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Comments 107401 to 107450:

107401. TimTheToolMan at 08:32 AM on 10 October 2010
        How do we know CO2 is causing warming?
        You're both missing the point. If you look at the graph reposted by Doug you can see an amount of warming of the skin dependent on the amount of IR. It varies between about 0.1C and 0.3C. This is what they measured using 100W of downward LW radiation from clouds. If the amount of IR is reduced to 1/33 as is the effect of CO2, then the amount of warming will likely be be similarly reduced. It is the amount of warming of the skin that directly relates to any decrease in ocean heat loss decrease due to altered heat flux which is their theory. And you haven't even considered the fact that this heat loss hasn't been quantitatively considered and that is the point of the theory.
107402. Doug Bostrom at 07:57 AM on 10 October 2010
        It's the ocean
        At some point you're going to find it irresistible to use Google Scholar, Karamanski. Going directly to the well is much more efficient than relying on generalists such as myself to function as proxies hauling teaspoons of information. Plus, why trust me when you can eliminate a layer of fallible human nature and go straight to researchers themselves?
107403. Karamanski at 07:32 AM on 10 October 2010
        It's the ocean
        Are variations in the Atlantic meriodional overturning circulation driven by the imput of fresh water from the Arctic? Keenlyside et al 2008 did not state what the drivers for a weakening of the Atlantic meriodional overturning were, the paper just used historical analogs of certain regions of the North Atlantic and extrapolated current conditions using climate models. Comparing Keenlyside et al 2008 and the article you provided, the mechanism described in Keenlyside's paper seem to be cyclical on multidecal timescales, while the ocean conveyer discussed in the article you provided is changed by an external factor rather than internal variability. Are the Atlantic meridional overturning circulation and the Great Ocean Conveyor interelated?
107404. Eric (skeptic) at 05:43 AM on 10 October 2010
        The value of coherence in science
        Thanks Doug, I appreciate your feedback (no pun intended). Left my internet dongle at work but I downloaded the first paper to read offline. The second timed out so I will try somewhere else later.
107405. Doug Bostrom at 05:39 AM on 10 October 2010
        Newcomers, Start Here
        There's real value in remembering that folks may have more than one reason for tackling a problem. Here at SkS we have a few followers who're not particularly concerned about global warming but are quite clued in about the parlous state we'll be in when we've burned or otherwise depleted our endowment of liquid and gaseous hydrocarbons. A circumspect patriot looking forward to a prosperous future for America will include imagining means for how that future will be provided with agile transport and other things presently dependent on fossil fuels, particularly the easily portable types.
107406. Roger A. Wehage at 05:20 AM on 10 October 2010
        Newcomers, Start Here
        Well if "global warming" is responsible for a specific autumn weekends weather, why is it not be responsible for Katrina or the Lake Mead drought or floods in Pakistan ? Let me play the devil's advocate for a moment. And please understand that the following scenario does not reflect my attitude toward global warming. Maybe global warming did have something to do with Katrina or Lake Mead or Pakistan, but I wasn't there. People shouldn't be associating global warming with occasional high temperatures, rainfall, or droughts. What about the 11 straight days of record high temperatures in central Illinois back in the middle of July, 1936? Peoria, Illinois had some of its highest temperatures ever recorded, up to 113°F. Temperatures around here haven't exceeded 95°F in years. So did they have global warming 75 years ago too? Yes, parts of the Midwest have had significant rain the past two years, and we've had equally wet seasons before. But we've now had almost no rain the past six weeks, and little is forecast for the coming weeks. Is global warming causing this too? I've seen much worse droughts than what we are heading into now. I don't know anything about El Nino and La Nina, but experts say they are responsible for our changing climate conditions, not global warming. And there's nothing we can do about it. I'm a Patriotic American, and I generally don't go around telling people that the government shouldn't be wasting my money or telling me what to do about something they know nothing about. But I've had enough. Related to global warming, it is likely that for a long time to come, uninformed public attitude will carry much more clout than frantic scientific outcries.
107407. Doug Bostrom at 04:54 AM on 10 October 2010
        It's the ocean
        Karamanski, surface temperatures of the North Atlantic have a powerful influence on climate adjacent to the North Atlantic. There's a useful article here from Woods Hole providing a general explanation. It's a bit old, but it provides lots of search terms for following things forward.
107408. MarkR at 03:53 AM on 10 October 2010
        The first global warming skeptic
        Remember that a 1% increase in mean global temperature would be just under 3 C*, which is about half the difference between an ice age and today. So a 1% change could still be very important to us! (ofc, you need positive feedback to get the 1% reaction, but articles on here go through that pretty well too) *global temperature averages to something like 293 K iirc, so 10% more is 2.93 K = just under 3 C
107409. archiesteel at 03:14 AM on 10 October 2010
        It's the sun
        @Ken: "I notice that none of ya'll (Ned KR, kdkd) seem to accept my basic point that the area under ALL the forcing curves represents the total energy gained or lost by the Earth system." That's because the graph shows values starting from a relative reference point, and not an absolute level. You've been told this many times, and yet you refuse to hear it. This suggests you are not interested in debating, but instead pushing your point of view without addressing any challenges to it.
107410. archiesteel at 03:12 AM on 10 October 2010
        Carbon Dioxide - Everyone's Favorite Pollutant
        @RSVP: we already have a word for "too much water", it is called flooding.
107411. archiesteel at 03:07 AM on 10 October 2010
        Global warming is accelerating the global water cycle
        @fydijkstra, I have responded to your false claim that there has been no warming since 1998 here.
107412. archiesteel at 03:05 AM on 10 October 2010
        It hasn't warmed since 1998
        This is a response to fydijkstra in another thread, where he claimed there has not been any warming since 1998. fydijkstra, there has been warming since 1998, as this graph demonstrates: Second, 1998 was an exceptionally warm year. Using it as a starting point to determine a trend is cherry-picking at its best (not to mention the fact that the time frame is too short to indicate statistical significance). In spite of this, the graphs still show modest warming. However, look at what happens if we measure trends right before or after 1998: It's clear that starting in 1998 gives an erroneous idea of the actual temperature trends, which is why contrarians like to do so. That is what we call cherry-picking.
107413. archiesteel at 02:38 AM on 10 October 2010
        How do we know CO2 is causing warming?
        @TTTM: Okay, I'll give this one more try, but it's really starting to sound as if you *don't* want to understand. "I have read it and there is no analysis of how increased downward LW radiation from CO2 effects the amount of energy the ocean radiates. For that matter there isn't even an analysis of increased LW radiation from clouds and what effect that has on decreased radiation from the ocean." That's because LW from clouds and LW from CO2 are identical in nature, but that's not important because that wasn't the point of the article. "The only relevence to intensity of radiation is as relates to the fact the experiment measures SSTs relating to 100W downward LW radiation whereas CO2 only supplies 3W. The experiment therefore exagerates the effect." That's because the experiment isn't trying to measure the effect of CO2, but simply trying to show the mechanism by which IR (i.e. LW) radiation heats the upper ocean, even if IR radiation is stopped by the skin layer. Let me repeat so you can understand: the goal of the experiment was NOT to determined the amplitude of IR warming (from CO2 or any other source), but the mechanism by which the actual infrared radiation manages to heat the upper ocean under the skin layer. The fact that clouds send down more IR than CO2 only makes it easier to identify the mechanism. That's it, that's all. Anything else you read into this paper comes from you and you alone. So, no, I don't see a problem with the article, and you have failed to convincingly demonstrate that there is one. You still haven't said why you have no doubt your argument fails to convince me. Please elaborate.
107414. Ken Lambert at 01:42 AM on 10 October 2010
        Climate Cherry Pickers: Falling sea levels in 2010
        kdkd #83 BP's analysis is 'naive' - well what does a less 'naive' analysis reveal about the acceleration or deceleration of sea level rise??
107415. Ken Lambert at 01:21 AM on 10 October 2010
        It's the sun
        KR #637 "1750 has perhaps the best (not perfect) chance of being at equilibrium of those three dates - 900 temps have a steady downward trend, part of the Little Ice Age, I suspect, while 1880 is in early industrialization with numerous forcing changes from early CO2. But as the various forcings move around, the climate can only follow, only hitting equilibrium if (a) forcings don't change for a period long enough for the oceans to catch up, or (b) forcings reverse and pass climate change going the other way." Well I agree with you that AD1750 at near the Maunder Minimum would be closest to equilibrium so the temperature 'trajectory' is close to zero. Having said that - you seem to then confuse Temperature trajectories with forcings. I notice that none of ya'll (Ned KR, kdkd) seem to accept my basic point that the area under ALL the forcing curves represents the total energy gained or lost by the Earth system. I have found a summation of the 10 Radiative forcings from your chart at #623, here: Now this is interesting because if you take the areas under the "Sum of 10 Forcings" composite curve - you can see that from 1850 to about 1915 all the area under the curve is negative. According to this The Earth system has lost energy from 1850 to 1915 so we should see cooling. There is no significant cooling in temperatures in this period - in fact all charts show increasing temperatures since 1850. Clearly the only forcing which could maintain temperatures and add energy to offset the negative area was Solar, but this has been 'chart zeroed' at 1850 and has negligible area under its curve. If a S-B IR cooling response curve was added which corresponded to a temp rise of about 0.1 degC (probably more)in that period then another -0.4W/sq.m of IR cooling would add to the negative area under the combined curves. The only conclusion is that Solar should not have been zeroed, but entered the chart in AD1850 at about 0.2W/sq.m+, in order to maintain a positive area under the composite curves to support a 0.1 degC+ warming in that period. The same argument follows on for the rest of the chart up to date.
107416. muoncounter at 01:11 AM on 10 October 2010
        Newcomers, Start Here
        #40:"If global warming is causing this gorgeous weather, should I be hating it? ... How can Skeptical Science experts help to change these attitudes?" Not all is gorgeous weather. See the recent examples here. And then look here for the new paradigm.
107417. Karamanski at 01:08 AM on 10 October 2010
        It's the ocean
        Keenlyside et al 2008 states that a weakening of the Atlantic meriodional overturning circulation will cause North American and European temperatures to stall or cool slightly. How exactly would changes in Atlantic SSTs cause temperatures on the adjacent continents to cool? And the paper did not clarify which parts of the globe would continue to warm while North America and Europe cool slightly. Is it similer to the way ENSO affects global surface temperatures?
107418. muoncounter at 00:59 AM on 10 October 2010
        CO2 is not increasing
        "The 'airborne fraction' refers to the amount of human CO2 emissions remaining in the atmosphere." Denial of increasing atmospheric CO2 levels is absurd, but absurdity is a common theme among deniers. But in referring to an increase in the 'airborne fraction', you're really addressing the declining ability of natural 'sinks' to absorb excess CO2. Europe seems way ahead of the rest of the world in quantifying this: Researchers from 17 European countries cooperating in the EU-Integrated Project CarboEurope ... have compiled the first comprehensive greenhouse gas balance of Europe. Key findings: Net European sinks of CO2 only amount to 15% of fossil fuel emissions. For the EU as a whole, the sink capacity is only 11% of CO2 emissions. As sinks are degraded, airborne fraction must rise.
107419. RSVP at 00:58 AM on 10 October 2010
        Carbon Dioxide - Everyone's Favorite Pollutant
        micheal sweet #131 "I suggest you try to stay on the point." The discussion is whether CO2 is pollution or not. On one hand of the discussion, you have those that are saying it is clearly, seriously, obviously pollution; and on the other, a natural and skeptical questioning of this idea given the fact that CO2 forms a part of our natural environment. You make a good point about how the difference in the quantity of fertilizer can be a good or a bad thing, however following this logic the could be said of water and therefore lead one to then ask whether water should'nt be considered "pollution"? If so, then CO2 also, but if not, I think there is some room here to question this decision and also consider an alternative that deals more directly to the undesired sources of CO2.
107420. muoncounter at 00:31 AM on 10 October 2010
        Melting ice isn't warming the Arctic
        #10: "spring and summer in each hemisphere allow plants to grow and absorb CO2 while fall and winter see plants dying and releasing CO2." Of course. However, is biomass in Arctic latitudes sufficient to account for the largest amplitude seasonal swings on the planet? Or is CO2 essentially migrating in and out of the Arctic each season? Myneni et al. 1997 showed that it is sub-arctic latitudes (45-70N) that had the "greatest increase" in a consistent pattern of longer growing season, earlier snowmelt and higher amplitude CO2 cycles. (Don't you just love finding 13 year old papers that observed exactly what the skeptics/deniers are still insisting isn't happening?) "about a third of it melts out each year and the other two thirds often have widely spaced bits of ice with plenty of ocean surface receiving direct sunlight." Again, no question about that statement. But it suggests to me that summer melting is a consequence of warming; melting results in a feedback mechanism as open water has higher absorption than ice. It's this feedback that is the amplifier. But this article seems to imply the other way around: "Maximum warming occurs over the surface during winter while less surface warming is found in summer when heat is being used to melt sea ice." Shouldn't that be stated more clearly?
107421. Daniel Bailey at 00:24 AM on 10 October 2010
        Newcomers, Start Here
        I would augment Phil's excellent comment at 41 with this: By the time we could get the majority of the citizenry to demand action on CO2 emissions reductions, it will be too late to avoid all but the very worst of climate change's anticipated deleterious effects. Even a PETM-like extinction may become unavoidable if BAU continues much beyond 2050. The Yooper
107422. Karamanski at 00:22 AM on 10 October 2010
        Melting ice isn't warming the Arctic
        I also read in a paper, Shakhova(2010) that there is more methane in the Arctic atmosphere than in the global atmosphere. Does this extra methane Arctic temperatures somewhat higher than they would be otherwise. And could methane release from the East Siberian Arctic Shelf and thawing tundra be partially contributing to Arctic amplification? (Something Screen (2010) did not cover)
107423. Bob Lacatena at 00:21 AM on 10 October 2010
        Global warming impact on tropical species greater than expected
        One thing I've noticed here in New England this year is a dramatic increase in bugs, particularly spiders. They're absolutely everywhere. I can't believe how many inconvenient places I'm finding not one but five spider webs, how big the spiders are, and how many types I'm seeing that I've never noticed before. The frogs and toads are also far more numerous, and more importantly, far, far larger. For a long time the frogs have been vanishing, along with the wetlands (due to over development), but this year I'm finding toads all over the yard, each of them twice as big as anything I normally see. This is accompanied by more plant growth. Despite a serious drought, weeds, shrubs and plants are have spread to encroach on the yard like never before. All of this is relative to my experience of the past twenty years. It's never happened before in that time. Is it just an anomaly, or is it related to the focus of this article? The next few years will be interesting to watch.
107424. Phil at 00:13 AM on 10 October 2010
        Newcomers, Start Here
        If global warming is causing this gorgeous weather, should I be hating it? Should my hard-earned dollars be spent on fixing something that doesn't seem broken to me? Well if "global warming" is responsible for a specific autumn weekends weather, why is it not be responsible for Katrina or the Lake Mead drought or floods in Pakistan ? Attribution of any specific weather event to changes in climate is problematic (which is one reason why John Cooks favourite phrase "Climate trains the boxer, but weather throws the punches" is so apt - does the trainer know when the boxer will throw his next punch ?) but the suggestion might be that your wife is biased in attributing favourable events to AGW so that she can avoid thinking about the adverse affects.
107425. Karamanski at 00:08 AM on 10 October 2010
        It's Pacific Decadal Oscillation
        The causation is what I'm curious about. Is it the PDO index that resulted in the short-term correlation or is like you suggested global temperatures that are driving the PDO index? If the PDO index is responsible for the short-term correlation what is the physical mechanism by which the PDO would affect global temperatures?
107426. Daniel Bailey at 23:58 PM on 9 October 2010
        It's cooling
        Re: Richo (64) I would recommend a primer in the science to get yourself a good background. There are many uninformed commenters and websites out there, so it can often be difficult to discern the wheat from the chaff. I would begin by starting here Then go here And also watch this. Then come back to Skeptical Science if you have additional concerns, type a few words describing your concern in the Search box in the upper left of every page and see what has already been covered on that topic here. On those threads, many of your questions may have already been answered. If not, find the most appropriate thread and post your question there. Feed a hungry man a fish, and he will be full - for a while. Teach a hungry man to fish and he will never be hungry again. The Yooper
107427. Riccardo at 23:53 PM on 9 October 2010
        The first global warming skeptic
        The Inconvenient Skeptic I'm glad you accept that increased CO2 concentration does increase the energy absorbed. This was the very point I was making in the post, one thing that some people do not agree with. If it is significant or not is a completely different question. It's widely accepted, even in some skeptic quarters, that it amounts to about 3.7 W/m2 for doubling CO2 concentration. Compared to, say, thermal emission from the earth surface (see e.g. Trenberth 2009) it's a tiny fraction, not even 1%. Are we allowed to say it's insignificant just because it's "just" 1%? No for sure, it depends on how sensistive is the system under study. You can find more on this here.
107428. Daniel Bailey at 23:47 PM on 9 October 2010
        Melting ice isn't warming the Arctic
        Re: CBDunkerson (10) I noted your reference to the hemispheric seesaw in atmospheric CO2 and posted some available animations depicting it over on this thread. The Yooper
107429. Daniel Bailey at 23:45 PM on 9 October 2010
        CO2 is not increasing
        Based on CBD's comment:

        "There is a hemispheric seesaw in CO2 as spring and summer in each hemisphere allow plants to grow and absorb CO2 while fall and winter see plants dying and releasing CO2."

        I thought I would kick off this thread with some visual evidence of this seesaw: This one, using 2008 CarbonTracker data, animates changes over time. View is global, looking down. This one, from the GlobalView-CO2 Project (using data from 1979 to 2006), also animates changes over time. View is horizontal, pole-to-pole. A neat way to present a similar concept, but in a different way. I'll link this back to CBD's post on the other thread. The Yooper
107430. Richo at 23:37 PM on 9 October 2010
        It's cooling
        Hello all, I'm very new here to Skeptical Science, so bear with me if I have posted in the wrong section and too late. I found this site via my day to day viewing of "Ice age now", quite an interesting read, of which in one of Robert Felix's pages he mentioned this site, and I must thank him for it. This is certainly a grade above the rest, and truly is good to see facts over fiction. My question is: How is it, that if I do a quick check on every Australian city regarding the daily mean max temp since the start of Jan 2010, has shown an increase to the yearly average ? Thus far. If according to people like Robert Felix that the sun is in a quiet period and that the earth has not warmed lately and is cooling, how on "earth" can this be happening ? My monies on something called a "Greenhouse effect". And again, my apologies if have posted inappropriately. Richo.
        Response: Playing devil's advocate, one might answer that question by saying you can't gauge global temperature trends by looking at the temperature at a few selected cities or even over a single country. What you need to do is look at the global temperature record. Of course, what this shows is the hottest 12 months on record had just transpired recently: June 2009 to May 2010. So yes, we end up with the same question - if the sun has been cooling, why are we experiencing record warm temperatures this year?
        
        
        
107431. Roger A. Wehage at 23:35 PM on 9 October 2010
        Newcomers, Start Here
        I am a mechanical engineer and a novice when it comes to understanding global warming and attitudes toward it. Maybe some experts on Skeptical Science can help us novices understand what motivates objectors to relentlessly hold onto their positions in the face of solid scientific data and majority consensus. What percentage of objectors know they are correct, what percentage are unsure, and what percentage know they are lying. An objector may be novice or expert. A novice objector may be motivated by fear or ignorance; an expert by knowledge or greed. Novice objectors are too often shepherded by greedy objectors. It is now 7:30 a.m., October 9, 2010 in central Illinois. The temperature is predicted to reach a balmy record high of 88°F today and 87°F tomorrow. "What a wonderful weekend this is shaping up to be. If global warming is causing this gorgeous weather, should I be hating it? Should my hard-earned dollars be spent on fixing something that doesn't seem broken to me?" These are not my words, but of many around me who clearly have different attitudes toward global warming. How can Skeptical Science experts help to change these attitudes?
107432. CBDunkerson at 23:16 PM on 9 October 2010
        Global warming is accelerating the global water cycle
        fydijkstra, also the 'it has not warmed since 1998' fiction can be discussed here, here, or here.
107433. The Inconvenient Skeptic at 22:23 PM on 9 October 2010
        The first global warming skeptic
        Riccardo, You are correct that there is some variation and additional absorption in the vertical direction, but the difference is not significant. CO2 does have some additional absorption in the vertical. Brightness temperature (referenced by scaddenp) is interesting, but it is not a measure of energy or transmission, it is only a measure of perceived temperature. Brightness temperature can change without a change in the energy absorption. Also, using the data is not misleading when it is a direct plot of the data. A 200-year moving average would include recent data, but in the average 100 years ago. Adding 9 year averaged instrument would make no difference. I can show that on another forum if you wish.
107434. Berényi Péter at 22:20 PM on 9 October 2010
        Climate Cherry Pickers: Falling sea levels in 2010
        #73 doug_bostrom at 03:26 AM on 9 October, 2010 because of cultural matters tide gauges are located mostly in places where isostatic adjustment is such It is hardly a cultural matter tide gauges happen to be located along seashores. It's also hardly surprising as you press down the perimeter of a flexible plate floating on a viscosous fluid it sinks a bit while its central region rises.
107435. fydijkstra at 22:18 PM on 9 October 2010
        Global warming is accelerating the global water cycle
        Ned (#14) and Archiesteel (#10): Yes, there is a pause in global warming since 1998. Showing a rising trend 1994-2010 or 1979-2010 does not falsify the claim, that there is no warming since 1998. Almost every trend from an earlier year than 1998 to 2010 shows a rising trend, but even the most hard core climate scientists admit the pause since 1998. Remember the remarks in the ClimateGate e-mails: "it's a travesty that we can't explain it".
        Response: The "travesty" quote by Kevin Trenberth is not talking about a pause in surface temperature warming. What's he's talking about is that we know our planet is in an energy imbalance due to model simulations, satellite measurements and rising sea levels. However, our observation system is unable to account for all the heat accumulating in our climate. The full context of Trenberth's quote is discussed in "Trenberth can't account for the lack of warming" or if you want to get it from the horse's mouth (apologies to Dr Trenberth for the metaphor), I suggest reading the original paper that the quote referred to: An imperative for climate change planning: tracking Earth's global energy (Trenberth 2009).
107436. dorlomin at 22:13 PM on 9 October 2010
        The first global warming skeptic
        @ The Inconvenient Skeptic, if one points a pyrgeometers at the sky on a clear night what are we measuring?
107437. CBDunkerson at 20:51 PM on 9 October 2010
        It's Pacific Decadal Oscillation
        Karamanski #9: "But then in figure 2, there is good correlation between the PDO index and global temperatures if the linear warming trend is removed." I'm not sure how good this 'correlation' actually is (for instance a PDO peak corresponds to a temperature drop ~1994), but in any case correlation does not equal causation. Isn't it equally likely that fluctuations in global temperature drive the PDO? Or that a third factor (e.g. the solar irradiance cycle) is influencing both and producing the partial correlation you think you see?
107438. Johngee at 20:43 PM on 9 October 2010
        It's the sun
        Interesting... Found this via New Scientist and has been commented on fully at Real Climate. The Nature article can be linked through to via new scientist (couldn't get the nature link to work for some reason) "Joanna Haigh of Imperial College London studied satellite measurements of solar radiation between 2004 and 2007, when overall solar activity was in decline. The sun puts out less energy when its activity is low, but different types of radiation vary to different degrees. Until now, this had been poorly studied...Haigh's measurements showed that visible radiation increased between 2004 and 2007, when it was expected to decrease, and ultraviolet radiation dropped four times as much as predicted...Stefan Brönnimann of the University of Bern in Switzerland says Haigh's study shows the importance of looking at radiation changes in detail but cautions that the results could be a one-off. He points out that the sun's most recent cycle is known to have been atypical" (from new scientist) ...maybe something... may be nothing... more research is needed...
107439. CBDunkerson at 20:30 PM on 9 October 2010
        Melting ice isn't warming the Arctic
        Karamanski #6: "I heard it in the "Solar schmolar" video on the "its the sun" post." If so then you misheard. What that video says is that an increase in solar activity would be characterized by (among other things) more pronounced warming at the equator than at the poles. This is obvious since more sunlight hits the equator for a longer period of the year. It would be accurate to say that the video 'leaves out' that Arctic amplification would occur in either case, but the point it actually makes, that global warming caused by an increase in total solar irradiance would be most pronounced at the equator while observed warming is most pronounced at the poles, is valid. There has not been equatorial warming in excess of warming at the poles or even the mid-latitudes. Ergo, it's not the Sun.
107440. CBDunkerson at 20:18 PM on 9 October 2010
        Melting ice isn't warming the Arctic
        muoncounter #8, interesting images. There is a hemispheric seesaw in CO2 as spring and summer in each hemisphere allow plants to grow and absorb CO2 while fall and winter see plants dying and releasing CO2. I assume that is what is responsible for the high northern hemisphere CO2 levels in the images. Note however that the Arctic region isn't showing higher CO2 levels than much of the rest of the northern hemisphere... thus if this seasonal CO2 were responsible for Arctic amplification wouldn't we expect it to also be impacting most of North America? Also, we're talking about just a few PPM difference from the global average... the additional forcing from such a small change would be tiny. Basically something like; ln(394/390)*5.35 = 0.05 w/m^2. In any case, as the article above notes, the observed changes in snow and ice cover in the arctic would be expected to produce additional warming consistent with the measured increases. The arctic ocean used to be nearly completely ice covered all year round. Now about a third of it melts out each year and the other two thirds often have widely spaced bits of ice with plenty of ocean surface receiving direct sunlight. All that sunlight heating the Arctic ocean rather than reflecting off the ice generates a great deal of atmospheric warming.
107441. Doug Bostrom at 19:56 PM on 9 October 2010
        How do we know CO2 is causing warming?
        Unfortunately, CBDunkerson, I think Tim's misunderstanding is at a much more fundamental level, a failure to understand the point of Minnett's experiment.
107442. CBDunkerson at 19:51 PM on 9 October 2010
        How do we know CO2 is causing warming?
        To put it another way; The measured heat put off by a barbecue grill in use is much greater than the heat generated by sunlight hitting the grill when it is not in use. By your logic of taking amplitude of heating regardless of area or duration we would therefor have to conclude that the negligible heat generated by sunlight is not responsible for warming the planet, but rather the planet is kept warm by people barbecuing in their back yards. Further empirical evidence of this fact can be seen in that backyard barbecues are most common in the Summer, the warmest part of the year, and the temperature plummets in Winter when barbecuing is traditionally not performed.
107443. CBDunkerson at 19:38 PM on 9 October 2010
        How do we know CO2 is causing warming?
        TTTM #191: "So the effect they measured using clouds to create changes in downward LW radiation was 33 times greater than the effect that CO2 has on the ocean surface." Clouds are localized and temporary. CO2 increases are global and persistent. So sure... let's say individual cloud at a specific location might cause 33 times as much warming as the CO2 at that location alone. That cloud won't always be there... and it doesn't cover the entire planet. Further, clouds are formed from water vapor... which increases in the atmosphere as the temperature goes up... which increasing CO2 is causing to happen. So you've got increased CO2 warming + increased water vapor warming + increased cloud warming... all triggered by rising CO2 levels.
107444. Doug Bostrom at 18:26 PM on 9 October 2010
        How do we know CO2 is causing warming?
        Let's try again. It's mechanism that's talked of by Minnett, not intensity, Tim. The experiment does not exaggerate the the IR, it has nothing to do with intensity, rather it exploits a source of IR sufficiently powerful as to produce a usable signal to investigate the mechanism controlling skin temperature. Minnett does not suggest that C02 is going to cause such a powerful flux because of course he's not investigating the intensity of the flux. Can anybody else think of a way to explain this to Tim? How about an analogy. You want to investigate if a desk lamp is capable of warming an area on your desk. You shine a desk lamp on your desk from 12" away and find that the area under the lamp warms. If you'd chosen to shine the lamp at the desk from 24" away and found that your desk warmed in the illuminated area, would that have changed your opinion about how the desk warmed?
107445. Riccardo at 18:13 PM on 9 October 2010
        The first global warming skeptic
        Dr. Weart thanks a lot. I like the dam analogy too, it gives the right impression of something that can not be stopped forever. Sooner or later it will come out one way or another and in the meanwhile it produces an effect. Kooiti Masuda, you're right, I did not quote the source. It is from G.W. Petty 2006, Sundog Publishing, Madison, Wisconsin. In the sample pages online you will find more. Doug, hundreds of researchers did a terrific job, we're just trying to keep up. But apparently we're culturally lagging some 60 years; or is it just cultural internal variability? :) The Inconvenient Skeptic the horizontal direction is irrelevant/misleading. Look upward and think about how the absorption coefficient changes with altitude (Plass 1956) and how heat is redistributed (Hulburt 1931).
107446. Kooiti Masuda at 17:54 PM on 9 October 2010
        Carbon Dioxide - Everyone's Favorite Pollutant
        I do not think it a good idea to put the basis of "danger limit" on the knowledge of the last interglacial period. I have written some more as a comment (currently number 49) to the previous article "What constitutes 'safe' global warming?".
107447. TimTheToolMan at 17:52 PM on 9 October 2010
        How do we know CO2 is causing warming?
        "It has nothing to do with the intensity of the radiation." The only relevence to intensity of radiation is as relates to the fact the experiment measures SSTs relating to 100W downward LW radiation whereas CO2 only supplies 3W. The experiment therefore exagerates the effect. "Reducing the intensity of the downward radiation does not change how it interacts with sea water." Of course it does. Less downward LW radiation causes less of a warming effect. The graph you posted clearly shows that. Perhaps you need to take a step back. Do you agree with the RC article and acknowledge that there is an issue with ocean warming from CO2 at all?
107448. Kooiti Masuda at 17:42 PM on 9 October 2010
        What constitutes 'safe' global warming?
        I understand the author's good intention, but I am afraid that the current scientific knowledge about the last interglacial (Eemian) period is too weak a link to define the dangerous level of warming. The accuracy of estimate of global mean temperature as well as of sea level seems to have improved (though I still do not think accurate enough to be used as basis of policy making). My biggest doubt is whether we can consider that global mean temperature determines sea level (in somewhat mathematical terms, whether sea level is a function of global mean temperature alone). I do think that global mean temperature matters, but I also think that spatial and seasonal distribution of temperature, or factors other than temperature, may also be crucial. So the level of global mean temperature which is likely to cause dangerous sea level rise is under-determined by Eemian data. (This is a personal opinion of a scientist but not an expert of this specific issue.)
107449. Doug Bostrom at 17:17 PM on 9 October 2010
        How do we know CO2 is causing warming?
        Johnd, I highly recommend diving into a reasonably broad paper and following cites forwards and backwards. As I mentioned, the Ramanathan paper is an excellent place to start because of its sweeping objectives.
107450. GnDoty at 17:16 PM on 9 October 2010
        It's the sun
        I have been exploring a bit but could use some help. I'm looking for accurate temperature trends from 1800-1900. Also, earthquake frequency data during the same period including volcanic eruptions. I want to find if there is any changes in the data of significance post-1849.

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