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krab at 16:56 PM on 16 September 2010How 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. -
Bern at 16:38 PM on 16 September 2010The 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. -
GnDoty at 16:22 PM on 16 September 2010It'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. -
archiesteel at 15:32 PM on 16 September 2010Video 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. -
CoalGeologist at 15:30 PM on 16 September 2010The 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! -
Albatross at 15:29 PM on 16 September 2010Video 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."
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cruzn246 at 15:29 PM on 16 September 2010The 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. -
cruzn246 at 15:19 PM on 16 September 2010The 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. -
HumanityRules at 15:18 PM on 16 September 2010Video 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. -
cruzn246 at 15:12 PM on 16 September 2010The 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. -
Bern at 14:32 PM on 16 September 2010The 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. -
dana1981 at 14:25 PM on 16 September 2010How 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. -
Daniel Bailey at 14:21 PM on 16 September 2010The 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 -
Albatross at 14:17 PM on 16 September 2010How 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. -
archiesteel at 14:12 PM on 16 September 2010Video 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. -
Daniel Bailey at 13:35 PM on 16 September 2010The 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 -
angliss at 13:25 PM on 16 September 2010The 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. -
HumanityRules at 13:13 PM on 16 September 2010Video 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. -
chris1204 at 12:47 PM on 16 September 2010How much did aerosols contribute to mid-20th century cooling?
A silly question: The 1940s coincided with some historically cataclysmic events - lots of oil spills from sunken ships, lots of dust from high explosive devices, cities burned up by conflagrations, industrial production soaring to meet the demands of the military world wide, aircraft flying in vast armadas across European skies, and so the list goes on. Any chance this might have had some climatic impacts? -
muoncounter at 12:23 PM on 16 September 2010The contradictory nature of global warming skepticism
#229: But we all know the reliability of those temperature records. Hey, I know: warming is really cooling when you look at these things in the mirror. -
macoles at 12:20 PM on 16 September 2010How much did aerosols contribute to mid-20th century cooling?
That was an interesting point in the section "Days cooled, but nights warmed". Can anyone point to a global anomaly graph that tracks the night time temperature minimums and C02 since the industrial revolution? It would make an excellent centrepiece for debunking CO2 scepticism. -
scaddenp at 12:18 PM on 16 September 2010It's El Niño
Erl - for a warming trend, you have to increase the net energy on the planet. Where is the evidence of this in ANY ocean cycle. While the initiation point of an ENSO event remains tricky, (is it wholly a dynamical phenomena?), I would say that other aspects are now pretty well understood. I also note that "ENSO" emerges in climate models, and yet these models do not create temperature trends unless there is a forcing (like CO2 or solar) applied. -
muoncounter at 12:17 PM on 16 September 2010How much did aerosols contribute to mid-20th century cooling?
#10: "during the mid-century cooling period, PDO was negative essentially the whole time" So I looked at a PDO data file and graphed it with global LOTI for the same period (1900-current). The mid-century negative certainly looks like the mid-century cooling, but the PDO seems to be touching negative territory since the late '90s: with no sign of any cooling.
PDO: Pink is summer 3 month average; light blue is winter. LOTI (dark blue) on the right-hand scale.
You can't have it both ways. Perhaps there is no real coupling between PDO and temp and the mid-century was mere correlation without you-know-what? Or perhaps any such coupling was faint and is now swamped by CO2?
In either case, its now PDO 0, aerosols 1.
Response: Note: added "width=450" to your image. I get a little grumpy when people break my web design. Just letting you know for future reference :-) -
scaddenp at 12:13 PM on 16 September 2010How we know the sun isn't causing global warming
Moved discussion to there... -
kdkd at 12:10 PM on 16 September 2010How much did aerosols contribute to mid-20th century cooling?
Daniel #6 (in reply to Rab #5 Thanks for the coherent explanation of that particular piece of erroneous thinking. You made me realise that this was another example of so-called climate sceptics (sub-consciously?) using the often uninformative technique of philosophical solipsism in an attempt to maximise perceived uncertainty. -
Daniel Bailey at 12:08 PM on 16 September 2010The contradictory nature of global warming skepticism
Stop the presses, this just in: NOAA reports 2010 hottest year on record so far. And the warming continues, anon. The Yooper -
dana1981 at 11:57 AM on 16 September 2010The Pacific Decadal Oscillation and global warming
The point still stands that PDO physically cannot cause a long-term global temperature trend, certainly not in both surface air and ocean temperatures. -
dana1981 at 11:53 AM on 16 September 2010How much did aerosols contribute to mid-20th century cooling?
It's valid to point out that during the mid-century cooling period, PDO was negative essentially the whole time (though still a relatively small impact on average global temperature). But PDO does not cause long-term temperature trends, as discussed in the rebuttal linked by muoncounter in #9. Nor can negative PDO explain the nighttime warming trend discussed above. -
Erl Happ at 11:39 AM on 16 September 2010How we know the sun isn't causing global warming
Ken, If we are to be sure that the sun is not responsible for recent climate change we that we fully comprehend all the possible linkages. Therefore, with all due respect to a man who is obviously very sophisticated, I urge you to consider the atmospheric dynamics described at http://climatechange1.wordpress.com/2010/08/17/is-enso-rather-than-a-%E2%80%98greenhouse-effect%E2%80%99-the-origin-of-%E2%80%98climate-change%E2%80%99-by-erl-happ/ It is generally acknowledged that the ENSO phenomenon is not understood. It is my belief that when it is understood, we will understand the the nature of the sun-climate link.Response: I suggest moving any discussion of ENSO to the "It's El Nino" page -
muoncounter at 11:36 AM on 16 September 2010How much did aerosols contribute to mid-20th century cooling?
And here's someone answering my question on a related thread. Gotta love skepticalscience! -
muoncounter at 11:28 AM on 16 September 2010How much did aerosols contribute to mid-20th century cooling?
#1: "Aerosols 0. PDO 2. " I'm mystified why so many people throw around these ocean cycles as an explanation for just about everything. Clearly I do not understand enough about ocean dynamics. But it is apparent just by inspection that there is no long term trend to these cycles:
From The PDO
From The AO and the NAO
So I have to ask: How can cycles with no long term coherency be the causes for an effect (increasing global temperatures) that has a long term trend? Wouldn't those cycles more likely be the causes of the short-term low-amplitude variations?
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nealjking at 11:28 AM on 16 September 2010Positive feedback means runaway warming
5, John Brookes: The carbon-cycle aspect has a positive feedback, because the increase in T => increase in CO2 => increase in greenhouse effect => increase in T. The T^4 radiated power has a kind of negative feedback, because the increase in T => increase in cooling => reduction of the increase in T. (But actually, T^4 behavior is not really the way the system works: If it did, we wouldn't be talking about the greenhouse effect.) -
nealjking at 11:18 AM on 16 September 2010Positive feedback means runaway warming
4, Lazy Teenager: - I don't quite get your point: The solubility of CO2 in water declines with increasing temperature. Last I heard, the uptake of CO2 has dropped in recent years, although up til now it has absorbed about half the CO2 produced by fossil fuels. - I don't understand the issue regarding equilibrium. -
Phila at 11:16 AM on 16 September 2010How much did aerosols contribute to mid-20th century cooling?
#! Thingadonta Aerosols are currently increasing in SE Asia significantly, but this doesnt correspond to any cooling (?). Please stop indulging in argument by assertion, and start providing credible evidence for your claims. Thanks! -
Daniel Bailey at 11:16 AM on 16 September 2010How much did aerosols contribute to mid-20th century cooling?
Re: Rab (5)"Drawing the blue lines in the top curve is not helpful. I realize this is often done to "guide the eye", but I think especially to non-scientists, it looks like you are trying to make more of the data than is there: nothing happened up to 1920, then something happened, linearly, changed completely all at once in 1940, and again in 1975."
Are you referring to Figure 1? If so, this is from a post by Tamino over at Open Mind. Tamino is a professional time-series analyst. He used this figure to illustrate how a time-series dataset can show natural "break points" in the data where a "tipping point" can be demonstrated to have occurred. The purpose of the blue line is not to "guide the eye". The red line is a loewess smooth to show the trend with less noise. I recommend following the link to Open Mind for further detail. The Yooper -
scaddenp at 11:08 AM on 16 September 2010Climate change: Water vapor makes for a wet argument
Just read your post more carefully... In ground thermometer, the measuring device equilibrates to surroundings by conduction and so is measurement the temperature of the immediate surroundings. With thermopile. BOTH ends of the thermopile equilibrate to surrounding by conduction, but only one end of the thermopile is heated by IR. This makes the device directional. If you turned it face the ground rather than the sky, then you measure the outgoing LR. Point it at the sky and you measure DLR (backradiation). If you measure both (and the short wave as well), then you can see the individual heat balance like the Trenberth diagram but on an hour by hour basis. And by the way, while I think Spencer is wrong on many things, he does science the right way - publishing his ideas in reputable journals. -
How much did aerosols contribute to mid-20th century cooling?
This is a good post except for one thing. Drawing the blue lines in the top curve is not helpful. I realize this is often done to "guide the eye", but I think especially to non-scientists, it looks like you are trying to make more of the data than is there: nothing happened up to 1920, then something happened, linearly, changed completely all at once in 1940, and again in 1975. I know you don't claim to say this, but to the non-scientist it seems like you are trying to prejudice the reader into seeing lines when in fact there is only noisy data. Leave the data alone and readers can see the trends for themselves. -
nealjking at 10:50 AM on 16 September 2010Positive feedback means runaway warming
3, Josie: I see it as runaway if the system goes to an extreme that is stopped only by a lack of resources of some sort: in the case of the amplifier, limits to power; in the case of the Venusian atmosphere, exhaustion of water. In this model, the feedback is positive but decreasing, so it just stops adding up. I consider it self-limiting, as opposed to runaway. -
HumanityRules at 10:43 AM on 16 September 2010Video update on Arctic sea ice in 2010
7.CBDunkerson I did better and read the published paper that presented this work. It contained nothing about previous years. If there were important multiyear observations he should have put them in the paper. Although it did have 14 uses of teh exciting "rotten ice" term. The real scientific content of that paper is that direct observations show that there are problems with the interpretation of the satellite data, as pointed out by Rob Honeycutt. Something I don't have a problem with. What's making the headlines, and what makes this a standout for warmists, is the lurid use of "rotten ice". Unfortunately Barber seems well aware this is the newsworthy content in his paper and is pushing that point. I have problems with that and with regard to any comments about long term ice thickness trends based on this work. I stick to my point this is one data point with no attempt at historical context. If Barber hadn't used "rotten ice" would this study represent anything new with regard post-2007 arctic ice? Apart from the satellite data insight. The fact that 2007 represented a clearing out of MYI is well known and ignored by Barber here. There are better post-2007 direct observations which suggest little has changed in the quality of the arctic sea ice and that the Barber (and POIMAS) predictions of it "continuing to disappear at an alarming rate" are exaggerations. The paper below suggests little has changed since 2007 which is remarkable given that this work was done in April 2007, before the huge clear out of MYI. The problem with Haas is he hasn't realised that sticking to the facts doesn't get you the headlines. You need plenty of fluff, something Barber seems to excel in. http://epic.awi.de/Publications/Haa2010b.pdf On PIOMAS I agree that the warmist blogosphere is in love with the PIOMAS model, I was asking whether the arctic science community felt the same way. I don't see it's widespread uptake as represented by published work. Show me the papers and I'm happy to concede the point. -
scaddenp at 10:41 AM on 16 September 2010How much did aerosols contribute to mid-20th century cooling?
Hmm. Globally, I thought aerosols were flat or declining Asia emitting more as industry moves there while reducing in the west? Anyway, remember that climate is not single-factor. The overall effect is sum of all forcings, positive and negative. Claiming PDO as cause may be mixing cause and effect. The PDO argument is somewhat moot anyway because there is no trend. -
dana1981 at 10:30 AM on 16 September 2010How much did aerosols contribute to mid-20th century cooling?
thingadonta - yes, PDO was another small contributor to the cooling during this period. And so were volcanoes, and black carbon caused some warming, etc. etc. I can't address every single global temperature influence in one post, so I covered the big ones. Your claim that aerosols are not causing any cooling in SE Asia is incorrect. Their local cooling effect is overwhelmed by anthropogenic warming, but that doesn't mean it doesn't exist. That's like saying 2 + (-1) = 1, therefore -1 isn't negative. -
adelady at 10:23 AM on 16 September 2010How much did aerosols contribute to mid-20th century cooling?
thingadonta. The chindian aerosols are one of the nasty effects in the wings. Anyone who says that CO2 emissions aren't lining up with the observed temperature increases should look at what could happen as aerosols reduce in the same way as those in advanced economies. -
thingadonta at 10:18 AM on 16 September 2010How much did aerosols contribute to mid-20th century cooling?
None of the your figures show the obvious correlation with mid 20th century cooling and the PDO cool phase of the mid 20th century. Aerosols are currently increasing in SE Asia significantly, but this doesnt correspond to any cooling (?). Aerosols 0. PDO 2. -
archiesteel at 08:49 AM on 16 September 2010The contradictory nature of global warming skepticism
@Eric: "If you look at my first post on the topic (102) I said since hunting was the main factor for the decline it should be addressed in the thread. You answer to that is now a straw man: "over-hunting"." That is *not* a strawman - if hunting is the main reason for the decline (which means that more bears die than what is required to sustain the population), then by definition it *is* over-hunting (or over-harvesting, etc.). As it is, nowhere in the link is anyone arguing that over-hunting is currently responsible for declining bear populations *overall*, therefore there is little evidence to support your claim. "Bottom line is I can't say that hunting deaths are greater than climate change deaths without a lot of missing information which I need to research." That's the most sensible thing you've said so far in this thread. Thank you. -
scaddenp at 08:48 AM on 16 September 2010Climate change: Water vapor makes for a wet argument
John - you are again making wrong assumptions. I really wish you would read the science of doom article I pointed to long ago. What you are describing is the laws of CONDUCTION. back radiation is not conduction. What you say makes no sense because of this fundamental difference. If you had no greenhouse gases, the warm ground would warm the atmosphere by conduction - just not very much. Spenser's experiment was aimed at reducing conduction effects and concentrating on the radiative energy transfers. -
archiesteel at 08:46 AM on 16 September 2010The contradictory nature of global warming skepticism
@Baz: "Ask yourself why I'm answering EVERYONE else but not you. Is it because your points are more clever than theirs, and that I have no counter-arguments to your points? Is it, mate? Really?" Yes, it is. (There can't be any other explanation, since I wasn't impolite to you.) Case in point: looking at the last three years (instead of five, or ten) shows dramatic warming. Why not see this as a sign the warming has resumed? -
Rob Honeycutt at 08:45 AM on 16 September 2010The contradictory nature of global warming skepticism
Baz... To follow up on the Yooper and your comment at 204, "I feel there are far too many closed minds in both camps." I think minds are less closed on the AGW side of the fence than you might be lead to believe. Yes, there are some aspects that climate scientists will battle to their dying breath over, but what they're battling over is not a matter of opinion. They're defending the basic scientific facts, as Daniel listed above. As a layman I've come to side with the AGW camp because I see them stating both the very clear science and presenting the aspects that are uncertain. Whereas on the other side I keep seeing isolated and contradictory arguments (the point of this blog post). The late Dr Stephen Schneider put it very well in this fairly recent TV discussion where he says, "If you see one side, either side, saying they KNOW the answer, they're wrong. Science doesn't do absolutes. But when you see someone saying, 'Here is what were sure of, here's what fairly certain of and here are the uncertainties' that is who you should be listening to." The basic science of AGW is, as so many say, done. Man made CO2 is warming the atmosphere. There are just no two ways about that. But there are uncertainties with feedbacks and climate sensitivity. Is it going to be 1.5C or 6.2C for doubling CO2? We simply do not yet know. But we do know enough to act to make sure that we do not expose the planet and human civilization to the potential catastrophe of, as Dr Richard Alley puts it, "the long tail of the distribution." (i.e., the possibility that things are going to be worse than we think). -
barry1487 at 08:33 AM on 16 September 2010What about that skeptic argument that Jupiter is warming?
You might want to add Uranus to the list. Apparently it's been cooling. (Link is to 2001 study - PDF) -
johnd at 08:27 AM on 16 September 2010Climate change: Water vapor makes for a wet argument
scaddenp at 07:35 AM, the point I was making is that what Spencer is tracking with his crude IR thermometer supposedly reading back radiation from the sky, is the same as that what a simple thermometer lying on the ground would track. The problem perhaps is the term back-radiation itself. I think everybody accepts that any body or matter that contains heat will exhibit such energy and allow the transfer of such heat through all mediums. Obviously any medium that has a higher heat content than those adjacent will transfer such energy at a rate relative to the heat differential that exists between them until such time equilibrium is reached. What is the situation then? No nett transfer of heat energy as outgoing and incoming are equal. In the physical world it is the nett results that are relevant, and back-radiation only affects the rate of the nett transfer of heat, not the direction. In the environment that Spencer conducted his experiment, and BOM record their terrestrial minimum, convection is the major form of heat transfer as it is in all the atmosphere, and it too responds accordingly to the magnitude of the heat differential. So it comes back to the original question, what was Spencer's experiment tracking that a thermometer lying on the ground wasn't? -
kdkd at 08:20 AM on 16 September 2010How we know the sun isn't causing global warming
KL #53 Two obvious problems with your post: 1. An incorrect assumption about TSI (see dana1981's response at #58) which means that the logic of your post is not sound. 2. You're still assuming that the OHC estimates are good enough to be able to draw strong conclusion from them.
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