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Comments 111151 to 111200:

  1. Weather vs Climate: Watch the waves, miss the turning of the tides
    Iciattaglia, we all know that. Noone thinks that the earth itself is in danger of expiring. The climate change that concerns us is this climate and its stability. This climate phase has allowed humans to thrive and flourish because it suits the temperature range we can live in comfortably and it suits the kind of plants that sustain life. Our kind of abundant life, not the kind of life that just survives in ice or fire or sitting atop an undersea volcano. Your argument is about geology and time frames of many millions of years. We're concerned about biology and timeframes of centuries or millennia.
  2. Urban Heat Islands: serious problem or holiday destination for skeptics?
    I should also point out the UHI is affected by wind speed. I can think of well-sited stations where the prevailing wind off the sea means that no how big the urban center beside it is, there is no chance for heated air from the city to affect the bulb. BP's assumption for correlating UHI to change in urban size are too naive to be valuable.
  3. It's Urban Heat Island effect
    Hadfield - you might like to look at Are Temperature Trends affected by Economic Activity? for a starting point if you want reference to the 2004 effort. For the 2008 version, then an analysis was published here
  4. How we know an ice age isn't just around the corner
    I think there is a bit o a misconception here in regards to rate o climate change.... coming outta the last glaciation, the rate o change was at times SEVERAL orders o magnitude above the current trends.... this is where the tipping point hypothesis have come from! http://www.chmi.cz/HK/OK/clivar-cz/PRA_posters/clivar_poster_pages2.pdf http://www.gisp2.sr.unh.edu/DATA/fancy.html http://math.ucr.edu/home/baez/temperature/
  5. It's Urban Heat Island effect
    Hadfield does have a point. The summary paper linked to has arguments against several of the explanations presented here. Have there been any responses to their paper that address these concerns?
  6. It's the sun
    sun tzu @ 580 No harm in being a layman in anything. All of us were at one time. Remember the atmosphere is layered, like an onion. Forces that act on one layer may, or may not, act upon an adjacent one. Increasing CO2 exerts its main influence in the upper troposphere, the lowest layer, causing it to warm. Lack of energy being transmitted upward from the troposphere to the stratosphere means the stratosphere cools (which is measured by satellites). When layers cool, they can compress, thinning somewhat. Recent UV output from the sun has been declining, causing the thermosphere, one of the outer layers of the Earth's atmosphere, to compress downward, to a record low thickness. The net effect of this compression is less atmospheric drag on our communication & research satellites in low Earth orbit (which extends their service lifetime - bonus!). Note that changing energy levels of the various layers of the atmosphere or their thicknesses has no effect on the mass of the column of air above any point on the Earth (which is what determines the local air pressure). Atmospheric physics is a complex area of study. Even experts in it get confused sometimes (or tripped by the D-K Effect). For an introductory starting point, try start here first, then go here, then go here to figure out where to go next. Wiki, surprisingly, is a good source as well. Once you know what to type in, anyway (Catch-22: you have to know enough to search for what to learn about next, but how do you search if you're a complete beginner?). Hope this helps, The Yooper
  7. It's the sun
    http://science.nasa.gov/science-news/science-at-nasa/2000/ast30may_1m/ Apologies for spamming the forums! heres one source that discusses the low earth orbit/atmospheric friction/ solar activity
  8. It's the sun
    Eg. atmospheric density affecting solar absorbtion rates
  9. It's the sun
    What I am trying to articulate (badly) is the overall constitution of atmospheric gas density and thermal retention - is there a correlation there?
  10. It's the sun
    I have been reading many of the posts here and must admit I am a layman in terms of climatology, however, has anyone looked into comparing the density of atmospheric gasses/atmosphere/atmospheric ceiling over time?. As I understand it, Low earth orbit debris has been increasing due to a lower atmospheric ceiling, and if it is due to a lower ceiling/upper atmosphere density has the atmosphere increased in pressure or been absorbed somwhere else? (co2 into the ocean possibly? methane reacting with UV?). Now if the aforementioned where true, would it not be a similar scenario to how a refrigerator functions in that the denser gas acts as an insulator retaining the heat then as it is decompressed/expands it cools by realising the heat energy (like an aerosol can)?.. as i have previously stated I am a complete novice and apologise for not being able to submit any sources, this comment is intended more as food for thought than anything else and will most likely barking up the wrong tree altogether!
  11. Carbon dioxide equivalents
    Re: TOP
    It is an important distinction because CH4 is a much more powerful GHG. CO2 residency can be reduced by planting new trees. CH4 can't. Big point.
    I understand your first point. Please keep in mind that:
    1. While on a molecule-for-molecule basis methane is about eighty times stronger greenhouse gas than carbon dioxide due to it's much smaller concentration in the atmosphere, the greenhouse effect attributed to methane is 4-9% of the whole, whereas that attributed to CO2 is 9-26%. Thus, the Radiative Forcing (W/m2) of methane is 0.48 while that of CO2 is 1.46. And keep in mind that the concentrations of methane (1745 ppb) are a tiny fraction of that of of CO2 (390 ppm). Yes, the methane will provide a modest increase in RF during its 12-year residence time before it degrades into CO2. But the warming coming from that CO2 concentration will (like the Energizer Bunny) keep on going, and going, and going... And thus rendering the need to sequester the methane moot (because it presto/chango converts to CO2). 2. AFA planting trees. Sure. Yup, in the tropics, it makes sense. But in temperate and more northerly climes, reforestation actually causes the new forests to become part of the warming problem. Because the new tree canopies are darker, they effectively change the albedo of the newly forested area, causing more heat to be retained near the ground. See here and here for a nice discussion.
    And atmospheric aerosol pollution hasn't stopped per se so much as it has leveled off. CO2 concentrations have been doing their Icarus thing. Hence the emergence of the CO2 warming signal from the cooling effects of aerosols. Aerosols are still reducing the warming effect of CO2, not stopping it. Hence, we are buying the current generation time, at the expense of all future living generations. Unrestrained BAU will make this place a living H-E-Double-Hockey-Stick for our grandchildren's generation. Which will continue for centuries.
    States like Wisconsin that once were huge forests and now have a lot of worn out farm land are another target for trees.
    Really? Have you BEEN to Wisconsin lately? Dude, I drive all across Wisconsin and Northern Michigan, daily. Every viable plot of land with soil decent enough for growing is under cultivation. The rest is either houses, swamps or stands of crapwood, like popple or jackpine. All the good soils were "expatriated" to Illinois, Indiana & Ohio by some white lumpy rainish-stuff millenia ago... The remnants of the once mighty forests that stood here (the stumps of which measure up to 8 feet across) are still visible in places. Those giants took many centuries to reach maturity in these poor soils. Reforestation going on now focuses on the fastest-growing pines, which are soft and unsuitable for building purposes (they use them to make paper, toilet paper and particle boards of various sizes & thicknesses). The CO2 drawdown potential of softwoods vs hardwoods is pretty low. The 6 foot-thick oak in my backyard somehow escaped (probably because all of the old hardwoods here are natural bonsai's and don't grow that high compared to their more southern relatives) the loggers of the 1800's (some of them my ancestors) and is estimated to be about 450-500 years old. Lotta board feet, but not useful for Carbon Capture & Sequestration purposes. ---------------------------------------------------------------------------------------------------------------------- Re: RSVP
    I am not sure China shares any more guilt here than those who consume their products...(which could be almost anyone).
    Excellent point. In an intertwined, global, consumeristic society, all are guilty. You guys got me all fired up. I hates that. The Yooper
  12. How we know an ice age isn't just around the corner
    A scientist called Ruddiman has a book speculating we started altering the climate with early farming thousands of years ago. It appears humanity has been heading off an ice age thats going too far too fast as in #17. An unconscious deliberate experiment or just chance?
  13. How we know an ice age isn't just around the corner
    GC - once again - RATE of change is what is more important. Maybe warmer would be better in long term but only if we get there slowly. I would like some explanation from you of why you think rate doesnt matter.
  14. Sea level rise: the broader picture
    HR at 56 YOU are comparing the 5.4 mm local rise to global 3.3 rise and saying it is similar to global changes from 1.8 to 3.3 mm/yr, not Ned. You are comparing apples and oranges and using a single standard. As I said, we EXPECT local changes to be more varied than global averages. Therefor 5.4 at a local site is comparable to 3.3 as a global average. We EXPECT global averages to be stable. Thus the global figure changing from 1.8 to 3.3 is significantly different. Even though these two data sets are similar in magnitude the meaning of the changes is different. Because of noise and other factors, single site data has more variability than global data does. You cannot use the same standard to compare two global averages that you use to compare a local point to the global average. It is often confusing to people who do not work with data all the time when there are issues like this. Even people who work with numbers all the time make mistakes. That is why we rely on experts to interpret the data. The experts have figured out how the data can be compared. Dougs post is a reasonable summary of expert opinion.
  15. Arctic sea ice... take 2
    Peter Hogarth, What an impressive video!!! It is like watching a dying beast gasping for breath, and flailing around to hang on to some life. Very emotional and unscientific, of course.
  16. How we know an ice age isn't just around the corner
    For those who fear a return of the Laurentide ice sheet, why is it not obvious that the correct response would be something like this flowchart a) Be carbon neutral for thousands of years b) If ice sheets start growing, burn some carbon - maybe 5 to 10 ppm increase in CO2 c) Continue to monitor ice sheets, return to (b) In other words, with our capability to dig up fossil fuels and burn them, we can *easily* dominate the Milankovitch cycles. The danger is going too far the other way, which we are near to doing. Recall that the "normal" interglacial CO2 concentration is 280-300 ppm. We can hold off any natural cooling by keeping CO2 at some slightly higher level, probably 320-350 ppm. Note that the rate of burning fuel to hold that range of CO2 concentration would be very low, so conventional fossil fuel reserves would last darn near forever (and we could mine methane hydrates after that - probably a few million year's worth, after that, the sun is warmer ...) Our mad dash to higher CO2 levels (currently 390 +2/y) might be great for Jurassic flora and fauna (if we had any) but is likely to be a significant extinction event for current species.
  17. Carbon dioxide equivalents
    And yes it is hopeless, except that God only left so much fossil fuel on this Earth (probably for this very reason).
  18. Carbon dioxide equivalents
    michael sweet asks... "How does this relate to DEMOCRACY for those of us who are not paranoid?" Not paranoid as much as considering how technically capable your average politician may be.
  19. Carbon dioxide equivalents
    JMurphy said... "Anyway, although China is now the largest emitter of CO2..." I am not sure China shares any more guilt here than those who consume their products...(which could be almost anyone).
  20. Arctic sea ice... take 2
    From the main essay:
    As you might imagine, thick ice takes a lot more heat to melt, so the fact that it is disappearing so fast is of great concern.
    I just wanted to check... I presume the big reason for this would be that it is denser -- more compact as the air has been squeezed out of it. Another reason would be that through previous summer seasons the saltwater has been drained out of it -- as saltwater has a lower freezing temperature -- leaving rotten ice -- which with cycles of being compacted and drained each summer after perhaps two or three years will be pure enough that you can drink the melt water -- implying a higher freezing point.
  21. The surprising result when you compare bad weather stations to good stations
    Omnologos, you are making rather extraordinary claims. As discussed on the current page, in more detail on the intermediate version, checked against other readings to examine the UHI effect, and finally examined in detail for surface temperature reconstruction errors, there is no evidence of microsite or UHI contamination causing the observed warming trends - they are not spurious. You seem to believe otherwise, stating that perhaps "...the upwards trend can't be ascribed to an actual "warming"", or that "...maybe there is no trend.". Then show it. There's a large body of peer reviewed work demonstrating that there is a warming trend as shown in the surface temperature records; if you want to claim otherwise then I suggest you demonstrate it. Vague insinuations about data quality don't disprove warming, especially given the repeated analyses that validate the data. "Extraordinary claims require extraordinary evidence" - Carl Sagan. You've yet to provide any evidence whatsoever...
  22. Carbon dioxide equivalents
    TOP, have you put in a quote for planting trees in the Sahara, or do you have some figures we can all see which would show how viable a proposition it is ? I also notice that Wisconsin is presently 46% forested and is also important agriculturally, especially in the dairy industry. How much of that do you think they should give up so that they could plant more trees ? And if you reckon that "CO2 would drastically increase from today's numbers" if the "world emitted GHG per capita like China", you obviously agree that it would be far, far worse if the world emitted at US rates, I suppose ? Actually, it's a shame that the world DOESN'T emit at China's rate.
  23. Urban Heat Islands: serious problem or holiday destination for skeptics?
    Thanks, Philippe and muoncounter. The method used here (modeling a UHI bias based on log2 population change) doesn't seem super-convincing to me. But since BP proposed it, I thought I'd work out the quantitative implications, using a more realistic framework than the assumption that population increases uniformly everywhere. muoncounter, I agree on the "saturation" thing. But I think the bigger problem is in extrapolating the model in the opposite direction. Do we really expect a large UHI effect associated with the four doublings from 1 to 16 persons per km2? Sixteen persons per km2 is still a very sparse population. Bottom line, though ... even if you accept BP's model, you only get 3% of the global temperature increase coming from UHI.
  24. The surprising result when you compare bad weather stations to good stations
    Some here seem to have a problem with Menne et al themselves (a case of being more royal than the king, perhaps). May I quote again: "The reason why station exposure does not play an obvious role in temperature trends probably warrants further investigation" If the answer were e.g. "it's the precision", perhaps Menne et al would have mentioned that without suggesting any "further investigation". As just written by @Dappledwater, the "obvious" result has been contradicted by the "surprising" one. That can only mean there is more food for our scientific curiosity. If on the other hand we are just obsessed with countering other people's arguments on the basis of them being deniers or skeptics or anything else, well, there goes the curiosity, and there goes the science. BTW, @Tom Dalton: you have completely misinterpreted my remarks. Please don't waste any more time with...shall I say it...reductio ad absurdum. Of course even if there were no warming trend, it's just US stuff we are analyzing, etc etc.
  25. Carbon dioxide equivalents
    Yooper Which then has a residence time on the century timescale. Actually surprised and disappointed you nit on this one. It is an important distinction because CH4 is a much more powerful GHG. CO2 residency can be reduced by planting new trees. CH4 can't. Big point. Your points about the thinning of the haze about corresponds to the drive to reduce pollution. I remember driving in rush hour traffic where you could gag on the fumes. And there was the acidification of lakes in the East. That has all stopped in your time frame and now we have another problem, but one with a simple solution. Plant trees. JMurphy I could see where a Londoner would have trouble with trees in London proper. But then London isn't the only treeless place on the planet. Look at the Sahara. Big tree farm possible there. Anyplace you have water and sunlight you can grow trees. No need for doom and gloom about places to plant trees. I have a motto, "Make hockey sticks from trees, make trees from hockey sticks." If you look at the Western US you will see a lot of logged out areas. There is another prime candidate. States like Wisconsin that once were huge forests and now have a lot of worn out farm land are another target for trees. In addition to China burning a lot of coal (you can see the plume of CO out over the Pacific by satellite) they are contributing to the deforestation of the Amazon in order to grow soybeans and other foodstuffs. Huge farms have been created in what was once rain forest. Since China is a growing economy and things are constantly changing there, it should be the prime target to implement improvements. But while they may have the technology, they aren't using it. Per capita doesn't work with China or anywhere else. A small town in China is 4 million people. If the entire world was emitting GHG per capita like China, CO2 would drastically increase from today's numbers. Bad suggestion. Adding India to the loop would be even worse. China has no choice but to look to renewable energy. At the current rate of coal mining they will be out of coal in 50 years. They take a long view.
  26. Urban Heat Islands: serious problem or holiday destination for skeptics?
    #20: "calculated the number of doublings of population density for every grid cell" Ned, Nice work. But I wonder: Wouldn't the UHI become, in essence, saturated? Once an area became sufficiently 'urban', would each statistical doubling of its population actually add twice as much 'urban heat'? So wouldn't the calculated effect based solely on the number of doublings overstate the UHI?
  27. Antarctica is too cold to lose ice
    barney2022, the volume of Antarctic ice is decreasing. Obviously that is the 'most important' issue overall, but the article above explaining WHY the ice volume is now in decline is certainly also relevant... despite involving processes which have existed for a very long time. Also, you say "cooling that is taking place in this region of the world"... actually, Antarctica has warmed considerably in the past few decades.
  28. Antarctica is too cold to lose ice
    To answer Barney's question, no. Antarctica is experiencing a net loss of land ice. There is also a slight increase in Antarctic sea ice, but that's a different subject (and it's not caused by "cooling" in any case, since the southern ocean is actually warming). See Is Antarctica losing or gaining ice?
  29. Antarctica is too cold to lose ice
    Forget ice slides and ice shields, that has been happening for millions of years. The question is: Is the Antarctic getting larger because of the cooling that is taking place in this region of the world? Is ice getting larger in this area?
  30. Carbon dioxide equivalents
    TOP, firstly, where do we put all those trees and crops ? Where I live in London (and the South East of England in general) there doesn't appear to be much available land to give over to all those trees and crops - how many/much will we need ? Where do you suggest we put them ? Secondly, who, exactly, hasn't 'targetted' China ? Who HAS been targetted and by whom ? Anyway, although China is now the largest emitter of CO2, that is only a recent occurrence and they are only just ahead of the US, while having four times the population of the US. Per capita, they are well down the list (only just in the top 100), and far behind the US, Australia and Canada, for instance. China are also only just above the US in emissions of ALL GHG. But again, per capita, they are well down the list of offenders. As for coal, China may well use twice (maybe even three times) as much coal as the US, but don't forget that population, and therefore per capita, difference. China are also increasing the difference between themselves and the US in the use of renewable energy.
  31. How we know an ice age isn't just around the corner
    @ Ann #10. "or attributed to completely other causes" ... such as 'It is God's Will'. The move will be away from skepticism to fatalism.
  32. The surprising result when you compare bad weather stations to good stations
    omnologos, you seem to believe that "good" and "bad" station placement is an experimental independent variable, with anthropogenic global warming theory providing strong reasons to expect the "bad" condition to display a different temperature trend than the "good" condition. Therefore you think that indistinguishability of the good and bad stations' trends is evidence against anthropogenic global warming theory. You are wrong. Anthropogenic global warming theory never, ever, has made different predictions for "bad" stations than for "good" stations. Even if there had been a difference in trend between those two classes of stations, that difference would have had no consequence for global warming theory. You should notice that not even Watts & Co. have made the claims that you are. That's because your claims are nonsensical. The only reason Watts & Co. were making noise about station siting was their claim, without any theoretical justification whatsoever, that the trend really is zero, and that the apparent trend is an artifact of bad station siting. Even that hypothesis of theirs was not a hypothesis of anthropogenic global warming being expected to cause a difference in trend between "good" and "bad" stations.
  33. Carbon dioxide equivalents
    RSVP, That statement clearly means that if I say carbon dioxide equivalents (not counting the effect of aerosols) and a policy maker thinks I mean carbon dioxide equivalents (counting the effect of aerosols) the policy maker might misunderstand what I said. Since the costs and benefits are different the decisions made are likely to be different. How does this relate to DEMOCRACY for those of us who are not paranoid?
  34. Carbon dioxide equivalents
    "There is a real potential for governments and policy-makers to misunderstand and mis-apply information..." Good thing most of the world is sold on "DEMOCRACY". What exactly does this statement imply, McGrath?
  35. Weather vs Climate: Watch the waves, miss the turning of the tides
    I remember reading a text on physical climatology a comparison aimed at representing the temporal dimensions of climate and climate change thus conceived: Suppose that the climate is represented by a natural forest and man is an ant. A natural forest is usually composed of areas where the plants are denser and some clearings, then to the edge of the forest clearings are increasingly extended until the wood ceases. Imagine that the ant is on its way through the forest and try to figure out where it ends. Whenever the vegetation thins out and is a grassy bushes or an open space the ant will be led to believe she get to the forest’s end. The same thing would happen to us if we wanted to assess climate change of the Earth with the lifespan we cross and judging the climate change on the basis of our "time meter”
  36. Carbon dioxide equivalents
    Re TOP @ #4 above:
    Methane oxidizes to CO2 in roughly ten years. That is not long lived.
    Which then has a residence time on the century timescale. Actually surprised and disappointed you nit on this one. Inre: Aerosols helping counter the GE of CO2 see here as well as here and here for a better discussion and background. The Yooper
  37. Carbon dioxide equivalents
    The obvious solution/use for higher CO2 levels is man made absorption via planting trees and crops where no trees or crops now grow. It is interesting that China hasn't been targeted as a GHG emitter. They use twice the coal that is used in the US. For the most part it is burned without the pollution controls used in the US. Perhaps this is a good thing as the SOx aerosols help counter the increase in CO2. "...long-lived greenhouse gases such as methane" Methane oxidizes to CO2 in roughly ten years. That is not long lived.
  38. Philippe Chantreau at 23:41 PM on 1 September 2010
    Urban Heat Islands: serious problem or holiday destination for skeptics?
    Interesting Ned. Thanks for your work. Once again, this is the stuff you'd expect "skeptics" to do themselves if they were sincere.
  39. The empirical evidence that humans are causing global warming
    Arkadiusz - Your postings are often long, with multiple references, and clearly show that you are doing some research and digging into sources. However, here, as in many previous postings, I find myself unable to determine what your point is. It's something about mid-century records of carbon and temperature, but are you asserting that there are (a) problems with one or more of the records, (b) issues with isotope methods, (c) anomalous temperature swings not congruent with current theories, or (d) something else entirely? I cannot tell! It would be very helpful if you could summarize or otherwise clearly state what your concern is in these postings.
  40. Urban Heat Islands: serious problem or holiday destination for skeptics?
    OK, so I thought about this some more last night, and did some calculations this morning. According to Berényi Péter, the urban heat island (UHI) effect causes a spurious trend of +0.2C to +0.3C per doubling of local population. If the population around a point went from 1000 people in 1900 to 8000 people in 2000, this (according to BP) would bias the true warming trend (if any) by +0.6C to +0.8C/century at that location, because the population doubled three times during that period. To determine the magnitude of this effect for the globe as a whole, it's not appropriate to use the overall global increase in population. You need to look at it spatially -- adding two billion people to areas that are already densely populated would have a relatively low impact, but adding the same number of people to sparsely populated areas would have a very large effect (because it would produce many more doublings on average). So, I downloaded the global 2.5-minute gridded population density data set from SEDAC. I did this for 1990 (the earliest year available) and 2010. I then calculated the number of doublings of population density for every grid cell (there are 30 million grid cells -- the data set doesn't include areas north of 85N or south of 58S, which are essentially uninhabited).[1] I then weighted each grid cell based on the cosine of its latitude. The weighted mean number of doublings of population density (1990-2010) is 0.050. Adjusting for the excluded areas at the north and south poles brings this to 0.046 doublings per 20 years. If this number seems small, consider that most of the world is covered by ocean. In addition, much of the land is essentially uninhabited (think of Antarctica, Greenland, various large deserts, much of Siberia, etc.) Having no population, these areas have of necessity experienced no doublings of population, and thus no UHI. Combining this global mean of 0.046 doublings of population density from 1990 to 2010 with BP's claimed UHI effect of +0.2C to +0.3C per doubling gives a UHI bias of +0.046 to +0.069 C/century worldwide. Over the same period, the global land/ocean temperature trend is around +1.7 to +1.9C/century, depending on which metric you use. Thus, using the "Berényi Method" for estimating UHI, over the past two decades we can say conclusively that the UHI effect has accounted for approximately 3% of the observed global surface warming trend. ------------ [1] To avoid numerical calculation issues involving 0, I recoded all grid cells with <1 person/km2 as 1.
  41. The surprising result when you compare bad weather stations to good stations
    To quote you, omnologos: The "surprising result" shows (a) that "good" or "bad" is not a relevant way of categorizing stations regarding warming trends, in other words the work done by surfacestations.org is irrelevant in that respect OR (b) that the warming trend is spurious. The answer is (a), "not relevant", since the placement issues discussed affect offsets/accuracy, not repeatability/placement. Subset analysis clearly shows that the warming trends occur irrespective of subset selection, and are not spurious.
  42. The surprising result when you compare bad weather stations to good stations
    Omnologos - The so-called "good" and "bad" station identifications from Watts reflect adherence to placement guidelines intended to ensure accuracy, adherence to ground-truth, minimal offsets between the station temperatures and local conditions. As stated before (repeatedly, by several people) trend analysis of anomalies (changes) is not dependent on accuracy, but rather on precision, repeating the measurement the same way every time for each station. Fixed offsets, as addressed in the placement guidelines, are completely irrelevant for anomaly trends - they're removed as soon as you look at the differences over time. So what does this mean? It means that Watts "good/bad" labeling is not terribly relevant for trend analysis. There does seem to be a small difference in the range of temperatures between the so-called good and bad sites; the "bad" sites show smaller temperature swings and slightly less warming. Perhaps the 'air-conditioners' or other issues with some sites are insulating the stations from full temperature swings. But when you get down to the actual numbers, the charts above, it just doesn't make a difference in the trend data - the warming trend is not spurious. If you (as you have been doing) assert that it does make a difference, then you should calculate a significant trend difference statistic between subsets of the stations and show it.
  43. Arkadiusz Semczyszak at 23:11 PM on 1 September 2010
    The empirical evidence that humans are causing global warming
    naturanych = natural - sorry
  44. Carbon dioxide equivalents
    Aerosols are in itself a pollution that is supposed to be avoided. The geoengeneering that counts on them has side effects and is not considered to be a safe solution to the warming. Its inclusion in the total CO2e figures could lead to unwanted incentives.
  45. Sea level rise: the broader picture
    I will, time (and space) permitting, attempt to discuss variations from these trends, and the satellite altimetry record (Ken, BP), separately.
  46. Sea level rise: the broader picture
    Berényi Péter at 11:03 AM on 31 August, 2010 Sorry about the late response. I hope the following is useful. First, let us look at the comment on the New York Tide gauge data that Peter B selected (from NOAA historic tide data). The overall New York linear trend is 2.8mm/yr over the entire period, though there is a short gap. This is relative sea level, relative to the local land. We need to correct this data with an estimate of local GIA (Glacial Isostatic Adjustment, or post glacial rebound) for any vertical land movement. Peter B correctly states GIA in this area is still being affected by recovery from the the last Glacial Laurentide Ice sheet “forebulge collapse”. PBs image gives us little detail but his statement that New York GIA is negligible is not supported by several lines of evidence. If we look at: Figure 1, modeled GIA, image from Horton 2009. This shows output of a global GIA model (ICE-4G (VM2), Peltier 1998) looking at the US. Horton suggests there is good agreement with sea level data from the US North Eastern coast. The updated ICE-5G (VM2) model is given in Peltier 2005 (see figure 21, the coastline near New York runs somewhere beteen the 0 and -2mm/yr contours). From the updated GIA model Kolker 2009 gives New York GIA correction as -0.85 to -1.64 mm/yr. This means the land is tilting downwards and thus relative sea level rise rates would appear higher. We can also estimate GIA from direct GPS measurements made over several years as in Woppelmann 2009. Background for the North East of the US is given in Sella 2007 below which uses GPS derived vertical references using 362 GPS sites across US and Canada to estimate GIA (in good agreement with the models). For specific detail on New York Snay 2007 gives -1.35mm/yr for the nearest Geodetic GPS station vertical velocity (14.5km from the New York “Battery” tide gauge) but with high error estimates, as there was only 4 years of GPS data 2001-2005, at that time. There are now over 1600 GPS Continuously Operating Reference Stations (CORS) - as of end 2009, so we expect detail to improve and std deviation from older individual stations to improve as Woppelmann 2009 indicates for tidal stations near New York. Using the 2007 GPS estimate of GIA we get an absolute MSL (Mean Sea Level) rise of 1.45mm/yr for New York over the past 150 years. Using the GIA model value we get 1.56mm/yr. We can also estimate GIA from late Holocene Geological RSLR (Relative Sea Level Rise) data from before any 20th Century (or potential Industrial period) acceleration and subtract this from the tide gauge records, as in Engelhart 2009, which gives another independently derived GIA estimate and overall MSL value for the New York tide station of around 1.8mm/yr. If we use the same overall measured baseline RSL tidal value of 2.8mm/yr instead of the 3mm/yr Engelhart uses, we get an MSL value of 1.6mm/yr overall. The agreement is good. A related and useful recent paper on salt marsh derived Sea Level history is Kemp 2009. Here estimates of Mean Sea Level rise in North Carolina are given and placed in the context of other data from several sites in the NE US. The agreement with the global values from Jevrejeva 2008 and Church and White 2009 is good, and the small latitudinal variations are of note. Getting back to NY, using the GPS derived value of GIA to correct the tide data from New York, and comparing the corrected data with Jevrejeva 2008, we get: The offsets are for convenience. Second order trend fits are a little different, (I also get slightly higher NY acceleration values than BP even after corrections) but within each others error bounds. The overall background acceleration is apparent.
  47. Arkadiusz Semczyszak at 22:54 PM on 1 September 2010
    The empirical evidence that humans are causing global warming
    “terrestrial-derived atmospheric δ13CCO2 values are then needed.” F. Engelbeen criticizing the Beck papers publishes data on "sea" delta 13C and comments like this: “That is a very fast one: from the base line in 1936 at around 330 ppmv (historical) to 430 ppmv in 1943.” on the latest Beck figure (2010) we have, however, (after smoothing filter), only circa 40 ppmv ... Let us dispense with, however, this "minor" inaccuracy. “Again, there is no sign of anything happening around 1943, even if the d13C records have a high resolution of 2-4 years around that period and the accuracy is fine enough to detect an extra addition/uptake of 1 GtC (0.5 ppmv) from/by vegetation or 4 GtC (2 ppmv) from the (deep) oceans. Thus all we can say is that other (proxy) methods, even with high resolution, don't show any abnormal variation around 1943.” Really, nothing unusual happens, the sharp in the 40's? Reconstruction of the history of anthropogenic CO 2 concentrations in the ocean. Khatiwala et al. 2009.: “Our results also suggest that the terrestrial biosphere was a source of CO 2 until the 1940s, subsequently turning into a sink.” ... and let's look at this graph: by “Global and European temperature (CSI 012) - Assessment published Jun 2010” Shocking, is not it (!?) Change (decrease) in temperature from 1940 to 1950 in Europe - comparable (increase) from 1950 to 2009! 10 years = 60 years! Rapid change in 1940-1950 can be found throughout NH - naturanych main source of CO2 emissions. ... And land d.13 C? Here, of course, I will quote my favorite graph: A bi-proxy reconstruction of Fontainebleau (France) growing season temperature from AD 1596 to 2000, Etien et al. 2008.: Fig. 2 - there is a “severe” proxy delta - δ13C - The data d. 13C for the period under discussion (194? -5?) are slightly lower than for the late twentieth century, their decline as rapidly as in Beck and temperatures in Europe ... Even the stomata do not want to show as beads and so wants to F. Engelbeen. In this figure (Kouwenberg, 2005.) but you can see a clear "hump" in the middle of the twentieth century. Also loving CO2 coccolith Phytoplankton Calcification in a High-CO2 World, Iglesias-Rodriguez et. al, 2008., indicate its mass, peak - fall - similar to that in Beck, but quite different in the case of d. 13C corals and sponges.
  48. Sea level rise: the broader picture
    Ken, I have a look at the tune you were playing (only glossed over it to be honest) & get back you later.
  49. The surprising result when you compare bad weather stations to good stations
    Actually Omnologos, the moment a skeptic starts using latin quotes, my spidey senses start going off. Well honed now. As for the conclusion of Menne et al, I too would have expected the opposite result i.e. poorly sited stations to be biased too warm. Perhaps the guidelines are unnecessarily too stringent?, maybe the people who laid down the guidelines over estimated the effects of possible biases?. In engineering for example, structures and buildings don't necessarily collapse because they don't meet a certain specification - normally because there's a large safety margin factored in to calculations. (Not that I'm suggesting shoddy work is good practice mind you) But that's for the scientists to examine.There's one conclusion I definitely would not draw - spurious warming. See graphic posted earlier.
  50. Arkadiusz Semczyszak at 22:08 PM on 1 September 2010
    Human CO2: Peddling Myths About The Carbon Cycle
    Sorry to burst formatting error, please discard my post
    Moderator Response: I think I fixed the formatting errors...

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