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David Horton at 16:32 PM on 21 June 2010How 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. -
Doug Bostrom at 16:06 PM on 21 June 2010Watts 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. -
Chris Colose at 15:40 PM on 21 June 2010How 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. -
scaddenp at 15:24 PM on 21 June 2010How 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. -
Philippe Chantreau at 15:16 PM on 21 June 2010Watts 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? -
thingadonta at 15:11 PM on 21 June 2010How 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. -
David Horton at 14:28 PM on 21 June 2010How 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. -
Marcus at 14:15 PM on 21 June 2010Watts 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! -
Marcus at 13:38 PM on 21 June 2010Watts 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! -
Chris Colose at 13:23 PM on 21 June 2010How 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. -
shawnhet at 12:54 PM on 21 June 2010Astronomical 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, :) -
johnd at 12:27 PM on 21 June 2010Watts 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. -
notcynical at 12:20 PM on 21 June 2010Andrew 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. -
Marcus at 12:12 PM on 21 June 2010Watts 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. -
Bern at 12:06 PM on 21 June 2010Watts 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.
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Marcus at 11:51 AM on 21 June 2010Watts 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! -
Marcus at 11:33 AM on 21 June 2010Watts 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! -
David Horton at 11:32 AM on 21 June 2010How Jo Nova doesn't get the CO2 lag
Nicely summarised Marcus. -
Doug Bostrom at 11:26 AM on 21 June 2010Measuring 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. -
johnd at 11:21 AM on 21 June 2010Watts 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. -
johnd at 11:10 AM on 21 June 2010Watts 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. -
Marcus at 11:05 AM on 21 June 2010How 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! -
Ian Forrester at 10:53 AM on 21 June 2010Watts 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. -
Marcus at 10:48 AM on 21 June 2010Watts 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! -
Ned at 10:28 AM on 21 June 2010How 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. -
Marcus at 10:16 AM on 21 June 2010Watts 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? -
Ned at 10:16 AM on 21 June 2010How Jo Nova doesn't get the CO2 lag
MattJ: Just to pile on, in addition to the comments by Tom Dayton and Jim Eager ... as John Cook mentioned at the top of this thread, there are some graphs showing runaway and non-runaway positive feedbacks in a comment here. In all fairness, I have seen lots of people who are under the impression that any positive feedback in the climate system would inherently imply runaway warming, a la Venus. That's not actually the case, however. As long as the feedback factor is small enough, it will just amplify the original warming (or cooling). -
DrTom at 09:44 AM on 21 June 2010How Jo Nova doesn't get the CO2 lag
Cynicus, #6. Aloha. Yes, I will take those numbers for the sale of argument. Hot Methane escaping under pressure won't form clathrate unless it is contained at depth. Some will certainly dissolve to form anoxic zones but most will bubble up and enter the atmosphere. Methane is considered ~25 times stronger than CO2 as a greenhouse gas over a 100 year time frame; but over 20 years it's GWP is 72 and over 8 years a large release should have a noticeable effect, possibly in the form of a rapid-onset extinction event. Given the short-term 72-to-1 greenhouse potential of CH4 to CO2, we can guesstimate that within a short period of time we will have tossed the equivalent of an extra year of CO2 into the atmosphere from the Gulf and it will persist for 8 years. If it raises the average global temperature by just ONE degree...it will be one degree too much. ~IF~ we are near the terminal limits of global climate change, whether it is Anthropogenic or simply nature's way of telling us we have exceeded our 'use by' date, we should have a definitive, quantifiable indication within the next eight years. -
kdkd at 09:41 AM on 21 June 2010How climate skeptics mislead
Doug #222 Indeed, the Bayseian technique (and the related but simpler Akaike information criterion) is a much better way of assessing hypotheses, than the standard hypothetico-deductive model. Especially for systems which have compleity, or where proper experiments can't be performed. -
moldyfox at 09:35 AM on 21 June 2010The albedo effect
NASA showed that even with a radiometer on the Moon, you could not come close to measuring the Earths global climate due to lack of coverage. Earthshine (science et al) is a globally discredited paper and should not be used by any climatologist trying to detect 0.3%/decade albedo and 0.5%/decade cloud climate feedback effects. On the other hand review 2009 G. Matthews, “In-flight Spectral Characterization and Calibration Stability Estimates for the Clouds and the Earth’s Radiant Energy System” Journal of Atmospheric and Oceanic Technology. Vol 26, Issue 9, pp 1685-1716. This explains how existing CERES data has significant calibration drifts (also which are correctable). Initial analysis shows corrected CERES data would show a slightly reducing albedo from 2000-2007 and a slightly increasing outgoing long wave. Read the paper and assess it yourself. -
thingadonta at 09:28 AM on 21 June 2010How Jo Nova doesn't get the CO2 lag
As usual you have left out the detail to create an inconsistent argument. AGW proponents claim that current warming will/is releasing methane from arctic areas to warm the Earth. If so, this must also occur at the end of Ice Ages, but it is never mentioned, so as not to get in the way of the 'c02 explanation' for the end of Ice Ages. Methane release must occur as the sun has warmed the earth since 1750-1950+, which is also conveniently not mentioned, so as to not get in the way of the c02 warming effect of the late 20th century. Also, the warmign oceans at the end of ice ages must store all that 'missing ocean heat', which is then slowly released, as AGW proponents claim it will do over the coming century. You also have ice albedo changes as Ice ages end, vegetation changes, and ocean current changes. All of these are not mentioned in the above article, so as to bolster the effects of C02, but they are usually mentioned whenever AGW proponents want to enhance projected T effects over the next century. Inconsistency anyone? -
moldyfox at 09:26 AM on 21 June 2010Measuring Earth's energy imbalance
The truth is out there CERES solar calibration was done using a reference radiometer on the ground, with 13 year old mirrors that were never measured, see peer reviewed 2009 G. Matthews, “In-flight Spectral Characterization and Calibration Stability Estimates for the Clouds and the Earth’s Radiant Energy System” Journal of Atmospheric and Oceanic Technology. Vol 26, Issue 9, pp 1685-1716. The climate records can be fixed and the imbalance is easily explainable by the paper given that the reference standard was never actually measured. Read it and assess for yourself. -
moldyfox at 09:19 AM on 21 June 2010How we know global warming is still happening
The truth is out there, before drawing conclusions on CERES I suggest you read 2009 G. Matthews, “In-flight Spectral Characterization and Calibration Stability Estimates for the Clouds and the Earth’s Radiant Energy System” Journal of Atmospheric and Oceanic Technology. Vol 26, Issue 9, pp 1685-1716. Be critical, I cannot fault it, and it explains CERES data currently contains significant calibration drifts so no climatologist should base any conclusions on it (plus its solar wavelength calibration is based on a 13 year old ground radiometer which has not been measured itself). In truth the albedo dropped slightly from 2000 to 2007, the outgoing long wave slightly increased. This agrees with models used by Trenberth etc. Read it and assess for yourself. -
MattJ at 09:13 AM on 21 June 2010Watts it like at a climate skeptic speakers event?
Reply to tobyjoyce #24: What? "politicians have little choice but to follow the scientific consensus?" But this claim is itself unscientific, and very much so. Politicians VERY rarely even pay attention to the consensus. Especially today's politicians, who have one ear tuned to the lobbyists, and the deafer ear turned to the polls. Have you really forgotten already how under Bush, the EPA turned a blind eye to all the scientific evidence, not only for AGW, but for the need for lower emission limits for a great many other pollutants as well? People were even fired for pointing out the need based on peer-reviewed scientific results. This trend was particularly bad under Bush, but it was not unique to his mis-reign. On the contrary: ignoring the real science is situation normal for politicians. It takes a concerted effort to get them to pay attention to it, an effort that is only occasionally successful. -
moldyfox at 09:08 AM on 21 June 2010It's albedo
The truth is out there Recent peer review of CERES in-flight calibration show that the CERES solar wavelength response drops in RAPs mode due to exposure to atomic oxygen. The data you show above was corrected using the rev 1 corrections described in 2009 G. Matthews, “In-flight Spectral Characterization and Calibration Stability Estimates for the Clouds and the Earth’s Radiant Energy System” Journal of Atmospheric and Oceanic Technology. Vol 26, Issue 9, pp 1685-1716. This also explains how those corrections did not account for the dimming of the on board lamps and hence over-corrected. CERES data properly calibrated would therefore show a slight drop in albedo from 2000 to 2007 as well as an increase in outgoing long wave flux (as Trenberth's climate models would expect). Read the paper and be critical, I could not fault it... -
Jim Eager at 08:51 AM on 21 June 2010How Jo Nova doesn't get the CO2 lag
MattJ, add the series 1.0, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1. Does it lead to a runaway value? -
marty at 08:20 AM on 21 June 2010Watts it like at a climate skeptic speakers event?
Sorry you beat me to it with comment 56. In response to which I would say that I agree that consumer society is an alienated affair of massaged desires offered as substitutes to real freedom. However we cannot reject the whole thing because we have seen massive technological development. And besides that's the nature of the society we live in. People enjoy their mobility and I like living in a global age. Obviously wastefulness is inefficient and anything that can increase efficiency seems like it's probably a good thing, but that doesn't mean that people can't have a new T.V. set. The way that things are going they will be virtually dematerialised in a few years anyway. Trying to keep this to the general topic of opening up the debate however I would say that low-carbon can be high-tech. There are also interesting low-tech options that needn't be seen as conservative or new-age or anti-progress. I'm quite excited by the idea of rammed -earth building for example, not because I'm particularly convinced by the AGW argument but just because it's an interesting idea. If the AGW hypothesis is indeed correct then we need to have a much more open approach to what we are going to do about it. -
Tom Dayton at 08:18 AM on 21 June 2010How Jo Nova doesn't get the CO2 lag
MattJ, you can create a spreadsheet containing positive feedback that does not run away. See my comment on another thread. -
Riccardo at 08:12 AM on 21 June 2010IPCC were wrong about Amazon rainforests
Just for info, the Sunday Times retracted his piece by Jonathan Leake. RealClimate has the story. -
MattJ at 08:04 AM on 21 June 2010How Jo Nova doesn't get the CO2 lag
The comment in the article, "A common misconception is that positive feedback always means runaway warming. This isn't necessarily the case. If the feedback is not too great, what happens is an amplification of initial warming with the temperatures eventually stabilising at a higher level." sounds misleading at best. Now I have to admit that my own memories of positive feedback in electronics circuits is somewhat vague, but what I recall is: in-phase positive feedback DOES cause unlimited growth, which is exactly why the circuit designer tunes the feedback loop to limit the gain/oscillation to a useful value. This is done in one of two ways 1) adjust the phase of the feedback or 2) decrease the gain of the positive feedback as the circuit output approaches the desired value. Which one of these is the best analogue for what happens with positive feedback in climate? In particular, I wonder in the citation above: once it "stabilizes at a higher level" is the feedback even still positive? Isn't it changing throughout that time, stabilizing only when the feedback drops, so that it is no longer 'positive'? -
Doug Bostrom at 07:53 AM on 21 June 2010Watts it like at a climate skeptic speakers event?
Marty, as others have said the science portion of this issue is not going to be settled in pubic debate. If you want to assess the "state of the science" and you're leery of the IPCC, see the recent National Academy report Advancing the Science of Climate Change, commissioned by Pres. Bush. You can read the NAS report here, online. (Just scroll down to see the freely readable version) As to your distaste for "green" solutions, don't overgeneralize. I for one would prefer using the ample fusion power sleeting down on us but short of a miracle of concerted effort I don't see us making that choice fast enough to swerve our depletion of fossil fuels away from the double disaster of resource exhaustion and serious lingering damage to our little skin of atmosphere. We'll end up with a messy and substantially inadequate combination of technologies, some archaic and anachronistic, some better, not enough to produce an optimum outcome. -
marty at 07:41 AM on 21 June 2010Watts it like at a climate skeptic speakers event?
I don't really know what I think about the science, since as I said in my original post I've not had the benefit of a full public debate. I read the stuff from this site and I read the stuff from the sceptic side and I am simply not qualified to be able to decide. What would have been of help here is a debate among the experts from both sides where I can see who seems to make the most sense. But you are right in that even were I to become convinced of the case for AGW I don't think that the science translates straight into public policy. For one there is a great deal more potential impact on peoples lives being touted here than a vaccination program requires. Also it seems that there is an automatic assumption that the science translates straight into a green agenda, rather than say a develop our way out of it agenda that might include nuclear power for example, or hydro-electric dams and so forth. I think the idea of solar, wind, wave power etc is great but it seems to me that we need to provide for increased energy demands come what may to allow for economic expansion and social progress. I think that we have to look at all the alternatives here and not be too blinkered. That's basically the point that I'm making. If those convinced of AGW want to have a progressive rather than conservative impact on the world then I think that the debate needs opening up and not closing down with glib putdowns like Mythago's 'go and eat banknotes', response to my concerns about how the science meshes in with the economic realities. -
Doug Bostrom at 07:31 AM on 21 June 2010Astronomical cycles
I've had fun rummaging through Scafetta's citations, Riccardo. Indeed he does seem obsessed, makes a perilous leap from tentative indications to firm conclusions, indulging in rhetoric along the way. I suppose in way that's good; I dug into the citations because Scafetta's remarks about the IPCC report are factually wrong and led me to wonder what else he was misinterpreting or exaggerating . -
Riccardo at 07:16 AM on 21 June 2010Astronomical cycles
shawnhet, 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. doug_bostrom, several scientists are currently looking at possible sources of decadal variability. I think that the work on the cycles could be valuable in this respect, but his sort of obsession to disprove AGW led him off road. -
Doug Bostrom at 07:11 AM on 21 June 2010Watts it like at a climate skeptic speakers event?
Marty, I'm not sure that access to sufficient food to eat, reliable shelter, education and health care automatically entails "massive industrialization." These things are found together, true, but in fact ample access to ever larger and more numerous televisions, an automobile for every 2 persons, hundreds of square feet of largely unoccupied domestic living space etc. per capita etc. are not really prerequisites for a happy and health life. In fact, such irrational choices could be said to retard improvement of the fundamental human condition. -
Doug Bostrom at 07:03 AM on 21 June 2010Watts it like at a climate skeptic speakers event?
Marty, would it be safe to say you don't have a problem with the science per se but rather the indications and clues it offers as regards the future direction of the human experience? -
johnd at 07:02 AM on 21 June 2010Watts it like at a climate skeptic speakers event?
Ian Forrester at 00:47 AM and Jim Eager at 04:31 AM. That same response to heat stress has always been the case as long as wheat has been grown. Unless you see the annual cycle of the seasons disappearing completely, the answer to avoiding heat stress would simply mean sowing earlier, rather than later as they did in the trials. Ongoing research into developing improved cultivars that perform better in cooler and wetter conditions, the winter wheats, has been progressing for several decades. -
Sean A at 06:52 AM on 21 June 2010How Jo Nova doesn't get the CO2 lag
Gallopingcamel, which of these points are problematic? 1) Orbital changes cause a slight warming. 2) This slight warming causes a little bit of CO2 to be released from the oceans, over hundreds of years. It takes about 800 years for the waters in the ocean to overturn. 3) Increased CO2 in the atmosphere leads to more warming. 4) Warming promotes evaporation and starts to melt ice sheets; increased water vapor and reduced albedo amplify the warming. 5) More warming leads to more CO2 being released from the oceans. We've got positive feedbacks now. Go to #3. 6) Eventually a new climate equilibrium is reached. In short, Milankovitch cycles start the warming, which eventually releases CO2 from the oceans (the 800 year lag), which leads to more warming, which in turn releases more CO2. The whole process takes thousands of years. See The 800 year lag in CO2 and What does the lag of CO2 behind temperature in ice cores tell us about global warming? Note that "CO2 does not initiate the warmings, but acts as an amplifier once they are underway". How is any of this the least bit controversial? Which parts, specifically, do you disagree with? -
marty at 06:51 AM on 21 June 2010Watts it like at a climate skeptic speakers event?
It's quite true that population growth tends to fall naturally but not directly for the reasons you give since you miss out the most important factor - prosperity. Unfortunately in the developing world poverty means that birthrates remain high. I personally find the equating of human lives and carbon a thoroughly abhorrent idea - see in my original post regarding the Malthusian conclusions drawn from the science. However, if you were to make such comparisons, and if you were to seek to reduce population growth in order to reduce carbon emissions then it might be argued that we need a massive industrialisation and development in the developing world as the solution to global warming. -
Doug Bostrom at 06:38 AM on 21 June 2010Astronomical cycles
Is it ironic that Scafetta's hypothetical but unexplained connection between climate and Earth-external ~60 year periodic forcings appears to hinge largely on acceptance of Mann et al's dendrochronology interpretations? See Scafetta's key cite of Long-period Cycles of the Sun's Activity Recorded In Direct Solar Data and Proxies (MG Ogurtsov, YA Nagovitsyn, GE Kocharov, H Jungner - Solar Physics 2002, full-text PDF) If Scafetta had confined himself to making this a review paper and eschewed forming conclusions about actual percentages of attribution it would have been a lot better.
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