Its not motivated by scientific or even ideological conviction. Its that the True Believers realize that if any part of their dogma is called into question, then their entire philosophical edifice is threatened and starts to unravel, even those issues that may have nothing to do with climate.

This may not be evident in people like the oil companies, or pure capital, who see it as merely a threat to their financial interests. They are perfectly capable of publicly opposing the concept while feverishly preparing for its consequences privately. But for those who have incorporated it into their world view and made it a part of their belief system, it must be opposed on quasi-religious grounds. This is why the objections to AGW are not necessarily scientific, but often rely on elaborate political conspiracy theories and shadowy cabals of sinister villains. Like Darwinian evolution, Climate Change isn't just wrong, and its proponents are not merely mistaken. It has to be a plot by the Lord of the Flies himself.