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Comments 116801 to 116850:

116801. dhogaza at 04:15 AM on 22 June 2010
        How Jo Nova doesn't get the CO2 lag
        

        The multiplier is claimed to be water vapor, which is theorized to increase CO2 temperature effects by a factor of three. There is no defense of crisis theory in the claim that CO2 behaves like everyone agrees it does.

        Beyond the fact that there's a lot of good reasons to expect relative humidity to, on average, remain roughly constant as temperatures warm ... There are detailed satellite observations to back it up, as NASA reported last year. A very large number of observations at various altitudes checked against model predictions showed that water vapor feedback was operating almost exactly as models predict. robhon:

        Roy Latham... I don't know where you get the 0.75C for doubling CO2. There are at near a dozen papers listed on this very website that put that figure closer to 3C.

        He's talking about direct warming without feedbacks, which actually is "oneish" C, not 0.75C. The 3C figure is due to feedbacks, the major one being water vapor, as Roy points out. However, far from there being "no defense" of this, as I mention above, detailed satellite observations strongly support it. Roy says:

        Moreover, claims that CO2 was the cause of past interglacial warming, per Al Gore, are wrong. It was the effect, not the cause. It added a little to the warming as we would expect.

        I doubt Al Gore misstated the science as badly as Roy says, but it doesn't matter, we care what scientists, not Gore, have to say. And scientists don't claim CO2 was the cause of the end of past ice ages. Rather, it's a feedback to the end of Milankovich cycles which, as you say, adds to the expected warming. Though more than "a little".
116802. e at 03:51 AM on 22 June 2010
        Is the long-term trend in CO2 caused by warming of the oceans?
        Lon, If temperatures just happen to stay at an anomaly of -.58, then yes, your model predicts no change in CO2, however consider what happens if temperatures remain "flat" at any other anomaly: Your model predicts that CO2 will continue changing forever. To summarize: if temperatures remain at an anomaly of exactly -.58, then your model predicts CO2 level will never change, if temperatures remain at any other anomaly, then the CO2 level changes forever. Also, if temperature anomaly is less than -.58, your model predicts a drop in CO2 levels, even if temperature has been increasing year to year! And the corollary: if temperature anomaly is greater than -.58, your model predicts an increase in CO2 levels, even if temperature is dropping! Does that really make sense to you? What's so magical about an anomaly of -.58 that the physics of CO2 accumulation hinges on it? This unphysical prediction is a direct result of what Ned has been telling you over and over again: your model is nothing but a hard-coded linear trend scaled by temperature anomaly. Replace temperature with any other linear trend and you can construct a model that is just as good as yours. The model has no real predictive power outside your sample set, and it certainly has no physical implications beyond a restatement of what was already known.
116803. VoxRat at 03:38 AM on 22 June 2010
        How Jo Nova doesn't get the CO2 lag
        @ Roy Latham #26:"So if the ordinary behavior of CO2 is what occurs in the atmosphere, we would expect doubling CO2 to cause about 0.75 degrees of warming." Where did that figure come from? Do you have a reference? "The "CO2 crisis" comes from a theory that something in the atmosphere multiplies the effects of CO2 above it's ordinary physical greenhouse effect. The multiplier is claimed to be water vapor, which is theorized to increase CO2 temperature effects by a factor of three" Do you have references for this? It was my impression that the "positive feedback" effect (the "multiplier") came from the fact that more CO2 -> higher temperature -> more CO2 (released from ocean) -> etc. But I'm no expert. "Moreover, claims that CO2 was the cause of past interglacial warming, per Al Gore, are wrong." Do you have references for this? Did Al Gore (or anyone else) claim that CO2 was THE cause of past interglacial warming?
116804. actually thoughtful at 03:28 AM on 22 June 2010
        How Jo Nova doesn't get the CO2 lag
        Roy, Those are comforting thoughts. John Cook laid out the science in his post above. What is your source for disputing the accepted evidence and theory?
116805. Rob Honeycutt at 03:26 AM on 22 June 2010
        How Jo Nova doesn't get the CO2 lag
        Roy Latham... I don't know where you get the 0.75C for doubling CO2. There are at near a dozen papers listed on this very website that put that figure closer to 3C. Forest 2002 - 1.4C to 7.7C Knutti 2005 - 1.5C to 6.5C Hegerl 2006 - 1.5C to 6.2C Annan 2006 - 2.5C to 3.5C Royer 2007 - 2.8C Lorius 1990 3C to 4C Hoffert 1992 - 1.4C to 3.2C Chylek 2007 - 1.3C to 2.3C
116806. Roy Latham at 02:44 AM on 22 June 2010
        How Jo Nova doesn't get the CO2 lag
        As far as I know, no scientist doubts that CO2 is a greenhouse gas. The physics of the gas is well-determined by lab experiements. Adding CO2 increases temperature logarithmically, So if the ordinary behavior of CO2 is what occurs in the atmosphere, we would expect doubling CO2 to cause about 0.75 degrees of warming. The "CO2 crisis" comes from a theory that something in the atmosphere multiplies the effects of CO2 above it's ordinary physical greenhouse effect. The multiplier is claimed to be water vapor, which is theorized to increase CO2 temperature effects by a factor of three. There is no defense of crisis theory in the claim that CO2 behaves like everyone agrees it does. Moreover, claims that CO2 was the cause of past interglacial warming, per Al Gore, are wrong. It was the effect, not the cause. It added a little to the warming as we would expect.
116807. Philippe Chantreau at 02:26 AM on 22 June 2010
        Watts it like at a climate skeptic speakers event?
        I'm not sure I agree with that. What matters most is proteins, and for that the key ingredient is nitrogen. In any case, closer examination of the "plant food" claims do not warrant the exuberant optimism shown by some. Considering that yield increases widely cited by skeptics happen between 550 and 1200 ppm and we have no idea what would happen globally with such levels, I will remain skeptical on this. If I recall, there was was no time in the Holocene with anything even remotely comparable to such CO2 levels, yet forests covered the Earth in all places where the rainfall permitted so. That does not point to CO2 as much of a limiting factor for plant growth.
116808. HumanityRules at 01:08 AM on 22 June 2010
        Watts it like at a climate skeptic speakers event?
        73 Philippe Chantreau "CO2 is no more plant food than you can serve up oxygen on a plate to people" In the process of photosynthesis the energy from sunlight is used to convert CO2 into sugars. The carbon in plant proteins, lipids and carbohydrates is solely derived from CO2. This is the starting point of all of the organic carbon in living beings. CO2 is the building block of plant food and everything else. In colloquial terms you could call it plant food without that being misleading.
116809. RickG at 00:54 AM on 22 June 2010
        Astronomical cycles
        Look, let's cut through the chase. Scaletta clearly states that in the period 1970-2000 that 60% of the warming is due to the 60 & 20 year cycles while 40% is due to human causes. In other words a full 0.3 of 0.5 deg C is attributed solely to Scaletta's cycle. For that claim to have any validity, I would expect to see a 0.3 deg C increase in a 30 year period in relation to that cycle every time in addition to any other forcings. Conversely, I would expect to see a 0.3 deg C. drop at the bottom of that cycle in a 30 year span as well. I don't see it. Anyone?
116810. tobyjoyce at 00:03 AM on 22 June 2010
        Watts it like at a climate skeptic speakers event?
        @Arkadiusz Semczyszak Please explain, if "Even some of the IPCC scenarios IV assume increased precipitation in many deserts, arid zone (including the Sahel zone)", as you say, how can a paper finding that outcome be a refutation of AGW? Global extrapolation from a local study is risky. Better to see it as another piece of a very large and complex jigsaw. Does this particular piece not fit with the rest of the jigsaw? I think it fits, or at least does not contradict our growing understanding of the picture. Do you disagree?
116811. Arkadiusz Semczyszak at 23:59 PM on 21 June 2010
        How Jo Nova doesn't get the CO2 lag
        ... not a single word about the solubility ...
116812. Arkadiusz Semczyszak at 23:56 PM on 21 June 2010
        How Jo Nova doesn't get the CO2 lag
        Whew ... if only it were so simple ... ... one of many examples that it is not ... ... but it is my favorite. During the warming increases significantly the amount of shelf seas, Epeiric arise (epicontinental sea - in the Cretaceous). Oolite disposal of CO2 is maybe more efficient, maybe faster than by solubility in cold oceans ... Another eight thousand. years ago, Lake Chad had an area of the Caspian Sea ... Recent trend in the global oceanic sink for CO2, Quere, 2009: "On a time-scale of decades, the global oceanic sink for CO2 is limited primarily by the rate at which oceanic circulation transports carbon from the surface to the deep ocean." "The exact fraction absorbed by the oceans depends on the re-organisation of the natural carbon cycle. Evidence from the geological past suggests that the oceans store less CO2 when the earth's temperature is warm. It is thought that the reduced ocean storage is driven by changes in the Southern ocean circulation, although the exact mechanism is NOT YET RESOLVED. [??]."
116813. Ken Lambert at 23:44 PM on 21 June 2010
        Astronomical cycles
        Chris#43, Albatros#48 Marcus#53 Owl905#68 You all had better go back and read the "Robust" thread here: http://www.skepticalscience.com/Robust-warming-of-the-global-upper-ocean.html Far from being 'flawed', both BP and I have shown the impossibility of the jumps in the 0-700m OHC charts being TOA imbalances over such short periods which happen to coincide with the change from XBT and the full deployment of Argo in 2003-04. The jump of about 7E22 Joules in a 2 year period is most likely an instrument offset error. Take out the jump and the OHC is pretty flat for the whole 16 year period - and the more accurate Argo data from the 6-7 anlyses starts to converge on a flatter trend over the last 6 years (Fig 2). Dr Tremberth's paper (Aug09) oft quoted here also summarises the sea level story in Table 1. The total land ice melt accounts for about 2.0mm of the total 'observed' 2.5mm rise per year (2004-2008), leaving about 0.4-1.2mm for the ocean thermal expansion. These numbers have wide error bars eg. 0.8mm +/-0.8mm is quoted for steric estimates. Chris and I have debated the TOPEX - Jason satellite transition - and if the two trends are linearized - there is a flattening in the Jason record closer to 2.0mm than 3.2mm per annum often quoted over the combined record. There is also the probably of an offset error in the transition. Lack of steric rise means lack of thermal expansion means lack of take-up of heat in the oceans which means - globally - lack of TOA imbalance - which means lack of global warming over the last 6 years at least. Cop that for reductive thinking. And finally if the current 'lack of warming' over the last 6 years or so is due to Chris' bottoming of the 11 year Solar cycle, there is a the difficult question of scale of forcing imbalance of Solar (0.25W/sq.m)compared with Dr Trenberth's 0.9W/sq.m overall 'observed' imbalance. In other words, if a drop of 0.25W/sq.m (top to bottom) of the 11 year cycle, flattens global warming over the last 6 years or so, then that suggests a similar warming figure was acting at the top of the cycle ie. about 0.25W/sq.m, which is a lot less than the Trenberth TOA imbalance of 0.9W/sq.m.
116814. Arkadiusz Semczyszak at 23:12 PM on 21 June 2010
        Watts it like at a climate skeptic speakers event?
        "The truth is unfortunately not that simple ..." I only very briefly supplements Argus: The papers: A recent greening of the Sahel—trends, patterns and potential causes, Olsson et al., 2005: "Speculation [...] about the climatology of these droughts is unresolved, as is speculation about the effects of land clearance on rainfall and about land degradation in this zone. However, recent findings suggest a consistent trend of increasing vegetation greenness in much of the region. Increasing rainfall over the last few years is certainly one reason, but does not fully explain the change. Other factors, such as land use change and migration, may also contribute. [?!]" Even some of the IPCC scenarios IV assume increased precipitation in many deserts, arid zone (including the Sahel zone). Recently it was found that the Atacama desert was inhabited by people - 11-9. thousands BP ... For me, so skeptics (such as described here - "brilliant": and the fact that - ruthless ...) are needed, if only to refute the MYTHS (e.g. - Sahel - here probably AMO phase decides) - associated with AGW ...
116815. tobyjoyce at 23:09 PM on 21 June 2010
        Watts it like at a climate skeptic speakers event?
        @JMurphy, Bringing scientific questions into public fora or courts of law is a strategy of denialism, pioneered by tobacco deniers and creationists. These arenas are not suited to the settling of scientific questions, as fiascos like the OJ trial have shown. Appeals to emotions, ad-hominem attacks, twisting evidence, "spinning" events, pleading victimization, scapegoating and smearing are all legitimate debating and rhetorical tactics. And of course, they have been used by scientists, and do influence them, who are only human. In general these strategies are ruled out by science in preference to consideration of the evidence alone. Also, referring to marty's earlier comment, science is not a democracy. It is a complete meritocracy where the "victory" goes to the theory (idea, research program, or hypotheses) that fits the known facts. You can think of it as a fierce Darwinian struggle of ideas, where the winner is the one best adapted to the evidence. It is not in the least high-handed or arrogant to make you aware of that. Public debate has to be about public response to the scientific consensus, as it usually is in the case of the risk of a new flu epidemic, or the construction of a new nuclear power station, or a star wars defense system etc.
116816. HumanityRules at 22:59 PM on 21 June 2010
        Watts it like at a climate skeptic speakers event?
        71 Marcus "the negative impacts of increased senescence as climates warm. Nor have you dealt with the problems of increasing water scarcity (which is a *major* issue here in Southern Australia)" I'll give it a go at calming your alarm. Here's wheat yields in SA over the past 150 years. A steady increase punctuated by major losses due to drought. The worst being 1915. Even in the worst of times in the late 20th century we're still more efficient than the best of years in the first half. This is because the improvements in farming (and plant breeding) has meant that to some extent we can mitigate the worst that nature can throw at us. I remember reading a paper on wheat strains (I know, exciting stuff) which lists the most used strain in each decade. Every decade the strains changed as better strains became available. I remember the paper because I was surprised by the amazing rapid pace of change. This process won't stop under the worst scenario of AGW. This is often forgotten. Just back to SA. I think some of the poor interstate politics surrounding the Murray-Darling basin have contributed to SA farmers not getting their fair share of water. In fact a general argument could be made that Australian politician have been complacent about managing water for their growing population for many decades, regardless of what extra strain AGW might have placed on it. This isn't a climate problem, it's one based on poor human decisions. You let the politicians off the hook by blaming it all on AGW.
116817. Arkadiusz Semczyszak at 21:59 PM on 21 June 2010
        Astronomical cycles
        @Marcus - sunspot ... The sun also, for instance through its "active" gravitational effect on Earth's volcanic activity - aerosols - and such as, cause e.g. transferred those to the activity of "direct" (TSI) Sun - LIA ... Please look at this picture: http://www.nature.com/nature/journal/v443/n7108/fig_tab/nature05072_F5.html (with: Variations in solar luminosity and their effect on the Earth's climate, Foukal et al., 2006, Nature). For example, year 1150 - 1300 - is nearly complete lack of direct correlation: sunspots - global temperature. Shifts in time are all too visible - even when compared with the newer (than in this work) temperature reconstructions. Present here the natural pattern of origin of the current warming - an explanation which will be dominated in the forthcoming report NIPCC (not the theory of Svensmark - like now). The increase in solar activity (TSI), is closely correlated with interactions of the planets in our star. Additionally, it causes (parallel - or cyclically delayed in time - the TSI) changes in the gravitational system the Sun - the planet - the Moon. Currently, a number of cycles is the most important series of changes to the layout Millennium - "Millennium" x multiples - it requires also, or the strongest short cycle - 60 years. The gravitational influence of solar system planetary radius of THC changes will affect the NAO, AMO, PDO, ENSO, about AO, etc. (Long-term natural variability and 20th century climate change, Swanson, 2009,: "Variability associated with these latter processes, generally referred to as natural long-term climate variability, arises PRIMARILY FROM CHANGES IN OCEANIC CIRCULATION.") Currently, more energy is put to NH. Warming to NH - particularly the Arctic - is greater than in SH. They will run a strong positive feedback associated only with the NH (not in the SH): - Increases the area of the lower albedo (less sea ice, glaciers are melting); - Increased evaporation - the greenhouse effect (on the NH is more land than the SH, the lands have a lower thermal inertia compared to the oceans ...), greater CO2 emission from the richest soils in carbon ...; Moreover, when such changes in THC - AMO - of ENSO, El Nino often occurs - it is stronger - the ocean gives more (and faster) energy ... In conclusion, in our view, the system planets - the Sun - Earth - Moon - by affecting the atmospheric and oceanic circulation, corresponds to (mostly) for the increased capacity of the Earth's atmosphere to heat accumulations (...). - and with that Marcus (and al.) should discuss. .. and for me is the impact of THC on the MOON seems to be the most important ... P.S. In addition, I recommend the discussion: Dickman, 2006, Short and longer-term planetary effects on Sun and Earth; Mackey, 2009, The Sun's role in regulating the Earth's climate dynamics.
116818. Argus at 21:00 PM on 21 June 2010
        Watts it like at a climate skeptic speakers event?
        "Marcus" seems very focussed around the fossil fuel industry, as if the industry itself, and its hunger for profits, is the sole reason why the countries of the world are using so much coal and oil (and not their need for energy). Some Marcus quotes from this post: "...*rather* than the fossil fuel industry should lose even a single dollar of their mega-profits..." "...promulgates another myth of the fossil fuel industry..." "...rather than suggest that the fossil fuel industry should have their profits cut by so much as a single dollar!" "...those who're trying to push fossil fuel industry propaganda down our throats..." "...the message being how good the fossil fuel industry is being to us..." I would think the problem with CO2 emissions from fossil fuels lies deeper than with the needs for industry profit. In China they open up a new coal-fired plant roughly every week, and burn two billion tons of coal a year. USA is in the same league as China (with about one billion tons). In addition they use 3 million cubic metres of petroleum per day. German energy supply is largely based on burning brown coal from local strip mines. How can we replace this growing need for energy in the world with other sources? Denmark is one of the world leaders in wind power, but they still only get 20% of their energy from the wind. How do we convince American drivers that they should drive their cars less? USA has more than 250 million passenger cars (with their use even encouraged by low taxes on gasoline). They already think their gas is too expensive. How many in this forum drive a car, and travel regularly by air? Should you continue doing so? Have you considered basing your own life on energy only from the sun - including wind and water - (or from radioactive fuel, if you like that stuff)? If you already have, how are you planning to convince all the millions of others in your country to do the same?
116819. JMurphy at 20:43 PM on 21 June 2010
        Watts it like at a climate skeptic speakers event?
        marty, the debate about the science is taking place within the scientific community and can be seen by looking at the papers published on the subject of Climate Change. There, you will see where the evidence lies. I have never understood how anyone can claim that they aren't able to work out what the science says unless there is a public debate or some sort of legal case, etc. Perhaps we should also debate as to whether we accept Evolution or the origins of the Universe ? As for your views about the world ending up in a 'Green dictatorship, backed by an evil scientocracy' (I paraphrase), I just wonder how you even think that such a thing is possible ? It sounds as if you have read (and believed) some so-called skeptical expert (perhaps Monckton ?) pontificating on the affects of limiting the output of CO2, claiming that it will lead to a Marxist/Leftist New World Order taking us back to the Stone Age ! Otherwise, where do you get your ideas on that from ?
116820. tobyjoyce at 19:08 PM on 21 June 2010
        Watts it like at a climate skeptic speakers event?
        MattJ @60 I must concede on that one (sigh!):( My point was intended for an ideal world, where politicians determine policy based on scientific input, not on what plays in the media or with rich backers.
116821. tobyjoyce at 19:06 PM on 21 June 2010
        Watts it like at a climate skeptic speakers event?
        marty @59, Given that a "balanced" public debate is no longer possible, there is also the "prudence principle" to be taken into account. The prudence principle says that you should take steps to mitigate or prevent calamitous outcomes, even if they are unlikely. That is the principle behind taking out any sort of insurance, like against a road accident, housefire or serious illness. The probability of each of these events is very low, but the outcome is so bad that insurance is advisable. Now there is a reasonable methodology to working out how much of your income you should devote to insurance, that is what actuaries do. Some insurance policies are also a means of saving money. That is a good analogy for taking action on global warming. While we have the time, we can start investing in an insurance policy (alternative energy) that will pay off in the long run. Should the adverse circumstances not pan out, we still have the savings. My fear, which is turning into a conviction, is that global action will not happen until they evidence is overwhelming. At that point, some of the most adverse effects may be irrversible.
116822. Glenn Tamblyn at 18:47 PM on 21 June 2010
        How Jo Nova doesn't get the CO2 lag
        A few extra things that can be observed from the Ice core shown in Jo's SH. Look closely at the point where the warming first starts. Temps & CO2 both start to move up at around the same time. It is only later that the Temp trend starts to lead the CO2 trend. Look also at the difference between the warming phase, where CO2 follows Temp quite well vs the cooling phase where the relationship between CO2 and Temps is more indistinct. This actually matches what we might expect. At the bottom of the cycle, huge ice sheets cover large areas of the world, resulting in a low Albedo. A Milankovitch cycle kicks things off and Temps & CO2 start to rise. Also not shown here is possible methane release due to melting permafrost at the edge of the ice sheets. Methane is a powerful but short-lived greenhouse gas which then converts to CO2. So methane could give a significant warming while only leaving a small CO2 residual in the ice core. Also, the ice sheets are so thick that it may be millenia before they start to thin enough and break up. An ice sheet 100 metres thick has essentially the same albedo as one 1 kilometre thick. So they are quite likely shrinking in mass for long periods before any significant albedo change cuts in. So a quite likely sequence of drivers during the warming phase is Milankovitch then Methane then CO2 then Albedo Change. Now look at the cooling phase. The Temp signal looks much noisier during the early stages, and CO2 doesn't drop much at all. In fact it is relatively stable while Temps climb further at the end of the warming then drop. What could drive this? Consider; The ice sheets have retreated, leaving bare rock. It will take reasonable periods of time for any meaningful amount of soil to be created there. Then vegetation starts to colonise the exposed land. Not just lichens but later forests. Large Carbon stores. So at the end of the warming phase it is quite possible that CO2 levels were being held down by their absorption by the expanding Biomass while Temps are being driven further up by albedo change as the ice sheets really start to collapse. As things start to cool, colder weather returns and more snowfall. A few metres of snow has the same albedo as kilometer thick ice sheets. So albedo change can now be a driver very early in the process. And as Temp's drop, you would expect the oceans to start reabsorbing CO2. But there is a store of carbon in the extra biomass that grew during the interglacial. As the cooling progresses and this biomass starts to die-back, this is a store of carbon that can be released into the environment, offsetting to some extent the drawdown by the oceans, holding CO2 levels up. The noisy Temp' signal during the early part of the cooling phase is what you might expect when natural climate varibiality is occuring during the cooling. A 50 year warmer phase for example could easily remelt snow and ice accumulations when they are still relatively thin, resulting in an oscillation of albedo as a consequence of climate variability. This would only settle down once the degree of cooling is greater than natural variability and remelt cannot be completed; then the accumulation of ice would start in earnest. But none of these kinds of considerations fit into the simplistic meme that 'CO2 follows Temps, so Temps cause CO2'. Sometimes the world of the Climate Sceptics is a comfortingly simple world. Maybe that is its appeal. MattJ To your comment about positive feedbacks, the answer is the second - change the gain. In fact, as long as the gain is less than 1, it will always be a limiting feedback. Examples of how the gain is limited in the climate wrt the ice cores. Albedo can only change due to ice melt until the ice is all melted - then no more feedback. And as ice retreats to just the polar regions the feedback is declining anyway. Similarly albedo change during the cooling phase is limited since ice sheets simply can't spread that far over water. Co2 gain is limited during warming by the logarithmic nature of its radiative effect. Similarly, as cooling progresses the reduction in the volume of the oceans due to sea level fall because more ice is forming on land starts to limit how much CO2 can be bound up in the oceans. So too biomass decline in cold climates will limit the amount of carbon stored in biomass, making it harder to sequester CO2. In the longer time scale, chemical weathering of rocks that removes CO2 from the atmosphere via the formation of Carbonic Acid will be slower in cold climates, faster in hot ones. And balanced against this is the ongoing slow outgassing of CO2 from vulcanism.
116823. Megan Evans at 16:40 PM on 21 June 2010
        Watts it like at a climate skeptic speakers event?
        For comparison - Monckton tickets were $150 a head
        Response: Lord, how that Monckton put bums on seats! :-)
        
116824. Megan Evans at 16:34 PM on 21 June 2010
        Watts it like at a climate skeptic speakers event?
        doug_bostrom - Not sure what the total cost will be for the CS Party to bring Watts out here, but the ticket itself was $20. Looks likely they will make a hefty loss.
116825. David Horton at 16:32 PM on 21 June 2010
        How Jo Nova doesn't get the CO2 lag
        Thanks Chris, having seen the latest reconstructions of the possible past extent of oceans on Mars it occurred to me to wonder if the initial loss of water was due to an early greenhouse effect.
116826. Doug Bostrom at 16:06 PM on 21 June 2010
        Watts it like at a climate skeptic speakers event?
        BTW, what was the cost of having Watts in to speak? I'm thinking of Christopher Monckton, who cost the "Climate Sceptics Party" something like $100k AUD for his roadshow. Only $20k or about $2500/performance directly to Monckton, mind, the balance being spent on travel and accommodation expense. Does Watts command a similar fee? If I were a show promoter looking at the empty room pictured above I'd be squirming.
116827. Chris Colose at 15:40 PM on 21 June 2010
        How Jo Nova doesn't get the CO2 lag
        David, the current mainstream paradigm is that this is what happened in Venus' early history. This is the only planet is our solar system that experienced such a fate, although presumably there are many other planets outside our solar system which can support an atmosphere and receive enough solar radiation for this to be relevant. On Mars, almost the opposite occurred. The climate evolution of Mars is a tug of war between the sun gradually brightening over geologic time, and the loss of its atmosphere. Geologic evidence for the presence of water suggests that the stronger greenhouse effect temporarily won out in its distant past (although quantifying the levels of CO2 or other greenhouse gases needed to get ancient Mars above freezing is a long-standing issue in comparative planetology and not yet possible with current spectral database information). However, the atmosphere has slowly faded away, and today is only a very small fraction of Earth's atmospheric mass. Mars will never again have any significant atmosphere, and thus cannot generate any meaningful greenhouse effect even if what little of it remains is mostly CO2...The planet is now extremely cold, so in no sense can it be said to have experienced a runaway greenhouse. All the water is frozen beneath the Martian sand. It will take a long time for the sun to keep brightening for Martian temperatures to approach Earth-like values. For Earth, the range of temperature and CO2 feedback variation that we have experienced in the past are rather small from the perspective of planetary climate. Sure they can get you in and out of an ice age (even the PETM which was one of the best examples of a hellish hothouse and abrupt GHG-induced warming was nothing compared to the temperatures observed on Venus or Mercury, and that cooled down relatively rapidly); however there's a strong converging limit as to how much CO2 feedback you're going to get out of the oceans just by raising the temperature. One interesting discussion on this is here. The domain of interest when discussing the CO2 feedback to warming over the glacial-interglacial cycles should not be taken too far outside the bounds of glacial-interglacial cycles, as things are going to change over different timescales and ranges of temperature. It isn't as though temperature and CO2 are going to keep rising forever, and clearly the ice-albedo feedback diminishes with time and goes to zero when there is no more ice. Just as when you drop a bouncing ball to the ground and let it go, eventually the height of each successive bounce decreases with time. Prior to the point when it stops bouncing completely, you get to the point where it just bounces a millimeter or so up and down for a little while and you can still calculate a number for the total distance that ball went up and down over the course of its journey. This is how feedback (radiative or carbon-based) tend to work on Earth, and is quantified in a manner similar to Jim Eager's post in #10. If you define a feedback factor "f" which diminishes with time (so f < 1) then an example converging series looks like 1 + f + (f^2)+(f^3)...(f^n). Eventually you can add up an infinite number of numbers and still converge to a real finite number (!) since f raised to the power of n becomes exceedingly small when f is between zero and one, and n becomes large. By the way, if you get an hour or so to sit and watch an excellent climate talk on CO2's role over geologic time, you should definitely watch Richard Alley's a href="http://www.agu.org/meetings/fm09/lectures/lecture_videos/A23A.shtml">presentation presentation at the recent AGU meeting. It is very interesting and informative.
116828. scaddenp at 15:24 PM on 21 June 2010
        How Jo Nova doesn't get the CO2 lag
        thingadonta - why do you get this idea? The climate models always work on premise that climate is response to all forcings and temperature feedbacks happen irrespective of forcing. See 2nd paragraph of Chris's post above. The estimates of sensitivity from past climate change HAVE to work on basis of solar induced feedbacks. One of the arguments against low sensitivity is that you couldnt get ice age cycle without strong feedbacks as the forcing is so weak. The question really is about WHICH forcings are most dominant at the moment.
116829. Philippe Chantreau at 15:16 PM on 21 June 2010
        Watts it like at a climate skeptic speakers event?
        Since you guys did the reading, can you clarify whether these results were obtained at 550ppm but with current ambient temps or at temps that would be consistent with 550ppm? Btw, let's drop the plant food theme. CO2 is no more plant food than you can serve up oxygen on a plate to people. Plant food is made of nutrients, mostly nitrates and phosphates, is it not?
116830. thingadonta at 15:11 PM on 21 June 2010
        How Jo Nova doesn't get the CO2 lag
        #14 Ned. My concern is that positive feedbacks seem to only ever be applied to greenhouse gases, not to eg the sun. This is inconsistent. For eg, if we stopped all greenhouse gas emmissions now, we would still get warming for several decades because of all the heat already gone into the oceans. But why can't this also apply to changes in insolation/output from the sun 1750-1950, eg from when the sun stopped increase in output from about 1750-1950s- to the late 20th century, or after the end of ice ages, to swamp the relative effects of greenhouse gases, in both cases?
        Response: You're completely correct that positive feedbacks don't apply just to greenhouse gases. They apply to any warming whether it be from the sun or greenhouse gases.
        
        So there is a time lag after the sun stops increasing. A paper by Sami Solanki compares the temperature record to solar activity over the last 10,000 years or so. He finds a lag of around a decade - when the solar output changes, it takes around a decade for the temperature to come back to equilibrium.
        
        What happened throughout the 20th Century was the sun warmed in the first half of the century, then levelled off in the 1950s. So what we expect to see if after the sun leveled off in the 1950s, if the sun was the major driver of climate over the 20th Century, we would see global temperatures continue to rise for a decade or two (or three) as it gradually approached equilibrium.
        
        Instead we see the opposite. After the 1950s, we experienced cooling then as we got further away from the 1950s, the planet's energy imbalance actually increased rather than decreased towards equilibrium. So we're going in the opposite direction to what we expect if solar changes was the main driver of climate.
        
        When I write these blog posts, I could qualify every statement along the way - point out that CO2 is not the only driver of climate every time I mention the warming effect of CO2. Mention that CO2 positive feedback is not the only positive feedback and in fact, water vapour feedback is the greatest feedback. But each post would get pretty turgid, unwieldy and unreadable with so many qualifications. Nevertheless, I do try to mention these general principles on a regular basis along with links to the appropriate pages.
        
116831. David Horton at 14:28 PM on 21 June 2010
        How Jo Nova doesn't get the CO2 lag
        "Runaway Warming" - that's interesting Chris, I'm learning a lot today in various venues. So presumably, by your definition, only Venus and Mars have experienced "Runaway Warming" in our solar system, is that right? And Earth can't. I had always taken the phrase to refer to the continuing feedback of more CO2 gives higher temps gives more CO2 and so on. And then, in addition, more warming gives release of methane, lower albedo, and so on, so that you get even more warming, and so on. That is, unless you can break the loop by dropping CO2 levels, you will find temperatures rising faster and faster to whatever theoretical maximum is possible given Earth's geography and atmosphere, and at that maximum we are all in big big trouble. It may not be "runaway" to infinity (as it were) but it is runaway as far as the well being of life forms on the planet are concerned.
116832. Marcus at 14:15 PM on 21 June 2010
        Watts it like at a climate skeptic speakers event?
        Sorry, but I really feel that other people need to see why the result of the FACE study is not as great as John D wants us to believe. Here are the grain yield results (in grams/meter squared) Drysdale: ambient 475 +/- 25/elevated 525 +/- 25 Gladius: ambient 450 +/- 25/elevated 550 +/- 25 H45: ambient 425 +/- 25/elevated 450 +/- 25 Hartog: Ambient 625 +/- 25/elevated 625 +/- 25 Janz: ambient 400 +/- 25/elevated 550 +/- 25 Silverstar: ambient 475 +/- 25/elevated 500 +/- 25 Yitpi: ambient 550 +/- 25/elevated 650 +/- 25 Zebu: ambient 400 +/- 25/elevated 500 +/- 25. So really, with the exception of Gladius & Janz, none of the varieties are showing a huge increase in grain yield in elevated CO2 conditions-once you've accounted for variability-even before we account for the deleterious effects of reduced water availability & increased senescence/heat stress due to warming. This is why I believe their overall summary (which I posted above IN FULL) is so circumspect-yet still John D wants to report these results as entirely positive. If I tried to pull that kind of spin off in my job, I'd be lucky to keep it!
116833. Marcus at 13:38 PM on 21 June 2010
        Watts it like at a climate skeptic speakers event?
        Oh John D, please do enlighten this poor "ignorant" soul (who actually works closely with farmers from across the whole of Southern Australia-& has a DECADE of experience working in the field of the Agricultural Sciences) about where I've actually "cherry-picked" the data. All I've done is to highlight the relevant data-namely the grain yield per meter squared. An overall increase in biomass is *useless* to us if its primarily restricted to vegetative biomass-given that its the seeds we primarily want. The other relevant piece of data is the protein yield, which is also not positive. Decrease the protein yield per gram of seed, & you'll need to increase your intake to get the same amount of protein. Yet we're supposed to believe this is GOOD NEWS? Only to those who're trying to push fossil fuel industry propaganda down our throats. BTW, buddy, I live in South Australia-the driest State on the driest continent on Earth-so please don't lecture me on aridity! I also note that you've got nothing to say about the acclimation they noted in the trial, or my point about the negative impacts of increased senescence as climates warm. Nor have you dealt with the problems of increasing water scarcity (which is a *major* issue here in Southern Australia) All of which suggests to me that you *know* that this is an increasing problem, but you're avoiding any mention of it so you can stay "on message"-the message being how good the fossil fuel industry is being to us by producing all this extra CO2. Guess what, its a broken record & some of us are getting sick of hearing it after its been so totally debunked!
116834. Chris Colose at 13:23 PM on 21 June 2010
        How Jo Nova doesn't get the CO2 lag
        Response to MattJ (#8) and other various comments: The usage of the terminology "feedback" is a bit different in other fields than it is often used in climatology. Further, for the commenters here discussing prospects of "runaway warming" and "positive feedback" it is important to distinguish between radiative climate feedbacks and carbon-cycle feedbacks. A few comments are going a bit astray in their descriptions so I will try to focus the posts here down the right path, though this will be mildly lengthy: First off, a "no feedback" scenario in the context of climate change is one in which the radiative forcing for CO2, solar irradiance, or whatever else is allowed to vary but you hold all variables which are climate-dependent constant (e.g., no ice melts, cloud climatology remains the same). In this case, the only response which is allowed to occur as the temperature changes is an increase in the outgoing longwave radiation (this is the Planck feedback and is a pre-requisite to come back to equilibrium at all). From this it can shown that the sensitivity parameter is inversely proportional to the 3rd power of the emission temperature of the planet, and temperature changes by about 0.25 Kelvin per Watts per square meter forcing. The forcing for a doubling of CO2 is about 4 W/m2 and thus you get ~1 K temperature rise in this simplified case. It is from this baseline which "positive feedbacks" and "negative feedbacks" are defined. If the total temperature response to a 1 W/m2 forcing is greater than 0.25 K, then we can say the net effect of the feedbacks was to be positive. If the temperature rise from a 1 W/m2 forcing is somewhere between zero and 0.25 K, then the net effect of feedbacks is to be negative. From this viewpoint the only thing positive feedbacks mean is that the final equilibrium temperature response is amplified relative to the Planck radiation only feedback case (i.e., greater than 0.25 K/W/m2). The individual feedbacks of interest here are primarily the response of water vapor, clouds, the lapse rate, and the surface albedo to global temperature change. This is the case because these things are the main components whose properties are temperature-dependent and because they also modify the energy balance of the planet. When talking about biological and other carbon-cycle feedbacks, such as ocean outgassing, methane release from the Arctic or deep ocean, changes in vegetation-- this is a bit different because in these cases you're only talking about the rapidity at which you change the greenhouse concentration. The temperature response to a doubling of CO2 depends only on the CO2 forcing and the aforementioned radiative feedbacks. A doubling of CO2 is a doubling of CO2; the only thing ocean outgassing or biological feedbacks do is modify the rate at which you get there. By the way, all of these things are feedbacks to temperature, not to CO2 (or solar, or whatever) and for the most part the sensitivity of the climate is independent of what causes it to be pushed. It is nonsensical to say "AGW proponents" (whatever this means) say water vapor feedback must be positive or that methane must be released from Arctic permafrost. The positive water vapor feedback emerges from the consequence of well-known thermodynamic relationships between the saturation vapor pressure of a condensable substance in the air, and the temperature. The logic would equally apply to any gas which is condensable on the planet/moon in consideration (CO2 can condense in the Martian poles for example, or methane on Titan). Carbon feedbacks are a bit dicier because there is no theoretical law that mandates that CO2 must be higher in warm interglacials than during cold glacial periods...it just tends to be the case...Whether a carbon feedback takes place could also depend on the initial climate state, so there is no mandate that something which happens from now until a doubling of CO2 must have also happened as you are getting out of a glaciation. Biology, permafrost, methane hydrates,etc all have their own complex physical processes and thresholds Whether we consider the CO2 change to be a positive or negative feedback to temperature depends on the timescale. Over orbital time periods CO2 tends to rise and fall in sync with temperature, but over longer geological time periods, CO2 tends to accumulate in colder regimes since weathering is less efficient. This is the silicate-weathering control on climate which is thought to be a primary factor in keeping the Earth's climate within a relatively narrow range of possible states in our 4.6 billion year history. You need water and rocks for this to work...concerning Marcus' comment, biology is not a real important control knob on Earth's CO2 concentration. Further, CO2 has been much higher than present in the last 100 million years. Prior to the ice core record you can find climates with many thousands of parts per million CO2, and these tend to be associated with mostly or completely ice free climates. Ever since the formation of the two great ice sheets, the Earth is not quite in a state anymore to be conducive to such conditions anytime soon. Re: "Runaway Warming" With this being said, to talk about "runaway" warming we need to define what that means, since colloquial usage of the term is almost always different from scientific usages of the word. In the more laid-back usage, it can mean anything from an extreme amount of warming that pushes the limits of human comfort, it can mean exceeding some socially acceptable amount of warming, it can refer to anomalously high levels of greenhouse gases in the atmosphere, or whatever. It can typically mean whatever you want so long as you are clear with your audience about its meaning so everyone is on the same level. In the scientific sense, a runaway greenhouse refers to the boiling off of a planets ocean. This occurs in response to a threshold at which the planets outgoing radiation becomes decoupled with the temperature, and when this kicks in, the planet will continue to take in solar energy at a greater rate than it can possibly emit back to space and will warm up until the oceans are lost. The threshold is often called the Kombayashi-Ingersoll limit and describes a flattening off of the radiant emission curve over a range of temperature increases. Once the whole inventory of water is atmospheric-bound (and generally lost to space) the planet can then emit radiation again to balance the incoming energy although it is now at temperatures of many hundreds or many thousands of degrees Kelvin. This clearly never occurred on Earth in the past (even when CO2 was much higher than today or when methane was rapidly released from the deep ocean or Arctic) and it is not something that can even happen today if we burn all the coal and oil. In fact, the runaway threshold is only mildly sensitive to the CO2 concentration and is mostly set by incoming solar radiation and the planets gravity. The planck radiation feedback (sigma T^4) places strong constraints on the range of climates possible for Earth under current solar conditions.
116835. shawnhet at 12:54 PM on 21 June 2010
        Astronomical cycles
        "maybe i now can see why you are focusing there. As convinient to your position you do not like to see where the bases of his paper are and rather prefer to look at it upside down. As a general rule, the begining is were one should start, not the end." It doesn't make any difference whether you start at the beginning or the end here. The facts are as I have already laid them out. Scafetta proposes *at the beginning middle and end of his paper* that temperature can be reconstructed using a quadratic trend(to represent AGW) and SSCM cyclical trend. The fact that the choice of AGW trend may be somewhat arbitrary(though less so than n=4) does not mean that his model does not do a good job in reconstructing temperature. Cheers, :)
116836. johnd at 12:27 PM on 21 June 2010
        Watts it like at a climate skeptic speakers event?
        Marcus at 12:12 PM, the Horsham trial is only one of about 30 experiments and FACE trials that have gone on around the globe over the past 20 years.
116837. notcynical at 12:20 PM on 21 June 2010
        Andrew Bolt distorts again
        Mike Hulme: Giving the impression that the IPCC consensus means everyone agrees with everyone else – as I think some well-meaning but uninformed commentaries do (or have a tendency to do) – is unhelpful; it doesn’t reflect the uncertain, exploratory and sometimes contested nature of scientific knowledge. John B at 17:01 PM: Rudd simply said "this is the conclusion of 4,000 scientists". Well it is. This is demonstrably and irrefutably true. Q.E.D.
116838. Marcus at 12:12 PM on 21 June 2010
        Watts it like at a climate skeptic speakers event?
        Oh, & am I the only person who needs to point out that a single 3-year trial, in a single location, with a single crop variety (wheat)-all under carefully controlled conditions-does not *prove* Carter's assertion that increased CO2 concentrations will be good for crop health over the long-term (especially when the overall results are far from spectacular). Carter's assertion is what we would refer to as PROPAGANDA-something certain people are more likely to believe than others.
116839. Bern at 12:06 PM on 21 June 2010
        Watts it like at a climate skeptic speakers event?
        Argus @ #45: I'm not aware of any recent studies of flooding the Qattara Depression, but here's one (Hope et al 2004) about doing the same thing in Australia with the Lake Eyre basin. It wasn't very promising...

        Away from the imposed water expanse there is no consistent or significant response in rainfall anywhere in Australia. We conclude, as did Warren (1945) that there is no evidence that large-scale permanent water surfaces in inland Australia would result in widespread climate amelioration.

116840. Marcus at 11:51 AM on 21 June 2010
        Watts it like at a climate skeptic speakers event?
        John D, the more of your posts that I read, the more convinced I become that it is YOU who needs to read this study more carefully. When you actually look *carefully* at the raw numbers, & graphs, you see the story is not as rosy as the one you want to paint. As I said before, when you account for standard deviation, the grain yield per meter squared is *not* that great when comparing 380ppm with 550ppm. Also, the study specifically claims that they saw evidence of acclimation before the end of the 3-year trial. One wonders what the impact of acclimation will be over 6-10 years at similar levels of CO2. Another point is your claim regarding growing plants in CO2 concentrations of 1200ppm. Can you provide *proof* of this extra-ordinary statement? Are you sure we're not talking about C4 plants, which make up an incredibly small part of our agriculture (most agricultural crops are made up of C3 plants, which evolved in a low-CO2 environment, so its highly doubtful that they would respond well to high CO2 over the long-term). Also, Ian is right, most of Southern Australia has winters with very short days, so shifting the growing season for Summer crops back into early to mid Winter would not help increase crop yields. Indeed, it would probably make matters *worse* (as anyone with even a modicum of knowledge of agriculture would understand). What Southern Australia also suffers from is aridity. Even without global warming, most of WA, SA, Victoria & NSW have to endure low rainfall. The warming of the last 40 years has seen rainfalls drop EVEN FURTHER, placing the long-term viability of agriculture in this region in great jeopardy. I'll reiterate, though, that what I find so HILARIOUS in your argument-John D-is that you'd rather that the rest of the world *adapt* to a high CO2 world, rather than suggest that the fossil fuel industry should have their profits cut by so much as a single dollar!
116841. Marcus at 11:33 AM on 21 June 2010
        Watts it like at a climate skeptic speakers event?
        LOL, you're accusing *me* of Cherry-picking, John D? That's rich, given that virtually every post you make here is filled with cherry picked data to "prove" your point. I've read the summary of that report, & I don't see them making the "positive comments" you're making. Please do enlighten us as to which parts of the following comment paint a rosy picture of a high CO2 world? •Increase in biomass and grain yield ~ 25% with CO2@ 550 ppm. •Less response with hotter conditions (later sowing). •No particular yield component stands out –they are indicators of the path not the destination. •Grain protein contents were lower under eCO2. •Little evidence of differences between Janzand Yitpi–these types are still sink –not source –limited. •Some evidence of differential response among cultivars –maybe high growth rates, low determinacy, (high NUE?). •Seek future types that are less sink limited and with lower acclimation response. It sounds very circumspect to me (& I should know, given that I'm a scientist myself, working in a field related to agriculture). Also, if you look at slide # 17, you'll see *why* they're very circumspect-grain yields for all varieties looked at is between 400g/square meter to roughly 700g/square meter, depending on variety. The point though is that you get a greater difference in yields based on *variety* alone than what you do as a result of increasing CO2 concentrations. Indeed, in almost all the cultivars they studied, the difference in seed yield in aC02 vs eCO2 conditions was almost non-existent *after* you account for standard deviation. When you factor in the decreased protein yield in the grain, & the reduced yields in warmer, water-constrained conditions, you see that there is little room for optimism-no matter how propagandists like yourself try to paint the picture. As I said, if you want to see the *reality*, here & now, might I suggest you come & visit the agricultural lands of WA, SA & Victoria-as I have-where many farmers are already facing ECONOMIC RUIN due to the long-term drought caused by the relatively modest warming of the last 40 years-& then you will see the difference between the fantasy propagated by the Denialosphere & the reality on the ground!
116842. David Horton at 11:32 AM on 21 June 2010
        How Jo Nova doesn't get the CO2 lag
        Nicely summarised Marcus.
116843. Doug Bostrom at 11:26 AM on 21 June 2010
        Measuring Earth's energy imbalance
        Thanks for the pointer Moldyfox. Abstract: It is essential to maintain global measurements of the earth radiation budget (ERB) from space, the scattered solar and emitted thermal radiative fluxes leaving the planet. These are required for the purpose of validating current climate model predictions of the planet’s future response to anthropogenic greenhouse gas forcing. The measurement accuracy and calibration stability required to resolve the magnitude of model-suggested cloud–climate feedbacks on the ERB have recently been estimated. The suggestion is for ERB data to strive for a calibration stability of ±0.3% decade−1 for scattered solar, ±0.5% decade−1 for emitted thermal, and an overall absolute accuracy of 1 W m−2. The Clouds and the Earth’s Radiant Energy System (CERES) is currently the only satellite program to make global ERB measurements, beginning in January 1998. However, the new climate calibration standards are beyond those originally specified by the NASA CERES program for its edition 2 data release. Furthermore, the CERES instrument optics have been discovered to undergo substantial in-flight degradation because of contaminant issues. This is not directly detectable by using established calibration methods. Hence, user-applied revisions for edition 2 shortwave (SW) data were derived to compensate for this effect, which is described as “spectral darkening.” Also, an entirely new in-flight calibration protocol has been developed for CERES that uses deep convective cloud albedo as a primary solar wavelength stability metric. This is then combined with a sophisticated contamination mobilization/polymerization model. The intention is to assign spectral coloration to any optical degradation occurring to the different CERES Earth observing telescopes. This paper quantifies the stability of revised edition 2 data. It also calculates stability, which the new protocols could give CERES measurements if used. The conclusion is that the edition 2 revisions restore the originally specified stability of CERES SW data. It is also determined that the climate calibration stability goals are reachable by using the new in-flight methodologies presented in this paper. However, this will require datasets of longer than approximately 10 yr. It will also require obtaining regular raster scans of the Moon by all operational CERES instruments.
116844. johnd at 11:21 AM on 21 June 2010
        Watts it like at a climate skeptic speakers event?
        Ian Forrester at 10:53 AM, read the study carefully. On page 1 you'll find information about planting and harvesting times relevant to the site of the trial. I guess you are thinking of regions where bitterly cold winters are the norm. Cropping in Australia is done in more temperate zones, as was the trial, so that should be taken into account.
116845. johnd at 11:10 AM on 21 June 2010
        Watts it like at a climate skeptic speakers event?
        Marcus at 10:16 AM, Marcus, read the study again, carefully. The part you cherrypicked was from another study referenced by the FACE article, "Seneweera et al2005 Journal of Crop Improvement 13-31-52" and arrived at by modelling. Any evidence of acclimation in the Horsham trials was due more to differences in varieties of cultivars as noted in the summary. If you examine the overall results over the 3 years FACE trials, such responses were limited to certain varieties, and these results, as indicated, will provide data to allow realistic modelling to occur. In any event, the response as depicted from the referenced study to elevated CO2 levelled off at the higher levels and did not return to lower levels as exhibited at ambient CO2 levels. This is nothing new, trials both under laboratory and real world conditions has found that optimum growth for many plants is achieved at levels of about 1200ppm CO2 and such levels have been used for many years already to produce some of the food that you may find in your local supermarkets and on your own table. Fortunately the scientists involved in the trials and with the Victorian DPI are more optimistic than yourself about the findings of the trials, and no doubt, will continue their work on improving production as they have done virtually since cropping has been part of the landscape in Victoria.
116846. Marcus at 11:05 AM on 21 June 2010
        How Jo Nova doesn't get the CO2 lag
        My understanding of the reason why there hasn't been a runaway warming event in the past 72 million years is because the pool of available CO2 has been that present in the total biosphere during that entire period (around 280-300ppm). That is to say, even at the height of every past interglacial, the maximum concentration of CO2 in the atmosphere has been less than 300ppm. The combined warming caused by both increased insolation & the natural peak in CO2, in the past has apparently not been sufficient to cause the release of methane hydrate in the Arctic regions. Unfortunately, humans are currently releasing levels of CO2 far above those naturally available in the biosphere-because we're burning CO2 sinks that were buried close to half a *billion* years ago, when CO2 levels were 10 times higher than today, & when the average temperature of the planet was around 6 degrees warmer than now. We are also releasing this CO2 at a rate far, far higher than usually occurs in nature (around 60+ years, compared to over 800 years), which is causing a rate of warming (in degrees per decade) far greater than what we've seen in the past. To the best of my knowledge, these are the reasons why we risk runaway climate change now, but never faced a similar threat in the past!
116847. Ian Forrester at 10:53 AM on 21 June 2010
        Watts it like at a climate skeptic speakers event?
        JohnD do you understand what photosynthesis is? Energy from sunlight is captured by the plant and converted into chemical energy (mostly carbohydrates in cereals). If you try and grow your plants earlier in the year you have far less sunlight, both duration and intensity, so that would reduce, not increase, energy capture. Also, winter wheat does not grow in the winter, it is planted in early fall, germinates and then goes dormant until the warmth of spring. Your arguments are as baseless as those put forward by other deniers that agriculture will simple move north (poleward) due to higher temperatures, ignoring of course that it is not temperature which limits agriculture but the availability of adequate soils.
116848. Marcus at 10:48 AM on 21 June 2010
        Watts it like at a climate skeptic speakers event?
        Marty promulgates another myth of the fossil fuel industry, which is that greater energy use=greater prosperity. If you were to plot per capita energy use (in Megawatts/Capita) vs per Capita GDP, you'd see that there isn't a strong correlation between the two. In the majority of Western nations, the average household uses about 30%-50% more electricity than it needs, mostly due to inefficient appliances & poor house design/poor insulation. There is much the same situation going on in many commercial properties. Most commuters use 20% more fuel than they need to get to their destinations due to idling in peak hour traffic jams-largely down to a lack of adequate public transport, inadequate car-pooling & very poor peak-hour traffic planning. What this tells me is that, far from increasing prosperity, inefficient use of electricity & fuel is actually *decreasing* prosperity, as high energy & fuel bills leaves most families with less cash in their pockets for other necessities. So, in truth, improving efficiency of energy use will not only significantly reduce CO2 emissions, it will also leave people with more money in their pockets. Oh &, btw Marty-as far as I'm concerned anyone who tries to win the "skeptic" argument by claiming the other side is pushing for "dictatorships", "scientocracy", "eugenics" etc etc, has lost the argument already. If you can't rely on the *facts*, but have to resort to blatant scaremongering, then you're really wasting your time at a site like this!
116849. Ned at 10:28 AM on 21 June 2010
        How Jo Nova doesn't get the CO2 lag
        thingadonta, I really think you're striving to find an inconsistency that just doesn't exist. During the glacial/interglacial cycles, the primary forcing is changes in the latitudinal/temporal pattern of insolation. This forcing is then amplified by a series of positive feedbacks involving CO2, methane, ice-albedo, dust, etc. Today, the primary forcing is CO2, complemented to a lesser extent by CH4, N2O, halocarbons, etc. The same feedbacks operate. All of these are discussed by IPCC and are basic staples of the consensus model of climate change past, present, and future. If John Cook doesn't discuss them in the article at the top of the thread, it's because he's responding to someone else's argument that specifically involves CO2 ... so he focuses on CO2. If you doubt this, go ahead and type "methane" or whatever into the search box at the top left, and you'll find that all of these factors are discussed in detail on this site. For example, one link that pops up is CO2 is not the only driver of climate Hope this helps.
116850. Marcus at 10:16 AM on 21 June 2010
        Watts it like at a climate skeptic speakers event?
        Well when you read the FACE study properly, we find the outcomes of the study are not as bright as John D would have us believe. Basically my reading of the study suggests that a near doubling of CO2 concentrations-under *ideal* conditions-will generate a SHORT TERM increase in biomass of around 20%-30% in *WHEAT*. The study points out, however, that photosynthetic rates decrease over the long-term due to acclimation, which suggests that these increases in biomass cannot be sustained-especially in the face of shortages in water & increased temperatures (conditions which are already an increasing reality for farmers in Southern Australia). Of course, one of the key problems of a warming climate is increased senescence-not heat stress. Increased senescence means that plants will ripen *before* they reach full growth. This will lead to a reduction of biomass-most especially *seed* biomass, with potentially devastating consequences (especially when one considers the reduced uptake of nitrogen-& therefore reduced protein yields-under high CO2 conditions). Unfortunately, John D's claim that we can simply "change the planting times" reveals an astounding ignorance of how modern agriculture works. For starters, most agriculture is a year-long affair, with both winter & summer crops. Secondly, farmers don't just plant arbitrarily-they usually wait for the first good rains of the season before planting (usually around late Summer to mid Autumn for Winter crops, & late Winter to Mid-Spring for Summer Crops). Of course, with rainfalls declining & usually getting later in the year (South Australia has seen an average 1%/year decline in Autumn rainfall since the 1970's), the ability to plant crops during ideal growing times becomes ever more restricted. Of course, what I love is this general theme, from the likes of John D, that the whole of society must simply *adapt* its entire way of life to rising CO2 emissions *rather* than the fossil fuel industry should lose even a single dollar of their mega-profits. What industry in history has enjoyed so much demand for its ongoing protection-nay coddling-than oil & coal?

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