I think it's fair to say the US probably has to hit net zero emissions by somewhere around 2030 for the world to stay below 1.5°C of global warming. (Whether that's feasible or not is a different question.) /1

It's true the IPCC doesn't specify this. They just say that the world *as a whole* probably needs to get to net zero by somewhere around ~2050 to limit to 1.5°C with little overshoot. And the world would need to hit net zero by ~2070 to stay below 2°C. /2