The IPCC does not predict "a couple of degrees," in the sense that 2.0C is the upper boundary. That's about a midline case.
Yes, that was what our best scientists think is the most likely scenario. If you're going to claim a scientific basis for your argument then that's the one you've got to go with. The IPCC also listed little or no change as a possibility but you wouldn't think it reasonable for me to base my argument on that right?
>> "Humans are only responsible for a small fraction of the CO2 going into the atmosphere."
That's true. But we're responsible for basically all of the change in CO2 concentrations over the last hundred years....
Yes, I'm well aware of all of that.
We keep using China as an excuse for ignoring our own responsibilities, even though they only emit about a quarter what we do on a per-capita basis.
What possible logic suggests that CO2 levels are more effected by per-capita output than total output? Imagine for a moment that tomorrow the U.S. instituted a 90% tax on the top 10 CO2 producing industries. The result would be that those industries would move to countries without such taxes and the production of CO2 would continue. It could be China but it could also be just about anywhere else too. All it takes is a handful of cheaters to ruin the whole plan. The only thing that would change for the U.S. is that we'd be poorer and less able to cope with the results.
Second, your projections assume that alternative energy technology will remain at its current cost. That simply will not happen. The cost of photovoltaics has been dropping by 50% every six years pretty much since the things were invented. It's a veritable Moore's Law of solar power, and it hasn't shown any sign of slowing. So within ten years, it's very likely that the cheapest way to add new energy to the grid will be with solar power.
If you're right (and I think you are) then we would be best off waiting until that happens.
Right now, the cheapest form of energy isn't coal or natural gas: it's energy efficiency
That is certainly true in some cases but there are so many subsidies and tax breaks and regulations on all sides it's really hard to be sure what the true cost of anything actually is. What I am pretty sure of is that current policies that take dollars from the poor via fees added on to their electric bill and transfer them to the rich in order to subsidise solar panels are probably counter-productive. The free market, for all it's faults, is generally better at math than Congress.