Canada. But there aren't that many of us, and the absolute number and political units also matter if you care about warming as a practical problem. There are two interesting things about per capita CO2eq in this graph.

1. China is still trending up and the US is still trending down. It's dangerous to make straight-line projections but they are on trend to meet at some point.

2. The US per capita emissions appear to be on a steady downward trend since 1850. This is even more obvious if you discount the anomalous periods of the civil war and the Great Depression. You have to admit, that's something that demands unpacking.

https://www.dropbox.com/scl/fi/s4fy286y7gwpqgmeltark/Screens...

Edit: Looks like Mongolia, Saudi Arabia, Bahrain, Kuwait, Qatar, and the UAE have the honour of being at the top actually. Might not be a comprehensive list.