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Comments 111451 to 111500:

  1. Human CO2: Peddling Myths About The Carbon Cycle
    Another bug getting the upper hand - Coffee threatened by beetles in a warming world A tiny insect that thrives in warmer temperatures — the coffee berry borer — has been spreading steadily, devastating coffee plants in Africa, Latin America, and around the world http://www.guardian.co.uk/environment/2010/aug/27/coffee-threatened-beetles-warming
    Response: Global warming threatening my coffee? This time its personal!
  2. Why we can trust the surface temperature record
    Johnd, Your argument is false on its face. Why should I look up more data when you have not cited a single source for your extraordinary claim? You claim that spring is coming ealier AND fall is coming later due to seasons shifting. This is obviously impossible. It must be one or the other. Is spring coming earlier due to the supposed season shifting or fall later? What accounts for the shift in the other season, since both have been observed to change? In addition, the shift of spring and fall is 7-21 days in the last 30 years. You claim one day shift in 70 years. I suggest the scientists are right in saying there is not a shift in the seasons. Think about what you claim before you write it. The Milankovich cycles change where energy strikes Earth, not the season when it arrives. This is a completely unrelated topic from seasons shifting, you need to learn about the significance of the Milankovich cycles if you want to discuss them. Try Wikipedia for a start.
  3. Why we can trust the surface temperature record
    As per Steve O's list #11: You might add snow line elevation in mountains, ski resort seasonal duration, or even locations chosen for mounting on ski lifts.
  4. Can humans affect global climate?
    Why are we having such a long discussion about a SINGLE weather station. The reason deniers point to Armagh is that they claim the data from this station contradicts global warming. That is, by looking at only a single station for a limited number of years the warming doesn't look that bad. As Peter has shown above, this argument is completely false. The data from Armagh is completely consistent with global warming. Scientists EXPECT the trend at single stations to vary more than the global average. This is exactly what is observed. HR what is your point that you think is relevant about this single weather station?
  5. Human CO2: Peddling Myths About The Carbon Cycle
    jondoig: good call on the first point - I'll amend that straight away. On the second point, it's from Tripati 2009 (quoted from the intermediate version).
  6. Climate's changed before
    Svettypoo @119, I'll try again - Atmospheric CO2 concentrations during ancient greenhouse climates were similar to those predicted for A.D. 2100
  7. Ocean acidification threatens entire marine food chains
    I wish I had seen the first figure of 31 Dappledwater before posting my previous comment. That figure illustrates the point that the chemistry of the WML responds almost immediately to rising CO2.
  8. Ocean acidification threatens entire marine food chains
    The principal response to the "ocean water is well buffered" argument is to note the contrasting time scales of the processes involved, as noted in several comments above. The pH of surface ocean water (WML) responds to rising CO2 in the atmosphere almost immediately, within a year or so. By contrast, hundreds of years are required for acidified surface water to be mixed into the deep ocean, and it takes thousands of years for reactions with calcium carbonate in the deep sea to buffer the acid. These processes and their associated time scales are incorporated into models, and that is why scientists know that buffering reactions are "too little - too late". Organisms living in the WML will feel the full impacts of acidification over the next century or so, long before the acidified water even reaches most regions of the deep ocean where buffering reactions can occur.
  9. Ocean acidification threatens entire marine food chains
    Thingadonta @ 25 - Your latest speculative proposition has some problems. 1. The current rapid increase in atmospheric CO2, due to fossil fuel combustion, is being mirrored in CO2 dissolved in surface sea waters (those above 800 meters) & a corresponding decline in ocean ph. 2. This relationship between atmospheric CO2 and ocean ph dates back not only 800, 000 years ( See figure 1 of intermediate version here) , but likely many millions of years. 3. Note the scale of recent change (1800 to 2000) compared to changes in ocean ph for the last 20 odd million years. It's unmatched in the record because the natural processes (weathering & carbonate deposition) can't keep up with the rate humans are injecting carbon into the atmosphere. 4. There is no evidence of an unprecedented super-ginormous increase in volcanic activity on land, why do you suppose (sidestepping issues with ocean mixing, increased stratification and time lags) there is for submarine volcanoes?
  10. Why we can trust the surface temperature record
    You don't need thermometers to notice the temperature change was highlighted by a recent column I read by a vigneron in Victoria, Australia, who has records of when grapes were picked at his vineyard. These records went back many decades (being a family business) and he remarked that it was quite clear that over the past numerous decades the picking time has been advancing by a week each decade. The article was aptly titled "The proof is in the picking".
  11. Ocean acidification threatens entire marine food chains
    My previous link was broken, Ocean Acidification in Deep time
  12. Climate's changed before
    I do not have a loner perspective on solar evolution doug_bostrom and KR, just like you I think that the young dim sun hypothesis is likely true. To quote myself "Perhaps the dim sun hypothesis is correct and the sun has been warming,I believe this is probable" Please don't commit a straw man. I stated it wasn't empirical because there is no record of it, which is also true. Which one of my points do you disagree with? The only reason why I mentioned it was not empirically proven was because the OP claimed that CO2 effect on the climate can be proven empirically. KR, there is a statistical reason why i wanted to leave out the warming sun. Its the whole point of the argument. Here is the statistical explanation. Radiative forcing hypothesis claims CO2 combined with solar irridiance to provide the closest correlation with temperature proxies. statistically speaking, this would mean that both CO2 and solar irridiance should be positively correlated with temp proxies when calculated alone. I however agree 100% that solar irridiance is heavily correlated with temperature proxies. I wanted to show the lack of correlation that CO2 had with temperature proxies in paleoclimate. This makes perfect sense statistically and in the context of the argument. Please try and understand the argument and the post before making a rebuttal. KR, Sadly, those graphs that you posted do not show temperature on any axis. So I don't know how you can claim that "the evidence others have presented indicate that CO2 levels and solar forcing together match quite well to temperature." I am beginning to think that you post first and think later. Actually, simply by looking at the graph you can see the holes in the solar forcing combined with CO2 argument. The Ordovician, Devonian, early Carboniferous, and Permian ice ages are not correlated with troughs in the graph.(the Permian ice age happens on a mini crest, look closely) Thats 4 out of six ice ages... This blows a pretty gaping hole in the argument... Also, the interglacial between the 4th and 5th ice ages makes absolutely no sense at the level of radiative forcing at that moment.
  13. Can humans affect global climate?
    28.Peter Hogarth "The decadal average shows a very similar recent significant upwards trend in both records." Signficicant in relation to what? The 25year smoothing I did in comment #12 shows that the warming trend in the recent period is little different to other periods in the record. Such as the times around 1850 and 1950. Even your decadal smoothed data shows that to some extent. Yes the early data has to be qualified but it is all we have so have to either accept it or not. If you're going to make the statement that the recent period is in some way significant then you have to at least try to include as much of the record as possible to make that statement meaningful.
  14. Human CO2: Peddling Myths About The Carbon Cycle
    Also, where's the data behind "A natural change of 100ppm normally takes 5,000 to 20,000 years."? I ask because delayers like my local MP say we're just "accelerating" natural climate change. But by what factor? Joe Romm claimed 14,000 times, but that's compared to the trend over the last 600,000 years (22ppm), not to the maximum natural rate of change.
  15. Human CO2: Peddling Myths About The Carbon Cycle
    "Man-made CO2 in the atmosphere has increased by a third since the pre-industrial era" I think you mean "Man-made CO2 has increased the overall level of CO2 in the atmosphere by a third since the pre-industrial era".
  16. Ocean acidification threatens entire marine food chains
    johnd @27 Agreed John. I once had a sceptic show me an analysis he had done, looking at the change in energy distribution around the planet over the course of a year and ocean temperature changes over the same period as an argument for why the oceans don't have a big thermal lag. All he had actually done was make a rough calculation of the size of the WML. Somehow he just couldn't see that though...
  17. Climate's changed before
    Svettypoo I'm guessing you're pretty new to this topic, that or you're practicing some form of impressionism by ignoring important features of this topic. Notice that we've been adding C02 to the atmosphere in significant quantities only for the past 150 years, reaching close to 400ppm only in the past couple of decades. This means atmospheric temperature has not come close to equilibrating to the temperature it can be expected to reach at the present concentration, let alone where it'll eventually settle assuming we end up in the 800-1000ppm level where my intuition (cynicism?) suggests we'll sit given our indolence, complacency and proclivity to believe in comforting fairy tales. As to your loner perspective on solar evolution, yes I did read to the end of your version of "I doubt it" and found that part unpersuasive. Start here w/Spencer Weart's informative book on the topic of global warming to get caught up, if indeed you're fresh.
  18. What caused early 20th Century warming?
    muoncounter #35 I was rather looking forward to your reply to my post #36. It also is directly relevant to the latest topic concerning the surface temperature record.
  19. Comparing volcanic CO2 to human CO2
    I planted eight trees about 15 years ago. Only one of these is still alive. Meanwhile, two or three autochthonous species sprang up where nature dictated. The "CO2 problem" is the unnatural "population problem" that CO2 has amplified. Arguments based on per capita oil consumption are only part of the story. Its not an issue about energy or heat, as much as taking stock in what nature is able to deliver.
  20. Climate's changed before
    svettypoo - CO2 has, in the paleo record, been a component of climate change. In warming, as CO2 is forced out of warmer waters, it's been a positive feedback. When CO2 weathers into newly exposed rocks, dropping temperatures, it's been a forcing. Currently we're changing CO2 levels at 100x any paleo recorded rate. That makes CO2 the first to change, and thus it's the forcing on the climate. Doubling CO2 causes ~1°C, and with the various water vapor and other feedbacks, an estimated 3°C warming. As to solar activity - we have quite literally millions (billions?) of data points as to the evolution of stars of our sun's mass - via astronomy. Not to mention the various paleo proxies. We know that stars of our sun's type evolve warming over time. Unless you have solid evidence indicating basic astronomy and stellar lifetimes are wrong? As to your graph - You have quite clearly not incorporated the 'warming sun' into it. The evidence others have presented indicate that CO2 levels and solar forcing together match quite well to temperature.
  21. Climate's changed before
    Just so I'm clear on your position, svettypoo, what would you consider evidence of CO2 being the primary driver of the currently-occurring climate change? What would that evidence be? What would make you say, "Aha! Ok, I see it now"? Or do you think it's fundamentally impossible to provide, no matter what the conditions?
  22. Climate's changed before
    doug_bostrom, I hope you are not trying to argue paleoclimatic analysis with forest fire and beetle phenomena of the last several decades. I don't mean to be rude but please stay on topic. Secondly, I don't think you completed your thought in the third paragraph. You wrote "Levels of C02 unprecedented since ~15 million years ago when global temperatures were several degrees higher, is that the missing empirical evidence you're talking about, svettypoo?" I am going to assume you mean current levels of CO2 are unprecedented since ~15 mil years ago when global temperatures were several degrees higher. The logical question is if the CO2 is the major climate driver and ppm was matched 15 mil years ago and the average temp was several degrees warmer, why isn't it several degrees warmer now? I have not confirmed your statements anywhere but if they are true, they would only strengthen a AGW sceptic argument... I will give you a chance to explain what you meant with no judgement... I did form a conclusion. Did you not read my previous post? If I wasn't clear enough i will state it now. I concluded that CO2 has never been empirically shown with statistical significance to be the driver of climate and yet the IPCC models place it in that very position. I would also like to address my emphasis on empirical evidence. One can not claim to have a record of solar activity for the past 500 million years when such a record doesn't exist. If you would have kept on reading my post you would have read that even if we were to use the dim young sun hypothesized irridiation and combine it with the CO2 proxies as the major climate drivers we would not be able to explain prove causation of CO2 driven temperature. Lastly, I have tried to be as clear as possible in describing my argument and conclusion. Perhaps you could share some of your conclusions? Thanks.
  23. Why we can trust the surface temperature record
    You tell me, johnd. You're the person saying "I doubt it." Look up the publications of the researchers you're contradicting, find the errors and oversights you imply invalidate their conclusions, show by persuasion how your speculations about confounding factors are relevant.
  24. Why we can trust the surface temperature record
    michael sweet at 10:17 AM, if the solstices and equinoxes are not moving then that calls into question the existence of the related Milankovitch cycle. You appear to be claiming that it doesn't exist as I believe is commonly accepted, or else has stalled. What research is there to support such a claim?
  25. Why we can trust the surface temperature record
    doug_bostrom at 09:56 AM, which point are you referring to, clouds or the Milankovich axis wobble cycle?
  26. Comparing volcanic CO2 to human CO2
    TOP: According to NASA there are about 400 billion trees on the planet. If 7 billion of us each planted 5 trees per year, then over 12 years, we'd have doubled that figure. That's a lot of grazing land, crop land or desert to convert to forest in such a short time. And I wish that each of the trees I planted recently would grow to be a ton in ten years - and I live in a temperate rainforest climate zone. For now.
  27. Ocean acidification threatens entire marine food chains
    I see people are trying the "ocean water is well buffered" argument again. But wait a minute: we have managed to lower the pH _despite_ that buffering. What do you think that means will happen as we continue to pour yet MORE CO2 into the ocean? Soon, we will have only jellyfish to eat from the sea. Unless we wise up and do it FAST.
  28. Comparing volcanic CO2 to human CO2
    Great, TOP. How many trees have you planted? Your immediate family? Friends? Coworkers? Out of your first circle of acquainted men, women and children, how many or what fraction have planted 5 trees this year?
  29. Climate's changed before
    Beautiful blazing BC, burning bark and beetles. Today's climate sensitivity and models (at least issued by the IPCC) place an unprecedented emphasis on CO2, which simply isn't supported by the empirical record. Levels of C02 unprecedented since ~15 million years ago when global temperatures were several degrees higher, is that the missing empirical evidence you're talking about, svettypoo? I suppose we can dodge forming a conclusion by sticking with an appropriate definition of "empirical evidence."
  30. Comparing volcanic CO2 to human CO2
    If every man, woman and child on the planet plants 5 trees a year the fossil fuel CO2 problem is fixed. Consider that each tree grows to 1 ton in ten years.
  31. Why we can trust the surface temperature record
    johnd at 09:15 AM on 29 August, 2010 Flowers blooming earlier now than any time in the last 250 years The paper Climate Change and Cherry Tree Blossom Festivals in Japan shows how the date of flowering for some is now two or three weeks earlier than it was in their youth. From checking records going back to the 11th Century it states that "while temperatures have varied over this period, recent decades have been warmer on average than any time during the past 1000 years"
  32. Why we can trust the surface temperature record
    Johnd, Have you ever heard of leap years? Provide evidence of your extraordinary claim that the seasons are precessing as you claim. I note that summer solstice has not shifted, as it would with your claim. Please explain how the seasons could change but the solstice would not. Remember that these types of claim affect your reputation for reliability.
  33. Climate's changed before
    To Dappledwater: Sadly your link was broken and I couldn't open it. To quote you, "Furthermore, how exactly do you think the estimates for climate sensitivity came about, if not from the study of Earth's previous climates?" You try and mock me with this statement... but I couldn't agree with you more. I only wish estimates for climate sensitivity came from the Earth's previous climate. This however, isn't the case. Today's climate sensitivity and models (at least issued by the IPCC) place an unprecedented emphasis on CO2, which simply isn't supported by the empirical record.
  34. Climate's changed before
    I commented a little more than a week ago and I received some kind responses. Sorry I haven't answered yet, I've been camping in beautiful British Columbia with the family. The OP was nice enough to leave me a comment. I have to first respond that there are no records of solar activity that go back more than 1000 years (and even those are unreliable) There aren't even available proxies we can use to estimate solar activity. You must be refering to the young dim sun hypothesis... As explained earlier, this would make it impossible to find 3 degrees of warming through a doubling of CO2 "empirically." Proving something empirically means that you would have to prove it through records or experimentation. There is no empirical way to show any trends in the sun's history. Perhaps the dim sun hypothesis is correct and the sun has been warming (I believe this is probable although uncertain) even then CO2 doesn't tell doesn't even come close to telling the rest of the story. The solar irridiance has to make some pretty funky and unscientific loops to make CO2 be strongly correlated with temperature in the long term. Perhaps in the short term there is a strong correlation between CO2 and temp but I believe the 800 year lag weakens a CO2 - temp causation. I would like to know where you find estimates of detailed solar irridiance in the past. Furthermore I am even more curious of the methodology of how you combine these "guesstimates" with CO2 proxies to find a close correlation with temp. Lastly, I couldn't access your first link. I'm not sure if its broken or I am trying to open it wrongly. I am new to this site. Thank you
  35. Why we can trust the surface temperature record
    Johnd, your speculation, or can you provide cites of sufficient quantity and quality as to suggest the many researchers practicing in several domains you contradict are so incorrect as to warrant dismissing their collective evidence? I hear "I doubt it." Is that all?
  36. Why we can trust the surface temperature record
    johnd at 03:25 AM on 29 August, 2010 I suppose it depends which cloud cover dataset you use. The longer term surface observation dataset (SOBS) also shows a gradual increase in global mean cloud cover over a longer period than shown below. From the 2009 NOAA State of the Climate BAMS supplement.
  37. Why we can trust the surface temperature record
    Steve O at 08:45 AM, there are at least a couple of points that can probably be removed from your list, the most obvious being the changing times of the seasons, and the related blossoming of plants. The reasons for these can be found in the earth's axis precession of one cycle in 25800 years which equates to one complete day every 70 years. During the complete cycle the seasons will move completely through the calender in that time.
  38. Can humans affect global climate?
    All, I appreciate the Armagh stuff should be shifted to a more appropriate thread, but some of the points raised on this thread needed clarifying.
  39. Can humans affect global climate?
    HumanityRules at 14:20 PM on 27 August, 2010 and John Chapman at 15:03 PM on 27 August, 2010 “Why doesn't the Armagh Observatory have records since 2002?” The answer is not due to some hidden agenda as Peter B implies, but is far less exciting. The calibrated Armagh temperature data series to 2002 is from Butler 2005. This paper (submitted 2004) attempts to calibrate the record from the different thermometers and times of observation used in Armagh with data and information available up to the end of 2002. These factors are discussed in the paper, and have most importance for the data prior to the 20th century. An update (to 2004) is available in a more recent NASA study by Wilson 2006, which updates the calibrated records from 1844 to 2004, and of course Peter B correctly points out that up to date monthly records with daily resolution are available at the link he has kindly provided, but I believe this data is not yet in a convenient month by month tabular form. In the following charts I have used full up to date (to July 2010) Armagh monthly records and for comparison (and quick sanity check) the monthly (composite) CET (Central England Temperature) record, (details of CET calibration and error sources given in Parker 2005). Due to the close proximity of these sites, general short and long term correlation is high. The decadal average shows a very similar recent significant upwards trend in both records. This puts the chart in comment 17 (BP) in perspective. However there are some significant trend divergences from the Armagh data in the pre 20th Century period. It is in this period that there are higher uncertainties. In the 20th Century the 100yr trends are indistinguishable, which casts doubt on claims on some skeptical websites that "Urban Heat Island" (UHI) effects may have affected the Central England record. These same websites suggest Armagh is unaffected by UHI. Given the above, an eight year gap in the records (filled from Dublin data), and the discussion of uncertainties in the papers, we should be cautious about interpreting data from a single site from the very early instrumental period, though we are lucky to have these precious early instrumental records. Berényi Péter at 00:23 AM on 28 August, 2010 You state: “For the last 30 years it's +0.21°C/decade. However, for the last 20 years it is only 0.06°C/decade and for the last 80 it's 0.046” I am not sure how you have generated your values. Here are values I derived from the monthly data up to July 2010. Unless I am mistaken the 20 yr and 30 yr trends are not significantly different.
  40. Why we can trust the surface temperature record
    Also, if one wants to dispute the temperature record for whatever reason, then they also have to explain away: - changing timing of seasons - receding glaciers - rising sea levels - migration patterns of all sorts of creatures - declining sea ice - upward migration of mountain flora and fauna - increased range of tropical diseases - increased range of certain insects - timing of the icing over and thawing of rivers and lakes - blossoming of plants - and many, many more indicators, of which there are literally thousands of studies One does not need thermometers to ascertain increasing temperatures.
  41. Comparing volcanic CO2 to human CO2
    The second article TOP referred to can be downloaded here. The paper discusses how deglaciation can temporarily speed up the rates of volcanic activity, as a result of the reduced ice load on the volcano. The concluding sentences of the paper help put the magnitude of this effect into the perspective of modern, man-made changes in atmospheric CO2 concentrations. Finally, we estimate that volcanoes emit an excess 0.1 to 0.5 Gt of CO2 during deglaciation. Humans presently emit ~30 Gt of CO2 per year. If volcanic emissions influence the course of glacial/interglacial climates, it gives us pause that the accumulated volcanic CO2 emissions during ~10,000 years of deglaciation would, at current rates, be replicated by only a century of anthropogenic emissions.
  42. Ocean acidification threatens entire marine food chains
    Glenn Tamblyn at 19:12 PM, whilst your reference to the WML focused on CO2, the same conditions will also apply to any heat circulation relating to absorption and release as well as changes in volume due to temperature changes.
  43. CO2 was higher in the past
    Just reading through the posts and I noticed your comment. There were land based life forms during the Ordovician. Plant and animal life. I don't know where you heard that there weren't. There was a major extinction event but this just led to a reduction of biodiversity.
  44. Ocean acidification isn't serious
    @thingadonta: you seem to contradict yourself in your post. First, you write: "A recent paper which measured pH in the last 15 years in the north pacific shows it has experienced an average change of 0.03pH in the last 15 years. I'm not sure this is a rate to which there is concern." You then go on to write: "The geological record indicates that oceans appear to be strongly buffered, and do not change pH easily. They have apparently not changed pH more than 0.6 in the last 300 M years" Minus 0.003 pH per year would yield an decrease of 0.6 pH in a mere 300 years, not 300 million - to me, this rate of change really is matter for concern. Now, to be fair you didn't claim pH dropped by 0.6 over 300My, but rather that this was the extent of the variation (which in itself is meaningless when talking about the rate of change). Fortunately, we can take a look at the CO2 vs. pH graph above to have an idea of the rate at which acidification can take place outside of human intervention. Looking at the last drop of 0.2 in the pH, we can see it took place quite rapidly, but not any quicker than about 2,000 years (there is 20ky per tick on that graph). This is a rate of 0.0001 pH per year, or about 50x slower than the current decrease in pH. That figure is actually quite conservative, as research has shown the current acidification is occuring about 100x faster than what the geological record reveals. Your skepticism is natural, but in this case I think it's clear you're off-mark by two orders of magnitude...
  45. Why we can trust the surface temperature record
    Acushla at 20:06 PM, to dismiss the sun, one also has to dismiss variations in cloud cover. So did the long story short response include clouds as a factor and if so what changes in cloud cover was factored in to the nett result.
  46. Ocean acidification threatens entire marine food chains
    thingadonta @18: (Note: some NASA sceintists think the world's ocean water comes from comets-they know nothing about crustal geology and how granites expel water when they cool-which is how the world's oceans formed when the earths crust first cooled; the point is they are ignorant of what goes on in the subsurface. My guess is that they know more about it than you. I've known any number of geologists and geophysicists that worked for NASA--they're not all aeronautical engineers. Where do you think the water that granite expels when it cools comes from in the first place? The bulk of granite is emplaced above subduction zones where water-saturated sediments and rock are subducted and heated, resulting in partial melting in the upper mantle/lower crust. When those melts cool and crystallize (into granite), the water that facilitated the melting is released.
  47. Comparing volcanic CO2 to human CO2
    Cloarec, M.-F. L. and Marty, B. (1991), Volatile fluxes from volcanoes. Terra Nova, 3: 17–27. doi: 10.1111/j.1365-3121.1991.tb00839.x Feedback between deglaciation and volcanic emissions of CO2 harvard.edu [PDF]P Huybers, C Langmuir - … Letters, v286 (3-4), p479-491, 2009 - environment.harvard.edu EMEP/EEA air pollutant emission inventory guidebook 2009
    Moderator Response: Please pay attention to comments policy:

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  48. Why we can trust the surface temperature record
    I just finished reading an interesting book on the history of weather and climate data gathering, analysis and modeling; Paul Edwards - A Vast Machine. It's worth a read. He goes through a lot of the caveats and the intricacies of this type of historical trend analysis rife in complex systems science, where you have to go back and forth between historical data sets, adjust for calibration errors and biases in either direction, come up with ever more realistic ways to reconstruct a global dataset from local measurements, in a never ending process to continually improve your reconstruction of the climate record. He focuses a great deal on the interplay between models of various sorts and what we refer to as "the data", and notes that in this type of science there is no such thing as data without models. You constantly have to model things like the changes in measurement devices, adjustments for the UHI effect, interpolate between stations, and so on. There's simply no such thing as meaningful raw data. He points out that the UAH controversy was framed in this mistaken notion that satellites provide "measurements" of global temperatures whereas the surface record is based on such model adjustments, when in reality the satellite data contains some of the most complex modeling work of all. Anyway, bookplug!
  49. Why we can trust the surface temperature record
    Kelly O'Day writes: I maintain a csv file of monthly temperature anomalies for the 5 major global temperature series that you can download and analyze in Excel, R or other software. For those who haven't visited Kelly's website, there are all kinds of useful and informative tools and graphics there.
  50. Arctic sea ice... take 2
    I agree that it is important to understand the strengths and limitations of whatever data set you are using. And any of the measures has the potential to mislead if the limitations are not understood. The issues in measuring area in times of surface melt are also strengths: if the area of surface melt is increasing, that tells you something. And melt ponds have a lower albedo than snow covered ice, so they are contributing to the feedback effect in the same way (if to a lesser extent) than open water. But extent doesn't account for open water until it reaches 85%, so it underestimates this effect. And since ice tends to spread out across the surface of water, extent is likely concealing the the degree to which the ice is depleted as solid ice thins and breaks up. But, as you say, any way you slice it, all three measures are in decline and this year will be no exception. Area and extent are headed for the second or third lowest of all time, and volume will almost certainly be the lowest ever.

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