I’m not a global-warming believer. I’m not a global-warming denier. I’m a global-warming agnostic who believes instinctively that it can’t be very good to pump lots of CO2 into the atmosphere, but is equally convinced that those who presume to know exactly where that leads are talking through their hats.

Predictions of catastrophe depend on models. Models depend on assumptions about complex planetary systems — from ocean currents to cloud formation — that no one fully understands. Which is why the models are inherently flawed and forever changing. The doomsday scenarios posit a cascade of events, each with a certain probability. The multiple improbability of their simultaneous occurrence renders all such predictions entirely speculative.

Yet on the basis of this speculation, environmental activists, attended by compliant scientists and opportunistic politicians, are advocating radical economic and social regulation. “The largest threat to freedom, democracy, the market economy and prosperity,” warns Czech President Vaclav Klaus, “is no longer socialism. It is, instead, the ambitious, arrogant, unscrupulous ideology of environmentalism.”

If you doubt the arrogance, you haven’t seen that Newsweek cover story that declared the global-warming debate over. Consider: If Newton’s laws of motion could, after 200 years of unfailing experimental and experiential confirmation, be overthrown, it requires religious fervor to believe that global warming — infinitely more untested, complex, and speculative — is a closed issue.

But declaring it closed has its rewards. It not only dismisses skeptics as the running dogs of reaction, i.e., of Exxon, Cheney, and now Klaus. By fiat, it also hugely re-empowers the intellectual Left.

For a century, an ambitious, arrogant, unscrupulous knowledge class — social planners, scientists, intellectuals, experts, and their left-wing political allies — arrogated to themselves the right to rule either in the name of the oppressed working class (Communism) or, in its more benign form, by virtue of their superior expertise in achieving the highest social progress by means of state planning (socialism).

Two decades ago, however, socialism and communism died rudely, then were buried forever by the empirical demonstration of the superiority of market capitalism everywhere from Thatcher’s England to Deng’s China, where just the partial abolition of socialism lifted more people out of poverty more rapidly than ever in human history.

Just as the ash heap of history beckoned, the intellectual Left was handed the ultimate salvation: environmentalism. Now the experts will regulate your life not in the name of the proletariat or Fabian socialism but — even better — in the name of Earth itself.

Environmentalists are Gaia’s priests, instructing us in her proper service and casting out those who refuse to genuflect. (See Newsweek above.) And having proclaimed the ultimate commandment — carbon chastity — they are preparing the supporting canonical legislation that will tell you how much you can travel, what kind of light you will read by, and at what temperature you may set your bedroom thermostat.