Having made several contributions to this thread,that for the most part have been unhappily received, I would like to add a couple of other comments.
The evidence that climate change is ocurring is proved. But what is climate other than a standstill event among numerous superimposed cycles of change over the aeons? There is an increase in CO2 since industrialisation. The complexities of climate change and the models constructed to explain it are imperfectly understood, therefore to extract one variable i.e. CO2 and give it a ranking of it's contribution to the present changes presents further levels of difficulty.
   Having stated the above there is another far more important aspect of the equation that is given very little mention. Humanity is now an industrialised being, and like nuclear energy the genie is out of the bottle.To reduce the carbon footprint to levels seen before the Industrial Revolution with the present tools at our disposal, many unpalatable truths have to be faced:
No lights
No cars
No tractors
No oil based medicines
No oil based fertilizers
A collapse of modern agriculture
A collapse of urban centers
A collapse of population numbers
It has been stated that one gallon of fuel provides the work of 100 slaves.
We have become soft and indolent and few of us could survive, even assuming we could relearn the required skills.
As yet alternative technologies can make a contribution so small as to be insignificant.
For the near future we are stuck with a carbon based economy irregardless of the morality of this situation.