As Bret Stephens explains it, the true believers in anthropogenic global warming don't need proof or science or data, because they believe. They want it to be true. They need it to be true.
The real place where discussions of global warming belong is in the realm of belief, and particularly the motives for belief. I see three mutually compatible explanations.
The first is as a vehicle of ideological convenience. Socialism may have failed as an economic theory, but global warming alarmism, with its dire warnings about the consequences of industry and consumerism, is equally a rebuke to capitalism. Take just about any other discredited leftist nostrum of yore – population control, higher taxes, a vast new regulatory regime, global economic redistribution, an enhanced role for the United Nations – and global warming provides a justification. One wonders what the left would make of a scientific "consensus" warning that some looming environmental crisis could only be averted if every college-educated woman bore six children: Thumbs to "patriarchal" science; curtains to the species.
These are the “watermelon” environmentalists – Green on the outside, Red on the inside. Any excuse to exert control over the great unwashed masses (that's you and me, folks) is just fine with them. If they can't sell outright overt socialism, then they can use global warming as a back door entry into the lives of the world's population.
A second explanation is theological. Surely it is no accident that the principal catastrophe predicted by global warming alarmists is diluvian in nature. Surely it is not a coincidence that modern-day environmentalists are awfully biblical in their critique of the depredations of modern society: "And it repented the LORD that he had made man on the earth, and it grieved him at his heart." That's Genesis, but it sounds like Jim Hansen.
And surely it is in keeping with this essentially religious outlook that the "solutions" chiefly offered to global warming involve radical changes to personal behavior, all of them with an ascetic, virtue-centric bent: drive less, buy less, walk lightly upon the earth and so on. A light carbon footprint has become the 21st-century equivalent of sexual abstinence.
Hmm. Where have we heard this line of reasoning before? Could it be from folks like the Taliban, al Qaeda, and other militant fundamental religious cults of a number of faiths? They want us to return a few centuries into the past, eschewing the modern conveniences all in the name of saving the earth. But it wouldn't surprise me that they would exempt themselves from such restrictions because they would need much of that technology to keep an eye on the rest of us, right? Of course it would also mean we would then fall prey to illnesses and diseases we rarely see anymore because the means to treat them would be against God's will...except for them, of course.
Finally, there is a psychological explanation. Listen carefully to the global warming alarmists, and the main theme that emerges is that what the developed world needs is a large dose of penance. What's remarkable is the extent to which penance sells among a mostly secular audience. What is there to be penitent about?
As it turns out, a lot, at least if you're inclined to believe that our successes are undeserved and that prosperity is morally suspect. In this view, global warming is nature's great comeuppance, affirming as nothing else our guilty conscience for our worldly success.
This last one ties in closely with the second one, and makes me wonder what our ancestors from 100 or 200 years ago would say about this foolishness.
I have little doubt the Founding Fathers would be walking around dope-slapping the lot of these AGW believers. They would see it for the foolishness it is, as would anyone from back then. This need to 'voluntarily' dismantle a society based solely upon an over-hyped and unproven theory would be seen for what it is: stupidity.