How accurate what is? it's a prediction that depends on how people act. Simple fact is, people are changing now. Solar, and other green resources are getting quickly cheaper and more efficient, and it is thanks to our support of it. Because of that, I don't think we will see any of these doomsday scenarios. Doesn't mean they would never have occurred if we hadn't changed.
I think we're doing too little too late, honestly. It might not be a "doomsday scenario" but shit is going to get rough for sure. We haven't even started slowing down the rate of change yet. There are going to be huge changes even if we were to completely drop fossil fuel usage today, and that is obviously not what's happening.
Well, the US has gone down a bit http://www.epa.gov/climatechange/ghgemissions/gases/co2.html I honestly can't find a source. I swear I heard somewhere that the rate at which emissions were increasing was going down.