The US should stop exporting oil — that would make a big reduction in greenhouse gas emissions.

The comparison with smallpox-infested blankets (which the US government gave to some indigenous groups during the 1800s) is misguided, since those two wrongs are wrong in different ways. The blankets were intended to, and likely to, kill only people in the targeted groups. Burning more oil, no matter who does it, is likely to kill more people all around the world. The one was a sneaky, treacherous act of war; the other a contribution to global suicide.