Deconstructing Channel 4's Great Global Warming Swindle
Those of you watching Channel 4's slick documentary, The Great Global Warming Swindle, may be forgiven for second guessing the foundations upon which many of us rest our policy research. The big guns were wheeled out to cut into Global Warming theory, and to the layman it could have appeared to be a bloodbath. Even the Channel 4 announcer took a swing before the start: "Climate change; is it down to the car you drive, the airmiles you clock, the light you didn't turn off? Questionable."
The documentary had plenty of big names, and much name-dropping of institutions and awards. The content, however, was riddled with old half-truths and some straw man arguments thrown in for good measure. The main content is summarized below, and annotated with comment and links for better info. I would be happy to discuss any of my comments here - feel free to make corrections, improvements, additions below.
1. Climate is always changing, this temperature is not strange. We shouldn't worry, as warming will bring "vineyards ... [a] wonderfully rich time." (Philip Scott) Climatologists have never denied that temperature variation has been a part of the Earth's history. What is worrying, however, is that the levels of CO2 are higher than they have been for 650,000 years (link) and likely in 20 million years (link), and the rate that current changes are taking place (see here and here) are much faster than they have been in the past. And while we may have vineyards and a wonderful time here in the UK, the developing countries will certainly get the short end of the stick.
2. Historically, CO2 trends appears to lag global mean temperature increases; CO2 doesn't drive temperature change. Yet another old argument. Oddly, they laugh at Al Gore's comment that the relationship between CO2 and temperature change is "complicated", suggesting he was glossing over the details and hid the truth. (If the carbon cycle isn't complicated, I don't know what is!) They then proceed to give an overly simplistic view of the climate, stating that during the heaviest industrialisation post-WWI, there was global cooling - therefore CO2 had no effect. They fatally neglect the time lag for warming from CO2, or the cooling impact from aerosols like SO2. But Real Climate to debunk their claim here: the apparent lag of CO2 from temperature in the historical records is a result of feedbacks which release more CO2.
3. Human's can't change the atmosphere - it's so immense. [Update 15.03.07: Having read the transcript, I see that misheard Stott's comment. He indicated the Sun was so immense, suggesting we were just small fry with no impact. I think my comment still holds, however.] Logical fallacy here - appealing to emotion and wonder. For a really accessible example of humans impacting the climate, we just have to look at the impact that the lack of airplane contrails had on temperature in the US after 9/11 (link).
4. Humans contribute only a minor part of total CO2. This is also not disputed. However, we do know that CO2 is a greenhouse gas, and that humans have contributed to recent increases in CO2 concentrations (link, link). It appears, that by disrupting the natural balance of the carbon cycle (which involves the atmosphere, plants, animals, oceans, and geology), we are able to warm the planet.
5. The surface of the Earth is warming faster than the troposphere, which is the opposite of what greenhouse warming theory would suggest. This argument has been going on for years. However, a 2004 article in Nature (link, and more discussion here) puts rest to these concerns, and the IPCC Fourth Assessment report will conclude that the troposphere is warming at least as quickly as the surface - consistent with theory. The confusion of whether the troposphere was warming quickly enough arose from a cooling bias from the stratosphere (which cooled as a result of less ozone). [Update 15.03.07: See also a US CCSP report which Christy himself co-authored here. It said: "Previously reported discrepancies between the amount of warming near the surface and higher in the atmosphere have been used to challenge the reliability of climate models and the reality of human induced global warming. ... This significant discrepancy no longer exists because errors in the satellite and radiosonde data have been identified and corrected."]
7. Cosmic rays can explain warming, as they affect cloud cover - which has a cooling affect. The argument from Nigel Calder and Danish space science skeptics has featured on this blog before, and on BBC's Newsnight - where Calder was thoroughly demolished by an atmospheric physicist from Imperial College. Basically, the Danes have found that cosmic rays produced ionized particles, an published it in a peer reviewed paper here. The article made no mention of global warming or climate change, but the documentery makes numerous jumps of assumption to say that those ionized particles would produce more clouds and thus cool the Earth. However, those assumptions have not been peer-reviewed, and there exists no long-term trend for cosmic ray flux, while global mean temperature keeps rising. RealClimate has discussed his claim (here). More arguments for cosmic rays came from Nir Shaviv et al. These have also been questioned in peer-reviewed literature here and discussed in RealClimate.org here.
6. Media and scientific self-interest in reporting more and more dramatic results. The global warming community needs to perpetuate itself to keep the money flowing. This, however, is not an argument against the science, but a clever tactic by the documentary makers to get the audience thinking that it is all a big conspiracy. Yet they fail to mention that hysteria is not new to the media - see crime, pedophilia, and immigrants as other examples. As for self-interest in science, it is of course in anyone's interest to promote the importance of their work - for publicity or money. However, the documentary makers failed to show how this debunked the theory of global warming.
8. Environmentalists say industrialisation causes global warming, and thus want to stop industrialisation and the great improvments it has given our lives. A straw man argument if I've ever seen one. By associating CO2 emissions with industrialisation and economic growth, the documentary plays an emotional trick by making us think that the quality of life we have will be taken away from us if the environmentalists had their way. While CO2 emissions are indeed associated with industrialisation, it is not a relationship that cannot be undone. For example, Vestas in Denmark have generated immense wealth by producing wind power generators. China has recently decoupled economic growth from greenhouse gas emissions growth (link) [Update 15.03.07: Better info in this and this article. Thanks, Bruce, for the comment.].
9. "Developing countries are coming under intense pressure not to develop." They finally claimed that environmentalists are stopping developing countries from installing fossil fuel plants, forcing them instead to use expensive renewable source of energy instead. This was called "anti-human". Unfortunately, no evidence was presented on this point - no data on World Bank projects, or similar. They did, however, visit a hospital that had been fitted with a solar panel, which could power either the fridge or the lights - but not both. The inference was that if environmentalists hadn't stopped the building of a fossil fuel power stations, the hospital could use the fridge and lights at the same time. Yet did the documentary prove that the hospital was in proximity to be wired to the grid at lower cost than the panel? You bet they didn't! [Update 15.03.07: See a further discussion regarding rural renewables in a new post by Chiara from In the Green here.]
Excellent Stuff Nathan, and very timely! The so-called 'documentary' on Channel 4 felt a bit like a flashback to the good old times where wise old men would tell you what was right and wrong. Funnily, hardly anyone of these guys has done any hard, serious research into the matter for years. Instead they rely on their accumulated convictions and titles to present what are really opinions as hard scientific facts.
Posted by: Till Stenzel | March 09, 2007 at 01:56 PM
Well done Nathan, good summary. Of course, I've loads of comments, but where do you start with something as big as this? Biq questions like: Am I blind to the possibility that climate change isn't anthropogenic because I'm part of the new nazi environmentalist system? Could this undermine half the basis of my work? Where the hell are these Environmental Journalists, and where were they when we needed them?
I'll make just mention a couple of thoughts for now,
1. Did they really try to suggest that global warming was invented by a renegade Swede in the 70s? Was there really a conviction of global cooling before that? What about Arrhenious?
2. If a government in a developing country actually decided to undertake the 'electrification' of poor rural areas, and did so with the sole interest of providing the best value solution with the support of western experts and in the absence of environmental concerns, would they really come up with big centralised fossil fuel power stations? There may be too many vested interests on both sides for the optimal solution to emerge, but if they started from a blank slate then there's every chance that local biomass generators, PV and wind would be cheaper than a vast national grid in, especially with rising fuel prices. Let's hope they wouldn't do such a bad job as the PV system at the hospital though.
3. Couldn't believe that they suggested that indoor air pollution from cooking would be best solved by electricity. Even Shell are into the provision of efficient little biomass stoves to replace open fires (link).
4. Zoe Williams in today's Grauniad tells us that "Calder...billed as the "ex-editor of the New Scientist"...was the editor of a non-peer-reviewed journal that, under his relatively short tenure beginning 1962, was five years old." (link)
5. What was the motivation of the 'anti-human' ex-Greenpeace founder? I know everyone does some idealistic activist stuff when they're young (Jack Straw, Pater Hain), but what point was he trying to prove by swinging so radically to the opposite pole?
6. Notice how they could only find three of the interviewees that would admit to not accepting money from big oil, not all of them, and certainly not Fred Singer.
7. Fossil fuels are finite.
Posted by: Simon Bennett | March 09, 2007 at 02:35 PM
Konichiwa! This is impressive Nathan - a comprehensive summary and attack. Though obviously I didn't see the programme (did anybody tape it?), it does remind me of the usual carbon suspects as introduced and amusingly pummled by that PV hereo Jeremy Leggett in 'the carbon war' (2002). Personally, I'm glad they're out there, even if they are petro-funded, we need em' to help keep people on their toes and becoming self righteous etc. Oh, and in case you're worried about being an environmental nazi all of a sudden, remember you're still at Imperial college, and that the real blinkered hard-core green action takes places elsewhere...www.earthfirst.org, por ejemplo. Chau for now!
Posted by: James Haselip | March 09, 2007 at 03:04 PM
An interesting post – like all documentaries (and there have been plenty on the pro- side), the counter-arguments are always presented badly, and no right of reply is given. Thanks, Nathan.
A quick comment about the oil-money conspiracy. I think a long list of people saying "I’ve not taken oil money, either" would have been rather dull. Three was plenty. What is more, I find the whole scientist-in-my-pocket theory rather fallacious; are people (e.g. Simon Bennett) really suggesting that men whose livelihoods rest on their reputations would be prepared to risk ridicule by falsifying evidence for the sake of a funder’s dollar? And do those who support global warming theory not also fund research? If so, should we distrust research funded by Greenpeace or FOTE as well?
In fact, it is in the interests of oil companies to find out the truth about their product: if it is changing the climate they need to investigate carbon capture and invest in renewables; if it is not, they need reliable (not falsified) evidence to make their case. I simply don't accept that one can follow a money-trail and reasonably infer bias as a result.
Posted by: Tom Papworth | March 09, 2007 at 04:36 PM
Point 4 is just silly. They've completely ignored the existence of natural CO2 sinks (plants, the ocean, etc.) By way of analogy, if someone gives you a gift of £10 every week, but you earn £200 a week, then this 5% increase seems trivial, until you consider that £190 goes into bills and rent. That £10 suddenly doubles your weekly savings.
Point 6 is a favourite of Lindzen which is countered here: http://www.realclimate.org/index.php/archives/2006/04/lindzen-point-by-point/
"the publlc demand made by scientists who are most alarmed by global warming is precisely not that more money go into [climate] reasearch, but rather that money go into research to increase fuel efficiency to develop carbon-emission-free fuel sources." Furthermore, funding for research is driven by the need to clear up the uncertainty surrounding fundamental scientific questions, yet it is the anti-climate science camp that is always highlighting uncertainties where as the IPCC has been continually reducing the uncertainty regarding the link between manmade CO2 and global warming. If those denying anthropogenic global warming don't like the research funds going to climate research, their best strategy would be to claim AGW is a certainty and no longer needs to be investigated.
Posted by: Wag Dog | March 09, 2007 at 05:53 PM
And Point 5 is out of date now that discrepancies in the satellite data have been largely resolved: http://www.realclimate.org/index.php/archives/2005/08/et-tu-lt/
Claims about discrepancies between satellite, radiosonde and ground measurements are a red flag that the claimant is not serious about science and care more about sounding a talking point. The fact that the C4 programme is using out of date data simply because it suits their goal is proof enough that they are far from being objective, fair or unbiased.
Posted by: Wag Dog | March 09, 2007 at 06:13 PM
Cheers Tom, thanks for picking up on my laziness.
The origin of funding is all too often used to try to infer bias. I agree that this is at best misleading, and at worst counter-productive as those that have been given funding in good faith find that their research is met with scepticism and this could discourage them from seeking such funding in future. It is useful to know the source of funding but results should, of course, be evaluated on the merits of the research and not on the footnotes. It seems that where the funder is able to bias a publication, this is reflected in the scope of the study or might lead to the shelving of results that are unfavourable. Published studies should be evaluated on their content independently of funding. Of course, this is not applied to much of what is published in the media.
Some of the cynicism around big oil funding has arisen from cases of Exxon giving research money to "go and prove that climate change isn't happening" (will try and find a reference to put here).
I do not think that one can infer anything from the absence of confessions from the other contributors to the Swindle programme. I admit that I gave this impression, it was a cheap, quick shot. I rather think that the inclusion of these proclamations in the show was pretty irrelevant; whilst the issues surrounding the need to attract Government funds by incorporating climate change research are more interesting.
There is no reason to distrust any peer-reviewed research, and everyone has the opportunity to perform or seek an independent evaluation. What so often clouds the topic, is non-peer reviewed selfishly-funded work, or misunderstood conclusions that make great headlines. Or the provision of equal time to both sides of the argument, when the balance of opinion amongst scientists is so firmly on one side.
Posted by: Simon Bennett | March 09, 2007 at 06:15 PM
China has decoupled its emissions from economic growth? Do you really mean that? Or did you just think it sounded good?
And if you did, by the same criterion (emissions rise with growth, but slightly less quickly than before) presumably we've all managed the same feat.
Posted by: DS | March 09, 2007 at 07:14 PM
I thought the programme's claim about CO2 rises lagging temperature rises was powerful. The article you link to which you claim debunks it only says that there could be a feedback mechanism causing 5/6 of the warming. The link to the further reading is dead.
Occam's Razor clasped in my hand, I will believe the Channel 4 programme for now.
Posted by: Bishophill | March 09, 2007 at 08:19 PM
DS:China has decoupled its emissions from economic growth? Do you really mean that? Or did you just think it sounded good?
And if you did, by the same criterion (emissions rise with growth, but slightly less quickly than before) presumably we've all managed the same feat.
Of course we (the North) have - from shifting production and innovating. My point was that the documentary tried to link industrialisation (and being rich, and happy) with CO2 emissions, and that if the environmentalists had their way it would all be taken away from us. Because CO2 doesn't always and only correlate with being rich and happy (see my two examples), their point doesn't hold water.
Thanks for visiting the blog, we appreciate the comments!
Posted by: Nathan Rive | March 09, 2007 at 08:31 PM
I completely agree with all your points. However -- and please don't take this as any kind of hostility -- I think the piece is not very well written.
It makes perfect sense to me, and to others who are already in the "choir," but when I put myself in the position of a lay viewer who saw the TV program, was filled with doubt about global warming, but had no real background in the science behind it, your arguments don't seem very persuasive.
So I wonder who your target audience is. If you're preachin' to the choir, it's fine, but if you're reaching out to the masses in doubt ... I wish I could be more specific about *why* it impresses me as not persuasive, but I'll have to think about that.
Posted by: tamino | March 09, 2007 at 08:36 PM
Bishophill:I thought the programme's claim about CO2 rises lagging temperature rises was powerful ... Occam's Razor clasped in my hand, I will believe the Channel 4 programme for now.
So you would claim that the cosmic radiation explanation (which requires the assumption leap that ionisation can produce meaningful cloud condensation nuclei - as yet unproved, and unlikely for numerous reasons - and would only be reasonable if there actually was a trend of cosmic radition alongside global mean temperature change) is simpler than the greenhouse explanation (where we know CO2 is a greenhouse gas, and feedbacks that could generate the apparent lag in the carbon cycle are known to exist, and reasonable explanations are available)? I worry that you have quite a blunt razor in your hand, Bishop!
Posted by: Nathan Rive | March 09, 2007 at 08:39 PM
Just one argument to refute the entire man-made global warming hysteria: "Water accounts for about 90% of the Earth's greenhouse effect". But you cannot blame mankind for that, can you? Just check it out, for instance here: http://www.junkscience.com/Greenhouse/
Posted by: Wonder | March 09, 2007 at 08:44 PM
Thanks Wag Dog, some great additions there. The £10 analogy is a good one. I was making a similar analogy today using the example of kids on a balanced see-saw, and where one was given a glass of water. That glass may only be 2% of their weight, it but will surely disrupt the balance.
Posted by: Nathan Rive | March 09, 2007 at 08:46 PM
Wonder:Just one argument to refute the entire man-made global warming hysteria: "Water accounts for about 90% of the Earth's greenhouse effect". But you cannot blame mankind for that, can you?
Water is indeed a greenhouse gas, and a powerful one at that. Remember, however, that greenhouse warming theory is not saying that the only greenhouse gas in the atmosphere is man-made, but rather that we have contributed an extra amount, that is starting to disrupt the existing balance - and cause a warming. It may be a small amount, but it's certainly enough to make a big difference. See WagDog's analogy above.
Posted by: Nathan Rive | March 09, 2007 at 08:52 PM
Couldn't find trustworthy references for my Exxon comment. The claims that have been made, however, have been real opinion leaders regardless of the truth in them. They are all the more believable when our politician's are telling us stuff like thisthis.
It's good to be reminded to be sceptical. Real expertise is evidently needed to make a fair interpretation of the probabilities here. But it is really just a question of probabilities and whether they justify precautionary measures. I am so far persuaded that they do.
If we are in a natural warming cycle that is generating an increase of atmospheric CO2, and which is coincidental with industrialisation, then can the additional contrbutions from fossil fuel combustion in the last 200 years been identified as such?
Posted by: Simon Bennett | March 09, 2007 at 09:37 PM
I'll just have a go at your first two points:
1.
"Climatologists have never denied that temperature variation" - well actually they did. The infamous "hockey-stick" removed the Little Ice Age, LIA, and the Medieval Warm Period, MWP. The hockey-stick has been discredited and dropped by the IPCC and don't believe everything they tell you at RealClimate;). Try ClimateAudit.org for balance.
"What is worrying, however, is that the levels of CO2 are higher..." - Why stop at 20millions years? How about 50 or 100 millions years? The truth is that current levels of CO2 are very low on a geological scale.
2. "Historically, CO2 trends appears to lag global mean temperature increases..."
Did Gore say that CO2 rises lagged temperature rises by 800 years? Nope. As for RealClimates explanation it is plain silly - an "unknown" something causes warming for 800 years then this "unknown" something stops and "the other 4200 years of warming could in fact have been caused by CO2." (Note the "could" - even they don't believe it. Then another "unknown" something stops the warming and the CO2 declines.
As for post-WW2, "they fatally neglect the time lag for warming from CO2" - this is entirely new to science. You should right a paper!
I could go on but this blog entry is really all about playing politics and not about the science. And that is the point the programme was trying to make.
Posted by: Kit | March 09, 2007 at 09:53 PM
Nathan
Sorry, what has this got to do with the point I raised? I'm trying to understand the feedback mechanism that is claimed to be the reason that temperature rises precede CO2 rises. You have pointed me to what you call a debunking but which looks to me like a restatement of your position. Where's the science?
Posted by: Bishophill | March 09, 2007 at 10:24 PM
Kit is dead right I read the same laughable explination on realclimate, utter rubbish. The bottom line in that in the last hundred years CO2 levels have almost doubled and this has produced an average temp increase of 0.6C. Temperature increases from CO2 is a log scale which means if levels double again the temp increase has to be less than 0.6C. Somehow I dont think I will be worrying about CO2 levels!
Posted by: Herold | March 10, 2007 at 12:33 AM
"the rate that current changes are taking place (see here and here) are much faster than they have been in the past..."
hmmm. Let's see now; currently we have global thermometer coverage, and we have better than annual resolution for temperature changes. We know that temperatures rose ~0.5C from 1910 -1940, and 1970-2000.
We also know that the NAS panel has expressed considerable reservations about temperature reconstructions prior to 1600. But even forgetting that, we do not have annual resolution of temperatures for the past million years. In fact, how much resolution is there of temperatures for up to a million years ago ? Is the resolution annual ? Decadal ? Centenial ? Because we have already established from the 20th century that you need resolution to decadal or better if you are going to make claims like that.
And your one functioning link doesn't make that case at all.
per
Posted by: per | March 10, 2007 at 02:37 AM
Herold says:
Neither statement is true. Since pre-industrial times, CO2 concentration has increased about 35% -- not doubled. Over the last century, global temperature has increased about 0.85 deg.C, not 0.6. In fact, global temperature has increased nearly 0.6 deg.C in the last 30 years.
This is a good example of the level of "truth" you can expect from denialists. They're happy to make pronouncements about climate change, but can't be bothered to find out what the numbers really are.
Posted by: tamino | March 10, 2007 at 03:06 AM
Kit:"Climatologists have never denied that temperature variation" - well actually they did.
Is that why they don't exist in this graph?
Why stop at 20millions years? How about 50 or 100 millions years? The truth is that current levels of CO2 are very low on a geological scale.
Is it possible that our data for 50 million years ago is less solid that from 20 and 0.5 million years go? And aren't our more recent time periods more relevant for comparison? Would you compare crime rates in your neighborhood to those from 20 years ago, or 100 years ago?
Did Gore say that CO2 rises lagged temperature rises by 800 years? Nope.
Did The Great Global Warming Swindle mention sulphate aerosol forcing as a cause for the post-WWII cooling? Nope. Did they mention aerosol forcing at all in their documentary? Nope.
As for RealClimates explanation it is plain silly - an "unknown" something causes warming for 800 years then this "unknown" something stops and "the other 4200 years of warming could in fact have been caused by CO2."
What part of (a) non-CO2 impacts to the climate, and (b) CO2-dT feedbacks seem silly?
As for post-WW2, "they fatally neglect the time lag for warming from CO2" - this is entirely new to science. You should right a paper!
Come on, you knew what I was talking about here. CO2 has less forcing than sulphates in the short term, but it stays in the atmosphere for a long time. Plus, the ocean takes many decades to heat.
I could go on but this blog entry is really all about playing politics and not about the science. And that is the point the programme was trying to make.
So playing to people's emotions by showing them dirty hippies, or calls for nationalisation of Shell, or a hospital running on a solar panel (with no further info) was not playing politics? Please. See WagDog's post above for a good discussion on the fallacy that scientists are trying to scam us all for research money.
Posted by: Nathan Rive | March 10, 2007 at 08:53 AM
Nathan
Bishophill:
Sorry, what has this got to do with the point I raised? I'm trying to understand the feedback mechanism that is claimed to be the reason that temperature rises precede CO2 rises.
One possible feedback is from phytoplankton (see info here). Cutting and pasting from a comment at RealClimate: "a reasonable guess for the lag has to be based on the biological response of phytoplankton to changing environmental conditions. Offhand, it seems reasonable that as the Milankovitch (orbital) forcings initiate the onset of the glacial termination there may be some sort of decrease in the zonal sea surface temperature gradient which would in turn lead to less zonal winds. Less zonal winds would seem to reduce vertical mixing in the surface ocean and induce a subsequent stratification of surface waters. The surface waters may be additionally stratified by an increase in melt water remaining at the surface (reducing the salinity of surface water, consequently increasing water column stability). These combination of these factors do not bode well for carbon fixers such as phytoplankton who are dependent on intense vertical mixing as a source of upwelled nutrients. Less carbon fixation would result in more CO2 remaining in the atmosphere as the glacial termination proceeds, acting as a positive feedback to the initial forcing. Of course, this sort of large scale response would take a long time to occur, and may in fact not happen until well into the glacial termination." (link)
I also pointed out that choosing the cosmic mechanism via a Occam's Razor-type choice doesn't really apply, given that to assume that the mechanisms required for the cosmic option (beyond what Svensmark et al. have shown) are occuring is a bit of a stretch, and for several reasons, unlikely.
Posted by: Nathan Rive | March 10, 2007 at 09:22 AM
Kit: This page summarizes a paper in Climatic Change about the triggering of ice ages. This is relevant for non-CO2 changes to the climate, and the CO2 feedback associated with it.
Posted by: Nathan Rive | March 10, 2007 at 09:34 AM
Per: I've fixed the link now. You're absolutely right, a claim like "ever" should be accompanied with a time period. The sea ice melting was fastest since records began - 1979. According to the article, it is alarming because, "The changes are alarming scientists and environmentalists, because they far exceed the rate at which supercomputer models of climate change predict the Arctic ice will melt under the influence of global warming - which is rapid enough." So rates are exceeding theory.
The CO2 increases were fastest since 1950. Neither are geological timescales, and hardly worthy of an "ever" description. Mea culpa.
This, however, doesn't detract from the fact that the arctic could be ice-free by 2040 (link), or that we are experiencing very high CO2 concentrations (relative to the last 500k or even 20 million years). This is an geoengineering experiment of global proportions.
Signing off for now, have a great weekend folks!
Posted by: Nathan Rive | March 10, 2007 at 09:55 AM
Just one argument to refute the entire man-made global warming hysteria: "Water accounts for about 90% of the Earth's greenhouse effect". But you cannot blame mankind for that, can you?
This is another old argument where the anti-science coalition refuses to acknowledge that the climate scientists have already factored this into their predictions. The denialists consistently fail to understand that water vapor is a feedback and CO2 is a forcing. You may have noticed that early enough in the morning the grass has a coating of dew, and in the winter one has to scrape the frost off windscreens. That's because the water vapor responds to overnight drops in temerature by condensing into clouds/fog/rain and coating cool surfaces. The same cannot be said of carbon dioxide. Even in parts of Antarctica where the temperature can reach as low as the freezing point of CO2 (-78.5 deg C) the CO2 doesn't fall out of the sky as snow. Unlike water vapor, once CO2 is released into the atmosphere it has a one sided relationship with temperature - CO2 traps more heat, but cooling doesn't remove it.
The relationship between the triad of water vapor, temperature and CO2 may be better understood via an economic analogy. Think of a businessman starting with a small number of employees who bring in a small enough profit to allow him to expland his staff by a small percentage. The added employees of course bring in more profit and hence he can hire more staff. But this doesn't go on ad infinitum since the investment in staff reaches a point of diminishing returns. And just like air cannot carry more water vapor once saturation point has been reached, the businessman soon reaches a limit due to lack of skilled labour, space to expand into, tax constraints, etc. Calamities may hit the business, which naturally lead to layoffs. Once business conditions improve, profits are restored, and staff get rehired. There is a feedback between staffing levels and profitability. However, the businessman also has a rich aunt who passes away and leaves behind a trust fund that releases $100,000 every year for the businessman to invest into expanding his business. He hires even more staff who generate more profits and so on until a new saturation point is reached. Now the yearly profits that his employees generate probably dwarf the cash infusion from his aunt's trust fund, and yet who would deny that the recent sudden expansion of his business is due to that single event -- the death of his rich aunt?
Posted by: Wag Dog | March 10, 2007 at 10:03 AM
Good morning Nathan
The comment from which you quote says that it is a "reasonable guess" for a feedback mechanism. The author of the comment says it is not based on any scientific data. I must say I don't find this a very convincing level of proof considering the level of economic pain which we are told we will have to endure!
Another question: if we assume that CO2 is operating as an amplifier, then what stops the feedback mechanism? What stops the temperature rising exponentially? Clearly this is not what has happened in the past.
Posted by: bishophill | March 10, 2007 at 10:31 AM
Thanks for the post, Nathan. It was very helpful in answering questions I received. At first, it was kind of frustrating because the documentary covered so many skeptical claims all at once, but since you and the guys at RealClimate provided an answer to all of them, it made my job much easier.
Posted by: reasic | March 10, 2007 at 12:33 PM
Hi Nathan,
"Climatologists have never denied that temperature variation" - well actually they did.
As you are aware when people refer to the "hockey-stick" they are talking about Dr Michael Mann's IPCC TAR graph: http://www.john-daly.com/hockey/hockey2.gif
As you can see no LIA or MWP - I call that denial.
"Is it possible that our data for 50 million years ago is less solid ..."
Are you saying my statement "that current levels of CO2 are very low on a geological scale" is incorrect? If you are you are wrong. Your analogy to crime is baffling.
"Did Gore say that CO2 rises lagged temperature rises by 800 years? Nope." The glacial record indicates that temperature drives CO2 levels NOT the other way round. Gore is being economical with the truth by not stating this and leaving it to the audience to assume the reverse.
"Did they mention aerosol forcing at all in their documentary? Nope." So it is OK for Gore not explain the CO2 lag because a future TV programme will not mention aerosol forcing?
"What part of (a) non-CO2 impacts to the climate, and (b) CO2-dT feedbacks seem silly?" Actually (b) but that's what the whole AGW debate is about.
Finally, both films were political, "playing to people's emotions by showing them dirty hippies" is no worst than showing, melting icecaps, hurricanes and drowning polar bears.
None of the above are caused by AGW even the unwashed hippies;)
Posted by: Kit | March 10, 2007 at 12:38 PM
As you are aware when people refer to the "hockey-stick" they are talking about Dr Michael Mann's IPCC TAR graph: http://www.john-daly.com/hockey/hockey2.gif
As you can see no LIA or MWP - I call that denial.
What on earth are you talking about? Both the MWP (1000-1200) and the LIA (about 0.2 deg C cooler at 1600-1800) are both clearly visible. Note that these are averages over global scales and large time periods. Were you expecting the difference to be more dramatic? Based on what evidence?
The glacial record indicates that temperature drives CO2 levels NOT the other way round.
Not so. One small part of the glacial record shows that CO2 can rise some time after temperature rise. As for the rest of the lengthy record, how can one conclude there is absolutely no feedback relationship present?
So it is OK for Gore not explain the CO2 lag because a future TV programme will not mention aerosol forcing?
I suppose Al Gore could devote a whole series of lectures explaining correlation statistics, time series analysis, coupled variable models, etc. but to make his slide show of a more manageable length he simply says the relationship is complicated, and indeed it is. By the way, he did mention one mechanism by which rising temperatures can cause more CO2 to be released - increased forest fire frequency. But he failed to mention the many physics experiments that demonstrate that CO2 absorbs infra-red light. So, Al Gore seems to be on your side when he illustrates only one side of the feedback.
Finally, both films were political, "playing to people's emotions by showing them dirty hippies" is no worst than showing, melting icecaps, hurricanes and drowning polar bears.
It would be great if everyone were rational scientists, then all the newspapers need do is publish scientific journal articles in whole and completely void of all emotion, and there would be no need for editorialising. Meanwhile, back in the real world, for a message to appeal to a wide audience, it must contain an emotional element that they can identify with personally. You can do this either honestly so that it reflects the reality of our situation, or dishonestly so that one is really fitting the data to a narrow agenda. And that is what sets the two films apart.
Posted by: Wag Dog | March 10, 2007 at 03:18 PM
Tamino said:
"Neither statement is true. Since pre-industrial times, CO2 concentration has increased about 35% -- not doubled. Over the last century, global temperature has increased about 0.85 deg.C, not 0.6. In fact, global temperature has increased nearly 0.6 deg.C in the last 30 years."
To start with CO2 level vary between 300 and 600ppm depending on where you are in the world, in fact they vary about 100pm across a 24hr period. You say 35% I say its more but the point is its a very large amount.
The average global temperature is equally very difficult to define even the best figures have an accuracy of around 0.5C.
Your comment that the temperature has risen 0.6C in the last 30 years ignores the fact that it had fallen for the previous 30 years as well (The total for the last 100 years is still only about 0.6C). At leased half of that total temperature increase happened before 1950.
Let me put it another way - 'There has been a massive increase in CO2 over the last 100 years that has produced a barely significant increase in temperature.'
Before you start telling me 0.6C or 0.85C if you like, is a significant increase in global temperature, thats only true if its significantly above your measurement error.
Posted by: Herold | March 10, 2007 at 03:27 PM
Another question: if we assume that CO2 is operating as an amplifier, then what stops the feedback mechanism? What stops the temperature rising exponentially? Clearly this is not what has happened in the past.
Why do you assume feedback implies exponential? The heat absorbing properties of CO2 gas does not rise linearly with concentration but follows a logarithmic function. That is, there is a point of diminishing returns, however this point may not be amenable to industrialised society.
Posted by: Wag Dog | March 10, 2007 at 03:34 PM
even the best figures have an accuracy of around 0.5C.
I'd like to see your reference that states the global average temperature is not being measured to a greater accuracy than half a degree.
Before you start telling me 0.6C or 0.85C if you like, is a significant increase in global temperature, thats only true if its significantly above your measurement error.
It is also a global average increase. Recall the old joke: A statistician is someone who can have one foot in a raging fire and the other frozen in ice, but he says he feels fine. Parts of the Earth are experiencing temperature rises much higher than 0.6 deg C and they tend to be in the higher latitudes which is consistent with the climate models. Other parts are getting colder which of course brings the average down. The global average temperature is an indicator of climate change, and a sensitive one at that. That said, it is possible to have climate change with a constant global average temperature, but the converse is not true.
Furthermore, if you still think 1 degree is hardly noticeable, then I'd recommend you read this series of articles: "The Difference a Degree Makes". The biosphere is more sensitive than you think.
Posted by: Wag Dog | March 10, 2007 at 03:51 PM
Hi Wag Dog,
"What on earth are you talking about? Both the MWP (1000-1200) and the LIA (about 0.2 deg C cooler at 1600-1800) are both clearly visible."
You have good eyesight!
"Were you expecting the difference to be more dramatic? Based on what evidence?"
Yes, see Nathan's response to my previous post. Compare the two graphs.
"Not so. One small part of the glacial record shows that CO2 can rise some time after temperature rise."
Only "one small part"? Are you sure? I think you need to check your facts - you can even get them from RealClimate .
"You can do this either honestly so that it reflects the reality of our situation, or dishonestly so that one is really fitting the data to a narrow agenda. And that is what sets the two films apart."
Which film are you saying was honest? Only joking, I think I can guess your answer.
Posted by: Kit | March 10, 2007 at 04:06 PM
Herold,
Wrong. Those who don't want to take my word for it can visit the World Data Center for Greenhouse Gases to get the actual numbers.
No, the POINT is: you don't know what you're talking about.
Again, anybody can visit the Hadley Center for Climate Change to get the actual numbers. They'll find that the maximum uncertainty in their estimate of today's global average temperature is around 0.135 deg.C. That's the upper limit to the error -- the probable error is less than half that, and certainly far less than 0.5C. Again, you don't know what you're talking about.
The global cooling from about 1945 to 1975 amounts to around 0.1 deg.C. Much more than half the total warming in the last century has occurred since 1975. Once again, you simply don't know what you're talking about.
I wasn't always a global warming advocate; I'm not a climate scientist, and until a few years ago I wasn't very interested in the issue. Then I found out about a paper by a "colleague of a colleague" (at the time I was working with astrophysicists) which disputed global warming, based on numerical analysis. That's my field, so I decided to investigate the issue in detail.
Yes, that's right, I decided to investigate the issue in detail. Since I'm a mathematician, and my specialty is the statistical analysis of time series, I'm pretty well prepared to do that. I have studied in detail the data for global and hemispheric temperature, both from instrumental measurements and proxy reconstructions. I have studied in detail the long record of CO2 concentration, both from direct instrumental measurements and from ice core data. As a result, I've come to the conclusion that global warming is very real, is caused by human activity, and is very dangerous.
When you said (and I quote) "... in the last hundred years CO2 levels have almost doubled and this has produced an average temp increase of 0.6C," you proved beyond any doubt that you don't know what the data tell us, either about global average temperature, or about CO2 increase. You probably haven't even looked at the data, you've just taken some denialist's word for it -- yet in your astounding ignorance, you feel entitled to belittle the efforts of thousands of climate scientists, many of whom have devoted their entire lives to the study of earth's climate.
I strongly suggest you follow this sage advice: It's better to remain silent, and be thought a fool, than to open one's mouth and remove all doubt.
Posted by: tamino | March 10, 2007 at 05:44 PM
Kit and Herold: I agree with your point that the bloggers at Real Climate do have a an explanation for the lag that is unsatisfactory to the those casually following climate research. Even Gavin's recent responses in the "Swindled" post do a better job:
"Try and get your head around the idea that two different things can be happening at the same time. One, the ocean and terrestrial carbon cycle is affected by climate. Two, the amount of CO2 in the air affects the greenhouse properties of the atmosphere. Part I is obvious from the paleo-record, Part II is measured in lab experiments and in observations. Together they do a pretty good job at explaining how cold it gets during the ice ages - which are paced by Milankovitch forcings. Without the radiative effect of the GHG changes, the ice ages would not have been so icy."
The C4 programme and anti-IPCC team would have you believe that the glacial record is the only evidence out there linking CO2 to temperature and hence the lag determines the causality. They tend to focus entirely on where the gap is biggest, the 800 year lag that occurs at the termination of an ice age. But the record itself is several thousands of years long and this gap is not evident everywhere. The RealClimate folks however write their explanations with a wider context that includes experimental physics. They tend to forget that some readers of their blog are coming fresh off from a Tim Ball lecture, Michael Criton book reading, Patrick Michaels article, or Martin Durkin programme, and can only consider one talking point at a time, the glacial temperature record, and are in complete ignorance of the long history of physics experiments that have conclusively established the causal effect of increased CO2 gas absorbing more radiative energy. The bloggers at Real Climate interpret the glacial record in this wider context and that is why they see a feedback being present. They are aware of a wider body of evidence going beyond just the glacial record to arrive at their conclusion. The absence of proof is not a proof of absence, thus the lack of any CO2 rise preceding temperature rise is not a problem to them as much as it seems to be a problem to us. That said, the paleoclimate record does contain one event of note - the Paleocene-Eocene Thermal Maximum where the release of CO2 and methane sparked a runaway greenhouse effect.
It is the success of the anti-climate science lobby that they can so easily spread this tunnel vision mentality. As long as we focus exclusively on the one discrepancy without the fuller understanding of the physics involved, they can lead us where ever they want to. And that is why blogs such as this one still have an important role to play is making the science more accessible to the general public. To sum up, and clarifying my reading of the RC position on this topic, the glaciation record shows temperature can drive CO2, but this does not disprove that CO2 drives temperature. It doesn't prove it either, but it doesn't need to since there is already a large body of other evidence, both experimental and observational, that shows this. Incorporating all streams of evidence (paleoclimate, experiments, atmospheric observation) leads to the feedback interpretation.
Posted by: Wag Dog | March 10, 2007 at 05:58 PM
Wag Dog,
I am sure you are aware that Gavin did not refute John A's point but went off on a tangent as you have done. The glacial record shows that CO2 rise lags temperature rise - that is a simple statement of fact. The programme was simply adding a detail which Gore had neglected raise in his film. I am sure you would agree Gore was unintentionally misleading his audience.
You and Gavin seem to be under the impression that stating the above means the same as denying CO2 is a greenhouse gas and its effect on temperature. The programme clearly described CO2 as a greenhouse gas. Rising CO2 raises temperatures - another simple statement of fact. What is in dispute is the positive feedback which is required to produce the very high temperatures projected in the future and its primary role in climate change.
I think the jury is still out on that. We will have to agree to disagree on these points.
Regards, Kit
Posted by: Kit | March 10, 2007 at 06:56 PM
You and Gavin seem to be under the impression that stating the above means the same as denying CO2 is a greenhouse gas and its effect on temperature.
I believe Gavin knows that the lag is not a denial of CO2's greenhouse effects, however the impression one gets from John A's postings is that he (John A) thinks it does. This impression isn't that unwarranted given that John A (of Climate Audit) also thinks that entropy and heat are quantities that can be added.
Rising CO2 raises temperatures - another simple statement of fact.
Good. We agree then that over long timescales there is a feedback between CO2 and temperature.
What is in dispute is the positive feedback which is required to produce the very high temperatures projected in the future and its primary role in climate change.
Seems like you're moving the goal posts. Accepting that CO2 causes temperature to rise, but then claim that the climate is insensitive to CO2 is inconsistent with all the climate models behind the IPCC sensitivity calculations (2.0 to 4.5 dec C rise when CO2 is doubled). Your position is more in line with Prof. Lindzen's who does acknowledge anthropogenic global warming but argues for low sensitivity. Most anti-AGW commentators who cite the lag in the glaciation record as refutation of AGW won't even acknowledge that much. Unfortunately for Professor Lindzen, the mechanism that he proposes for moderating the warming effects of CO2 has so far only been observed to operate on a regional and not global scale. If what you say about low sensitivity is true, Martin Durkin and his band of experts need to find such an Iris-like mechanism that acts globally, or show how the IPCC sensitivity calculations are in error, instead of trying to distract us with sun spots and cosmic rays.
Posted by: Wag Dog | March 10, 2007 at 08:10 PM
Wag Dog,
"Good. We agree then that over long timescales there is a feedback between CO2 and temperature."
No we don't. Are you sure you meant to use the word "feedback"?
"If what you say about low sensitivity is true, Martin Durkin and his band of experts need to find such an Iris-like mechanism that acts globally, or show how the IPCC sensitivity calculations are in error, instead of trying to distract us with sun spots and cosmic rays."
No they don't. I would suggest AGW climatologists need to prove high sensitivity. It is their theory after all. As for distracting us with alternative theories - I thought that's what science is all about. Remember AGW started off as a distraction;)
Posted by: Kit | March 10, 2007 at 09:19 PM
I believe Gavin knows that the lag is not a denial of CO2's greenhouse effects, however the impression one gets from John A's postings is that he (John A) thinks it does. This impression isn't that unwarranted given that John A (of Climate Audit) also thinks that entropy and heat are quantities that can be added.
No, that would be Tim Lambert who thinks that heat can be transferred irreversably without loss to entropy and that cold can flow to hot.
Two basic thermodynamics issues that Lambert screwed up on.
Then there's the question of whatever "bulk heat" is supposed to be since Lambert made it up. He was the one who added heats together, not me.
So whatever poisoned teat your sucking from Lambert, I suggest you stop sucking. Lambert can't help himself.
Posted by: John A | March 10, 2007 at 10:50 PM
Tamino
"I have studied in detail the long record of CO2 concentration, both from direct instrumental measurements and from ice core data. As a result, I've come to the conclusion that global warming is very real, is caused by human activity, and is very dangerous."
it is a shame then that you cannot articulate your reasoning. As a mathematician, you will know that correlation is very different from causation; and you haven't addressed the issue that CO2 in the ice record rises after temperature.
Wag-Dog
"the lack of any CO2 rise preceding temperature rise is not a problem to them ..."
yes it is ! You can bet your bottom dollar that if CO2 preceded temperature rises, they would be trumpeting it to the skies. They have merely distracted you by telling you to look elsewhere when you see this problem !
You seem to be mesmerised by this idea of positive feedback loops, without being aware of the problems. With positive feedback loops, you can make a computer model have any behaviour you want; but that does not make it reliable. You have to be able to show that your model has predictive value; and that is sorely missing from the models. Predicting the past with a highly pre-tuned model simply is not a good test of the models.
per
Posted by: per | March 10, 2007 at 11:15 PM
Climatologists have never denied that temperature variation has been a part of the Earth's history.
Yes they have. It's called the Hockey Stick, and its a clear denial of natural climatic variation. Even last year, Mann was still repeating the claim from the Hockey Stick that the Medieval Warm Period and Little Ice Age were not global climatic phenomena.
How about that for climate change denial?
Historically, CO2 trends appears to lag global mean temperature increases; CO2 doesn't drive temperature change. Yet another old argument. Oddly, they laugh at Al Gore's comment that the relationship between CO2 and temperature change is "complicated", suggesting he was glossing over the details and hid the truth. (If the carbon cycle isn't complicated, I don't know what is!) They then proceed to give an overly simplistic view of the climate, stating that during the heaviest industrialisation post-WWI, there was global cooling - therefore CO2 had no effect. They fatally neglect the time lag for warming from CO2, or the cooling impact from aerosols like SO2. But Real Climate to debunk their claim here: the apparent lag of CO2 from temperature in the historical records is a result of feedbacks which release more CO2.
Actually they don't make such a stupid case. They make the point that CO2 has never been shown to drive climate change in the past. when its been much higher and much lower than today's value. Never. Ever.
So unless there's some special pleading going on, carbon dioxide rise is irrelevant to future climate change.
Other people would give Al Gore the benefit of the doubt on this but I'm not so sanguine - carbon dioxide rises and falls as a centuries delayed response to climatic variation and Gore should know the difference and the temporal relationship between cause and effect.
The temperature of the Earth appears to be directly related to the output of the Sun, as well as other direct and indirect cosmological factors, and there appears to be a tight relationship between the two that there isn't with greenhouse gases.
The rest of your straw man arguments are similarly risible.
Posted by: John A | March 10, 2007 at 11:27 PM
Per:
I'm not surprised at the naivete of skeptics who make such a big deal about the fact that during a deglaciation, temperature increase precedes CO2 rise. After all, you're not climate scientists, and can't be expected to know all the ins and outs of modern warming or ice age dynamics. Even climate scientists don't know the whole story.
What astounds me is that so many of you, who don't know a wet adiabat from a hole in the ground, somehow feel qualified to pass judgement on the state of modern climate science. I would never presume to do so, despite being an active research scientist and having studied the issue in detail for years (and actually analyzed the data).
Climate scientists have never claimed that CO2 increase is the root cause of, or the only factor in, deglaciation. Why does temperature increase precede CO2 increase during deglaciation? Because it has to. CO2 does not increase for no reason.
One of the things that can increase CO2 is temperature increase. Warming the oceans reduces the solubility of CO2, so the sea gives up some of its vast store of CO2 to the atmosphere. Recent research also indicates that a nontrivial amount of CO2 can be trapped in ice sheets, so when they melt during deglaciation, that CO2 can be returned to the atmosphere.
None of which in any way alters the fact that CO2 is a greenhouse gas and contributes to warming the planet, both during glacial cycles and right now. During a deglaciation the situation is not so simple as “CO2 increase causes warming” or “warming causes CO2 increase.” Both factors are both cause and effect. But you skeptics seem to want to believe in a single simple cause-and-effect (but never both) relationship that explains everything. Perhaps wrapping your minds around the real complexity of the phenomenon, is just too much work.
If you want to pretend to yourself that you have such superior "common sense" that your judgement is to be preferred over the clear concensus of the vast majority of the climate science community, fine. Don't expect me to believe your fantasy.
Posted by: tamino | March 11, 2007 at 03:38 AM
Though obviously I didn't see the programme (did anybody tape it?),
James,
The entire programme has been uploaded to Google, see:
http://video.google.co.uk/videoplay?docid=9005566792811497638
You can watch it there and also download the file and watch it through FLV player using: http://javimoya.com/blog/youtube_en.php
Best regards,
David
Posted by: David | March 11, 2007 at 10:14 AM
Thanks for posting this debunk; having first read about the apparent links between clouds and cosmic rays in a Royal Astronomical Society publication, I was slightly concerned by this programme. Keep up the good work!
Posted by: Andrew Harmsworth | March 11, 2007 at 10:29 AM
Climatologists have never denied that temperature variation has been a part of the Earth's history.
Yes they have. It's called the Hockey Stick, and its a clear denial of natural climatic variation. Even last year, Mann was still repeating the claim from the Hockey Stick that the Medieval Warm Period and Little Ice Age were not global climatic phenomena.
How about that for climate change denial?
Ok, fair enough - I don't know what Mann has been saying recently. Now, please show me now where the Medieval Warming period and Little Ice Age do not appear in the graph I linked to in my comment March 10, 2007 at 08:53 AM. Also tell me that a paleoclimatology 101 class at university will tell me that the climate has never ever varied over time.
Actually they don't make such a stupid case. They make the point that CO2 has never been shown to drive climate change in the past. when its been much higher and much lower than today's value. Never. Ever.
So unless there's some special pleading going on, carbon dioxide rise is irrelevant to future climate change.
Yes, they do. They, (among other things) make the suggestion that if CO2 was rising so quickly post-WWII, temperature should have risen then as well. But it didn't (it fell), therefore they infer that CO2 can't drive temperature. In doing so, they obscure the truth by neglecting sulphate aerosol effects, and timescales over which warming occurs.
Other people would give Al Gore the benefit of the doubt on this ... Gore should know the difference and the temporal relationship between cause and effect.
I can't speak for Al Gore on whether he knows this difference. But as we have seen through arguments elsewhere in this discussion and in the literature, it was certainly reasonable for him to highlight the concern of rising CO2 concentrations.
The temperature of the Earth appears to be directly related to the output of the Sun, as well as other direct and indirect cosmological factors, and there appears to be a tight relationship between the two that there isn't with greenhouse gases.
Are you falling back on the Calder and Svensmark, and Shaviv arguments? Please show me a graph of long-term cosmic ray flux that shows a correlating trend with global mean temperate change. Are you aware of the counter-arguments of both their work? See point 7 in my original post above.
The rest of your straw man arguments are similarly risible.
Please point them out, I'd be happy to discuss them.
Posted by: Nathan Rive | March 11, 2007 at 11:27 AM
Your rebuttal really doesn't amount to much. The main points of the documentary were that C02 lags behind temperature increases, and that sun spot activity accurately matches both rises and falls in temperature. You talked about cosmic rays but that was really an afterthought to the sunspot argument. You conveniently ignore those points, and those points are the crux of the argument, they're also what disproves the current global climate change theory. HOW CAN YOU POSSIBLY THINK YOU DEBUNKED THE SHOW WHEN YOU DID NOT ADDRESS ITS MAIN POINTS? IT SHOULD BE BLATANTLY OBVIOUS.
What do you have to say about that? I'm honestly interested to hear.
Posted by: Eric | March 11, 2007 at 11:38 AM
Just to remind you, the argument about cosmic rays and clouds != sun spots. Just because the cosmic ray argument might not be true does not disprove the correlation between sun spots and temperature!
Posted by: Eric | March 11, 2007 at 11:42 AM
Kit:"Is it possible that our data for 50 million years ago is less solid ..."
Are you saying my statement "that current levels of CO2 are very low on a geological scale" is incorrect? If you are you are wrong. Your analogy to crime is baffling.
Ok, should we think back to when the Earth was a molten ball of magma? As long as the surface temperature is less than 1800K, we shouldn't be complaining?
The analogy to crime is quite reasonable - we want to make comparisons within reasonable contexts (in this case, timescales). I agree that choosing a "reasonable" context is up for debate. However, if we are concerned about the impacts of climate change on current ecosystems and current populations, comparisons with the last 1-20 million years are more relevant to 50-100 million years (say, when the dinosaurs existed). The WBGU (here) even limit their concerns to the last 10 thousand years: "If present-day lifestyles and economic systems fail to change, the probability of global climate changes occurring at a scale and at a rate greater than any seen in the last 10,000 years (the recent Quaternary period) becomes immensely threatening."
Remember, our concern about climate change is not because of temperature change per se - but of the impacts those temperature changes will have to humans and ecosystems.
Posted by: Nathan Rive | March 11, 2007 at 11:45 AM
Eric:
Your rebuttal really doesn't amount to much. The main points of the documentary were that C02 lags behind temperature increases, and that sun spot activity accurately matches both rises and falls in temperature.
I think the CO2 lags dT issue has been covered enough in this discussion board, and at Stoat. It boils down to: (a) CO2 is a greenhouse gas, (b) but there are other forcings that cause climate change - solar, orbital, (c) CO2 acts as a feedback mechanism of the initial forcing triggers as the Earth warms (i.e. oceans release CO2), and enhances the warming effect. dT temperature falls are also triggered by non-CO2 forcing effects. Our concern now is that recent CO2 conc rises are not feedback effects, but are anthropogenic - and they will cause warming (and future feedbacks.)
Sunspots: I assume you are referring to their solar irradiance vs. temperature graph? The one whose solar irradiance data stops misteriously stops at 1980 (see graph link)? There is no denying that the sun warms the Earth. If the documentary had continued the irradiance graph beyond 1980, they would have seen that irradiance has stayed constant after 1980, whereas global mean temp has risen dramatically. Odd how they left that out. See the full graph from the Max Planck institute here, or the PMOD at Davos here against global mean temperature here. See further discussion of the sunspot issue here and here.
You talked about cosmic rays but that was really an afterthought to the sunspot argument.
Would you agree, then, that the cosmic rays theory is rather questionable, in light of arguments and evidence against it?
You conveniently ignore those points, and those points are the crux of the argument, they're also what disproves the current global climate change theory.
I think that statement is questionable, in light of the literature, and discussion we have seen surrounding the documentary.
Posted by: Nathan Rive | March 11, 2007 at 12:34 PM
[I was having problems posting that last comment - I think an issue with Typepad. Apologies to anyone who has issues with posting, hopefully it will resolve itself.]
Posted by: Nathan Rive | March 11, 2007 at 12:37 PM
I've compared Nasa's temperature record with the graph as it appeared on the programme.
Deliberate distortion in my view - Ive commented in more detail on Ben Goldacre's 'Bad Science' site:
I'd noticed that the graph in the programme doesn't accurately reflect the Nasa data.
The easiest way to check is to superimpose the two:
http://img103.imageshack.us/img103/6634/sdodgygraphgm3.jpg
basically what they've done is to greatly exaggerate pre-1940 warming to make the post industrial 'dip' look a lot bigger than it is.
I've commented in more detail on this on Ben Goldacre's 'Bad Science' forum:
tinyurl.com/2mo7cl
Posted by: Dean Morrison | March 11, 2007 at 02:33 PM
Great post -- I'm linking to it on my blog! So much more informative than watching the actual 'doc', I'm sure.
Posted by: vanessa | March 11, 2007 at 02:39 PM
tamino sneered:
"I'm not surprised at the naivete of skeptics ... After all, you're not climate scientists, and can't be expected to know all the ins and outs ...What astounds me is that so many of you, who don't know a wet adiabat from a hole in the ground, somehow feel qualified to pass judgement on the state of modern climate science. I would never presume to do so, despite being an active research scientist and having studied the issue in detail for years (and actually analyzed the data). Perhaps wrapping your minds around the real complexity of the phenomenon, is just too much work...If you want to pretend to yourself that you have such superior "common sense" that your judgement is to be preferred over the clear concensus of the vast majority of the climate science community, fine. Don't expect me to believe your fantasy."
As a matter of fact, you don't know what my profession is, and you have no idea if I am a scientist, of climatological or any other persuasion.
you wouldn't presume to pass judgement on the state of modern climate science, but you sure can recognise the "clear concensus" of modern climate science; why thank you for passing down your insight on tablets of stone !
And as for "Even climate scientists don't know the whole story." ? Surely, they know the whole story when it's a story you want to believe ?
per
Posted by: per | March 11, 2007 at 02:47 PM
Great discussion. More attention should be paid to the curious idiological alliance between the far left and the far right that was behind the Channel 4 trashing of science. My own take on global warming skepticism is that it represents another example of the refusal by the far right to comer to terms with reality. Program writer Martin Durkin, however, appears to be closely associated with the far left British Revolutionary Communist Party. Program "scientific" consultant, Martin Livermore an ex-business PR man who does not even seem hold a BS in a natural science, is the Director of The Scientific Alliance, an extrimist organization financially backed by right wing idiological and business interests. Why did Channel 4 involve itself in this curious exercise in idiological psudo-science?
Posted by: Charles Barton | March 11, 2007 at 06:31 PM
Charles Barton said:
"Great discussion"
True. Try not to spoil it with fallacious mudslinging.
Posted by: bishop hill | March 11, 2007 at 07:39 PM
I'm a marine surveyor - a layman. To be blunt it is dissapointing to listen to people who clearly are informed on this subject spend their energies assulting and abusing those of a different persuasion.I dont want to witness this planets abiliy to sustain all life as a result of mankinds inability to grasp scientific evidence and act on it. Nor do i wish to see serious long term deprivation in the third world and huge tax increases in the west by following a course that is scientifically unsound.
Therefore does evidence support the documentry view that
1. co2 is not a serious greenhouse gas - that is water vapour plays a much greater role in heating the planet.
2. The % of total co2 production / year by mankind is dwarfed by other life forms and oceans etc.
3.Over millenium a rise in earth temperature has been followed by a rise in co2 concentration - not the other way round.
These statements are either right or wrong . I would like to know the ANSWER.
Posted by: adam moore | March 11, 2007 at 07:58 PM
False and True. It is true that water vapor is the strongest greenhouse gas in the atmosphere. But that does not mean that CO2 is not a serious greenhouse gas. One of the most common strategies of skeptics is to present such a simplistic view of things, that by claiming the greenhouse effect of H2O is much stronger than that of CO2 (which it is), they clearly imply that the effect of CO2 is negligible (which it is not).
True. For example, by present calculations the oceans give up about 90 GT (gigatons) of CO2 to the atmosphere per annum. But what the skeptics don't want you to know is that they also absorb about 90 GT per year. Natural emission and absorption are in equilibrium; the net contribution from the oceans is: zero.
This is another example of the dishonesty of so many so-called skeptics. They loudly proclaim (and you have obviously heard) that natural processes put more CO2 into the atmosphere than humankind, but fail to mention that they take as much as they give.
In fact, lately the ocean is no longer in equilibrium, it's taking in more than it gives off; the oceans are absorbing about half the CO2 emitted by human activity, and are acidifying in the process. Many regard this as a severe threat to marine ecosystems; some even regard it as a greater threat than global warming.
One of the false claims is that volcanism produces more CO2 than human activity. In fact the CO2 from human activity dwarfs that from volcanism.
The fact is that the reason CO2 is rising in the atmosphere is the burning of fossil fuels, without doubt. We know this not only because we can track the emissions from human activity and "balance the books." Fossil-fuel carbon has a different isotopic signature than carbon from natural processes, it's depleted in C-13 (because its origin is organic plant matter) and depleted in C-14 (because it's been buried for millions of years). The change in the isotopic signature of carbon in atmospheric CO2 matches precisely what would happen if -- and only if -- the source is the burning of fossil fuels.
During the transition from glacial to interglacial conditions, this is true. But again, the skeptics want you to believe in an oversimplified picture in which CO2 can cause warming or warming can cause CO2, but not both. Both factors are both cause and effect.
As for modern times (the "holocene," since the end of the last glacial about 11,000 years ago), CO2 has been quite stable at around 280 ppmv (parts per million by volume). Only since the industrial revolution has it changed dramatically, and that due to human activity.
Skeptic propaganda like the "swindle" documentary are very slick, and to those not in the know, they're very persuasive. But the amount of information they omit, and the implications they make which are patently false, are tantamount to fraud. You have indeed been swindled: by the documentary, not by climate scientists.
Posted by: tamino | March 11, 2007 at 11:04 PM
Sulphate aerosols causing cooling 1945-1970+ is a red-herring. The real cause of the global cooling 1945-1970 was the sun. Check out Sami Solanki's work for details.
Odd that the sun is still at a 7000+ year high, and we argue about the fleas on an elephants back. As the sun heats the oceans, it reduces solubility of CO2, we get more in the atmosphere. We are seeing the longer term effect of sustained enhanced solar activity.
(just one personal example, we didn't use to be able to see Aurora in California, over the last decade or two it has been an almost regular occurence.)
have a good day,
Robert
Posted by: Robert | March 12, 2007 at 01:57 AM
Oh dear, how the religious hold dearly to their beliefs, even when proven wrong. We are not the cause of global warming, get over it and find another moral plateau from which you can look down on the rest of us and make yourselves feel better, please? pretty please? your shaming our collective human intellect, and making me cringe for you.
Posted by: Phil Howe | March 12, 2007 at 02:07 AM
For those of you who are hung up on the so-called "Temperature leading CO2" effect offered in the faux climate documentary, here is a simple explanation for how you were fooled.
First we need to look at the original data. Here is a link to an graphical representational image of it taken from the Al Gore presentation:
http://i79.photobucket.com/albums/j160/noyards/Gore-Truth1.jpg
This presentation shows 650,000 years of data displayed onto an approximately 20 foot screen.
Now let's look at the presentation used in the "denial film". Here is a link to a screen capture from that film showing their take on the same data:
http://i79.photobucket.com/albums/j160/noyards/Clark-lie1.jpg
Now, this data represents about a 7,000 years subset of the Gore presentation (ie. It would take up about 2 inches of that 20 foot display were it superimposed on the Gore presentation.)
Here's a better image showing a red line to mark an exaggerated representation of the size of that "faux" data overlayed approximately where it should be located in relation to timeline and data size:
http://i79.photobucket.com/albums/j160/noyards/Gore-Truth2.jpg
Now, what you are seeing is a single location in the 650,000 year time line where, because of extenuating circumstances, caused by "de-glaciation", the CO2 looks to be lagging behind the temperature.
In order to be a valid theory, a lot more than 2 inches out of 20 feet of data would have to show this effect ... given that the opposite (19 feet 10 inches out of 20 feet) confirm the theory, which one is actually the more likely?
Come on folks, you've been scammed ... face up to it and move on.
Posted by: No Yards | March 12, 2007 at 03:41 AM
The links above seemed to be cut off, but anyone interested in seeing the images can simply "double-click" on the links, which should highlight the whole link, including any "hidden" parts, which you can then paste into your browsers address bar.
Sorry for the complication.
Posted by: No Yards | March 12, 2007 at 03:45 AM
No Yards
But everywhere I've looked, nobody is disputing that CO2 follows T. They just disagree about the reasons. (see Nathan's point 2 above).
Posted by: Bishop Hill | March 12, 2007 at 06:55 AM
Re point 2 in your rebuttal of the c4 documentary.I fllowed the link to Real Climate and have a problem.If there is a feedback loop ie some currently unknown process warms the planet causing more co2 to be released causing more warming causing more co2 etc .What breaks the loop? Wouldn't we end up as another Venus.
Posted by: mark fuggle | March 12, 2007 at 09:24 AM
>> For example, Vestas in Denmark have generated immense wealth by producing wind power generators.
I have to take issue with this statement. Wind turbines receive subsidies from governments that make them economical; without the subsidies the energy would be more expensive than that produced by coal.
Any industry can make money if the regulatory climate favours it. The wealth generated by Vestas and other makers of "green energy products" do not prove that there is more wealth to be made from being green than from being economical; it only proves that there is wealth to be made by extracting economic rent from the system.
I have yet to see any evidence that "green energy" is more efficient or will unlock more wealth than current forms. However, that is because far-from-green energy is able to pass on the negative externalities to the environment/society. The solution is not to subsidise favoured energy sources but to tax polluters.
Posted by: Tom Papworth | March 12, 2007 at 11:04 AM
I don't have much time to do comments today, but read this to see a post of why Earth couldn't become like Venus.
Posted by: Nathan Rive | March 12, 2007 at 11:05 AM
The BIGGEST problem with trying to get the general public to buy into ANY climate change theory is that the answer to it seems to be "raise taxes". Somehow, if I pay my government (UK) more money, the world will be a better place. I'm utterly unconvinced, as are the majority of my peers - due to the hypocritical waste our leaders and industrialists produce themselves.
As a reasonably intelligent member of the public (degree educated), I have yet to see a single, reasoned scientific debate on the FACTS of climate change. Showing me 40-year snippets of CO2 rise just makes me question the author, not accept the theory. Singling out transportation, be it car or aircraft, makes me question the goal (tax income), not my own travelling habits.
Trying to get the general public to seriously question their CO2 footprint will NOT be solved by taxation alone - and I object strongly to any suggestion otherwise.
Posted by: MikeH | March 12, 2007 at 11:13 AM
Tom:I have to take issue with this statement. Wind turbines receive subsidies from governments that make them economical; without the subsidies the energy would be more expensive than that produced by coal.
And coal hasn't received subsidies either? (link)
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