My colleague (and blog contributor) Frank Ackerman has a new article on Grist that explains why the United States can’t afford to settle for the “social cost of carbon” estimate used in the fuel-efficiency and tailpipe emissions standards unveiled April 1.

As we outlined in our recent white paper, “The Social Cost of Carbon” (available on the E3 Network website), the $21-per-ton figure being used by the government as a “central estimate” of the damages caused by carbon dioxide emissions is based on flawed economics and questionable value judgments.

Frank’s article describes how the government came up with that number, and why the SCC is so important: It’s like a “volume dial” that determines how strict environmental standards should be. Even worse, as Congress considers a climate bill, the $21 SCC could be taken as the recommended level for a carbon tax or permit price:

If that happens, there is no way the United States could reach the widely discussed, science-based goal of cutting emissions by 80 percent by 2050, which would require a much higher price on carbon. Given how cost-benefit analyses dominate U.S. policymaking, a $21 SCC could have a devastating impact on environmental legislation.

It’s easy to think of the fuel-efficiency standards as yesterday’s news, and not discuss the SCC again until it comes up in Congress. But in fact, now is the time to do our homework and figure out what the true price of carbon should be – before that, too, is a done deal.

Paul Krugman’s excellent article in the New York Times Magazine this weekend contrasts a slow, incremental approach to greenhouse gas mitigation (such as William Nordhaus’ “climate-policy ramp”) to more rapid measures better fitting the urgency suggested by the climate science literature. Krugman dubs the latter the “climate-policy big bang.”

Krugman has done a nice job of describing some of the major points of disagreement within the field of climate economics. Here’s his view:

[T]he policy-ramp prescriptions seem far too much like conducting a very risky experiment with the whole planet. Nordhaus’s preferred policy, for example, would stabilize the concentration of carbon dioxide in the atmosphere at a level about twice its preindustrial average. In his model, this would have only modest effects on global welfare; but how confident can we be of that? How sure are we that this kind of change in the environment would not lead to catastrophe? Not sure enough, I’d say, particularly because, as noted above, climate modelers have sharply raised their estimates of future warming in just the last couple of years.

Krugman concludes that the “nonnegligible probability of utter disaster” should guide our climate policy, and that this “argues for aggressive moves to curb emissions, soon.”

Anyone who has been reading this blog will know already that I feel that the evidence of both the climate science and climate economics literatures overwhelmingly supports a big-bang climate-policy approach. It’s nice to know that Paul Krugman is a supporter of these views, and it’s even nicer to have his clear and influential thoughts on this reach such a wide audience.

An Obama administration task force has recently proposed that $21 per ton is an appropriate “social cost of carbon.” (The social cost of carbon, or SCC, is an estimate of the damage caused – both today and in the future – by the release of an additional ton of carbon dioxide into the atmosphere; it’s a topic that I’ve discussed frequently in this blog (see here, here, and here). A bigger SCC means that the federal government is willing to do more to more to slow greenhouse gas emissions; conversely, a smaller SCC means that fewer emissions abatement measures will be considered “economical.”) In an Economics for Equity & Environment white paper, released today, Frank Ackerman and I discuss the very serious errors and omissions that have led to EPA, OMB and other agencies’ promotion of what is a very low SCC.

As our paper demonstrates, the calculation of the SCC is less science than alchemy. It is also – like much of cost-benefit analysis – a very strange way of making decisions. Cost-benefit analysis sounds like common sense: weigh the costs of an action against the benefits. A good policy will have net benefits; a bad policy, net costs. Simple.

Well, actually, no, not so simple. There are (at least) three big problems:

Problem #1: When it comes to the greenhouse gas emissions (and many other environmental issues) we can’t measure the costs and benefits with any accuracy. We’ve never filled the atmosphere with CO2 before. We’ve never tried to remove large quantities of CO2 from the atmosphere before. Some of the important consequences of climate change, such as the loss of human lives and risks of extinction of endangered species, simply don’t have meaningful prices (although economists have at times made up dollar values for them). And many of the costs of halting emissions and benefits of averting damages will occur well into the future. That’s a lot of uncertainty, which doesn’t tend to increase the accuracy of economic predictions.

Problem #2: Many of the costs and benefits will affect not us, but our great-grandchildren, and there is a fair amount of disagreement (a least among economists) about how to weigh these future impacts in the decisions we make today. Some (like me) say we should weigh all damages equally regardless of whether it is us or our descendants that suffer the costs. Others feel that future costs (and benefits) are worth far less than those that take place today.

Problem #3: While climate policy will benefit humanity as a whole, the costs of reducing emissions and the benefits of avoiding a climate catastrophe will impact different people differently. Most people will be net gainers from climate policy (more benefits than costs), but some will be net losers (more costs than benefits). This is true both across generations – future generations are the biggest net gainers from climate policy – and among the Earth’s population today. As a broad generalization, poorer people have more to gain from climate policy. The more one weighs the interests of the net losers compared with the net gainers, then, the less one will conclude that we should do to avert climate change.

In short, cost-benefit analysis is complicated, and its results are open to a lot of interpretation. Regrettably, that is how the U.S. government makes decisions about environmental issues. In a cost-benefit analysis of emission reducing policies, the social cost of carbon is the benefit from each one-ton reduction in carbon emissions (it’s the damage that doesn’t happen, and thus, a benefit). A bigger SCC means a bigger benefit from reducing emissions, making it more likely that any particular carbon reduction policy will pass muster as delivering greater benefits than costs.

There is no way to truly measure the SCC. (Seriously, all climate damages throughout time reduced to one figure in today’s dollars? If you really have faith in such a figure, I have a bridge in Brooklyn that I’d like to sell you.) The Obama administration should consider looking at the problem of emissions abatement from an entirely different angle: For example, by how much do we need or want to reduce U.S. emissions, and what’s the cheapest way to do that? Alternatively, how much can we afford to devote to insuring ourselves against the danger of catastrophic climate change? Decisions made from starting points like these are far more likely than cost-benefit analysis to result in a climate policy that is both effective and economical.

It’s nice to win, now and then, in the battle against really bad economics.

Back in 2006, California adopted an ambitious state climate policy, known as AB 32. It will require higher fuel efficiency standards for cars and trucks, better insulation and energy efficiency in homes, and more vigorous promotion of renewable energy. Careful analysis by the state’s Air Resources Board and analysts at the University of California-Berkeley showed that AB 32 will have neutral to slightly positive effects on California jobs and incomes – a conclusion that was unacceptable to some of the bill’s opponents.

Last year, two reports trashing AB 32, and state regulation in general, were released by Sacramento State College business professors Sanjay Varshney and Dennis Tootelian (click here for the first, here for the second).  They projected that AB 32 would reduce the state’s overall income by 10 percent, and that regulation in general would shrink California’s output by one-third. Released with great fanfare, these super-sized critiques started showing up in media discussion of AB 32.

I did a report called “Daydreams of Disaster” for the California Attorney General’s office, evaluating the Varshney-Tootelian (V&T) studies. V&T assumed that all benefits of AB 32 were too speculative to include; in effect, they estimated benefits at exactly zero. The costs caused by AB 32, on the other hand, are treated with expansive generosity. Housing costs surge upward, based on the cost of converting homes to zero net energy consumption (but with no resulting savings on utility bills). The projected fuel savings from new, high-mpg cars are treated as a cost imposed on owners of older cars (but not a savings to new car owners). Food cost increases are estimated in an entirely data-free manner. V&T then multiply everything by 2.8 to account for indirect costs.

Even worse is the V&T critique of regulation in general. They estimate a single equation explaining state GDP, across the 50 states, based on six different rankings of state business climates from Forbes. Those rankings give every state a number from 1 (best) to 50 (worst); in the V&T equation, every one-point increase (worsening) in the “regulatory climate” ranking decreases state GDP by a bit more than $4 billion. California comes in at number 40 in the Forbes scorecard for regulatory climate, so V&T project losses to the state of more than $160 billion. And don’t forget to multiply the result by 2.8!

The worst mistake here, although not the only one, is this: State-by-state differences in the size of the economy are – surprise! – primarily determined by the population of the state, a factor left out by V&T. (Why does California have a bigger economy than Rhode Island? Because California is a bigger state with more people, not because of either state’s business climate or rankings in Forbes.) When I reran V&T’s analysis taking state population into consideration, the Forbes rankings had no correlation with the size of the state economy per capita.

My report was one of three independent evaluations of the V&T work, all reaching entirely negative conclusions. The word is starting to get around: the Legislative Analyst’s Office of the California legislature released its own analysis of the shoddy quality of the V&T reports; the head of Small Business California asked that the studies be removed from public websites, due to “deeply flawed methodologies and useless conclusions”; the story even made the San Francisco Chronicle last Friday, which quoted my summary remarks: “The losses they [V&T] project would be serious economic impacts – if they were real. They are, however, entirely unreal; they should be viewed merely as daydreams of disaster.”

There’s plenty more bad economics out there to do battle with. But it’s gratifying to see that there are some limits to what you can get away with in public debate.

Wait a second, the free carbon permits aren’t going to be given away on an equal per capita basis? Let me get this straight: The plan is to give free permits to pollute to the largest historical polluters? Why? Because otherwise, these most polluting industries will fight to block the climate legislation. Is this how all policy is made? We can’t pass a health bill that doesn’t include a giveaway to insurers? Would an anti-smoking measure have a little something in it for tobacco companies? A gun law with a present for the gun manufacturers? Well, probably this is how all policy is made.

Still, the purpose of climate legislation isn’t to make power companies happy, nor is it to guarantee them a continued stream of profits. Capitalism creates and destroys: There’s no guarantee that what made a profit today will make a profit tomorrow, and there is no obligation on the part of the voting public to shore up business models that are damaging to the public good. The purpose of climate legislation should be twofold, 1) to reduce greenhouse gas emissions, and 2) to do so in a way that promotes equity.

Yes, assuming a particular overall cap on carbon, giving the permits away instead of selling them should end up with the same reduction in emissions. (To get this result, the permits would have to be fungible – that is, after they are given away or bought from the government, they can then be sold again to the highest bidder; this leads to the efficient market solution that neo-classical economists are always yammering about. The companies that can reduce their carbon emissions most cheaply will do so and sell the permits they do not need to companies for whom it would cost more to reduce emissions.)

But here’s what would be different: If the government sells the permits, that revenue can go to reduce taxes, or support green jobs, or send a dividend check to every citizen. If the government gives away the permits to private companies, the value of the right to pollute the atmosphere (which, as I’ve mentioned, belongs to every global citizen on an equal per capita basis) ends up going to the same malefactors that have been getting this windfall for decades.

Personally, I don’t think that having made a profit in the past gives you some sort of “God-given” right to make a profit in the future, whether the public likes your product (or your way of doing business) or not. And I don’t think that U.S. environmental regulations need to be business-friendly in order to be the right thing for our society to do.

The value of a clean, low-carbon-dioxide atmosphere is enormous, and it belongs to all of us, equally. I’d like to think that my Senators (this means you, John Kerry and Scott Brown) won’t be intimidated into giving it away.