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Comments 125351 to 125400:

  1. On the reliability of the U.S. Surface Temperature Record
    Oh dear, poor deniers. Another of their imaginary supportive planks falls away beneath them...
  2. IPCC is alarmist
    While I understand the two first pictures, I dont get the last one (figure 4) to make sense. The observed trend starts to diverge from the IPCC models mean at latest in the end of the 1970's - so what were those models based on, pre-1980 data?
  3. Skeptical Science now an iPhone app
    But the fall and rise after volcanos is concomitant with the fall and rise in radiative forcing even though the delta T spike is smaller. A lag would suggest at the very least a slower recovery in delta T. Another example is the period 1910-1940. A relatively modest increase in radiative forcing (compared with present times) yet no apparent lag. In fact the rise of ~0.5oC in delta T occurs alongside the smooth rise (no volcano's) in radiative forcing. 1910-1940 RF increase ~0.5, delta T 0.5oC 1980-2003 RF increase ~2, delta T 0.6-0.7oC The numbers don't seem to add up.
  4. On the reliability of the U.S. Surface Temperature Record
    Oh dear, Watts will not be a happy camper. I wonder how long until we see this as a headline on WUWT? I'm not holding my breath. Point is, after reading about a dozen different articles on the issue, I've known all along that the so-called Urban Heat Island effect was nothing more than an Urban Legend!
  5. The IPCC's 2035 prediction about Himalayan glaciers
    Charlie A, it's a typo, the starting year is 1947 not 1847.
  6. The chaos of confusing the concepts
    Berényi Péter writes: "This is not so. Weather/climate is chaotic on all time scales." Hmmmm. Are you suggesting we can't make long-term predictions of trends in temperature, precipitation, etc.? Because where I am now (New England, USA) it's currently -16 C. I am highly confident that six months from now, the outside temperature will be in the +20 to +30 C range here. I can make that prediction confidently because although the day-to-day weather is chaotic and unpredictable, there is a physical process ("the seasons") superimposed on that short-term variability. Likewise, with climate change, we know that increasing CO2, CH4, N2O, CFCs, etc. in the atmosphere will superimpose a warming trend on the global climate. We can't predict the details of the weather on a specific date in 2050 (any more than we can predict them for a given day in New England this summer), but we can predict that on average the climate will be warmer.
  7. The chaos of confusing the concepts
    I'm not sure if it applies, but I thought of one analogy reflecting the phenomenon that climate on its scale is more predictable than weather. Consider the position at time 0 of a specific N2 molecule in a closed room filled with air, vs the temperature at time 0 in the same room. After one hour, it would be much easier to predict the temperature in the room than it would be to predict the position of the molecule. I assume that from a physics point of view one could argue that the two phenomena described is essentially the same, but on different scales, which you may also say about weather and climate. However my academic background is far from both physics and meterology so I'm not sure that my analogy is a particularily good one.
  8. Berényi Péter at 20:48 PM on 22 January 2010
    The chaos of confusing the concepts
    This is not so. Weather/climate is chaotic on all time scales. Chaotic climate response to long-term solar forcing variability A. Bershadskii 2009 EPL 88 60004 (5pp) doi: 10.1209/0295-5075/88/60004 http://www.iop.org/EJ/abstract/0295-5075/88/6/60004 A slightly earlier (6 Jul 2009 19:10:25 GMT) version of the same paper can be found at arXiv.org http://arxiv.org/abs/0903.2795
  9. The IPCC's 2035 prediction about Himalayan glaciers
    Perhaps someone can explain something else in Section 10.6.2: The Himalayan glaciers of the IPCC Fourth Assessment Report: How is the second line of table 10.9 calculated? http://www.ipcc.ch/publications_and_data/ar4/wg2/en/ch10s10-6-2.html Pindari Glacier; 2840 meters of retreat from 1845 to 1966; average retreat 135.2 meters/year. I calculate an average 23.5 meters per year, which more closely matches some other reports of 27 meters/year from 1847 to 1906, slowing to 20 meters per year from 1906 to 1958; with a further slowing to about 10 meters per year since 1966. My e-mails to IPCC go unanswered. Perhaps other readers of this blog can explain the 135.2 meter/year average retreat number for Pindari Glacier.
  10. The chaos of confusing the concepts
    Amazing post!! I remember reading about this in the book "Chaos" by James Gleick years ago and playing around myself with the bundled software doing fractals and strange attractors. You can download the shareware version of it here and source code too. http://www.cs.sjsu.edu/~rucker/chaos.htm From memory...I also remember reading that Lorentz discovered it by accident (like all great science) when he was in a rush or there was a power cut and he had to start his weather model with less decimal points in it and was very surprised by the print out the next day.
  11. Skeptical Science now an iPhone app
    A slight of hand appears to occur in the Hansen paper. Total net forcing 1880-2003 = 1.85Wm-1 delta T 1880-2003 = 0.6oC but 1Wm-1 should give delta T of 0.6oC so where is the delta T from the remain 0.85wm-1 of net radiative forcing? Oh yeah it's "in the pipeline". Three words can dismiss the fact that close to half the delta T is so far unaccounted for. I guess there is a suggestion of a lag here but no attempt to justify it. In fact when you look at the cooling caused by volcano's and the subsequent recovery after aerosols are removed there appears to be no lag in delta T to radiative forcing.
    Response: Actually, volcanic eruptions are a good example of climate lag and how "warming in the pipeline" works. Note the comparison between radiative forcing and global temperature over the 20th Century:



    The big downward spikes in net forcing are due to volcanic eruptions. Why doesn't temperature fall the same amount? Because of the great thermal inertia of the oceans. What happens is a volcano erupts, throwing up sulfate aerosols into the atmosphere. This immediately creates an energy imbalance - suddenly less sunlight is getting in. So the planet starts to cool.

    Note - the atmosphere responds relatively quickly. But it takes time for the oceans to cool - this is what you would call "cooling in the pipeline". However, and fortunately for us, the aerosols wash out of the atmosphere within a few years and the energy imbalance bounces back to what it was before. But if for some reason, the aerosols stayed in the atmosphere, what we would observe is the planet cooling over a few decades until the climate reached equilbrium.
  12. The chaos of confusing the concepts
    Excellent post! Thanks!
  13. Jacob Bock Axelsen at 11:22 AM on 22 January 2010
    The chaos of confusing the concepts
    @Riccardo Thanks for your positive comment. The picture is just artwork - or an example, as you put it. The weather attractor would be huge on this scale, so I scaled it down to match the fluctuations instead. I hope you still like it.
  14. Could CFCs be causing global warming?
    I currently am not able to access my institution's library, so I can't go through the paywall to read Lu's paper. I'm curious though to know exactly what technique he employed that permitted him to establish that "correlation between global temperature and CFCs is evidence that CFCs have been the dominant driver of climate over the past century". When I look at the first graph, I see a 20th century warming trend that commences before the increase in EESC, and I see a period of (aerosol attributed) cooling kicking in at the time that EESC does begin to rise. This would seem to indicate that for a decade or so either side of the point where EESC begins to increase, there is no relationship with temperature at all. Any 'correlation' seems to occur after 1960, or even later, and given the vast number of human-produced substances that would demonstrate a similar trend, I would suggest that the correlation is a completely spurious one. At first blush, and given the poor relationship implied by the graph, it's certainly no evidence of a (partial, at best) correlation indicating causation. If this truly is Lu's claim, it should have been weeded out during review.
  15. The IPCC's 2035 prediction about Himalayan glaciers
    I am a touch puzzled by the confident assertion that warming may equal increased precipiation which may equal in some cases increased glacier growth. I seem to recall that precipitation may cause at least local warming as water vapor when it turns to liquid water or ice releases latent thermal energy. I'm happy to be subject to correction on this score. Anyway, I will check out the suggested online sources with interest.
  16. The chaos of confusing the concepts
    That's a good question, Riccardo. At first, I thought it was just an illustrative example, but a growth in the Lorenz attractor might represent larger chaotic variation in weather (i.e. more weather extremes). Obviously, whether this occurs or not is an important question when discussing the effects of long-term shifts in climate averages.
  17. The chaos of confusing the concepts
    Excellent. Clear, concise and easy enough for averyone to understand. One question, the growth of the Lorenz attractor in the last picture is an observed feature or is just an example?
  18. The chaos of confusing the concepts
    Dr. Spencer Weart's "The Discovery of Global Warming" has a truly excellent chapter devoted to the foundations and evolution of climate modeling, particularly general circulation models: http://www.aip.org/history/climate/GCM.htm Note to doubters, skeptics, etc: Even if you're not prepared to join the mainstream, Weart's book covers this topic warts and all. If you're looking for weaknesses, you need to read it. Don't take on faith what you can pull from a primary source.
  19. The IPCC's 2035 prediction about Himalayan glaciers
    WeatherRusty at 01:53 AM on 22 January, 2010 Alexandre, You may be interested in this online "textbook" which provides a very good synoptic overview of climate science. It covers most areas of interest in a factual, unbiased way. Also be sure to view Weart's book, also online: http://www.aip.org/history
  20. The IPCC's 2035 prediction about Himalayan glaciers
    Yesterday, the IPCC released an apology and reaffirmed that the conclusions reported in the Synthesis Report are robust:
    Climate change is expected to exacerbate current stresses on water resources from population growth and economic and land-use change, including urbanisation. On a regional scale, mountain snow pack, glaciers and small ice caps play a crucial role in freshwater availability. Widespread mass losses from glaciers and reductions in snow cover over recent decades are projected to accelerate throughout the 21st century, reducing water availability, hydropower potential, and changing seasonality of flows in regions supplied by meltwater from major mountain ranges (e.g. Hindu-Kush, Himalaya, Andes), where more than one-sixth of the world population currently lives. This conclusion is robust, appropriate, and entirely consistent with the underlying science and the broader IPCC assessment.
    *I find the apology a bit indulgent anyway, and I hope that they add a corrigendum to the text soon.
  21. Berényi Péter at 06:02 AM on 22 January 2010
    The IPCC's 2035 prediction about Himalayan glaciers
    IPCC still has it on its website with no footnote, comment or whatever. IPCC Fourth Assessment Report: Climate Change 2007 Climate Change 2007: Working Group II: Impacts, Adaption and Vulnerability 10.6.2 The Himalayan glaciers http://www.ipcc.ch/publications_and_data/ar4/wg2/en/ch10s10-6-2.html
  22. Skeptical Science now an iPhone app
    Are they so different, HR? The Hansen et al analysis (see pdf in my post #15; it's the same data that John uses in his response in post #8) gives a solar contribution that is around 8% of the greenhouse forcing. Damon's 1999 analysis yields 15% (contribution of solar cycle length to total warming) through the 20th century (up to 1997). These values are not that different, and a number of analyses using up to date estimation of the change of solar irradiance, puts the solar contribution around 10%...these all seem to be reasonably self-consistent. One has to be careful with Damon's analysis. He wasn't particularly determining the solar contribution to warming. He was really addressing an analysis of Friis-Christensen and Lassen which purported to show that apparent correlations between solar cycle length and climate indicated that the solar contribution was 100%. Damon was pointing out that the F-C/L analysis wasn't done correctly and if it were, the solar cycle contribution would be 15% through 1997. However there isn't much evidence I think that the solar cycle length is a very good proxy for solar output, and there isn't a good theoretical basis for this relationship; far better to use a well-characterized analysis of solar irradiance, either by direct measurement, or by analysis of the solar cycle/sunspot measure for periods before direct monitoring of irradiance.
  23. The IPCC's 2035 prediction about Himalayan glaciers
    #11 danielbacon, I'm not 100% sure, but it seems to have been Prof Graham Cogley (Trent University, Ontario), who has also sent a letter (with Kargel, Kaser and Van derVeen) to Science. The first public comment seems to be the one by Madhav L. Khandekar (introduced as "research scientist from Environment Canada and is an expert reviewer for the IPCC 2007 Climate Change Documents") in a guest post on Roger Pielke Sr.'s blog on December 1st. But he credits the relevant statement to Graham Cogley.
  24. The hockey stick divergence problem
    He, Michael Mann says there is no divergence problem: http://www.realclimate.org/index.php/archives/2007/05/the-weirdest-millennium/#comment-34017
  25. The hockey stick divergence problem
    @lord_sidcup: No, quite the opposite. McIntyre was aware of the divergence problem. Actually he has a commented on ipcc 2007: "Show the Briffa et al reconstruction through to its end; don’t stop in 1960. Then comment and deal with the “divergence problem” if you need to. Don’t cover up the divergence by truncating this graphic. This was done in IPCC TAR; this was misleading. (Reviewer’s comment ID #: 309-18)" It was rejected: "Rejected – though note ‘divergence’ issue will be discussed, still considered inappropriate to show recent section of Briffa et al. series." Can anyone explain me, why it is 'still considered inappropriate ' to show a graphic in a honest way?
  26. Skeptical Science now an iPhone app
    Just to add more to your list Chris. From the diagram posted by John in response to post #8, GISS seem to give solar almost 0 net change in radiative forcing over the whole of the century. Suggesting solar has had almost no net effect on global warming for the whole of the 20th century. John's Damon 1999 paper suggest 25% in 1980 and 15% in 1997. These are surely mutually exclusive.
  27. The IPCC's 2035 prediction about Himalayan glaciers
    Alexandre, You may be interested in this online "textbook" which provides a very good synoptic overview of climate science. It covers most areas of interest in a factual, unbiased way. SEE: http://stratus.astr.ucl.ac.be/textbook/index.html
  28. The IPCC's 2035 prediction about Himalayan glaciers
    "The mistakes were found not by skeptics like Michaels, but by a few of the scientists themselves, including one who is an IPCC co-author." http://news.yahoo.com/s/ap/20100121/ap_on_sc/sci_un_climate_change... So any one know who found it and when?
  29. 2009 - 2nd hottest year on record while sun is coolest in a century
    John I've been working on showing current TSI data. I have added a widget to my blog to show NASA's SORCE TSI data. University of Colorado - Bolder posts the data about 1 week after readings. Here's a link to my most recent TSI image, using SORCE daily readings
    Response: Thanks Kelly, that's a great resource. It's interesting to see the upturn of TSI in recent months as the next solar cycle begins - the PMOD TSI data stops halfway through 2009 so its good to have more recent data.
  30. Skeptical Science now an iPhone app
    re #12,13 Yes, the solar scientists that analyze solar output in detail have determined that solar contributions to 20th century warming are rather small overall. Several recent analyses indicate a solar contribution to total 20th century warming of the order of 10%, with none of this in the period of late 20th century and contemporary warming [*]. So solar contributions made a small contribution to early-mid 20th century warming. A significant proportion of the warming in the period to the mid 20th century warming was likely the recovery from very high volcanic activity in the late 19th, early 20th century [*;** ; ***]. There was obviously a contribution from anthropogenic greenhouse gases [*; **; ***; ****], and perhaps a small contribution from ocean circulation effects [****]. Obviously the attribution of 20th century warming requires an assessment and incorporation of all of these contributions as is done in the papers below marked [*] and [***]. [*] C. M. Ammann et al. (2007) Solar influence on climate during the past millennium: Results from transient simulations with the NCAR Climate System Model Proc. Natl. Acad. Sci. USA 104, 3713-3718 http://www.pnas.org/content/104/10/3713.abstract Lean, J. L., and D. H. Rind (2008), How natural and anthropogenic influences alter global and regional surface temperatures: 1889 to 2006 Geophys. Res. Lett., 35, L18701 http://www.atmosp.physics.utoronto.ca/~jclub/journalclub_files/LeanGRL2008.pdf R.E. Benestad and G. A. Schmidt (2009) Solar trends and global warming J. Geophys. Res. 114, D14101 http://europa.agu.org:8005/?view=article&uri=/journals/jd/jd0914/2008JD011639/2008JD011639.xml&t=2009,Benestad [**] Mann M.E. (2007) Climate over the past two millennia Annu. Rev. Earth Planet. Sci. 35, 111-136 http://arjournals.annualreviews.org/doi/abs/10.1146/annurev.earth.35.031306.140042 [***] Hansen, J. et al. (2005) Earth’s Energy Imbalance: Confirmation and Implications Science 308, 1431-1435 http://pubs.giss.nasa.gov/docs/2005/2005_Hansen_etal_1.pdf [****] Swanson K.L. et. al. (2009) Long-term natural variability and 20th century climate change Proc. Natl. Acad. Sci. USA 106, 16120-16123 http://www.pnas.org/content/106/38/16120.abstract?sid=a5bc499d-5e20-48cc-97ae-8e54afbebb8e
  31. Skeptical Science now an iPhone app
    "Response: When the sun is showing a long term warming trend, the solar cycle tends to get faster. Conversely, when the sun is cooling, the solar cycle slows. This is why the solar cycle 24 is taking so long to get started at the moment - because the sun is cooling at the moment. Why this is so, I leave as an exercise for the reader :-)" Isn't wrong to describe the sun as cooling or warming? We are surely dealing with surface immittance and not total energy content by unit.
  32. Berényi Péter at 00:43 AM on 22 January 2010
    Skeptical Science now an iPhone app
    Riccardo, working on a problem for decades is not the same as getting the easy (and most important) part of the job done ASAP. I am not even talking about a full scale reanalysis as it is undersood in "climate science" circles (the one involving extensive statistical data kneading), but straightforward correction for known and deterministic instrumental biases. I am not implying it would be a low budget operation. But it is easy indeed as a scientific endeavor. One does not have to bother with hypothetic climate/atmospheric models and the like, just simple instruments and raw data. Proper collection of metadata, reconstruction of devices and testing their response to varying pressure, temperature, moisture and radiation histories costs money, but does not require much ingenuity. Just plain old honest work. I am surprised beyond imagination that this issue is not pushed much more forcefully. In fact it seems no one has got grant money to do it. Of course there is a danger the results could turn out "supporting lower climate sensitivity than the standard IPCC range". Come to think of it, could be rather difficult to get a grant for this purpose with opinionated referees around. Considering it is THE experimentum crucis for the present climate modelling paradigm, everyone involved should welcome such an opportunity, not suppress it. Just imagine Albert Einstein trying to prevent Sir Arthur Stanley Eddington to get to Príncipe in time to capture full eclipse by "saying people are working on eclipses for millenia, so why the rush". No one doubts the lower troposphere is getting wetter nor older instruments tending to have a longer relaxation time at low temperatures. But I would not bet on correcting for relaxation time bias could charm away the decreasing specific humidity trend measured by radiosondes up there, for this trend is also observable at the 700 hPa level, where all instruments behave reasonably well, even the ancient ones. Also, the ongoing loss of high altitude glacier mass is more consistent with decreasing relative humidity at that level than with a constant one.
  33. Skeptical Science now an iPhone app
    Yet the radiative forcing graph in your response to post #8 would suggest that GISS think solar has remained almost unchanged in it effect for the whole of the century. All the quote from the paapers you mention, including Lassen 1999, suggest solar can only be ruled out for the most recent warming period.
  34. The IPCC's 2035 prediction about Himalayan glaciers
    Thanks for the great post, John. The paragraph with the moral of this story summarizes well my own view, too. I'd like to place a suggestion. It's off-topic, but I don't know where else I should send it. I know a few good websites (like this one) dedicated to debunk "skeptical" claims. I've been questioning this approach, though. I think it is much more compelling and instructive to explain the existing science behind AGW then to respond to denialist (mostly) nonsense. People can learn, then, how robust the mainstream consensus is and THEN compare it with the feeble contrarian reasoning. I find it much more constructive. Would it be feasible/interesting to add a section like this here? Could anyone point me a website with this approach?
  35. Skeptical Science now an iPhone app
    Given the good correlation upto 1975 do we conclude that solar was the dominant factor controlling change in global temp for the first 3/4 of the century?
  36. The IPCC's 2035 prediction about Himalayan glaciers
    re #7 sweart, I think you're being unfair on Barnett et al. (2005). If you read their section on Himalaya-Hindu-Kush, which they address as a whole region, they makesome rather uncontroversial statements that are referenced by 5 citations, one of which is the report of the China Glacier Inventory. They state:
    There is little doubt that the glaciers of the HKH region are melting and that the melting is accompanied by a long-term increase of near-surface air temperature (ref. 44 and Figs 2.9 and 2.10 in ref. 1), the same level of warming we saw impacting the western USA. After 25 years of study, the China Glacier Inventory was recently released45. It showed substantial melting of virtually all glaciers, with one of the most marked retreats in the last 13 years (750 m) of the glacier that acts as one of the major sources of the Yangtze River, the largest river in China. In total, it is estimated that the entire HKH ice mass has decreased in the last two decades. Furthermore, the rate of melting seems to be accelerating46. The few analytical studies that exist for the region suggest both a regression of the maximum spring stream-flow period in the annual cycle by about 30 days (ref. 47) and an increase in glacier melt runoff by 33–38% (ref. 48). These numbers seem consistent with what is being observed and bear striking similarities to the stream-flow results from the western USA. The huge inconsistency, however, occurs in the impacts on local water supplies. In the western USA, model-predicted impacts are already being seen in the hydrological cycle. The models suggest that the impacts will appear as a long-term trend in snow amount and runoff. But in the HKH region, there may (for the next several decades) appear to be normal, even increased, amounts of available melt water to satisfy dry season needs. The shortage, when it comes, will likely arrive much more abruptly in time; with water systems going from plenty to want in perhaps a few decades or less.
    So the Chinese studies certainly don't address "one ice mass"...moreover the authors are quite clear that the IPCC citation refers specifically to air temerature (see reproduced text above). Barnett et al (2005) also cite studies for this region that address the strength of glacier-fed stream flow and glacier melt run-off. Reading this section, and in the context of the whole article, doesn't suggest that there's anything wrong with the article, certainly not to the extent that one would question the peer-review process. Total Himalayan glacier mass balance is negative[*], and that's what Barnett et al (2005) state, and discuss implications thereof. [*] http://web.hwr.arizona.edu/~gleonard/2009Dec-FallAGU-Soot-PressConference-Backgrounder-Kargel.pdf
  37. There is no consensus
    Tom, I dismiss all skeptic work, as does anyone who understands how science works. What an irony that you are worried about people being sceptic but in the same time defend someone whose ideas neglect the validity of science in general.
  38. Berényi Péter at 22:48 PM on 21 January 2010
    The IPCC's 2035 prediction about Himalayan glaciers
    The Himalayan glacier issue is a complex one. MoEF Discussion Paper Himalayan Glaciers A State-of-Art Review of Glacial Studies, Glacial Retreat and Climate Change - V.K.Raina, Ex. Deputy Director General, Geological Survey of India http://gbpihed.gov.in/MoEF%20Dissussion%20Paper%20on%20Himalayan%20Glaciers.pdf Also, the constant mid & upper tropospheric relative humidity hypotheses is not supported by (sub)tropical glacier shrinkage. Especially during the sixties and seventies, when temperature decreased, but glacier mass loss only slowed down, not reversed. On the other hand, if air above 1500-2000 m is getting ever drier as CO2 goes up, glaciers should shrink. It is even more pronounced on Kilimanjaro, Africa, where sublimation is the dominant ice loss process.
  39. The IPCC's 2035 prediction about Himalayan glaciers
    Supporters of the IPCC should be first to note that a similar error is found elsewhere in the Working Group 2 report, in chapter 3. In section 3.4.3 we read that “the entire Hindu Kush-Himalaya ice mass has decreased in the last two decades.” The citation is to Barnett et al. (2005), a Nature paper that does indeed say the Himalaya-Hindu Kush area was losing ice. So far so good. But the refereeing there failed, for Barnett et al. cite only two sources for their confident statement: a Chinese paper that, judging from the title (I haven’t tried to find the whole text), actually studied only one ice mass... and figures in the IPCC 2001 report, which turn out to show only temperature rise over the Himalayas, not actual glacier retreat. In short, the scientific communities involved had really poor quality-control in this case, not just at the IPCC level but in the Nature article refereeing. Oh well, historians of science know that it is a rare scientific paper that does NOT contain an error; that's the inevitable result of working at the frontier of knowledge. Himalayan glaciers depend crucially on the notoriously fickle monsoon, and glaciers in general depend as much on precipitation as temperature (like many tree rings!). The Physical Sciences panel was rightly concerned above all with ice mass, a lot of which is in ice caps rather than glaciers. The crucial data for the Panel I report are to be found at http://instaar.colorado.edu/other/download/OP58_dyurgerov_meier.pdf with a broader overview at http://www.hydro.washington.edu/.../kaser_et_al_grl_2006.pdf (I guess published too late to be included in the IPCC reference list, but they do show the figures.)
  40. Two attempts to blame global warming on volcanoes
    From Peru. Just a possibility, but could this maybe be the result of a lack of data from the USSR during at least some of this period? I'm not saying this is the case, merely hypothesizing.
  41. The IPCC's 2035 prediction about Himalayan glaciers
    #3 Chriscanaris - "I have come across reports that some glaciers may be growing ... If so, what's the overall significance?" John has answered this in terms of proportions. Something worth adding is that because glacier size is determined (simplistically) by the balance between snow arriving at the top end, and ice melting at the bottom end, they will react to global warming in ways depending on their geographic situation. In most cases (over 90%) the equation is simply that global warming brings more melting and less snow. In a small minority of cases, especially those in coastal regions, although the bottom is melting faster, the warmer sea also results in more snowfall at the top. If the latter factor outweighs the former, the glacier can actually grow. It is not clear to me whether this is a temporary effect, and that temps continuing to rise will shrink these glaciers too, or whether snowfall can continue to increase proportionately. My gut feeling is that the increase in snow is likely to be a short term phenomenon, which seems to be suggested by the falling proportion of glaciers that are growing.
  42. The IPCC's 2035 prediction about Himalayan glaciers
    The link to the Kotlyakov report is now broken, you can find it here (p. 66).
  43. The IPCC's 2035 prediction about Himalayan glaciers
    Thanks for the summary, John. I really like that you cover the current affairs. Although the reference was the WWF 2005 report, it seems that the IPCC text was more likely paraphrased from an article published in the India Environement Portal in 1999:
    "Glaciers in the Himalaya are receding faster than in any other part of the world and, if the present rate continues, the likelihood of them disappearing by the year 2035 is very high," says the International Commission for Snow and Ice (ICSI) in its recent study on Asian glaciers. "But if the Earth keeps getting warmer at the current rate, it might happen much sooner," says Syed Iqbal Hasnain of the School of Environmental Sciences, Jawaharlal Nehru University, New Delhi. Hasnain is also the chairperson of the Working Group on Himalayan Glaciology (WGHG), constituted in 1995 by the ICSI. "The glacier will be decaying at rapid, catastrophic rates. Its total area will shrink from the present 500,000 to 100,000 square km by the year 2035," says former ICSI president V M Kotlyakov in the report "Variations of snow and ice in the past and present on a global and regional scale".
    As Deltoid mentions, John Nielsen-Gammon has a grood article on the original sources, including the Kotlyakov report, where the year 2035 may come from as a misreading of 2350 (here and here) As for the real consensus on the Hymalayan glaciers, the link provided by RealClimate to Karger et al at the AGU press conference last December is very good (see slides 13 and 40-41).
  44. Skeptical Science now an iPhone app
    Berényi Péter, the intercomparison between the various reanalisys in Trenberth et al. shows which is more reliable; Paltridge et al. failed to notice it. But the point is not even this. It is that due the unreliability of radiosonde data no strong conclusions can be draw, as you (not Paltridge) are trying to do. You surely read what Paltridge wrote on Climate Audit; there was no political bias to force him to state that radiosonde data are not reliable, but he confirmed. This leaves no room to your (arbitrary) hypothesis that he was forced to write so to pass a biased peer review. Your idea on how reanalysis work is really trivial. You are assuming that we now know for all the stations, all the flights, all the instruments and all the sensors the influences of an uncontrolled ambient on the measurements, which is clearly not true. It should not be so hard to see given that we have several different and contrasting reanalysis and people working on it for decades. Were it so simple as you say anyone could have done it.
  45. 2009 - 2nd hottest year on record while sun is coolest in a century
    Humanity Rules, yes, we are looking a temperature and ENSO do have an effect. But given that no energy is produced it can just cause fluctuations, not trends. I already explained why i took just part of the time range available. From around the '70s the contribution of GHG to warming has been strong enough to be clearly identified and the sun forcing has been roughly constant. If you want to reproduce the whole instrumental record from 1880, you need to put together all the contributions to forcing.
  46. The IPCC's 2035 prediction about Himalayan glaciers
    I have come across reports that some glaciers may be growing (alas I do not have sources to hand). If so, what's the overall significance?
    Response: Some glaciers are growing. In fact, the IPCC mentions them in their section on glaciers - including a Himalayan glacier in the Karakoram mountains. However, these are isolated cases - the vast majority of glaciers are shrinking and the shrinking trend is increasing. According to the World Glacier Monitoring Service, 77% of monitored glaciers were retreating in 2002. This was followed by 94% of monitored glaciers retreating in 2003. The global trend is accelerating shrinkage:


    Cumulative mass balance curves for the mean of all glaciers and 30 'reference' glaciers (WGMS 2008).
  47. The IPCC's 2035 prediction about Himalayan glaciers
    Yes, this has all been as much, if not more, of a beat up than the "hide the decline" nonsense. But the two together clearly signal a new determination by the denier, and those behind them, to stop at nothing in order that the world will stop at nothing. I saw one comment to the effect that if the glaciers were going to melt in 25 years that would be a cause for concern but 340 years, who cares. The idea that glaciers are already retreating, all over the world, and that they are acting as one of the canaries in the coalmine escapes these people (and the mass media, including people like the Guardian, and the ABC, who should know better). Similarly the idea that whether it is 35 or 350, the processes are now in place for yet another unthinkable thing to happen, inevitably, has also escaped the deniers. And the obvious point that since the glaciers are already in retreat, the effects of this are already underway. I think there is plenty of room for debate on all kinds of timing issues (sea level rise and acidification, desertification, increasing storm frequency, ice free Arctic, loss of Greenland ice cap and so on). They are of some practical import, but really the exact speed is a matter of mainly academic interest. If you are stalled on a level crossing, the approaching train could be coming at any speed really. but getting off is the important thing. In fact an emphasis on the speed at which things are happening lets politicians off the hook - plenty of time to deal (or have someone else deal) with that, they think. The important message though, is that these effects are now built into the atmosphere, and it is going to take a long time to turn them around.
  48. Two attempts to blame global warming on volcanoes
    It is an interesting possibility, but this graph: http://data.giss.nasa.gov/gistemp/graphs/Fig.A4.lrg.gif Shows that the discrepancy is GREATER IN LAND than in the Global Oceans. Whatever the cause is, this strange behaviour ONLY occurs in NORTHEN LATITUDES(23,6ºN-90ºN): http://data.giss.nasa.gov/gistemp/graphs/Fig.A3.lrg.gif http://data.giss.nasa.gov/gistemp/graphs/Fig.B.lrg.gif
  49. The IPCC's 2035 prediction about Himalayan glaciers
    The glaciers are retreating and there will be significant consequences long before they are all gone. Deltoid has an interesting study on how the error occurred. The trouble with peer reviewed is that it is usually behind a pay-wall and I am not paying to read an article that I probably will not understand. I am also learning there is peer review and then peer review, some peer reviewed journals have a much higher standing than others. What I have learned from the peer reviewed articles is that there is still a high degree of uncertainty on how glaciers will react. Melt they will but how fast and what mechanisms will come into play.
    Response: The Deltoid article is A beat up of Himalayan proportions.
  50. 2009 - 2nd hottest year on record while sun is coolest in a century
    Well yes HumanityRules, by why pretend that one should fit the earth's temperature evolution to a single contribution (whether ENSO or solar or CO2)? Why would we throw out everything that we know in pursuit of a spurious "argument" that we know is wrong? Obviously to reproduce the 20th century temperature we should include all of the contributions and their amplitudes and temporal variation. Anthropogenic greenhouse forcing predominates, but anthropogenic aerosols, black carbon, volcanoes, solar etc. all contribute to the temporal variation in surface temperature. See for example Figure 1 here: http://pubs.giss.nasa.gov/docs/2005/2005_Hansen_etal_1.pdf In relation to your post #38, to point out that solar irradiance change has made no significant contribution to warming since the 1950's, and likely a small cooling contribution since the mid 1980's, is not to dismiss solar irradiance changes as a contribution to surface temperature change - it just hasn't made a contribution since the 1950's. That's all very straightfoward isn't it? To address attribution to surface temperature variation we address all of the contributions according to their individual effects during the period of interest...

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