Climate Science Glossary

Term Lookup

Enter a term in the search box to find its definition.

Settings

Use the controls in the far right panel to increase or decrease the number of terms automatically displayed (or to completely turn that feature off).

Term Lookup

Settings

All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Home Arguments Software Resources Comments The Consensus Project Translations About Support

Bluesky Facebook LinkedIn Mastodon MeWe

Twitter YouTube RSS Posts RSS Comments Email Subscribe


Climate's changed before
It's the sun
It's not bad
There is no consensus
It's cooling
Models are unreliable
Temp record is unreliable
Animals and plants can adapt
It hasn't warmed since 1998
Antarctica is gaining ice
View All Arguments...



Username
Password
New? Register here
Forgot your password?

Latest Posts

Archives

Recent Comments

Prev  1760  1761  1762  1763  1764  1765  1766  1767  1768  1769  1770  1771  1772  1773  1774  1775  Next

Comments 88351 to 88400:

  1. More Carbon Dioxide is not necessarily good for plants.
    So we have at least one FACE trial that shows that Rice grown under conditions of increased CO2 will have a decrease of N, on average, of 14%, P by 5%, Fe by 17% & Zn by 28% (according to Seneweera and Conroy, 1997). Ziska et al (1997) have reported a drop in protein content in crop plants when you combined increased temperature & CO2. Although I'm struggling to find a peer-reviewed reference, there is a general belief that warming will lead to a shortening of crop growing cycles, thus resulting in reduced crop productivity. Also, I've read that increased CO2 tends to boost *vegetative* growth at the expense of *reproductive* growth. As was pointed out above, as we tend to eat the reproductive material of most crop plants (like corn, rice & wheat), this is *not* a good thing.
  2. More Carbon Dioxide is not necessarily good for plants.
    I want to be clear that Berényi linked to the original graph and publication in the image hyperlink. However, the graph as presented here was Photoshopped to remove 100 years of predictions that completely contradicted how he presented the information. I consider that deliberate distortion. The graph itself (unnumbered in the Hadley PDF) is something I couldn't find discussion of in that document - I don't know if it's talking about forests, all vegetation, what the sources are, etc., so I don't consider it a great reference in the first place. But much much worse when clipped and distorted.
  3. A Flanner in the Works for Snow and Ice
    Ken Lambert @79, no I am not - and that is a ridiculous accusation. I have taken a conservative estimate of the difference of ice coverage between circa 1979 and circa 2010. I have taken a conservative estimate of the energy flux in that area measured in Watts per square meter. I have multiplied the energy gain measured in Watts per square meter (= Joules per second per square meter) and multiplied it by 60 (60 seconds in a minute), then by 60 again (60 minutes in an hour), then by 24 (24 hours in a day) and then by 90 (three months at 30 days per month). I have then multiplied by the total area. Now you suggest that 60*60*24*90 Watts is "30 to 32 years of heat gain". Absurd!
  4. More Carbon Dioxide is not necessarily good for plants.
    @51 Chris G: "If you pull out a globe, or open Google Earth, and look at where major agricultural areas are now, there are a fair number which will not be readily migrated poleward. Geographic features and political boundaries will make it so that this problem is much more difficult than the base cost of relocating farmers and the cities they are based out of." Yes Chris, I am very much aware of the constraints of migration. Particularly agriculture. However, I was referring to biotopes in general. Canadian boreal forests have soil that is thin, nutrient poor and acidic. Then there's the Siberian permadefrost which will basically become muck, swamps and a million methane bubbling lakes. I believe I can resolve this issue by adding one word to point #4. That word is "mostly". "While deserts increase in size, other eco-zones, whether tropical, forest or grassland will [mostly] migrate towards the poles; shrinking in land area as they do.
  5. A Flanner in the Works for Snow and Ice
    Tom Curtis #77, #78 "That is only 3 to 4 times Trenberth's figure, but Trenberth did not calculate the average amount of energy absorbed in annual (not seasonal) ice melt over 1979, but only over 2004 to mid 2008, over which period there was an average of around 1.8 million square kilometers of additional ice lost relative to 1979." That is your error. You are taking the ice melt area 'relative to 1979' which means that you have 30 or 32 years of heat gain (energy) in your calculated number of Joules. A Watt is a Joule/sec so if you use forcings (energy flux) in Watts you must introduce the unit of time. ie Joules/year - which is what Dr Trenberth is calculating.
  6. More Carbon Dioxide is not necessarily good for plants.
    "KR at 10:06 AM on 18 April, 2011, I am constantly perplexed by claims such as yours that many charts are doctored or not properly referenced, when it is a simple matter of clicking on such charts to go to the original source." Oh, what a surprise-members of the Denial-o-sphere coming to each other's defense. The issue here, John D, is *why* do people like BP & Gilles always choose to clip or modify the charts they post, in such a way as to give a false impression of what those charts are actually telling us? You, too, have a habit of reporting only *half* of a story-like the story regarding your beloved FACE trials. The FACE trials really don't properly mimic what a CO2-enriched world would look like. Even the Horsham Trial only looks at current conditions for rain-fed vs irrigated agriculture. Yet even those people running the Horsham Trial have conceded that increased CO2 leads to a decrease in nitrogen uptake by the plants-& that any gains in biomass are short-term, with acclimation setting in within 2-3 years. Yet you only mention the rather modest "benefits" of the FACE trials-why is that?
  7. More Carbon Dioxide is not necessarily good for plants.
    @44 LukeW: "This post on CO2 is dreadfully simplistic and naive." Simplistic yes. That's what you get with a basic level rebuttal. Naive, I think not. In the Australian context of savanna woodlands increased vegetation in terms of trees will decrease not increase fire. Grass is what makes fire carry in the world's vast area of savanna biomes. "Most detailed crop physiology modellers will now take CO2 fertilisation into account when simulating crop growth. If there is enough water and nutrients growth will be enhanced. At the levels of CO2 enhancement practically experienced in the field is CO2 really having any impact of yield quality?" Please see the video (1:58; also, focus on 2:21) for a global perspective. That is observation as opposed to modeling. "At a whole landscape scale increased CO2 will improve transpiration efficiency and greater water runoff will result." Since I try to be as thorough and detailed as possible, you some of your statements and questions have already been covered in previous posts. As far as water depletion, irrespective of the benefits of transpiration, is concerned; I responded to that in the post right before yours (#43). I responded to the issue in the context of mechanized agriculture. Please refer to the second to last paragraph in that post. "Climate change will have winners and losers. If North America became warmer and wetter - their wheat yields would be boosted considerably, especially with some CO2 turbo-charging. As for more intense rainfall causing greater loss of soils and nutrients - I wonder - there is this thing called soil conservation - contour banks, minimum tillage or zero tillage. Great advances have been made in these areas over the last 40 years." "Winners and losers." Are you referring to plants in general or mankind in a rapidly changing world with famine; infrastructure damage; economic collapse and mass migration? Did I forget wars? As far as advantages in soil conservation, three points can be brought up. First; how much time and extra resources will we have to adapt with? How much time to adapt to worsening conditions for crops and socio-economic situations? IMO, expect serious trouble beginning this decade and escalating from there on. Second; overwhelming flooding like Pakistan and Australia will overwhelm the positive effects of soil conservation. Pakistan, for example, was so inundated over 20% of its landscape that some farmers could not even distinguish their former land from the rest of the terrain. That was due to the massive floods changing the landscape altogether. Third; low and zero tillage are at odds with mechanized agriculture, as far as I know. "What could have been mentioned at the other end is that CO2 can increase frost sensitivity (deniers would chip in here and exclaim it will never frost again)." That should be mentioned in a more advanced post. It is simply too much detail for the basic level reader to digest. It's best not to overload them with too much information. I feel I've already done that to a certain extent. "Anyway the case for winners and losers needs to be made. At nation state level, land use, biome, and ecological patch level. The article here is far too simplistic." The summation above has been covered in the previous statements IMO we will need a drastically different civilization to adapt to CAGW. A network of self-reliant villages, numbering no more than 500 persons each; is what I envision. But that's a different story.
  8. Daniel Bailey at 11:19 AM on 18 April 2011
    More Carbon Dioxide is not necessarily good for plants.
    @ Albatross and KR: 'Tis a Travesty the Tricks employed by the Deny-O-Sphere to Hide the Decline...
  9. The e-mail 'scandal' travesty in misquoting Trenberth on
    Alec Cowan #133 Alec, stop being coy and tell us all what is wrong with the K&D paper.
  10. More Carbon Dioxide is not necessarily good for plants.
    May I second Adelady? Nature Does Not Care in the slightest about your survival, or any other species survival for that matter. If you survive - great. If you don't - equally great. Organisms comfortably adapted to a particular set of surprisingly stable conditions poke those conditions with a sharp stick at their peril. (How this can be done in the name of 'Conservatism' is beyond my comprehension - and parody!) Liebig's law puts the lie to the idiot 'CO2 is plant food - therefore more must be good' mantra full stop. You only have to demonstrate any substantial exception to such a glib fallacy in order to disprove it. If the initial meme is inane quibbling that the anti-meme is insufficiently nuanced is just captiousness. You can get too much of a good thing; quibbling about the complex (indeed, Chaotic) boundary of this 'too much' as if this somehow invalidates the general principle is pointless at best. 'Yellow doesn't exist because you can't define the point in the spectrum at which it becomes orange' is not a valid argument.
  11. More Carbon Dioxide is not necessarily good for plants.
    KR at 10:06 AM on 18 April, 2011, I am constantly perplexed by claims such as yours that many charts are doctored or not properly referenced, when it is a simple matter of clicking on such charts to go to the original source. I do it as a matter of course. If I can do it, how come others cannot. What is the problem, lack of research skills or what?
  12. More Carbon Dioxide is not necessarily good for plants.
    I was thinking there are at least two ways of thinking of this issue. In the post above, mostly the discussion is about how plants respond to changing conditions. The other way is to think of it as where conditions exist. Expanding on item #4: Poleward movement of terrestrial surface isotherms is expected to average between 3.8 km and 5.9 km per year if current trends of global climate change continue (1). If you pull out a globe, or open Google Earth, and look at where major agricultural areas are now, there are a fair number which will not be readily migrated poleward. Geographic features and political boundaries will make it so that this problem is much more difficult than the base cost of relocating farmers and the cities they are based out of.
  13. More Carbon Dioxide is not necessarily good for plants.
    villabolo at 09:45 AM, just FYI the other thread was available from the time you first made it. I noticed it then,but didn't have time to respond, only earlier seeking it out again to follow up. Perhaps you should have it removed entirely as it only serves to clutter and confuse. The only link you provided is to an abstract regarding, IIRC, a laboratory study. I believe I have read some of that paper somewhere previously. However, given we are talking about the real physical world, laboratory studies are of limited value. At the very least it should be the results of FACE trials that you are referencing as these provide the closest data simulating future real world conditions. But more important than that they are the only means by which modeling based on laboratory experiments are able to be validated. It appears that the FACE trials indicate that the results produced under real world conditions differ from the expectations of the modeled laboratory projections, requiring the models to be retrained against the results obtained under FACE conditions.
  14. More Carbon Dioxide is not necessarily good for plants.
    KR, Smile. Good sleuthing. There goes BP'S already troubled credibility. I hope that people following this thread note that this is the kind of thing that climate scientists and others who understand AGW to be a concern repeatedly come up against. The 'skeptics' demonstrate highly questionable ethics, yet repeatedly falsely accuse others of same. Again, this is not so much about where things stand now, but where we are headed if we continue on this path consumption.
  15. Clouds provide negative feedback
    Sphaerica (RE: 22), "1) Present your own model more clearly. You skip steps, make leaps, then get frustrated when other people can't figure out where you get your numbers from. You even claimed that you didn't have a model!" What specifically do you want me to explain? I agree with the moderator that a lot of this has been covered in previous discussions, but if you ask any direct question, I'll do my best to answer it. At any rate, I'd like to get back on topic with a question: If clouds are not the primary mechanism modulating the energy balance, and are instead acting to greatly amplify relatively small temperature changes, then what is the primary mechanism controlling the energy balance of the planet?
  16. Clouds provide negative feedback
    As far as I can see RW1 believes that you can infer feedback relationships from the Trenberth state diagram (ie the comments about gain) and then use these no.s to project what the diagram would look like for say doubled CO2. When the no.s dont accord with those calculated properly, then RW1 claims physics is wrong.
  17. More Carbon Dioxide is not necessarily good for plants.
    Moderators - What are the ethics of a carefully clipped chart (pretty obviously edited) without attribution?
    Moderator Response:

    [DB] Given that less than 10% of all readers ever click on an obviously provided link, when said hyperlink is incorporated into an expandable thumbnail (Admission: I hyperlink scaled thumbnails for brevity sake; but I do not only present PART of the original image) with the only way of knowing it IS hyperlinked is to mouse over it/move the cursor over it...you tell me.

    Not warning the reader that the enclosed graphic is an enlarged, windowed version of a much larger graphic certainly opens up the reader to the possibility of taking the totality of the graph out of its intended context.

    In like fashion, it certainly opens up the poster of the questionably presented graphic to many, many questions...

  18. More Carbon Dioxide is not necessarily good for plants.
    Berényi Péter - That's a fascinating chart, Berényi. Why did you clip it? This is from a set of Hadley Center forest predictions, discussing climate change effects on forests. Unfortunately, there is no discussion of that chart in the PDF. One interesting factoid from that PDF - during the 2003 heat wave in Europe, crop productivity dropped 30%. Climate change doesn't seem to be good for crops...
  19. More Carbon Dioxide is not necessarily good for plants.
    @41 Albatross: "One of my main concerns about this post is that there was not meat in terms of referencing the scientific literature-- but some mistakenly take that to mean that such support is missing in the literature." Albatross, John C previously stated, in response to someone with your own concerns on references, that it was not necessary for a Basic Level post to provide such references. The articles cited in the illustrations do provide such sources. In any case, I'll be adding extra primary source references as time allows; but there is no need to elaborate in the main text due to its basic level.
  20. More Carbon Dioxide is not necessarily good for plants.
    @39 Johnd: "villabolo at 06:59 AM, strange you didn't notice the other thread as you have 3 separate posts in it." I did post on what I assumed was a blog post that had not been officially turned in a post for public view. As I said, this is the first post I noticed today, when I went to home page. I assumed that anything on this post would supersede any previous posts. Sorry for any misunderstandings. As for declining nutrition in wheat, mentioned in my rebuttal above, I provided a link. As to other comments on nutritional deficiencies due to mass produced agriculture (Non CO2 related), that was an off topic comment in response to the claim that FF based agriculture is "advanced". I'd rather leave that particular issue at that. Right now I'm backed up with two other responses as well as personal chores, so I can't respond to every question; particularly if they're not directly in reference to CO2 issues.
  21. A Flanner in the Works for Snow and Ice
    Ken Lambert @77:
    You say: "Therefore there is need to divide the 1.51*10^21 Joules by 32. That is the additional amount of energy each summer that would not have been absorbed except for the reduced sea ice area." That is precisely my point.
    Sorry, that was a typo. I intended to write, "Therefore there is no need to divide the 1.51*10^21 Joules by 32."
  22. A Flanner in the Works for Snow and Ice
    Ken Lambert @76, if the additional melt had proceeded smoothly over the years (which is not true), then the arctic ocean would have absorbed 4.7*10^19 Joules more in the summer of 80 than in the summer of 79; and 9.4 more Joules in the summer of 81 than in the summer of 79, and so on. However, in the summer of 2010 it absorbed more than 1.51*10^21 joules more than it absorbed in the summer of 79. If you were to calculate the average additional energy flux in the years between 1979 and 2010, the figure would be 7.55*10^20 assuming (incorrectly) an even progression) or perhaps half that given that the loss of summer sea ice extent between the early 1980's and 2006 was only about 1 million square kilometers. That is only 3 to 4 times Trenberth's figure, but Trenberth did not calculate the average amount of energy absorbed in annual (not seasonal) ice melt over 1979, but only over 2004 to mid 2008, over which period there was an average of around 1.8 million square kilometers of additional ice lost relative to 1979. Hence the additional amount of energy absorbed in that period is conservatively estimated as 1.8/2*1.51*10^21 = 1.359*10^21. As it happens, Flanner did his calculations on the average over the same period, so I should probably accept 1.35*10^21 as my conservative estimate rather than the figure I have been using which includes an additional two seasons of extreme ice melt.
  23. The e-mail 'scandal' travesty in misquoting Trenberth on
    @Ken #131 I forgot. Why have you supposed that the figure in #128 was the only one? Did you want that a group of teenagers evaluated the whole planet? The whole oceans were covered by different groups. Those teenagers understood it, why don't you? There is also another exercise covering different months of a year. Every slice had its own tremendous variability and you can see that in Figure 1 and in the Argo site how all of them amount to a variable total. That is what I'm asking you to comment from figure 1 and by those means that you show a comprehension on the subject.
  24. The e-mail 'scandal' travesty in misquoting Trenberth on
    @Ken #131 You're just repeating yourself, Ken. Why don't you quote exactly every part of Knox & Douglas where they state clearly that the ocean layer is other than 0-700 metres regarding figure 1 and their calculations using those 4 methods? Do that and we'll continue to talk because it looks like you "want" for it to be "the oceans". It looks to me like you see Ocean Heat Content and a flat or slightly negative trend line together and feel a heartbeat rush "That's it!". Read it again, carefully. Then we can move to the others studies and later come back to the cooling periods -the real ones-. That's where the travesty is. Should I conclude that you see Knox & Douglas' figure 1 and have nothing to comment?
  25. Solar Hockey Stick
    @Berényi Péter #75 It looks from your last graphic that UV-A radiation doesn't reach farther than blue light does. It looks like your UV heating is not much different of Blue Light heating. Reading the last figure we got some 1.3 x 10-4 cm-1 for blue light so we keep some 99.987% of light intensity once we penetrate one centimetre in the water -fresh, crystal clean water-. Some 87.8% of this blue light reaches 10 metres deep. Some 27% reaches 100 metres and only 2% reaches 300 metres. But we know we are not talking of distilled crystal clear water but some water with one ion of an heterogeneous kind for each 50 water molecules. Where is the information about how different wavelengths do in filtered sea water? Besides, does somebody remember having sailed far from the shore an having seen clearly the silhouette of other ships' hulls underwater. Sea water is pretty cloudy as it's full with life and every kind of particles. So almost nothing of blue light reaches 100 metres, nor UV-A does, what begs the question, Berényi Péter, what are you up to? Why are you telling us "this kind of radiation can penetrate into the ocean (down to several hundred meters) and deposits its energy there as heat"? Don't you realize most of the energy got converted to heat in a few dozen of meters and almost nothing goes deeper that 100 metres? Why do you talk as if a mermaid go several hundred metres down and lay an egg, and egg containing a secret? Why are you saying that a thousandth of the energy of a band that accounts for 2% of total radiation is a better measurement of what? Didn't you realize that your penultimate graphic tells that 60% of the radiation in your precious UV-A band doesn't even reach the surface?
  26. More Carbon Dioxide is not necessarily good for plants.
    This post on CO2 is dreadfully simplistic and naive. In the Australian context of savanna woodlands increased vegetation in terms of trees will decrease not increase fire. Grass is what makes fire carry in the world's vast area of savanna biomes. Most detailed crop physiology modellers will now take CO2 fertilisation into account when simulating crop growth. If there is enough water and nutrients growth will be enhanced. At the levels of CO2 enhancement practically experienced in the field is CO2 really having any impact of yield quality? At a whole landscape scale increased CO2 will improve transpiration efficiency and greater water runoff will result. Climate change will have winners and losers. If North America became warmer and wetter - their wheat yields would be boosted considerably, especially with some CO2 turbo-charging. As for more intense rainfall causing greater loss of soils and nutrients - I wonder - there is this thing called soil conservation - contour banks, minimum tillage or zero tillage. Great advances have been made in these areas over the last 40 years. What could have been mentioned at the other end is that CO2 can increase frost sensitivity (deniers would chip in here and exclaim it will never frost again). Anyway the case for winners and losers needs to be made. At nation state level, land use, biome, and ecological patch level. The article here is far too simplistic.
  27. More Carbon Dioxide is not necessarily good for plants.
    @24 Steve L: "This is an interesting topic. I get the feeling that several aspects may have been glossed over (as necessary for a blog post) -- one of these is the conclusion that more water will be necessary for plants in a higher CO2 world. Because the stomata won't need to be open so long (due to the higher CO2 availability), there will be less evapotranspiration per carbon molecule fixed. SteveL; It's refreshing to have a meaningful and rational question to respond to. No, it's not so much glossing over as it is keeping the post both on a basic level as well as brief (You can see how long it already is). However, to answer your question from a non-scientist's view, let me make some inspired attempts. Even if plants should become more efficient in water usage they are still likely to require more water. Perhaps in lesser proportion compared to other factors but more nonetheless. Likely to be of more importance is the increase in soil evaporation. This would effect agriculture due to the soil being exposed. Also when the temperature gets too hot for the plant's basic metabolism, aquifer fed sprinklers would have to be used to cool them down. Aquifers are getting depleted throughout the world. Metaphorically speaking, there is a spider web pattern of effects when you pull just one thread.
  28. More Carbon Dioxide is not necessarily good for plants.
    "How do you explain that it seems to be *universally* unfavorable, everywhere?" Unfavorable? Only if you've got some vested interest in things being much as they have been for the last 10,000 years or so. Many millions of years ago, lots of little critters in a different atmospheric arrangement produced a gas that was poisonous to the biota of the time. In the end, oxygen wiped out a whole "nature" that had developed relying on little or no oxygen. In its place, we got the beginnings of the atmosphere that suits us and the other plants and animals that survive and thrive around us. Nature. Does. Not. Care. About anything. It's like a computer or the internet. It is just a set of processes and linkages that work regardless of what we would call the content. A computer does not know or care if it is used to create beautiful art or write a vile book or play mindless games or run a payroll or spread a 'virus' destroying the hard work of millions of people. It just follows its own rules. If something happens to damage or destroy some plants or animals, 'nature' does not know or care that its processes may take thousands or millions of years to establish a new set of successful items. Its got all the time in the world. Literally. We are the only ones that care whether our own lives or the lives of our descendants will be comfortable and successful or difficult and miserable. We are the only ones capable of caring whether the same considerations affect people we'll never know and plants or animals we will never see.
  29. Clouds provide negative feedback
    21, RW1,
    Where does the difference between "established physics" lie ? This is what I don't understand.
    And this is the crux of your problem. You need to do two things: 1) Present your own model more clearly. You skip steps, make leaps, then get frustrated when other people can't figure out where you get your numbers from. You even claimed that you didn't have a model! 2) You are the outlier. You are the one with the unconventional point of view. The burden is yours to explain your position, but more importantly to study (as the rest of us have) to learn what the mainstream science says. If you can't see the difference between what you put forth, and what everyone else already understands, the burden falls upon you to educate yourself to eliminate that gap. You can't just demand that everyone answer your questions, when you don't demonstrate a clear grasp of the established science, or when you make incorrect statements that clearly are not in line with the established science, and yet even when this is pointed out, you can't see the difference, stomp your feet, and get flustered. You can complain that something is incorrect if you can demonstrate that you understand things, and can yourself clearly explain where your position diverges. You cannot, on the other hand, complain that you don't know why people can't answer your questions, and yet refuse to consider other points of view yourself. You also should not be adopting the tone that you are right, all of main stream climate science is wrong, and so everyone else owes it to you to prove to you that you are mistaken. Like it or not, you are the outlier. If you want to "sell" your position, you need to do that, by convincing other people, not by demanding that they convince you.
    Moderator Response: [muoncounter] RW1 has explained his position in considerable detail on the Lindzen and Choi thread; it is not necessary to start that up again. He is correct in expressing an interest in staying on topic.
  30. The e-mail 'scandal' travesty in misquoting Trenberth on
    Alec Cowan #130 "Why? Is some cherry-paper picking out there? Some kind of "editorialized" line of evidence? The papers I was referring in a previous comment are related to the travesty as Trenberth meant it. The papers you picked are related to the a supposedly independent line of evidence "confirming" the 'climategate' paraphernalia." The Knox and Douglas paper was published in Aug10 which showed that 2003-08 data for OHC content was flat or slightly negative (cooling)for the top 700m and *deep ocean* of approx +0.09W/sq.m (Purkey & Johnson). The paper cites five Argo studies for 0-700m OHC by Willis, Loehle, Pielke, Knox & Douglas show **negative** OHC change, while von Schukmann (0-2000m) is the outlier showing +0.77W/sq.m. I note that K&D quoted Willis (a private communication) as a reference in the Aug10 paper. This is pretty recent information. I would like know if the Knox & Douglas paper has been contradicted or its findings overturned by more recent studies. BTW all these numbers quoted in the above papers are 'global'. You can highlight parts of the oceans which are heating or cooling, but what counts about 'global' warming are 'global' numbers.
  31. More Carbon Dioxide is not necessarily good for plants.
    Villabolo, There is much material out there to satisfy the "concerns" raised by the 'skeptics' regarding the nutritional content being diminished for doubled or trebled CO2 levels. One of my main concerns about this post is that there was not meat in terms of referencing the scientific literature-- but some mistakenly take that to mean that such support is missing in the literature. Ironically enough, the only link that you provide in the body text (at point number 3 in your post) is about diminished nutritional quality in some staples, in this case wheat. I'm certain that the "skeptics" do not even bothering reading these posts, they see the title and launch into obfuscation mode.
  32. Glenn Tamblyn at 08:25 AM on 18 April 2011
    More Carbon Dioxide is not necessarily good for plants.
    Several additional points from things I have read in the past - sorry know references, just memory. Increased CO2 levels can result in reduced numbers of Stomata on leaves - with more CO2 available they don't need as many to supply the same metabolic rate. Paleoclimatologists use stomata counts on fossil leaves as a method of estimating past CO2 levels. Stomata are used for evapotranspiration so this may reduce water loss, but this also provides the plants principle source of cooling, so changed stomata count may impact a plants ability to thermo-regulate - an issue in a hotter and certainly more variable climate. Temperature limits are important to plants. They can do quite well up to some temperature limit then declines markedly - the tree-line on any mountainside is the most obvious example of this. With more CO2 available a plant may be able meet its 'food' needs with less consumption of its resources freeing it up to devote more resources to other functions such as protection from predators through the production of more toxins. I believe increased toxin levels have been reported in Cassava. Might we see increased caffeine levels in coffee & tea? Just because a plant may be able to produce more biomass from increased CO2, that does not automatically mean that this increased biomass will manifest as increased yields of the crops we eat. Our food supply is sourced predominantly from the reproductive parts of the plants. Just because a plant is doing better overall does not mean that it will therefore increase its reproductive activity. A common trait is that plants go into increased reproductive activity, more flowering etc when under stress. If the plant is thriving it might devote more resources into enhancing its own survival rather than reproduction. There could even be a reduction in yield from some plants because of this. Finally the response of a plant species to an environmental change can be two-fold: Adaptation to the changed environment via changes to its metabolism or Migration to remain within its preferred environment. The capacty of plants to adapt to an environmental change depends on whether they have the metabolic pathways and behaviours that allow that change or whether they can evolve new traits as a response. If it doesn't have the pre-existing metabolic/behavioural response availabe, then evolution is its only viable response. Which then raises the question of speed of adaptation. With the rate of CO2 change being nearly unprecedented in Earths history, how fast a plant can adapt to a change may its key survival problem. Annuals such as grains may fare better here than larger long lived species that take years to reach sexual maturity. So evolutionary rates of change could have huge impacts on the species mix of ecosystems, with all sorts of flow on effects. As far as migration is concerned, this again depends on mechanism and speed. Wind blown seeds that can go huge distances allow rapid migration. Seeds from fruit that drop near the parent only permit very slow migration. And just because migration speed may be sufficient to keep pace with climate shifts, that doesn't mean the other aspects of the environment they need will be available, particularly soil characteristics. And finally, plants face a predator that not only predates them for food, but unusually predates them very effectively if they migrate, just because they are migrating. Us. We call them weeds and kill them. So given the range of possible impacts on plants due to CO2 rise and temperature change, from individual plant composition to ecosystem structure, the fact that some plants may reap some benefits from increased CO2 is far more likely to be overwhelmed by the diversity of negative adaptation pressures for ecosystems. And since some of these ecosystems are critically important to us - we call them farm paddocks - CO2 increase is far more likely to be a negative than a positive for our food supply.
  33. A Flanner in the Works for Snow and Ice
    Tom Curtis #75 You say: "Therefore there is need to divide the 1.51*10^21 Joules by 32. That is the additional amount of energy each summer that would not have been absorbed except for the reduced sea ice area." That is precisely my point. The annual (or per summer) increase in heat absorbed by your calculation is therefore 0.49E20 Joules/year. This compares with Dr Trenberth's 1E20 Joules/year for Arctic Sea Ice comtribution to the global heat imbalance budget of 145E20 Joules/year (equal to 0.9W/sq.m globally)
  34. More Carbon Dioxide is not necessarily good for plants.
    villabolo at 06:59 AM, strange you didn't notice the other thread as you have 3 separate posts in it. Anyway are you going to address the matters I repeated in this thread in "johnd at 05:17 AM" with connection to your assertions, particularly to quantifying your claims about declining nutritional values of foods grown for human consumption, past present and future.
  35. More Carbon Dioxide is not necessarily good for plants.
    Strange evolution we have, don't we? The plants are not optimized for a 280ppm level of CO2 imposed to them during millennia, but for the 395ppm actual one and they have yet more to give as they are expecting the level to reach 500, 600, any advance on 700ppm? just to thrive. Even stranger evolution: all plants will equally thrive, the big ones, the small ones, even in lichens, the photosynthetic partner will increase the pace and the mycobiont will follow singing "heigh-ho! heigh-ho! ..." ... it will be heaven in earth!! Alleluia! The fact is that gene pools in every species contain most everything it's necessary to face changes provided there are not so many things changing at the same time and given enough time. Is that factor being taken into account? Everything is good if CO2 raises to 1000ppm in 10,000 years? 1,000 years? 100 years? 25 years? How come any underground line brings me home? How does a species to know that it needs to adapt to 800ppm CO2, 5°C more and dryer conditions, or just adapt to 800ppm CO2 and move from Baja California to Anchorage? Will it have time enough to move as in previous occasions? Do Tijuana, San Diego, Los Angeles, San Francisco, Portland, Seattle and Vancouver let it move naturally?
  36. More Carbon Dioxide is not necessarily good for plants.
    @ Gilles "CO2 has increased, and agricultural production has increased as well." Yes, but most likely the increase in CO2 is not responsible (again see Liebig's law of the minimum). But more to the point, as was stated in the second paragraph of this post "Too much of a good thing can be a bad thing." The effects on climate by CO2 over the past100 years have been small compared with what we expect for the next 100 years under BAU. Which means that the correlation you are so fond of is not likely to continue. Or to summarize, no amount of CO2 will make the Sahara green.
  37. More Carbon Dioxide is not necessarily good for plants.
    @30 Gilles: ""The FF-powered tractor has caused a tremendous increase in agricultural productivity in the last 100 years. FF have also allowed for the cheap production and delivery of pesticides and herbicides, advanced seeds (I should say "advanced" when I think of Monsanto), and advanced agricultural machinery. I think--and I'm just guessing here (sorry scientists)--that such things far outweigh any currently theorized positive effect of CO2 on plant growth where agricultural productivity during the 20th century is concerned." This is off topic so my response is going to dead end with this post. Our agriculture is definitely not"advanced" but destructive. 1. Soil erosion of six feet in what used to be prairie. This is due to soil exposure that monoculture inevitably creates. 2. The quality of food has been going down for decades. It's been tested for nutrient levels for that long. 3. As far as pesticides and herbicides are concerned, they are overused and would not even be need with truly advanced horticulture. Do some research on Permaculture, Gilles. It is self fertilizing like nature. Why deplete oil reserves that should be conserved for plastic production? Permaculture is also, by design, very resistant to pests. It eliminates soil erosion and it provides optimum quality food by restoring and increasing the fertility of our depleted soils. You are operating from the assumption tat this is the best of all possible worlds. It is not and FF is actually contributing to its demise even when you take GW out of the picture.
  38. David Evans' Understanding of the Climate Goes Cold
    dana1981 at #24 Crikey. I really must learn to stop underestimating the stupidity/sneakiness of the "sceptics". You mean the figure Evans used was him saying that if Australia achieved zero emissions from tomorrow that the equilibrium temperature in 2050 would be 0.015 deg less than it otherwise would have been? In other words he meant it would be a tiny bit less hot, not cooler? That really is twisted rhetoric that looks to me like it was crafted to misdirect the listeners.
  39. More Carbon Dioxide is not necessarily good for plants.
    I agree with Alec @34, and I'd recommend taking it further, if one if going to post images at SkS two things: 1) They should be cited/sourced and a link to the original report or journal paper should be provided. Context is very important. 2) They should not be rooted by a bizarre site like this as BP's image is.
  40. More Carbon Dioxide is not necessarily good for plants.
    @Berényi Péter #26 I'm saying it again: Add 24 dollars and you'll get Manhattan. Where did you get that figure? "Source: Based on ...."? Can you explain how come from 1860 to 2010 that the content of carbon in soils increased? What kind? Where? (Location, level) How come the value of carbon in soils increased when agriculture by using chemical fertilizers and irrigation has obtained crops in a soil increasingly impoverish in humus so the black rich soil in years back has become nowadays that brownish or yellowish thing. A group of people debated some months ago (in Spanish) about this general subject and information was presented about some 6GTons of Carbon lost from soils just from the Pampas, and some other +2Gtons lost from the Chacos during the last century, just in part of my country -those regions totals some 0.7% of emerging lands-. In vegetation, the lost of mass in the Chacos is enormous and maybe we can estimate it in some 0.4 to 0.6 GT of Carbon (35 million of hectares of 20-25 meters high forests with very old trees has been reduced to grassland, bushland and seasonal agriculture). Again, are the soils becoming increasingly dark by humus or the Carbon is kept in some strange chemical process? Could you explain. Your image is very hard to believe. Some 70GT of increment in Carbon content for some roughly 100 million square kilometers of emerging lands -excluding Antarctica, Greenland, deserts, inland waters, rocky places, and the like- is some 0.7kg per square metre, so a volume of some 2-3-4 litres of humus has been add to every m2 of black to reddish soil, dry bald grasslands and under human pavement. How come? Can you elaborate? Can you state the source and why you judged it to be appropriate for this site and for this subject?
  41. More Carbon Dioxide is not necessarily good for plants.
    @30 Gilles: "You're saying that increased atmospheric CO2 caused the increases in 20th century agricultural productivity? " Noooo, I'm just saying it didn't prevent it." 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? It's not likely to be a gradualistic or linear incline. It could be like the proverbial straw that broke the camel's back. 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. Of course, those levels are doing nothing but going up.
  42. More Carbon Dioxide is not necessarily good for plants.
    @5 Gilles: "AFAICS, the initial posts contains a short list of possible reasons that could go worse. This is neither exhaustive, nor limitative. There is no figures associated. No possibility of doing any budget. No experimental validation on a global scale. I can't see how to draw a general conclusion from that .." That is why we have Intermediate and Advanced levels, Gilles. As far as experimentation on a global scale, why the Hades would that be needed? We can learn all we need to know from a few experiments and draw general conclusions as to what would happen globally.
  43. More Carbon Dioxide is not necessarily good for plants.
    @ 17 Johnd: Whats going on here? I earlier posted a response to the recently created (April 14th) "CO2 is plant food" thread, and instead of responding, the author then duplicates his claims made there in a this brand new thread. I know there is a redundancy Johnd but that is not due to anything I did. This is the first thread that I noticed, so I've been here all along. If there's a problem you can take it up with one of the moderators or John Cook.
  44. More Carbon Dioxide is not necessarily good for plants.
    "You're saying that increased atmospheric CO2 caused the increases in 20th century agricultural productivity? " Noooo, I'm just saying it didn't prevent it. "The FF-powered tractor has caused a tremendous increase in agricultural productivity in the last 100 years. FF have also allowed for the cheap production and delivery of pesticides and herbicides, advanced seeds (I should say "advanced" when I think of Monsanto), and advanced agricultural machinery. I think--and I'm just guessing here (sorry scientists)--that such things far outweigh any currently theorized positive effect of CO2 on plant growth where agricultural productivity during the 20th century is concerned." and yet the idea is to suppress FF ... to avoid CO2 to hinder productivity ... ??
  45. More Carbon Dioxide is not necessarily good for plants.
    @1 Gilles: " wonder why Nature has managed to make an increase of average temperature bad for everything. Isn't it quite unlikely ?" "Why am I not surprised that Gilles would be the first commenter on my post? No, it's not going to be bad for everything. Just those things that survive. It'll only take a few tens of thousands of years for evolution to enable plants that don't fair well with increased CO2 (Assuming they don't become extinct for ther AGW related issues). "especially for agriculture,it is quite weird because each plant has a favorite biotope, so the productivity cannot be a universal decreasing function of the local average temperature. So it must be somewhere optimal. But changing temperature should only displace the location of the optimum. Well it could be that this displacement is unfavorable, but also it could be the opposite. How do you explain that it seems to be *universally* unfavorable, everywhere? and if not, how can you properly compute an average trend, and know whether the benefits are larger than drawbacks or the opposite ?"(Underlining mine) You seem to be on both sides of the fence as to the favorability/unfavorability of biotope shifting on agriculture. At least we agree that changing the temperature will shift the location of where the crops would grow (optimally, of course). It's real simple. How many 100s of millions of people are going to be migrating northward (in a civilized manner, of course)? "you seem to possess some kind of science I'm totally ignoring ...." Science? This is actually in the realm of common sense deductions based on the conclusions of science.
  46. More Carbon Dioxide is not necessarily good for plants.
    Gilles: "Excuse me, but am i wrong or in the past century, CO2 concentrations, temperature, and agricultural productivity have all increased together ? is it not a definite proof that it cannot always be true that increasing CO2 will be bad 'on balance'?" I'll bite by stating the obvious counterargument: You're saying that increased atmospheric CO2 caused the increases in 20th century agricultural productivity? Unintentionally, of course, you are correct. The FF-powered tractor has caused a tremendous increase in agricultural productivity in the last 100 years. FF have also allowed for the cheap production and delivery of pesticides and herbicides, advanced seeds (I should say "advanced" when I think of Monsanto), and advanced agricultural machinery. I think--and I'm just guessing here (sorry scientists)--that such things far outweigh any currently theorized positive effect of CO2 on plant growth where agricultural productivity during the 20th century is concerned.
  47. More Carbon Dioxide is not necessarily good for plants.
    Vegetation was carbon-free in 1860 ???
  48. Berényi Péter at 06:34 AM on 18 April 2011
    More Carbon Dioxide is not necessarily good for plants.
    "Increasing CO2 levels would only be beneficial inside of highly controlled, enclosed spaces like greenhouses". I see. This is why global carbon content of both soil and vegetation is increasing exponentially during the last 150 years. In spite of widespread destruction of woodland. Sounds plausible.
    Response: [DB] Those wishing to see the original, in-full-context version of BP's above graph can find it here: http://maps.grida.no/go/graphic/carbon-stocks-trends-and-projections-compared-to-1860.

  49. More Carbon Dioxide is not necessarily good for plants.
    "Increasing CO2 brings with a very large number of changes. Some are good, and some are bad. But the best estimates at quantifying the good and bad show that the bad is far greater than the good." It's just about plant growth here - and it's not "scenarios", just known facts :CO2 has increased, and agricultural production has increased as well.
  50. More Carbon Dioxide is not necessarily good for plants.
    This is an interesting topic. I get the feeling that several aspects may have been glossed over (as necessary for a blog post) -- one of these is the conclusion that more water will be necessary for plants in a higher CO2 world. Because the stomata won't need to be open so long (due to the higher CO2 availability), there will be less evapotranspiration per carbon molecule fixed. At least, that's one hand-waving argument. Has this been worked out in detail?

Prev  1760  1761  1762  1763  1764  1765  1766  1767  1768  1769  1770  1771  1772  1773  1774  1775  Next


The Consensus Project Website

THE ESCALATOR

(free to republish)


© Copyright 2024 John Cook
Home | Translations | About Us | Privacy | Contact Us