I want to formulate a basic case regarding global warming based on some study I've been doing in response to global warming denial. In addition to the basic case I want to address some common skeptical claims.
I think a good place to start if you are trying to formulate an opinion about this is to look at the strength of the scientific consensus. Some of this is complicated and most of us aren't experts. Relying on experts is rational as a starting point. What do they say?
The scientific consensus is pretty overwhelming. The Intergovernmental Panel on Climate Change (IPCC) was a massive effort to assess the scientific consensus. It concluded that global warming is real, the recent spike is the result of human emission of greenhouse gases, and that it represents a serious threat to human kind as well as other living species. No scientific body of international standing rejects these conclusions. Studies show that 98% of climate scientists accept the IPCC conclusions and in fact the greater the level of expertise (as measured by the number of papers published) the more likely the scientist was to accept the IPCC consensus.
So why believe that global temperatures are rising? Because multiple peer reviewed studies show that it is. Take a look at this chart of global temperatures based on multiple studies.
You might ask, what are these based on? How can one know what the temperature was 2,000 years ago? The answer is that there are various proxies that can be used to attempt to answer that question including tree rings, coral, ice cores, and glacial records. These are imperfect of course. And the error bars generally enlarge the further away you get from the present day. But these various studies based on various proxies tend to converge on a similar conclusion.
The first historical temperature reconstruction produced a graph like this and it was referred to as the hockey stick. It was used by the 2001 IPCC Report, and, though the creators of it made obvious reference to the uncertainty associated with it, the IPCC literature presented it in a graphic without error bars. Global warming skeptics were outraged and aggressively attacked the scientists that produced the graph, even though the scientists presented the results tentatively and with generous error bars. It rose to the level of Congressional hearings. Wikipedia has a summary here. The whole Wiki entry is worth reading, but in summary the skeptics have made several runs at discrediting the chart. The first ended in disgrace (Saul and Baliunus). Next was an effort by a guy named Stephen McIntyre, which apparently did provide some decent correctives, but didn't change the overall conclusions. More recently a Koch funded study has tried again and failed (as I mentioned here). At least to this point. Meanwhile over a dozen peer reviewed scientific studies have been published confirming the general accuracy of the original study.
So what about CO2 concentrations in the atmosphere? Here is a historical chart.
Makes sense. You take massive amounts of hydrocarbons out of the ground and release the CO2 to the atmosphere and you get an increase in the concentration of CO2 in the atmosphere.
But why believe this is the cause of warming? There are a number of good reasons.
Here's one reason explained in some detail, but I'll offer the quick version. CO2 levels have increased dramatically relative to the past several hundred thousand years and CO2 absorbs infrared radiation. There's no debate on that. But here's the key. Outgoing IR radiation can be directly measured. The amount of outgoing IR radiation has dropped at precisely the frequency at which CO2 absorbs IR radiation. That means this radiation is being absorbed rather than released to outer space. Effectively it is like putting on a blanket.
Another reason is that the stratosphere is cooling while the troposphere is warming. That is, the very top part of our atmosphere has been cooling while the atmosphere closest to the ground is warming. View the surface and upper air temperature historical plot here. That's pretty bizarre, right? What can account for that?
It was a long ago predicted consequence of warming due to man made CO2 emissions (see that prediction here). Go here for a good description of the causes. I don't think I can summarize it any better than it is done at that link.
These are not the only reasons. Several more are discussed here. Once again, in the scientific community the consensus is strong.
There are legitimate scientists that dissent. There are two main categories to the objections. The first is the claim that solar forcing explains the recent warming. The second is that the recent warming can be explained by what is known as the Cosmic Ray Flux (CRF) and its effect on cloud formation. A brief overview of these views and discussion of why they are by and large rejected in the scientific community is offered in this Youtube video.
So now, on to some of the questions that arise from the right wing disinformation effort.
Didn't scientists predict a global ice age back in the 70's?
The short answer is no. Time magazine had an article that made this claim but failed to provide a source. Surveys of the scientific literature revealed that at the time about two thirds of the experts expected global warming and a third expected global cooling (not an ice age). You'll notice based on the hockey stick graph that temperatures had been falling prior to the 70's. This was due to pollution from coal fire plants. There was debate about which effect would dominate. Would it be the cooling from the aerosols or the warming from the greenhouse gases? It's impressive that despite the history of cooling the majority of experts still expected warming and they were right. Since then there has been a lot more good research and the debate has been resolved. The warmers were right. For an overview watch this video.
Hasn't CO2 concentration changes lagged temperature rise in the past by 800 years? Doesn't this mean the rise in CO2 in the atmosphere is an effect of warming, not a cause?
Often CO2 rises have lagged the temperature increase, but not always. There are a number of different mechanisms that can drive a temperature increase, including the earth's orbital variation, volcanoes, solar irradiance, meteorites, possibly cosmic rays. In the present case we know it is greenhouse gases because scientists have managed to rule out alternative causes and because we are observing the predicted effects of temperature rise through artificial greenhouse gas emissions.
What causes the CO2 concentration changes to lag the temperature changes? Let me explain with an example using the earth's wobble as the dominant forcing mechanism.
The angle of the earth's axis to the sun varies from about 24° to 21°. When the angle is 21° there is less direct sunlight in the polar regions and ice forms there. Imagine what would happen as the tilt shifts towards 24°. More direct sunlight on the cap melts some ice at the cap. Melted ice converts to water. Water absorbs more heat than ice. Ice reflects radiation. So now with more water and less ice the earth as a system absorbs even more heat. That heat melts more ice and you create a positive feedback. Runaway warming and ice melting.
CO2 is trapped in ice. So as ice melts CO2 is released. This is why the CO2 concentrations lag the temperature change.
This process can reverse. As the earth's axis heads back to 21° we again get the freezing of the polar ice caps. Once again you go from a state where water is absorbing radiation to ice reflecting the radiation. This is a cooling positive feedback. The additional ice and snow can trap CO2 and methane from escaping to the atmosphere, once again creating a positive cooling feedback. The CO2 drop in the atmosphere once again lags the cooling.
The real concern is not the temperature effect of CO2. It's that the slight warming caused by CO2 can create a positive feedback due to the ice and other effects. At that point you can have runaway warming that can't be stopped even if you stop producing CO2 artificially.
What about the hacked emails? Don't these show a conspiracy within the scientific community to mislead the public?
Absolutely not. Multiple independent studies have confirmed there was no wrongdoing. For a fun video explanation of part of the issue, go here.
Isn't the sun the dominant climate forcing mechanism?
Of course. Without the sun there would be no climate. And solar output does vary. Approximately every 11 years the sun's polarity flips, and this results in altered solar output. But the conclusion in the scientific community is that recent solar changes cannot account for the rise in temperature we've experienced. The sun's output has been quite stable, following it's 11 year cycle regularly. Yet temperatures are rising. Why? The consensus of the experts is the greenhouse gases.
In times past CO2 concentrations were much higher. Today they are much lower. Why wasn't it a problem then?
Because the concern is not strictly the CO2 concentrations but the combined effect of the various temperature forcing mechanisms. Take the Huronian Glaciation. About 2 billion years ago the entire globe was covered in ice. Remember what I said about the feedback mechanism. An ice covered globe reflects solar radiation. That means when the entire globe is covered in ice solar output could increase a lot and yet you still may not be able to extract yourself from the snowball earth condition. That solar heat is just not absorbed.
And the reality was the sun's output was in fact much lower then than it is today. Solar heat was about 75% of what it is today. How did the earth ever come out of the snowball condition?
The answer is CO2. Volcanoes continued to erupt. When they did they emitted CO2. And there was no vegetation to extract the CO2 from the atmosphere. It took a really long time, but finally the concentration was high enough (about 1000 times what it is today) that ice started to melt. Once again the positive feedback kicked in. The ice melted rapidly. After it was all melted the earth continued to warm. Even with the sun producing a mere 75% of the output it is making today the earth was still much warmer thanks to the greenhouse effect. Vegetation began extracting CO2 from the atmosphere and though solar output increased the temperature on earth began to drop.
But why do I hear so much criticism about global warming in the media and from the right wing think tanks? These are smart people. They must know something.
Of course they are smart people, and they may know what the scientific community knows. But what is there job? Informing you? Or serving their owners and customers. I work for a corporation. In my professional capacity who do I serve? The owners and customers. Is Rush Limbaugh any different? Is the American Enterprise Institute any different? Limbaugh works for a mega corporation. His customers (advertisers) are mega corporations as well. He's going to spin tails that serve their interest. AEI is going to funnel money from Exxon to climate science denial efforts. Why? It serves their profit agenda. AEI's job is to confuse you for the interest of profit. They do it for economic matters. Why wouldn't they do it for environmental matters? You should expect spin and lies from them. That's what they deliver. Stop listening to them if you want to be informed.
This is all good and great for the Rush Lambaugh's and Michael Moore level audiences of the world. But the real intelligent debate is not here. The real debate is in ranking global warming as a threat, see here. And whether we should do ANYTHING at all about it, see here.
And btw, I should add, both views take nearly everything you wrote above as truth.
I'm glad you think this is not where the intelligent debate lies. I agree. But unintelligent debate is widespread. Let me note who it is that also occupies the Limbaugh realms. And I don't know what Michael Moore has to do with it. If he's making unintelligent debating points related to this give us some evidence. But here are some of the people that occupy that silly unscientific world. Maybe we shouldn't listen to them. There's Walter Williams with multiple, pathetic anti-science articles. Then there's Thomas Sowell. "There is no scientific consensus on the causes." In that article he tells us the CO2 lagged the temperature. It's volcanoes and clouds. Very little effect from humans. Back in the 70's scientists worried about an ice age. The EPA says man is the cause. Those are lies, according to Thomas Sowell.
The Cato Institute has a resident environmental expert. He goes to Congress as if he's an expert witness and has to get shut down by real scientists as he tries to pretend man is not causal. Watch the Congressional testimony here. Pure obfuscation, possibly lies. Watch the very highly respected Dr Richard Alley dealing with a hostile Republican Congressman and his standard science denial questions, many of which I address here. We don't know the causes, AEI tells us.
OK, you think AEI is a joke, I think they are a joke, Walter Williams is a joke, Thomas Sowell is a joke, Cato is a joke. Good, we have agreement. But given that these right wingers have significant influence as we can see in the halls of Congress (McIntyre's criticism of the hockey stick provided cover for Bush to ignore the Kyoto protocols if you check the link to the hockey stick controversy I provided) I think addressing their science denial nonsense is worth the time. You know these are morons. I know they are morons. But not everybody does.
But I'm curious on something. If you regard Sowell, Williams, AEI and Cato to be on the level of Limbaugh and Moore why do you listen to them? Why do you link to them on your blog? I see George Will. He's a big fan of the "70's Ice Age" argument. You seem to highly regard these people that are very unintelligent in terms of what they debate.
When you want data to carry your argument - you ignore the truth.
To coin a famous line in a movie - "Now I don't know what that all means, but it certainly looks bad." - Daniel Caffey (Few Good Men)
Copied commentary I agree with from AJ Strata.
This is not a surprise to me, since the ‘math’ behind the alarmists’ BS has been poor and amateurish (no error budget, no real math or scientific conclusions). Moreover, the lack of predicted warming has been a major clue the alarmists screwed up. Also, the need to go to exaggerated and unscientific claims was a clue the alarmists theories were failing to be reflected in reality. Recently all the cries of doom were from models pretending to be reality, why the measurements where heading in a different direction.
The irony here is the alarmists demanded more sensors on orbit to prove their point. But what those satellite clearly found was the alarmists were dead wrong. There is no escaping the results here. The data proves the models wrong. The atmosphere has been emitting the energy and not trapping it as predicted. No surprise, since a minor gas like CO2 cannot overcome the effects of the major elements of the atmosphere, which in turn cannot overcome the major influences of the oceans, which in turn cannot overcome the energy emitted by the Sun. We are talking many orders of magnitude in each jump from a marginal gas, to atmosphere itself, to massive oceans, to a nuclear furnace thousands of times larger than our planet.
Common sense and a scientific background would have made this obvious. The rantings of a has-been VP are no match for the forces of nature.
If I were in the US House of Representative I would do two things. I would suspend the EPA from any CO2 regulations and delegate NASA to do the science EPA is incapable of doing. And for the alarmists?
Go home and try next time to get it right. BTW, this is probably also enough hard data to shutdown the IPCC as well.
Thank you for this. Interesting reading.
Just as a starting point Chad, these objections of yours are what HP regards as arguments on the lunatic fringe. That's fine, but just know that this is real extremism.
Your first link is to supposedly 31K scientists that dissent from the scientific consensus. What qualifies someone as a scientist? If you have a science related degree. So dentists, engineers, and computer programmers make the cut. I can go up and down the halls of the company I work for and find engineers that are very good at what they do and don't have the first clue about climate science. They listen to Rush, so they think global warming is a liberal hoax. They'll sign this document. Does this prove something?
There is a difference between a layman and an expert. All opinions are not created equal. Expertise matters. Don't you think? We know the opinion of the majority of experts.
Your next two links are about evidence from Rush Limbaugh's official climate scientist Roy Spencer. True enough, he is a real scientist, so it's good to see you appeal to a credible source, but what does he say? Clouds are the issue. Like I said in my post there is an extreme minority of real scientists that think clouds are the issue. This is rejected by the vast bulk of the scientific community. We've spent billions of dollars and 30 years evaluating these alternative explanations. Their original proponents still cling to them even as the test data contradicts them, but that's human nature. People struggle to give up a pet theory that they have been committed to their entire lives. Einstein did the same.
This paper that you're referring to was published in a good journal, but the journal is not about climate science. And so it wasn't properly vetted. The journal's editor has since resigned because he says the paper should not have been published. It's been heavily criticized by the rest of the scientific community. This is a consistent pattern with Spencer. Serious and egregious errors force him to backtrack from his claims.
If you want to focus on that 2% of scientists that dissent from the consensus view you can. Go to Henrik Svensmark, Nir Shaviv, Henrik Fries-Christensen, Richard Lindzen, John Christy, Roy Spencer, or (until recently) Richard Mueller (though he's actually a physicist). These are real scientists and they reject the claim that man made CO2 is responsible in the way generally believed by experts. So far in my debating experience it's these same people recycled over and over. Meanwhile we have innumerable experts that say these few people are wrong. What's the rational conclusion?
But I'm curious on something. If you regard Sowell, Williams, AEI and Cato to be on the level of Limbaugh and Moore why do you listen to them? Why do you link to them on your blog?
Do I really have to answer this? Do you really not know what my position is on this???
Let me say it again: I trust economists on issues related to...wait for it...ECONOMICS. I trust environmentalists on issues related to...wait for it...the ENVIRONMENT!
In other words, I EXPECT economists to make stupid environmental arguments. JUST AS I expect environmentalists to make stupid economic arguments.
Let me ask you this: just because Chomsky is a "world renowned linguist" (which he is), does that make him, to YOU, also a "world renowned economist"? How about even a "mediocre" economist? It doesn't to me.
I can BOTH think Chomsky's economics are shitty and elementary AND look to him for issues regarding linguistics. If were debating linguistic issues, Chomsky IS the Paul Krugman, the Milton Friedman, the heavy weight that MUST be dealt with. Not so with issues not related to his specialty.
I've said this before on previous discussions with us and I'll say it again: much of the right is wacko on environmental issues. JUST AS much of the left is wacko on economic issues. No real surprise there.
Environmental issues ARE economic issues. Economic analysis is applied across disciplines. Education, health, crime, and yes, science. Your favorite economists are really bad at applying economics to global warming because they are badly misinformed about the scientific facts.
And here's what's interesting about that. Their errors always lean in the same direction. Service to wealth. Given that they are so bad when it comes to applying their discipline to science, what does that say about their ability to apply economics in other domains? What about vouchers? What about consumer protection? What about the welfare state? It's interesting that these same people always come down on the side of the debate that happens to align with the goals of concentrated wealth. Do you think that's an accident? I presume you can see that in the case of global warming. Consider that it might be happening in other disciplines they evaluate.
Fine. If you go that route, then Chomsky is even worse than I had initially presumed. He can't even apply economics to economic issues. :-)
But of course, I disagree. Just because you are an economists, doesn't mean you have to know environmental science, and vice versa. No matter how much you want it to be so.
And I've already addressed your "happens to align with the goals of concentrated wealth"...from your vantage point, as an economic novice, EVERYTHING seems that way. Shooot, probably capitalism itself seems that way. You can believe that all you want, but like the person who doesn't believe in basic global warming, don't expect people to take you seriously on those points.
Here's the difference between you and me. I provide links to your heroes making frequent ignorant and erroneous claims. Not just making claims I disagree with. Not just failing to emphasize what I think should be emphasized. Actually making factually erroneous claims and basing their economic conclusions on those erroneous claims.
You just say Chomsky is similarly ignorant and erroneous. But you don't provide any sources. The best you get is you refer vaguely to the work of a guy (Bogdanor) that is obsessed with Chomsky and says he's wrong, but as I look into it there's basically nothing there.
You know how long it took me to find error after error from Sowell and Williams, two people you link to from your blog? About 5 minutes.
Yeah, they don't have to know much about environmental science. Or education. Or health care. Or crime. Or housing. Or tax policy. Or welfare. But this is their job. Applying their profession to these various fields. You think their analysis is worthwhile whenever they apply their profession to these various domains. Suddenly though you've singled out one domain where their erroneous analysis doesn't prove anything. Why? Because we are both in agreement that they don't have the first clue.
This is why you link to them. Because of the way they apply their field to these various domains. But if we accept your logic you wouldn't link to them. "Just because they know economics doesn't mean they know education, health care, crime, housing, tax policy." So delete them from your blog. That's all they talk about. When they get outside the economics domain they are lost. Fine. They are lost on education and health care. Why do you link to them?
Economics is not the profession that must know all other professions. I realize that you would like it to be so - but I don't think anybody reading our discussion buys it and frankly, I don't think YOU buy it. It's a partisan point. (this is why economists specialize - where one takes economics AND becomes an expert in ONE other thing - ie, education, environment, trade, etc - but nobody thinks a true economist must be a know it all)
Let me reiterate: you can have a really bad understanding of the environment and a really good understanding of economics. Same goes in the reverse. Or to give another example, you can have shitty economic views (think Chomsky) and decent national policy views. This is the reason I still stick around - I try (try!) not to judge your national policy views based on your shitty economic views. And since I still have a lot to learn on national policy, I come here for the leftist view.
Let me just say a couple of things before bowing out of this discussion. First, here is a fairly recent criticism of Chomsky on education. Second, I strongly encourage anybody more interested in this exchange to read the two links I posted in my first comment above. Especially the one from Jim Manzi. Notice that it is actually the RIGHT that BOTH takes the environmental consensus most seriously AND applies solid economics to it. No need to pit one against the other. The true intellectual debate is not in these low level arguments, it's in arguments like Jim Manzi's and Don Boudreaux's.
Come on, man. You're being really stubborn here. You're better than this. Just admit it. I'm not saying Sowell and Williams have to know everything or they should be expert in everything. But if they are going to tell us what our policies should be on environmental issues shouldn't they at least have the basic facts in order? Doesn't it bother you that they don't? Why are you bringing Chomsky into it? Isn't it to distract from these blatant errors?
First, here is a fairly recent criticism of Chomsky on education.
Once again, come on man. I know this post of yours. That's why I asked you to show us an error from Chomsky that was more than just you saying he failed to emphasize what should be emphasized or didn't address what you think should be addressed. I want a real error. There's nothing here man. What does it say when after you've had all this time you can't actually come up with an error, and Sowell and Williams' errors are easy to find?
You have to admit that Chomsky is looking really good next to Sowell and Williams at this point. Chomsky is error free and your heroes are packed with errors. Doesn't that bother you?
As if Chomsky had something to do with this discussion. I think you are trying to distract from the painful realities. Sowell and Williams are embarrassing themselves. You know it and I know it. Just admit it.
Sure, some people take the Manzi route or the Boudreaux route. It's whack a mole with the right wing even when these arguments conflict. There's no global warming. Of course there's global warming. Nobody denies that. But it's not caused by man. Of course it's caused by man. But we shouldn't do anything about it. I don't see Boudreaux criticizing Sowell and Williams for their ignorant pronouncements. Why's that? Because they're all pulling for the same team.
The arguments I've put here are important. Not disputed by Manzi and Boudreaux, but they are disputed by prominent right wing economists and think tanks, including the people you look to for advice on how to allocate our limited resources. They are discussed in the halls of Congress, so it's a big deal. Our policies are being shaped by these errors.
And by the way, Walter Williams sits in for Rush occasionally. They see eye to eye. You're kidding yourself if you think Williams and Sowell are much different from him.
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