[tpunx99GSX]

I agree with a lot of your points, except the assumption that we do not know if we are in a high or low point. We do through the many tools they are using such as testing ice cores and other samples.
A 1* difference can actually have a significant impact. Remember we are talking about global averages, not the swing of weather. A 1* difference may not make a difference to humans, but plants, animals and insects it will affect such as migratory patterns.

I think the focus of talks needs to shift on a global scale and not a country scale, and the UN needs to be the driving force in this. While countries like China and Indonesia, and india are becoming some of the largest polluters, we cannot let our own get out of control as we are the ones consuming the products they are producing. So it is a US problem as well as a problem for China. we are the demand they are the supply.

Man made can come in many forms, not just automobiles, Autos are something that is the easiest to change. As americans we see the benefit not just from the environment but from the fact that we save at the pump by getting better gas mileage. So its an easy change for the administration to say "All auto manufacturers need to be above x mpg by this date" it gives a decent return for the environment and americans will hopefully welcome it with savings at the pump.
The other forms of human involvement is the use of fertilizers, Livestock overproduction (methane), dirty energies, and other stuff are more problematic to try and change. But regardless we need to on a global scale to set the precedent for other countries. This is a good change to show the world we are an innovator, not just a consumer.