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Comments 109901 to 109950:

  1. It's the sun
    GnDoty, it appears that you believe in a conspiracy by politicians and scientists to take all our money, remove all our freedoms and lord it over us ? Even if you don't actually believe all that, it would appear that your political beliefs are getting in the way of the facts. If that is not the case, you will obviously want to learn more and this website is good for that. Start here and here, then look at the following skeptical arguments : Climate's Changed Before CO2 Lags Temperature It's Freaking Cold ! There's No Correlation Between CO2 and Temperature Humans are too Insignificant to affect Global Climate Precipitation and Storm Changes (From the EPA - there are further links there) If you are truly serious about the truth about all this, you will look at the above and then come back and tell us what you disagree with and why.
    Moderator Response: Indeed, GnDoty, please not only read the posts at those links, but put your comments on whichever of those posts is relevant. This post is narrowly focused. Off topic comments usually are deleted.
  2. What's happening to glaciers globally?
    An interesting experience that Boba's graph reminded me of. I was completing multiple regression analysis of the mass balance record of the Lemon Creek Glacier, Alaska. This is a 50 year long record. I compared mass balance to 10 different circulation indices from PDO to ENSO and AO. However, I failed to remove the year column before running the data. Year came out with the best correlation of all. Simply put in the last 40 years anyway year has been a decent proxy for temperature.
  3. It's the sun
    Re: sun tzu (600) Spot-on, sir. Diagnosis 100% correct. Blinders off. The down side to being able to see is this realization: most people intuitively understand that we are "heading for a cliff", which is why they close their eyes, stick their fingers in the ears, bury their heads in the sand & repeatedly mumble "it can't happen, it can't happen..." It can, it will, it's almost here. Very sobering, this seeing thing. The Yooper
  4. It's the sun
    My replies have been between classes so I apologize for the short responses. "Has anyone said anything about "controlling" climate?" Well yes, you did when you said "Controlling? Well, that's another matter--but it will be tried over the next century, even if the attempt is blunt, unwieldy, and ultimately does more harm than good." So you're telling me we are more worried about the acidity of the ocean from CO2 saturation (which is balanced by higher temperatures causing more evaporation) than places like the mississipi delta dead zones due to fertilizers from agriculture up-river. I'm glad we agree this is about money and power.
  5. It's the sun
    GnDoty--that's ridiculous. Has anyone said anything about "controlling" climate? Are you saying that humans can't change climate? If we dropped ten nuclear bombs in ten large volcanoes, the thirty-year trends would certainly be affected, and that's a tiny amount of power we can wield over our environment. We have the power to kill most of the life on this planet in a matter of days. I wonder if that would affect climate? The oceans are becoming more acid due to relatively rapid saturation with CO2, and life, marine biologists reveal, is having a hard time adapting in such a short time. Where might this added CO2 have come from, I wonder? The time is long, long past where we wonder whether or not we have an effect on the nature of Earth. We eradicate species on a weekly basis. At what point in the process of replacing nature with concrete and asphalt do you suddenly realize that humans (a part of nature, by the way) are quite capable of changing climate? Controlling? Well, that's another matter--but it will be tried over the next century, even if the attempt is blunt, unwieldy, and ultimately does more harm than good. Climate certainly does change without the influence of humans, but you're willfully ignoring the nature of this recent, very rapid climate change that is occurring against the grain of several your major natural cycles. Why aren't "we" as a species taking responsibility for this change? I'll tell you: money and power.
  6. Why positive feedback doesn't necessarily lead to runaway warming
    ClimateWatcher #64, "Of course, if water vapor is providing positive feedback, one can still question why the warming rate is below the best estimate for the low end of IPCC projections." Only if they are living in a fantasy world where the statement above ISN'T nonsense. Observed warming is within the range of IPCC projections, not below the low end. Have you been listening to Monckton's fictional accounts of 'IPCC projections' which don't actually appear anywhere in the IPCC reports? "Both RSS and UAH, with recent corrections, indicate cooling trends in the pre 1998 data." Oddly the people who actually produce the RSS and UAH data all say that their results show long term warming trends... both pre and post 1998. "Also lost in that tale is that the -middle- troposphere, where models predict the greatest warming, indicates much less warming for both RSS and UAH." Source?
  7. It's the sun
    GnDoty writes: "I find it interesting the only rebuttle to sun spots driving temperature is a 40 trend, which is a blink of the eye in geologic time." Yes... because it is well known that sunlight travels at speeds best measured in 'geologic time'. PLONK
  8. It's the sun
    Sorry for my typo, which should have read 40 year trend. You can cherry pick time periods all you want. The fact is climate changes without the influence of man. That's why we find whale fossils in the Sahara Desert and shark teeth in north Texas. The position you are taking is essentially that man is more powerful than mother nature and can control climate. Do you honestly believe humans can prevent climatic events like the many that have occurred in the past. If you answer no for any of those events, then why are we focusing on it. I'll answer for you. Money and power.
  9. Why positive feedback doesn't necessarily lead to runaway warming
    >>>"I take this as saying: The observations must >>>be wrong because they don't match the theory." > >I think it's perfectly reasonable for a paper to >point out that a certain set of observations doesn't >make any sense within current theory. Of course, if water vapor is providing positive feedback, one can still question why the warming rate is below the best estimate for the low end of IPCC projections. >The UAH measurements on tropospheric >warming/cooling were discrepant with ground-level >temperature measurements for over 10 years, and >all the climate community could say for sure was >that it didn't make any sense - until the UAH team >finally figured out their data analysis was in error. Well, for the MSU era, the MSU-LT (of both RSS and UAH ) track pretty well with the Land/Ocean indices (both CRU and GISS). The difference was the observations subsequent to the last big el nino, and not the corrections, however. Both RSS and UAH, with recent corrections, indicate cooling trends in the pre 1998 data. Also lost in that tale is that the -middle- troposphere, where models predict the greatest warming, indicates much less warming for both RSS and UAH.
  10. The contradictory nature of global warming skepticism
    Daniel... And the scary part of this being the hottest year on record is, 1) We're now in an La Nina 2) The PDO is negative 3) We in a deep solar minimum I shudder to think what's going to happen when we flip over to the other side of those three. "Whoops! I think we just found Trenberth's 'missing heat.'"
  11. What's happening to glaciers globally?
    Agreed, I have to be careful how things are interpreted. Changed accordingly.
  12. It's the sun
    GnDoty, as adelady writes, the sunspot numbers representing that "40 trend" (going back to the 60s) are ACTUAL not modelled - apart from the projected figures beyond 2010, of course. Anyway, how about going back to 1850. What's the correlation there ? Shall we go further ?
  13. It's the sun
    GnDoty writes: I find it interesting the only rebuttle to sun spots driving temperature is a 40 trend, which is a blink of the eye in geologic time. So? Why does this strike you as interesting? Let's say you want to explain the modern temperature rise. You have two possible culprits: solar activity or CO2. Prior to this time period (say, 1800s to 1960-ish) solar activity and CO2 were both increasing, so it's not possible to rule either of them out. From the 1970s on, however, solar activity starts decreasing, while CO2 keeps increasing. Thus, solar activity can't explain the post-1970 rise in temperature but CO2 can. It's fairly simple logic. Looking at solar activity over longer time periods is no doubt scientifically interesting, but not really necessary to rule out solar as the cause of recent warming.
  14. It's El Niño
    scaddenup #2 My understanding is that ENSO, La Nina, AMO etc are internal re-distributions of heat energy around the globe - not overall gain or loss of heat from the Earth system to space by forcing imbalances.
  15. How we know the sun isn't causing global warming
    KL #53 I meant Arkadiusz, not Andreas. Arkadiusz - your posts are full of interest if hard to read and absorb. A mine of information.
  16. It's the sun
    GnDoty at 23:42 PM on 16 September, 2010 .... physical and not computer modelling. I'm not sure what you're getting at. I had a quick look through Jmurphy's references and there were a couple of projected trends but apart from that, all the other information, like the one I referred you to, were simply records of temperatures or observations of sunspots and related phenomena. Do you have a specific question about any of these?
  17. How we know the sun isn't causing global warming
    dana1981 #51 The Anthropogenic (AG) forcings and natural 'Solar' in Fig 2.4 AR4 are calculated 'changes' from AD1750, the critical point being that the AG forcings were 'zero' in AD1750, so the AG values are referenced to a zero baseline; whereas the Solar forcing in AD1750 is not nesessarily 'zero'. That means that you can reconstruct the AG forcings (with proxies and theory) back to AD1750 and draw the curves from a 'zero' baseline in AD1750. The area under these curves represents the energy added or subtracted from the Earth system. If you do the same for Solar forcing you need to know what the value was in AD1750, referenced to a 'zero' solar forcing. This 'zero' solar forcing would be the TSI where the Earth was neither warming nor cooling. Since the Earth was warming out of the Maunder Minimum from about AD1715 the chances are that Solar forcing was greater than zero in AD1750, and that the area under a forcing curve drawn from AD1750 to the present will have a stating point above zero, which adds a slice of area (energy) 250 years x starting point (AD1750) forcing in W/sq.m. This could be a large number of Joules. kdkd #59 - this negates your point 1) and 2) OHC measurement is not the issue here - just that 90%+ of any long term heat gain must store in the oceans.
  18. It's the sun
    I find it interesting the only rebuttle to sun spots driving temperature is a 40 trend, which is a blink of the eye in geologic time. If you feel compelled to reveal further evidence, please do so as physical, and not computer modeling.
  19. What's happening to glaciers globally?
    The mass balance of glaciers which in turn controls long term terminus behavior is not primarily the result of localized conditions. This is borne out by the consistency of mass balance response regionally and terminus behavior regionally. Localized conditions generate some differences from glacier to glacier, but withing a mountain range the responses tend to be dominantly similar. Note the graph that I used in the BAMS 2008 report on North American glacier mass balance or at Realclimate. Thus, we have found that in terms of year to year climate change it is regional, local, global in terms of order of importance. The high correlation North Cascades glacier mass balance-Table 3 exceeding 0.8 on all of the glaciers.
  20. Arkadiusz Semczyszak at 22:26 PM on 16 September 2010
    The Pacific Decadal Oscillation and global warming
    Here CDIAC you can see as "powerful" smoothed CO2 data from ice cores - the Law Dome.
  21. Video update on Arctic sea ice in 2010
    HR, you concede that Barber's direct ice observations contradicted interpretations of the satellite data... but simultaneously claim that this is invalid because of the TERM he used to describe the difference? Seriously, this hangup on semantics seems to be an ongoing theme amongst many of the anti-science objections. The satellite analysis showed what was thought to be solid thick multi-year ice that would block ship travel through the region. Barber's direct examination found that this was instead actually small chunks of ice held together by a thin crust... and that these sections easily broke apart and posed no significant barrier to navigation at all. Is all that agreed? If so, then I really don't care WHAT the 'ice which does not block navigation' is called. It is a new scientific finding with significant implications.
  22. What's happening to glaciers globally?
    If this works then the inverted glacier mass balance (Cogley, 2009) overlain on the GISS temperature record, both since 1880, will appear below:
    Moderator Response: It almost worked ... you had an excess "/" at the end of your file name. I've edited it.
  23. The Pacific Decadal Oscillation and global warming
    Here's a figure I posted in another thread not long ago. The red and brown lines are temperature (from satellites & met stations, respectively). The green lines are CO2 (ice core & atmospheric measurements). The blue line is PDO. The yellow line is solar irradiance. Presumably, the observed temperature trend is the result of the interactions of all forcings, including those shown here and others as well. But this graph makes it clear that neither ocean oscillations nor solar irradiance is the dominant cause of the observed temperature trend since the 1970s. CO2 provides a much better fit. Adding in the effects of other greenhouse gases, and subtracting the effects of volcanic and anthropogenic aerosols, would make this match even closer. -------------- The fine print: PDO data from University of Washington. Surface temperatures from GISS land+ocean. Satellite temperatures from RSS. Law Dome CO2 from NOAA NCDC. Mauna Loa CO2 from NOAA ESRL. PDO and temperature data shown in monthly and 120-month LOESS smoothed versions. Law Dome CO2 dating based on "air age" with 20-year smoothing. Mauna Loa CO2 (monthly) are seasonally adjusted. Both CO2 data sets were log-transformed (base 2). Data sets with differing units (PDO, temperature, log[CO2]) have been scaled to fit on the same graph. Solar irradiance data from University of Colorado, shown annually and with a 22-year LOESS smoothing function.
  24. Arkadiusz Semczyszak at 22:02 PM on 16 September 2010
    What's happening to glaciers globally?
    I would have just loved that it was only now (2006) for example, glaciers in the Alps 'release' houses from the eighteenth century, crushed by the glaciers. Probably around 171? -177? A.D. these glaciers have a similar or even less coverage, than they do now.
  25. Arkadiusz Semczyszak at 21:51 PM on 16 September 2010
    The Pacific Decadal Oscillation and global warming
    The PDO is closely linked of SOI and ENSO. The relationship between Pacific Decadal and Southern Oscillations: Implications for the climate of northwestern Baja California., Pavia, 2009.: “These results confirm that El Niño-Southern Oscillation (ENSO) forces the PDO.” Professor Horst Malberg, analyzed ENSO and SOI in paper: La Niña - El Niño und der solare Einfluss, (Editor: Institut für Meteorologie - Berlin, 2009 - work is only available in German), write: “Any temperature variation demonstrates the weakness of the working hypothesis of a dominant influence of anthropogenic CO2 effect on climate change. For the voiced suspicion that the anthropogenic greenhouse effect would be, if not before 1950, significantly influence at least after 1950, climate change, there is no real climatological evidence. Everything indicates that it is also in the last six decades by the IPCC in the postulated dominant CO2 greenhouse effect on global temperature change (warming) just a sham causality.”
  26. What's happening to glaciers globally?
    Excellent post! Very clear and understandable to anyone. Maybe this is obvious to everyone, but I hadn't realized until seeing this post that the glacier mass balance is so closely linked to global temperature. For example, if you invert the graph of Cogley, 2009 from 1880-2010 and overlay it on the GISS Land-Ocean temperature relationship, the similarity is striking. (I just did that but am unable to post a graph).
  27. Climate change: Water vapor makes for a wet argument
    scaddenp at 11:08 AM, Phil, the thermometer used by BOM to measure terrestrial minimum temperature is not IN the ground, but "placed close to the horizontal and just above the surface of the ground" as described on the BOM site. This is a picture of such a thermometer in place. As can be seen the bulb is not in contact with anything, only the capillary tube being in contact with the wooden base. The reason I introduced the matter of the terrestrial minimum temperature is because it measures conditions that are closer to those that prevail at the point where evaporation takes place. As Spencer's experiment shows, whether it is day or night, the ambient air temperature is not an indicator at all of what heat energy is made available at the surface to drive the evaporation process. Whilst there may be sophisticated instruments to measure back radiation, it basically only measures what a simple thermometer on the ground measures, or what a bare-footed kid chasing the cows in on a frosty morning, and again at high noon, and that is that what his face feels 1.2m above the ground is not what the soles of his feet feel, if he lets them touch the ground long enough to register any sensation that is. That is exactly where the energy that drives evaporation is inputted into the process. If back radiation is any factor at all in driving the evaporation process, then consider this. The lowest overnight temperature at the surface is the baseline that determines what heat energy is left in the atmosphere once all that accumulated from the input of solar energy has been dissipated. Following the energy budget diagram posted earlier, it is clear that all the flows of heat energy are depending either directly or indirectly on the input of solar energy. After the terrestrial minimum temperatures have been reached any increase in energy that will manifest itself as radiation between the surface and the atmosphere can only have come from the solar energy absorbed either directly into the atmosphere, or after having first been absorbed by the land and oceans and then transferred by convection, evaporation or radiation into the atmosphere. Apart from the energy being transferred by radiation and back radiation which indicates a nett transfer of 66 from the surface to the atmosphere, the single biggest form of nett heat transfer from the surface to the atmosphere is evaporation at 78. As mentioned by someone earlier, the diagram is not a very good one at representing the true energy budget and flow of heat, but if anyone persists with using it simply because there is none better, then it has to be considered as a whole, and defended by correlating what it appears to illustrate with what actually occurs in the physical world. So far I haven't seen that being the case. I also think that Spencer gets some things wrong, though I do believe he is right regarding negative feedback. I also agree he is doing things the right way, though from a different perspective. Instead of looking to add further confirmation to what many accept as a foregone conclusion, an easy thing to do, he applies some lateral thinking, an approach sadly lacking in a world ruled by the confines of logic, and challenges that perhaps of the two faces of a coin, the heads side is not the necessarily the defining side.
  28. Hurricanes And Climate Change: Boy Is This Science Not Settled!
    Interesting report from Jeff Masters's Wunderblog : This morning's unexpected intensification of Hurricane Julia into a Category 4 storm with 135 mph winds has set a new record--Julia is now the strongest hurricane on record so far east. When one considers that earlier this year, Hurricane Earl became the fourth strongest hurricane so far north, it appears that this year's record SSTs have significantly expanded the area over which major hurricanes can exist over the Atlantic. This morning is just the second time in recorded history that two simultaneous Category 4 or stronger storms have occurred in the Atlantic. The only other occurrence was on 06 UTC September 16, 1926, when the Great Miami Hurricane and Hurricane Four were both Category 4 storms for a six-hour period. The were also two years, 1999 and 1958, when we missed having two simultaneous Category 4 hurricanes by six hours. Julia's ascension to Category 4 status makes it the 4th Category 4 storm of the year. Only two other seasons have had as many as five Category 4 or stronger storms (2005 and 1999), so 2010 ranks in 3rd place in this statistic. This year is also the earliest a fourth Category 4 or stronger storm has formed (though the fourth Category 4 of 1999, Hurricane Gert, formed just 3 hours later on today's date in 1999.) We've also had four Cat 4+ storms in just twenty days, which beats the previous record for shortest time span for four Cat 4+ storms to appear. The previous record was 1999, 24 days (thanks to Phil Klozbach of CSU for this stat.)
  29. It's the sun
    GnDoty You might find this USA site handy. This is for the global stats, but you can choose a selection of national and global reports at the top. I had a quick look at one of the USA and there didn't seem to be much difference, but you might be able to track down what you're after with more focused steps through the topics. Global anomalies to August
  30. It's the sun
    GnDoty wrote : "I feel it is important to mention many areas are cooler than normal. For example, parts of China and the Pacific Northwest of the US." It's only important if it's true, but your statement would only be true if you replaced the word "many" with "some". If you believe otherwise, please post some evidence. Meanwhile, here is the true state of affairs : 2010 Tied with 1998 as Warmest Global Temperature on Record (Have a look at the Temperature Anomalies graphic) GnDoty wrote : "In the 1920's, Russia had over 600,000 deaths due to malaria. Thought I would throw that out there before you mentioned anything about AGW spreading disease." That is simply a diversion and this is not the place to go into types of malaria and treatments available back in the 1920s. With regard to sunspots, look here. Also, a quick search found a page with this graph. Does the declining trend since the 60s correlate with the increasing temperatures we have been experiencing ?
  31. How much did aerosols contribute to mid-20th century cooling?
    krab: I quite like the blue line - it shows the relationship to the smoth and the raw points quite nicely. It's possible the raw points shouldn't be joined though ;)
  32. It's the sun
    I feel it is important to mention many areas are cooler than normal. For example, parts of China and the Pacific Northwest of the US. In the 1920's, Russia had over 600,000 deaths due to malaria. Thought I would throw that out there before you mentioned anything about AGW spreading disease. Pre-industrial era, an increase in temperature first must happen for increased oceanic evaporation which increases greenhouse gases. I also would be interested in a response to my statement on the correlation of sun spot activity and temperature.
    Response: For the record, I wasn't talking about AGW spreading disease in Russia - the 15,000 deaths were directly heat related due to record hot temperatures.

    To answer your question "can you really deny the fact that as sun spot activity increases, so do temperatures?", no, you cannot deny that. As the sun gets brighter (eg - more sunspots), the Earth receives more energy and warms. Conversely, as the sunspot activity falls, this equates to less energy reaching the Earth. Over the last 40 years while global temperatures have been rising, the sun has shown a slight cooling trend. This means the sun cannot be causing recent global warming and in fact, is slightly masking the global warming trend.
  33. How much did aerosols contribute to mid-20th century cooling?
    @Daniel Bailey: I saw the post at Open Mind but neglected to respond. As Tamino and the present post state, the influences change smoothly, not discontinuously, so there is no warrant for drawing straight lines. Tamino says: "But it’s still a pretty good approximation to model global temperature as a piecewise-linear function." I say: "It's an unwarranted approximation." You may disagree. You may want to cherish the notion that Tamino is more qualified than I am. @kdkd: So now I'm a sceptic? My friends (and enemies) would find that hilarious. Try not to jump to conclusions. I am not disputing any of the results. I am complaining about the way they are communicated to non-scientists. Isn't such communication the main purpose of this blog? The blue lines hinder rather than help.
  34. The Pacific Decadal Oscillation and global warming
    Some good points there, CoalGeologist, but the real question is, what does the correlation represent? Is the "Mostly Cool" period lining up with the low rate of global warming due to the PDO driving temperatures globally, or global temperatures driving the PDO? Given what else we know about the forcings during the 20th century, particularly the variations in solar irradiance, aerosols (see the next blog post), and CO2 concentrations, I think we can say it's most likely the latter - the PDO is affected by global temperature changes, even though it's generally neutral overall. When you think about it, if the bulk of the extra heat is soaked up by the oceans, then it makes a lot of sense that this might result in significant changes in circulation patterns.
  35. It's the sun
    JMurphy, If you believe that we are experiencing record high temperatures this year, could you please explain two things. Why is Texas experiencing below average temperatures? Also, Texas experienced the fourth most rainfall for the month of July ever this year. Furthermore, how can you say CO2 drives temperature when ice core samples from Greenland show the opposite and an 800 year lag for the increase in CO2 for the last 12,000 years. In addition, can you really deny the fact that as sun spot activity increases, so do temperatures? I'll leave it there for now. I simply want to keep this discussion honest so people like Sun Tzu can form an un-biased opinion.
    Response: "Why is Texas experiencing below average temperatures?"

    Some regions will experience cool conditions but a number of countries are experiencing record high temperatures this year. 15,000 Russians died in their record heat wave last month. A few months before that, thousands of Pakistanis and Indians died in record heat waves. When you average out the whole planet, we're currently experiencing record high global temperatures.

    "how can you say CO2 drives temperature"

    We know this because the increased greenhouse effect due to rising CO2 has been directly observed by satellites and confirmed by surface measurements. In other words, several independent measurements directly observe that CO2 is trapping heat.

    "ice core samples from Greenland show the opposite and an 800 year lag for the increase in CO2 for the last 12,000 years"

    This is discussed in detail on the "CO2 lags temperature" page. In short, warming causes CO2 rise and rising CO2 causes warming. This is a positive feedback and part of the reason that the planet is able to get out of an ice age.
  36. Video update on Arctic sea ice in 2010
    @HR: "While the debate remains tribal I'm going to look for words to describe one of the tribes." That seems like an unecessary mental shortcut, especially considering the motley crew of those who disbelieve part or all of AGW, many of which hold contradictory opinions. It's much more constructive to debate the science. "Haas has things relatively unchanged between 2007 and 2009." ...for *old* ice, not for arctic ice in general. The paper makes this quite clear. It also mentions the fact there's *less* old ice, though its thickness remains the same. This seems to go contrary to your argument. "It's interesting what you choose to leave out with your [....]. Is this evidence of your own bias?" Not at all. I edited that part for brevity only; it does not contradict my point, nor does it support yours. The only "interesting" thing about it is how you seem to think it does. It doesn't. The facts remain: both Barber's and Haas' mention loss of old ice, which leads to a simple conclusion: MYI is going down as a result of increased temperatures. Considering you cited the Haas paper, we have to assume you agree with the science in it, and therefore agree that MYI is decreasing.
  37. The Pacific Decadal Oscillation and global warming
    This is a bit confusing for non-experts (such as me). Having also read the comments from "It's Pacific Decadal Oscillation" and the limited number of other sources I could access, Bern has got it right, but there's something more to the story!. Confusion arises because of the difference between: 1) "Pacific Decadal Oscillation" (PDO), which is a generic term describing any multi-decadal cyclicity in temperature anywhere in the Pacific Ocean, and 2) "PDO Index", ("PDOI") which indicates the regionally averaged temperature of the Northern Pacific Ocean. The PDOI provides an indicator of the timing and cyclicity of the PDO. Within the Pacific, however, are smaller-scale temperature zones that show temperature cycles occurring on the same cyclicity as the PDO, but having opposite trends!!! PDO Index is defined as:
    "[...] the leading PC [principal component] of monthly SST anomalies in the North Pacific Ocean, poleward of 20N. The monthly mean global average SST anomalies are removed to separate this pattern of variability from any "global warming" signal that may be present in the data." (emphasis added).
    (Source: http://jisao.washington.edu/pdo/PDO.latest) Thus, the PDO Index indicates the average temperature of the entire northern Pacific Ocean, normalized for the global increase in temperature. This trend (squiggly blue line) shows two broad cycles:
    1) 1890-1924: Mostly Cool Period 2) 1925-1946: Mostly Warm Period 3) 1947-1976: Mostly Cool Period 4) 1976- ~mid-1990s: Mostly Warm Period
    It is important to note that these trends describe the average temperature across the entire northern Pacific. When the data are gridded into individual cells, then contoured, this produces the colored patterns shown in the map above. Two "snapshots" are depicted... one representing a "Warm" phase, the other reprenting a "Cool" phase. (It's hard to say exactly what time period each snapshot represents.) In any case, this is where it gets a bit more confusing. In the "Warm" phase, the predominant trend is that of cool water across most of the northern Pacific. And the "Cool" phase is dominated by an extensive tract of warm water in the northern Pacific. To understand the origin of the terms, you need to look at the water along the coasts of Alaska, extending downward into the Pacific Northwest (of the USA). You'll see that the water there is the opposite color of the predominant trend. Keep in mind that the point of the paper by Hare (1996) was to interpret the impact of the PDO on salmon fishery, so they were mostly considering the temperatures of the near-shore waters. The important aspect of the maps, noted by John Cook, is that the water sloshes this way and that. Areas that are warm in one cycle tend to be cool in the next, and vice versa. There's no net impact on global warming. Or is there?! The cool PDOI interval (My #3) corresponds to the broad decline in the rate of global warming seen in the red "Global Temperature Anomaly" trend, and the warm PDOI (My #4) coincides with the more rapid increase in the Global Temperature Anomaly... so while I don't believe that the PDO can account for the overall warming trend in the Global Anomaly, it's not inappropriate for skeptics to point out the correlation!
  38. Video update on Arctic sea ice in 2010
    HR, could we please drop the rhetoric and stick to the science. I find this whole discussion of "tribes" rather juvenile and not constructive. Have you considered this? And the recent decline in Arctic sea is indeed significant. A paper just out by Polyak et al. (2010) which places the current loss of ice in context. Specifically, Polyak et al. state: "The current reduction in Arctic ice cover started in the late 19th century, consistent with the rapidly warming climate, and became very pronounced over the last three decades. This ice loss appears to be unmatched over at least the last few thousand years and unexplainable by any of the known natural variabilities."
  39. The Pacific Decadal Oscillation and global warming
    Also note that that the rate of rise during the last positive phase, from the early 20s to the mid 40s, was almost the same as what we have had since the mid 70s. The latest was a bit more but so was the strength and length of the positive PDO.
  40. The Pacific Decadal Oscillation and global warming
    And if you look at the charts you will see the shift to negative does not instantly cool things. Just look at the shift of the PDO in the early 40s. The temperature dip followed it by about 5 years. The Negative trend has to sustain a few years to affect temps.
  41. Video update on Arctic sea ice in 2010
    48.archiesteel While the debate remains tribal I'm going to look for words to describe one of the tribes. I'd prefer that this was dropped though. You OK with everybody elses biases? Haas has things relatively unchanged between 2007 and 2009. I don't see how I'm wrong. It's interesting what you choose to leave out with your [....]. Is this evidence of your own bias? "It seems that consequences of strong melt and ice export during and after the summer record minimum 2007 may have been compensated for by weather patterns in 2008 that were not conducive to high melt and ice dispersal in summer and may have fostered enhanced thermodynamic ice growth during a colder winter 2008/09 with less snow accumulation, as suggested by anecdotal in-situ observations in spring 2009" The loss occured in 2007 where is the evidence 2009 measurements represent a continuation of a decline? Because Barber doesn't give use any historical perspective he seems to attribute what happened in 2007 to 2009. This is the point I've been making. 2009 does have lower MYI than early 2007 but is this a consequence of what is happening in 2009 (which is Barbers suggestion) or what happened in 2007? I still don't understand how Barber can make a statement such as "continuing to disappear at a very alarming rate" based on one data point. It doesn't make scientific sense to me, it's propaganda, it's alarmism. As I said I don't object to the true scientific content of his paper. Here are a couple of similar eye-witness ship board reports that seem to stick to the facts rather than go for the sensationalism (here and here. Enjoy). I don't understand why people don't accept the only thing that makes Barber's work stand out from the rest of the arctic ice data, and why it's been so newsworthy, is his "rotten ice" hyperbole.
  42. The Pacific Decadal Oscillation and global warming
    Oh man, c'mon folks. The PDO doesn't just keep rising. It's either Positive or Negative or neutral. If you look at when it was mostly neutral or negative, in the periods from 1900 to 1920 and 1943-1977, temperatures didn't go up even though the trend for the whole period was up. this is about a silly comparison.
  43. The Pacific Decadal Oscillation and global warming
    angliss, I'm speaking as a non-expert layman here, but as I see it, the reason the PDO index is de-trended is so that it is a measure of short-term variability in sea surface temperatures. If we compare with ENSO, for example, the Southern Oscillation Index is based on a comparison of sea surface temperatures in the eastern and western waters of the south pacific - by it's very nature, it removes any long-term warming or cooling trends, as presumably both areas are subject to the same long-term shift. The PDO index, on the other hand, is defined as "average Pacific Ocean SST anomalies north of 20ºN". As there is no direct comparison with SST anomalies anywhere else, they define the "anywhere else" as the entirety of the world's oceans, so the PDO index is, in fact, a comparison of the north Pacific SST with the rest of the world's oceans. On that basis, it's not so much "removing the trend", as providing an index that gives an idea of how the north Pacific is behaving compared to the rest of the world's oceans. Otherwise, you'd have people arguing "See, the PDO is causing SST rise!", when the PDO would in fact be a measure of SST... or, in other words, "Global warming is caused by the oceans warming", which is an absurdly circular argument.
  44. How much did aerosols contribute to mid-20th century cooling?
    macoles - greater warming at night than day is on my list of anthropogenic global warming fingerprints, though the particular study I referenced only went back to 1951.
  45. The contradictory nature of global warming skepticism
    Re: Berényi Péter (165) Sorry, was traveling when you posted this. Just wanted to credit you with a deft, understated touch that resonated well with a superb choice of graphic. Very apropos. Bravo, Sir. The Yooper
  46. How much did aerosols contribute to mid-20th century cooling?
    Hi John, Fascinating post, this is something that I have often pondered. I was wondering, is there any evidence form observatories which indicate/suggest that the luminosity of certain stars decreased during the time in question? If so, that would be another confirmation that a contributing factor to the cooling was increased aerosol loading. I know incredibly little about astronomy, so apologies in advance if this is a daft question.
  47. Video update on Arctic sea ice in 2010
    @HumanityRules: ok, first your use of the expression "warmist" clearly indicates your strong bias. You probably want to avoid that. Second, you make a misleading statement in your post: "There are better post-2007 direct observations which suggest little has changed in the quality of the arctic sea ice" That's not what the paper claims. It says that little has changed in the thickness of *old* ice, not Arctic ice in general: From the Abstract: "Comparison with previous EM surveys shows that modal thicknesses of old ice had changed little since 2007, and remained within the expected range of natural variability." From the Conclusion: "We conclude that older sea ice in much of the Arctic Ocean was of similar or even slightly larger thickness in April 2009 relative to conditions in 2007, but within the expected range of interannual variability. However, the volume of older ice may have been less overall due to a lower areal coverage, and because our surveys were still spatially limited. [...] The balance between high melt rates and import of old ice into the Beaufort and Chukchi Seas will be an important variable in determining potential recovery or further Arctic ice mass loss [Barber et al., 2009]." Less older ice means the old ice is disappearing, which means that this paper (which clearly recognize the ice loss) supports Barber (or is at least consistent with - makes sense, since they cite him). Perhaps the next time you should actually read the research paper, with an open mind, and not simply peruse it in order to find ammunition.
  48. The contradictory nature of global warming skepticism
    Re: muoncounter (230) Dude, everyone knows that in the darkness of the mirror the true heart of skepticism darkly lies. Speaking of skepticism, if it walks like a duck... The Yooper
  49. The Pacific Decadal Oscillation and global warming
    Agreed, dana1981. But the graph and explanation as shown above doesn't work as an explanation of why the PDO can't cause long-term global temperature change. This one tripped me up so bad a while back that I emailed Nathan Mantua about it a year or so ago. It's unfortunately a common error, but it's still an error that should be corrected here.
  50. Video update on Arctic sea ice in 2010
    10.Trueofvoice Its not that I don't like the way the image looks. It's that it exaggerates the thinness of the FYI in order to re-inforce the "rotten ice" meme. It's appears to be scientifically inaccurate.

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