Recent Comments
Prev 2315 2316 2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329 2330 Next
Comments 116101 to 116150:
-
Chris G at 12:24 PM on 1 July 2010What is Global Warming and the Greenhouse Effect?
#67, I believe you are correct - distance from peak to trough, or some harmonic thereof. Sounds right. -
Doug Bostrom at 12:17 PM on 1 July 2010CO2 is Good for Plants: Another Red Herring in the Climate Change Debate
Perhaps the next time anyone visits a supermarket and salivates over the well grown fresh produce, and admires the beautiful flowers, just check out how much of what has been admired, or has been put onto your dinner plate in recent decades has been grown in an enriched CO2 environment. Drawing on your expertise, would you please produce some statistics on what we might expect in that department, John? Typically speaking, when I visit my grocery here on the West Coast of the US, what might I expect to see in terms of fruit and produce grown as you imply is common? Depending on the season we typically in a week purchase zucchini, celery, lettuce, tomatoes, potatoes, broccoli, onions, garlic, asparagus, apples, plums, peaches, bananas plus of course other vegetables and fruit. Of the foods I've named, what percentages would I expect to have been grown in enhanced C02 environments? -
Marcus at 12:14 PM on 1 July 2010CO2 is Good for Plants: Another Red Herring in the Climate Change Debate
Wow, what an incredibly long post to say almost *nothing* of value John D. You keep banging on about how *wonderful* the FACE trials are in showing that increased CO2 is a good thing, yet the Horsham trials you rely on show that-even in relatively optimum conditions (in terms of water & nutrients)-there was no significant improvement in grain yield for most varieties, a significant decline in protein yield & an increased demand for nitrogen by plants grown in the enhanced CO2 conditions. As nitrogen is one of the biggest costs facing farmers, this hardly represents GOOD NEWS for the farming community-which is probably why the investigators themselves are so circumspect about their findings-especially given that they were starting to see acclimation just a couple of years into the trial. Given that CO2-induced warming is also expected to cause declines in rainfall, then the prospects for enhanced agricultural output in an enriched CO2 world are looking far grimmer than you'd have us believe. The fact, Mr D, is that until you're prepared to provide more substantial REFERENCES to back up your claims, then people will dismiss you as yet another denialist who gets all his (mis)-information from Monckton et al. -
johnd at 11:53 AM on 1 July 2010CO2 is Good for Plants: Another Red Herring in the Climate Change Debate
villabolo at 11:00 AM, I doubt that Monckton is the originator of the CO2 is food for plants "meme". The technique has been in commercial use for decades and is well understood by agricultural experts. It is only the focus on CO2 atmospheric levels rising that has over the last couple of decades caused them to conduct trials to see if what was being done artificially by commercial operators will be replicated under real world conditions. -
johnd at 11:44 AM on 1 July 2010CO2 is Good for Plants: Another Red Herring in the Climate Change Debate
Rather than simply taking the quick look at the science behind the argument as the author believes is all that is necessary, perhaps a detailed study of the real world, and the real world trials, such as the FACE trials, which are not mentioned, that replicate projected growing conditions, including enhanced atmospheric CO2, higher temperatures and lower moisture levels would be even more enlightening. Perhaps even looking at the results of trials that studied how plant growth responded to depleted CO2 levels would bring even better understanding as to the central role CO2 plays as a growth regulator. The arguments against increased CO2 being a positive for plant growth seems to be based on a belief that the current balance of inputs that plants require is optimum, each in the correct ratio. Commercial greenhouse growers know that that is not correct. Even if they provide sufficient warmth, nutrients and moisture, the full growth potential is not achieved until the CO2 levels are increased to optimum levels as well. Perhaps the next time anyone visits a supermarket and salivates over the well grown fresh produce, and admires the beautiful flowers, just check out how much of what has been admired, or has been put onto your dinner plate in recent decades has been grown in an enriched CO2 environment. The examples of the negative aspects only illustrate a lack of appreciation of the real world. What weeds in agricultural crops love even more than CO2 is nutrients, especially nitrates, and most cropped land has been stuffed full of nutrients. One of the biggest inputs into cropping is weed control, and any competent farmer is gradually reducing the weed seed bank, with genetic modification helping produce crop varieties that are more and more resistant to herbicides. Whether in the past, now or in the future, any farmer who has not overcome the weeds before the crop is planted will not be viable for very long. From an Australian perspective, over the last 50 years, the amount of cereals produced per acre has risen to nearly 3 times the previous level. It is anticipated that the same increase can occur again over the next 50 years even allowing for climate change. That means that the area of weeds that need to be controlled is dramatically decreasing for the same amount of food harvested. That seems more like a positive rather than a negative. As far as the supply of nutrients go, irrespective of any other factors, to produce more food, more nutrients are required to be put into the growing system, that is a basic truth. If the argument is made that the supply of nutrients will not allow the increased growth due to CO2 fertilisation, then there will also not be enough nutrients to support increased food production even if CO2 levels remained constant, or even fell. Being able to put more nutrients onto a smaller unit of soil to produce even higher yields is a positive both for efficiency of nutrient usage and application. OT a bit, but the biggest challenge is that for every 20,000kj per person per day that is produced in the paddock, only about 8500kj ends up on a persons plate. The more developed the society, the greater the wastage, little ever being returned to be recycled productively, huge amounts instead making it into landfill, decomposing to produce CO2 and methane. Lamenting over whether there will be sufficient nutrients to support increased growth due to CO2 is misplaced whilst such wastage is allowed to continue. The IPCC states that globally averaged mean water vapour, evaporation and precipitation are projected to increase, though there may be some shift in rainfall patterns. For Australia, in the areas where the rainfall is projected to decrease, the IPCC project a decrease in evaporation of the same magnitude if their Fig.10.12 is any indication. As for the wild fires, the argument is not even relevant, a red herring if ever there was one. Wild fires only present a problem when humans choose to settle in the areas prone to fire and build inappropriate infrastructure that is unable to be defended. Fires are a natural part of most landscapes, and where mankind is upsetting the natural cycle is not by allowing fires to burn, but by putting out the fires that would burn more frequently in less extreme conditions keeping fuel loads lower. This interference means that when a wild fire does start that is unable to be controlled, the higher fuel loads, and the fact that the conditions are generally more extreme, the results are even more devastating. -
Bern at 11:40 AM on 1 July 2010CO2 is Good for Plants: Another Red Herring in the Climate Change Debate
Hmm, that's a good point, villabolo. It's like saying oxygen is "food for humans", which anyone can see is false. Thanks for pointing that out. -
ProfMandia at 11:34 AM on 1 July 2010Perth forum on climate change: all the gory details
barry, You are correct! I was oversimplifying by looking just at the peaks over time and not the rate of change to get to those peaks. It does appear that CO2 increased fairly rapidly (on natural scales) in the 5,000 years after deglaciation. If we use the current 2 ppm rate then we are increasing CO2 about 80 times faster than nature. Sorry for the mistake. -
villabolo at 11:00 AM on 1 July 2010CO2 is Good for Plants: Another Red Herring in the Climate Change Debate
A slightly off topic point. Lord Monckton is, as far as I know, the originator of the "Carbon Dioxide is FOOD for plants" meme. For a while I thought that he was being ignorant in mixing up the sense of food and air. After all CO2 was obviously "air" for plants. "Food" would be either fertilizer for your roses or decomposing plants and animals on the Forest floor. Then I got to know the man better and noticed what a subtle manipulator he is. I realized, in a flash, the psychological brilliance of calling CO2 "food" for plants. If CO2 where to be correctly identified as "air" for plants then no one would care. The reason being that we take air for granted in spite of our inability to do without it. "Food", on the other hand, is constantly on our minds. It is a clever Propaganda sleight of hand. If John Q. Public should mention this "food" meme, we should respond to before we even get into any mother explanations. Since it is easy to explain the difference between air and food, our gently correcting Mr. John Q. Public should create the first subtle hints of doubt in his mind. Yes, I know, it's not logically relevant but if we are to communicate with people better then we have to know the difference between the psychological and the logical. -
Tom Dayton at 10:55 AM on 1 July 2010CO2 is Good for Plants: Another Red Herring in the Climate Change Debate
I posted links to a few references in my comments on the CO2 Is Not a Pollutant thread. -
carrot eater at 10:35 AM on 1 July 2010CO2 is Good for Plants: Another Red Herring in the Climate Change Debate
A strength of this website is that it gives several relevant links to the academic literature. While I understand that the point being made here is a simple logical one, moreso than a discussion of the underlying science, I suggest providing some citations here, as well. -
John H at 10:29 AM on 1 July 2010CO2 is Good for Plants: Another Red Herring in the Climate Change Debate
"That principle is that plants 'breathe in' CO2 during the day, but breathe oxygen at night: they are net consumers of CO2 ONLY while they are growing. Once they stop growing, they no longer remove CO2 for us." They only consume a small amount of oxygen. Not to mention it's not night all over the globe at the same time, so it's not like every plant on the face of the earth is consuming massive amounts of oxygen all at the same time. So your point is? -
MattJ at 10:02 AM on 1 July 2010CO2 is Good for Plants: Another Red Herring in the Climate Change Debate
Well, yes, some of us are really tired of hearing that nonsensical line, "CO2 is good for plants". After all, water is good for them too, but too much water still kills them. Even when it doesn't kill them, it can still cause poor development of the plant's root system. Both water and CO2 have to be made available to the plant at the right time and in the right quantities; going outside of either one can be very damaging. THAT is the real principle ignored by the "CO2 is good for plants" crowd. Surely pointing out this real principle is more effective than using language like 'proferred'! Mariana seems to have forgotten both the depth and the character of anti-intellectualism among the very people she is trying to persuade: use of fancy language like 'proferred' is likely to shut their ears before they have given her a fair hearing. Actually, come to think of it, there is another principle Mariana is ignoring: taking it into account could enable her to remove much of her post and write something more compact and hard-hitting instead. And this is a principle the "CO2 is good for plants" crowd has even more conspicuously ignored. That principle is that plants 'breathe in' CO2 during the day, but breathe oxygen at night: they are net consumers of CO2 ONLY while they are growing. Once they stop growing, they no longer remove CO2 for us. Unfortunately, this second principle is not common knowledge; at least in the US when I was in high school, science classes commonly mentioned that plants consume CO2, but I never heard their consumption of oxygen mentioned. Nor am I alone. Only their consumption of CO2 is common knowledge. Finally, answering KR: what she said about the fauna is also true of the flora, it is not obvious which would actually be stronger for her argument. I suspect she really meant what she wrote, since the fauna (including us) are more sensitive to variations in that 'cocktail', variations caused by AGW, possibly amplified by the plant growth assumed. -
Marcus at 09:36 AM on 1 July 2010Perth forum on climate change: all the gory details
@ Arkadiusz Semczyszak-that doesn't answer the question. If, as you claim, this detritus has been around for 10,000 years, then why didn't CO2 levels rise to above 280ppm during-or 1,000 years after-the Holocene Optimum (the peak of the current inter-glacial period)? Also, if the excess CO2 were from detritus, then we'd expect no change in the C-14/C-13/C-12 signature of the atmosphere-yet we are. -
KR at 09:33 AM on 1 July 2010CO2 is Good for Plants: Another Red Herring in the Climate Change Debate
Wouldn't that be "...the planet's flora requires..." instead of "...the planet's fauna requires..."?Response: Indeed, I hope Mariana doesn't mind that I've gone ahead and corrected this error. Thanks for the tip. -
philc at 08:53 AM on 1 July 2010Astronomical cycles
re 104 scadenp: Guess you missed the point. Scafetta's model is fitting a curve to the data. Intrinsically, the model cannot be guaranteed to work outside the range of the data. The only way it might work is if the functions chosen for the fit actually happened to be functions that were actually good descriptions of the underlying processes. In Scafetta's paper this may actually be the case, since he is using functions drawn from the data and not unreasonably extrapolating that they might continue to describe the data into the future. While the exact mechanism that might cause the climate to respond to the motions of the planets/sun/moon are not known, it is quite reasonable to assume that the mechanism is unlikely to suddenly change or that the motions of the planets are going to vary unpredictably. The mention of climate models was not the point, but just to emphasize that curve fitting is a very iffy way to make predictions. -
Ned at 08:44 AM on 1 July 2010Temp record is unreliable
BP writes: But you still don't get is. Adjustment algorithm applied by GHCN v2 is not the same for the US as for the rest of the world. And this fact is not documented. How can I say this politely? You seem not to have read even the most introductory literature about the GHCN data. You might want to start with: Peterson, T. and R. Vose. 1997. An Overview of the Global Historical Climatology Network Temperature Database. Bulletin of the American Meteorological Society, 78(12): 2837-2849. Section 6 describes the adjustment process and points out explicitly that one adjustment process is used for data from the USHCN network, and a different process for the rest of the world. It is frankly stunning that you would not have read even the single most basic paper about the GHCN data set before leaping to the conclusion that the data have been "tampered with". It's especially ironic that you are apparently under the impression that you've discovered something new and that I don't understand it. So. Yes, there is a difference between the US and the rest of the world. But as I said above, that's only the first step. You are still better off using a gridded analysis rather than naively assuming that the expected value of the adjustment is stationary across the whole rest of the world. -
kdkd at 08:15 AM on 1 July 2010Astronomical cycles
Ken #113 Again I refer you to my response #108. Your continued ignoring of this inconvenient truth (that the measurements are insufficiently precise over very short time periods rendering your argument invalid) appears to demonstrate that you're mainly interested in hiding under a cloud of technical sounding rhetoric. Anyway, doesn't this discussion live in the sea level rise thread? -
Doug Bostrom at 08:09 AM on 1 July 2010Perth forum on climate change: all the gory details
Further to tobyjoyce's thoughts, despite all the ineffectual #9 birdshot volleyed in the direction of Earth climate theory and models, doubters would do better by concentrating on the effect of clouds on sensitivity. Why there's so much attention paid to mirage targets is an enduring mystery. -
tobyjoyce at 08:01 AM on 1 July 2010Perth forum on climate change: all the gory details
@actually thoughfull, Is climate sensitivity really the skeptics-deniers strongest argument? Evidence can be presented that it is ~3C or so. There is no strong evidence that it departs for that figure in a significant way - the Lindzen&Choi paper and Dr Roy Spencers efforts have not bee met with any acceptance in the scientific community. The burden of proof is on the positive claim, and the evidence has been provided. Reasonable doubt is the task of the rejectionists, but they have failed to meet that standard. -
Peter Hogarth at 07:58 AM on 1 July 2010Astronomical cycles
Ken Lambert at 00:37 AM on 1 July, 2010 I've downloaded the latest Colorado data. The original full series for all satellites are netcdf format from other sources, but I'll have to wait until I get to work to download that and double check. If you look at the Colorado website there's a section on updates. There was a problem (as I indicated) with Jason 1. I suspect that either Jason2 data has been spliced or has been merged from 2008 in the data you have, making your trends a little dubious, The 2.61 mm/yr trend I indicated is from "pure" (corrected) Jason 1 data. I will check as my last full download was a couple of months back. Anyway, I would gently suggest that the data variability (I have also seen the raw data!) means that we have to average all of the data available to allow our trend to be as robust as possible (statistically), rather than try to make mini-trends of sub-sections and draw conclusions, the +/-0.4mm/year error is only valid over the entire time series. If I include all satellite data our confidence in the result should increase. Try putting 2 sigma error bars on your data? I don't think "flattening" SLR or "conflicting data" is supportable here. -
Doug Bostrom at 07:51 AM on 1 July 2010Temp record is unreliable
BP, not to barge in again but perhaps you could simply ask the folks responsible for an explanation of what you think you see? They seem to invite this: For all climate questions, please contact the National Climatic Data Center's Climate Services Division: Climate Services and Monitoring Division NOAA/National Climatic Data Center 151 Patton Avenue Asheville, NC 28801-5001 fax: +1-828-271-4876 phone: +1-828-271-4800 e-mail: ncdc.info@noaa.gov To request climate data, please e-mail: ncdc.orders@noaa.gov -
Tom Dayton at 07:48 AM on 1 July 2010Temp record is unreliable
BP, an example is an adjustment for the time of day at which a temperature was measured at a station. At least in the U.S., temperatures at many stations originally were measured at the same time every morning. Then many of the stations (all?) changed to measure at the same time every afternoon. Those stations' temperatures from before the time-of-measurement change had to be adjusted to eliminate the difference that was due to the time-of-day change. -
Berényi Péter at 07:21 AM on 1 July 2010Temp record is unreliable
#84 Tom Dayton at 06:58 AM on 1 July, 2010 if you take any two subsets of the stations, you will see the adjustments differ You must be kidding. It is not just any two subsets. What kind of algorithm can have this particular effect? I mean US data were adjusted upward by 0.27°C during the last 35 years while there was no adjustment at all for the rest of the world. Also, between 1870 and 1920 US trend was adjusted downward by 0.4°C while the rest of the world was adjusted slightly upwards. One should be able to tell what makes US weather stations so special. Anyway, I am just checking if there's any other pair of complementer subsets with such a weird behavior. -
werafa at 07:09 AM on 1 July 2010What is Global Warming and the Greenhouse Effect?
Re the car radiator theory What about an evaporative air conditioner? This adds water vapour to the air, and in the process, it cools you more than a fan does. why? Because the process of converting liquid to gas locks up a lot of heat energy (latent heat). This latent heat is trapped in the molecular structure of the water vapour, and is re-released when the vapour condenses (another reason why it is warmer on cloudy nights). So the radiator in a car would work much more efficiently on a foggy morning, and water vapour is not the only gas in the amosphere that can absorb heat. The alternative is that the heat is simply radiated in all directions, with a fair amount being lost in space. So yes, the car radiator analogy does have merit even though it is an artificially amplified system (same as enhanced global warming actually) -
Tom Dayton at 06:58 AM on 1 July 2010Temp record is unreliable
In other words, BP, if you take any two subsets of the stations, you will see the adjustments differ. Even though the same adjustment algorithm was applied. -
Tom Dayton at 06:39 AM on 1 July 2010Temp record is unreliable
BP, the adjustments are not the same anywhere, because the adjustments are peculiar to the individual circumstances of those cases. The adjustment algorithm is not just a formula, because it needs to accomodate events such as a station getting run over by a bulldozer and being repaired. -
RSVP at 06:34 AM on 1 July 2010What is Global Warming and the Greenhouse Effect?
Chris G I think you only need the antenna to be half the actual wavelength... KR Wait a minute. You wont need to heat your house. It will already be globally warmed, and if not, maybe this will bring you closer together! Its a win, win situation. -
Berényi Péter at 06:24 AM on 1 July 2010Temp record is unreliable
#80 Ned at 22:29 PM on 30 June, 2010 as with everything in statistics you need to understand your assumptions Exactly. But you still don't get is. Adjustment algorithm applied by GHCN v2 is not the same for the US as for the rest of the world. And this fact is not documented.Overall effect of adjustment on trend may be small (0.1 K/century), but the adjustment procedure itself can't be correct.
-
Chris G at 06:14 AM on 1 July 2010What is Global Warming and the Greenhouse Effect?
Nvd, I'm forgetting velocity factor, and possibly other stuff. -
KR at 06:12 AM on 1 July 2010What is Global Warming and the Greenhouse Effect?
At that point, RSVP, I will be using my own hot air on this topic to heat my house, much to the displeasure of my lovely spouse. -
Doug Bostrom at 06:12 AM on 1 July 2010What is Global Warming and the Greenhouse Effect?
Chris G, you're right, I took the 2200mHz number off the top of my head and remembered incorrectly. Middle-age fog=Bad mismatch! -
KR at 06:09 AM on 1 July 2010Hockey stick is broken
To clarify my previous statement, marty: An invalid measurement (paper, data, whatever) is a lack of evidence for something. It really doesn't say anything about other evidence supporting a particular conclusion, just that the particular measurement has issues. A valid and contradictory measurement, on the other hand, is evidence against something. That's the category that retrograde planetary transits fall into. I really haven't seen any valid contradictory evidence regarding the conclusion of human driven global warming - nothing that held up as valid under examination. -
Chris G at 06:07 AM on 1 July 2010What is Global Warming and the Greenhouse Effect?
Hey Doug, Testing my long unused physics: If a typical microwave operates at 2.45GHz, wouldn't that correspond to a wavelength of about 12.2 cm ~= 4.75 inches. So, shouldn't the optimal bit of wire be that long? -
KR at 05:57 AM on 1 July 2010What is Global Warming and the Greenhouse Effect?
johnd - we discussed relative amounts of energy exchange at quite some length over on CO2 is not the only driver of climate. As you might (or might not?) recall, radiative exchange is about 4x that of conductive/evaporative energy levels - 396 W/m^2 versus (24 convective + 78 latent heat)=102 W/m^2. Please re-read that thread if you still have issues with this; I really don't want to debate it again. The *measurements* show it. As to the "confusion about how powerful CO2", there's really NO confusion whatsoever as to the effect of CO2, or whether that effect exists, also here. There are certainly questions about the level of positive/negative feedbacks with water vapor and the like, but CO2 forcings with changing concentration are really the easiest to account for - and quite significant. -
johnd at 05:36 AM on 1 July 2010What is Global Warming and the Greenhouse Effect?
RSVP at 00:24 AM, your point 2 is exactly correct. The work done by each molecule is what is important, not the presence of the molecule itself. The crucial difference is that the H2O molecule changes state twice each time it cycles, whereas the CO2 molecule does not. The change of state requires the absorption of heat energy and the dissipation making the H20 molecule very suitable for transporting heat energy. Thus the less time each H2O molecule resides in the atmosphere the greater the amount of heat energy transferred to the atmosphere from the surface. Under the conditions that the greenhouse effect provides, CO2 is not capable of performing this role. Given the total amount of water vapour in the atmosphere remains at about 2%, 20,000ppm, if the average residence time of a H2O molecule decreases then the amount of heat transferred from the surface, and the amount of precipitation would also increase. The clouds that form as part of the cycle are also always present varying between 64% and 69% coverage globally. On the other hand what actual work does a CO2 molecule do in the atmosphere? We do not see CO2 forming clouds of dry ice do we?It does not change state under the conditions that exist in the atmosphere. It's cycle requires it to remain close enough to the earths surface to be sequestered by plants or absorbed by the ocean, broken down into it's components and then reformed before it can be released to complete another cycle. Those CO2 molecules that reside in the atmosphere are obviously lost, like street urchins who are unaware that there is a purpose for their existence, and a real role for them to play if they can just get back into the system again. It's seems that there is some confusion about how powerful CO2 is as a greenhouse gas. There is a need to separate the direct effect, and the nett effect as a forcing agent acting on water vapour. Any warming due to the greenhouse effect is thus directly attributable to H2O, and only indirectly to CO2. The direct effect of CO2 itself is small and requires amplification. -
Doug Bostrom at 05:22 AM on 1 July 2010Return to the Himalayas
Hi HR, sorry I did not notice your comment until now. Funny thing is, I live in a place where nearly all our "juice" comes from hydropower. Turns out we overdid it a bit and it appears we will be selectively removing a few dams because they've seriously interfered w/salmon runs, causing negative impacts on some sectors of the local economy. Choosing to remove these dams has been a delicate decision process because their utility has of course been integrated into our local systems in a way that needs unraveling without excessive harm. It's all a question of balance and poise, I believe. -
Chris G at 05:05 AM on 1 July 2010What is Global Warming and the Greenhouse Effect?
#49 "...which as I said does not emit IR. " OK, maybe it doesn't emit IR (though IR covers a lot more spectrum than what we normally consider); I'm pretty sure the gases other than what we call GHGs emit energy at some wavelengths. Also, relatively excited molecules will transfer energy to their neighbors. This in true for all molecules; you must know that. The end result is that energy is still dissipated to the surroundings. Once the energy from the fire or engine is dissipated to its immediate surroundings, it makes no difference whether that happened through radiation or convection, , if the original molecule was CO2 or N2, or if what was hot was a rock or a piece of aluminum. -
Doug Bostrom at 05:05 AM on 1 July 2010What is Global Warming and the Greenhouse Effect?
A ~5.3 inch piece of wire suspended in an otherwise empty microwave oven will do nicely for the mad scientist experiment. Wear welding goggles. -
KR at 04:51 AM on 1 July 2010What is Global Warming and the Greenhouse Effect?
RSVP - if you're talking about exhaust gases, yep, the energy starts with the CO2/H2O combustion products. I believe that by the time the exhaust has reached the end of the muffler, however, you're close to thermal equilibrium with the remaining O2 and N2. Your example, however, was an automobile radiator, which conductively heats ALL of the air mass, moving that energy out of the car via convection. And yes, yes, convective cooling in your house from a hot air register is different from radiant heat. Convection, conduction, radiation - all valid paths in some amount for heat energy, until you get to the top of the atmosphere and only radiation works. That's why the Trenberth diagrams and supporting measurements are so important - determining how much goes through each pathway. Whatever; GHG's act as effective antenna (absorb/emit) for thermal band IR. I think I have a mad scientist experiment for my next party now! I just have to get a (cheap) AM transmitter I don't care about... -
RSVP at 04:44 AM on 1 July 2010What is Global Warming and the Greenhouse Effect?
By the way, I actually like the antenna analogy. Try transmitting 1000 M Watts of AM radio through a safety pin and see what happens! -
RSVP at 04:38 AM on 1 July 2010What is Global Warming and the Greenhouse Effect?
Chris G Combustion produces two IR radiative gases: water vapor and CO2. These two gases come out of a fire with a fairly high temperature. I have said nothing above about N2 or O2 getting hot. As far as heat radiating from the Earth, you cant have it both ways. Either N2 and O2 allow IR though or they dont. If they are transparent to IR, then you have to admit that convective cooling through a radiators (or home heating for that matter) is directly elevating temperature in a way that differs from fire and sun heated bolders. -
Chris G at 04:36 AM on 1 July 2010What is Global Warming and the Greenhouse Effect?
RSVP #48, Mmm, no, in a hydroelectric dam the energy out is the difference between the gravitational potential of the water going in versus the gravitational potential of the water going out. How the water got uphill from the dam can be any number of stories. -
KR at 04:34 AM on 1 July 2010Hockey stick is broken
A small inconsistency can be an issue with a larger theory, marty - if the measurement is accurate/repeatable. Retrograde planetary transits certainly fit in that category. Unfortunately, many 'skeptic' arguments involve disagreements on interpretation, completely incorrect data, arguments about data normalization and calibration, etc. - and each (mis)point is used to argue that the Earth isn't warming, or we aren't the cause, or it won't hurt us anyway. An error in measurement (if it exists) is of quite different importance than a solid measurement that contradicts the theoretic predictions. I haven't seen any of those, really; the only recent issues I've seen that required consideration were ocean heating measurements and the tropospheric hot spot - and after the discussions I have to agree that these do NOT invalidate the conclusions of human driven global warming. You might find the list John has put together of the standard arguments quite interesting. -
actually thoughtful at 04:24 AM on 1 July 2010Perth forum on climate change: all the gory details
I think the best skeptical argument is the interplay of positive and negative feedbacks. As I understand it, CO2 itself is good for .75-1.0C of temperature increase per doubling of CO2. The consensus "all-in" temperature increase is 3C/doubling. However, in my understanding of the science, feedbacks seem to be the most complicated, dynamic and chaotic of all of the climate related issues. Some feedbacks are both positive and negative (cloud cover). A recent discussion on RealClimate.org highlighted an aspect of the uncertainty: http://www.realclimate.org/index.php/archives/2010/02/good-news-for-the-earths-climate-system/ I strongly suspect the 3C figure will turn out to be robust, but I think it is the strongest argument the skeptics have, as the data is not all in, and reasonable doubt can be cast upon ice core records, tree ring data, etc., etc. -
Chris G at 04:20 AM on 1 July 2010What is Global Warming and the Greenhouse Effect?
RSVP, KR's comment with regard to the antenna aspect of GHGs took me a second, but then I got the metaphor that just as antennas are sensitive to certain wavelengths, dependent on the length of the wire, and much less to others, gases absorb and emit at specific wavelengths. I'll connect the dots regarding your engine example. Suppose that instead burning fuel in an engine, you simply burned the same amount of fuel directly. Is there any difference in the amount of energy released? None whatsoever. Does the engine's cooling system transport the energy to some higher altitude where it can be radiated off the earth with less impedance? No. Hence, my simplification to just fire. The heat from naturally occurring sources does not simply accumulate; so, it would take a bit of magic to make the heat from manufactured ones to do the same. -
KR at 04:17 AM on 1 July 2010What is Global Warming and the Greenhouse Effect?
Sorry! John, could you wipe the two duplicates there? I hadn't realized I was running onto the next page! (Doh!)Moderator Response: No problem. Operational detail: If you happen to post just before the comments thread is going to "roll" past the first page of comments, your view will remain on the page you started from but your comment will actually appear on the next page. -
KR at 04:15 AM on 1 July 2010What is Global Warming and the Greenhouse Effect?
It's pretty straightforward, RSVP. Gasses aren't perfect blackbodies (nothing really is), and in fact N2 and O2 have pretty lousy absorptivity and hence emissivity (Kirchoff's law) at the IR wavelengths a blackbody would radiate at our surface temperature. They heat and cool very slowly with IR, much as a polished silver surface is a poor absorber/emitter of daylight. CO2 and water vapor, on the other hand, are handy at absorbing/emitting IR in the 4-15 micron thermal IR bands. They both absorb (raising electron states, heating up the molecule both electronically and vibrationally) and emit (dropping electron levels which are pumped by vibrational inputs, losing energy) quite well. When an air mass is losing IR to the surroundings (net output), the CO2 and H2O molecules will be on the whole cooler than the air mass due to radiation, repeated brought back to the air mass temperature through collisional interactions. When an air mass is heated by IR, the CO2 and H2O are hotter than average than the the rest of the air mass, with collisions warming the entire 100% of air molecules. At equilibrium (same coming in as going out) the GHG's will be at the same average temperature as the rest of the air mass. Granted, pure CO2 would heat/cool faster, with a much higher exchange rate with it's surroundings. But the fractional percentage of CO2 and H2O in air provide an energy pathway via IR exchange that would be nearly non-existent otherwise for the air mass. CO2 and H2O (and methane, ozone, etc.) are thereby preferential infra-red interaction molecules (IR antenna), heating or cooling the entire air mass through the net IR exchange - much as the water in your food acts as a receiving antenna in your microwave oven, heating the rest of the food through microwave absorption. -
Doug Bostrom at 04:00 AM on 1 July 2010What is Global Warming and the Greenhouse Effect?
Clarifying RSVP's remark, the Earth is not "getting hotter all the time because of C02", it's going to become warmer until radiative balance against additional retained heat is achieved at which point temperature will stop trending upward due to the particular system of forcings influenced by C02 and will then dither and possibly trend upwards or downwards due to other causes, as it always has. Not only may we count the beans we have, we may propose removing or adding beans and then calculate how many beans will be available if or when such quantities of beans are actually manipulated. Different hands may reach into the pot and either add or remove beans. The hands we're speaking of here wear gloves marked "anthropogenic C02." Always watch the hands, don't look at the brightly colored scarves being waved about. -
RSVP at 03:52 AM on 1 July 2010What is Global Warming and the Greenhouse Effect?
Woops Very sorry about that Chris G. It was KR who explains that CO2 acts as an antenna for other gases. -
RSVP at 03:48 AM on 1 July 2010What is Global Warming and the Greenhouse Effect?
To Chris G (again) "Regarding #39, Nothing in nature burns? Nothing in nature gets hot? If greater than zero things get hot in nature, what would be the accumulated heat over, say, 4.5 billion years?" Please do not misquote me. I did not say that. I was referring to my cars radiator. An aluminum heatsink with thousands of orifices where air passes through cooling water heated by my engines water jacket. This is Man's invention. So are nuclear power plants, and all other forms of boiler burners etc. These are in addition to the heat that already exists due to the sun warming us as it should. This "small" amount of heat is heating the air which as I said does not emit IR. Now you are telling me that the GHG are acting as an antenna to get rid of this radiation. I am listening. I would like to hear more about this.
Prev 2315 2316 2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329 2330 Next