If GW was only about slowly warming up it wouldn't be so bad. But the main problems will be and are occurring due to things like drought, floods, and extreme weather both hot and cold and more unusual and powerful. We are seeing this already around the world. There simply is more energy in the atmosphere now. The rapidly changing and extreme conditions will cause problems with agriculture and ecosystems. Heat waves will kill. As they did in 2003 in France when 14 thousand people died. Water will become scarce as snowpacks fail to materialize. Old growth forests will die as they cannot take the changes. The oceans will become even more acidic destroying coral reefs and possibly crashing the marine ecosystem and much of our food supply from the seas. Bottom line, ecosystems and agriculture and humans don't like changes that need adapting to. These extremely fast climate changes we are seeing are unmatched historically and will cause productivity, species and population reductions. Some of this will happen no matter what we do now. But if we burn all the FF in the ground we invite certain catastrophe.
Burt Rutan is a great aeronautical engineer. But he is not a scientist and in this area he is a fool.