volume-weighted-average crude oil refining CI curve (kg CO2eq bbl−1) in 2015. See definitions of destination and source country CI in Methods. Curves are sorted by increasing CI value. Colour scheme reflects continental grouping. For destination countries, 76% of them have a country-level refining CI that is lower than the global average. For source countries, this percentage drops to 59%. In fact, the top 10 refining countries consume 65% of global crude oil production and emit 69% of global refining emissions, while the top 10 oil production countries supply 69% of global crude oil production and are responsible for 70% of global refining emissions. Again, this skewness is due in part to one third of global crude oil production being refined in China and the US where most of their refineries are deep conversion. Also see Supplementary Table 3 for refining CI based on 20-year GWP settings.