Arguments
Recent Comments
Prev 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 Next
Comments 88051 to 88100:
-
Albatross at 02:17 AM on 19 April 2011More Carbon Dioxide is not necessarily good for plants.
BP @103, "Let's see some real science." What a truly bizarre statement to make, especially after what you have done earlier on this thread. And since when is "your" science "real" science? I'll give the paper a read......good gracious I did not even have to get past the abstract. BP, please tell us why you chose to leave out this lesson from your list (which was so important that they included it in the abstract)? "Finally, the stimulation of yield by elevated CO2 in crop species is much smaller than expected." Oh and this, from the same paper: "Most important though will be understanding why our major food crops fail to achieve the improved production under elevated [CO2] that can be achieved in protected environments and by some non-crop species." There is some hope though: "Overcoming this could deliver a 10–15% increase in crop yields by 2050, an increase that could be critical with an anticipated 3 billion increase in global population coupled with climatic change adverse to crop production. " Yet from their final paragraph: "Overwhelmingly, this has shown that data from laboratory and chamber experiments systematically overestimate the yields of the major food crops, yet may underestimate the biomass production of trees." The authors clearly fail to see the hearty optimism of the 'skeptics'. -
villabolo at 02:13 AM on 19 April 2011More Carbon Dioxide is not necessarily good for plants.
@111 CBDunkerson: David Horton wrote: "Anyone else get the feeling we are just wasting our time answering this kind of stuff?" I try to keep mental note of the people who have proven themselves completely beyond reason and ignore them. Granted, that leaves whatever nonsense they post 'un-rebutted', but any such can always be addressed later should anyone suggest that it could have validity. In echoing that sentiment let me emphasize that we have to address ourselves to the general public with the idea in mind that a "Skeptic' will be looking over their shoulders and spouting off his nonsense. That means that we don't really need to emphasize technical arguments/rebuttals but instead simplify the issues in order to "innoculate" the public. -
villabolo at 02:04 AM on 19 April 2011More Carbon Dioxide is not necessarily good for plants.
@107 David Horton: "I am tired of that game." We need to play another game. -
Rob Honeycutt at 02:02 AM on 19 April 2011More Carbon Dioxide is not necessarily good for plants.
DM @ 119... Totally agreed. You might say that BP "Moncked it up." -
Albatross at 01:58 AM on 19 April 2011More Carbon Dioxide is not necessarily good for plants.
I would like to highlight a couple of things for readers, Arkadiusz made a post @83, trying to convince us that higher temperature will not be bad for the tropical forests. Two readers who took the trouble to dig a little deeper into the paper find that the results are not relevant to the current and future situation-- 200 years versus 10 000-20 000 time span. Now what does the skeptic do? Does he acknowledge this and cede the point? No, he ignores the critique and simply posts another paper @92. And nice try BP @97, but please do not insult our intelligence. You have been told repeatedly that this is not so much about where we have been or are but where we are headed if we continue under BAU. Your fraudulent graph was misleading and ignored the fact that its assessment agrees with the topic of the post-- moderate CO2 increases (and warming) favour an increase in biomass, but if CO2 goes way up, then vegetation does not fare well. Too much of a a good thing may very well be a bad thing. Try consuming a cup or two of salt to find out. Luke @100, Yes, you were speculating, thanks for confirming. I do not need links on how ENSO and IPO affect rainfall thanks, that is not what is at issue here so much as you claiming that we are headed for a period of more frequent La Ninas. That may or may not be true, but unless backed up by some science, it remans simple speculation. With that said, you seem to be basing your projection on the work of Verdon and Franks (2006). At least one of the papers that you cited has not helped you case: "Although there appears to be no overall trend toward wetter or drier conditions [over Queensland], the reconstructions suggest that the variability of rainfall and river flow has increased during the twentieth century with more very wet and very dry extremes than in earlier centuries, as projected for the region as a consequence of global warming." An increase of rainfall variability is not conducive for better crop growing conditions. And their work validates the IPCC projections. And I should have not have to point this out, but flooding (as was associated with this past La Nina) is clearly not conducive for agriculture either. Too much water is also a bad thing for crops and and other vegetation. -
Dikran Marsupial at 01:53 AM on 19 April 2011More Carbon Dioxide is not necessarily good for plants.
Rob Honeycutt@116 For me the issue is that BP was using a graphic from a source that contradicts his position without mentioning that fact. It is a bit like taking a quote from a paper out of context to support an argument, where the paper as a whole supported an opposing position. Using a graphic or a quote from a report implicitly suggests that the report provides some support for your position. Somehow I don't think it would have passed without comment if say James Hansen had used a cropped picture from a climate skeptic report that was cropped in such a way as to ignore the central message of the report. -
Gilles at 01:46 AM on 19 April 2011Christy Crock #3: Internal Variability
and an example of publication (but I'm sure there are others and you know it very well) http://www.esrl.noaa.gov/psd/people/gilbert.p.compo/CompoSardeshmukh2007a.pdf " Several recent studies suggest that the observed SST variability may be misrepresented in the coupled models used in preparing the IPCC's Fourth Assessment Report, with substantial errors on interannual and decadal scales (e.g., Shukla et al. 2006, DelSole, 2006; Newman 2007; Newman et al. 2008). There is a hint of an underestimation of simulated decadal SST variability even in the published IPCC Report (Hegerl et al. 2007, FAQ9.2 Figure 1). Given these and other misrepresentations of natural oceanic variability on decadal scales (e.g., Zhang and McPhaden 2006), a role for natural causes of at least some of the recent oceanic warming should not be ruled out. Regardless of whether or not the rapid recent oceanic warming has occurred largely from anthropogenic or natural influences, our study highlights its importance in accounting for the recent observed continental warming. Perhaps the most important conclusion to be drawn from our analysis is that the recent acceleration of global warming may not be occurring in quite the manner one might have imagined. The indirect and substantial role of the oceans in causing the recent continental warming emphasizes the need to generate reliable projections of ocean temperature changes over the next century, in order to generate more reliable projections of not just the global mean temperature and precipitation changes (Barsugli et al. 2006), but also regional climate changes." No need to say that if even the decadal variability may be "misrepresented", this can only be worse at the century timescale. -
Rob Honeycutt at 01:42 AM on 19 April 2011More Carbon Dioxide is not necessarily good for plants.
David Horton @ 107... Yes, it's worth going through this over and over and over (IMHO). I always say this: It's not about changing anyone's mind who is posting here. We will never change Gilles, BP, or any other of the minds that are already made up. But in responding to their claims and debating their positions we have the opportunity to change the minds of others who come to SkS to read about this issue. Think of it as a public debate with a large audience. When you post here you are up on the stage making a point. You don't need to convince the person at the other podium whom you're responding to. You need to convince the audience. I would contend that the audience is always changing too. Even though we might have the same discussions here repeatedly with the cast of characters, there are more and more people reading SkS all the time. New minds ready to learn more about climate science. One of the great things about this site is the heavy moderation. When I go read WUWT it's more like you walked into a clubhouse where everyone thinks alike and is slapping each other on the back, and attacking anyone who doesn't think like they do. Here at SkS there is a more hearty, genuine debate. -
villabolo at 01:39 AM on 19 April 2011More Carbon Dioxide is not necessarily good for plants.
@104 CBDunkerson: "As to the impact on plants specifically... it is well known (unless one is an evolution denialist also) that all lifeforms evolve to best survive within the environment around them. The longer a particular element of that environment is relatively stable the more time lifeforms will have to evolve to adapt to it. Atmospheric CO2 levels had been constrained to a range between about 180 and 280 ppm for millions of years. Every plant on the planet has therefor been evolving towards the ability to best survive within that CO2 range for millions of years. There is no way that they will all now be able to adapt to radically different CO2 levels within a matter of decades. Some will retain characteristics from higher CO2 periods in the past which will allow them to cope, but others will not." Excellent point. I was worried that a quick and easy "Skeptic" response would be to say something like; "In the good old Dinosaur days, plants did just fine with elevated CO2". The quick and easy rebuttal would be to say that plants had tens of thousands of years with which to evolve adaptations. Then one could bring up the Paleocene-Eocene Thermal maximum took 20,000 years to develop and yet major catastrophes ensued. As for the oxygen analogy, it would be better to revise it for basic level readers. Something like; "If the percentage of oxygen were to double, it would allow for massive fires. Even wet forests would burn." -
Rob Honeycutt at 01:23 AM on 19 April 2011More Carbon Dioxide is not necessarily good for plants.
BP said..."It means the curve up to the point where I've clipped it can be checked using actual data, beyond that it is pure fantasy." You can claim that if you like but you need justification for making such a claim. By any standard you very definitely don't clip the way you did without noting that you've done so and explaining why you did it. I'm surprised that you're defending what you did instead of apologizing. Quite honestly, I'm going to have a very hard time taking anything you say seriously from here out. -
villabolo at 01:04 AM on 19 April 2011More Carbon Dioxide is not necessarily good for plants.
@100 LukeW: ""And you want those La Ninas to get stronger?" YES PLEASE !! Would make us billions ! (with some collateral damage too but life wasn't meant to be easy) You would like another 20 year drought cycle instead ...?" I can see you're not Australian (Please tell me that your not). "Collateral damage"? Is this the military? Do you seriously think what they went through is worth a bumper crop of wheat; assuming it doesn't get ruined? Perhaps a cold blooded cost analysis is in order? How much lost in damage to homes and infrastructure versus how much gained by, what, a 10 or 20% increase in yield? Having mentioned billions of dollars to be made, please tell me how many billions will be lost? I believe I said it before; any hypothetical benefits to agricultural growth will be more than diminished by property and infrastructure damage; not to mention lives lost. Who gets to be the "winners and losers" in this scenario? Those who eat versus those who drown? If one were to play God then the wish would be for moderate La Ninas. But that's not what's going to happen. As for contrasting that with 20 year drought cycles, I really see that as a difference without a distinction. It's like having this choice:
-
Gilles at 01:02 AM on 19 April 2011Christy Crock #3: Internal Variability
"One could ask what relevance 'long timescale variability' has to the current forced climate change?" It "just" changes the influence of forcings accordingly . "The obvious answer to this point, is that as the references you yourself provided clealy state, modern GCMs don't exhibit these drifts and no longer need flux adjustments to correct them." I already answered that precisely here . No need to say it again - you just prove with your models what you have carefully worked out to get. -
Dikran Marsupial at 00:44 AM on 19 April 2011Christy Crock #3: Internal Variability
Gilles@108 "If this were a generic feature of GCM models, then there wouldn't be any drift : everything should be "burnt-in" in a few weeks." The obvious answer to this point, is that as the references you yourself provided clealy state, modern GCMs don't exhibit these drifts and no longer need flux adjustments to correct them*. *Although the drifts are not solely due to initialisation anyway, so the argument was invalid to beign with Sorry Gilles, I am bored with your trolling, it is obvious you have no substantive point to make, are not even reading your own sources, just quote mining, and are merley trying to disrupt sensible discussion. Sadly you have achieved your goal. -
Tom Curtis at 00:38 AM on 19 April 2011A Flanner in the Works for Snow and Ice
Ken Lambert @83, if you multiply the TSI measured in Watts/meter squared by a number of factors representing atmospheric absorption, cloud and surface albedo, atmospheric absorption, and the extended surface covered by the incoming light due to the low angle of incidence; then further multiply by time factors of 60 and 60 and 24 and 90, it is not mathematically possible that what you have calculated is the cumulative energy flux over thirty years. And lest there be any doubt over what time period the incoming energy has been calculated, here is the relevant formula from my spread sheet, which calculates the energy input per meter squared from effective change in radiance absorbed by the surface as a result of sea ice melt: =I105*60*60*24*90 Put in the simplest terms, 60*60*24*90 =/= 60*60*24*365.25*32; 11688 does not equal 90. Nor is it a possible mathematical confusion that they are the same. I perfectly understand that you are getting desperate, defending as you are, the in defensible. But resorting to such ridiculous tactics as pretending to the confusion you apparently espouse only succeeds in making you look the complete fool. At this stage I cannot be any clearer about my method. As this is already a repeat of this information, there can be no basis for your confusion other than a pointless rhetorical strategy. Should you persist in this ( -snip- ) strategy, I will request that the moderators take notice of your obvious trolling.Moderator Response:[Dikran Marsupial] Bold tags (hopefully) fixed.
[DB] Inflammatory term snipped.
-
muoncounter at 00:30 AM on 19 April 2011Christy Crock #3: Internal Variability
Gilles #106: "I don't have to "provide" evidence of long timescale variability " Of course not. You can just throw out the teaser of 'long timescale variability could be ... ' and not bother with evidence, proof or theory. That's the advantage of saying 'no' to everything you don't like. One could ask what relevance 'long timescale variability' has to the current forced climate change? -
bushybest at 00:30 AM on 19 April 2011More Carbon Dioxide is not necessarily good for plants.
I give up on this post. There is so much non-science splattered around the comments and that includes the original posting.The whole thing is a scattergun target. How about a reality based and referenced article/post on actual science for a change? [personal attack snipped]Moderator Response: [Dikran Marsupial] Please read the comments policy and keep constructive criticism impersonal. -
Gilles at 00:29 AM on 19 April 2011Christy Crock #3: Internal Variability
"This is of the order of a few weeks." If this were a generic feature of GCM models, then there wouldn't be any drift : everything should be "burnt-in" in a few weeks. What you don't understand is that when running a numerical model, you can only measure the characteristic variability timescales of the model itself, not of the reality it is supposed to describe. The limit cycle that can arise in a non linear ,chaotic model are generically *not* well predicted, again- and this is extremely difficult, and so to say impossible, to make a reliable diagnosis from this kind of computation. You're using an argument for "evidence" with a tool that is simply not appropriate for this use. Of course, there are plenty of signs of variabilities at hundreds or thousand years levels -and this is totally compatible with the order of magnitude of thermohaline circulation and heat transport timescales by the oceans. -
Alexandre at 00:22 AM on 19 April 2011More Carbon Dioxide is not necessarily good for plants.
les at 22:58 PM on 18 April, 2011 That's a great system :-) Specially in these days of Science As A Contact Sport. -
Dikran Marsupial at 00:17 AM on 19 April 2011Christy Crock #3: Internal Variability
Gilles@106 I explained earlier that the initial conditions don't affect the model ensembles provided you let them "burn-in". This "burn in" phase is presumably what you mean by "relaxation time scale". This is of the order of a few weeks. That is why numerical weather prediction is only accurate to a prediction horizon of a few days; that the models rapidly forget their initial conditions. Now if you have evidence that is not the case, lets hear it. The initialisation prescription given is basically just saying the models need to be properly burned in, while considering the need for the comparison. Nothing more. I am not cliaming there is no long timescale unforced variability, just that there is little evidence to suggest that such a thing exists and therefore it is not rational grounds for significant doubt on the model projections. If you want to assert that long timescale unforced variability is a reason to doubt the model projections then the burden is on you to give credible evidence that it even exists. -
Ken Lambert at 00:03 AM on 19 April 2011A Flanner in the Works for Snow and Ice
Nice try Tom, You are forgetting that if we look at Dr Trenberth's 0.9E20 Joules/year (rounded up to 1E20 Joules in his Table) based on the 2004-08 period, and assume the same rate of heat energy accumulation for 31 years (1979 - 2010) then you will get 28E20 Joules as the total energy absorbed. And that is for sea ice melt alone. In the same 31 year period you are calculating 15.1E20 Joules - roughly half the Trenberth cumulative figure. In that period (31 years) assuming that Trenberth's global imbalance was something between 0.5 and 0.9W/sq.m (say 0.7W/sq.m average) or 112E20 Joules/year for 31 years, then the Earth would have accumulated 31 x 112 = 3472E20 Joules of extra heat energy. Your number of 15.1/3472 = 0.004 which is 0.4% of the Earth's uptake, and Trenberth's number 28/3472 = 0.008 or 0.8% of the total Earth's uptake in 31 years. This makes my original point quite well. The 4.4% of the globe surface above the Arctic circle actually accounts for 0.4% to 0.8% of the global heat energy imbalance absorbed based on your and Trenberth's figures. -
Arkadiusz Semczyszak at 23:57 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
CBDunkerson Atmospheric CO2 levels had been constrained to a range between about 180 and 280 ppm for millions of years. Every plant on the planet has therefore been evolving towards the ability to best survive within that CO2 range for millions of years. < a href =http://meetingorganizer.copernicus.org/EGU2011/EGU2011-10649.pdf>Long-term effect of elevated CO2 concentration on temperature optimum of photosynthetic CO2 assimilation in two tree species, Holisova et al., 2011.: “The eight-year-old trees were grown in glass domes at the experimental research site Bílý Kˇríž in the Beskydy Mts. and they were exposed for three growing season to ambient (AC; 380 _mol(CO2) mol-1) and elevated CO2 concentrations (EC; 700 _mol(CO2) mol-1).” “Our data thus support the initial hypothesis that long-term growth of plants under elevated CO2 concentration leads to the acclimation of photosynthesis and other related processes to higher temperature.” Cited above species of trees live unchanged for millions of years - probably the "something" they need „the acclimation of photosynthesis” do „700 _mol(CO2) mol-1” ... Optimum photosynthesis for most species of C3 plants is 400-600 ppmv CO2. It is higher at higher temperatures . C4 formed as a response to unusually low levels of CO2 (<350 ppmv CO2). At 180 ppmv CO2 - some C3 species stop growing - less than 150 ppmv CO2 - the most die back (knowledge of "textbook"). -
Tom Curtis at 23:48 PM on 18 April 2011Muller Misinformation #2: 'leaked' tree-ring data
climatewolf #10, I'm sorry to hear about your real life crisis, and hope it has been resolved in a satisfactory way. I'm sure I speak for DB and John Cook as well when I say that we'ld be be delighted for you to continue reading, and commenting. It is after all, what the site is for. Certainly John Cook has never objected to my putting my layman's oar in. -
Gilles at 23:47 PM on 18 April 2011Christy Crock #3: Internal Variability
"I have already explained to you that initial conditions do not affect the conclusion of model ensembles and why." which is wrong, or rather, depend on the relaxation time scale of the model. "So what evidence do you have that model projections are sensitive to the initial conditions? Again, search for "initialize" in http://www-pcmdi.llnl.gov/ipcc/standard_output.html, and you will find plenty of occurences such as : "should initialize from a point early enough in the pre-industrial control run to ensure that the end of all the perturbed runs branching from the end of this 20C3M run end before the end of the control. This will enable us to subtract any residual drift in the control from all runs that will be compared to it." if initialization is immaterial, why give a prescription ? "What evidence do you have that long timescale unforced variability is a significant part of the climate system?" I don't have to "provide" evidence of long timescale variability - the burden of the proof is for the one who claims there isn't. Do you claim that, or not ? you can provide either strong theoretical , or strong observational evidence. I would accept both. I just don't see where they are. -
Ken Lambert at 23:38 PM on 18 April 2011The e-mail 'scandal' travesty in misquoting Trenberth on
Alec Cowan #135 Calm down Alec, the spray is amusing but fools no-one with the hyperbole and 'For God's sake don't you know that??' crude attempts at argument by intimidation. Just point out exactly the errors made in the K&D paper and where the numbers are wrong. -
climatewolf at 23:32 PM on 18 April 2011Muller Misinformation #2: 'leaked' tree-ring data
Hi Tom Curtis, Apologies I was offline with a real life crisis the last few days. Thank you for your response, I see clearly the points you are making and thank you and DB for alieviating my concerns and explaining you POV. I hope you (all) and Mr Cook will not object to my continuing to read this site and dropping my very layman oar into the water on occasion to share my POV. I may not always agree with you on all points, but I will try to be as open minded as I can be and ask questions/challenge assumptions where I can in a positive manner. Regards WolfModerator Response: [DB] Best wishes for your situation and what the future holds for you. Your participation is welcome and valued in this forum. -
CBDunkerson at 23:32 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
David Horton wrote: "Anyone else get the feeling we are just wasting our time answering this kind of stuff?" I try to keep mental note of the people who have proven themselves completely beyond reason and ignore them. Granted, that leaves whatever nonsense they post 'un-rebutted', but any such can always be addressed later should anyone suggest that it could have validity. Besides, if the thread remains short then the moderators usually have sufficient time to put in links to existing posts which give reality based evidence. -
Dikran Marsupial at 23:30 PM on 18 April 2011Christy Crock #3: Internal Variability
Gilles@103 I don't recall anyone saying that computer models were the only line of evidence suggesting that long term unforced variations are unlikely. So the comment about changing stories is a strawman and you know it. This discussion stems from your question about initialisation of models on post 67. I have already explained to you that initial conditions do not affect the conclusion of model ensembles and why. If you want to show that they do, then you need to provide evidence. So far you have provided none whatsoever. You have not provided any evidence of long term unforced variability. Pointing out there is variability in the data does not mean that it is unforced. You can't have it both ways, if you dismiss the attribution of changes to forcings as being a "sociological feature of modern science", then it is equally a "sociological feature of modern science" for you to attribute it to unforced variability. So what evidence do you have that model projections are sensitive to the initial conditions? What evidence do you have that long timescale unforced variability is a significant part of the climate system? No word games, just give straight answers to those three questions. -
les at 22:58 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
107 David Horton "Time really is up for all this" Maybe we need a new form ofrefereeingmoderation?
-
HumanityRules at 22:55 PM on 18 April 2011Solar Hockey Stick
The issue, as I see it, isn't whether the solar activity variation is high or low over the MWP/LIA period but rather whether that observation fits well with how we understand the 'control knobs' of the climate. There's an interesting series of papers in PAGES Newsletter March 2011. I don't know what PAGES is, suspect this work isn't peer-reviewed but it does appear to be showing work from some important scientists who work on this problem. I was struck by the conclusions in the modelling paper (starting page 7). I'll just reproduce the conclusion in full and leave it to yourself to decide just how much confidence we should have in our present understanding of the science. I think it's worth reading the rest of these papers. "Conclusions The results presented here highlight major discrepancies between millennium simulations and reconstructions. If proxybased reconstructions were considered reliable and changes in radiative forcing factors were responsible for the MCA–LIA reconstructed temperature signal, these results would have implications on our understanding of the MCA–LIA transition. These discrepancies suggest that either the MCA–LIA changes arose from internal variability only, or transient simulations with state-of-the-art AOGCMs fail to correctly reproduce some mechanisms of response to external forcing: for instance, changes in the tropics like the enhancement of the zonal gradient in the tropical Pacific is not well simulated, with implications for related teleconnections elsewhere. Most models have used relatively high TSI variations from the MCA to the LIA and their pattern of response is typically a uniform warming in the earlier period. In spite of this, there are considerable differences among the simulations that highlight a feasible influence of initial conditions and internal variability. Furthermore, if reduced levels of past TSI are given more credit, as in the MPI-ESM-E1 ensemble, the temperature response for the MCA–LIA is less uniform in sign and visibly more influenced by internal variability. Therefore, under both high and low TSI change scenarios, it is possible that the MCA–LIA reconstructed anomalies would have been largely influenced by internal variability." -
Gilles at 22:52 PM on 18 April 2011Christy Crock #3: Internal Variability
0.015°C/yr of course. -
Gilles at 22:51 PM on 18 April 2011Christy Crock #3: Internal Variability
I make no supposition : I just say that the use of computer simulation is not a good criterion to exclude long term variations, since both computation methods *and* initial conditions have been carefully selected with this criterion. Now you use a totally different argument by saying :"The unforced stabilty of the climate seems well established by the paleoclimate record. " because this argument doesn't rely at all on computer simulations but on observations ! so you change the argument and say now " but paleoclimate observations exclude a natural 0.15°C/yr during 50 years". Which is again wrong : paleoclimate data don't exclude this kind of variations. " Can you give an example of a major shift in climate that cannot be attributed to a change in forcing?" "being attributed" being not an objective variable, but kind of a sociologic feature of current science, I can't answer this question. I stick on facts. But a 0.5 °C variation in 50 years wouldn't certainly be called a "major shift in climate" for paleoclimatic data (after all, who in the world is living in a different "climate" from his parents ?) - and yes of course there are plenty of such variations in the past - that cannot clearly be attributed to a change in forcing. -
les at 22:34 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
Got to be said, that FACE stuff is interesting. The plots look log (asymptotic) or, at best, log-linear; not exponential (that's the 'up shot') and compatible with point 6. of the blog post. As has been mentioned, one can expect some improvement when one or another resource becomes more abundant, allowing other resources which are already abundant to be utilized and that will self-limit... in system like that, you'd expect an asymptotic improvement in the absence of any negative influences (increase in premeditation etc.) Good data. -
Alexandre at 22:29 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
David Horton at 22:24 PM on 18 April, 2011 I'm with you. -
Bob Lacatena at 22:28 PM on 18 April 2011Clouds provide negative feedback
RW1,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?
Yes, it is coincidental. That is, both are true, but neither mean anything....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...
Yes it does, every time the seasons change. That is, the change in temperature in the temperate zones is greater than could be accounted for by the mere change in hours of insolation and angle of incidence of the sun (and change in albedo from winter snow to bare ground). Humidity also rises, and the GHG effect from this amplifies the temperature. This happens, any you experience it, every spring. But to give your question a more direct answer, you seem to be describing a runaway. As long as the feedback is less than the original forcing, it is positive, but not a runaway. This is the simple case of a convergent versus a divergent series in mathematics.This is probably because the forces...
No. This is an assumption without foundation (as evidenced by the word "probably"). Clouds form or dissipate in a matter of hours. What would be needed to change climate would be a major change in the pattern in which clouds form or dissipate -- where, or when, or how much, by a significant degree, over a long period of time. There is no firm logical reason to think that this would happen (Lindzen argues that it should, but I and most of climate science find his arguments very unconvincing, and observational evidence to date is indecisive, which by itself tells you that it's not a "major" control, or else it would be obvious and unarguable). The fact that you think it could happen easily is in no way evidence that it does happen.But clouds operate on even shorter time scales than CO2, and temperature fluctuations occur on much shorter time scales too.
So if they had a moderating effect they would be a serious damper in the system. But they don't. And if they were, because they operate so quickly, you would see their effect instantly. Which is exactly why clouds cannot be a major factor. On the time scales over which clouds vary, if in fact they were a moderating influence, then the temperature of the earth would never, ever vary by more than a fraction of a degree (or the clouds would quickly step in and stop it). You'd never have ice ages, Medieval Warm Periods, Little Ice Ages, or any notable variations. And yet over the history of the earth the temperature has varied by as much as 10˚C. Anything which operates on that fast a time scale is either the primary control, or it's not a control at all. All evidence points to "not at all." It may be a slightly positive or slightly negative feedback, but it's not a control, and not even a major feedback (compared to H2O, CO2, and albedo). Look here for further information on how we know that climate sensitivity is not low, so any moderating influence of clouds cannot be a major, fast acting factor. Oh, and as an aside, I did forget one control from my previous list:- Aerosols (due to volcanic activity, these can act very, very quickly, but by themselves are normally short lived, but gain "traction" by reducing the planet's albedo long enough to instigate other feedbacks which can be longer lived).
-
David Horton at 22:24 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
Anyone else get the feeling we are just wasting our time answering this kind of stuff? That the responses can keep getting produced, over and over, and back will come the same old nonsense, over and over. Time really is up for all this. Ten years ago we argued because we thought there was a chance of bringing facts to bear, changing minds, influencing people. The last ten years have shown that there are a core of people who will never stop resisting in order to prevent any political and economic action. And feeding off them are the politicians like Abbott, telling people they can be better off because he won't "tax" them to save the planet, fools like Howes demanding no change at all to the present economic structure, and the big corporations demanding the same. All just a game, as if we can decide not to respond to greenhouse gases and then everything will be alright. I am tired of that game. -
RSVP at 22:14 PM on 18 April 2011Waste heat vs greenhouse warming
For the most sea worthy ships, waves may wash on deck. No problem; when built properly, there are amply ways for the water to return to the sea. For this reason, the ship does not sink. Put a small hole in the hull however, and if there is no bailing, eventually the proud vessel will find its davy jones. Our spaceship Earth is no different. All surfaces that pick up heat from the Sun act conversely to radiate the same. While a slight change in CO2 may be changing the atmospheric temperature profile, the net entropy remains unchanged. And while energy cannot be destroyed, the same cannot be said for our lovely Planet. -
Alec Cowan at 22:14 PM on 18 April 2011The e-mail 'scandal' travesty in misquoting Trenberth on
@Ken #134 Call me coy or paint me purple, but firstly you have to substantiate your assertion about Knox & Douglas using other than 0-700m layer in figure 1 and all 4 methods. How come you can quote some conclusion without giving the scope of that conclusion. For God's sake Ken, it's a 2-page paper with almost all mathematics stripped from it!! I'm telling you again, Knox & Douglas use 0-700m layer and refer papers dealing with not always the same layer. You are telling otherwise and you refuse to substantiate it just by reading the paper and copypasting what applicable to identify some piece of information. C'mon! Do you think that by labeling something OHC or Argo that matter is settled? C'mon, Ken! Don't insist with that '*deep ocean*' (what are those **** symbols? some kind of magic spell?) unless you can give direct evidence from the paper or compare its figures with Argo's site or other papers. I think you are worried because Knox & Douglas' goes very roughly on the same way Trenberth did when he talked of the "travesty" and your argumentation backfired. -
CBDunkerson at 22:12 PM on 18 April 2011Muller Misinformation #3: Al Gore and polar bears
chriscanaris: See the IUCN Polar Bear Specialist Group site. As I mentioned before, these are the people who produced the data which the map above is based on. The site also has information about the conditions impacting the various sub-populations. Similar conditions (allowing for continued population growth) exist for the larger neighboring 'Gulf of Boothia' population, but there increased hunting by humans has caused numbers to stabilize. For instance, the lone 'growing' sub-set at M'Clintlock channel consists of a tiny population of approximately 284 bears, and is believed to be growing simply because the population is still recovering from hunting. Until recently that was true of most of the sub-populations... but declining habitat has now reversed the trend in many areas as seen above. M'Clintlock channel has continued to experience significant sea ice coverage and thus hasn't seen population declines yet. I believe the Foxe Basin population status is unknown just because it is a remote region (most of the bears are found on various islands un-inhabited by humans) which has been difficult to study. There are new aerial surveys being conducted to fill out the picture on this group. -
Alexandre at 22:08 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
JMurphy at 18:36 PM on 18 April, 2011 Re PETM BTW, I find the PETM a fine example to contrast natural variance of temps and CO2 with the present anthropic one. There we had a ~5ºC variation in 10 to 20 thousand years, and that was a specially wild and fast variation in Earth's climate, specially if we consider we were not coming out of an Ice Age. It affected so much Earth's ecology that it caused a lot of species to shift in occurrence, adapt or be extinct. Now we're doing it over one order of magnitude faster: 5~6 degrees in one or two centuries (maybe more, if you consider the 200 year span). Species are not free to roam through the continents, as most ecosystems are fragmented by human occupation, even if species could move this fast. And we see people trying to argue how will this be benign to the planet, or that the variance is natural. -
Marcus at 21:49 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
Until these FACE trials are able to mimic *all* the conditions expected to exist in an enriched CO2 world (including more extreme hydrological cycles & increased temperatures), then there is only so much relevant information that can be gleaned from them. What can be gleaned is that, even in ideal conditions, its unlikely that the rather modest long-term biomass increases seen so far will be sufficient to offset losses due to all the other detrimental impacts of global warming. Also, the results of FACE trials-even under ideal conditions-as regards disease & pest infestations, not to mention nutritional value, don't exactly paint a very pretty picture for our future. -
CBDunkerson at 21:48 PM on 18 April 2011CO2 lags temperature
novandilcosid wrote: "It is being claimed that CO2 makes temperatures hotter than they otherwise would be. There does not seem to be support for this in the data presented in the headline post." That CO2 causes higher surface temperatures (aka 'the greenhouse effect') was first proven by John Tyndall more than 150 years ago. Articles explaining how this works and correcting other fundamental errors in your analysis above can be found on this site at; Has the greenhouse effect been falsified? and The greenhouse effect and the 2nd law of thermodynamics -
CBDunkerson at 21:39 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
I love the medication analogy in the article. It is a simple example that most people will easily understand and from there see the obvious fallacy of the 'more CO2 is always good' argument. As to the impact on plants specifically... it is well known (unless one is an evolution denialist also) that all lifeforms evolve to best survive within the environment around them. The longer a particular element of that environment is relatively stable the more time lifeforms will have to evolve to adapt to it. Atmospheric CO2 levels had been constrained to a range between about 180 and 280 ppm for millions of years. Every plant on the planet has therefor been evolving towards the ability to best survive within that CO2 range for millions of years. There is no way that they will all now be able to adapt to radically different CO2 levels within a matter of decades. Some will retain characteristics from higher CO2 periods in the past which will allow them to cope, but others will not. Thus, even without considering global warming's impact on water resources, pests, and other things which will impact plants... the changing atmospheric CO2 level alone will alter (likely already is altering) the growth patterns of plants all over the world. Another analogy: Humans require oxygen to live. However, we have evolved to process oxygen at the levels currently found in the atmosphere. If the partial pressure of atmospheric oxygen increased to four times current, oxygen toxicity would kill every human being on the planet (unless they were in some sort of environmentally controlled space). Given enough time, plants (or humans) could evolve to adapt to radically different levels of essential 'life giving' gases in the Earth's atmosphere. However, we are causing these changes on a scale measured in decades while those kinds of evolutionary changes would require millennia. -
Berényi Péter at 21:23 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
Let's see some real science. Journal of Experimental Botany (2009) 60 (10): 2859-2876. doi: 10.1093/jxb/erp096 First published online: April 28, 2009 Elevated CO2 effects on plant carbon, nitrogen, and water relations: six important lessons from FACE Andrew D. B. Leakey, Elizabeth A. Ainsworth, Carl J. Bernacchi, Alistair Rogers, Stephen P. Long & Donald R. Ort Lessons:- carbon uptake is enhanced by elevated [CO2] despite acclimation of photosynthetic capacity
- photosynthetic nitrogen use efficiency increases at elevated [CO2]
- water use at both leaf and canopy scales declines at elevated [CO2]
- dark respiration is significantly stimulated in soybean leaves grown under elevated [CO2]
- stimulation of carbon uptake by elevated [CO2] in C4 plants is indirect and occurs only in situations of drought
- the [CO2] ‘fertilization’ effect in FACE studies on crop plants is less than expected
-
Marcus at 20:43 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
"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 ?)" Gilles, that's because its only an article *about* the study, not the full study itself. I doubt the study would have gotten published *unless* they included full results &-judging from what they say in the article-the results don't tell a great story for the yield effects of beetle infestations on soybean plants grown in enriched CO2 conditions. Also, consider the increased cost of pest management, given the increased life-cycle & breeding times of beetles under enriched CO2 conditions-costs which will definitely be passed onto consumers. Seriously, your ability to ignore data that doesn't fit your agenda is quite astounding. -
les at 20:43 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
97 - Berényi Péter "It means the curve up to the point where I've clipped it can be checked using actual data, beyond that it is pure fantasy." It would, of course, be important to see the source research behind the graph... but I doubt that the lines up to 'now' are composed of data sets which have been gathered between 1860 and now, from the whole world... How was the graph composed? You know, Science is about understanding the evidence presented, not making unverifiable claims about the meaning of the bit of a graph that happens to take your fancy. -
LukeW at 20:39 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
"And you want those La Ninas to get stronger?" YES PLEASE !! Would make us billions ! (with some collateral damage too but life wasn't meant to be easy) You would like another 20 year drought cycle instead ...? La Nina = recovery, replenished dams, refilled aquifers, breeding cycles, Murray Darling flowing, fish migration and spawning, new seed stores, bird breeding - it's great stuff. Villabolo - I believe in climate change - but we need precision in the arguments - and a robust few of historic climate variation. (1) ENSO - first (2) IPO - second (3) climate change a long way back at 3rd - but eventually could become the main game albeit an unpredictable one (with winners and losers) Albatross: La Ninas and IPO among others El Nino-like mean state Remember I was only speculating about winners and losers. But US agriculture becoming an AGW winner would be ironic wouldn't it?Moderator Response: [mc] fixed link text. Please provide context for links. Link-only comments are not usually helpful and may be deleted. -
Marcus at 20:33 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
Oh &, John D, I think you forgot to mention this part of the story: "Fungal biomass of Fusarium pseudograminerarum significantly increased in wheat grown under eCO2. In absence of high levels of varietal resistance, crown rot will result in a reduction in yield (and quality) in future climates, particularly in drier years". Sort of puts a dint in your theory that CO2 magically improves yields under *all* circumstances. -
novandilcosid at 20:29 PM on 18 April 2011CO2 lags temperature
1. The Greenhouse theory is not straightforward. Absorption figures for CO2 at STP show that ALL the surface energy emitted in the CO2 band is absorbed within the first 500m of atmosphere, and the majority below 50m (0.5% of the atmosphere). Doubling CO2 has a negligible direct effect: ALL the energy is still absorbed into the atmosphere, just at half the altitude. 2. At the top of the atmosphere, using the same figures, but adjusting line shapes and amplitudes for temperature and pressure, it is clear that the greater portion of the 15-18W/m^2 emitted to space by CO2 is being emitted by the ~10% of the atmosphere lying ABOVE the Tropopause. Rough figures are: from 11-12.5km, 5%; 12.5-15km, 10%; 15-17.5km, 12%, 17.5-20km, 13%;20-25km, 20%; above 25km, 40%. If you increase CO2 concentrations, emissions are from higher levels, and an even higher proportion will be above the tropopause. IE more CO2 has a strong cooling effect. 3. Notwithstanding the above, the claimed feedback effect of CO2 on the ice-core temperatures is very shaky. I looked at the figure and note the long lag in the FALL in CO2 concentration. Why does the CO2 not hold up the temperature fall? Where is the mathematical model and its comparison with the data? At present the data does not seem to support the hypothesis. 4. The data unequivocally shows a lag between temperature and CO2 concentration. It is being claimed that CO2 makes temperatures hotter than they otherwise would be. There does not seem to be support for this in the data presented in the headline post. -
Marcus at 20:27 PM on 18 April 2011More Carbon Dioxide is not necessarily good for plants.
John D, we've been over this before. (1) The results you quote are, from memory, *only* for the most ideal conditions-something you fail to point out. (2) If the results were as positive as you claim, then why are the lead researchers so circumspect about the results? Indeed, the researchers make a specific point of the reduced nitrogen content. They also point out that gains in yield are only short term, due to acclimation. So it seems the only person telling *half* the story-John D-is *you*. You deliberately ignore the half of the story that doesn't fit your agenda. -
Dikran Marsupial at 20:16 PM on 18 April 2011Christy Crock #3: Internal Variability
Gilles@101 There you go again, I am not the one suggesting that the drift is problematic. The need for flux corrections is an indication that there models had inadequacies in exactly the same way that epicycles were and indication that heliocentric and Copernican models have inadequacies. The comparison with planetary motion was a comment on the way that models are developed, I didn't imply in any way that the problems were physically related. It is only your supposition that "large timescale evolutions" actually exist, you have provided precisely zero evidence to support that supposition. The unforced stabilty of the climate seems well established by the paleoclimate record. Can you give an example of a major shift in climate that cannot be attributed to a change in forcing? If not, your argument seems to be as follows: Models with known shortcomings exhibit unforced drift. Therefore the real climate may have unforced drift. Therefore the model projections may be unreliable. That isn't a very convincing argument. Maybe the problem is with your second language issues. In which case, as I suggested you need to spend more time both reading other peoples posts (which you repeatedly appear to misunderstand) and more time writing your posts to explain yourself better (so that others don't misinterpret yours).
Prev 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 Next
