Env-econ has a go at the “sunspots cause warming” theory.
The Dyson Critique (the Lucas Critique for the macro-climate) says that climate models that assume constant feedback effects with the increase of CO2 are unreliable predictors of climate change. Here’s another great discussion of the issue:
If that is not enough, changes in CO2 in the real world would almost certainly be associated with other changes in the atmosphere – sulfur dioxide, mineral aerosols (dust), ozone, black carbon, and who knows what else would vary through time and complicate the “all else held constant” picture. By the way, the Sun varies its output as well. And when discussing climate change over the next century, even more uncertainties come from estimations of economic growth, adoption of various energy alternatives, human population growth, land use changes, and … you get the message.
He goes on to say there have been recent estimates of, what economists would call, the reduced form parameter — the sensitivity of the atmosphere in terms of temperature increases to increasing CO2 levels. Basically, by looking at levels of atmospheric dust, and their correlation with CO2 levels, during previous warming periods, scientist were able to estimate the reduced form parameter. He reports that their conclusion is that climate sensitivity is lower than previous estimates which means we should expect less warming than previously estimated.
There is no discussion, however, of what economists call the structural parameters. Why is there a connection between CO2 levels and dust levels, for example? If there’s a third force that is driving both CO2 levels and dust levels, then its not clear the new estimates of sensitivity are applicable to the climate today. My understanding is that in the past, CO2 wasn’t driving climate change, climate change was driving CO2 levels and CO2 was acting as a positive feedback. The earth warmed, the ocean’s emitted their stores of CO2 causing further warming. Given the climate didn’t become unstable, I assume there were also negative feedbacks that brought the system back into equilibrium.
Its not clear though that those negative feedbacks had anything to do with CO2 levels. The pertinent question then is: can historical data tell us anything about the climate feedbacks from increasing CO2 levels today?
Alex is the quiet half of the MR blog, but he usually makes up for his low quantity with high quality. His most recent post, The Law of Unintended Consequences, is in response to this post at the Freakonomics. Alex comes up with this definition for the Law:
The law of unintended consequences is what happens when a simple system tries to regulate a complex system. The political system is simple, it operates with limited information (rational ignorance), short time horizons, low feedback, and poor and misaligned incentives. Society in contrast is a complex, evolving, high-feedback, incentive-driven system. When a simple system tries to regulate a complex system you often get unintended consequences.
The Law should make us hesitate to invoke the so-called Precautionary Principle that I wrote about a couple years ago. The Principle would have us do “something” about climate change because even though there’s great uncertainty about the science of climate change, there’s a substantial chance of great harm if we do nothing. The Law, though, pushes back on the idea of doing “something” by suggesting that “something” will have unintended side effects.
The NYT piece also got this reaction from Andrew Gelman and someone over at his place has this great take on the Law:
I usually think of the law as a normative one: if you propose a policy to do X and use only the direct consequences of X to motivate your decision, you will have overestimated the effect of X by ignoring indirect effects. The reason the expected effect is always counter to the direct effect is that the economic incentives must work in the other direction — otherwise you wouldn’t have needed to impose X in the first place. Thus, the ingenuity of people attempting to follow the economic incentives underlying the problem will always frustrate, to some extent, the direct effect of what you’re trying to do.
The Law suggests anything we do can have significant negative side effects. For whatever reason, incentives are aligned in the economy towards emitting lots of green house gases. Unless we address all of those incentives directly, Andrew’s commenter suggests we expose ourselves to the potential for negative unintended side effects.
How to address incentives directly? Balance policy towards pricing green house gas emissions (e.g. CO2 tax) and away from regulations (e.g. CAFE standards).
BTW, I don’t think Quiggin is clear on this point: he’s not saying that “we” ((You like those quotes Gabriel?)) have to pressure airlines to upgrade their fleets or “we” have to start planning fewer but longer vacations. He’s saying that more expensive fuels will make airplane trips more expensive. Period. Full stop. Now, because prices happen to be powerful motivators, this *could* induce fleet upgrades or changes in vacation frequency/durations. His point in the end, though, is that these changes in behavior don’t have to be that drastic and they won’t be nearly as drastic as you might expect with the scary sounding “75% decrease in CO2 emissions”.
So fuel price changes induce not-so-painful behavior changes. What causes the fuel prices to go up?
“We” ((Isn’t this the same “we” as the one above?)) institute carbon taxes in one form or other.
I was at my new book club this weekend talking about Aristotle’s Metaphysics. He makes the argument that if we are to truly understand something, then it must only have a finite number of causes.
These sorts of arguments always bug me. Infinity is big, but finite and large can be very big, too. So mathematically, these proofs seem to say something, but in reality? Its not very satisfying to know that to truly understand something I need to know its 1,978,497,902 causes…
Anyway, the other day I was saying that just because we need to do something about global warming doesn’t mean that we should do everything. This was just me being too clever like Aristotle — the argument, while true, doesn’t get us anywhere.
The important questions are being asked by Tyler Cowen:
- Policy recommendations are extremely sensitive to the choice of discount rate, and economists do not agree on this issue. Furthermore most economists do not even know enough moral philosophy to understand the issues involved (and the philosophers don’t understand enough economics), so there is no coherent consensus one way or the other. ((In other words, how much less do people value the future than today? How much should they?))
- … Martin Weitzman… argues that the very high costs of the worst-case scenarios suggest an insurance-based case for significant worry…
- We spend too much time wondering about what is “most believable” and not enough energy worrying about the expected value of pending losses…
- Given that the value of risk is context-specific, economists are bad at taking the value of insurance from market data in one setting, and then transplanting that estimate to another setting.
- The strongest argument against significant action is not from cost-benefit analysis in the narrow sense, but simply that we are not very good at producing international public goods…
I enjoy Gristmill very much in a they’re-almost-always-saying-stuff-that-makes-me-mad sort of way. My favorite writer is David Roberts and instead of subscribing to the torrent of posts found at the site, I subscribe just to his posts ((BTW, this is a feature every multi-author site needs to have… Crooked Timber? anybody, anybody?)).
He has two posts today that caught my fancy. In the first, he thinks its “funny and kind of awesome” that a new speech restriction in Norway disallows using words like “green” to describe cars. I write in a comment:
Is this funny (and awesome) because it says everything about what’s wrong with the absolutest green movement?
If a car is whisking Al Gore around in order for him to convert people to environmentalism, is it not doing any good for the environment?
The optimal level of pollution is not zero and the perfect is the enemy of the good. These may be cliches, but that doesn’t make them untrue.
Its so easy to glide from advocating changes in the extensive margins to suggesting changes in the intesive margin. That “something” needs to be done, doesn’t mean the extreme must be done.
What always amazes me is that the very same crowd that spent years denying that climate change existed, and then denying that human beings cause it, and then denying that it would be a bad thing … these very same people bring every new argument to the table with a harumphing air of solemnity, because they are, by their own estimation, the Serious People.
But how stupid and mendacious do you have to be, for how long, to finally lose credibility? How many times do we have to hear these clowns out, and furrow our brows, and stroke our chins, only to conclude yet again, “nope, sorry, you’re still a tool”? How long do proven, documented fabulists and dimwits get to define what’s “reasonable”? Enough already.
Because one side has convinced the other side that something must be done about global warming doesn’t mean the other side is convinced that a whole lot needs to be done. As a commentator on the thread, carboncat, says:
“We should leave a much larger safety margin than not caring at all.”
this is a very common argument about climate change: we should act, because the consequences are so severe if it turns out to be true.
This logic is identical to Pascal’s wager. He said that you’re better off believing in the Christian God, because if you’re a Christian and you’re wrong, you meet the same fate as everyone else (nothing is lost), but if you’re an atheist and you’re wrong, you burn in hell. Therefore, you’re better off being a Christian.
Global warming is Pascal’s wager all over again. however, if your primary concern is the truth, the wager is unimportant. Keep in mind, too, there is jeopardy on both sides.
If the imminent catastrophe hypothesis is true, then we have to basically dismantle modern industrialised economies. That’s a pretty big price to pay for a hypothesis. For this reason it deserves more scrutiny than most other scientific claims. Yet people are saying “shut up! don’t question it! the science is in!”
There’s negative consequences if we do nothing, there’s negative consequences if we do too much. We need to find a happy medium.
I was going to link to this article as a counter to the post I linked to the other day. The headline is “Stronger Link Found between Hurricanes and Global Warming: A century’s worth of records suggests that hurricanes are on the rise and a warming Atlantic is to blame.” Most of the article is making side swipes at “critics” (of global warming? of athropogenic global warming? of climate models? of the hypothesis that the number of hurricanes are increasing? of what?).
“Critics of such a link argue that this trend is merely because of better observations since the dawn of the satellite era in the 1970s. But the authors of the new study say the conclusion is hard to dodge.” What “link” are these critics arguing against? Does anyone doubt ocean temperatures determine the number and severity of storms? The article doesn’t address how patches of ocean are getting hotter or why they would be getting that way almost 3/4 of a century before people ratcheted up the CO2 emissions. What “link” is in dispute?
I expect more out of Sciam. They’re doing the opposite of what good science reporting should do; they’re muddying the waters.
Like I mentioned before, I’m confused by economists being confused about carbon offset markets. Now Arnold Kling comes out against them:
But it’s not a free market. It’s an artificial market, created by the “carbon offset” nonsense… But selling it as a way to lower your personal or corporate carbon footprint gives me the creeps. When it comes to climate change, I don’t necessarily want to be called either a believer or a skeptic. But you can definitely call me a Lutheran.
Can someone please explain to me what the carbon offsetting upstarts are like the old Catholic absolutions? People are buying away their guilt. Why can’t there be a market for this? How is it different from the ‘organic’ movement (I’m working on the well-informed assumption that there’s no difference between organic and non-organic milk, for example)?
The number and severity of hurricanes
has hasn’t increased over the last 100 years:
The warming theorists — most of whom, no doubt, earnestly believe that human activity has triggered nature’s wrath — have the ears of the news media. But there is another plausible explanation, supported by decades of physical observation. The spate of recent destructive hurricanes may have little or nothing to do with greenhouse gases and climate change, and everything to do with the Atlantic Ocean’s currents.