The Science of Climate Change is Not Settled.

Via Nathan Smith
on May 25, 2010
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News Flash: Global Warming May or May Not be Something to Worry about.

A couple of weeks ago, published an article on two MIT climate scientists—Kerry Emanuel and Richard Lindzen—who disagree about whether or not we should be worried about global warming.

If you haven’t seen the article already, check it out. If you do nothing else, watch the video of Richard Lindzen. It would be, I believe, a brazen thing to dismiss what he says.

Even though you’ve probably heard–and likely believe, with good reason–that there a consensus that man-made global warming is here and that it is already causing shifts in the environment that may well be catastrophic...this is not the complete story.

It is true that an overwhelming majority of scientists who study the climate believe that human actions, if left unchecked, will result in potentially catastrophic changes to the earth in the next century. But there are those that disagree, and it is not possible simply to ignore them.

But what is the grounds for their disagreement and what does it mean for policy on climate change?

To put the point more finely, I’ll just quote Roger Pielke Jr., professor at CU-Boulder (as quoted in the Globe article):

If these two guys can’t agree on the basic conclusions of the social significance of [climate change science], how can we expect 6.5 billion people to?

The politics of climate change are at least as tricky as the science, so if there are underlying questions about the science, how can we possibly move on to answer the political issues?

A recent article in Wired magazine suggests that what the scientists need is a PR firm to manage their message. This position assumes that the science on climate change is settled and that scientists just need to market their position more vehemently and persuasively. Author Erin Biba interviews a CEO of a PR firm for the entertainment industry, Kelly Bush:

Bush says researchers need a campaign that inundates the public with the message of science: Assemble two groups of spokespeople, one made up of scientists and the other of celebrity ambassadors. Then deploy them to reach the public wherever they are, from online social networks to The Today Show. Researchers need to tell personal stories, tug at the heartstrings of people who don’t have PhDs. And the celebrities can go on Oprah to describe how climate change is affecting them—and by extension, Oprah’s legions of viewers.

“They need to make people answer the questions, What’s in it for me? How does it affect my daily life? What can I do that will make a difference? Answering these questions is what’s going to start a conversation,” Bush says. “The messaging up to this point has been ‘Here are our findings. Read it and believe.’ The deniers are convincing people that the science is propaganda.”

I think this is misguided. It’s important to talk about how climate science affects us, but not through brute persuasion. A PR campaign works if you can control the message. But climate science is not a closed question and different viewpoints are bound to emerge. So, a PR campaign on the part of climate science has a tremendous potential to backfire. People hate to be lied to, especially by those they are supposed to trust, like scientists. I think this is why the Climategate emails were so damaging, even though they had very little to do with the underlying theory of climate change. The fact that some climate scientists seemed petty and shrewd in their approach to the issue undermined their public credibility. If scientists launched a PR campaign on the assumption that the science is settled, it will likely have a similar effect.

Why? Because the science is not settled. Period.

It would be a mistake to think that what we need to do is, first, get the science settled and then, second, work out the politics. In fact, there is a natural back-and-forth relation between the science and the politics, or the theory and practice to use a different terminology. Moreover, the science of future climate projections is not something that can be settled in an ultimate sense, so to wait on a settled theory to inform our practice would be to wait an eternity and never to act.

This is why you get a debate like the one between Lindzen and Emanuel, where one person claims that the risks posed by climate change do not warrant the kind of action that would new taxes on business (and inevitably depress economic growth) and the other says that the risks absolutely do warrant just this sort of action.

What is this debate about exactly? And what does it tell us about the science of climate change?

Climate models

What is a global climate model? Basically, it’s a complex mathematical simulation of the actual earth. The model is based on a number of equations (biological, chemical, physical, etc.) that describe the relationships between various thermodynamic systems over time. So, when we “model” the climate in the future, what we are doing is simulating (or representing) what changes result from varying the inputs into these equations.

It might be immediately obvious that it is difficult to determine the equations governing thermodynamic relations in large biological, chemical, and physical systems. In fact, there are different equations for measuring these kinds of things, resulting in different models. Second, since the initial inputs measurements are supposed to be taken from all over the entire earth, there is some uncertainty in these measurements. Indeed, global measurements are quite difficult to pin down. These issues lead to variability in the outputs of the models. So, we have the difficulty of defining the appropriate inputs. But even if we use the same inputs (say, the same increase of CO2 emissions globally), we might get different projections based on different models, and each model will have a range of accuracy.

But this is pretty standard stuff for scientists to work out. We get in trouble sometimes when we translate what scientists do into ordinary language. For instance, we speak of predicting certain atmospheric conditions in the future. These models do not predict anything. They are not magic 8 balls or crystal globes. What these models do is they make generalizations about changes to systems based on changes to inputs. They describe what are called “counterfactuals.”  For instance, they tell us that if there were 400 ppm CO2 in the atmosphere, this is what would happen to global surface temperature. If global surface temperature were 3 degrees higher than today, this is what would happen to sea level, glaciers, ice caps, etc. These conditional statements are contrary to fact. That is, this is not how it is today, but we want to know, based on our best description of the mechanisms governing our global climate, what would happen if this were the case.

Models and Truth

Models are confirmed when new data that we collect shows that the counterfactuals that the models predicted would hold actually do hold. What we have found in recent years is that our models have, by and large, been underestimating the effects of changes to inputs in the system. This is why there is talk of additional mechanisms (like the reflectivity of ice sheets, or absorption of water, or reflection of water vapor) as needing to be factored in to our equations.

I don’t think any of this should surprise scientists. But what should surprise you is that the very nature of counterfactual generalizations is such that these statements cannot be known with %100 certainty. We invariably run into the old problem of induction. That is, no matter how much data we collect, no matter how good our mathematical equations are, there will always be a level of uncertainty when we make generalizations. So, the science cannot be settled.

Risk assessment and values

But this does not leave us without options. In fact, it suggests that our tactic should not be to beat people over the head with more science. Instead, what we should do is introduce a normative (or value-laden) element to our understanding of climate science. This shows that the issues associated with global climate change are unique. They are not like many other scientific problems. They require us to make judgments about how much risk, how much change, and what kinds of conditions we are willing to tolerate. There is an element of risk assessment and value that cannot be separated from the science.

In a certain sense, this is good news. Think of it this way: I’ll bet you have life insurance and property damage insurance even though you think it’s highly unlikely that you will die soon or that your property will be damaged or lost. In fact, I’ll bet that you have this insurance AND you also do everything you can not to die and not to allow your property to be damaged. What this says is that we value our lives and our property very highly. In fact, we value these things so highly that we are willing to pay for insurance against something that we think is extremely unlikely, something we actively oppose.

One way that climate change is different from these other issues is that climate change is not risk about what will happen to us, but risk about what will happen to future generations. So, the cost-benefit analysis is a bit more tricky, but it’s not that unusual. Just think about how we already talk about funding education (which, of course, if we are voting we can’t possibly be benefiting from). Or think about infrastructure or urban planning which is certainly something we might enjoy now, but is most likely planned for 20 to 30 years in the future. We need to see our global environment in a similar light.

What we need is an appropriate way of placing a value on the global climate. And, then, we need to assess how much we are willing to pay in order to protect what we value. In many ways, this is the genius of Greg Craven‘s argument for doing something about climate change (watch video below). This argument puts the risk assessment at the forefront and leaves the complicated science to the side. This is the right approach.

In a certain sense, this is why I think the idea of “sustainability” is the right way to think about climate change. Rather than trying to figure out how different policy changes will effect the complicated climate models, what we need to do is seek a different approach to consuming, dispensing, and distributing planetary resources that reflects our core values about the global environment now and in the future. If we value the future life of our planet highly, then we need to move to a place where continuing our lives here is mutually sustainable with the ongoing well-being of the global climate system.


About Nathan Smith

Nathan Smith is a philosophy professor at Houston Community College - Northwest. He's a father of two and husband to fellow elephant columnist, Joana Smith. As a philosopher, he specializes in Descartes, the philosophy of mind, and phenomenology. He's interested in all kinds of things, but he blogs primarily about politics, spirituality, and good, green living. Follow him on twitter @smithnd. And share your thoughts in the comments; he doesn't bite.


7 Responses to “The Science of Climate Change is Not Settled.”

  1. Greg says:

    What is scary or sad, depending on your view, is that the science does not really matter. The factor driving the Cap and Trade legislation is greed, pure and simple. The scam in which Barack Obama has participated from its inception, and that Al Gore is deeply involved with, along with Goldman Sachs and a host of the usual suspects, will net them billions in profits for producing no product at all but for simply taxing those who do produce. The scheme drives all the PR and has driven the climate gate science scam. A good journalist following the Chicago Climate Exchange and Shore Bank will find corruption at a staggering level. Heads up green movement.

  2. Andrew says:

    dear oh dear … .. if you want your climate science from someone who takes $2,500 a day from coal and oil—go for it. Lindzen is perhaps the most "respectable" of the sceptics. But sadly, that not's saying a whole lot.

    Though I agree with the above that cap and trade is probably not going to do much good apart from breed more corruption and money for those willing to go that way. A carbon tax, straight down the line, would be a better start.

  3. smithnd says:

    Greg and Andrew –

    I don't get this opposition to "cap and trade." This is essentially the same system that currently exists for sulfur dioxide emissions. Yes it's a market. Yes people will make money off it. Does that matter?

    Andrew, I find the "$2,500 a day from coal and oil" claim difficult to track and a bit misleading. From the link you post (which goes to another link) it appears that the sum was paid for a per-day consulting fee. This doesn't sound outrageous. Impugning Lindzen for this is a bit like the people who say that Paul Krugman worked for the board of Enron. It's just a lame attempt to draw a line between one person and a disreputed organization.

    Look, there is no doubt that Lindzen's position is about as plausible as the position of those who deny the theory of evolution. But that doesn't mean that there aren't good scientific reasons for these positions. What I try to point out here is that for you (or anyone else) to say that "the science is settled" or "there is a consensus" about the causes and future effects of global warming is based on a misunderstanding how science works.


  4. Andrew says:

    thanks for your reply ….

    you wrote …

    "Look, there is no doubt that Lindzen's position is about as plausible as the position of those who deny the theory of evolution. But that doesn't mean that there aren't good scientific reasons for these positions."

    I really wouldn't worry about this normally. But I'm afraid it looks like you're joining in an old-fashioned "create doubt" exercise. Is that what you mean to do? I'm pretty sure it's not. I'm just confused about it because, in the statements above, … are the deniers implausible or are there good scientific reasons? Do you mean both? I don't quite get what you're saying. If there are good scientific reasons, what are they? Have they been published in scientific journals? If Lindzen is implausible and doesn't have good scientific reasons, who does? And if it's not Lindzen, why are you promoting him? I guess in the end what really concerns me is why you're promoting Lindzen so clearly if you think he's so implausible.

    "What I try to point out here is that for you (or anyone else) to say that 'the science is settled' or 'there is a consensus' about the causes and future effects of global warming is based on a misunderstanding how science works."

    Isn't this maybe conflating things? Or maybe I haven't understood what you're saying … sure, if you understand science it's never perhaps 100% settled (even perhaps about gravity etc etc). However, that doesn't mean there's never a consensus. You're conflating the two—my understanding is that consensus matters in science precisely because nothing is ever absolutely settled. There is, however, most definitely a consensus on climate change. A consensus doesn't mean absolutely everyone agrees. It means that just about everyone agrees, and that this has been tested via peer reviewed papers that discuss experiments, data and theories. The consensus on climate change is absolutely huge. The sceptics are notoriously weak on peer reviewed papers, and even worse on counter-theories, for all the effort they put into trying to undermine the fact of the consensus. And I'm afraid I've yet to see a single instance in which a sceptic, challenged with hard evidence, has backed down. It may have occurred but I've never seen it. That kind of removes them from the discussion, as they're not really discussing. And yes, if you're wondering, I have often seen scientists reply to, analyse, engage with, sceptics' points, not always with patience, but often with surprising patience.

    Or, to put this another way, are you arguing that the science is never settled on anything, or that it's particularly unsettled on climate change? Because if you're just saying that the science is never settled, therefore climate change science is never settled, then that's not really very interesting in the end. Especially since here it looks like you're saying that there's something especially unsettled about climate change.

    And taking money from coal and oil doesn't always mean you're going to state certain arguments, but on this issue there is indeed a long and sad history of it meaning exactly that. See James Hoggan's book, The Climate Change Cover-Up. Lindzen is also associated with quite a few organizations that do take coal and oil money. I almost agree that PR might not be the way to go. I certainly think your motivation is completely right here .. you're right, people don't like to be lied to .. The only thing is that they are being lied to by the sceptics in what is a huge and expensive PR exercise that has been going on for decades. And of course, climate change scientists won't have to lie in their PR. 🙂

    As for making money from the carbon market—sure, good luck to people, although I have to admit I don't have faith in the market in the end as a problem solver. The problem with the cap and trade markets are many however. They kind of avoid the larger problems of the social changes that might be needed — they kind of promise climate change action with as little real change as possible . They are open to corruption precisely because not only can you make money, but you can make it without any significant reductions in carbon emissions—if you're clever. One simple way to do this is to fudge the figures, which I believe has been known to happen in existing schemes. Perhaps this all boils down to the fact that they're open to corruption because they're just too complex. A straight carbon tax simplifies matters no end. And we'll probably agree at least that what matters in the end is whether carbon emissions are reduced or not.

    But I'll admit I don't know much about this last bit.

  5. smithnd says:

    Andrew –

    Appreciate your thoughts. I'll try to clarify the argument:

    First claim: We should not simply dismiss people like Lindzen because of the scientific "consensus" or the fact that the science is "settled." **And it's not just Lindzen. Look at what happened to Judith Curry (who seems to be a very reasonable and thoughtful person) when she spoke out against some of the things that are said about climate science.** I see the distinctions between these two terms as rhetorical. Each could be understood in terms of a Khunian "paradigm" or some such. In other words, you've got a relatively stable theoretical view of the issue, established by the work of many scientists who publish in peer-reviewed journals, etc. Climate modeling represents the current paradigm of climate science. Perhaps this will shift at some future date, i.e., our climate models might radically change, but likely not in ways that will result in the earth cooling or anything like that. However, there are gaps in this paradigm. There is a lot that is unknown about how the climate works, and when models try to talk about specifics (where and when droughts, monsoons, etc. will occur), it seems like there is some shaky ground here.

    Second claim: As a result of claim one, our approach should not be "let's PR the science better", "shout it from the rooftops", or smear anyone who disagrees. This is misguided because it relies on the view that the science is settled and that all we need to work on is messaging. (I then engage in a bit of a digression explaining what models actually do and do not do.)

    Third claim: Since this wrongheaded, yet predominant, tactic (espoused by the folks over at and, who do some really useful work, but tend to have this messianic/brute force methodology) is a dead end, let's try a new approach. I suggest that the way we should view this is in terms of risk-assessment, recognizing that our views about the climate are value-laden. That is, when we talk about possible future changes to the climate, these scenarios are good or bad for us. In this vein, I support the idea of "sustainablity" (and I might add perhaps the idea of social stability and human rights). These values can help us to chart a way forward even if we allow certain (local) uncertainties in the projections about future climate.

    As I understand it, climate modeling is a very fluid and tricky bit of science. There are an enormous number of potential causes that shape the climate: crazy stuff like the position of the sun relative to the orbital plane of the galaxy, down to the ability of eco-systems to absorb and/or fail to absorb greenhouse gases. What I have heard (I don't read peer-reviewed journals on climate, I'm not a climate scientists, I'm not even a scientist) is that there is a tendency to rely very heavily on a few tried and true models, or a family of models that are all similar in certain respects. If I were a climate scientist, I suspect that I would be publishing a lot of critical articles about the underlying "groupthink" that may or may not be going on here. Would I then be a climate denier? No. For all I know, we may be vastly underrepresenting the effects of climate change. Indeed, I think this is what has many scientists in panic mode right now.

    I'm going to have to reserve another post for the cap and trade thing. I see that this is a thorn in Greg's side. I've gotten into it with him before. I think cap and trade a great idea. I think cap and dividend or cap and pay of the debt are stupid ideas. But this is an entirely different issue that will require its own post.

  6. I savour, cause I discovered just what I was looking for. You’ve ended my 4 day lengthy hunt! God Bless you man. Have a great day. Bye