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SNRatio at 21:39 PM on 21 November 2009High CO2 in the past, Part 2
#21 DrMike, you may want to read up on the basic physics here, as the problem you perceive completely disappears upon analysis. Chris Colose has an excellent introduction: http://chriscolose.wordpress.com/2009/10/08/re-visiting-cff/ Maybe you can come back here after having penetrated the subject a bit. The paleoclimatic record seems to confirm that the basic physics concepts are, basically, correct. If you can show that the theory does not fit with the data, that would be very interesting - but you have to apply the theory correctly to do that. Just a hint: CO2 radiative forcing goes with the logarithm of the concentration ratios, so ln(5600/280)=ln(20)=3. With no positive feedback, the first order approximation to the temperature rise from 56 vs 280 ppm CO2 is 3*5.35*0.27=4.3 deg C. Feedbacks will in most circumstances make the effects larger, but that is counterbalanced by a far weaker sun than today. -
Riccardo at 19:30 PM on 21 November 2009The albedo effect
Henry Pool, i don't see any proof of whatever but just what you immagine would happen. It's offtpic in this post on albedo talking on attribution of global warming, but anyways, whenever you immagine a possible cause you should quantify it to confirm that you get reasonable numbers. Anyone could say to not have a swim because the ocean would warm ... -
Marcus at 18:41 PM on 21 November 2009Is Pacific Decadal Oscillation the Smoking Gun?
Here's the thing I keep coming back to-Decadal Oscillations have been going on since time out of mind, yet we're supposed to believe that *suddenly* they're generating a 60-year long warming trend. If so, what has changed in the DO's to make them do this? The oceans might store & distribute heat but, last I checked, they couldn't create that heat out of nothing. Isn't it possible that atmospheric warming is driving changes in the Decadal Oscillations, rather than the other way around? At days end, over the last 60 years, we've been seeing the fastest rise in global temperatures in more than 12,000 years-& the only thing which has changed significantly in the same period of time is the atmospheric concentration of greenhouse gases. Perhaps that's a coincidence, but Occam's Razor suggests otherwise. -
Henry Pool at 18:40 PM on 21 November 2009The albedo effect
To make it even more interesting you could do a third experiment at the CO2 concentration as it was 50 years ago, i.e. 280 ppm. But let's face it. I don't expect either the odd 280 nor the current 350 ppm's CO2 to make any difference on the heat retention inside that vessel. Maybe if you filled the vessel up to 50 or 100% CO2 would you see some influence on the heat retention. But that has been my point from the beginning: you must do your testing in the relevant concentration range. So what is my conclusion? I have clearly proven to you with my experiment no.1 that global warming is most probably caused by the increase in energy released in the atmosphere due to human activties. Think of all the warfare in the past,explosions of atomic boms in the Indian ocean, oil and gas fields burning, etc. Also, living in Africa, I would say that people living without electricity do not necessarily cause less energy to be released. To cook and to stay warm they just burn anything that they can find, and you cannot blame them. If global warming is indeed not caused by carbon dioxide you may feel a little less guilty about driving your car. But don’t open the champagne bottles just yet. The fight against global warming might in fact get more difficult. If global warming = us, we would have to reduce the total energy output per person. We have to steal energy from nature. (Wind, gravity, tides, solar etc.). Carbon emissions would not be green. Nuclear energy would not be green. Hydrogen and oxygen combustion (rocket fuel) would also not be green. In fact, in that case we will have to re-visit the whole global warming debate, for example in the case of sending rockets out to space: will the burden of all that energy released in the atmosphere by placing that satellite in orbit, result in similar savings in energy on earth? -
Marcus at 18:27 PM on 21 November 2009Is Pacific Decadal Oscillation the Smoking Gun?
The only reason the UAH data diverges from all the rest is because the UAH was relying on Diurnal (day & night) data-which resulted in a lower temperature anomaly. Other researchers have corrected for this error, & the resulting data set is now virtually identical to that of GISS, RSS & HadCRU datasets. -
DrMike at 17:45 PM on 21 November 2009High CO2 in the past, Part 2
Of all the discussions on this website, I think this one deserves the most attention. I think it is the thinnest defense for the climate guys, and the most powerful argument for the skeptics. What I mean to say is that if there were no explanation for why CO2 could be in the thousands of PPM with no concomitant substantial temperature rise, it would be game over for the climate guys. My initial inclination when I look at the plot in Figure 2 is to sarcastically say "How Convenient" it is that the radiative forcing numbers work out to be what is presented. I'll hold that jab for a moment though. The burden of proof is clearly on the climate guys on this one. I have some questions. 1. Why do glaciations initiate at both ends of the radiative forcing timeline(+4 at the end of the Paleogene, and -4 in the middle of the caroniferous timeframes)? 2. Why is there no glaciation at the minimum in the forcing timeline (middle permian)? As far as I can tell, the concept of radiative forcing is really just a mathematical fit of the correlation between T and CO2, without substantive quantitative causal evidence. There is certainly reason to believe in a qualitative causal relationship between CO2 and T, but to quantify the causal relationship based on a correlation and physical inference is a leap. -
DrMike at 17:14 PM on 21 November 2009Working out climate sensitivity
I'm trying to get this all straight. So, we look back at T and CO2 correlations over time. Using the correlation relationships, recognizing that the correlations are confounded by obvious additional factors, we build probability distributions to estimate the likely correlation between just CO2 and T. I'm OK with that. Seems pretty straight forward. But stay with me here. Now, in a separate conversation we look into some principles from basic physics describing how CO2 molecules interact with IR. For instance, we know that CO2 absorbs well at characteristic frequencies, like most similar molecules. I'm OK with that too, straight forward stuff. But stay with me here. So there is a correlation between T and CO2, we can describe it with some set of probability distributions, AND, we know that CO2 interacts with IR radiation, or heat, which is also correlated with temperature. So, here is where I get lost. All of a sudden, because we know that Temperature is a covariate of IR radiation, and that Temperature is also a covariate of atmospheric CO2 concentration, we somehow get causality or "Forcing". Transitive causality in atomospheric science. Maybe for some it's "common sense", but with the myriad complex variables comprising atomospheric events, "common sense" doesn't cut it. In addition, the concept that there is a single "forcing" number contained within the probability distributions is offensive to my sensibilities as a scientist. IF..., and this is a big IF in my interpretation, this so-called CO2 forcing does occur, isn't it highly likely that it would vary in a more complex manner than a simple logarithmic function. I am new to this topic in the last year or so, and only recently have I begun to read the foundational work in detail. I am finding it really hard to swallow. -
Steve L at 05:33 AM on 21 November 2009Record high temperatures versus record lows
I don't have the data, but I'm guessing "no, the upper tail is getting shorter relative to the mean" from the fact that new record highs aren't yet exceeding the null expectation. Perhaps the distribution will continue to get less leptokurtic, but it's because the bulk of the temperatures is creeping up and eventually we'll see red dots higher than the line more and more often. I think this is interesting because the expectation of "more extreme weather" that comes with AGW might be interpreted as a flattening of the density function. I would be curious to learn whether or not the data as summarized above are actually relevant to the notion that weather will become more extreme. Is there a contradiction or, if not, what is the disconnect? -
Albatross at 04:51 AM on 21 November 2009Record high temperatures versus record lows
SeveL, thanks. You described what I was picturing, although has the tail for the max. temps not also become longer? Maybe someone who has the raw data could generate the PDF for the temperature data. I could try to do so, but don't know where to source the data. -
Riccardo at 04:48 AM on 21 November 2009The albedo effect
Henry Pool, given that you think that absorption is a confusing word and that the missing intensity at some wavelgths at the earth surface are an indication of higher reflectivity, belive me, i can't anticipate what your conclusions might be. -
Henry Pool at 03:33 AM on 21 November 2009The albedo effect
Riccardo, you have fallen in my trap. If you know the answers coming from my experiment, and if you say that the earth is a greenhouse then......what is my conclusion???? -
Steve L at 03:05 AM on 21 November 2009Record high temperatures versus record lows
I think I can picture the probability function changes described by the study (based on 24 hour periods, each standardized to the mean for that day of the year) -- the tail toward lower temperatures has shortened while the tail toward higher temperatures has stayed the same [affecting the kurtosis] and the bulk of the data have shifted slightly toward higher temperatures [affecting the skew of the distribution]. I don't know if this is what you (@19) mean. You write "rather than each day being +2C warmer" suggests that you might be talking about variance among days of the year rather than changes on a given day of the year. That would be quite a different way of looking at the data. -
Riccardo at 01:11 AM on 21 November 2009The albedo effect
Tyndall in 1859 did this kind of eeperiment for the first time. Since then it has been reproduced by many other. If each time we have to repeate two centuries of science, we'd be stuck at Galielo and Newton or maybe even Archimedes. -
Henry Pool at 00:27 AM on 21 November 2009The albedo effect
Really, we are going around in circles. Why not first answer me on 127? If I look at those graphs then there is really only a very small corner of earth radiation cut off by the CO2 at 14 um. It is not the surface area of the absorptions that is important, it is the width in um of the waveband lengths where absorption takes place (even the slightest absorption). This is where reflection (or scattering) takes place. Anyway; I have thought of the following simple experiment to settle this matter. Do you think it would work? If not, why not? Experiment 1 We have a glass vessel, about 1000 liters, flushed and filled with 80% nitrogen and 20% oxygen, representing the earth and its atmosphere at the beginning. We have a probe on the side, in the middle, connected to a thermocouple and a temperature recorder. We have a large heating element in the middle of the vessel. The vessel is closed from the outside. The outside temperature and humidity is kept constant, at all times. A measured amount of energy is released into the vessel. The resulting increase of the temperature in the vessel is recorded until it falls back to the base line. The area below the curve is measured. The measurements are repeated until a constant result can be reported. (A) We now double the amount of energy released into the vessel, this increase representing the doubling of energy released by human activity on earth from 3.5 billion people in 1960 to 7 billion people in 2009. The area below the curve is measured. The measurements are repeated until a constant result can be reported. (B) In the case of this first experiment, the result is predictable i.e. if you double the amount of energy released in a vessel you should find close to a doubling of the area under your graph. This already proves that Henry’s theory rather than a 25% increase in carbon dioxide may have some bearing on global warming. (For the time being Henry’s theory is still that global warming is caused by people releasing energy when flying, moving, cooking or just wanting to stay warm or cold) Experiment 2 Experiment 2 is exactly the same as experiment 1, but now the vessel is filled with air, which includes all 350 ppm or so carbon dioxide currently available in 2009 air. The results are C en D. What would be interesting for me to know is the difference between A and C and between B and D – in other words: if we release similar amounts of energy into the vessel, what effects, if any, does the carbon dioxide and the other gases present in air have on temperature retention inside the vessel? -
Albatross at 16:33 PM on 20 November 2009Record high temperatures versus record lows
Interesting study, got Anthony Watts all steamed up. I have not looked into the specifics, but I was wondering if anyone has determined whether or not there has been a statistically significant shift in the probablility distribution function/s (PDF)for the min. and max. temperatures? It is my recollection that AGW is going to manifest itself (or rather already has) in the shift of the PDF of temperatures, especially the tails, rather than each day being +2C warmer, for example, as many people tend to think. Anyhow, a PDF analysis might be more robust and insightful than the data contained the figures here. -
ejo60 at 14:16 PM on 20 November 2009Why is Greenland's ice loss accelerating?
@RSVP: The mixing of a fresh water pulse is described in a paper written by Detlef Stammer last year in JGR. To summarize, it takes a while before it is mixed and it mixes globally, not locally at suggested here. We are talking about time scales of 100 years or so. -
iskepticaluser at 13:33 PM on 20 November 2009Increasing CO2 has little to no effect
re comment 1 (HumanityRules), referring to apparent increases in radiation in the 800-1000 part of the spectrum in the Harries paper (the full version of which you can find through Google Scholar): on page two, 2nd column, that paper does indeed offer a potential explanation, viz. incompletely-cleared artifacts in the data (due to ice-cloud absorption). Considering the study is the first of its kind, its finding of reduced radiation precisely in the wavelengths associated with increased GHG concentrations remains remains highly suggestive, no? -
Alexandre at 10:21 AM on 20 November 2009Record high temperatures versus record lows
One detail I noticed on the UCAR page: there´s a special box for journalists. This is great. Communication of scientists with the press shoul be smoothed as much as possible. -
Riccardo at 08:25 AM on 20 November 2009The albedo effect
Henry Pool, it's not me that's eventually wrong, it's two hundreds years of physics of radiation. Instead, for you it's correct that the radiation missing at the earth surface does not show up in the reflected spectrum and it's not absorbed (absorption, for you, is the word that confuses people). Then not even energy is conserved in the process ... -
Tom Dayton at 06:57 AM on 20 November 2009The albedo effect
Henry, you wrote "I did try to look at that paper but it is something to do with testing in high pressures and high CO2 concentrations which cannot be related to what we are talking about here." Henry, you need to actually read the posts, not just skim them. I pointed you to not just that article, but I went to the trouble to tell you specifically which figure to look at in that article, and I explained specifically how it relates to "what we are talking about here." CO2's Raleigh scattering is inconsequentially small at its partial pressure in Earth's atmosphere, and more importantly any increases in its partial pressure (concentration) in the range of even the most horribly tremendous human-or-natural-caused releases would leave its Raleigh scattering still inconsequential. Look at that figure in that article. -
Steve L at 03:36 AM on 20 November 2009Record high temperatures versus record lows
RSVP: 1, actually there are probably fewer blue dots in the summer too (the news release attributes the pattern to warmer nighttime temperatures). 3, agreed, but I think self-interest is only one of several factors involved (religiosity, propensity to listen to talk radio, generally being set in one's ways, etc). Nobody has either agreed or disagreed with me regarding whether ratios or percentages are a better way to summarize the information. I'm surprised because I thought that might be the most substantive thing I've written in a while. -
cbrock at 03:25 AM on 20 November 2009Record high temperatures versus record lows
John @15, to stay sidetracked (sorry John C.), my father is in the "extractive industries" field--a professor of petroleum accounting at a Texas university, but having a physics background--and is constantly bombarded with the usual Fred Singer quotes from his colleagues. The SkepticalScience site has really been great at supplying him with ready responses to these sorts of comments. He's learned a lot and has a much deeper understanding of the issues. So great thanks to John Cook for taking all the time and energy to sort through the science and distill complex findings into clear and succinct summaries that the general public can understand. And for maintaining a site that is free of political ranting! I've not found a better site for this, and I've looked quite a bit. -
Mizimi at 02:33 AM on 20 November 2009What does past climate change tell us?
Chris# I think you may have typo'd here... "and the Greenland ice cap is likely committed to melt at atmospheric CO2 equivalents above around 280 ppm" or are you really letting us off the hook? -
Henry Pool at 02:25 AM on 20 November 2009The albedo effect
@Tom on 44, I did try to look at that paper but it is something to do with testing in high pressures and high CO2 concentrations which cannot be related to what we are talking about here. I think Riccardo is wrong, he does not understand what the gases are doing in the atmosphere when you see the sun's radiation on top of earth (before the atmosphere) and at sea level (below the atmosphere). This has been measured many times. Look at your own doc. Surely that difference (the radiation reflected), is what makes the bulk of earth's albedo? If you look at the sun's solar radiation spectrum then you can see that a bulk of UV is cut off, especially where the sun's curve is the biggest. -
Tom Dayton at 01:49 AM on 20 November 2009The albedo effect
Henry, when water snow falls it traps air in between the snowflakes. Accumulating weight of the snow on top compresses the flakes but does not squeeze out all the air. So the ice cores contain lots of trapped air, including CO2. -
Tom Dayton at 01:45 AM on 20 November 2009The albedo effect
Henry, many people have told you repeatedly that testing has been done. Just one example is a scientific paper I pointed you to, that you can read for yourself and so not have to take my word for it. I even told you where in that paper to look, so you don't have to read the whole thing. Yet you continue to write as if no one has pointed you to any sources. -
Riccardo at 01:14 AM on 20 November 2009The albedo effect
Terrestrial albedo is not determined by the atmosphere but mainly by the planet surface (oceans, lands, ice, forest, etc.) and clouds. As for the atmosphere, reflectivity in the true meaning is zero because the index of refraction is 1, apart from the forth or fifth decimal place. What matters, instead, is Rayleigh scattering by molecules. It depends, among other things, on concentration (hence mainly N2 and O2 give some, although small, contribution) and on the inverse of the fourth power of the wavelength (hence contributing in the blue-UV part of the spectrum). Any supposed effect on earth albedo must consider this good old (and yet undisproved) 19th century physics. -
John Cross at 00:18 AM on 20 November 2009Record high temperatures versus record lows
Just to show how easy it is to get side tracked I will throw in a data point that my father also doesn't seem to buy into global warming. We just don't discuss it anymore. While I won't give away his age, he remembers WWII quite well. My father-in-law doesn't believe in much these days RIP! Regards, John -
RSVP at 20:35 PM on 19 November 2009Record high temperatures versus record lows
1) From the graph, it is apparent that as you move to the right, the red dots are hugging the black line as they should. At the same time, extreme cold becomes rarer and rarer over time. Most people (out there) think of Global Warming as a general rise in temperatures. What it really means is Milder Winters. This fact was apparent in an earlier post that pointed to a link containing historical data from Greenland. It showed milder winters, with summer temperatures generally unchanged. 2) While you cannot know by the red or blue dots what extreme temperatures are behind them, this may not be important. The graph is useful and portrays what is really going on (given sound interpretation). 3) As far as father in laws, maybe it would be interesting to see a plot of belief in global warming (on a scale of 1 to 10) vs age. My sense is that younger people would tend to be more concerned, since they are more likely to be affected in their lifetimes. -
HumanityRules at 19:30 PM on 19 November 2009An overview of Greenland ice trends
I guess what I'm saying is that Chris has the fantastic ability to outline a scenario as though it is set-in-stone when in reality there is still serious debate about even the fundamentals. Hot off the press. Take temperatures. You would think its a simple case of looking at a thermometer and writing it down in a book. But maybe we haven't even got that right yet. Klotzbach, P. J., R. A. Pielke Sr., R. A. Pielke Jr., J. R. Christy, and R. T. McNider (2009), An alternative explanation for differential temperature trends at the surface and in the lower troposphere, J. Geophys. Res., 114, D21102, doi:10.1029/2009JD011841. Or the models we use are they accurately predicting reality Knorr, W. (2009), Is the airborne fraction of anthropogenic CO2 emissions increasing?, Geophys. Res. Lett., 36, L21710, doi:10.1029/2009GL040613. -
Henry Pool at 19:25 PM on 19 November 2009The albedo effect
Henry@Tom at #40 thanks very much for that explanation, that has always puzzled me a bit. If you are correct then there is no CO2 freezing up at the poles either? How could they have done core ice analysis and find CO2? -
Henry Pool at 19:21 PM on 19 November 2009The albedo effect
Henry@Tom 37/38 e.g. I have shown in my quote used in #28 (this is the one Steve is complaining about) that oxygen/ozone, water vapor and carbon dioxide are the ones that seem to cause the bulk of earth's albedo. If earth's albedo has increased (as has been shown by Palle et al 2008: see in the conclusion) then it is is logical to assume that this must be due to increases in carbon dioxide and ozone and water vapor. I have proven to you that these gas concentrations have indeed increased. The good news is: they will keep increasing. Now Tom admits: "To be clear, CO2 does reflect radiation at some wavelengths, but (this?) reflection is inconsequential for the Earth's current situation of global warming." At least we are making some progress here. The question now is: how do you know that the reflection of carbon dioxide is inconsequential unless you have done some testing? -
HumanityRules at 15:20 PM on 19 November 2009Record high temperatures versus record lows
Pico This maybe unrelated but there is certainly a link between El Nino and Eastern Australian weather. I've got a question on El Nino. Have they been more frequent since 1980? Does this graph from Santer suggest two El Nino in the 1980's and 4 in the 1990s? https://www.llnl.gov/str/JulAug02/gifs/Santer5.jpgResponse: There certainly is a link between ENSO and eastern Australia - I plan whether we go on a snow holiday based partly on whether we're in La Nina conditions (which leads to colder, wetter conditions at Perisher). -
Steve L at 15:18 PM on 19 November 2009Record high temperatures versus record lows
I think the point is that changes in local, extreme weather have different consequences than changes in regional, average weather, so looking at how extreme weather changes in response to climate change is valuable. It's important to compare models expressing what we think extreme weather will do to how extreme weather actually reacts. This might be one of the first papers to do this with a realistic null model (I don't know). In future, hopefully better alternative models can also be presented. Borrowing from your idea of looking at shorter periods, a model comparing rates of new records to rates anticipated for adaptation might be valuable. -
Steve L at 15:04 PM on 19 November 2009An overview of Greenland ice trends
Re 34: I don't believe in a lag, either. I believe that glaciers begin to respond to climatic changes very quickly but, as Chris points out, they don't necessarily come to equilibrium quickly or even approach equilibrium at similar rates. Re 33: I haven't read any of the papers listed in this thread and I'm unlikely to do so. It's completely unclear to me what you're trying to say by citing the ones you do. I assume there are also papers that suggest there will be greater rises in sea level. The question is, downgrade from what and upgrade from what? Generally accepted estimates of climate sensitivity to 2xCO2 have changed little over time, but there are papers suggesting more sensitivity and there are papers suggesting less. Maybe a good research topic would be to review predictions of expected sea level rise, too, and see how these have changed. You think uncertainty is underemphasized, but IPCC AR4 found sea level rise prediction to be so uncertain that it ignored dynamic changes. I think your opinion on uncertainty is unfounded. -
HumanityRules at 14:46 PM on 19 November 2009Record high temperatures versus record lows
It's interesting and to some extent fun but exactly whats the point? Given that temperature isn't a random system is there anything to be gained from looking for randomness. As can be seen from the graph highs and low do diverge after the 1980s to suggest warming but they also diverge in the 1960-1970 but in the opposite direction suggesting cooling for that period, statisical significance for both period would be interesting. To add to that I wonder what happens when, following a cold snap (1970s), you look for randomness in the distribution of highs and lows? Common sense would suggest you'd see more highs. An alternative analysis might be to analyse the data from the begining of each period (warming and cooling) to look for trends within that period although this would have the disadvantage of shorter time course. -
HumanityRules at 13:59 PM on 19 November 2009An overview of Greenland ice trends
Steve One more point on lag. This is from the Rignot paper's conclusion "We reconstructed the Greenland ice sheet total annual mass budget from 1958–2007. The ice sheet was losing mass during the warm period before the 1970s, was close to balance during the relatively cold 1970s and 1980s, and lost mass rapidly as climate got warmer in the 1990s and 2000s with no indication of a slow down. Hence, the temporal variability in mass balance is significant and closely follows climate fluctuations. " Clearly he doesn't believe in lag. -
HumanityRules at 13:30 PM on 19 November 2009An overview of glacier trends
David You may want to watch what you write on this website I got my wrists slapped for writing "outlandish comment" Chris It's funny I accuse you of confounding local and global and you accuse me of the same. Points i) and iii) did attempt to highlight specific local conditions something that should be irrelevant over an averaged global scenario. I have no problem with the general principle of warming air = melting ice. I have a problem with the degree to which the historical process is minimised by yourself in order to over emphasis what is occuring today. Take the use of the term accelerating retreat, used to describe the retreat from 1970s to the present. Technically accurate, suggestive of an extra ordinary process occuring over the past 2 decades but go further back in time and you realise what is happening is a return to a previous rate of retreat in the 1940-50 before the pause around the 1970's. -
Matt Andrews at 12:15 PM on 19 November 2009Record high temperatures versus record lows
Steve L @9, yes, that's what I meant. To me, comparing record high minima (night-time minimum temps) against record low minima - and, separately, record high vs record low maxima - would be much more significant than just high maxima vs low minima. Wonder if I can dig up the raw data and do that myself... -
HumanityRules at 12:01 PM on 19 November 2009An overview of Greenland ice trends
Chris i) I see you're reviews in post #2. I don't have time to read everything but essential these papers are using the same sort of data (archaeological, salt marshes etc etc) which Grinsted uses when looking beyond the sea gauge data. These have all the same problem that you have pointed out previously- local, sporadic etc etc. ii) Accepted. It works both ways. Grinsted graph shows higher peak temp in the MWP than in the year 2000. It there on the graph. iii) I'm not sure that the temp rise was very slow and prelonged. Sure the rise started in 600Ad and end around 1200AD but according to the Grinsted graph most of the rise occured over a much shorter time period. I have a real problem with the attempt to compared the rate say over the past 20years with an average rate over a period of 600years, it seems inherently flawed to me. Better would be to compare similar time periods. Obviously the scale on the Grinsted graph makes the following a little dodgy but still i think it gives good ball park figures. We agree sea levels have risen 18cmm in the 20th century. Lets pick a 100 year period around the MWP. let go for 1000-1100AD as this is the time of steepest rise on Grinsteds graph. Print the graph to fit A4 paper and you can probably measure about 10cm of sea level rise for that century. That puts the rate about half the average rate in the 20th century if you accept the 18cm figure. Are you now suggesting a 200-300year lag in sea level rise? So we are seeing sea level rise due to climate conditions from 1710-1810? Does that mean the 14cm rise in 20th century sea level rise which is anthroporgenic is due to mans activity in the 17th century? There seems a logic in consistency in this process #Steve It's an interesting point you make about Chris point iii). Another thing that had occured to me is that if the 1960-1970 represented and static and in some cases reversal of glacier melt than that offers the possibility that come the resumption of retreat post 1970s there is the possibility of an exaggerated bounce ice is cleared fro I aplologise for the poor posts they are usually rushed in the time between experiments and tend to try to cover too many point (like this one). But part of the problem is that I think this science is far from complete, often publications contain contradictory statements, expressing that uncertainty is a problem for me. I think there is much more uncertainty in this process something that is often expressed by many of the better authors themselves. But many other are more cavelier. Take one of Chris' reviews from #2 Church JA et al. (2008) Understanding global sea levels: past, present and future Sustainability Sci. 3, 9-22. Reviews have time and space to look at all aspects of a subject but this review doesn't mention uncertainty in relation to historical data, a very important aspect. How about this paper GEOPHYSICAL RESEARCH LETTERS, VOL. 34, 2007 Meteorologically driven trends in sea level rise Alexander S. Kolker Which claims to identify important meteorological factors that affect apparent sea level rises independant of global mean temperatures. This paper also "downgrade rates of warming induced sea-level change along Atlantic shorelines" Or how's about this publication GEOPHYSICAL RESEARCH LETTERS, VOL. 31, 2004 Ocean freshening, sea level rising, sea ice melting Peter Wadhams et al which also downgrades 20th century eustatic rises. -
Tom Dayton at 11:48 AM on 19 November 2009The albedo effect
Henry Pool wrote "Apart from the radiation trapped and reflected by CO2 we also sit with the problem that cooling may occur higher up the atmosphere (CO2 freezes at -40 degrees C I think?). Obviously where it freezes it must reflect a lot more sunshine. (compare water vapor with water droplets - I am sure the droplet reflect more sunshine." No, CO2 does not freeze in the Earth's atmosphere. It does not even form liquid droplets. The partial pressure of CO2 in the Earth's atmosphere is far too low. "Partial pressure" is the pressure of CO2 if it were the only gas in the atmosphere. Since the total pressure of the Earth's atmosphere is (by definition) 1 atmosphere, and CO2 is on average 0.038% of the atmosphere, CO2's partial pressure in the Earth's atmosphere is on average 0.00038 atmospheres. At the higher levels of the atmosphere where the temperature gets low, the partial pressure is drastically lower even than that. You can see from CO2's phase diagram that it cannot possibly change from gas to liquid or solid at those pressures--not even at the Earth's surface, let alone high in the atmosphere. -
Steve L at 11:30 AM on 19 November 2009Record high temperatures versus record lows
Proposed new website: "Father in-law Science". Matt @7, do you mean you'd like to see record high daily minima and record low daily maxima? I think I agree -- let's look at nighttime and daytime temperatures separately. -
Craig Allen at 11:06 AM on 19 November 2009Record high temperatures versus record lows
It would be interested to see a similar analysis for Australia. The heatwave and other temperature records of Victoria and South Australia are being blown away year after year. Something really screwy is happening. Now we are seeing a heatwave in Spring that exceeds the record from a few years ago for summer heat waves.Response: It's funny you should mention that - Meehle 2009 refers to a similar study on record highs/lows being done for Australia. I scratched around for it but it appears to be not yet published - will add it to the It's Freaking Cold page when it comes out. -
Matt Andrews at 09:55 AM on 19 November 2009Record high temperatures versus record lows
Fascinating study, and well delivered - thanks. What would be especially interesting would be to see the data on record high maxima versus record low maxima, and particularly record high minima versus record low minima. -
Steve L at 08:30 AM on 19 November 2009The albedo effect
Re 36, Henry: how can longwave radiation of the wavelength relevant to CO2 increase at the Earth's surface if CO2 is reflecting that out to space before it gets to Earth? I'm not going to go to much effort with you unless you're willing to think about this. In my opinion, you're not being taken entirely seriously here for the following reasons: 1. You make comments based on your own vague interpretations, 2. When asked for citations you make it hard for people to see what you mean and/or you cite things that don't make the point you pretend they do (both exemplified by the Astrophysical Journal abstract you quote in #28), 3. You seem to think that other people have to do things for you -- as SNRatio says, the burden is on you to be convincing, especially given all the evidence that there is an enhanced greenhouse effect (Venus is a good example of a high albedo but hot planet that you would have to explain). I think you can be more effective if you try to adjust your approach. -
Riccardo at 08:30 AM on 19 November 2009Why is Greenland's ice loss accelerating?
One more number to put the extra inflow into context. The 400 GTon/yr correspond to 1.3*10^4 m3/s which in turn translates into 0.013 Sv. Both the Labrador current and the east Greenland current are several Sv. -
Steve L at 08:13 AM on 19 November 2009An overview of Greenland ice trends
Hi Chris, I think you've been quite clear that response time is about re-establishing equilibrium (ie the full response). I don't know how well HR distinguishes this from lag times, which I think for him are periods of nothing happening (no detectable beginning of a response). But I can't be sure, because I don't find HR's writing to be very clear. One thing I thought I should ask about your point (iii) above, surely as the amount of available ice left to melt decreases, the rate of sea level rise will decrease. We may be far from running out of ice, but it seems to me that ice retreating up mountains is harder to melt, and even a linear response in sea level could be expected from that. Or perhaps this is where the geography comes in, as land gets steeper as you go up? Maybe I should have limited my comment to: Can we say at what point in a steadily warming world sea level rise stops accelerating? -
Tom Dayton at 07:33 AM on 19 November 2009The albedo effect
To be clear, CO2 does reflect radiation at some wavelengths, but reflection is inconsequential for the Earth's current situation of global warming. -
Tom Dayton at 07:31 AM on 19 November 2009The albedo effect
Henry Pool, you wrote "as I have clearly shown you, over and over again I should say, CO2 also causes reflection of sunshine." That is incorrect, as several people repeatedly have told you," and even have referenced peer-reviewed scientific papers that you, yourself, can read. "Reflection" is a specific physical phenomenon that is qualitatively different from absorption-followed-by-emission. -
chris at 06:40 AM on 19 November 2009Record high temperatures versus record lows
mea culpa - formatting errors: I wrote two posts too quickly, and have messed up a blockquote here: http://www.skepticalscience.com/An-overview-of-Greenland-ice-trends.html post #31 and a bold text closure here: http://www.skepticalscience.com/An-overview-of-glacier-trends.html post #24 my very bad! Is there any way of resetting the formatting to the default at the end of each post so that careless numpty's like me don't keep messing up the formatting?Response: Chris, I've manually fixed those two comments. There's probably some clever code I could write to automatically fix stuff like that but I'm too busy (and lazy) to dream that up at the moment so I'll just throw a bandaid on the problem for now :-)
BTW, I've tried emailing you several times with no reply. Do you no longer use the o2.co.uk email address you signed up with or are you just ignoring me?
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