A friend recently sent me a short PowerPoint presentation, dated 2007, by a self-described libertarian physicist. The presentation warned that libertarians shouldn’t be too eager to argue the science of global warming, since it is at least plausible, and instead focus on whether CO2 emission must be limited by government.

I share my reply to my friend and the physicist below. I probably shouldn’t have gone on at such length, but as they say, it’s easier to write long than short:

Thanks for passing this along. Feel free to pass along my reactions to Dr. X. I mean no disrespect, and apologize for the length of what follows, but this reply flows easily because I’ve written and read and said it so many times before.

A physicist knows that carbon dioxide is a greenhouse gas, that its concentration in the atmosphere is rising due to human emissions, and that all else being equal this will lead to a warming of 1-2 deg. C if the concentration rises to 2X pre-industrial levels. These are important facts that nearly all skeptics concede. But these are not very important facts in the policy debate.

A physicist is no more likely than a sociologist to know what human emissions will be 50 years from now — if a slight warming would be beneficial or harmful to humans or the natural world; if forcings and feedbacks will partly or completely offset the theoretical warming; if natural variability will exceed any discernible human effect; if secondary effects on weather will lead to more extreme or more mild weather events; if efforts to reduce emissions will be successful; who should reduce emissions, by what amounts, or when; and whether the costs of attempting to reduce emissions will exceed the benefits by an amount so large as to render the effort counterproductive.

Uncertainty about these matters is pervasive in the science community. If the alarmists are wrong about even one or two of them, human greenhouse gas emissions move out of the realm of a nuisance requiring a response — whether by governments or via a (presently nonexistent) global property rights regime — and into the realm of speculation. For example, if modest warming and the fertilization effect of CO2 have boosted agricultural output around the world — something biologists have no doubts about — then the Third World owes the First World an enormous debt of gratitude for that positive externality of the Industrial Revolution, though that is not a debt the First World is entitled to collect.

I’m not a scientist, but I edited and coauthored parts of three volumes in the Climate Change Reconsidered series, nearly 2,000 pages consisting almost entirely of reviews of peer-reviewed research written by astronomers, biologists, climatologists, economists, geologists, oceanographers, and physicists. What I learned is that they have made some progress in answering the questions posed above. In particular, they are pretty sure that most of the warming of the late 20th century was natural, not man-made; that it was beneficial to humans and wildlife and not harmful; that it is virtually unstoppable by man; and that the costs of attempting to change the weather would erase two centuries of human progress.

Of course, it’s that final thing — “erase two centuries of human progress” — that is the objective of those who launched the global warming scare, keep it going despite the collapse of scientific support for its hypothesis, and reap enormous windfall profits from its subsidies and regulations. It’s been a political and social movement from start to finish, not a science-driven effort. Go back and read Julian Simon’s Hoodwinking the Nation, or the more recent Rupert Darwall’s The Age of Global Warming, a detailed history of the movement. Neither writer hardly ever mentions a scientist. They don’t need to.

Conceding the science to the alarmists would have been a terrible strategic mistake. We would have gotten cap and trade in 2009 or a carbon tax sometime since then. Trillions of dollars would have been wasted.

Here at The Heartland Institute, we have frequently debated the wisdom (or lack of wisdom) of taking the science seriously. Most free-market think tanks don’t. But failing to do so rendered them irrelevant in what is arguably the biggest public policy debate of our lifetimes. We decided not to debate “what should be done about global warming.” We looked under the hood at the science touted by the other side and found it to be utterly unpersuasive.

So we set out to persuade the public and their elected representatives that global warming is not a crisis, it needs neither a government solution nor a private property solution. Opinion polls and political outcomes in recent years show we were remarkably successful.

Maybe a libertarian think tank shouldn’t have taken up this task, but as I looked around seven years ago, and as I looked around every year since, I saw nobody else willing to do it.