2. Humanity contributes to the warming to some extent but far less than some believe and more than others admit.

I don't think there is any reliable way to determine this. Since we don't have an extra earth to use for a control, the best estimate of humanity's effect on earth temperature comes from (queue the creepy music...) models (somebody administer smelling salts to Phil and Larry). Other efforts to determine man's affect on warming rely on common sense (otherwise known as pulling it out of your rear).

3. Nothing significant will be done about it. Perhaps the USA will be cut off at the knees but the worst offenders will press on...

My rear says that American companies will lead the way in greenhouse remediation, green energy, energy-saving tech, etc. and the net will be that we will make out like bandits. Some industries will be hurt, some new ones will replace them, the economy will do just fine.

4. Over the next 100 years the results will be less than predicted by the most fearful and perhaps more than predicted by those that choose to ignore the problem.

I hope your rear is right.

5. Hopefully in a hundred years we will be moving off of this rock. That is the only long term solution unless you want to jump on the Ebola bandwagon.

I could not make a statement like that without Tom jumping on his radical environmentalist bandwagon.