CO2 is the dominant forcing greenhouse gas, and accounting on it is fairly straightforward so it makes sense to focus on that.

I agree that it's not enough though. We need both carbon neutral technology now as well as carbon capture in the future. However it is an order of magnitude or more easier to not emit now than it is to capture in the future, so we absolutely mush transition to carbon neutral as soon as possible, then use excess intermittent renewable energy to capture co2 from the air. We also need to incentivize that with carbon credits of some sort so that there are market forces.

That's what Paris is about, and why we need to be pushing our US politicians to ask for much more than what the Obama administration is going to ask for. We need much more aggressive strategies.