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RSVP at 05:51 AM on 4 August 2010Waste heat vs greenhouse warming
KR #173 I read what you wrote. I agree with everthing you say. However when you talk generally about waste heat, I am not sure where this is coming from specifically. My thought is that N2 and O2 are heated (atmospheric waste heat), or water supply (thermal water pollution). The N2 and O2 (i.e. non-GHGs that make up 97% of air) can either convect to the land, water or ice, or loose their heat via thermo-vibrational translation to GHGs, which in turn emit this energy via IR. In this case, GHG help remove waste heat, but this is not the typical channel (surface to GHG) that is normally modeled. -
Sheila at 05:43 AM on 4 August 201010 Indicators of a Human Fingerprint on Climate Change
@Bern I live near a major astronomical observatory, on La Palma, in the Canary Islands. I asked the head of one of the solar telescopes here (the Dutch Open Telescope http://en.wikipedia.org/wiki/Dutch_Open_Telescope) for his opinion on global warming. He said that he's not qualified to say what's causing it, but it's certainly not the sun. The sun has been unusually cool for the last 50 years or so. He must know what he's talking about. -
Albatross at 05:39 AM on 4 August 2010Why I care about climate change
Dappledwater @70, You may be right. Either way, the citing that graph as evidence as BP is, IMHO, very misleading. -
Rob Painting at 05:36 AM on 4 August 2010Why I care about climate change
Albatross @ 66 - in the absence of any kind of analysis of the winter deaths, and I can't be bothered researching it myself, I'd have thought the spike in deaths would mainly be due to cold and flu viruses being more prevalent in winter. That's the case down here in the Southern Hemisphere anyway. -
RSVP at 05:35 AM on 4 August 2010Why I care about climate change
dcwarrior #64 If anyone is in a position to retool (materially), it is the rich. -
Albatross at 05:29 AM on 4 August 2010Why I care about climate change
Thanks CBDunkerson @67. Wow, that is some time ago.... I see that my final hyperlink @ 66 did not work. Here it is -
Doug Bostrom at 05:26 AM on 4 August 2010Has Global Warming Stopped?
Just as a general remark Doug Proctor, the instant you mention Al Gore in an argument you distract your audience by introducing political content having nothing to do with science. More, if you're concerned with making a scientific argument your speech loses credibility because many people reading your words will realize you're bringing an ideological slant to your treatment. ...the predictions of disaster are modelled on a) the temperature data is 95% accurate, 2) no other significant "natural" temperature forcing mechanisms are working today, and 3) that human usage of fossil fuels will increase throughout this century as it did in the last part of the previous century. All apparently true so far, with the caveat that even if we were somehow to stop using fossil fuels today we'd see significant warming for a long time to come. -
Doug Bostrom at 05:00 AM on 4 August 2010Grappling With Change: London and the River Thames
Oops, forgot Michael Sweet! I don't know specifically about New Orleans or Miami. While digging for material for this piece I did run into planning materials for other places and I'll say my impression is that the British are exceedingly competent at pulling together vast amounts of information and synthesizing it into documentation suggesting coherent plans of action, probably close the best-case example. Their competence in this regard is actually rather staggering. Cameron should think twice about blowing up such a structure, shouldn't carelessly carve into the civil service there. What I can say regarding such places as Miami and New Orleans is that here in the U.S. the curious asymmetry between local and national governmental units is also visible. Where I live the department of transportation is taking into account sea level change when planning major roadway improvements, for instance, while meanwhile the farther up we go in government the more vague and amorphous the response. But I don't see the same scope of coherence and involvement visible in the U.K. My intuition suggests that Miami and New Orleans will suffer "death by a thousand cuts" if sea level goes the way it seems to be headed. The process already seems to have started in New Orleans though of course Katrina was not necessarily an outcome of climate change-- a city partially below sea level in an area affected by hurricanes is a dubious proposition at best. New Orleans has suffered what appears to be a permanent population loss, another storm will of course inevitably mess with New Orleans and it's not hard to picture more people giving up. Rinse and repeat. Enough population loss and eventually it'll lose the political clout to attract federal dollars for protection. -
Doug Proctor at 04:57 AM on 4 August 2010Has Global Warming Stopped?
That the Earth is warming is neither here nor there when it comes to AGW-CO2 discussions. The point in all this debate is whether the warming is man-made and man-controllable vis-a-vis CO2 reductions from fossil fuel usage. The input of CO2 is not considered a factor in temperature rises by warmists or skeptics until the period of 1965 or 1975. Graphs showing warming prior to this period show "natural" warming ASSUMED to have stopped to any significant level in the '65/'75 times. This is certainly an assumption without evidence, for the inclusion of some pre-CO2 impact warming is to reduce the effect of fossil fuel CO2 currently and to take away some of the "catastrophic" temperature rise. It would also serve to kill the more outlandish of the IPCC temperature rise modelling efforts. "Warming" per se is not the issue. Is the warming since the '60s following the IPCC CO2 models? Is the temperature data we are using corrected properly? The adjustments are a significant portion of the "anomalies". We are alarmed by a very small difference in the day-to-night, summer-to-winter variation, after all, and must have exceptionally good data to have confidence that what is purported is good. The confidence level of the IPCC reports is about the mathematics used to identify the change in the data involved, NOT the quality of the data being used. A 95% confidence in a 0.7C* change since 1960 is misleading when data adjustments during that time period amounts to 0.4C*: if an incorrrectly applied UHIE has biased the temperature readings upward by 0.15*C, then what does a 95% certainty mean? A temperature rise of 0.55C* (taking but one non-CO2 effect into account) devastates the AGW argument, as the catastrophe either no longer exists or is one to require us to burn INCREASING amounts of oil and gas for 300 years. Remember that the IPCC and Gore disaster is based on an expanding human population and industrialization that will rocket our use of fossil fuel even while those resources are limited and, as many think, past their peak. We lose track of the argument that it is only the post 1960s warming we are to associate with CO2, and that the predictions of disaster are modelled on a) the temperature data is 95% accurate, 2) no other significant "natural" temperature forcing mechanisms are working today, and 3) that human usage of fossil fuels will increase throughout this century as it did in the last part of the previous century. I suggest that each of these assumptions is questionable, and together they make the "death spiral" of the Earth a proposal more to help Mr. Gore buy more seaside mansions than to make Mrs. Gore buy an electric car. -
Has Global Warming Stopped?
robhon #7, tobyjoyce #38 - For myself, I've always phrased it as "Hindsight consists of looking at an ass"... -
tobyjoyce at 04:42 AM on 4 August 2010Has Global Warming Stopped?
robhon #7, The French have a word for it: l'esprit de l'escalier, roughly "the wisdom of the staircase". It is the hindsight we have on the way back down the stairs i.e. too late. Or, as someone misquoted Robbie Burns: The best said words of mice and men Are those we did not think of then -
CBDunkerson at 04:40 AM on 4 August 2010Why I care about climate change
Albatross #66 wrote: "When did we last have a record cold year (or month) globally?" According to GISS the years 1890, 1907, and 1917 are tied for the lowest global temperate anomaly at -0.39 C. The global monthly lows are; Jan: -0.82 C in 1893 Feb: -0.58 C in 1893 Mar: -0.49 C in 1911 Apr: -0.48 C in 1911 May: -0.55 C in 1917 Jun: -0.43 C in 1907 Jul: -0.39 C in 1912 Aug: -0.52 C in 1912 Sep: -0.45 C in 1912 Oct: -0.52 C in 1912 Nov: -0.51 C in 1890 Dec: -0.69 C in 1917 So the most recent global record lows (for May, December, and the entire year) were in 1917. Not quite a century ago. -
nhthinker at 04:27 AM on 4 August 2010On Consensus
As an engineer, I understand all about noise. Noise can be averaged out if what is being looked for is long term trends. If the noise can not be averaged out for the time frames you are concerned with, then you can't make supportable claims about the accuracy of the underlying signal. Best judgement in the 70s was CO2 doubling would be 2 to 4 degree C change. It was also contemplated that the Earth's response to elevated CO2 would be linear or that it might trigger some damping response or multiplying effect within the complex interworkings of atmosphere clouds and oceans in addition to the nonlinear effect in the polar regions. How much have those numbers "tightened up" in the last 45 years? Maybe not at all. How much have we learned about the other effect of increase CO2 or increased temperature as to whether their exists the probably of additional damping or mulitplying effects of sustained higher temperature? Not much, because the changes to the environment (our experiment) is so slow. Repeatability is critical to good scientific confidence. That is what it takes to be a hard science. Climate science is no where near established enough to make repeatable hundred year predictions. I find it humorous that those advocates here will not concede that sciences that involve controlled repeatable tests and relatively short time scales are inherently more reliable than sciences that only involve one object under test and the scientists are too impatient to propose a model and then wait until it is proved out by the data and instead constantly tweak the model much faster than the experiment actually runs. Medical science involves plenty of different independent objects to test and time scales where the scientific impatience does not play as large of role. Is there anyone on this forum that claims to be a climate scientist and would also claim that Climate science rivals medical science in term of its certainty of its hypothesized models tested by repeatable trials by independent scientists? The answer is no scientist worth his salt would ever make such a claim. They might claim climate science certainty is good enough, but it is no where in the same league as medical sciences or physics. The people on this board seem to have forgotten some fundamental principles of science. Those that separate the hard sciences from the softer sciences. There are still huge things to discover about climate science. I totally agree with -
Doug Bostrom at 04:20 AM on 4 August 2010Grappling With Change: London and the River Thames
Thank you JMurphy, I'll take care of that. Chris, glad you enjoyed it; part of my thinking in doing this was that we talk a lot of abstractions but there is a continuum between the concepts and concrete. Indeed London is sitting on a bed of slowly-compacting clay, present iteration of the Thames Barrier included this as a factor. More information on the general situation coming up in my response to GC. With the price of real Reggiano parmesan what it is these days, I think I may keep a shovel handy near the refrigerator, just in case. Believe it or not actually thoughtfull I ended up slicing away several hundred words from this thing, it reminded me of the apocryphal Chinese Boeing 707 copy that was too heavy to take off. Yet I found that like an airplane it needed wings, fuselage, tail and engines to work the way I planned. It definitely won't be to everybody's taste, heh! Indeed the whole southern coast of England is sinking dorlomin. The rate varies by location; near London it's dropping at a pretty good clip of 0.5mm/yr. Thank you for the complement, GC. This was fun to write because it was less about direct hectoring with scientific facts, more a casserole. That's really interesting what you say about pumping the aquifer. If you dig into the raft of documents concerning the general hydrological background of London it turns out that they're now doing a bit of a balancing act. Removing -too little- groundwater means they begin to have groundwater flooding problems, -too much- and the subsidence becomes a bigger issue. Reminds me of when I lived in Atlanta Georgia and ignorantly placed a dehumidifier in the basement of my home which was sitting on a shallow foundation on red clay. I think you can picture the result! I had to establish a compromise between mildew and throwing of doors, floors etc. -
Albatross at 04:14 AM on 4 August 2010Why I care about climate change
BP @58, Is this really the post where you choose to argue? I would prefer not to, but you make some pretty misleading comments in your post that cannot go unchallenged. Of course it gets hot almost every spring in south Asia before the Monsoon starts. No-one here, incl. John, is to my knowledge disputing that fact. What we are talking about are extreme heat records being broken. And yes, cold can kill too....got it. As for your misleading British graphic, you are assuming that b/c it is for winter that all those deaths are attributed to the cold, but that is not true. They say: “During the winter months, mortality in England and Wales reaches higher levels than during the summer months. A measure of this increase is provided, on an annual basis, in the form of the excess winter mortality figure. This figure is a simple way to assess mortality levels over the winter as a whole. Excess winter mortality is calculated as winter deaths (deaths occurring in December to March) minus the average of non-winter deaths (April to July of the current year and August to November of the previous year).” So those deaths are on account of a multitude of factors, and are not all attributed to deaths because of unusually cold temperatures. Now, the UK Met office does clarify and states that “In the UK there are, on average, 25,000 extra deaths in winter compared to other months of the year — 80% are thought to be due to the cold”. Hardly a clear or quantitative picture. Interestingly, in the USA (between 2000 and 2009) average annual deaths from heat (162) far outnumber those from cold (21), as do deaths from flooding (65).
So it seems that people in the UK are not well equipped or educated on how to deal with unusually cold weather. So you citing the UK data (which is misleading) looks like an example of cherry-picked to me.
Anyhow, the warmth being experienced now is on a global scale, as suggested by the satellite, radiosonde and surface data. According to the RSS MSU data, July 2010 is now the warmest for July on the satellite record. When did we last have a record cold year (or month) globally?, or when was the last year when the global mean temperature was below the long-term mean? According to NASA GISS, the answer to the latter is 1976—34 years ago.
Not surprisingly, 2010 is currently tied with 2007 for the number of national all-time (i.e., on record) highs for nations around the globe:
National all-time record high temperatures around the globe in 2010 (including Pakistan which you seem to object to) = 15.
National all-time record low temperatures around the globe in 2010 = 1.
In 2003 there were twelve and in 2003 eleven and in 1998 nine, all-time record highs. For more go
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Doug Bostrom at 03:57 AM on 4 August 2010Visually depicting the disconnect between climate scientists, media and the public
Stylo you're not producing a useful critique. From your remarks it's pretty clear you don't know about survey methodology, you're instead wading into another area of expertise you're missing and pronouncing unfounded judgments. This is a really conspicuous pattern among contrarians. Airily dismissing multiple scientific disciplines to harbor a cherished belief is not a viable argument. -
Chris G at 03:45 AM on 4 August 2010Why I care about climate change
Not much new to add here, but I'll take the opportunity to wax philosophically, and I have a few thoughts: I liked the analogy of balanced weights and adding just a little bit to one side. When we are talking about climate science and climate change, we are not talking about forces that have not existed before; we're just debating effects of changing the balance point. RSVP, John explicitly said the cartoon did not apply; though, even as I write this I find myself drawn into that trap. More energy in the earth system shifts the distribution of rain, regions than were marginally sustainable agriculturally become unsustainable. Regions that had been unsustainable may become so, but there are no farmers living there and the transition will not be without hardship. Think of the effects on crops and people when the temperature reaches the hottest week of the year. Now expand that time out to either side by 2-4 C and raise the temperature in the middle time by the same amount. In case you don't know anything about agriculture, that is really bad for yields. Wheat prices are higher globally now and that could be a result of the heat waves in the Moscow region. Fortunately, the US has had a really good year for wheat. What happens if/when the weather dice become loaded to the point when it is not uncommon for them to give us a bad year in both or more regions? I'm puzzled why there is controversy between religion and science. Surely there is more to this universe than we understand, and likely may be capable of understanding. Stimulate a neuron and it fires more. There doesn't appear to be much cognition or awareness there; so, how do you tie a whole bunch of non-aware neurons together and end up with "I think; therefore, I am."? There are modern models of reality that require somewhere between 6 and 11 dimensions to work; I have some doubt that the human brain is capable of conceptualizing 11 orthogonal dimensions. Symbol manipulation - sure, even I can do that, but actually conceptualizing them all at the same time; I doubt it. Just a couple of illustrations that leave a lot of room for there to exist things we really don't understand, physical and metaphysical, and may even make the boundary a little fuzzy. When I was in 7th grade my science class grew bacteria in a petri dish. We watched as our colonies grew from tiny specs to flourishing, multi-colored conglomerates. But, then the population appeared to enter an unhealthy phase and eventually decay set in and a wasteland was created. I was saddened when my colony collapsed; either the microbes had made their environment toxic through their own waste or they had consumed all the available resources. I thought, if only they had regulated themselves, they could have sustained their glory days indefinitely. Then it occurred to me that biological organisms without thought are only regulated by predation. The end result of no regulation is always bloom and collapse. This was quickly followed by the recognition that humans have no predation; in remains to be seen if, as a species, we have more thought than a microbe. -
dcwarrior at 03:37 AM on 4 August 2010Why I care about climate change
#63 John Russell - I am sure you are right. Speculation - when global warming is discussed, what are the things that have to be done about it? 1. Your car is bad. People LOVE their cars. They wrap their identity in their cars. They like big cars that go fast. 2. The suburban lifestyle is bad. I.e., the very yardstick for measuring the American dream. The way we hope to advance in society, to show we are better than the Joneses - that's bad? 3. Consumption is bad. I.e., another yardstick of the American dream. There may be others. But we are telling people they have to give up that upon which they have built their hopes and dreams. AND, if they should take the scientists' advice, they'd fall behind. What if the scientists are then wrong? I can imagine how such an anxiety would make people vulnerable to someone stating emphatically that the scientists are wrong, there's nothing wrong with CO2 and all the worry is a product of deluded liberals who are out to get research money. -
chris at 03:31 AM on 4 August 2010Plant stomata show higher and more variable CO2 levels
David Middleton at 02:06 AM on 4 August 2010 Geocarb: The most up to date versions of Berner’s excellent model for long term carbon cycle processes [***] have a temporal resolution of 1 million years. Geocarb is a model. It isn’t a measure of [CO2] in the deep past, and it certainly can’t be used to assess [CO2] during the Neogene ice age cycles represented in Antarctic cores (see following paragraph). In any scientific analysis we use the appropriate tools. Geocarb, however nice a model, doesn’t give us insight into atmospheric [CO2] during the last 700,000-odd years where we have highish resolution direct measures of atmospheric [CO2] from ice cores. I wonder whether you have read the Geocarb papers? These show zero variation of [CO2] during the Neogene ice age cycles. If you look at the Geocarb papers you will see that the [CO2] levels in the deep past (Phanerozoic) are defined as “RCO2 is the ratio of the mass of atmospheric CO2 at a past time to that at present (weighted mean for the past million years”) (see e.g. legend to Figure 18 of the linked paper). David, if Geocarb sets the baseline for atmospheric [CO2] by averaging the last million years, how can we possibly use Geocarb to assess specific atmospheric [CO2] in ice cores?Your argument simply doesn’t make sense. Geocarb is a model for assessing our ability to constrain [CO2] levels in the deep past through our understanding of long term (multi-million year) carbon cycling. Please read the paper(s). Plant stomata: ”Plant stomata are a lot noisier than ice cores. One doesn't just throw out the high frequency data in signal processing just because it's noisy.” The problem is that the noise (+/- 30-60 ppm as indicated in the paper I linked to in my post you’re responding to) often overlaps with the difference between ice core [CO2] data and apparent stomatal [CO2] data. It’s not a question of “throw(ing) out high frequency data”. The question is whether the apparent differences between some (but not all) stomatal data and ice core data is statistically significant. I think we both agree that the ice core [CO2] data is temporally averaged due to the variably slow rates of firn sealing. However there isn’t any strong evidence that the ice core data is biased low as you insinuate. If the stomatal frequency boffins come at some point to a conclusion as to a reliable means of determining historic [CO2] with highish precision, then that will be great. In any case the high resolution Law Dome data is only temporally averaged on the decadal time scale. AIRS and polar [CO2]: We're quibbling (or you are I should say!) over a few ppm of [CO2]. You're happy to use a model for [CO2] in which [CO2] is averaged over the last 1 million years to attempt to counter the Antarctica ice core data, and yet you are fussing about a possible few ppm difference between Antarctic [CO2] and global [CO2]. I think your quibbling is misplaced. Atmospheric [CO2] has been measured in Antarctica (South Pole) since the early 1990's. We can compare the directly measured South Pole [CO2] with the [CO2] measured at Mauna Loa or from the globally averaged sea surface sites (or with globally and yearly averaged AIRS data). The difference is small (a few ppm). How science works: The idea that scientists set out to "debunk" something is silly. Scientists set out to find stuff out. With careful experiment and analysis the real world leads them towards reliable interpretations of natural phenomena. If this happens to lead to a robust conclusion that is at odds with other interpretations then that's just great. I can't imagine a real world example where your assertion "Science is all about skepticism and debunking (AKA testing)." might have any meaning! Science is surely about the formulation of hypotheses, testing these with experiments/analyses and seeing where the latter lead. [***] Berner RA (2006) GEOCARBSULF: A combined model for Phanerozoic atmospheric O-2 and CO2 Geochim. Cosmochim. Acta 705653-5664. -
gallopingcamel at 03:25 AM on 4 August 2010Grappling With Change: London and the River Thames
doug_bostrom, Thanks for a terrific account. It was of special interest to me as I used to work in Greenwich where the S.S. Mackay (a venerable cable ship) was moored. The roads inside our factory were far below high tide so the Mackay seemed to float above us. While I had nothing to with flood control on the Thames I worked hard to clean up the river so that fish could return. By 1979 I was raising rainbow trout in commercial quantities using Thames water. This was only possible because the water quality was steadily improving thanks to a collaboration between industry and volunteers coordinated by government (the Thames Water Authority). In Pepys' day, the Thames was a commercial salmon river but the water quality deteriorated as the city grew. The last Thames salmon was caught in 1815 but now the salmon are back, showing that even catastrophic levels of pollution can be reversed. Like Mexico City, much of London is sitting on hundreds of feet of mud. There is also an excellent aquifer and my company had a 500 gallon/minute well. After a little arm twisting by the TWA we stopped pumping. We were told that the depletion of the aquifer was causing London to sink. Is that effect measurable? -
John Russell at 03:13 AM on 4 August 2010Why I care about climate change
In spite of what the deniers would like the general public to think, concern for the effects of AGW seems not to be linked to religious, political, monetary or other influence or belief. I know sceptics, deniers and 'warmists' (ugly word -- but short) from the both the left and right, religious and otherwise. I'll accept that there is perhaps a tendency for environmentalists to be concerned about AGW, but that's hardly surprising is it? And anyway, what's to be despised about concern for the environment? I suggest that what divides the two sides is more likely to be something psychological; something perhaps related to fear. One of these days some scientist will work it out. In the meantime, John, keep up the good work. It's very much appreciated. -
OntheEdge at 03:03 AM on 4 August 2010Why I care about climate change
[first time user -apologies if this is a double post] just wanted to add my thanks for this well informed site which I've used in my battles with deniers within the community of believing Christians. Quoting the prophet Amos is so apt as he faced the same sort of denial of responsibility in his time as we see and hear today among right wing Christians. Believing themselves to be chosen and special while adopting alien ideologies which excused their lack of concern for the poor, Amos rightly tore into them no holds barred. -
RSVP at 02:14 AM on 4 August 2010Why I care about climate change
John, Your website (and motive) is commendable, and I am grateful to you. The cartoon above is perfect! Commenting... under Soviet domination, countries in Eastern Europe relied more on public transportaion and used horses for farming in great numbers before the fall of the Berlin Wall. They didnt realize that they were ahead of the times with their "backward" psuedo-ecological farming methods. The same may apply still in parts of India, etc., but things are changing fast, unfortunately... or?? Economic growth is tied to method, and method obviously makes a difference for global warming. For now, reducing poverty appears to be at odds with global warming. (Try to imagine getting emergency food supplies today in Africa without fossil fuels.) The problem is not simple, and regardless of whether global warming it is due to GHG emissions, waste heat, or something else, the expectations for sustained economic expansion remains and needs to be seriously addressed. (Greener, slower lifestyle issues might be a good future topic... or how much is too much???) And can this be discussed without getting political? -
Waste heat vs greenhouse warming
RSVP - In reference to my previous post, noting that if GHG's increase -> outgoing radiation decreases -> there is an energy imbalance -> the energy/temperature of the Earth/atmosphere will accumulate/increase until energy in = energy out.: The Empirical evidence topic, Figure 2, directly shows the effect of GHS's on the efficiency of the Earth radiating energy to space. This is the energy imbalance I referred to, and leads to energy accumulating until the temperature rises and the sum energy radiated out equals that coming in. -
David Middleton at 02:06 AM on 4 August 2010Plant stomata show higher and more variable CO2 levels
chris at 08:28 AM on 1 August, 2010David Middleton at 07:00 AM on 1 August, 2010 GeoCarb is a (very nice) model with 10 million year resolution. I don't see how you can use this to say that much about what true [CO2] levels were in the past at high resolution. It certainly doesn't "trump" direct measurements.
The Antarctic ice cores are not "direct measurements" of global atmospheric CO2. They are direct measurements of gas that filtered into snow and were eventually trapped in ice. They are an indication of what the atmospheric CO2 was in the air, near the ground over Antarctica.
GeoCarb is a very low frequency model-derived function. The resolution is low; but it is far better than 10 million years in the Neogene.
It shouldn't "trump" the ice cores. But it should be incorporated with the ice cores and the stomata data to a more complete "spectrum" of the CO2 "signal."
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Waste heat vs greenhouse warming
RSVP - "Now you are basically saying that GHGs are removing waste heat. In other words, CO2 is helping to cool the atmosphere." I'm wondering if you are deliberately being obtuse? I'm really having trouble understanding your comments in any other context. "...it has to radiate both sources of energy into space." - If the Earth is in energy equilibrium (averaging over a period of time, it never is on an instantaneous level), it needs to radiate as much energy out to space as it receives from the sun, radioactive decay at the core, AHF, and whatever hot air is generated by climate discussions. Equilibrium means energy in = energy out. The amount of IR radiation emitted from the Earth and the atmosphere scales with the 4th power of temperature. So if there is an increase/decrease of energy going in -> the temperature will rise/fall until the radiation out equals that amount of energy. In addition, GHG's slow the radiation of energy from the Earth and atmosphere (the Earth becomes less efficient at radiating energy at any particular temperature), which means that if GHG's increase -> outgoing radiation decreases -> there is an energy imbalance -> the energy/temperature of the Earth/atmosphere will accumulate/increase until energy in = energy out. -
CBW at 02:00 AM on 4 August 2010Why I care about climate change
John, Probably unnecessary, but I'll add my thanks for your efforts on this site. You're doing important work, and making a difference in the world. I hope your daughter comes to admire that and learns from the example you set. -
Rob Honeycutt at 01:55 AM on 4 August 2010Visually depicting the disconnect between climate scientists, media and the public
Stylo @ #82... I would also suggest you spend some time looking at how polls are crafted and executed. When Gallup does a phone poll they get a small response rate relative to the number of calls they make. Those individuals who agree to take the poll are "self selecting" on a voluntary basis. Not a random sample. From there the responses are broken down into smaller constituent parts. Go look at some of the polling agencies out there. Usually polls consist of between 500 to 2000 responses. That is what determines the margin of error for the polls. Doran 2009 is well within a normal response rate and a normal margin of error for a quality poll. As we've look at this issue from many sides we keep coming up on similar figures. Doran comes up with 97%. Anderegg comes up with the same number. And even in our conversations with Poptech here, we're coming up with potentially a similar ratio of papers. As I see it, we're building multiple lines of evidence that are pointing to the same answer. -
Albatross at 01:54 AM on 4 August 2010Has Global Warming Stopped?
Re #27 and #32, I humble request to please do the same here, a certain poster's privileges, as has been done elsewhere. -
Albatross at 01:49 AM on 4 August 2010Why I care about climate change
Dear John, Thank you for sharing. Thank you too for standing up for science and what is right. -
Rob Honeycutt at 01:42 AM on 4 August 2010Visually depicting the disconnect between climate scientists, media and the public
Stylo... Regarding consensus on quality in art. I would highly suggest that you take a course or two in art history. You may have subjective opinions about different styles or pieces of art, but the art world overall is very consistent and objective about what constitutes quality. But the broader point here is that quality is not a subjective matter. If you have a product that is a piece of crap you are highly unlikely to have two people look at it and get two subjective opinions on whether it is of good or poor quality. -
dorlomin at 01:15 AM on 4 August 2010Grappling With Change: London and the River Thames
The whole south of England is offcourse sinking and much of it vaulrable to to flooding due to its flatness. By chance a couple of weeks ago I had a cycle excursion to Dunwich which is the most famous lost town in the region, coastal errosion and sinking land has seen what was once a prosperous town now the better part of a mile out too sea, only a vilage remains with the name. I am not sure of the rate of sinking but I dont think it is significant over just one century. -
actually thoughtful at 01:10 AM on 4 August 2010Grappling With Change: London and the River Thames
Doug, with great respect, you talk to much! How about posting twice as often with shorter posts?! I got about halfway through when I hit overwhelm. I will try to finish later. I note you have a technical article about sea level/storm surge/spring storms, and later on I find your consistency of public opinion graph, which suggest (I admit I haven't yet read the whole thing) a way to break the article into the technical problem and the political problem. Offered for your consideration, and not as a snipe. Tom -
Berényi Péter at 01:05 AM on 4 August 2010Why I care about climate change
#57 chris at 00:42 AM on 4 August, 2010 It's a fact of life that people die (especially the elderly and infirm) and another fact of life that (in the UK) deaths are more numerous in the winter It's also a fact of life it can get hot in Pakistan and India. So what? And yes, excess winter deaths occur because of the cold, poverty and poor housing. J Epidemiol Community Health 2003;57:784–789 Excess winter mortality in Europe: a cross country analysis identifying key risk factors J D Healy -
RSVP at 00:53 AM on 4 August 2010Waste heat vs greenhouse warming
KR #169 "...it has to radiate both sources of energy into space." Now you are basically saying that GHGs are removing waste heat. In other words, CO2 is helping to cool the atmosphere. doug_bostrom #170 I was referring to the numbers, not the theory. Until a theory is disproven, and it is the best thing that you have, then there is nothing wrong with acting on it. This however does not make the theory exempt from examination, and the journey is always a good thing. -
michael sweet at 00:53 AM on 4 August 2010Grappling With Change: London and the River Thames
Doug, Excellent post with lots of good references. Has the planning in New Orleans considered sea level rise seriously yet? Is Miami starting to plan for sea level rise (how could you start to defend Miami?)? How much difference is there between the planning from different countries? Can anyone suggest links to planning documents? I have seen reports that Holland is already seriously planning for sea level rise, of course they have more experience than most countries. -
chris at 00:42 AM on 4 August 2010Why I care about climate change
Berényi Péter at 00:24 AM on 4 August, 2010 That's a little illogical Peter. Unanticipated extreme events for which societies are unprepared result in excess deaths. Occasionally these are heat-related (e.g. the Pakistan/India heat waves or the heatwave in Europe in 2003 etc.). In a warming world we expect these latter events to increase. Your graphic shows the normal background excess of winter deaths in the UK. It's a fact of life that people die (especially the elderly and infirm) and another fact of life that (in the UK) deaths are more numerous in the winter. Note that this is a little anomalous since winters in the UK are not that cold. Unlike countries with very severe winters (where anti-intuitively perhaps, there are fewer excess winter deaths), elderly people in countries with mild winters are more likely to allow themselves to be taken unawares by the effects of cold.. -
Stephen Baines at 00:37 AM on 4 August 2010Why I care about climate change
Werecow In what way have you felt bamboozled by climate science? Interesting BP...but I imagine its not necessarily the cold that leads to higher winter mortality rates. Darkness must play a role in automotive related mortalities, for instance. What were the sources of mortality behind those excess rates? It not immediately clear from the link. -
Berényi Péter at 00:24 AM on 4 August 2010Why I care about climate change
John Cook wrote at 08:49 AM: Thousands died in record heat waves in Pakistan and India in recent months And tens of thousands in England because of the cold, each winter. Have a look at the Excess Winter Mortality page of the UK Office for National Statistics, please.
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Dikran Marsupial at 00:11 AM on 4 August 2010On Consensus
Re: nhthinker Loth as I am to do so, I am forced to point out that nnthinker is engaging a rhetorical, rather than scientific argument, in which I am not that keen on participating. DC is right, scientists do need to know about rhetoric; IMHO it needs pointing it out, but it is best just to stick to the science otherwise and not be drawn into the same tactics (I hope I have managed that here). For example, asking for an example of an accurate climate prediction "What is your iconic climate model prediction that has proven accurate by the test of time?" and then when some examples are given, replying "The advocates here seem to fall into the fortune teller's trap. There will always be some accurate prediction of of future events, especially when you have thousands of predictions to choose from. Which rather transparently shows that there was little genuine interest in the answers. There is certainly an element of "having your cake and eating it as well". There is also the point that I have explained more than once that "90% correct is a meaningless term, and nhthinker is still using that term and has not attempted to engage in the point that the internal variability of the climate means that the accuracy of a prediction is not so easily measured as that phrase suggest. The quote from Gavin Schmidt is rather curious, in that in a couple of occasions it mentioned the internal variability ("weather noise") that I raised, here "The implication is that over a short period, the weather noise can mask significant differences in the forced component." and here "Given the noise level, a trend 75% as large, would still be within the error bars of the observation (i.e. 0.18+/-0.05), assuming the transient trend would scale linearly" In other words, the weather noise in the data is large enough over such a period that the model could be very different and still be consistent with the observasions (note it is the error bars of the obervaions he mentions, not of the models). The highlighted bit "Is this 20 year trend sufficient to determine whether the model sensitivity was too high? No." Doesn't say that the model is wrong, just that there isn't enough data to be confident of detecting an error (as the "weather noise" is too large). Which was pretty much what I was trying to explain. Regarding "Broeker's analysis was directionally correct.", that is a little disingenuous as he predicted global warming of 0.8 degrees over the 20th century, and the GISS data show a warming of about 0.82 (judging from the plot). I'd say that was rather more than merely "directionally correct".
If you want to know Gavin Schmidt's views, why not ask him? If you don't want to email him, you could always post a comment on RC marked "FAO Gavin Schmidt".
That will be my last response to nhthinker (chorus: phew! ;o) until he actually engages with the point that "weather noise" means that it is not possible to achieve an arbitrary level of accuracy, even if your model is perfect.
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werecow at 23:48 PM on 3 August 2010Why I care about climate change
I'm not a big environmentalist either, but I do take an interest and I have my share of concerns. That said, for me the reason for getting into this is mostly just my general interest in science, with a particular interest in topics where there are public controversies that don't reflect the state of science. In other words, I love learning new things and enjoy applying my skepticism. It's addictive. I've moved around between different topics in skepticism and my main focus until recently had been on evolution theory, but climate change is an especially interesting case because it's one where you really do have to engage with the material to see through the more sophisticated arguments. It highlights a general problem in skepticism, that it's not always clear to a layman where to draw the line between genuine skepticism and contrarianism. And the debate is so highly politicized that you don't always know who to believe, or whether you can believe anyone at all. But figuring out things like that is what skeptics do best, after all. Plus, as I started reading up on the material, I realized I had been mislead about both the reality and the potential severity of the problem myself. I have to admit, that kinda pissed me off. I don't like being bamboozled, so now I'm trying to learn as much as I can, get a solid foundation, and perhaps push back just a little bit when appropriate. I'm still trying to determine where exactly that line should be drawn, but I'm learning a lot of interesting things about climate science, so at least I'm enjoying myself. -
CBDunkerson at 23:40 PM on 3 August 2010Why I care about climate change
Poptech #52 Seldom have so many laughable ironies been condensed into so few words. I salute you sir. -
chris1204 at 23:22 PM on 3 August 2010Grappling With Change: London and the River Thames
Britain's tides have a noble history - Julius Caesar's first invasion of Britain in 55 BCE was majorly disrupted because his navy could not cope with North Sea tides. Following up from HR's post, I note the link suggests subsidence may also be a problem as is often the case with 'reclaimed' lands. Reclaimed lands are especially vulnerable especially if there's extraction of artesian waters - eg, Venice or Mexico City (which is built on what was once a lake). Meanwhile, major parts of Scandinavia (eg, Norway) are still uplifting following the melting of the ice (while other areas such as Denmark conform more to the estuarine floodplain model). I guess it's all complicated and needs to be looked at on a case by case basis (which is not the same as complacency). However the whole AWG business plays itself out, our concern should be above all for the losers as opposed to a casual winners and losers shrug of the shoulders. I enjoyed this article which highlights in a concrete and immediate way important philosophical questions facing a city we take for granted. The historical backdrop makes it all the more fascinating. Hardly anyone today would think of burying their stock of cheese in the face of catastrophe - we take so much for granted these days in our relative prosperity. Pepys, what's more, was a wealthy man in an influential position. A bit off topic but Pepys' decision to bury his cheese brings to mind a story from my father's life. He managed to get away from what was then Soviet occupied Poland in 1940 to spend his adolescence in Greece under German occupation in a time of famine. His first suit cost three loaves of bread. He was lucky but he does look very skinny in photographs from that time. Similarly, my father in law spent his adolescence in Shanghai (having also managed to get away from Poland in 1939 ahead of the German army). His whole family (four adults plus an adolescent boy) occupied a single room in the Jewish ghetto in rather straitened circumstances. They still employed a Chinese maid. One can only imagine her poverty. It's a calculus difficult to imagine yet it formed part of the lives of real people who right up till 1939 also took their prosperity very much for granted. -
Arkadiusz Semczyszak at 23:03 PM on 3 August 2010The Past and Future of the Greenland Ice Sheet
@Chris - We refresh “a little bit” of literature - references: A. Regarding MIS 11: Sea level 400 000 years ago (MIS 11): analogue for present and future sealevel?,Bowen, 2010; and: Comment on D. Q. Bowen (2010); by Hearty, 2010. B. Most global causes of melting ice in Greenland: Millennial scale climatic variations and bipolar seesaw pattern, Capron et al., 2010: “NorthGRIP records enable us to depict the sub-millennial scale variability during the GIS of MIS 5 and thus, to highlight new type of features (GIS 21, 23) observed also during MIS 3 (GIS 11, 12, 13–14, 16). These new patterns appear as (i) precursor-type events prior to the onset of GIS (ii) rebound events at the end of GIS and (iii) centennial-scale cooling during the long and warm GIS 24. In addition to the internal forcing of ice-sheets on the climatic evolution during these events, we have proposed the external influence of the summertime insolation at 65 N. [!] Disentangling the main processes leading to these sub-millennial scale structures (ice-sheet, insolation, sea-ice, and hydrological cycle forcing) will require dedicated modelling studies. Through our results, we assume that orbital-scale variations play a role in rapid climate change but, also, the millennial-scale variability may hold clues to the long term climatic changes (i.e. Weirauch et al., 2008; Wolff et al., 2009b). Comparing Antarctic and Greenland behaviour over the succession of AIM/DO back to MIS 5 provides a more complete description of the bipolar seesaw pattern. As expect from the bipolar seesaw concept, a linear relationship between AIM amplitude and preceding GS duration only holds for shorter events, while for extraordinary long GS a new heat flux equilibrium between the Northern and Southern Hemisphere is obtained (EPICA c.m., 2006, Stocker and Johnsen, 2003) and the Southern Ocean warming ceases. The conceptual model of Stocker and Johnsen (2003) for a thermal bipolar seesaw is able to represent most of the variability of the north-south relationship depicted in Greenland and Antarctic isotopic records, even at sub-millennial timescale. However, it is not able to depict the delay of Antarctic warming after the beginning of the GS during the periods associated with large ice sheets (i.e. during MIS 2 and the end of MIS 4). It shows that Greenland ice core temperature proxy records cannot be taken as direct proxy for AMOC changes as suggested from the conceptual model. To go beyond our description and the conceptual model of Stocker and Johnsen (2003), the new types of DO events identified during MIS 5 should be studied with more complex models (e.g. Ganopolski and Rahmstorf, 2001; Knutti et al., 2004). This would allow quantification of the influence of insolation, ice-sheet volume, sea-ice and hydrological cycle on sub-millennial-scale variability (precursor and rebound events). This should provide also a better understanding of the response of Antarctica to these types of events.” Influence of solar variability, CO2 and orbital forcing between 1000 and 1850 AD in the IPSLCM4 model, Servonnat et al. 2010: “With a signal-noise ratio (SNR) estimate we found that the temperature signal of the forced simulation is significantly different from internal variability over area wider than ~5.106 km2, i.e. approximately the extent of Europe. ORBITAL FORCING PLAYS A SIGNIFICANT ROLE in latitudes higher than 65° N [! - Greenland !] in summer and supports the conclusions of a recent study on an Arctic temperature reconstruction over past two millennia. [...] The forced variability represents at least half of the temperature signal on only ~30% of the surface of the globe. This study suggests that regional reconstructions of the temperature between 1000 and 1850 AD are likely to show weak signatures of solar, CO2 and orbital forcings compared to INTERNAL VARIABILITY.” Extreme deepening of the Atlantic overturning circulation during deglaciation., Barker et al., 2010: “We conclude that the rise in atmospheric CO2 concentrations and resultant warming associated with an especially weak overturning circulation are sufficient to trigger a switch to a vigorous circulation, but a full transition to interglacial conditions requires additional forcing at AN ORBITAL SCALE.” “The fact that [AMOC] can react in such a way is really exciting.” A team of researchers, led by Dr Stephen Barker from Cardiff University, has investigated how changes in a key component of global ocean circulation are related to significant changes in temperature, which have taken place IN THE RELATIVELY RECENT GEOLOGICAL PAST.” “But the researchers believe the link between the AMOC and DEGLACIATIONS OVER THE LAST HALF A MILLION years is too strong to be a coincidence. It looks like deglaciation may only happen when the AMOC shifts from weak to strong.” “And these changes can have extreme effects. During the Bølling-Allerød (B–A) warm phase, 14,600 years ago, temperatures rose by 9 degrees Celsius over the course OF JUST A FEW DECADES.” Natural forcing of climate during the last millennium: fingerprint of solar variability, Swingedouw et al., 2010: “Then, we focus on the regional climatic fingerprint of solar forcing in winter and find a significant relationship between the low frequency TSI forcing and the NAO with a time lag of more than 40 years for the response of the NAO. Such a lag is larger than the around 20-year lag suggested in other studies. We argue that this lag is due, in the model, to a northward shift of the tropical atmospheric convection in the Pacific Ocean, which is maximum more than four decades after the solar forcing increase. This shift then forces a positive NAO through an atmospheric wave connection related to the jet-stream wave guide. The shift of the tropical convection is due to the persistence of anomalous warm SST forcing the anomalous precipitation, associated with the advection of warm SST by the NORTH PACIFIC subtropical gyre in a few decades. Finally, we analyse the response of the Atlantic meridional overturning circulation to solar forcing and find that the former is weakened when the latter increases. Changes in wind stress, notably due to the NAO, modify the barotropic streamfunction in the Atlantic 50 YEARS AFTER SOLAR VARIATIONS. This implies a wind-driven modification of the oceanic circulation in the Atlantic sector in response to changes in solar forcing, in addition to the variations of the thermohaline circulation.” C. Conclusion: 1st Peak of the last high solar activity (the highest of approximately 8 thousand. years!) was in the 60s of the twentieth century - and thus 40-50 years emu ... ... after about 40 - 50 years will therefore save the Eskimo from “the shackle” of ice? 2nd So the present "unprecedented" melting of Greenland's ice is (mostly) the effect of natural changes throughout the NH, and not without significance here is my favorite LTC-LNO: The complex dynamics of the seasonal component of Earth’s surface temperature, Vecchio et al., 2010: “The dynamics of the climate system has been investigated by analyzing the complex seasonal oscillation of monthly averaged temperatures recorded at 1167 stations covering the whole USA. We found the presence of an orbit-climate relationship on time scales remarkably shorter than the Milankovitch period related to the nutational forcing. The relationship manifests itself through occasional destabilization of the phase of the seasonal component due to the local changing of balance between direct insolation and the net energy received by the Earth. Quite surprisingly, we found that the local intermittent dynamics is modulated by a periodic component of about 18.6 yr [... !!!] due to the nutation of Earth, which represents the main modulation of the Earth’s precession.”Moderator Response: Please reduce the lengths of quotes in your comments. Instead, summarize and provide links or citations to the sources. -
canbanjo at 22:59 PM on 3 August 2010Visually depicting the disconnect between climate scientists, media and the public
Poptech, OK so you have added the word 'alarm' to the title of your list. I understand you are not questioning AGW evidence. I would still really appreciate it if you could identify the most persuasive papers that show that we do not need to be alarmed by AGW. Otherwise it is difficult to be convinced. Thanks -
JMurphy at 22:16 PM on 3 August 2010On Consensus
Another good model prediction here ("Quantifying the uncertainty in forecasts of anthropogenic climate change", 1999/2000), particularly Figure 3. This was referred to in a recent GUARDIAN article. -
OPatrick at 22:10 PM on 3 August 2010Why I care about climate change
John, it surprises me that anyone should need clarification of your reasons for writing on climate change - your passion, sincerity and integrity shine through in your posts and in your moderation and speak clearly of your underlying humanity. I'm an atheist and many years ago I'd have held your religion against you, but over the past couple of decades the growing realisation of the impacts of climate change has led me to re-evaluate my world view. I remember one particular epiphany came for me in the consumerist frenzy of pre-Christmas shopping in our city centre. I saw a bloke standing in the midst of the heaving hoards with a placard "God is Love" and realised I had more respect for him than anyone else around me. There is an undeniable connection between climate denialism and the religious right, particulalry in the US, but I believe this has little to do with religion. It is not their religion that informs their politics, but perhaps their politics that informs their religion? I am disturbed when I see someone arguing that we should not worry about climate change because God has given us the rainbow, but I have come to see that this is not the argument of religion, but using religion to make an argument. Climate change has also turned me away from being an environmentalist. When I was in my teens I was aware of climate change but had equal concerns for protection of individual species and forest environments. Now all these concerns are peripheral at best and it is the overwhelming human suffering that concerns me. I used to be staunchly, and probably ideologically, anti-nuclear, but now am only so on balance. My over-riding ethos now is sustainability. My children are of course a focus for this, but sustainability itself is the goal. I discover this in myself through a phenomenological approach. -
chris at 21:42 PM on 3 August 2010On Consensus
nhthinker at 21:08 PM on 3 August, 2010 Making too much of the comparison between the predictive abilities in medicine and climate science is pretty fruitless. One can address such comparisons but we should be much clearer specifically on what we are talking about. Your "fortune teller" jibe is way off base. If we consider models and their predictive abilities (and the Gavin Schmidt quote), we can be much more specific: We have a high degree of certainty that enhancing the greenhouse effect will cause the Earth to warm all else being equal, and have rather strong evidence based on analysis of historical [CO2]/temperature relationships that the climate sensitivity (equilibrium Earth temperature response to doubling [CO2]) is at least 2 oC. The most likely value based on our understanding is 3 oC and there is lesser likelihood that it is above 4.5 oC. Those values are pretty well constrained by a large body of evidence. Since climate models are parameterized according to our best understanding we are not surprised that they have so far done pretty well predictively. A major uncertainty (that Dr. Schmidt is referring to) is the various elements of the climate system, especially the oceans, which result in inertia in the response to forcing. Thus we have higher certainty about the amount of eventual warming, than the temporal progression of warming, although the reasonable success of current models (and even Broecker's 35 year old back-of-the-envelope calculation) indicates that we have a pretty good understanding of the essential energy balalnce of the climate system. One could argue that this compares favourably with many aspects of medicine. If one considers a diagnosis of cancer, for example, and considers an expert prognosis, the predictive elements are not a million miles from those involved in predictive climatology. The specialist may well have a high degree of certainty about the outcome (e.g. a cancer that is a high mortality), but will be less certain about the temporal progression of the response. S/he might be able to give 1 year, 3, yr, 5 yr chances of survival, but there will be a range of possible projections that involve interperson variability (genetics, lifestyle, personality) and other contingent happenings. Much in the way that the a climate projection might be completely scuppered by an unpredictable series of massive volcanic eruptions, so the medical prognosis might be scuppered by unanticipated future events (the patient might be run over by a bus)... -
nhthinker at 21:08 PM on 3 August 2010On Consensus
If a science has lots of models, which even the advocate is not confident in its predictive ability, then the science is clearly not reached a 4.5 to 5 level of confidence. If scientists start saluting a model that produces 90% long range results, then the science is reaching the 4.5 to 5 level. Broeker's analysis was directionally correct. I do not know anyone that is claiming CO2 has no impact: the primary issue is the accuracy of the level of impact. The advocates here seem to fall into the fortune teller's trap. There will always be some accurate prediction of of future events, especially when you have thousands of predictions to choose from. Much of the politics of the issue focus on taking extreme predictions out of context to intentionally scare people. The emphasis for a science to reach the stature of a 4.5 to 5 standard needs to be cold and calculating aspects of the math involved. From Gavin Schmidt's article on Hansen's predictions: But can we say that this proves the model is correct? Not quite. Look at the difference between Scenario B and C. Despite the large difference in forcings in the later years, the long term trend over that same period is similar. The implication is that over a short period, the weather noise can mask significant differences in the forced component. This version of the model had a climate sensitivity was around 4 deg C for a doubling of CO2. This is a little higher than what would be our best guess (~3 deg C) based on observations, but is within the standard range (2 to 4.5 deg C). Is this 20 year trend sufficient to determine whether the model sensitivity was too high? No. Given the noise level, a trend 75% as large, would still be within the error bars of the observation (i.e. 0.18+/-0.05), assuming the transient trend would scale linearly. Maybe with another 10 years of data, this distinction will be possible. However, a model with a very low sensitivity, say 1 deg C, would have fallen well below the observed trends. I'm curious if Gavin Schmidt thinks Climate science has reached the predictive ability of medical science. I kind of doubt it based on what he wrote in the article. Anyone here with enough connections to ask him? -
Stylo at 21:07 PM on 3 August 2010Visually depicting the disconnect between climate scientists, media and the public
doug_bostrom, #77, From Doran:An invitation to participate in the survey was sent to 10,257 Earth scientists. ....With 3146 individuals completing the survey, the participant response rate for the survey was 30.7%.
Voluntary response; not a random sample. They also whittle it to 8.5% (climate scientists) + 5% (publish in climate science) of the 30.7% who responded. 12.5% times 30.7% is 3.8% of the original. It's not really surprising that those who have the most to gain from actively publishing in a field promote the scare hardest.
Plant stomata frequency estimates of past [CO2] have large uncertainties (e.g. +/- 30-60 ppm; see a recent analysis of reconstruction uncertainties in Betula nana leaves). I think these studies are fine, and useful for estimating broad atmospheric [CO2] levels (or changes in [CO2] levels) in the deeper past, but one should accept that these are not precise measures.Plant stomata are a lot noisier than ice cores. One doesn't just throw out the high frequency data in signal processing just because it's noisy.
The NASA AIRS comparison is misleading since these are generally shown as snapshots. If one averages a full years worth of AIRS data, then the yearly averaged difference between polar and equatorial (say) [CO2] is only a few ppm. It's not reasonable to compare AIRS snapshots with ice core data (or stomatal data for that matter!) which is significantly temporally averaged.Then maybe you can show me an AIRS image that shows the polar regions to have higher CO2 levels than the mid and low latitudes. If it all averages out over the year, the polar regions would have to have higher CO2 levels at some point during the year. Every daily AIRS image I've seen, shows the polar regions to have 15-20 ppmv less CO2 than the mid and low latitudes. Getting the monthly average differential down to 5-10 ppmv and the annual average differential down to a few ppmv is a neat trick, considering how sparsely sampled the polar regions are.
Obviously the mechanism for sealing off atmospheric samples in ice cap or glacial firn results in a considerable multiyear averaging of the atmospheric [CO2]. In the high resolution Law Dome core the averaging is smallish, whereas in the deep Antarctic cores the averaging may encompass a large number of years (can't remember off hand, but this may be a hundred years or more???).It can vary from a few decades to more than two thousand years.
However considering the high resolution Law Dome data and the last couple of thousand years, I don't see any basis for concluding that the ice core data is biased low as you suggest. Yes, it's smoothed (it's something like a 10 year running mean); but (just like contemporary [CO2] variation), we expect rather low amplitude variability in [CO2] at high resolution. Yes, the natural variability (likely largely ENSO-related, with perhaps some significant wildfire variability) encompassing a few ppm will have been smoothed out. But it's not reasonable to think that we are missing large jumps and falls in [CO2], apart from anything else, because largish non-ENSO-related increased [CO2] levels take a long time to drop, and so they should stil be observed in cores. In any case if we're not seeing them (i.e. high resolution, large amplitude jumps and falls in [CO2]) during the last 50 years of very high resolution measurement, what is the basis for expecting that these occurred in the past?We don't see those jumps in the plant stomata data either over the last 50 years. The stomatal response is consistent with a steady increase in atmospheric CO2 over the last 60 years... ]
Wagner F, Dilcher DL, Visscher H (2005) Stomatal frequency responses in hardwood swamp vegetation from Florida during a 60-year continuous CO2 increase. Am J Bot 92:690–695.
While species were less responsive to CO2 changes, the stomatal response of M. cerifera very closely tracked the actual changes in atmospheric CO2.
Hopefully the West Antarctic Ice Sheet Divide Ice Core Project will yield higher resolution data (similar to GISP2) over the last 50,000 years or so. This may yield a CO2 "signal" similar to the stomata or something in between the lower frequency cores and the stomata.
Incidentally, I don't understand the reference to "skeptics" in your last paragraph. These guys/gals are just scientists working to improve their methodologies and obtain insight into the past. I don't think one should adopt the false notion that science is composed of groups of people that have one view of the science and others that are "skeptics".The first post in this thread says:
The skeptic argument... Plant stomata show higher and more variable CO2 levelsThat's actually what the science says. Hence, my reference to "skeptics."
If the group of people you refer to were "trying to debunk AGW" they would be wasting their careers. Science simply doesn't work like that...Actually, that is exactly how science works. To quote Einstein, "No amount of experimentation can ever prove me right; a single experiment can prove me wrong." Science is all about skepticism and debunking (AKA testing).
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