Public policy is all about trade-offs. Economists understand this better than politicians because voters want to have their cake and eat it too, and politicians think whatever is popular must also be true.
Economists understand that if we put a chicken in every pot, it might cost us an aircraft carrier or a hospital. We can build a hospital, but it might come at the expense of a little patch of forest. We can protect a wetland, but that will make a new school more expensive.
You get it already. But in the history of trade-offs, never has there been a better one than trading a tiny amount of global warming for a massive amount of global prosperity. Earth got about 0.7 degrees Celsius warmer in the 20th century while it increased its GDP by 1,800 percent, by one estimate. How much of that 0.7 degrees can be laid at the feet of that 1,800 percent is unknowable, but let's stipulate that all of the warming was the result of our prosperity and that this warming is in fact indisputably bad (which is hardly obvious). That's still an amazing bargain. Life expectancies in the United States increased from about 47 years to about 77 years. Literacy, medicine, leisure and even, in many respects, the environment have improved mightily over the course of the 20th century, at least in the prosperous West.
Given the option of getting another 1,800 percent richer in exchange for another 0.7 degrees warmer, I'd take the heat in a heartbeat. Of course, warming might get more expensive for us. There are tipping points in every sphere of life, and what cost us little in the 20th century could cost us enormously in the 21st - at least that's what we're told. And boy, are we told. We're (deceitfully) told polar bears are the canaries in the global coal mine. Al Gore even hosts an apocalyptic infomercial on the subject, complete with fancy renderings of New York City underwater.
Skeptics are heckled for calling attention to global warming scare tactics. But the simple fact is that activists need to hype the threat, and not just because that's what the media demand of them. Their proposed remedies cost so much money - bidding starts at 1 percent of global GDP a year and rises quickly - they have to ratchet up the fear factor just to get the conversation started.
The costs are just too high for too little payoff. Even if the Kyoto Protocol were put into effect tomorrow - a total impossibility - we'd barely affect global warming. Jerry Mahlman of the National Center for Atmospheric Research speculated in Science magazine that "it might take another 30 Kyotos over the next century" to beat back global warming.