I agree human activity is increasing the CO2 levels.
But without human intervention, the ice age will still end, and the unusually low temperature will revert to mean and stay there for over a hundred million years.
http://www.biocab.org/Geologic...
I agree with your point that wildlife can only adapt so fast and many of your other points.
However, in terms of risk/reward and money spent- we would be much more productive spending similar amounts of money on tracking and stopping asteroids.
So it's "compared to what" and "with limited funds- where is the best place to spend it".
Also, since we are not going to enforce these rules on China and India, any costly efforts in the rest of the world will be pointless. I have made huge personal reductions to my own carbon footprint- and at minimal cost.
However, fast science is usually bad science. And many of the models and predictions have been hysterically wrong. After Rita and Ike, we were going to be hammered with season after season of 2-3 super storms and 7+ named storms doing billions of dollars of damage a year. And instead nothing happened.
On one point I agree with you. The scale on the graphic is log scale and misleading. We should probably still be in the trough of the ice age for a substantial period if you look at it with a linear scale.