An ongoing review of politics and culture

Paul Krugman. Pot. Kettle. Black.

Paul Krugman has argued in his most recent New York Times column that opponents of the Waxman-Markey energy and environment bill (a.k.a. the “cap-and-trade” bill) are dishonest when they argue that it would be expensive to implement. He starts with wisecracks about climate change deniers; in what I assume is a first for Professor Krugman, he cites the behavior of a corporation as positive evidence for the moral worth of his position; and he quotes Joe Romm’s blog complaining that opponents of cap-and-trade are constantly changing their analysis in order to support pre-determined conclusions – which for anybody involved in this debate qualifies as the only really good laugh line in the piece.

When Professor Krugman eventually gets around to addressing substance, here is his argument:

[T]he best available economic analyses suggest that even deep cuts in greenhouse gas emissions would impose only modest costs on the average family. Earlier this month, the Congressional Budget Office released an analysis of the effects of Waxman-Markey, concluding that in 2020 the bill would cost the average family only $160 a year, or 0.2 percent of income. That’s roughly the cost of a postage stamp a day.

By 2050, when the emissions limit would be much tighter, the burden would rise to 1.2 percent of income. But the budget office also predicts that real G.D.P. will be about two-and-a-half times larger in 2050 than it is today, so that G.D.P. per person will rise by about 80 percent. The cost of climate protection would barely make a dent in that growth. And all of this, of course, ignores the benefits of limiting global warming.

Professor Krugman starts here by repeating the already-hackneyed political talking point that over the next decade Waxman-Markey is projected to have the same cost as “a postage stamp a day”. He then, to his credit, proceeds to consider its projected costs by 2050, which is crucial because emissions mitigation would need to be sustained for many, many decades in order to achieve its desired climate effects. He waves his hand at a projected cost of about 1% of income. But 1% of U.S. income is an enormous amount of money. Suppose I proposed some government program, and told you that it would cost “only” $150 billion per year, every year, for more than a hundred years, and then told you that this was no big deal because it’s only about 1% of the economy? I mean, it would “barely make a dent”. His argument is absurd.

Of course, if there were a persuasive case that it would create benefits that would more than offset this cost, it would be rational to support it. What is his argument about the benefits? “And all of this, of course, ignores the benefits of limiting global warming.” That’s it? Professor Krugman has a Nobel Prize in economics – he’s got to be able to do better than that. Why doesn’t he make any attempt to justify the costs? As I’ve argued at length, even using assumptions that are extremely favorable to the bill, the expected costs of Waxman-Markey are at least ten times larger than the expected benefits to U.S. taxpayers.

Professor Krugman then concludes his column with seven paragraphs that chastise his ideological opponents for lacking fair-mindedness and intellectual rigor.

Has Global warming Stopped?, ctd.

I blame myself for what I consider to be the pretty disappointing responses to my prior post (especially the normally excellent TAS comboxes). The fact that so many people have reacted to things I wasn’t trying to say indicates that the communication failure is mine. So let me try to be clear about what I was actually trying to say.

When confronted with objections to an apparent scientific consensus, one valid approach is simply to assemble a wide variety of relevant scientists, ensure that the questions posed to them are technical questions within their scope of competence, and rely on their findings. This is the basic idea behind the UN IPCC, and the AGW reports of various national scientific academies. This has been my approach in the case of AGW, where I have always taken the technical findings of the IPCC as the starting point for any policy analysis on this topic.

George Will (or at least the view that was reasonably imputed to him by his interlocutors), questions the validity of the scientific consensus on AGW. His interlocutors, instead of just relying on the IPCC process, tried to engage the substance of George Will’s quasi-scientific objection. They responded by saying that he has not looked at a long enough trend line.

The primary point of my post was that while I agree that George Will’s (implicit) attempted falsification of AGW theory is not compelling, neither is the logic used by his interlocutors. Both logics share a common source of failure: looking for an underlying “trend” in the temperature record independent of physical causality. There is no magic “trend”, but instead a set of causal effects based on physical interactions that drive temperature. The scientific assertion made by the global climate science community is that we have built models that allow us to understand these effects with sufficient precision to make useful forward predictions. When evaluating this assertion, then, the relevant standard is not “Is the rate of warming slowing or accelerating?”, but rather “How accurately are our models predicting the rate of warming?”. That is, we should rationally care about deviation from prediction, not deviation from trend. This is why I described George Will’s (implicit) method for addressing the certainty of our scientific knowledge as “misguided”, which in addition to explicitly disagreeing with his conclusions, seems like a funny way of defending him.

The secondary point of the post was that a component of any well-structured prediction modeling process is to have model evaluation groups separate from the model-building teams that have different incentives and reporting structures, roughly analogous to a QA team for software development or fact-checkers at a magazine. One key task of such model evaluation teams is typically to escrow copies of code used to make predictions, log forward predictions made at time X for some outcome after time X, then run the code at the time of the predicted event with actual data entered for all inputs other than the asserted causal factor, and compare the resulting model output to actual outcomes. This is done across a range of predictions to create distributions of model error. While there have been some kludgey, one-off attempts to do something like this for the Hansen 1988 testimony, and a group has tried to look at single-year predictiveness of global climate models, there is nothing like a structured program in place to do this for climate models. Such approaches are always imperfect – and I tried to point out in the post some of the reasons that this would be especially problematic in the case of global climate models – but it would still provide a far better basis for the discussion of prediction adequacy than we have now.

What’s especially ironic abut a lot of the commentary on the post is that lots of people take assertions of uncertainty in climate forecasts as undercutting the case for emissions mitigation, so those on the Right argue for uncertainty, and those on the Left argue the opposite. In the sophisticated AGW debate, the economic justification for mitigation is seen as, conceptually, an insurance premium. If the expected warming takes place with expected effects, it is very difficult to justify the economic costs of mitigation, and therefore it is a hedge against much-worse-than-expected effects. Therefore, the greater the uncertainty in climate prediction, the stronger the case for mitigation – uncertainty is not our friend. So before you accuse me of intellectual dishonesty, recognize that in pointing out limitations in the current practice of climate model validation, I am actually arguing a point that cuts against my stated policy preference.

Has Global Warming Stopped?

Ezra Klein , Kevin Drum and Ryan Avent all have posts up that attack George Will’s statement that “If you’re 29, there has been no global warming for your entire adult life”. Kevin Drum describes this as “idiotic”, Ryan as “moronic”, and Ezra responds, of course, with a chart. So does the always-numerate Kevin Drum, and I’ll use his version of the chart:

The funny thing is that if you zoom in on about the last ten years, you see this:

There has not been a lot of measured warming for the last ten years.

It’s hard to dispute this. What Ezra, Kevin and Ryan are arguing is idiotic, moronic or whatever is the notion that the past ten years of data disproves the theory of AGW. Their basic argument is “sure, but look at the long-term trend”. I agree with them about the conclusion that the last ten years of raw data don’t falsify the theory (and have argued this at many times in many places), but I’m not sure any of them have thought through this question fully.

If I observe that it is cooler in New York today than yesterday, no reasonable person would take that as proof that AGW theory is wrong. On the other hand, if we had rapid growth of human population and rapid fossil-fuel-dependent economic development for the next 1,000 years with no increase in surface temperatures, no reasonable person would claim that AGW in anything like its current form had not been disproven. The question is at what point between 1 day and 1,000 years do I have enough evidence that I can reasonably reject the theory? It seems to me that you need a rational standard to answer this question before you simply call ten years “moronic” a priori.

In fact, it’s more complicated than that. If we had no warming over the past ten years (true) and lots more CO2 in the air (true) but also a huge increase in volcanic activity (not true, but posited as an illustration), this would not be evidence that AGW theory was untrue, because the models used to predict warming would have called for no warming because all the particulate matter thrown up by the volcanoes should offset the effect of the CO2. So what we are really looking for is the degree of divergence between the predictions of the models used as the basis for long-run warming predictions versus actual temperatures, in order to falsify or corroborate the operational theory that we can predict future long-run temperature impacts attributable to CO2 emissions. The rigorous version of the question then is: what is a valid falsification period for AGW models?

So, naturally we just go to the escrowed set of AGW models with their predictions made over the past 20 years or so, enter in all data for actual emissions, volcanic activity and other model inputs for the time from the prediction was made until today, and then run the mdoels and compare their outputs to actual temperature change in order to build a distribution of model accuracy, right? Ha ha. Needless to say, no such repository exists.

Almost all humans resist management and audit, and climate modelers are no exception. Because they have been so poorly managed, we have no well-structured program to evaluate accuracy, and instead must rely only on back-testing (or what among climate modelers is termed “hindcasting”). Now, this would be hard to do, for several reasons: the models (we believe) keep improving, so the accuracy of a 1988 model doesn’t necessarily tell us the accuracy of a 2008 model; there is huge signal-to-noise, so it requires several decades (we believe) to have a useful measure of accuracy, while we are being asked to make policy questions now; and so on.

But the instincts of those who are grasping for some way to hold the tools used to make temperature predictions accountable to reality in some way are sound, even if their method is somewhat misguided. They aren’t idiots or morons, they’re just not specialists, and the government they pay for, which in turn funds the model construction project, hasn’t bothered to do its job and provide the best feasible measurements of the value of these models.

Models, Models Everywhere And No One Stops to Think

Lots of bloggers have attacked my cost-benefit analysis of Waxman-Markey. The current line of attack seems to be that cost-benefit analysis is just the wrong way to think about this problem. There are, as usual, various intertwined logics for why this might be so. They all seem to center around the idea, however, that while climate science can make reasonably reliable predictions a century or two out, economic projections over this time scale are basically worthless.

While this exaggerates the reliability of climate models, I agree that they are more useful than very long-term economics models. But let’s assume arguendo that my critics are correct in the extreme, and therefore we have no ability to translate a climate forecast into an estimate of economic damages. Then, they say, we know some kind of catastrophe is coming, and it’s our duty to head it off.

There are at least a couple of huge problems with this argument.

First, all estimates of the climate impact of human-induced CO2 emissions rely on a long-term emissions forecast, which in turn relies on (i) forecasts of population growth, (ii) forecasts of economic growth per capita, (iii) forecasts for the energy intensity of economic output per capita, and (iv) technology forecasts for the carbon-intensity of each unit of economic output. That is, we can’t make a long-range climate forecast in the absence of long-range economic forecasts.

The differences in emissions across economic scenarios are not trivial. They are the basis for the UN IPCC’s scenario-based forecasting approach that leads to a difference in estimated temperature impacts by 2100 that are about 3 times larger for the highest-emissions plausible scenario versus the lowest emissions plausible scenario.

Second, if we assume that we have literally no technical capability to translate a temperature forecast to a forecast of damages, then we are forced to rely on intuition. A 3C increase by 2100 in temperature sure doesn’t sound so awful to me. Want to argue that I’m misguided, and here is this long list of awful things that will happen? We’re right back to estimating damages, and I’ll just point to what the IPCC, CBO, EPA and so forth estimate when they try to do comprehensive estimates of net impacts.

Look, I get the point that trying to forecast what our GDP will be in 2136 to within a few percent is ridiculous. It is. Further, I get the point that indefinite accumulations of CO2 in the atmosphere will eventually become very damaging. I also get the point that there is some risk that we might reach that point sooner than we think. These are all true statements.

But if they are to inform rational decision-making, they also require quantitative, not rhetorical, interpretation. When do we expect that CO2 will be how big a problem? How big is the risk that it will be worse than that? And so on. While we may legitimately criticize a specific cost-benefit analysis or methodology, it seems hard to imagine a rational approach to such decision-making that doesn’t try to envision the future world under alternative policy assumptions and assert a preference.

So, show us your alternative forecasts and provide sources and methodologies. If you choose to respond with a bunch of words describing how awful things could look, or wave your hands, you’re still making a forecast – it’s just not of any real use. False precision is one way to evidence the problem of a unwarranted assertion of certainty, but so is simply asserting that we know the damages that we should expect within some finite time outweigh the costs of some proposed program to avert them, without providing the evidence.

The forecasts of every responsible body, as I have gone to such boring lengths to show over many articles, actually make it very hard to justify any so-far proposed carbon pricing or rationing schemes based on the benefits we should expect them to produce over the next roughly 100 years. (I think the fact that my critics are mostly attacking the idea of cost-benefit analysis itself, rather than my quantitative arguments, is pretty good evidence of this.) Eventually, of course, if we assume linear extrapolation of current trends, CO2 will become a deadly problem; but I think if you’re honest, you’ll find yourself having to justify these programs based on things that you project will happen in the 22nd century and beyond. Who’s being arrogant about predicting the future now?

I have very little idea what the technological, social and political bases for the human economy will be hundreds of years from now, and think that trying to manage such a problem by changing carbon pricing today is foolish in the extreme.

Money is Not the Measure of All Things

I think there is a compelling case that if we were to use the best estimates from the IPCC and similar technical bodies for the most likely impacts of Anthropogenic Global Warming (AGW) on average global GDP over the next century, then proposed programs of emissions mitigation are not economically justified. Many very smart bloggers have made the point that that using average global GDP as our only metric to evaluate the relative attractiveness of potential future outcomes misses a lot of what should be important to us.

I believe that there at least two intertwined strands to these objections:

1. Average GDP misses a lot. We could wipe out the GDP of many poor countries, and still only have a small impact on global GDP, and it doesn’t seem fair to consider lowering U.S. GDP by a fraction of 1% on one hand, and entirely eliminating the country of, say, Bangladesh on the other, as equally bad in some important moral sense.

2. GDP misses a lot. There are many things that we care about that are not captured in GDP statistics, such as human health or suffering, maintaining traditional ways of life, aesthetic beauty and so on.

I’ll try to address these one at a time. I’ll rely heavily on papers by Indur Goklany in which he integrates multiple analyses, predominantly from the IPCC and the UK government.

1. Relative economic impacts on the developing vs. the developed world

There is some trade-off between economic growth and mitigation of AGW damages, at least in the short-term. Mitigation advocates often correctly point out that the global poor will be disproportionately affected by AGW damages, but it is also the case that they will be disproportionately affected by reductions in global economic growth. An empirical question is the relative size of these two effects.

Consider Goklany’s review of research that compares the change in climate and wealth under various UN IPCC scenarios for development over this century. I’ll show the two extreme scenarios to make a point: A1F1 (the IPCC scenario for global development that is most heavily dependent on fossil fuels, and has a projected increase in global temperature of about 4C by the end of the century), and B1 (the scenario that assumes greatest deployment of alternative technologies, and has a projected increase in global temperature of about 2C by the end of the century). Here are the projections for each scenario for the developed then the developing worlds:

Developed Countries Projected GDP / Capita in 2100:

A1F1: $107,300 B1: $72,800

Developing Countries Projected GDP / Capita in 2100:

A1F1: $66,500 B1: $40,200

In other words, at least through the next hundred years, the average person living in the developing world is better off in money terms with more economic development and more AGW damage, on net. A lot better off in fact: $66,500 is more than 65% higher than $40,200.

I’ll note in passing that by 2100 the average person in the developing world is projected be at a level of income comparable to the U.S. in 2009.

2. Impacts not directly captured by GDP

I’ll focus first on two items which any reasonable analyst would consider to be important, and for which we have some projections: hunger and water.

Goklany has collated detailed projections for the projected change in various metrics between a baseline year of 1990 and a projection year of 2085 from the UK Government’s Fast-Track Assessment of global climate change (FTA). This is a 95-year projection, and as there should be some acceleration of warming effects this should be a tolerable estimate for impacts for the highly-overlapped 91-year period from 2009 to 2100.

Here are the results for projected humans at risk from hunger under the A1F1 versus B1 scenarios:

Under either scenario, the world should be able to push those at risk for hunger down to 1% – 2% of the world’s population by the end of this century, at any projected level of warming. The realistic risks to this are war, other political action, or threats to a world of interdependent trade and economic growth. The impact of global temperature change is rounding error in comparison.

Here are the results for humans at risk of water stress:

Because wealth allows us to insulate ourselves from environmental risks, a warmer but richer world is projected to be better off on this metric.

Here are some other metrics. The percentage of the world’s population that is at risk for coastal flooding is well under 1% in the baseline, and is not projected to rise close to 1% in any scenario within the 95-year forecast. Malaria deaths have historically been in effect eliminated by societies that achieve several thousand dollars per year of per capita income – the key risk here is once again slower economic growth that keeps parts of the developing world poorer longer.

Again and again, we see the same pattern: at least for the next century, changes in human welfare, even on metrics that are not purely economic, are fundamentally driven by changes in economic development, not AGW damages. This is why it makes sense to be focused acutely on risks to economic growth when considering the overall effects of any emissions mitigation program.

What Are The Stakes in The Climate Change Debate?

Here is one straightforward way to put this in perspective.

1. Let’s start with a very long-term and global perspective of total present value of expected global income over the next several hundred years.

2. Then, estimate the total expected present value of damages expected to be casued by Anthropogenic Global Warming (AGW) over this period.

3. Then, estimate how much of these future warming damages we could avoid at a cost less than the avoided damages, assuming a globally-harmonized, optimally-designed and optimally-executed emissions mitigation program (say, a global carbon tax).

4. Then, subtract the expected costs of this mitigation program from the expected future avoided damages to come up with the bottom-line estimate of the expected net present value of the best-possible emissions mitigation program.

Using Nordhaus’s canonical analysis, here is what these four numbers look like:

The total net expected benefits of the best-imaginable program to combat global warming are about $3.4 trillion. This is about 0.17% of the expected present value of total global income.

Compare the current Waxman-Markey bill to “an optimally-designed and optimally-implemented” carbon tax. Consider what it would be like, in the real world, to cut a global deal. Now consider what it would be like to enforce this for more than a century, not only in Sweden, Japan and Australia, but in China, India and Brazil. Compare this to “a globally-harmonized, optimally-designed and optimally-executed emissions mitigation program.” Do you think the economic drag the real-world deal would create might cause the planet to lose more than 0.17% (or for that matter, 1.7%) of the present value of future income as compared to the case without such a deal? It is extremely likely, in my view.

Numerous very intelligent bloggers have raised the valid point that global GDP, or any measure of money income, is not a comprehensive measure of human well-being. I’ll have a future post on this topic. But it is striking that, at least when looked at in terms of the economy, we should expect the benefits of emissions mitigation to range from losing money (my view) to a positive gain of 0.17%, assuming perfection.

The problem is that we’re putting a global economy with present value of $2,000 trillion at risk to go after less than $4 trillion of expected present value of benefit. The desire to regulate the global economy to avoid the risk of catastrophic climate change is not a one-sided bet.

Re: What's The Point?

Almost exactly a year ago I wrote a post in which I tried to predict the course of the climate change debate. In it I said this:

Given current projections, the costs of restricting emissions just can’t be justified based on the benefits that it is projected to provide.

As far as I can see, proponents of emissions reductions will respond with four arguments: (1) inflate the analyzed costs of global warming by claiming the science actually now says things will be even worse than we previously thought, (2) inflate the analyzed costs of global warming by embedding indefensible discount rate assumptions in the black box of econometric calculations used by economists to conduct the cost-benefit analysis, (3) deflate the analyzed costs of emissions mitigation by claiming a free lunch – that there is a cost-free or low-cost way to radically reduce emissions, and/or (4) turn this into a moral crusade asserting that we have a moral duty to the poor of the world because of our past sins of emission. I have laid out responses to each of these objections: 1, 2, 3 and 4. When considered carefully, emissions mitigation proponents have no persuasive arguments.

Conor Clarke has a written a post in which he manages to combine two of these arguments at once.

Claiming the science actually now says things will be even worse than we previously thought? Here’s Conor:

It’s possible to quibble with Manzi’s data. (More recent temperature estimates than the IPCC’s exist: You can check out the work of MIT’s Joint Program on Global Change for more.)

Check.

Turn this into a moral crusade asserting that we have a moral duty to the poor of the world because of our past sins of emission? Here’s Conor:

The big costs of global warming will fall overwhelmingly on developing nations with dense, coastal populations. You can be a realist about those costs — why on earth should America care what happens to Bangladesh? — but the costs are still real. They are also, by and large, not costs for which the developing world is responsible.

Check.

The thing is, I agree that these are significant considerations – they’re just not as obvious as Conor asserts they are, and I think a useful analysis of the problem requires confronting the strongest arguments around both issues. I’ll just start by referencing the counter-arguments from my earlier post. And before anybody gets on a high horse about how CO2-laden economic development is such a threat to the poor of the developing world, he really ought to have a response to this analysis.

Re: How Much Would You Pay for Cap-and-Trade?

Derek Thompson has a post up which reproduces Nate Silver’s graph estimating that the break-even price for the average American to support solving AGW is about $19 per month, or not much more than CBO and EPA estimates for the costs of Waxman-Markey through 2020. This is almost certainly an accurate representation of polling reesponses, as it is closely consistent with the results that an MIT group has gotten for five years or so as they have nationally-represnetative polling on a very similar question.

However, here are a couple of severe problems with the implications of this post:

1. The most obvious is that responses such as this to a pollster, or commercial survey, are notoriously inaccurate predictors of behavior.

2. The more fundamental is that Thompson and Silver compare this response to the CBO projection of costs for Waxman-Markey as of 2020, which is many decades prior to the point at which it would even theoretically create significant benefits. In order to actually achieve its goals, it would have to be in place for many, many decades. By that point, its costs would, according to the EPA and any other competent analyst, be far higher, in absolute and % of income terms.

The Visual Display of Quantitative Information II

Conor Clarke accepts that:

I think Jim Manzi and others are right to say — if you believe the IPCC and CBO — that the U.S. won’t experience a climate-induced decline in GDP until 2080 or 2100.

But Conor goes on to argue that the costs that Waxman-Markey is expected to impose on American consumers by 2050 – about $1,1,00 per household per year, or a little less than 1% of total consumption – are pretty trivial, because we should expect to be so much richer by then. (I’ll note in passing that, as per my posts on this, there are very good reasons to believe that the EPA cost estimate is low, and also that costs are also virtually certain to rise between 2050 and roughly 2100 when we would expect to start getting some offsetting benefits.)

He then shows a chart making the point, basically, that 1% is a small fraction of 100%. But of course, this cuts both ways. We hear constantly about the existential threat posed by global warming – Cities underwater! Drought! Famine! Think about his graphic. The expected benefits don’t even outweigh these costs. That ought to make you stop and think.

But, you might say, that is because we are taking a parochial view that only looks at the U.S. and only the next several decades (which is a pretty broad definition of parochial). We need to consider our actions as stewards of the entire planet over at least a century. OK, let me do a very simple chart for you, built from a list of simple, validated assumptions:

1. Secular long-term global growth in real per capita consumption before considering any effects of global warming is about 1.3% per year. (This is a standard conservative estimate; it has averaged about 2.5% per year over the past half century).

2. Unrestricted global warming produces a global temperature change of 4C within a hundred years (which is quite aggressive, a better middle-of-the-road estimate is about 3C).

3. Economic damages from this temperature increase are equal to 5% of GDP (which is the top end of IPCC’s estimated range for 4C of warming).

The following chart shows what income an average person on earth has today, plus the same number in constant dollars for (i) 2110 with unrestricted global warming, and (ii) 2110 if we somehow magically eliminated all damages from global warming for the entire world at zero mitigation cost, labeled “2110 w/ no AGW”.

The expected impacts of human-induced climate change are marginal as compared either to the sloppy, sentimental and self-righteous rhetoric that surrounds this issue, or as compared to the potential reduction in global material well-being that would likely be created by ham-fisted attempts to substitute political allocation of resources for markets.

Dear Member of Congress: Why You Should Vote Against Waxman-Markey

It appears that years of debate about climate change and energy may now come down to a vote on an actual bill, the American Clean Energy and Security Act of 2009 (ACES). As I write this, the vote is scheduled for Friday. If it occurs, you will be asked to vote to implement carbon rationing in the United States.

Without regard to party or ideology, I believe that the evidence is clear that this law would be contrary to the public interest. Here is why, in a nutshell:

1. It would be a terrible deal for American taxpayers. According to the Environmental Protection Agency, it is projected to impose annual costs of about $1,100 per household (a little less than 1% of total consumption) by 2050. The benefits we will get in return? If the law works precisely as intended, in about one hundred years we should expect surface temperatures to be a about one-tenth of one degree Celsius lower than they otherwise would be. The expected costs are at least ten times the expected benefits, even using the EPA’s cost estimates and assuming achievement of the primary goal of the legislation.

2. The argument that “OK, it’s a terrible deal standalone, but we need to lead the world by example” is extremely unconvincing. First, while you are probably not a climate science expert, I bet you’ve negotiated a few things in your life. What do you think about the negotiating strategy of unilaterally giving away our most obvious leverage – namely “we’ll reduce our emissions if you reduce yours” – and instead hoping that those nice men who rule China will be guilted into sacrificing their perceived economic self-interest if we just go first? Second and more fundamentally, as per many detailed analyses, the global deal that we would theoretically be chasing isn’t even attractive, even if we assume every technical climate change prediction by the UN IPCC is correct.

3. Contrary to early expectations that auctioning cap-and-trade permits would generate $80 billion per year of government revenue, this law would not contribute materially to deficit reduction. You’ve seen the internal negotiations up close. Because so many allowances have been given away to special interests to try to get the votes needed to pass ACES, the CBO now estimates that it will bring in a net of a little over $2 billion per year over the next decade. As you know, this is about one one-thousandth of this year’s budget deficit.

4. A further effect of all of these deals (which are entirely predictable in a democracy) is that ACES is very unlikely to achieve even the limited benefits that are claimed for it. The details of the bill mean that there is now not a hard cap on emissions for at least the first decade of its existence. What do you think the odds are that this will change at some undetermined point in the far future when all of the normal interest group pressures of a democracy are supposed to magically disappear?

5. In short, Waxman-Markey would impose costs at least 10 times as large as its benefits, would not reduce the deficit, and doesn’t even really cap emissions.

(cross-posted to The Corner)

Prediction Model Bias

Brad Plumer provides a very practical reason why he believes environmental cost predictions tend to be over-estimates:

[M]arkets always tend to be smarter than these forecasters, and adjust in ways that no one expected.

Let’s assume arguendo that this is correct (and I think it is, as a general statement about markets vs. planners – I’m about as Hayekian as they come). This leads to two questions, one far more important than the other.

1. The narrow point is that, per prior discussion on this, if one could actually observe a reasonably consistent over-estimate in a provably-relevant reference class of prior predictions, this would lead a competent forecaster to make a transparent “topside” adjustment to get a best-available forecast.

2. The more important point is that this same logic ought to apply to the damage estimates that similar bodies forecast for the costs of climate change. That is, markets should be smarter than forecasters think when it comes to adapting to climate change as well (e.g., crop selection, transitions to other economic sectors, clever infrastructure developments and so on). To only focus on this kind of error on one side of the cost / benefit calculation is loading the dice.

Climate Change Back-and-Forth

I’m glad to see that Megan McArdle is confronting the reality that Waxman-Markey is very unlikely to work, either in the sense of providing benefits greater than costs, or in the sense of achieving anything like its stated goals, even without regard to cost.

I’m also glad to see that Ezra Klein is explicit about his acceptance that climate change is expected to have extremely limited effects on the United States for at least the next hundred years. I figure that ought to be pretty important when debating the proper policies for the government of the United States. On the other hand, we continue to disagree about the financial efficiency of the foreign aid program defined by transforming the energy sector of the American economy in order to very slightly ameliorate a predicted problem that might affect people who might live in low-lying equatorial regions of the world decades from now.

Ryan Avent, on the other hand, refuses to see the light. If you want the background to this post, there is Ryan, me, Ryan, me, and now this one from Ryan. This will be my last turn at bat on this one.

In his latest reply, Ryan starts with this:

One thing that recurs in Manzi’s writing on climate change issues is an extreme devotion to the infallibility of models.

Here is what I said in what I’m pretty sure is the first thing I ever wrote for publication on climate change:

Over the past several decades, teams in multiple countries have launched ongoing projects to develop large computer models that simulate the behavior of the global climate in order to account for feedback effects. While these models are complex, they are still extremely simplistic as compared with the actual phenomenon of global climate. Models have successfully replicated historical climates, but no model has ever demonstrated that it can accurately predict the climate impact of CO2 emissions over a period of many years or decades.

Climate models generate useful projections for us to consider, but the reality is that nobody knows with meaningful precision how much warming we will experience under any emissions scenario. Global warming is a real risk, but its impact over the next century could plausibly range from negligible to severe.

In fact, I think it is fair to say that the idea of uncertainty in our predictions has been central to my entire argument on climate change from the beginning.

Ryan goes on to criticize my point that if we really have a track record of consistent prediction error, competent modelers should be able to incorporate that information into forward predictions:

Just because Doug Elmendorf can probably say that he’s going to overestimate the costing of Waxman-Markey doesn’t mean that he can say where and by how much, with the level of methodological surety necessary to allow him to include an adjustment of some sort. Manzi seems to convey the idea in his work that such a state of affairs ought to render a piece of information unusable, or irrelevant. But that’s a strange way to approach a problem — any problem.

Sorry, that’s not a strange way to approach prediction at all. If I make a string of 100 predictions using method X for how many runs the Mets will score in their next game, and my prediction is always exactly one run low, it would likely be intelligent to modify my method to be whatever X produces plus one run. The complexity, of course, is that I’m not always one run low, but I’m one run low on average. More fundamental is the reference class problem in such an adjustment: is it that my model tends not to work as well for home games, or is it games on weekends, or is it games in which Y pitches and so on. This is the substance of the nerdy debates about predictive modeling.

If you look across his posts on this topic, Ryan is trying to argue three things simultaneously: (1) we should take this cost forecast as important because the CBO produced it; (2) there is an unambiguous track record of environmental cost over-prediction which is simple enough that as consumers of this prediction we can reliably reduce the CBO forecast by some non-zero amount; and (3) the CBO failed to use this information in producing their forecast. Sorry, I’m not buying. I agree that there is lots of uncertainty around any such forecast, not that there is a sufficiently reliable forecast bias that we should treat this as an inherent over-estimate.

Ryan goes on to say:

You see this with his discussion of cost-benefit analysis in general. People say to Manzi, well, what if the predictions are off? Manzi replies, but of course, the modelers have thought of this and have built probability distributions to include all these difference possibilities, so when you ask “what if they’re off” you’re really asking “what if something happens that’s outside the distribution,” which means you’re just invoking the precautionary principle, which is daft, etc.

This paragraph is pretty accurate, other than the last part. It’s not true that I’ve equated worrying about the danger of “something outside the probability distribution” with “the precautionary principle”. I have consistently characterized the idea that climate change damages could be worse than the worst-case scenarios projected by the IPCC as a real danger, but argued that we must set this in the context of other dangers, and consider the costs of trying to forestall it in comparison to benefits. The precautionary principle, on the other hand, goes far beyond recognizing the realistic possibility of such an outcome, and instead proceeds all the way to the fallacy of the one-sided bet: the idea that we should bear almost any cost in return for almost any reduction in the expectation of such an outcome.

Nice Try II, ctd.

Ryan Avent responds to my post with a list of six objections. I’ll try to take each in turn:

First, it’s news because it’s the CBO.

Fair enough. A second organization has confirmed a cost estimate already produced by the EPA. A cost estimate, by the way, which was incorporated into a cost/benefit analysis at TAS that shows a very poor payout for Waxman-Markey.

Second, the cost overestimates have nothing to do with any underlying issue bias; as Brad Plumer notes, those favoring and opposing regulations both historically overestimate costs.

Presumably the same awareness of the track record of asserted prior under-estimation of environmental costs was available to both the EPA and CBO as they prepared their cost estimates. Unless we wish to assert that they are biased or simply irrational, why would we assume they failed to incorporate this information into their (very similar) forecasts of costs by 2020?

Third, the EPA report estimates a net present value cost of the legislation in 2050 at between $140 and $180 per household.

Not disputed, but also incorporated in and not contradictory to the prior cost/benefit analysis. Be wary of the counter-intuitiveness of present value calculations that are conducted over many years.

And fourth, these estimates don’t include the benefits of reduced warming.

Not disputed, but also incorporated in and not contradictory to the prior cost/benefit analysis.

And fifth, even Manzi’s stated cost is below the bunk cost estimates GOP legislators throw around.

Also, not disputed, at least in some cases. But, again, not contradictory to the cost/benefit analysis.

And sixth, Manzi still thinks we have no obligation to reduce our emissions, even though the costs associated with our carbon output will overwhelmingly be felt by the global poor, who are least able to do anything about it.

That’s not exactly true. I do not believe that we have an unlimited obligation to do this, as per numerous prior posts on this topic here at TAS.

Nice Try II

Kevin Drum, Matt Yglesias, Ryan Avent and Ezra Klein all point to a recent CBO report that predicts the cost of Waxman-Markey to an average American family will be about $175 per year by 2020 as news. And further, as news that undermines any claim that emissions abatement will be more than trivially costly. Messrs. Ygelsias and Avent did follow-up posts asserting that this is likely a gross overestimate of the costs.

First, this isn’t news. As per my post of about a month ago (helpfully titled “Waxman-Markey Cost Benefit Analysis”), this is consistent with the earlier EPA cost prediction of about $160 per household per year by 2020. Technically, the new CBO prediction is about 10% higher.

So what’s the problem? Doesn’t this mean that opposition to Waxman-Markey on cost / benefit grounds is blind and uniformed? The problem is that achieving the benefits of Waxman-Markey would require that the emissions abatement continue long, long past 2020. Costs will continue to rise decade after decade. The same EPA report projects that the average cost per household will be about $1,100 per year (equal to a little less than 1% of total economic consumption) by 2050. That’s according to the EPA. Who I’m sure are grossly over-estimating the costs of environmental protection, just like those other anti-environmental crazies at the CBO.

Nyet So Fast

Kevin Drum, someone I have always considered to be an exceptionally smart and sensible blogger (for Mother Jones!), criticizes my recent post on Waxman-Markey, saying that the reason the Democratic sponsors are being held hostage by their fellow party members representing midwestern and mountain states is that:

Republicans have cynically decided nearly en masse to blindly oppose any action on climate change whatsoever.

But why is this opposition “cynical” and “blind”? What if it’s “principled” and “informed”?

I’ve tried to lay out why I think there is a principled, informed case for opposing Waxman-Markey in some detail in a post that the one Drum references links to. Drum says that he takes “a more generous view of Waxman-Markey than Manzi”, but it seems to me that a whole lot turns on who is right on that question.

The Deep Cynicism of Waxman-Markey

I’ve written a lot about why I believe that even if one accepts that Waxman-Markey will accomplish its stated goals for greenhouse gas emissions reductions via a cap-and-trade mechanism, it would still be a very bad law.

At a practical political level, as far as I can see, the fulcrum of the debate is among midwest and mountain state Democrats. The Republicans (excepting the senators from Maine) seem solidly against it, and most coastal Democrats solidly for it. The legislative strategy appears to be to cut whatever side deals are necessary to get the swing Democrats to support it. This mostly has meant giving away special allowances and spending programs to pretty much every industry or region that actually produces greenhouses gasses at sufficient scale to play the lobbying game.

There does not seem to be any line in the sand that they will not cross. At this point, the side deals seem to have consumed the cap. That is, when you look under the hood, there is not really a material binding cap in this bill for at least a decade. Nothing is left but the political rents. This is basically why the CBO now estimates that all those net revenues from auctioning ration cards that were going to help offset our structural budget deficit are not going to be there. In fiscal terms, Waxman-Markey will bring in almost nothing. We’ve given it all away.

Informed activists look to the various clean air and water acts, and argue by analogy that we just need to get the structure in place, and then over decades, as with those bills, work the courts, staff the regulatory agencies with true believers, pass occasional amendments in Congress and so forth, in order to tighten the limits. This logic is an extension of the “We need this deal, even though it looks terrible on a standalone cost-benefit basis, so that we can get the rest of the world to go along with binding caps” to something like “We need to pass an ineffectual law to set up a structure that over time can be used to create an effectual law that is still terrible on a standalone cost-benefit basis, so that we can then use this to persuade the rest of the world to go along with binding emissions caps”. Talk about your bank shots.

But beyond this, I think this analogy is mistaken. This is less like the Clean Air Act than it is like a new corporate income tax. It comes with a set of powerful rent-seeking entities with strong incentives to keep very high theoretical rates in place, while carving out exemptions for themselves. It’s hard to imagine a structure better designed to reward lobbyists, large industries and members of Congress, and less likely to efficiently reduce greenhouse gas emissions.

Discount Rates and Academic Mau-Mauing

Will Wilkinson ably takes on the idea that economists have a whole lot to say about what discount rates should be used in comparing costs and benefits in the debate over global warming. I have a more aggressive take: I dispute that we should care about discount rates, per se, at all.

Let me start with a stylized example to illustrate why. Suppose you were presented with two alternative policies to deal with global warming, A & B. A is roughly speaking, do nothing, and B is roughly speaking, a stiff global carbon tax. Let’s further assume that scientists, agronomists and so forth have constructed a good estimate for the GDP of the planet for each year 2010, 20011, and so on out to, say, 2260 (i.e., 250 years from now). That is, you have for policy A a list of 250 numbers, each of which is the projected global GDP for each year; and you have an analogous list for policy B. Let’s further assume that global GDP over the next 250 years is all you care about, and that these are the only two options. You are emperor of the world. How would you decide which policy to pursue?

One way to do this would be to create a “discounting function”, of greater or lower complexity, that can be applied to any list of GDP estimates by year to generate one number, the present value of this list. You could apply this discounting function to the list of projected GDPs for options A and B, and then choose the policy that has the higher present value. Alternatively, you could simply look at the two lists of GDP projections for policy A and policy B side-by-side, and choose the one that you think is better. In the example given, I would always employ the second method.

Why should I believe that there is any discounting function relevant to global warming that exists in closed form? I have a set of preferences for comparing current to future scenarios of projected costs vs. benefits. Much of the knowledge that informs this set of preferences is tacit and/or contingent on elements of the scenarios that I didn’t list comprehensively in advance, but react to as I am presented with specific scenarios. This is of particular practical importance in a case like global warming which operates across a scope – centuries of time across the globe – in which many of the embedded assumptions that I use when making discounting assumptions in day-to-day life will likely be violated. If an economist can’t find a function that encompasses these, I’m not necessarily irrational; the economist just can’t model my beliefs in a way that he finds convenient. The discounting function is merely a heuristic, not some straightjacket that I have agreed to be bound by just because I haven’t disputed its assumptions.

The primary practical use for these discounting functions in global warming analysis is to have a function that allows integrated environment-economics models to search a wide space of possible policies automatically with a commonly-applied set of explicit assumptions without requiring human intervention to consider each model run. When it comes time to look at the policies that the model says are best, I would always want to see the actual data by time period for a variety of “good” scenarios to determine what policy I think makes sense.

Think of these models as being like a Google search. With infinite time and patience, I could review every document on the Web, but I have only finite time. The Google PageRank algorithm imperfectly, but usefully, narrows down the number of documents I need to review; usually, however, I don’t use the “I Feel Lucky” button, and certainly would not in a case where my life depended on it.

Yet More on Waxman-Markey

Ryan Avent has criticized my take on Waxman-Markey at The Atlantic, so I have responded at the same place. He raises some points that some TAS commenters have as well, so I thought I would link to it here. And also becuase nobody is bored of this yet.

The Emperor's New Cap-and-Trade Clothes

Patrick Appel at The Daily Dish has put up two more responses from readers to my post on costs and benefits of Waxman-Markey.

I’ll focus first on one important point that they both made. The first says:

[W]e all understand that if China and India and all the other big emitters stay on sidelines, it is wasted effort. So, the stated “benefits” of Waxman-Markey, looked at in this way are of course near zero.

The second says:

Manzi is largely correct on his central point: Waxman-Markey’s emissions targets, if adopted only by the United States, will likely lead to a net economic loss for the United States, because the avoided temperature increase will be so small.

So before we move on, let’s note that my critics all seem to agree that if Congress passes this law, and we do not subsequently get agreement by the rest of the world (i.e., parties that Congress can not compel) to also reduce emissions, then the Waxman-Markey bill will create net economic losses for the citizens of the United States. Apparently everyone already knew this, but I guess I like to emphasize the obvious.

The first correspondent goes on to say:

…not all leading economists working on this issue think it will cost a lot (in terms of economic impacts). It won’t be free, but it is not going to drag the economy down. Every analysis I’m aware of shows some reduction in overall economic growth of at most a percent or two – the baseline continues to grow. So rather than being 100% wealthier by set date, we are only 98 or 99% wealthier.

I provided a link to specific present value calculations for this trade-off under the assumption for global agreement in my post. I guess if you want to wave your hands and say that “a percent or two” of U.S. economic growth is no big deal, you’re free to do so. I think that’s a whole lot of money.

The second makes explicit the point that the essence of this proposal is to impose large economic costs on American taxpayers for the sole purpose of providing a negotiating advantage in getting the rest of the world to do the same. He starts by saying that if we could structure such a global deal that I would agree that “it looks pretty god”:

However, if W-M becomes a model for the rest of the world, it starts to look pretty good, even by Manzi’s own standards.

This is not correct, at least by “Manzi’s own standards”. As per the first several paragraphs of my post, I believe strongly that such a global deal would not create expected net benefits for the world as a whole, never mind for U.S citizens. I won’t repeat that entire part of the post, but will just refer back to it. This correspondent suggests my “own math suggests I’m wrong”. He doesn’t explain why this is so, other than by referring to somebody else’s analysis. Once again, I linked directly to the research document that substantiates my claim that the global NPV benefits of an optimal emissions mitigation program has an expected value equal to 0.2 percent of future global consumption. As far as I can see, this analysis remains unchallenged. My argument is that we will never have such an optimal system in the real world, and that economic drag created by non-optimality will create costs that are much larger than 0.2% of future consumption. This argument also seems to me to be unchallenged. The fact that another party has done some other calculations that I have not reviewed, endorsed or deployed doesn’t really seem to me to address this argument.

So let’s review the overall bidding, at least as I see it:

1. Everybody agrees that if Waxman-Markey becomes law, and it does not lead to a global, binding and enforced agreement to severely reduce global greenhouse gas emissions, then it makes U.S. taxpayers worse off economically.

2. I have presented an economic argument that even if such a global agreement were achieved it would accomplish in the best case a net increase in NPV of global consumption of 0.2%, and a practical argument that it would almost certainly reduce global economic welfare. These specific arguments remain undisputed.

3. Those who argue that Waxman-Markey would lead to a global agreement have provided no evidence that it would have this negotiating effect, and are presenting what is, at best, a pretty idiosyncratic negotiating premise that by giving away our leverage as one participant in a collective action problem we will somehow increase our ability to get others to sacrifice on our behalf.