To be fair, climate change does often come very close to the sort of dodgy media misinterpretations of science that lands here. The debate has been politicised and polarised so much that everybody charges into the camps of "I believe in climate change" or "I don't believe in climate change". The problem with this is that it is religion, not science - in no sense does belief have anything to do with science. The opposition has been allowed to cast the debate in their terms, and they have cast it firmly in the realm of plausible-sounding arguments from authority, rather than evidence-based science. And they're being allowed to get away with it.

Whose idea was it to go around polling scientists about what they believe? What possible relevance could that have? The belief of people who work in the field is not scientific evidence in any form. Why are we trying to decide important scientific questions based on surveys rather than research? Even this post does it - most of the links are to opinions rather than actual research.

Rhetoric aside, the answer is: scientific evidence is lagging a long way behind belief here. While the people who are working on it can tell you what they expect to find, what they can actually prove is a lot less conclusive; the research suggests climate change is likely, but that's about all, and there's a lot of assumptions involved. Politicising this argument means people are staying away from the science because it doesn't support their position strongly enough. But on this site, I expect better.

Pete:

(Page 168) Economic models are better than climate models.

Is pretty much NOT what Levitt is arguing.

What Levitt is doing on that page is drawing a set of valid parallels between the methodological limitations of climate modelling and the similarly limited field of economic modelling.

Where your making a faulty assumption here is in stating that you'd expect climate modelling to be more accurate because its based on modelling a physical process. In reality this is anything but the case because what you're dealing with is a large scale chaotic system in which accurate modelling - were it possible - would rely on solving numerous non-linear equations.

There simply isn't enough raw processing power on the planet to do the maths necessary to accurately model the global climate.

The upshot of this, as with macroeconomic modelling, is that while the model might look to be doing well during periods of relatively stable trends, they're absolutely useless when it comes to dealing with system 'shocks', such as a market crash or an as yet hypothetical phase transition in the global climate, i.e. the much talked about 'tipping point'.

Climate models are statistical models much like economic models, they're just based on statistical physics rather market data.

If you've not come across it, I'd recommend you check out Philip Ball's excellent 'Critical Mass: How One Thing Leads to Another', which is one of the best popular science books you're ever likely to come across.

As for Levitt, having read his chapter there are a number of point on which he can reasonably be criticised for not understanding the science, but rather too much of what's flying around at the moment misrepresents his arguments for me to feel comfortable about the reaction.

No Andrew - wrong, wrong, wrong, wrong, wrong!!!
Scientific evidence for anthropologic climate changes is NOT lagging behind belief. Climatologists believe in climate change because of the evidence, not vice versa. And climate change is not likely - it is actually happening. It is a verifiable fact. Certain, not likely.
The reason that polling scientists is a good idea is because it demonstrates that the so-called controvery is entirely a media and ignorant layperson driven issue. There is no controversy in the eyes of the people who know what they are talking about. They all agree that climate change is occuring because they have done the research and can see the evidence.
One thing you are right about though is that we shouldn't be trying to decide important scientific questions based on surveys rather than research. And on this issue the evidence and research is unambiguous, irrefutable and VERY conclusive. It is not scientists who are politicising the debate, it is the denialists and people who have a vested interest in the status quo. Unfortunately, the debate has become politicised, and short of a major, catastrophic event occuring, it will remain so into the foreseeable future. Scientists continue to frame their input in scientific terms, but you cannot argue against scare mongering and denialism with purely scientific and rational means. If you could, there would be no religion or superstitious belief in god. Scientists need polticial support and they need people who are skilled in the polticial process to put forward their case. Otherwise they will be marginalised by the next big media driven crisis.
The media and general population has a very short attention span. Climate change is falling off the radar because of more immediate concerns such as health care and the state of the economy. If we want it back on the agenda (the political agenda), then we have to argue in political terms. Websites like this are helpful, not harmful, but we also need more. How about you get out there and do your bit, rather than criticising people who are.

Unity

"In reality this is anything but the case because what you're dealing with is a large scale chaotic system"

I don't this is true over climate time periods

http://www.realclimate.org/index.php/archives/2005/11/chaos-and-climate/

Everyone studies climate as a complex non-linear system. Few however expect chaotic behaviour from it

or

http://mustelid.blogspot.com/2005/04/we-cant-predict-weather-week-in.html

Andrew,

If you want the definitive scientific review of the evidence the IPCC AR4 report is here

http://www.ipcc.ch/publications_and_data/publications_ipcc_fourth_assess...

I'm certainly not arguing there are not still areas of some uncertainty, but each report these get fewer.

There's not much doubt that greenhouses gases have risen due to human emissions and that a doubling of CO2 in the atmosphere will create a global temperature rise between 2 and 4.5 deg C.

There are however a huge number of 'talking points' that have no scientific following that tend to get used and many of these seem to have strayed into that chapter.

Just a quick note to say I'm in the process of reconfiguring the server, so apologies for any cut outs... if you type any long comments, copy the text before yout hit submit so you don't lose anything!

There's a tricky example right there...

There's not much doubt that greenhouses gases have risen [...] and that a doubling of CO2 in the atmosphere will create a global temperature rise between 2 and 4.5 deg C.

This is a statement that is supported firmly by actual research and covered in the IPCC report (at least I think so, I haven't checked whether those are the right numbers).

greenhouses gases have risen due to human emissions

This one, on the other hand, only has circumstantial evidence for it - because it's a ferociously hard thing to prove scientifically. It's the sort of statement that you would expect to easily disprove if it was false, but which there is no easy way to prove if it is true, and that's most of the basis for scientists thinking it is. Which is reasonable, but not actual evidence. The IPCC report assigns it a probability of "at least 0.9", which is built on a "probability that we haven't missed anything" argument.

This sort of casual blending of research-supported statements and things which aren't readily provable is exactly what I'm talking about. Letting this stuff get confused is how we end up with people treating the first statement as a matter of belief. If you stick to just the first statement then it's easily supported by real science, but as soon as you mix the second statement in with it, we get this horrible debate over opinion polls.

The worst part is that the second statement isn't even important. It doesn't matter who made the mess. We still have the same problems.

I am not sure what you are reading there Andrew, but the IPCC 2007 Report is unequivocal about the causes of CO2 etc in the atmosphere, as follows:

"The increases in atmospheric carbon dioxide (CO2) and
other greenhouse gases during the industrial era are caused by human activities. In fact, the observed increase in atmospheric CO2 concentrations does not reveal the full extent of human emissions in that it accounts for only 55% of the CO2 released by human activity since 1959...... The increase in atmospheric CO2 concentration is known to be caused by human activities because the character of CO2 in the atmosphere, in particular the ratio of its heavy to light carbon atoms, has changed in a way that can be attributed to addition of fossil fuel carbon. In addition, the ratio of oxygen to nitrogen in the atmosphere has declined as CO2 has increased; this is as expected because oxygen is depleted when fossil fuels are burned. A heavy form of carbon, the carbon-13 isotope, is less abundant in vegetation and in fossil fuels that were formed from past vegetation, and is more abundant in carbon in the oceans and in volcanic or geothermal emissions. The relative amount of the carbon-13 isotope in the atmosphere has been declining, showing that the added carbon comes from fossil fuels and vegetation."
from "Climate Change 2007: The Physical Science Basis", p512.

There is a lot more, including the supporting evidence, but I can't include it all here. Perhaps you might like to go back and actually read the whole report.

Oh boy. Did you even read that chapter you so glibly posted up there without the slightest concern about copyright?

The are reasons to find fault with the chapter, there seem to be some mistakes in some of the science and there are some statements that are cause for concern*, but not one** of your comments above is among them.

Your mistake is consistent across most of your examples: you have misinterpreted their comment as opposing your viewpoint when, in actual fact, it confirms it. Taken one by one, here are my answers to your points:

1. They do not claim that in the 1970s an ice age was predicted, simply that cooling had occurred, nor do they claim "consensus", rather they say some scientists somewhere had raised the issue. Their quotes come from newspapers and editorials and we all know how reliable THEIR interpretation of science can be. This seems to me to be a warning of the dangers of looking to the press for our science rather than to the evidence and has no impact on the question of whether global warming is actually occurring.

2. I've read that page over and over and I can't see where they say economics models > climate models. Different to? Yes. Useful? Yes. Better than? Nope.

3. If you are basing your belief of rhetoric passed down from other people rather than on evidence and if you are taking that rhetoric on faith then you run the risk of elevating your belief to a religion. For many people, that has happened with global warming. Again, this is irrelevant to the debate of whether it is real or not. By claiming Lovelock as a "high priest" of these people they are entirely agreeing with you that he is not representative of the scientific consensus.

4. I find their argument compelling as it fits in with my experience of human nature, however, I also know plenty of scientists prepared to stand against popular thought (I am one, after all). On balance, I find their assertion dubious and I'm chalking this one up to you.

5. Well, yes. You've gone into it in considerably more depth than them (in that you have explained why and they haven't) but you seem to agree that water vapour has a greater effect on global warming than CO2.

6. They do seem to have written this sentence poorly and it contains an error of understanding, but it isn't the one you claim. They quite clearly state "Instead, all the heavy-particulate pollution we generated in earlier decades seems to have cooled the atmosphere by dimming the sun." So they agree with you that it was particulates that caused the cooling. Their mistake seems to be in thinking that, rather than covering up warming caused by CO2, it meant warming wasn't happening. This is an unfortunate mistake as, taken out of context, is does seem to be a denialist stance.

7. Oh, hang on, there is no 7. You appear to have stopped less than half way through the chapter. That's a pity, because on P187 is a very dodgy paragraph on solar panels that badly needs deconstructing.

This chapter, like all of human endevour, is not perfect, but it raises some very important issues and ones we would be foolish to ignore. Solving the problem of climate change through limiting CO2 emissions alone simply will not work. It relies on humans the world over to be altruistic and we just aren't. End of.

As for them virtually ignoring the potential downsides of a sulphur dioxide shield, again, did you actually read the whole chapter?! They discuss at length the risk (which is essentially that something bad we can't predict might happen and that, if it works, with no punishment to fear we might pollute more) and how this is still the best solution we have. It is cheap, it is easy, it mimics a natural event, which means we understand the potential risks and benefits better than any other solution, and it can be turned off instantly and the effect reversed in a matter of months. This contrasts with CO2, where an immediate cessation of all CO2 emissions would take decades to take effect, where the costs are potentially astronomical, the solutions are less well understood and the possibility of inadvertently causing greater harm higher.

I understand the fear associated with this solution. The issues are complex and involve all sorts of political risks as well as scientific. The subject is interesting and worthy of debate but this sort of Superfreakonomics bashing derails useful discussions that need to be had and drags us all into pointless mudslinging. Mud that is being aimed at the wrong targets. The authors apparently understood some of this risk when they wrote their section on the treatment of Semmelweis by the medical establishment. They have been proven prescient.

I'll finish with this direct quote of the 3rd and 4th paragraphs. These so called "global warming denialists" started their chapter with this:

These days, of course, the threat is the opposite. The earth is no longer thought to be too cool but rather too warm. And black soot, rather than saving us, is seen as the chief villain. We have cast endless streams of carbon emissions skyward, the residue of all the fossil fuels we burn to heat and cool and feed and transport and entertain ourselves.

By so doing, we have apparently turned our tender planet into a greenhouse, fashioning in the sky a chemical scrim that traps too much of the sun's warmth and prevents it from escaping into space. The "global cooling" phase notwithstanding, the average global ground temperature over the past hundred years has risen 1.3 degrees Fahrenheit (.7 degrees Celsius), and this warming has accelerated of late.

*IMO the throwaway comment about there having been global cooling for the last few years and apparent errors to do with the heat generation of solar panels are two of them.

** OK, maybe one.

RE: Oh boy did you even read

Copyright - I've linked to the chapter not posted it

1) I've just reread that page and can't see how you can get that interpretation

2) "By comparison the risk models used by modern financial institutions seem quite reliable"

5) You haven't understood my explanation - water vapour isn't an alternative to CO2 it amplifies the effect of CO2

I'm not calling them denialists - I am saying there is a number of 'denialist' talking points that have crept into that chapter.

I purposely didn't spend too much time on the geo-engineering aspects - that seems to be have done so much better for instance here

http://www.realclimate.org/index.php/archives/2009/10/why-levitt-and-dub...

and the follow up here

http://www.realclimate.org/index.php/archives/2009/10/an-open-letter-to-...

Ok, now I understand. You read this blog entry a few days ago:

http://scienceblogs.com/stoat/2009/10/superfreakonomics_global_cooli.php

And have rewritten it in shorter form and included a different figure. It looks from here as though, not only have you not read past halfway, you haven't read the chapter at all. Instead you've read someone else's misinterpretation of it and parroted it along.

The irony is, you claim people haven't elevated global warming to a religion and yet here you are doing exactly the thing that makes you most likely to fall into that camp.

Forgive me if I skip over your entries in future, you have shown yourself an unworthy member of the bloggers on Martin's page and I hope he reads this and reconsiders your place here.

There is a lot more, including the supporting evidence

That insert cites zero sources, unlike the rest of the report which cites them every few lines. It's also wrong. I wonder how it even passed review - except that it's not part of the report, it's just an insert, so probably wasn't reviewed at all. The rest of the report is far clearer on the quality of evidence and the fact that multiple things are going on here. It also details all the assumptions and uncertainties involved.

Random samples:

---

· Observed increases in NOx and nitric oxide emissions,
compared with pre-industrial estimates, are very likely
directly linked to `acceleration' of the nitrogen cycle
driven by human activity, including increased fertilizer use,
intensification of agriculture and fossil fuel combustion.

p502

---

Greenhouse gas forcing has very likely caused most of the
observed global warming over the last 50 years.

...

It is likely that there has been a substantial anthropogenic
contribution to surface temperature increases in every
continent except Antarctica since the middle of the 20th
century.

p665

---

Perhaps you might like to go back and actually read the whole report.

It's a thousand pages, mostly irrelevant. No. I'll check up on people who try to quote it though. The section that you want to read is 9.7, which is two pages and details how the available circumstantial evidence can be assembled to give their high-probability conclusions about anthropogenic influences. The following table, starting on p729, details the various conclusions that they can draw from the available evidence, and how strong it is for each of them. You will note that it's full of "likely" rather than "irrefutable proof".

I'm afraid this is a religious debate on both sides: the evangelists vs the athiests. Each call the other rude names. Each seems more focused on scoring points than clearing up the science.

I know that climate change is happening. I know it's happened for the history of the earth. I don't know how much of the current change is man made.

I also find it interesting that many of the evangelists show graphs tracking changes in temperature against changes in CO2 levels but in other (non CC) contexts are quick to use the saying "Correlation is not causation".

Everyone studies climate as a complex non-linear system. Few however expect chaotic behaviour from it

I depends what you mean by chaotic behaviour.

Relatively rapid shifts between periods of stable equilibria are entirely characteristic of a chaotic system, and this is pretty much the observable pattern if you look at the global climate over in terms of glacial-interglacial time or geological time.

Its all a question of scale, hence its not unreasonable to suggest that climate models offer a reasonable approximation providing that you assume that we're currently in a stable climate phase - which is self-evident enough to be taken as read - and that that stable phase will continue for the foreseeable future, which is altogether much more difficult to predict.

That's where and why the tipping point hypothesis complicates the debate - because it explicit postulates a set of conditions that fall entirely outside the scope of existing climate models.

1. Because they don't at any point claim an ice age was predicted or that there was consensus amongst scientist that the world was cooling. Perhaps their point was not "beware the journos", perhaps it was "evidence changes and with it so do interpretations" or "scientist get it wrong sometimes" who knows and who cares, it isn't important. What is important is that the criticisms applied to them simply aren't true. They don't claim there is an ice age coming nor do they claim that a majority of scientists ever believed it was, it is a straw man.

2. By comparison, the models used by financial institutions DO seem quite reliable. I wouldn't use them to model the climate though, any more than I would use a climate model to model the money markets, and they wouldn't either. They also go on to point out that the financial models missed the credit crunch so they admit they aren't all that good after all. Its an opinion only and one they are entitled to hold. Again, its a very minor point and distracts from the bigger debate to be had.

5. No I didn't, and nor did they. CO2 causes the increase in water vapour which goes on to cause the majority of the actual warming. Its positive feedback, I get it. They chose not to explain that at all, they can't explain everything in detail in a book of this type, but that doesn't make what they wrote factually inaccurate, just shallow. Their point is unclear, and perhaps fits with the "CO2 is not the biggest villain" issue which they admit was an error of judgement and poorly explained. All the same, there is a message worth listening to here, which is that perhaps we can achieve more rapid cooling by looking at other gasses as well as CO2. Removing water vapour is almost certainly an unrealistic solution but if we don't look at every possibility, we'll miss the good ones.