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Gilles at 18:41 PM on 18 April 2011Christy Crock #3: Internal Variability
DM : you don't understand what I'm saying. I'm not saying that all models present a significative drift. I said that many models have presented such drifts, that this has always been considered as a problem when it happened, so that models have evolved to avoid these drifts. You are saying that "models improved" - I'm just saying that the "improvement" has been quantified by an absence of drifts - and that the goal has been to AVOID them or correct them when they happen. don't you understand that this is quite like a darwinian selection, insuring that models converge towards an absence of drift ? and allowing to say at the end, triumphally : "look, we don't have any long term drift anymore without anthropogenic forcing" ? -
villabolo at 18:37 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
@78 Gilles: "Villabolo "For one who is very much into quantifying things to death," I like very much this one. You're right, beliefs are much easier when we don't care about quantifying. But sorry, I'm an annoying scientist, you know, the kind of those who wanted to know precisely what the orbit of Mars really is - who cares, actually ?" I care Gilles. That's why it's nice to quote people in full context and show the rest of the sentence that has been cut off in mid stream. Please notice the comma left hanging at the end of my sentence you quoted. Just for your information, when one quotes a partial sentence, something known as an ellipsis is placed after the end of that sentence in order to inform the reader that he is not reading the entire sentence. An ellipsis, in case you're wondering, looks like this ... Since I care about the question that followed my amputated sentence let me restate it by quoting my own post. Please notice the ellipsis. "For one who is very much into quantifying things to death, let me ask you, Gilles; what level of CO2 increase can be tolerated by plants until a point is reached that noticeably effects them?... Besides, do you know the levels of CO2 that where used in the experiments which gave the dramatic results? They are likely to be much higher than our current C2 levels." It would have been nice if you had answered my question but that's all right. It's gotten a bit stale. However, we can discuss Mars' orbital mechanics as soon as someone claims it affects Earth's climate.Moderator Response: [Dikran Marsupial] Please can you reduce the use of bold tags, it is equivalent to the all caps "shouting" that is against the comments policy. -
JMurphy at 18:36 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
To add to Bibliovermis's comments on Arkadiusz Semczyszak's link, some information from the paper itself : The PETM is associated with a large negative carbon isotope excursion recorded in carbonate and organic materials, reflecting a massive release of 13C-depleted carbon (4, 5), an ~5°C increase in mean global temperature in ~10,000 to 20,000 years (1), a rapid and transient northward migration of plants in North America (6), and a mammalian turnover in North America and Europe (7). Higher precipitation amounts could have been as important as high CO2. As already stated, it's a long time-period compared to now and higher precipitation may have been just as important. Also, I wonder how easily all those plants are going to migrate (and where to ?), and how we'll feel about a similar "mammalian turnover". -
Arkadiusz Semczyszak at 18:35 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
On this page, is briefly described the global food market.: “Food production more than doubled (an increase of over 160%) from 1961 to 2003. Over this period, production of cereals—the major energy component of human diets—has increased almost two and a half times, beef and sheep production increased by 40%, pork production by nearly 60%, and poultry production doubled.” -
Arkadiusz Semczyszak at 18:33 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
“To explain the observations, the carbon must have been released over at most 500 years.” -
ranyl at 18:32 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
The PETM tropical data above is all from one area in Northern South America and it got wetter and hotter by 3C but not into the critical region above 35c where tropical vegetation starts to becoem heat stressed. Considering that the ITCZ moves north when the NH warms (which it would with a burst of CO2 due to the NH greater land mass) this results are probably predictable and say nothing about the southern regions of Amazon. Also on the land sink it seems everyone seems ot forgetting that our land sink in the last 40 years has be greatly increased by artifical fertilization and the extra reactive nitrogen artifically boosting growth everywhere but also killing biodiversity everywhere so we have to stop using it loads and so by by land sink! -
Gilles at 18:32 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
(closing tag added) Marcus : correlation is not a proof of causation, but absence of correlation (or even negative correlation) is still worse ! and I don't see any hint that the increase of CO2 has made the yield of crops decrease in the world- since it has simply not decreased. I have no idea what beetles like, and maybe the defenses of the particular species they studied are weakened by more CO2 - but they don't give the final result on the total yield (do the damages made by beetles offset the increased yield or not ?), and of course there is nothing like a global estimate at a worldwide scale. Again, adding a set of cherry picked drawbacks doesn't say anything on the final result - with this method you can demonstrate what you want. -
Dikran Marsupial at 18:31 PM on 18 April 2011Christy Crock #3: Internal Variability
Giles@95 Modern GCMs, have not included flux adjustments for a very long time. If you read the Wikipedia article rather than quote mining, you will see that they are talking about the 2001 TAR, which means they are talking about models in use over a decade ago. Things have moved on significantly from there. The really funny thing though, is that if you actually read the page in the report you linked to in message 96, you will find that it says (bear in mind it was published in 2005, so they are talking about models of late 1990 to early 2000 vintage): "Until recently [DM emphasis mine], it has been necessary to used so-called flux adjustments (or "flux corrections", Sausen et al 1987) to prevent drift in the climate of the coupled system that arises from the inadequacies in the component modules and in the simulated fluxes at their interfaces" You do know what "Until recently" means don't you Gilles? Also if you read the rest of that paragraph, you will find that were the flux adjustments were still being used in the early 2000s, the corrections had been getting smaller as the models improved, and that the IPCC had found no systematic bias in the climate variability between models where the flux adjustments were used and where they were not and that both types of models are useful for attribution studies. Your own source suggests that drifts are correctable and do not pose a problem. You have made a fool out of yourself by your quote mining. Next time see if the material is (i) up to date and (ii) actually does support your assertions. -
chek at 18:21 PM on 18 April 2011Muller Misinformation #3: Al Gore and polar bears
Presumably, as it's the latest in political fashions, Muller's remarks were not intended to be taken as "factually accurate". Together with the ( -snip- ) Watts as UHI "hero" compliment, that's two strikes down so far.Moderator Response: [DB] Inflammatory term snipped. -
Bibliovermis at 18:16 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
"Rapid" is in geologic terms, and in the case of the PETM means ~20,000 years. The PETM was the cause of a global mass extinction event. That temperature change over 20,000 years is a viable likelihood in a matter of centuries in an unabated business-as-usual scenario. -
Arkadiusz Semczyszak at 18:14 PM on 18 April 2011Solar Hockey Stick
For Dana1981 - who likes “simple calculations”. The Sun - current solar “hockey stick” - what does this mean for the present warming? We know already - with my comment above (63) and Berenyi Péter (75), that the The sun - to change its activity - it works on the climate of delay - “lag”. Thus, TSI decline after 1985 is no argument that this “is not The sun”. Well, but for example, Lockwood - indeed - cites: “... the current grand maximum has already lasted for an unusually long time ...”. Despite this adds: “However, the popular idea (at least on the Internet and in some parts of the media) that solar changes are some kind of alternative to GHG forcing in explaining the rise in surface temperatures has no credibility with almost all climate scientists.” Why? “In other words, the feedback must essentially double the GHG forcing if they are the cause of the GMAST rise. On the other hand, our best estimate of the first term on the right-hand side of equation (10.1) is 0.23 W m−2 (ΔITS=1.3 W m−2). If the analysis of Scafetta (2009) were correct and 65 per cent of the observed warming were due to solar effects, then the first term on the right-hand side of equation (10.1) plus the feedback would need to supply 0.65×5.15=3.35 W m−2. In this case, the feedback must supply 3.35−0.23=3.12 W m−2, which means that they need to explain an amplification of the solar input by a factor of 13.5.” Full agreement. However, as it was before? The like changes in temperature - as now - most probably, we observed in the Holocene (especially the middle Holocene), the above-defined variability of the Sun. At least once in the Holocene (perhaps several times), comparable to the "... solar input by a factor of 13.5. ... "certainly has been achieved! Connection - allegedly our GHG - and react to changes in the TSI for temperature changes in the Holocene, gives absurd results. professor Shaviv: “According to the IPCC (AR4), the solar irradiance is responsible for a net radiative forcing increase between the Maunder Minimum and today of 0.12 W/m 2 (0.06 to 0.60 at 90% confidence). We know however that the Maunder minimum was about 1°C colder ...”, “This requires a global sensitivity of 1.0/0.12°C/(W/m 2 ). Since doubling the CO 2 is thought to induce a 3.8 W/m 2 change in the radiative forcing, irradiance/climate correlations require a CO 2 doubling temperature of ΔT x2 ~ 31°C !!” Well, unless we accept the data - changes in TSI - from this analysis: Jeffrey A. Glassman, PhD, However, the balance of feedback for a doubling of CO2 would be only slightly positive or even negative. It is true that a simple calculation? Of course, the only alternative is a combination of solar and GHG (as one of the effects of second-order) to explain the change in temperature in the mid-Holocene or MCA / LIA. Frank et al., 2010.: “ ... a 50-year CO2 response lag—such timing is consistent with modelled CO2 response to a temperature step change. [for pre-industrial 1050–1800 period]” The temperature is delayed to the sun - an increase in TSI. Changes p.CO2 delayed against temperature. According to ice cores, however, changes in CO2 in this period were small (c. 10 ppmv). Nevertheless, the effect of Sun + CO2 (+ other "second-order effects") - similar to today! How? Something does “not fit” in these "simple calculations" ... The concentration of CO2 in the atmosphere - especially his change - had to be bigger than it used to show the cores. I would suggest to "throw away" data by ice core CO2 (and those by cores from the bottom of the ocean - as well). I propose to also adopt the proposed by me - many times here - the deep ocean CO2 + higher sensitivity of soil (respiration) on temperature ... I recall the most recent reference is apropos of the latter: Suseela et al., 2010.: “Soil respiration is the largest flux of carbon dioxide to the atmosphere, releasing more [several times - 98 +/- 12 PgC / 8-9 Pg C ] carbon than fossil fuel combustion.” “... even a small warming-induced increase in carbon dioxide emission from soils could act as a positive feedback to climate change.” Karhu et al. 2010.: “Compared to the method used for current global estimates (temperature sensitivity of all SOC equal to that of the total heterotrophic soil respiration), the soils studied will lose 30-45% more carbon in response to climate warming ...” Dorrepaal et al., 2009.: “Climate warming therefore accelerates respiration of the extensive, subsurface carbon reservoirs in peatlands to a much larger extent than was previously thought ...” The steady increase in "strength "of the sun for a long time = constant small increase in temperature = increase in soil respiration + deep ocean - for example by upwelling = 80-90% current rise in CO2 + other effects of second order = continued increase in the temperature ... The stronger the sun is the increase in volcanic activity - a decrease of ozone in the stratosphere - the reduction in marine algae (possibly caused also by warming) - the increase in frequency of El Nino - another feedback causing a natural increase in CO2 ... -
Dikran Marsupial at 18:08 PM on 18 April 2011Christy Crock #3: Internal Variability
Giles@94 Blatant trolling again, if you knew what you were talking about you would know when they needed to correct them. You have no evidence that any of the models actually were corrected, just that there was a suggestion from the organisers of the project that a control run were made for those models where it was thought it might be necessary so that any drift could be corrected if required, and you are presenting it as if that implied that the models actually did exhibit a drift. I was merely applying the same sort of pedantry to your arguments that you have used on virtually every thread to which you have "contributed". Now, if you have a reliable source e.g. a peer-reviewed paper that shows that these drifts are actually a problem, then lets see it. It is time to "Put up, or shut up". -
villabolo at 18:05 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
@65 LukeW: Luke, I didn't have a chnce to respond to all of your points in post #75 but I can't believe I missed this one (!?) "In fact given the IPO change - expect a cracker decade for Australian rainfall ahead - more Las Ninas and stronger ones. Boom time for producers?"
??????????????????????????????????????????????????
Are you aware of what those rains did to Australia recently? Of course, even if it had not downgraded a sizeable portion of the wheat crop to animal feed status, look at the wonders it has done for Australia in general. Like flooding an area the size of Texas.
John Cook would be pleased.
And you want those La Ninas to get stronger?
It looks like it's going to be a boom time for the rowboat industry.
Moderator Response: [Dikran Marsupial] tags fixed (hopefully correctly). -
Gilles at 18:04 PM on 18 April 2011Christy Crock #3: Internal Variability
other example : http://books.google.fr/books?id=52zXIwAUVa8C&pg=PA105&lpg=PA105&dq=drift+climate+simulation&source=bl&ots=TmfA5d7tCl&sig=UwM6f2N-Xd7l-vRw5LPFLUfwK9Q&hl=fr&ei=u-6rTez5G5SChQf8l4DOCQ&sa=X&oi=book_result&ct=result&resnum=3&ved=0CC0Q6AEwAg#v=onepage&q=drift%20climate%20simulation&f=false clearly enough, drift has always been a problem and models have evolved to avoid the drifts meaning that there has been a selection bias leading computer scientist to favor models with low drifts as the "best ones". I don't think you can reasonably deny that.Moderator Response: [muoncounter] Please do not use search text in place of actual citation. -
Gilles at 18:01 PM on 18 April 2011Christy Crock #3: Internal Variability
http://en.wikipedia.org/wiki/Global_climate_model "Many of the non-flux adjusted models suffered from unrealistic climate drift up to about 1°C/century in global mean surface temperature." so my question is : when you use "flux adjusted" models, what do you adjust and how ? -
Gilles at 17:56 PM on 18 April 2011Christy Crock #3: Internal Variability
sorry but what you say is quite unclear : what does "may be corrected" mean ? - when do we need to correct them ? note that a drift cannot be indefinite since it would lead eventually to unreasonable high temperatures - so it can only be a part of a very long oscillation - much longer than the duration of the run. It is a "drift" just because our capabilities of computation do not allow to compute a long enough time to see the oscillation - do you agree with that ? -
Arkadiusz Semczyszak at 17:53 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
Effects of Rapid Global Warming at the Paleocene-Eocene Boundary on Neotropical Vegetation, Jaramillo et al. (28 coauthors !), 2010.: “We observed a rapid and distinct increase in plant diversity and origination rates, with a set of new taxa, mostly angiosperms, added to the existing stock of low-diversity Paleocene flora.“ “The tropical rainforest was able to persist under elevated temperatures and high levels of atmospheric carbon dioxide, in contrast to speculations that tropical ecosystems were severely compromised by heat stress.” So as can see the above post still is just speculation ... -
chris1204 at 17:45 PM on 18 April 2011Muller Misinformation #3: Al Gore and polar bears
Thank you Albatross :-) CBD: And vast areas about which we have inadequate data coupled with three contiguous areas, one growing and two stable. The populations here are not modest. It's important to consider why one area is actually growing not for the purposes of point scoring but to work out if we're doing something right somewhere. More intriguing, why don't we have enough data about Fern Basin given the wealth of data for the rest of Canada? -
Marcus at 17:30 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
So I guess the point is that-*maybe* increased carbohydrate in soybean leaves in making them more attractive to these beetles (the researchers were pretty vague on whether this was, in fact, the case) but the *real* problem is that the plant has a far reduced ability to defend itself from these attacks-meaning that the beetles will be able to breed & feast more effectively. Hardly a *positive* for agriculture. -
Marcus at 17:25 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
BTW, Gilles-as a "scientist", wouldn't it be a good idea to *read* an article before commenting on it? I draw your attention to the following comments: "the team allowed beetles to live out their lives in one of three conditions: on a high CO2 plant, on a low CO2 plant outside the Soy FACE plot, or on a low CO2 plant grown outside the test plot but which had its sugar content artificially boosted." Now what they found was that *only* the bugs feeding on the high CO2 plant were seeing an extended lifespan & greater breeding times-& this had nothing to do with sugar load, & *everything* to do with changes in plant hormone levels-hormones which are a key to the plants defenses against insect attack. Please *read* the article, properly, before you embarrass yourself further. -
Marcus at 17:18 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
"I prefer eating big and sweet fruit than small and acid ones." Again, increased CO2 tends to lead to an increase in *vegetative* growth at the expense of reproductive biomass-including seeds & fruit. So again your correlation doesn't really hold up to the available evidence from other sources about the negative impacts of raised CO2. -
Marcus at 17:15 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
"my own common sense tells me that I should first start with first order correlations and then look at more complex issues if necessary." Your problem though, Gilles, is that you consistently mistake correlation with *causation*-even when there is no underlying justification for it. As to the soybean issue-its already been established that a combination of higher CO2 & higher temperatures results in a decrease in the nutrient content of many crop plants-& I doubt Soybean is exempt from this. Given that, its highly unlikely then that the insects are being attracted to the soybean plant by its higher nutrient content, but most likely due to its reduced defenses. -
Gilles at 17:09 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
Villabolo "For one who is very much into quantifying things to death," I like very much this one. You're right, beliefs are much easier when we don't care about quantifying. But sorry, I'm an annoying scientist, you know, the kind of those who wanted to know precisely what the orbit of Mars really is - who cares, actually ? concerning " common sense deductions based on the conclusions of science." , my own common sense tells me that I should first start with first order correlations and then look at more complex issues if necessary. An example : "Soybeans grown at elevated CO2 levels attract many more adult Japanese beetles than plants grown at current atmospheric carbon dioxide levels." Well, I can understand that beetles like more nutritive and may be richer plants. I would do the same - I prefer eating big and sweet fruit than small and acid ones. This doesn't prove that the overall effect is negative. And this a comparison experiment - meaning that probably beetles could choose between two different varieties. But if they had no choice, because every plant would grow in the same way, maybe they would be less concentrated on these plants. And they may be also adaption of plants to the new conditions, etc, etc... just selecting one effect and considering only its influence is far from giving the answer.Off topic comments removed -
Dikran Marsupial at 17:04 PM on 18 April 2011Video on why record-breaking snow doesn't mean global warming has stopped
Giles@23 wrote "so you mean that the falsifiable content of AGW theory is restricted to "the temperature will rise in the XXI century" No Gilles, I didn't say any such thing, you know it, I know it and anyone reading this thread also knows it. I said the IPCC report is full of falsifiable predictions, that temperatures will rise is only one of them. I had been giving you the benefit of the doubt, but that is just blatant trolling and you should be ashamed of yourself. -
Albatross at 17:03 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
No worries Villabolo. Along the same lines here is a correction to my post @71. I meant to say: "And if you doubt that droughts have a negligible impact on crops, then think carefully what happened in Russia last year, in Australian in 2007, in Europe in 2003, on the Canadian prairies in 2002. " -
villabolo at 16:38 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
@72 Albatross: Thank you for noticing my ongoing editing. -
villabolo at 16:32 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
@65 LukeW: You'll be happy to know that I removed the reference to increased fires as a result of increased vegetation. I have a feeling that it could happen; but it's impossible to predict in the long run how much of the earth's surface is going to be prone to fire versus how much is going to be resistant, or about the same. As far as the issue of tillage, I previously mentioned the superiority of Permaculture. Yet, I emphasized that time constraints due to a most likely "perfect storm" of events-AGW related-is going to bring on social instability. Adaptability is a matter of how fast things happen. Common sense tells us that the faster a negative event occurs, the less able we are in adapting to it. In my opinion, as I previously mentioned, our society is going to get destabilized to the point where it's not going to benefit from anything. That's not to say that a variety of alternative technologies and techniques will not be used; but they will be used by members of a fragmented and disintegrating society. I foresee a good chance of our evolving into a feudal state in a hundred years. The only silver lining I see in all of this is a sizeable drop in the use of fossil fuels due to major economic shrinkage or outright collapse. -
Alex C at 16:29 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
I wonder myself, since I am not familiar with this subject much, whether migration of vegetation will be hindered by Hadley Cells. There are latitudinal barriers that deal with precipitation too, not just temperature or land area. Does anyone have any input on the possible implications that such systems would have on the extent of vegetation migration? -
Gilles at 16:22 PM on 18 April 2011Video on why record-breaking snow doesn't mean global warming has stopped
so you mean that the falsifiable content of AGW theory is restricted to "the temperature will rise in the XXI century". I would buy it, since I do believe that CO2 is indeed a greenhouse gas and must contribute to some warming, and that generally it seems that even natural variability has ended a cold period in the XIX century and this is likely to last a little bit more. So it's more likely that temperature will increase that they would decrease anyway (even without CO2, I would think the same). Now this is a rather weak assertion, very far from "it will be a catastrophe for mankind and we must stop ASAP all use of FF to avoid it". Do you have any falsifiable test to support the latter assertion ? -
Marcus at 16:20 PM on 18 April 2011What was it like the last time CO2 levels were this high?
I know its OT, but am I the only one whose noticed that-the moment Gilles was required to remain On topic-he has had nothing further to add to the conversation? -
Dikran Marsupial at 15:53 PM on 18 April 2011Christy Crock #3: Internal Variability
Giles@92 That doesn't say there is unforced drift, just that for some models there may be a unforced drift that may be corrected using the control run. It does not say that this was was actually done. This is seems to me just an example of scientists taking a "belt and braces" approach and check these things to be sure. What you are doing is quote mining, not science. Go find a paper or source that shows this drift is actually a problem. IMHO trying to make something of an experiment having a control is a bit of an odd scientific attitude! -
owl905 at 15:48 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
The downside of CO2 increases is understated. Reread the comments, and notice how many of the pro-pollution arguments are questions, insinuations, and vacuous logic attempts. There has been no discernible, global, growth increase in a world that's charged CO2 levels by 40%. In opposition to the US East Coast study referenced by whitsend is the notorious growth-lapse that became part of Briffa's "hide-the-decline" scandal. To increase yields, no one has laid out CO2-delivery pipes similar to the FACE experiments - every fertilizer BUT CO2. Having CO2 airborne counts of 400ppm is a shrug compared to the 800-1600ppm in the damp soil where the roots are feeding. The FACE experiments long ago minimized the value of the increased GHG pollution: http://scienceblog.com/522/climate-surprise-high-co2-levels-can-retard-plant-growth/ Boosts are transitory: http://www.newscientist.com/article/dn11655-climate-myths-higher-cosub2sub-levels-will-boost-plant-growth-and-food-production.html Even when care was taken to measure the isolated effect, the net conclusion was bad - nutritional loss: 2005-Beijing http://www.scidev.net/en/news/rising-carbon-dioxide-could-make-crops-less-nutrit.html 2009-Germany http://www.newscientist.com/article/mg20327223.200-co2-makes-crops-less-nutritious.html ... and a side-order of increased toxicity: http://www.nicholas.duke.edu/thegreengrok/fertilizationeffect And none of that compares to the economic losses as extreme weather pattern changes destroy crops - most recently western Canada, Australia, and Russia. And it doesn't matter if crops would have grown well ... if only someone had planted them there. And that all pales in comparison to the stress placed on the bottom of the ocean's food chain - phytoplankton: http://www.usnews.com/science/articles/2010/01/14/co2-increase-in-our-oceans-may-stifle-phytoplankton Deny, diminish, and distract all you want, but there's going to be a huge cost in altering crops and natural vegetation around the globe - for centuries to come. -
Gilles at 15:44 PM on 18 April 2011Christy Crock #3: Internal Variability
DM#90 well for instance, look at this page http://www-pcmdi.llnl.gov/ipcc/standard_output.html and please explain me how you understand the experiment#2 "present-day control experiment" "for most models this experiment is not needed, but for some it is the control for experiments 8-9. There will be no natural forcing and anthropogenic influences will be set at present-day level. The control experiment should be long enough to extend to the furthest point in time reached by the end of the perturbation experiments (which branch from it). Thus the control should allow us to subtract any residual, unforced drift from the perturbation simulations." substract any residual, unforced drift ? -
Albatross at 15:44 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
Take note readers, Villabolo is changing his/her post in the face of criticism. Note too that that is something "skeptics" rarely, if ever, do. So for someone her to make the comment that Villabolo has "descended into rampant pro-AGW defensive posture" is simply false. I would also contend that it is an ad hominem and therefore violates the house rules. -
Albatross at 15:39 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
Luke @65, May I point out the irony of you lecturing Villabolo on being more thorough when you did not provide a single source from the reputable literature to support your assertions. Not one. A recent pamphlet prepared by the Royal Canadian Geographic Society (based on findings in the scientific literature) has this to say about conditions on the prairies, Canada's bread basket: "In fact given the IPO change - expect a cracker decade for Australian rainfall ahead - more Las Ninas and stronger ones. Boom time for producers?" And what do you base the above statement on? And what about this one: "If as some suggest the Pacific becomes a more El Nino like mean state and the world warms - the thermocline the Canadian/US wheat belt moves north, temperature nearer C3 optima for wheat, higher rainfall and more CO2" And a note of caution, Oz is not the centre of the universe when it comes to providing grains. I do agree with you that this is complex, and that the impacts may not all be bad, at least up to a point. Fortunately, those darn scientists (bless them) have been working on this for a long time, and the over whelming evidence is that a little warming (typically <2 C may benefit crops), but that beyond that things really start to tank. Listen to this (also click on "wheat" and "maize". Note that they are talking about local change sin temperature, not global, and that mean summer temperatures are projected to increase by 3 to 4 C. And if you doubt that droughts have a negligible impact on crops, then think carefully what happened in Russia last year, in 2007 in Europe in 2003, on the Canadian prairies in 2002. And there are many more examples. I have said this before, all the CO2 in the world is not going to help is the soil moisture drops below the permanent wilting point and under heat stress. Also, as others have pointed out, plants may be able to move, but people cannot necessarily, and then one is assuming that there is viable land to move to-- that last point should be obvious to someone living in a place like Australia, well at least it is to adelady. Oh, and what Marcus just said @70. -
RW1 at 15:10 PM on 18 April 2011Clouds provide negative feedback
Sphaerica (RE: 25), "They are not "greatly amplifying" small temperature changes. They do have some impact, but there's no reason to exaggerate things with "great" and "small" to try to score points." OK, fair enough. The point is the AGW theory claims the net effect of clouds is to amplify warming rather than attenuate warming. The mechanisms available for altering climate are: * Solar insolation (barely changes) * Orbital forcings (changes predictably on huge time scales) * CO2 (changes on any of 3 time scales, geologic=very slow, natural feedback=medium, anthropogenic=very fast * H2O (changes relatively quickly in direct proportion to temperature, and so it is the primary amplifier in power, but not a controller since it exerts no independent control of its own) * Albedo (can change relatively quickly, or slowly, but almost always as a response to other factors) * Clouds (change almost instantaneously, and positive/negative effects are arguable, but relatively inconsequential compared to the bigger factors)." If the Sun is the source energy and ultimately heat in the system, and if H2O changes so quickly in response to temperature - specifically warming, and water is the primary amplifier but not a controller, what is the controller? If the Sun is the only real heat source, and water concentration (the primary amplifier) is driven by heat from the Sun, the primary controller would need to modulate the amount of the Sun's energy allowed to enter the system. Clouds definitely do this since they make up about 3/4ths of the albedo and are constantly changing spatially and in time - all the time. Is it also a coincidence that clouds are made up of H2O and water vapor concentrations drive cloud formation? It is also another coincidence that water vapor is removed from the atmosphere from precipitation that emanates from clouds? If the net cloud feedback was positive in conjunction with positive water vapor feedback, what would prevent the temperature from rising significantly higher and higher from even just a few days or few weeks of abnormally warm weather? Yet this never happens - abnormally warm weather periods end and normal or colder weather inevitably commences. This is probably because the forces that drive evaporation/water vapor are not as strong as the combined forces of clouds and precipitation. This is fundamentally why net positive cloud feedback is so illogical. "* Land mass dispositions (which greatly affect albedo and the results of orbital forcings, but which only themselves vary on massively long timescales) Which is primary? At the onset and termination of glacial periods, the orbital forcings, but only through an albedo feedback, and in conjunction with a strong CO2 feedback, which in turn operates in conjunction with the strong H2O feedback. Outside of those periods of orbital forcings, under natural conditions, CO2 is the main long term driver, amplified by albedo, cloud and H2O feedbacks. During anthropogenic pollution, CO2 is the only control mechanism that operates on the time scales that we are witnessing, again amplified by all of the usual feedbacks." But clouds operate on even shorter time scales than CO2, and temperature fluctuations occur on much shorter time scales too. Let's not forget that the surface of the Earth is over 2/3rds water. The cycle of water -> water vapor -> clouds -> precipitation -> water is enormous. -
Marcus at 15:08 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
The point remains, Luke, that claims of "CO2 being plant-food" are incredibly simplistic & inaccurate, yet the Contrarians want to take a chance with our agricultural future based *entirely* on this simplistic attitude-with what amounts to a grand experiment on the only atmosphere we have. -
Marcus at 15:04 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
"You've descended into rampant pro-AGW defensive posture" Sorry Luke, but that's exactly the kind of language I've come to expect from someone who has descended into a "rampant pro-denialist defensive posture". If you want to be taken seriously, try removing some of the invective first. -
Chris G at 14:52 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
I think (not that my opinion should count for much) the original and the edited version are both fine. You can't get too nuanced in a basic version of this material without loosing the audience. FWIW, I found the article referenced by my first link. Hansen et al, 2006 Relevant information is in and around Figure 6. -
villabolo at 14:43 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
@51 Chris G: Not a problem, Chris. I'm just a non scientifically trained enthusiast. I change point #4 in my post to the following below. Tell me what you think. 4. The worse problem by far is that increasing CO2 will increase temperatures throughout the Earth; making deserts and other types of dry land grow. While deserts increase in size, other eco-zones, whether tropical, forest or grassland will try to migrate towards the poles. However, soil conditions will not necessarily favor their growth even if the temperatures are optimum. There will be some other minor changes throughout the post. -
Chris G at 14:29 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
villabolo #57, I'm not trying to take anything away from what you said, and I am sure that you in particular understand shifting climate zones. I'm trying to add to what you said for anyone interested in further reading, and also somewhat responding to the mistaken meme that our agricultural systems can adapt and continue to feed us all without substantial cost. Adelady, Yes, that was kind of my point. There is no land on which to develop agriculture south of, say, Victoria. If the climate zones shift 400-500 km southward, agriculture is over in that region. -
LukeW at 14:21 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
villabolo You've descended into rampant pro-AGW defensive posture Woodland thickening across savanna biomes - apart from frozen area is about 14% of the world's area - thickening or shrub encroachment is happening across Australia, the southern USA and southern Africa. Less fire is why (with CO2 also assisting C3 trees and shrubs over C4s grasses. That's less fire and more tree/shrub thickening and so less grass means less fire. In terms of the latest floods - what rampant silliness compared to facts - in fact the land surface condition away from water courses in very good. No massive erosion at all. As for low and zero tillage at odds with mechanised agriculture - ye gods man ! - do you ever get out and see what is happening around Australia. Major transformations in last 20 years. Minimum tillage is a first world revolution ! In fact machinery especially designed to cope with minimum tillage. Tell Monsanto there is no market for minimum tillage (they'll ROFL).Away from broad scale cropping sugar cane industry almost now universally trash blankets after a green harvest - not burns - soil surface always well covered. Yes Australian floods may have taken out some production temporarily - but what like they've done for 100s of years with La Nina by cool IPO combination ! Come on AGW influence ?? .... in fact Australia is set for a record cotton harvest. Cotton Australia estimates the crop will top four million bales this year, smashing the previous record. But floods also fill dams and replenish aquifers - and thank heavens ! "Winners and losers" means this - ENSO means rainfall is already not uniformly distributed. If as some suggest the Pacific becomes a more El Nino like mean state and the world warms - the thermocline the Canadian/US wheat belt moves north, temperature nearer C3 optima for wheat, higher rainfall and more CO2 - perhaps the CIA already know something we don't ! :-) (in this scenario eastern Australia gets the drought end of the oscillation). In fact given the IPO change - expect a cracker decade for Australian rainfall ahead - more Las Ninas and stronger ones. Boom time for producers? And of course with increased CO2 we haven't let the conventional breeders and genetic engineers loose yet? I would assume plenty of potential based on track record. My point is this issue is very complex and a universal assumption of worse on food security is not a well thought through response. If you are going to the do the CO2 fertilisation review - need to be much more thorough. -
adelady at 14:12 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
"...look at where major agricultural areas are now, there are a fair number which will not be readily migrated poleward." That polewards movement notion is very much a northern hemisphere idea. Look at a map and draw a line around the globe. Start at Capetown, then across to Perth, Adelaide, Hobart, Dunedin and finish up at Montevideo or Buenos Aires. Apart from that sharply narrowing tongue of southernmost South America, there _is_ no poleward land to replace any of those productive areas of South Africa, Australia, New Zealand and Argentina. -
Tom Curtis at 14:11 PM on 18 April 2011A Flanner in the Works for Snow and Ice
Ken Lambert @81, if your read the OP about Flanner, you will sea that, "A new paper by Flanner et al in Nature Geosciences tries to estimate the so called ‘cryosphere albedo feedback’ since 1979." (My emphasis.) It's right there in the first sentence. Therefore if we want to do a plausibility check on Flanner (which is technically what this exercise is), we need to compare the change in summer incoming energy flux from 1979 to 2008. That is, by a very conservative approximation, 1.35*10^21 Joules. If we extent the comparison period to 2010, the change is 1.51*10^21 Joules, again very conservatively estimated. What is more, even the original post by Sphaerica from which this debate sprung is clearly considering the change in arctic forcing between the 1978-2000 average and the present, ie, effectively 2010. So why you should suddenly be interested in the mean annual change in the change in the ice albedo forcing during the Arctic summer rather than, as we have been discussing, the mean annual change in the ice albedo forcing during the arctic summer is almost entirely mystifying. It does not even make much sense as mere passing curiousity. After all, as revealed by Piomas, the total ice volume has not been recovering each winter. The Ice does not need to melt back from the March of 1979 position each year. Therefore the change of the change is not a predictor of how extensive the ice melt will be each summer. This is a genuine feedback situation, with each summers melt making each successive summer's melt easier, and likely to be more extensive. (Note, likely, not guaranteed - there are other factors here.) -
TOP at 13:49 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
1. Plants will need extra water. Where will it come from? Rainwater is not sufficient for current agriculture and aquifers are running dry throughout the Earth. Actually some plants, or should I say trees do better with more CO2. It has been proposed to reforest the Sahara which is possible because of increased CO2. The key attribute certain trees have is that CO2 causes the pores that transpire water to close, reducing water requirements. A side effect of this reforestation is to consume the so called AGG solving another problem. -
Bob Lacatena at 13:39 PM on 18 April 2011Clouds provide negative feedback
24, RW1,If clouds... are instead acting to greatly amplify relatively small temperature changes...
They are not "greatly amplifying" small temperature changes. They do have some impact, but there's no reason to exaggerate things with "great" and "small" to try to score points....what is the primary mechanism controlling the energy balance of the planet?
I'm not sure why there must be a primary mechanism, and because there are multiple mechanisms, they all interact, they are all difficult to "force," and it becomes a question of semantics in arguing over which is "primary." The mechanisms available for altering climate are:- Solar insolation (barely changes)
- Orbital forcings (changes predictably on huge time scales)
- CO2 (changes on any of 3 time scales, geologic=very slow, natural feedback=medium, anthropogenic=very fast
- H2O (changes relatively quickly in direct proportion to temperature, and so it is the primary amplifier in power, but not a controller since it exerts no independent control of its own)
- Albedo (can change relatively quickly, or slowly, but almost always as a response to other factors)
- Clouds (change almost instantaneously, and positive/negative effects are arguable, but relatively inconsequential compared to the bigger factors).
- Land mass dispositions (which greatly affect albedo and the results of orbital forcings, but which only themselves vary on massively long timescales)
-
Ken Lambert at 13:16 PM on 18 April 2011A Flanner in the Works for Snow and Ice
Tom Curtis #78 - #1 "I have then multiplied by the total area.' Yes, but that is the total area lost relative to 1979. You need to look at the total area in 2010, relative to the total area in 2009 to ascertain the ice lost and the *annual* heat gain. And 2009 relative to 2008, 2008 to 2007 and so on... -
Marcus at 13:11 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
Another thing which isn't considered by so-called "skeptics" is what impact increased CO2, combined with associated changes in temperature & moisture, will have at the root-soil interphase-especially as regards the incidence of root-borne diseases. Its not an area that's been researched at length, but what little info I've seen suggests that disease incidence will become worse under AGW conditions. -
Marcus at 12:43 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
@ Ian Forrester. Yes, I'd read that very recently myself. Kind of puts the whole "CO2 is plant-food" argument into perspective! -
Ian Forrester at 12:29 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
If we want to see the effects of higher CO2 concentrations and hence higher temperatures on plant growth we should look and see what is happening at the molecular level. All of plant metabolism is controlled by various enzymes, literally thousands in any one organism. The key step in plant growth is the fixation of CO2 via the enzyme Rubisco (Ribulose-1,5-bisphosphate carboxylase oxygenase). Here are some recent findings on the biochemistry of Rubisco. The older studies showed that the enzymatic activity of isolated Rubisco (the enzyme responsible for the fixing of CO2 into organic metabolites) was increased at higher temperatures and higher CO2 concentrations. This allowed deniers to argue that this would be good for agriculture since it would allow for higher yields (forget about water and available nitrogen for now). However, there were always problems in getting reproducible levels of Rubisco activity (preparations had to be aged and/or treated to give maximum activity). Later research has shown that there is another layer of regulation affecting Rubisco activity (as is common with many enzyme system). A new enzyme, Rubisco activase, was found to be responsible for converting “inactive” to “active” Rubisco. And, surprise surprise, this new enzyme was found to be inhibited by higher temperatures and also inhibited by higher CO2 concentrations. This finding is probably responsible for the contradictory results found in experiments where varying temperatures and CO2 concentrations on plant growth have been conducted. http://www.ars.usda.gov/is/AR/archive/nov02/plant1102.htm http://www.pnas.org/cgi/content/abstract/97/24/13430Moderator Response: [DB] Hyperlinked URLs.
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