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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.
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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. -
RSVP at 03:41 AM on 1 July 2010What is Global Warming and the Greenhouse Effect?
<> Clarifying: Perpetual motion does not exist. Hydroelectric delivers energy. It is not a perpetual motion machine. The guzins being the Sun. The guzouts being Earth cooling. Meanwhile man is tapping into this "machine". The sun continues to shine as always (guzins doesnt change). The guzout is constant (or per AGW now working less efficiently, but this has nothing to do with my clarification). Somehow in this equation, energy is comimg from somewhere, but according to AGW its getting hotter all the time because of CO2. We have left the realm of electromagnetics, quantum physics and are now only talking about bean counting. -
marty at 03:05 AM on 1 July 2010Hockey stick is broken
Ok well for the sake of trying the debate I've posted a question about this on the comments box accompanying the article with a link to the article above. unfortunately I couldn't raise KR's claim about the small difference the inclusion/exclusion of tree ring data makes since I hadn't read it at that point. I would like to see what anyone following the link will have to say. I would disagree about the skeptic tactic bit though since it is a 'tactic' used by science in general. A tiny seemingly peripheral detail like the weird backwards looping about of a planet bought the whole glorious earth-centric universe tumbling down. Cheers. -
Doug Bostrom at 03:01 AM on 1 July 2010Sea level rise is exaggerated
I don't find your remarks persuasive, Daniel. Your entire thesis depends on deriving -more- interpretive detail from a data series you yourself claim has insufficient power to describe -less- detail. That's nonsensical. By the way, Donnelly does not own the term "conservative." It's commonly used in science the same way we might use "circumspection" or other words suggested suitable humility in the face of ignorance. -
KR at 02:56 AM on 1 July 2010What is Global Warming and the Greenhouse Effect?
Chris G - if you're interested, I found a little bit I wrote on lapse rate, latent heat, thunderstorms, etc, over on "CO2 is not the only driver of climate". This was in the context of a conversation on the relative importance of ground driven convection and latent heat as energy transfer mechanisms, with a background discussion of the (much larger) radiative energy flows. -
Philippe Chantreau at 02:53 AM on 1 July 2010Ocean acidification
CO2 bubbling? A piece of ocean acting like a soda pop? Sorry but that looks like total nonsense at first glance. -
Philippe Chantreau at 02:46 AM on 1 July 2010What is Global Warming and the Greenhouse Effect?
"intensely forced convection that is not found anywhere in nature." What a convoluted way to make a false assertion for the sake of argument. Check out these pictures, the convection in them dwarfs any engine cooling system. They routinely contain vertical wind shear in excess of 60 mph. http://www.mesoscale.ws/pictures/structure/ -
KR at 02:45 AM on 1 July 2010What is Global Warming and the Greenhouse Effect?
Absolutely right, Chris - the distance varies with the number of GHG molecules per unit volume. I was typing quickly (carelessly) there about the lower atmosphere; mean free path length increases as pressure drops. -
barry1487 at 02:43 AM on 1 July 2010Perth forum on climate change: all the gory details
Scott Mandia, thanks for the reply. I was under the impression that glaciation took the longer time, and that deglaciation, accompanied by rising CO2 levels, took ~5000 years in late Quaternary ice age cycles*. I'm sure the skeptics I face would soon point this out and the main point would be derailed. * (Again, please correct any misapprehension on my part) -
KR at 02:40 AM on 1 July 2010Hockey stick is broken
marty - an excellent question. Kudos to you for checking additional data sources; many people don't bother. As Tom pointed out, there are a number of different temperature measurements (proxies) listed at the top of the page. I believe the Mann 'hockey stick' is composed of data from ~100 different temperature estimates, including some tree ring data. Mann felt (with some reason) that the later part of the tree ring data set was distorted, possibly due to other influences (drought) on tree growth for those proxies. It doesn't really matter, though, as including/excluding the later period tree ring data doesn't really change the graph by more than a couple percent either way. This is a popular 'skeptic' tactic, marty, which you might see elsewhere - picking a tiny piece of evidence, pointing out issues (correct or not) with it, and using that to claim that a conclusion based on many, independent lines of evidence is therefore invalidated by that tiny piece. -
Chris G at 02:33 AM on 1 July 2010What is Global Warming and the Greenhouse Effect?
#37, Umm, no, I don't see a connection between what I said and what you said. 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? #40, Gases absorb and emit at the same wavelengths, specific to each gas. If 97% of the air does not emit IR, it doesn't absorb it either; it passes through unaffected. KR, thanks for the detail. I think got the gist of correcting myself at #34. I'm confident you know this, but I'd think the distance traveled would be dependent on the density of the gas. The density of air diminishes rapidly with altitude; so, I suspect it is a mistake to use a fixed value for distance traveled. -
Tom Dayton at 02:29 AM on 1 July 2010Hockey stick is broken
Marty, read the post at the top of this page. See all the graphs of temperature data from sources that do not include bristlecone pines? -
Peter Hogarth at 02:25 AM on 1 July 2010Sea level rise is exaggerated
daniel at 10:49 AM on 30 June, 2010 Much of this debate is focusing heavily on one Donnelly paper based on data from one area (Southern New England). Let me take a different tack. If we accept that the temporal sampling in Donnelly 2004 on historical sea level is sparse, we have two options. 1) We look for more data to fill in the gaps from other sources, and build up a higher resolution composite. Though there are difficulties with different rates of rise in different regions this process is ongoing and 6 years is a long time in climate research. From what I have read and am aware of in a professional capacity the evidence suggests relatively small changes in sea level over this period consistent with Donnelly (allowing for occasional dramatic localized crustal movements). 2) We also look at the physical effects which cause sea level rise and see if these have changed over the period in question. This might be viewed as “modeling”. Any dramatic sea level variability between or over the temporal range of uncertainty of the samples (as you suggest could hypothetically be present) would be driven by dramatic variability in temperature, land ice volume or hydrological cycle, or some combination. The evidence on past variability in temperature is far denser temporally and spatially and better researched, and is consistent with the published estimates of past changes in sea level (for example see Grinsted on Medieval Warm period). The ice core data which can give not only regional (North and South) temperature proxies but estimates of deposition/loss rates is consistent with this also. Then we must apply this same logic to what is happening now, and look at recent research in other areas of climate related science. Temperature is rising, global ice mass is diminishing and sea levels are rising with both thermal and ice melt contributions. For some more recent overviews and a few more clues on extra data see Church 2008, and Milne 2009 as well as Grinsted linked previously. -
KR at 02:22 AM on 1 July 2010What is Global Warming and the Greenhouse Effect?
Very true, RSVP - and that 3% is the 'antenna' that the energy of the entire mass of air can radiate IR from. Or receive upon, for that matter. And as the CO2 and water vapor lose/gain energy from IR, thermal collisions with the rest of the air mass spread those effects throughout, lowering or raising the temperature of the entire air mass. -
marty at 02:20 AM on 1 July 2010Hockey stick is broken
I just read an article saying that it was responsible for the hockey stick appearence and wondered if it was true that it makes temperature records have a hockey stick shape. Obviously if there are hockey stick shaped graphs that don't include the tree ring records of bristlecone pine then the article is clearly wrong. The article is on a site called spiked and I was rather hoping that someone knowledgeable about this issue might like to clarify things either here or in a posting to the letters page on spiked. http://www.spiked-online.com/index.php/debates/copenhagen_article/9056/ Since I haven't made up my mind about the science I obvioously flit between sites like spiked and this one. I'll have a look at the NOAA site and if it's not too technical I'll see if I can figure it out myself seeing as no one here can just give me a straight answer to what seemed to me a straight question. cheers -
KR at 02:17 AM on 1 July 2010What is Global Warming and the Greenhouse Effect?
Chris G - latent heat is estimated at ~76-78 W/m^2 (can't remember exact number off the top of my head) from liquid to vapor form; evaporated from surface water and ground moisture. This gets deposited primarily at the condensation point in the lapse rate where clouds form - no energy is deposited by condensation until the bottom of the cloud, when the temperature has dropped enough. Thunderstorms and major convective events (hurricanes) can draw water vapor high into the troposphere and even in extreme cases the lower stratosphere, but generally the energy movement is to the middle troposphere. I wrote something quite wordy about thunderstorms, lapse rates, and the like, in a previous topic, and now I can't find it! Oh well... Given that the IR pathlength is on the order of 10's of meters before absorption/emission events, this certainly moves the heat into the atmosphere, warming it. IR radiation to space occurs when CO2 density and total water vapor (along with total pressure) drops low enough to permit it, in the stratosphere, hence the GW phenomena of a warmer troposphere and colder stratosphere. -
Alexandre at 02:16 AM on 1 July 2010What is Global Warming and the Greenhouse Effect?
Very nice text. The radio analogy is definetely one I will use when explaining the frequency spectrum to other lay people. -
RSVP at 02:09 AM on 1 July 2010What is Global Warming and the Greenhouse Effect?
KR <> As was sited way above, water vapor and CO2 only make up about 3% of the atmosphere. AGW rests on the asumption that the other 97% does not emit IR very well. That is what our engines are warming. -
RSVP at 02:03 AM on 1 July 2010What is Global Warming and the Greenhouse Effect?
Chris G The engine cools through intensely forced convection that is not found anywhere in nature. -
daniel at 02:03 AM on 1 July 2010Sea level rise is exaggerated
Further quotes from #33 "if I get you right and correct me if I'm misunderstanding you, you're suggesting that it's equally reasonable to pick and draw a series of lines perhaps pointing up and perhaps pointing down between any chronologically linear pair of samples." Well almost, what I'm really saying is that the paper hasn't got a hope of determining the short term sea level trends during 1300-1850 AD. This ties in with what you say next: "That's not as conservative as doing what Donnelly did." You like to regurgitate that word but I wonder if you know why Donnely et.al. used it? It's because they are trying to claim that the centres of their 95% confidence boxes are of a higher likelihood of being where the true paleo record lies. I cautiously agree with them on that, but I can't see how it legitimises their final comparison. If the centres of the boxes were the true paleo sea levels then in an attempt to obtain short term trends from the data (which is tje only valid comparison to make when trying to detect unusual recent uptrends in the last 150 years) you could in principle draw lines between each pair or in other words connect the dots. But then you would have to explain the jump back in time between samples 10 and 9 or explain why the rapid rise in sea level between samples 7 and 8 is not as, or even more alarming, then the recent rise over 150 years. No I won't let them have it both ways. If thier long term trend line doesn't need to cut right through the centre of the boxes then neither do my short term trends. You continue: "As well, doing such a series of arbitrary choices leaves the issue that the entire series must begin somewhere within the region circumscribed by the sample 4 and 11 confidence boxes, meaning that the overall conclusion of the series of choices made to connect individual samples ends up being nearly the same, confined by the beginning and ending samples." Sigh. When will you understand that the important point here is that a lack of certainty in short term trends invalidates any claim that recent rises are alarming. "Meanwhile, it appears that the slope described by the direct recent tidal measurements is inevitably going to be steeper than the sum linear product of whatever combination of ups and downs you might choose to impose on the paleo series..." Same as above "sum linear product" is irrelevant, short term uptrends of similar rate and range are. They cannot be detected by a study of this type. "...and as well covers a disproportionate vertical range compared compared to the paleo series. This suggests to me that attempting to create and insert arbitrary additional information into the series is pointless." No the paleo data covers something like 60-70cm and the recent data covers 30-40cm. Plenty of slack for a similar uptrend and a plateau. " The suite of dating refinements employed by Donnelly I refer to are an example our ignorance, as I mentioned before." You make it sound complicated but as I've outlined before, people who are educated in distant fields to climate science can easily understand a climate science paper. The principle of superposition is simply applying the logic of higher stratum are younger than lower stratum. Using known historical markers from the introduction of different plant species as added refining tools for dating is not complicated. Just becausr you don't understand it doug doesn't mean that I don't. -
KR at 02:02 AM on 1 July 2010What is Global Warming and the Greenhouse Effect?
RSVP - Duh, when your radiator heats the air it cools by conduction, convection, and (via heating ALL of the air in that space) heating CO2 and water vapor, which can indeed emit their energy as IR. Come on, RSVP - I've read your posts, you know this stuff! And you know (or should by now) that total waste heat from industrial (and automotive) processes represents 1/10,000 the energy of the CO2 driven radiative imbalance. It has no significant impact on global warming. -
RSVP at 01:59 AM on 1 July 2010What is Global Warming and the Greenhouse Effect?
Chris G at 00:51 AM on 1 July, 2010 #32 That is a good question, but it sounds like you are implying that hydroelectric power is trapping heat, since you cant get something for nothing. If the net effect is zero, where is the energy from a dam coming from? Are you now saying that dams are causing global warming as well? -
Chris G at 01:57 AM on 1 July 2010What is Global Warming and the Greenhouse Effect?
Regarding #33, OK, I wondered if you were talking about condensation of water vapor, but I still think you are not considering the wavelengths outside of what the human eye can detect. 'White' just means that all 3 flavors of our cones are highly stimulated, but each flavor of cone is optimally responsive on a fairly narrow band. The human eye is actually pretty limited; we can't even tell the difference between a red-green brown and a blue-orange brown. But, I digress. Clouds don't treat all wavelengths the same; as evidenced by people getting sunburned by UV on a cool and cloudy day. How does the air warmed by your engine cool? Same as warm air has always cooled since the earth was formed; but ultimately, energy only leaves the earth, atmosphere included, through radiative processes. -
KR at 01:53 AM on 1 July 2010Sea level rise is exaggerated
daniel - while the tone on this thread has become quite heated, you have made some extremely strong statements (utter joke) regarding the Donnelly paper. Looking at your initial comments, are you indeed saying that the current rise in sea levels could drop in between the samples Donnelley collected? And that therefore their data is not strong enough? Keep in mind that while there _may_ be space between samples for a steep rise, it would have to be accompanied by an equally steep decline or halting trend to match later samples. And that the samples are independently dated except for elimination of carbon date repeats by physical position ordering - an excellent technique for disambiguation, I would add. Between the multiple species examined, carbon dating, choice of uncompacted site, etc., this is an excellent paper. And hence, it shouldn't be a surprise that some people have reacted strongly to your harsh dismissal of it. As to sample 11 (representing ~8% of the data) - you may have a point there, it looks like they left the younger (eliminated) date box for #11 on the chart. But their fitting appears to use the information from Table 1, and while this looks to be an editing issue, that doesn't seem IMO to affect their calculations or their conclusions. They certainly seem to have used the #11 older date for the curve fitting. And as to how such an error might occur? While editors appear to be inhuman in nature (grrr) they are actually fallible in reality. I'd suggest dropping a note to Donnelly et al and asking whether this is the correct chart. It might be interesting to ask if these samples could be used as date tags, and examine intermediate samples (in some number) to see if there were fossil variances indicating different levels of sea rise (short term variations) - but as it stands, with the data they extracted, the linear mapping with a curve at the beginning of the industrial era is perfectly justified by the data used to generate the trend lines.
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