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Will Nitschke (www.capitaloffice.com.au) at 13:30 PM on 19 December 2007Less than half of published scientists endorse global warming
"The fact that so many studies on climate change don't bother to endorse the consensus position is significant because scientists have largely moved from what's causing global warming onto discussing details of the problem (eg - how fast, how soon, impacts, etc)." What you've written above may be true but unless you can back it up with research to support your statement, it's at best just your opinion and therefore not a reasonable counter-argument. In other words it's Klaus-Martin Schulte assessment versus yours, but at least one did research to support the stated opinion. "Two of the papers conduct no actual scientific research but merely review social aspects of climate science. I'm baffled as to why they would be included other than to "boost the numbers"" Because presumably the paper was focused on the opinions of scientists (remember?) and not just scientific research. I hope that resolves your confusion. -
Will Nitschke (www.capitaloffice.com.au) at 12:38 PM on 19 December 2007Mars is warming
Thanks for the response, but it appears you only want to take the argument up to a fixed point. What's caused the *increase* in dust storms that is leading to higher temperatures? Obviously not the more elliptical orbit of Mars alone as this hasn't changed. Which only leaves an extra-planetary explanation, doesn't it? Your explanation only makes sense if the temperature of Mars was not showing a trend increase. Storm activity would therefore be relatively consistent over time and the temperature on Mars would be relatively consistent over time. But it isn't. If this is wrong (which is quite possible of course), you need to explain how these storm cycles can last decades and lead to decades of warming, and then presumably afterwards, decades of cooling, only by means of interactions within the Martian atmosphere itself. -
Will Nitschke (www.capitaloffice.com.au) at 10:32 AM on 19 December 2007Mars is warming
You wrote: "Mars has one of the highest orbital eccentricities of any planet in our solar system which causes much greater seasonal changes than on Earth." OK, but has the orbit of Mars changed in the last 30 years or the last 100 years to explain the extra warming? If the answer is 'yes' can you explain why and how? If the answer is 'no' then doesn't that point to an extra-planetary explanation? It seems in your article you begin by ruling out the sun, then suggest you're going to offer alternate explanations, then fail to do so. Yes the storms can cause the warming, but what is causing the extra turbulence in the atmosphere leading to the storms?Response: The orbit wouldn't have changed over a 30 year or 100 year period - orbital changes occur over much longer periods. By orbital eccentricity, I mean Mars' orbit is more elliptical than Earth's which is more circular. This means Mars's distance from the sun changes more dramatically through a Martian year which means its seasonal changes are more dramatic than Earth's. I thought the alternate explanation was clearly explained - dust storms reducing the planet's albedo. -
Wondering Aloud at 03:18 AM on 19 December 2007Empirical evidence for positive feedback
I think what I am disagreeing with above is your contention that there is some great disconnect starting in the seventies. That is not evident in Tung's paper, nor is it as big a disconnect as 1940-1970 is from the AGW hypothesis. The sun climate correlation is not great but it does have a higher correlation than the CO2 climate connection. On your last paragraph you refer top your own positives and negatives page? There is a reason that warmer periods in the climate record are referred to as climate optimum. More than half of the surface area of North America, Asia, and Europe, is farther North than I am. Most of this land is very limited at the present for any significant agriculture. Currently far more people die as a result of cold related problems, (not just exposure) as due to heat waves. The idea that warming would cause reduced food supply and access to resources is not supported by the historical record. People are still not fighting for my beachfront property on Lake Baikal. Compare property prices on Lak Havasu and Lake Huron if you want to evaluate how people feel about too warm and too cold. Lake Huron is a lot nicer by any other measure. The economy as a whole does not share your preference for cold. -
jurrytusa at 00:39 AM on 19 December 2007Human CO2 is a tiny % of CO2 emissions
Some additional ball park figures. According to http://en.wikipedia.org/wiki/Carbon_dioxide 385 ppm corresponds to 3e12 tons of CO2 in the atmosphere, so we get: year ppm tons 1970 320 2.49E+12 2005 385 3.00E+12 5.06E+11 increase apparently the manmade carbon flux has risen from 4E+09 to 8E+09 tons from 1970 to 2005 so on average a flux of 6E+09 for 35 years is 2.10E+11 tons which is 42 % of the total increase and 7 % of the current total atmospheric CO2. That begs the question, what is the cause of the other 48 % ? And how can a manmade increase of 7 % be the main reason for a global increase in temperature? -
Will Nitschke (www.capitaloffice.com.au) at 00:34 AM on 19 December 2007Satellites show no warming in the troposphere
Why start the trend line at 1982(?) Why not 1980? Or 1995? Wouldn't the trend line be pointing downwards then? Isn't playing with statistics fun? ;-) -
jurrytusa at 21:59 PM on 18 December 2007CO2 lags temperature
I have two questions regarding this "CO2 lags temperature" argument. You say that the Milankovitch cycle is to weak to explain the big temperature difference and that it requires strengthening through energy absorption by means of CO2. How do we know that CO2 is the main cause and not something else, e.g., the change in Earth's albedo due to ice and snowcover ? Also you say that it is not fully understood how oceans give up CO2. What about the reverse, the removal of CO2 from the atmosphere when the Milankovitch cycle drives the temperature down ? Hope you have time to answer these. -
jimdk at 20:13 PM on 16 December 2007Empirical evidence for positive feedback
Scientists are also seeing a net negative feedback Time series analysis results on the basis of 24 long temperature series from various European and Asian stations do not support the IPCC conclusion about the dominant role of positive feedback (e.g Soden and Held 2006) as long as the cumulative feedback sign is considered. Vice versa, the variability of the air temperature at these stations during the last centuries shows that the influence of growing CO2 concentration in the atmosphere has been totally eliminated by the system’s negative feedback. One can expect that the IPCC used four key feedbacks represent too weak tool to properly describe the cumulative effect of all actually operating feedback loops in the climate system. Its results are therefore not relevant for understanding the current climate system variability. http://www.aai.ee/~olavi/EE2007-ok.pdf -
Wondering Aloud at 04:46 AM on 14 December 2007Svensmark and Friis-Christensen rebut Lockwood's solar paper
I can see why you say it reads like an oped but that isn't very distracting. My question is are they wrong? I remember thinking that the Lockwood results seemed strange to me relative to what I knew of the recent history of solar activity.Response: The oped comment is about as ad hominem as I get (I try to avoid ad hom criticisms which rarely contribute anything useful) - just to register my surprise at the tone of what is meant to be a scientific rebuttal. As for Lockwood, the most controversial element of his paper is that it was even published - generally when you publish a paper, it adds something new to the body of knowledge. Lockwood is covering ground well trod by Ammann 2007, Foukal 2006, Scafetta 2006, Usoskin 2005, Haigh 2003, Solanki 2003, Stott 2003, Lean 1999, Waple 1999 and Frolich 1998 who all find the sun has contributed minimally to global warming over the last 3 decades. -
Wondering Aloud at 02:33 AM on 14 December 2007Empirical evidence for positive feedback
You mention here Tung and Camp, in a paper by Camp and Tung published in Geophysical Research letters volume 34 this year, these same two authors found a link between total solar irradience and temperature change including a short time lag. I suspect this is part of the same research. If this research is valid than one of the things it suggests is that total solar irradience explains a significant chunk of late 20th century warming, perhaps all of it detected by satellite measurements. While this research may support your point here it is somewhat contradicting your argument in the "it's the sun segment." From reading your link it appears to me that they are showing a positive feedback for total solar irradience changing. This is likely to mean CO2 would also have a positive feedback but it is not actually evidence of that. As the sun varies the amount of energy reaching us varies not only in amount but in distribution of wavelengths. Since high solar activity correlates with higher temperatures it may be that UV of x-ray radiation have a larger proportional affect on climate than visible and IR. If so they would also have a place to look for a mechanism for the phenomena they report. Am I the only one out here who is waiting hopefully for global warming? We are having a heat wave, warmest day in weeks at -8.Response: Tung's work looks at the short term effects of solar variations. Eg - over the 11 year solar cycle. Global warming is a multi-decadal trend and so to find out how much the sun is contributing, you need to look at the long term trends of solar variation. And studies on the long term trends (Usoskin 2005) show that in the past, long term solar trends have correlated with climate but the correlation ended in the mid 70's when the modern global warming trend began. It's past correlation coupled with the break down in correlation that tells us the sun cannot be the main driver of global warming.
UV does have an amplifying effect but as with Total Solar Irradiance, the UV long term trend over the last few decades is small. This is especially significant as UV typically shows greater variation than TSI.
I'm sure there are people who benefit from global warming, particularly in high latitudes. But compare the positives to the negatives to see if overall, global warming is a good thing. -
Wondering Aloud at 09:04 AM on 13 December 2007Temp record is unreliable
How do NASA and GISS claim to remove UHI effects? The term Urban heat island is probably not a good one it is a land use issue not simply an urban issue. A station in NYC central park may be just fine while a station in the middle of nowhere can be bad if it is placed on asphalt next to an air conditioner exhaust. Last month, Energy and Environment 18:985-995, published a not very kind report by Douglass J Keenan. It shows that two well known and influential papers, that are still the basis for the IPCC claim that UHI has been removed from the global climate data sets, are in fact incorrect. In fact the word used is Fraudulent. While Tom Wigley has sent me some references on sea temperature that seem pretty robust, (thank you sir) the land surface temperature measurements are in serious trouble. It looks to me like at least half of the late 20th century warming signal in this data is about to vanish. We really need a data set that is not badly contaminated, that uses sites that are properly placed and maintained, USHCN is not it. -
Wondering Aloud at 06:43 AM on 13 December 2007Evaporating the water vapor argument
Continued study. Very recent but I didn't write down all the details so you may have to dig a bit. Spencer etal in Geophysical Research letters Vol 34 have a paper on Rainfall events in the tropics. It appears to clearly show empirical evidence on Lindzen's proposed "iris effect" of water vapor. In addition to being very important to how storms develop over time, it appears to reduce any positive effect of increased water vapor on temperature by about 75% -
brewski at 19:58 PM on 7 December 2007Al Gore got it wrong
The British high court sided with schools, allowing the screenings of An Inconvenient Truth to continue. The court ruled the film was accurate in its four main scientific hypotheses, "each of which is very well supported by research published in respected, peer-reviewed journals.” The court challenge was funded almost entirely by a mining concern owned by Robert Durward, a long-time critic of environmentalists. -
Wondering Aloud at 06:27 AM on 7 December 2007Temp record is unreliable
If what you say is true than McIntyre's error is in conceding that the sites in the US are good. I believe what he is conceding is that they are likely to be better or at least no worse than elsewhere. http://wattsupwiththat.wordpress.com/ So far, with 40% of this supposedly gold standard network surveyed, 85% of sites are showing errors in the site and operations that are likely to be > 1 degree C. In other words larger than the entire GW signal to date. People promoting catastrophic warming scenarios frequently refer to graphs from this very data set to support their claims. It is clear that we just can't make a useful reconstruction of surface temperatures using these sites. I am somewhat dismayed by the idea that modeling with supercomputers is somehow climate research. While going thru and evaluating actual data and methodology is apparently not what "real researchers" do. I could have saved so much time in grad school if I had only known that computer models were real research and the actual data wasn't. Modeling is a valuable tool in science but the models are not evidence in any way of what is happening in the climate. Adding the word supercomputer does not make it science, in fact quite the opposite. By the way since Cray isn't making them anymore what makes a computer super these days? -
cce at 17:21 PM on 6 December 2007Al Gore and Dr Thompson's thermometer
It is "Likely" (~66%) warmer today than it was in the "MWP." That was the conclusion of the NAS, since "someone" asked. It was also the conclusion of the TAR, by way of the Hockey Stick, which is how this whole thing started. Now, setting aside the fact that MWP vs modern temperatures comparison isn't the basis for AGW theory, let's assume that AGW is only 66% probable, and not the >90% that the alarmist Saudi Arabia and Condoleezza Rice concluded in AR4. In constrast, what is the probability that your house is going to burn down? Just think of what you could do with all that money wasted on insurance. Mmm. Money. Or let's say a bunch of drinking buddies bet you to stick a gun in your face. Only one bullet in the chamber. Spin the chamber. Pull the trigger. Win a $1000 bet. Only a 17% chance of shooting yourself in the face. Just who wouldn't take that bet? -
nanny_govt_sucks at 12:51 PM on 4 December 2007Al Gore and Dr Thompson's thermometer
"likely"? Are you going to hang our prosperity on the term "likely"? If "likely" is the best you've got then certainly more study is needed before implementing any "solutions".Response: The "hockey stick" is hardly the sum of the evidence for anthropogenic global warming (in fact, a fairly minor piece of the puzzle). There are multiple lines of evidence to show humans are causing global warming including many independent climate model studies. Or if you turn your nose up at models, peruse the empirical evidence. -
birdbrainscan at 09:37 AM on 4 December 2007CO2 lags temperature
This discussion goes on as if the only evidence we have to decide whether CO2 has a warming effect is the paleoclimate data. That's a very, very narrow perspective. What everyone needs to appreciate is that we have fundamental physics and really, really extensive laboratory analysis of the absorption spectra gases alone and in combination, at all sorts of temperatures and pressures. You can look up the raw data on HITRAN at http://www.cfa.harvard.edu/hitran/ and you can read the conclusions drawn from this raw data about the greenhouse effect at, e.g. Ray Pierrehumbert's free access draft of his "Climate Book" http://geosci.uchicago.edu/~rtp1/ClimateBook/ClimateBook.html This is a university level physics textbook, not aimed at the general public. If you need more basic accounts of how GHGs absorb infrared, you can check out www.realclimate.org where Dr. Pierrehumbert is an active contributor. I'm linking to the academic text just to point out that belief in CO2 being a greenhouse gas, able to *cause* warming as well as respond to warming, is built on over a century of physics and lab analysis, and really, really NOT just on a few graphs taken from ice cores and put up on the screen by Al Gore. Way too much online discussion has treated this as if the whole line of reasoning rested solely on the paleo graphs and nothing else. To sum it up: temperature changes do indeed drive CO2 changes, *and vice versa*. The positive feedback between the two accounts for how ice age terminations get moving so much faster than the very gradual Milankovic forcings. The feedbacks don't run away forever because, for one, the carbon dissolved in the ocean is not infinite, the ice albedo feedback runs out when the glaciers and sea ice have retreated, etc.Response: Thanks, very pertinent comment and the link to Pierrehumbert's page is useful, particularly the latest draft of his upcoming Textbook on climate. Down the track, I hope to update this page fleshing out the point that CO2 warming is not dependent on ice core records but on fundamental physics (yet another on the to-do list :-) -
Alan McIntire at 14:08 PM on 1 December 2007Empirical evidence for positive feedback
One of Pielke's posts pointed out the differing effects of CO2 and water vapor. http://climatesci.colorado.edu/2006/05/05/co2h2o/ Here's a paper by Minschwaner, indicating that many models overestimate the postive feedback of water vapor, and that the actual warming would be more in the range of 1.2C to 1.6 C. http://meteo.lcd.lu/globalwarming/water_vapour/dessler04.pdfResponse: Thanks for the comment. The Minschwaner/Dessler paper is an interesting one - it led me to a list of the publications by Andrew Dessler. As well as many studies on water vapor, it includes Minschwaner 2006 which concludes "current global climate models are simulating the observed behavior of water vapor in the tropical upper troposphere with reasonable accuracy." Added to my to-do list is going through all of Minschwaner/Dessler's studies as they seem to be some of the leading authorities on the role of water vapor in climate. -
sherro at 21:24 PM on 28 November 2007Human fingerprint on atmospheric CO2
What, then, is the total weight of Carbon dixide in the atmosphere and what weight is calculated to have been produced by burning fossil fuels? Does this method of analysis distinguish between CO2 released from burning fossil fuels and "old" CO2 produced from the decay of corals? In what proportion? -
sherro at 21:22 PM on 28 November 2007Al Gore and Dr Thompson's thermometer
You forgot to note that Al has his Y axis upside down and that his zero line did not go through zero. Some graph, so great is was the thematic for the IPCC?Response: At the risk of repeating myself, I'll reiterate that while Al Gore's graph has some flaws, his main point that modern times are the warmest over the last millenia are backed up by multiple studies, the NAS and NOAA. -
cce at 18:58 PM on 22 November 2007Al Gore and Dr Thompson's thermometer
"Our conclusion is that this recent period of warming is likely the warmest in the last millennium." NAS supports '98 global warming evidence -
kenton at 09:58 AM on 22 November 2007Evaporating the water vapor argument
Philippe, your chemistry is a little askew. Natural oxidation of methane is a chemical process which I don't believe would fall under your definition of burning, yet has the same chemical equation. Why isn't that adding water vapor to the system? Or respiration, or a gazillion other processes occuring all over the globe on, under and above the surface, continually removing and adding water to the atmosphere in a wonderfully dynamic process, varying over hours and millenia, over elevation and geographic location, in ways that we continue to struggle to accurately model and understand. Despite what John would have you think in the analysis above, more than one climatologist is continuing to study the effect of water vapor on global climate. To blithely state that the global atmospheric water vapor content is essentially a simple function of global temperature because it is governed by the Clausius-Clapeyron relation (John, is that an unfair paraphrase?), should make a climatologist wince. For example, this relationship is approximately true only near the ground-- and only higher altitude (free troposphere) water vapor effects earth's cooling (precisely because it is colder than the earth), and up here, water content is governed not by C-C relation, but by transport processes such as the rise/fall of warming/cooling air. I can give references. In fact, a quick google just pointed me to IPCC TAR Ch7.2.1 Physics of Water Vapor and Clouds. John, although I find your site a delight and in general think you have the right mind-set, you shouldn't over-simplify just to show up the global-warming skeptics. Or you may fall into a similar trap as Philippe and over-extend your reach attempting to bolter to eagerly your already-held belief. Specifically, here I think you are attempting to stifle a scientifically-valid continuing attempt to understand a complicated process, by prematurely asserting the issue is resolved, with a simplistic and/or flawed line of reasoning. A trait I greatly fault Al Gore for sharing. Regards, KentonResponse: Good feedback, kenton. I'm not saying we should stop studying water vapor systems - if I give that impression, I'll revisit my words. In fact, I think climate will never be completely understood - there'll always be nooks and crannies to further understand. But I do believe we know enough to act on reducing CO2 emissions.
Re over-simplification, that's a framing issue I'm still working out. I'd like to make the science accessible without compromising scientific accuracy. The point of this page is not to say water vapor is completely understood but that rather than contradict anthropogenic global warming, it is actually consistent with it. But I will have another look at my treatment of the C-C relation so thanks for the feedback -
nanny_govt_sucks at 11:06 AM on 21 November 2007Al Gore and Dr Thompson's thermometer
Other reconstructions tell a different story. See http://www.ncasi.org/publications/Detail.aspx?id=3025. By the way, is the NOAA the last word on climate of the last millenium? Why do you pick them as an authority over the NAS, for instance? -
Wondering Aloud at 01:03 AM on 21 November 20071934 - hottest year on record
Also the graph here only goes back to the end of a 30 year cooling period. And establishes this as the zero point.Response: The point of the graph is to show the miniscule difference before and after the "Y2K correction". The reason it only showed the last 30 years was because if you display an even longer period, the difference is even harder to detect. Here is the same data going back to 1880 (again courtesy of Tamino):
The difference between the temperature record before the Y2K correction (red dots) and after the correction (black diamonds) is insignificant anytime before 2000 and still barely noticeable after 2000. The change has had practically no detectable impact on the global warming trend over the past 30 years. As for the zero point, temperature anomaly graphs take an average over a specified period (eg - 1960 to 1990) - the temperature anomaly is the difference from this average. The period selected is arbitrary (GISS and CRU use different time periods) as the trend will be the same regardless.
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Wondering Aloud at 01:00 AM on 21 November 2007It's not bad
Malaria spread? It already reaches the Arctic circle how much more could it spread? I know tongue in cheek but some of these things are mutually exclusive. -
Wondering Aloud at 08:56 AM on 20 November 2007Did global warming cause Hurricane Katrina?
Well you could start here... Though there are many others. What many of them say is that warming has not increased intensity or frequency. Free, M., Bister, M. and Emanuel, K. 2004. Potential intensity of tropical cyclones: Comparison of results from radiosonde and reanalysis data. Journal of Climate 17: 1722-1727. However since CO2 is supposed to produce warming primarily in cold dry air, the models I am familiar with predict that the poles should see the most significant warming. As temperature differential between the tropics and the poles is a major driving force of cyclonic storms a decrease in the differential should lead to a decrease in storm intensity. Prior to Katrina the relatively low number of major hurricanes in recent years had been seen as evidence that the models were right. I have looked at a number of papers and while 15-20 years ago I would have said warming should increase system energy and therefore intensity, I think I was wrong back then. It seems pretty clear that frequency and intensity have not increased in the last 70 years, if GW theory predicts they should this would in fact be strong evidence against it.Response: Thanks for the link - interesting that the 2004 paper is co-authored by K Emanuel who wrote the 2005 paper that is the primary evidence linking greater SST to hurricane intensity. There's more to this, I'll see what I can track down. -
Wondering Aloud at 06:27 AM on 20 November 2007Are we heading into a new Little Ice Age?
No, I was commenting on the size of the feedback effects predicted for CO2 caused warming. We are assuming that feedback will be positive and magnify the warming effect of the CO2. In the last 3 IPCC report the magnitude of these feedback effects was predicted to be 3-4 times what can be justified from observation, and the error bars have been huge. Without a large positive feedback effect there is really no way CO2 alone could cause enough warming to be any big deal. I don't know what assumptions the people trying to explain solar effects are using. However, the reason the predicted rise from CO2 is so large is because in the case of the CO2 they are assuming a large positive feedback that cannot yet be verified from observation. If, as the evidence suggests, the feedback effects are less than a third of what is predicted in the IPCC reports; than the amount of warming expected is much reduced. Since I like to end with a question, I can think of a way off the top of my head to cut CO2 emissions in North Amerrica by 50% in the next 10-15 years at zero net cost to the economy and with no new technology needed. If people in policy making positions are convinced of this impending disaster why are they wasting time with useless expensive junk like cap and trade and the Kyoto protocol?Response: Off the top of my head, I can think of several strong pieces of empirical evidence for positive feedback. Soden 2001 and Santer 2007 both use observations of atmospheric water vapour to confirm the positive feedback nature of water vapour (more on water vapour). And a climate sensitivity of around 3°C (which would require positive feedbacks to be that high) is empirically confirmed by Hansen 1993, Lorius 1990, Hoffert 1992, Gregory 2002 and Tung 2007 (more on climate sensitivity). But funny you should bring it up - I'm actually working on a new post describing other empirical observations of positive feedback (a followup to the model uncertainty post) - I'll post that within a week or two. -
StanislavLem at 17:21 PM on 16 November 2007Models are unreliable
I recommend this paper and it references for this section as well http://members.iinet.net.au/~glrmc/2007%2005-03%20AusIMM%20corrected.pdf -
StanislavLem at 16:37 PM on 16 November 2007CO2 lags temperature
All of the conclusions you make in your rebuttal of the skeptics argument are valid only if the Milankovitch cycles (which as you note provide relatively weak forcing) are indeed the sole cause for this whole process. This seems like a big assumption to me and I don't think the science behind that has been settled. Most of people sort of automatically assume it, but there are number of scientists starting with John Imbrie (the guy who led the whole CLIMAP effort and published the infamous Ice Ages: Solving the Mystery) that say Milankovich cycles (Earth's orbital variations and such) seem to explain only 50-60% of the whole insolation variance. So, adjusting one's model only using insulation curves generated by orbital modeling as they do in the papers you mention seems unjustified to me. In essence, the authors of the above papers precondition themselves to look only for models that fits their believes (that are only limited to Milankovich cycles as a driver). There are many other additional hypothesis that also make sense even though their quantification is not as simple as just writing an orbital mechanics models which is all nice and simple with nice math functions. A major examples for additional forcings on these time scales include changes in the solar irradiation due to the long-term manifestations of the solar activity that are ought to be much bigger that what we've observed with satellites for the past 20 years (I refer to the TSI measurements) and are not only related to the TSI, but to things like the solar diameter, the solar wind and its interactions with Earth's magnetic field and many other process on the Sun and inside the Earth's core. Many things in the Solar System seem to work in synergy. So, that many cycles and superpositions of cycles of completely different physical processes external or internal to the Earth's climate have similar length and appear as if only one factor is at work when in fact there are several. I acknowledge that there is the Occam's razor that advocates simplicity, but I don't necesesarily think it is the best approach when we are considering Earth's climate and the near-Earth environment. So, I wasn't really asking about the lags, but whether we can even begin to consider that these lags mean anything. As far as the error bars, I was asking for the errors of the reconstruction models that create those curves on the graphs you show. The lines only follow the positions of the 50% quantile of each model output point but tell us nothing about its possible range (due to original measurement errors and other uncertainties).Response: There's still a lot to be worked out re the whole mechanism of deglaciations. For example, there are various theories on what causes the CO2 increase after temperature increase, the most accepted theory being degassing from the deep ocean. I've read of theories that the 100,000 year cycle is caused by solar variations rather than orbital changes although the Milankovitch theory seems to be more established and confirmed by at least several papers I've read. But the main point of this page is to answer the argument that "the CO2 lag debunks anthropogenic global warming". The current scientific understanding of the CO2 record (and the papers quoted in citing CO2 lag) state that the CO2 lag confirms the warming effect of well mixed atmospheric CO2. -
StanislavLem at 15:34 PM on 16 November 2007CO2 lags temperature
First of all, John, thanks for spending the time to create and maintain this site. I do realize it must be quite substantial time commitment. Although, it is not exactly neutral and is somewhat driven by your current opinion that GW is mostly due to anthropogenic CO2 emissions, the forums on the site are still one of the few places where we can have some more meaningful debates based on some scientific thinking and facts. So, in some respect the website is just like Churchill's quote on democracy (I think, he is the right man to quote since as you've correctly noticed many things in the GW debates on both sides are politically motivated consciously or not): "It has been said that democracy is the worst form of government except all the others that have been tried. " Of course there are another two quotes from him that I think very much apply to the GW debate: "The best argument against democracy is a five-minute conversation with the average voter. " & "A lie gets halfway around the world before the truth has a chance to get its pants on." Well, enogh quotes. On a more serious note, sadly enough, the whole field of Climate Science and Global Warming has become just like Finance. There is so much easy money flowing around that there is a great number of people with all sorts of backgrounds and levels of knowledge that have no relation to climate/physics or anything distinctly related (although by all means I am not saying we should only used established scientists' work as a guideline) that would make most outrageous claims/predictions with arbitrary certainty backed up many low-quality science booklets/papers/reports, posh presentations and heavy media support to streer more funds their way. In general, what I'm refering to is the so-called "press release science", unfortunately endemic to so many other fields besides climate. And finally, refering to the following quote from your bio section: "I'm still yet to meet a skeptic argument that is even vaguely convincing." I would suggest looking at some arguments that come from people that don't exactly fit the typical skeptic stereotype you describe, for example take a look at this list http://www.warwickhughes.com/hoyt/climate-change.htm and the following scorecard on the same website http://www.warwickhughes.com/hoyt/scorecard.htmResponse: Love those quotes from Churchill. I must confess, I'm not particularly impressed with Warwich Hughes' climate change page which reads a lot like my Skeptic Arguments page (except mine is more comprehensive :-) His scorecard is interesting - if I have more time after maintaining this site (and responding to your comments), I'll give it a closer look. -
John Cross at 04:41 AM on 16 November 2007Mars is warming
StanislavLem: An interesting post, but even better for me is that it lets me play skeptic for a change ;-) . You do not specify what viable hypothesis explain how non-TSI manifestations of solar activity cause dust storms on Mars, so I can not address that, but I do not agree with your idea that the Martian atmosphere is a good test bed to allow observation of the effect of human activity. Off the top of my head, here are 4 major differences and, in my opinion, each one is enough to invalidate such a comparison without a large amount of research (i.e. several continuous martian weather stations). 1) No magnetosphere so there is a direct ionization of atmospheric particles. 2) I would disagree with your comparison about pressure. If you are looking at total atmospheric pressure, then Mars is more like the stratosphere. If you are talking about partial pressure of CO2, then the surface of Earth is the best we can get, but that is even too low. In any case, both of these do not produce some of the more important effects such as pressure broadening of the CO2 absorption spectrum. 3) There is no water to speak of and thus the vertical thermal transport associated with water does not exist. 4) Finally, the drivers also seem to be much different. Dust storms are a key part of the Martian climate as are sublimation winds from the poles. These have no equivalent on earth. Regards, John -
Wondering Aloud at 03:14 AM on 16 November 2007CO2 lags temperature
No, the American Chemical Society Conference at which I noted this discrepency in a presented paper was in 1989 because I was in Grad Chemistry courses at the time, so I much doubt that it was 2001 or 2003 data. Other than that I hope you're right because otherwise 1)we are being led down the primrose path and 2) I am freezing my butt off up here. The presenter after having this error spotted by a lowly physics type grad student was not well recieved in the question session by the roomful of chemistry PhD's that were present. None the less his hypothesis that CO2 causes global warming is still widely discussed. :)Response: I would be surprised if ice core records were of sufficient resolution back in 1989 to clarify CO2 was lagging temperature - it's only been more recent ice core records that have been of high enough resolution to clarify the CO2 lag. Spencer Weart has published a great online history of ice core measurements that is well worth a read.
Without knowing which older studies you're talking about, the most recent studies with up to date (and dare I say the most accurate) data (Monnin 2001, Caillon 2003) paint a similar picture of Southern warming -> CO2 rise -> Northern warming. But if you do know of any pertinent older papers, it'd be great if you could post the links here. And kudos for sticking it to the man :-) -
Wondering Aloud at 01:14 AM on 16 November 2007Models are unreliable
Models are the biggest gun in the arsenal for AGW. What people like Dyson are telling us is that the models use assumptions that are not validated by observation and that cannot account for many known effects. The models might be right but they haven't got a good track record except in hind sight. (After they've been fudged to fit the past) Someday they will probably be good they are better than 20 years ago. -
Wondering Aloud at 01:05 AM on 16 November 2007Climate's changed before
Thanks for trying to answer science with science. Most sites on the subject are propaganda vs science or propaganda vs propaganda. -
Wondering Aloud at 05:05 AM on 15 November 2007Are we heading into a new Little Ice Age?
..."the change in forcing even if in the extreme case of a Maunder Minimum is less than the forcing from CO2. ]" Doesn't that depend on whether or not the size of the feedback effects, that are supposed to magnify the CO2 forcings, are correct?Response: It doesn't matter - feedback is dependent on temperature rise, not the nature of the forcing. The feedback from 1 degree of solar warming would be the same as the feedback from 1 degree of CO2 forcing. -
Wondering Aloud at 04:54 AM on 15 November 2007It's cosmic rays
I always thought this hypothesis seemed unlikely, but... What about the last 10 years of global not warming? Why does CO2 get an 800 year wrong direction lag and the sun has to be exactly in step to be a viable hypothesis?Response: The point is that because the sun has correlated so closely with temperature in the past, when the correlation ended in the 1970's, it's reasonable to conclude some other forcing imposed itself on the climate. Re the CO2 lag, the ice core records actually confirm the amplifying effect of atmospheric CO2. As for the last 10 years of global not warming, you'll find the warming rate is the same over the last 10 years as over the last 30 years. -
Wondering Aloud at 04:45 AM on 15 November 2007CO2 lags temperature
RE: response Are we sure about that? I am sure the original data from way back then was actually from Greenland ice cores, showing that temperature was rising before CO2, there as well as in the Antarctic. The Antarctic data was not yet around. If CO2 is rising first in Greenland than your hypothesis may be correct. I know CO2 is supposed to cause warming, and I think I understand why. But, the data still seems to scream corelation does not equal cause and effect.Response: The "original data from way back then" was probably Monnin 2001 which used the Dome Concordia ice core or Caillon 2003 which used the Vostok core - both are from Antarctica. Caillon concludes "The sequence of events during Termination III suggests that the CO2 increase lagged Antarctic deglacial warming by 800 ± 200 years and preceded the Northern Hemisphere deglaciation." More recently, Stott 2007 found that tropical temperatures lag southern warming by ~1000 years. I agree with you - correlation does not necessarily imply causation. But the ice core record is consistent with the warming effect of CO2 and explains both the degree of deglaciation and how a localised warming (increased insolation in the south) spread across the globe. -
StanislavLem at 13:55 PM on 14 November 2007CO2 lags temperature
Provide error bars for the reconstructions, they tell quite a different story. Error bars are always necessary for meaningful interpreration of graphs like this.Response: Not sure what your point is - are you disputing that CO2 lags temperature? Monnin 2001 doesn't display error bars but quantifies the lag as around 800 ± 600 years:
Caillon 2003 constrains the CO2 lag to 800 ± 200 years (but again, no error bars):
Stott 2007 finds similar results - a CO2 lag of 1000 ± 300 years. Stott does include 200 year uncertainty on the benthic ages (in fact, Stott's graph includes everything but the kitchen sink):
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StanislavLem at 13:52 PM on 14 November 2007Mars is warming
Sunspot numbers are extremely crude indicator of solar activity and do not encompass many other manifestations of it (sorry adding the F10.7cm Radio Flux Index also won't do the trick). So repeating the argument that sunspot numbers have leveled out since 1950 doesn't necesseraly mean what you want it to mean (no additional inputs from the Sun in the Earth's or any other planet's climate). Also, focusing only on the total solar irradiance (TSI) as the only possible way in which solar activity influences Earth type planets' climates is just selective presenting/lack of knowledge (I hope it is the second, since the first would imply very bad things about your presentation of facts). In fact, there some quite viable hypothesis that explain how non-TSI manifestations of solar activity cause dust storms on Mars (by the way those are possible for the Earth as well). Obviously there is still to little data to confirm or reject them. By don't "get rid of" Mars just yet. Mars is actually quite good "test case" for the anthropogenic vs. natural warming debate. As a planet it is quite similar to the Earth in many important aspects and it is as close as ti the Earth as it gets in the solar system. Some of the main advantages for a possible "Mars test case" are: 1. There is no human activity there to influence the Marsian climate in any way, so we can discount that factor 2. there is no ocean to provide huge termal inertia, so solar effects will be much more immediate, 3. Marsian day is almost identical to Earth's day, 4. Marsian atmosphere is similar Earth's mid upper atmosphere, so this simplifies estimation of the solar effects quite a bit. The geometrical effects that you mention (orbit's eccentricity, axis tilt) are quite easy to correct for, much easier that cloud structure in the current climates for example. -
StanislavLem at 13:08 PM on 14 November 2007Are we heading into a new Little Ice Age?
Consensus statements are meaningless in general, they are sort of popularity contest of who is more loud and famous, and who's got the biggest grants (not necessarily the best science). There's at least 2-3 solar models that have quite good track record at predicting coming solar cycles based on various patterns that hold quite well over time (i.e. statistically significant), some include physical mechanism and some are based on statistical relationships. We have much longer and better records for solar activity that for Earth's climate and they allow for much better verification. You can start with Sabatino Sofia's models, there are other less known as well. In conclusion: The graph you posted up there is quite misleading because it doesn't distinguish between quality of various models.Response: The point of mentioning "consensus" is that there is actually very little in the way of a single consensus position - that the solar prediction panel predicts either greater or smaller tells us little. But once again, the point is moot - the change in forcing even if in the extreme case of a Maunder Minimum is less than the forcing from CO2. -
nanny_govt_sucks at 06:24 AM on 13 November 2007Al Gore got it wrong
Al Gore also got "Dr. Thompson's Thermometer" quite wrong (please see http://www.climateaudit.org/?p=2335 for more) 1. The y-axis is inverted so the graphic actually shows temps are _cooling_ not warming! 2. The graphic is actually a reconstruction from Michael Mann, combined with Jones' CRU data, and not Thompson data at all. 3. The graph is centered at 0.5 instead of 0. It is also interesting to note that prominent AGW credulist Tim Lambert knew of these errors yet said nothing as revealed in the comments in this post - http://www.climateaudit.org/?p=2328 . It makes one wonder why Mann and Thompson did not say something about the misrepresentation. Perhaps they did not see the movie?Response: Thanks for the links - I've added a new post about Dr Thompson's thermometer. -
emmac at 23:35 PM on 11 November 2007Are we heading into a new Little Ice Age?
Thats a bummer, i was looking forward to a little ice age and thinking about how to prepare for one, todays society needs to be knocked down a peg or two. -
emmac at 08:45 AM on 11 November 2007Are we heading into a new Little Ice Age?
Is it possible that cycle 24 won't get very big at all and we could be entering into a maunder minimum now?Response: Anything's possible but it's very unlikely that the next cycle will be a Maunder Minimum which was a rare occurance of no sunspots for a number of decades. The most likely predictions for the next cycle are slightly less than usual or slightly more than usual. However, the pertinent point is even if we did enter a maunder minimum, the forcing from CO2 emissions far outweighs the change in solar forcing. -
joan lorraine at 11:08 AM on 10 November 2007Did global warming cause Hurricane Katrina?
No Al Gore does not get a pass on Hurricane Katrina. He clearly implies in his book and never once qualifies it that Katrina was caused by global warming. Katrina was a Category THREE -- count it -- Three hurricane when it hit New Orleans. This is far less intense than many of the worst hurricanes that the Gulf has historically produced. It also hit a city that was an accident waiting to happen: the result of decades of poor infrastructure maintenance and bad urban planning. Those who suffered the most in New Orleans -- poor people of color --deserve better than to have a group of elite white men prey upon their suffering to further their own agenda. The scientist who argues that we are currently seeing more intense hurricanes due to global warming, Kerry Emanuel, also wrote: "it would be absurd to attribute Katrina to global warming." The storm wasn't what caused the disaster, but I imagine that FEMA, the city mayor, and La's governor are all thrilled to be exonnerated by you. Where on earth is the liberal conscience here. What Al Gore wrote in the book where Katrina is concerned (which I understand captures almost word for word the film) is propaganda pure and simple. This does nothing for the cause of global warming, and the people of New Orleans deserve better. -
Wondering Aloud at 06:54 AM on 10 November 2007There is no consensus
Roverdc hits the nail on the head. To say there is bias in the science at this point is a wild understatement. What the public hears is claims that "all scientists except a few kooks agree that catastrophic global warming is immenent and caused by your car.". This is what they think you mean by consensus. Is it safe to say the real consensus is closer to the view of those so called deniers in the National Post series or to the alarmist panic that is being widely circulated through things like "An Inconvenient Truth"? -
Wondering Aloud at 06:42 AM on 10 November 2007CO2 lags temperature
It is reasonable that warming of the oceans is in fact causing CO2 increase in the paleo record. What I wonder about is how anyone can turn this into evidence that CO2 causes warming? When I first saw this at an ACS function nearly 20 years ago these curves were presented as proof of CO2 caused warming; despite the obvious fact that the graphs, even then, showed that the temperature change was not following but rather was leading the CO2 change. Now we are trying to explain away T changing first invoking creative models. It appears the fundamental premise that CO2 causes warming is simply not supported by the paleo record. It may still be true, but what evidence do we have in the climate record that supports this hypothesis? Here is another question: If ice ages are on 100,000 year cycles because the Earth's orbit is more elongated on 100,000 year cycles why is the Earth's orbit so round now? Shouldn't it be nearing maximum excentricity?Response: The paleo record shows that Antarctic temperatures rise about ~800 years before CO2 and Greenland temperatures rise after the CO2 rise. The CO2 warming effect is necessary to explain both how weak orbital forcing can get us out of an ice age and also how an orbital forcing that affects only southern areas can spread through the globe. The paleo record also enables us to compare Co2 forcing with temperature change to calculate climate sensitivity. -
Dave Rado at 09:57 AM on 3 November 2007Mt. Kilimanjaro's ice loss is due to land use
I've found a better link re. the Himalayas: Himalaya Ice-Melt Threat Monitored in Nepal, National Geographic News, which includes the following:For example, researchers at the National Institute of Hydrology in Roorkee, India, estimate that reduced glacier meltwater would cut July-through-September river flow of the Ganges by two-thirds. This decline would leave 500 million people and 37 percent of India's irrigated land short of water. Himalayan glaciers also feed six other of Asia's great rivers—Indus, Brahmaputra, Salween, Mekong, Yangtze, and Huang Ho—putting communities across this region at risk of water shortages.
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Dave Rado at 12:09 PM on 2 November 2007Mt. Kilimanjaro's ice loss is due to land use
Okay thanks. Some more relevant links: 1) Alps Glaciers Gone by 2050, National Geographic News. 2) Mountain Glaciers Melting Faster Than Ever, National Geographic News, which includes the following:Lonnie Thompson, an expert in ancient climates at Ohio State University ... said ... "Kilimanjaro's glaciers are melting so quickly ... that the mountain lost nearly a quarter of its ice from 2000 to 2006 ... [it points out that melting is accelarating everywhere and adds] ... If you look at what's happened to these glaciers, they're not just retreating, they're accelerating [their retreat]," he said. "And it raises the question of whether this might be a fingerprint of [human-caused global] warming.
In other words, even if the melting of Kilimanjaro prior to 2000 contains 0% influence from climate change (which is unlikely), the influence of climate change on the melt rate of Kilimanjaro since 2000 is almost certainly well above 0%. No other factor, including deforestation, can credibly account for the sudden acceleration post-2000. 3) Himalayan glaciers 'melting fast', BBC:"Melting glaciers in the Himalayas could lead to water shortages for hundreds of millions of people"
Admittedly this article has the disadvantage that it quotes a WWF study - it would be nice to find a similar one that was independent of any lobby group. But it's mainstream stuff and worth quoting if you can't find a better one on the Himalayas' glacier melt and the likely effect of this on neighbouring countries. 4) China glaciers melting at alarming rate, Chinese National Coordination Committee on Climate Change. -
Dave Rado at 09:14 AM on 1 November 2007Mt. Kilimanjaro's ice loss is due to land use
To say that climate change is definitely not even partially responsible for the loss of glacier ice mass on Kilimanjaro is an inaccurate misrepresentation of the science. As Raymond Pierrehumbert's article that you linked to made clear, it is likely to be at least partially responsible. Furthermore, Gore did not "get it wrong" as you claim - in the movie, the retreat of Kilimanjaro is not claimed to be purely due to global warming , but it is given as an example of the sort of thing one can expect in a warmer world, and it is quite true that loss of major glaciers is something we can expect. I also think you ought to link to the global glacier mass balance graph at on the National Snow and Ice Data Center (NDIS) graph here, from which one can see that the worldwide trend is sharply downwards; and there is no dispute in the peer reviewed literature that this is mostly due to climate change. Admittedly, Gore could and should have chosen a better example than Kilimanjaro, such as the Andean glaciers, but he didn't "get it wrong", he just illustrated a valid and accurate point with a poorly-chosen illustration. Finally, I think you should point out that hundreds of millions of people (and huge ecosystems) rely for their water on the annual glacier summer melts that in many cases may cease during the next 50-100 years, as mountain glaciers start to disappear. This includes a large proportion of China's population, all of the “Stans” (Pakistan, Uzbekistan, Turkmenistan, etc.) and most of the Andean countries in South America (e.g. see here , here and here).Response: Dave, all good points and I confess updating the Mt Kiliminjaro page is high up on my to-do list. Thanks for the link suggestions (I do link to the NSIDC graph elsewhere but here is a good place also) - will attend to this shortly as soon as time permits. -
John Cross at 22:28 PM on 29 October 2007We're heading into an ice age
Hi John: Thanks for the thanks (although I will hasten to point out that all I did was offer some minor comments). I am especially delighted to me mentioned in the same acknowledgement as Dr. Solanki. I don't know if Dr. Solanki reads this blog, but if he does I would like to say that I have been reading his papers since I came across the Harold Jefferys Lecture that he did about 4 years ago. Very interesting work! Regards, John
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