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Comments 98801 to 98850:

98801. climatesight at 10:29 AM on 12 January 2011
       Could global warming be caused by natural cycles?
       Thanks for the suggestions re: images - I am on the lookout for something to visually break up the page and enhance understanding.
98802. Chris G at 10:15 AM on 12 January 2011
       Seawater Equilibria
       Sphaerica, Yeah, was afraid I was explaining a point already well understood. Mice work as well; the same principles apply, but I like the net as an analogy for a boundary layer. In any event, I think you have hit on the problem being related to timescales. Organic matter decays a lot faster than permanent snow cover advances; I would think. I suspect the Nat. Geoscience article linked by D Bailey was the primary source for the Science Daily article linked earlier. I'd also like to add some more complexity to the model by observing that there is an overturning of benthic ocean with the surface layers. I'm not sure what the rate of that is compared to the rate at which the surface layers find equilibrium with the atmosphere in terms of CO2. But in any event, I'm thinking that the upwelling water went down in a lower CO2 world; so, it might have a higher capacity to absorb CO2 than the water going down now will have when it returns. So, I'm forming a hypothesis that there will be echoes of past CO2 levels as the oceans overturn. Can't claim to sufficient knowledge to know if this hypothesis has any merit. My guess is that any echoes that do exist would be pretty blurry, considering there will be other factors at work and the rates of overturn for the worlds oceans are highly unlikely to be the same. It could also be that it stays down long enough that it is buffered back to a consistent level by chemistry that takes place with the rock and falling organic matter down there. I'll risk exposing a potentially foolish thought.
98803. GCNP58 at 10:10 AM on 12 January 2011
       Seawater Equilibria
       @#34: Just to be clear, I do not think the rise in atmospheric CO2 since the industrial revolution is due to the ocean outgassing. However, the well-seasoned skeptic will point out that all of the ocean deepwater has very high DIC concentration. Therefore, the observed meridional CO2 distribution with higher concentrations in the N. Hemisphere could be due to upwelling deepwater in the N. Pacific (for example). I doubt that time-dependent CO2 concentration measurements would show the rise in CO2 at Mauna Loa precedes the rise at Cape Gearheart by a few days (or whatever the mean transit time of tropospheric air masses across the Pacific), but that doesn't mean a skeptic wouldn't try to make the case. And it would be a bitch to beat down, in my opinion, because they would provide all sorts of wacked-out measurements showing you needed to bring a relatively small amount of deepwater to the surface and that area could easily be missing by the relatively coarse measurements over that huge area. No doubt this argument from the skeptic would contain several delusional assumptions, and violate some principles of ocean physics, but sorting out all the misconceptions would take days. Furthermore, at each turn the skeptic would layer on another level of scientific weirdness so you would be nearly literally tied in knots sorting out what was factual and what was fantasy. In order to avoid that waste of time (and this whole website is designed so that people will waste less time debating known science with skeptics), it is a good idea to nip it in the bud and understand the isotope argument *before* the whole upwelling line of attack gets started. I say this mainly because whatever you can do to create a latitudinal distribution of atmospheric CO2 from continental sources can also be done with some creative ocean physics and upwelling.
98804. apiratelooksat50 at 10:04 AM on 12 January 2011
       The science isn't settled
       KR, Thanks for the links. It will take me a while to check them out. Just being curious and not accusatory, do you and/or the other posters here look at other sites that are not pro-AGW? Pirate
98805. scaddenp at 09:56 AM on 12 January 2011
       Seawater Equilibria
       "Adds a bit of credence to the clathrate-gun hypothesis". I've discussed this a no. of times with our researchers in this area and while clathrates might be important for PETM, what evidence we have is negative for much influence on glacial cycle. If there was a significant contribution from clathrates to atmosphere, then surely you expect a fossil signature in ice core methane? What measurements I am aware of (sorry dont have reference as away from office) show CH4 is swamp origin.
98806. RW1 at 09:54 AM on 12 January 2011
       The Physical Chemistry of Carbon Dioxide Absorption
       hfranzen "Clarification: The absorption is a process in which carbon dioxide is excited from some rotational level in the ground vibrational state to some rotational level in the first excited vibrational state. The short explanation of the fact that half is returmed to the earth is: absorbed radiation is then reemitted through any of a number of processes and this emission is in all directions, i.e. half up and half down. Thus half the reemitted absorbed radiation returns to the earth as GHG flux. A slightly longer explanation of the reemission follows. Once this excitation has occurred the molecule either relaxes to the ground state or, more frequently, gives up the energy to the translational motion of another molecule (e.g. nitrogen) through collision. In the more probable collisional dectivation case this energy then becomes part of the thermal bath in which the molcules reside, in other words the atmosphere is locally heated above its steady state temperature. This excess bath energy is then lost through any of a myriad of collisional processes, say with the ubiquitous water molecules. This excitation is then lost through emission. In either case - direct emission or collisional deactivation follwed by remission from some other infrared active molecule the remmission is isottropic, i.e. nondirectional, and thus occurs with equal probability up or down." Thanks for the detailed reply, but I was looking for an actual number. The IPCC says a doubling of CO2 results in an intrinsic increase in surface power of 3.7 W/m^2. I've said before on here that if only half of the absorbed power affects the surface, the actual is only 1.85 W/m^2. What are you inputing in your formula? Since we both agree that because the re-radiation is isotropic, only half of the absorbed power can affect the surface and the other half is radiated in the same general direction it was already headed. The question then is specifically how much gross additional power is absorbed from a doubling of CO2?
98807. apiratelooksat50 at 09:53 AM on 12 January 2011
       Understanding the CO2 lag in past climate change
       To Trueofvoice @215; Nice catch on the JB reference. First person on any of these sites to do that. Do libs not listen to Buffett? ;) Also, Roy Clark was not referring to the climate holding steady, but instead to the establishment of the current climate and it's basic ranges of gaseous concentrations. It took billions of years of photosynthesis from cyanobacteria and blue-green algae to oxygenate the atmoshpere. Thanks for being civil.
98808. Albatross at 09:49 AM on 12 January 2011
       Could global warming be caused by natural cycles?
       Cruzn46, "Really? Tell me in PPM, like they do with CO2, how much water vapor is in the earth's atmosphere today. Then tell me how much was in the atmosphere in 1800." This is off topic. But how about you do calculations? And absolute WV content is measured in g/kg either as specific humidity or as mixing ratio (r). We know that mean RH is ~70%, and we know that the saturation vapor pressure (es) is determined by temperature alone. Between the equations for r and es and RH, and with knowledge of the mean global SAT (and applying) the assumption for constant global RH of 70% you could probably get an estimate of the mixing ratio circa 1880. It would be an interesting exercise, but completely unrelated to this post. Trenberth et al. (2005) found that from 1988 to 2003 the global precipitable water vapour (PWV; vertical integral of r though the atmospheric column) content increased by about 1.3% per decade over the oceans, and that this increase was in turn because of an increase in air temperature, with about a 9% increase in PWV per Kelvin, again over the global oceans. Results form that paper also offer a clue as to the value of mean r circa 1880. But again the answer would be off topic.
       Moderator Response: If anyone insists on pursuing this topic further, they should do so on a thread revealed by typing "water vapor" into the Search field at the top left of the page.
98809. Rob Honeycutt at 09:44 AM on 12 January 2011
       Could global warming be caused by natural cycles?
       Thanks Sphaerica! I just got this new track pad so I'm still learning it. That's a great tip. Sorry for the OT comments.
98810. RW1 at 09:41 AM on 12 January 2011
       The Physical Chemistry of Carbon Dioxide Absorption
       hfranzen, "I have not accounted for water vapor overlap. Since the absorptions are basically lines in the spectrum (a quantum mechanical effect -see the specrum from the astrophysics group at Ohio State in GWPPT6) it is only the occasional overlap that will have an effect and that to reduce the absorption by CO2 slightly. My guess is that this would result in less than a 10% reduction in the absorption and a far lesser effecct in the change in absorption with increasing CO2 ppm. Since my earth-year temperature increase result fits very well with what is actually observed (see #25 above) I am quite certain that overlap is not serious problem and what GWPPT6 shows is the basic thrust of what is occurring. The increase that I am calculating comes directly from the increase in the broad-band diffuse transmissivity as a result of the increase in the ppm of CO2. The latter is measured by the Keeling curve. The former results directly from the physics of GWPPT6 generalizing Beer's Law from s linear absorption of intensity to a broad-band, diffuse abosrption of flux. I input nothing that is not calculated or observed." With all due respect, you can't just make these assumptions. Water vapor absorbs a significant amount in the CO2 absorbing bands, especially on the high end above 15u but below too. Water vapor also exists in much higher concentrations than CO2. Then you have the issue of clouds as well. That is anywhere that is cloud covered, incrementally more power from additional CO2 would have little effect because the clouds would absorb the increased power anyway. Also, there is generally more water vapor in between the surface and the clouds, which would further reduce any effect from additional CO2 because of water vapor overlap. On top of all this, in really dry and cloudless areas where there is the least amount of overlap - i.e. where more CO2 has the highest potential to increase the total surface power, is also where IR heat energy most easily and quickly escapes out to space. This is easily demonstrated by how cold it gets at night in very dry areas with little water vapor or clouds in the atmosphere, such as the desert. Even during the summer, the nights can be very cold - much colder than more moist and/or cloudy areas at the same latitude. Unless you can properly account for and quantify all these things, your numbers really don't have much bearing on reality.
98811. Bob Lacatena at 09:32 AM on 12 January 2011
       Seawater Equilibria
       71, Dan Bailey, Not a problem. For safety I only drink Medieval Warm Beverages when reading about climate science.
98812. Bob Lacatena at 09:30 AM on 12 January 2011
       Could global warming be caused by natural cycles?
       30, 31, Rob Honeycutt, How to right click with a Mac trackpad (without using the dang control key).
98813. Anne-Marie Blackburn at 09:21 AM on 12 January 2011
       Understanding the CO2 lag in past climate change
       gallopingcamel The problem you have is that while we're talking about global warming, you're only focusing on some regions. And as I've already pointed out to you, regional factors can have a considerable impact on regional temperatures. To suggest that this is not what the theory states only shows that you haven't done your homework. You might want to read this FAQ, and then read the whole of chapter 11 for more information on regional climate change. Note also that uncertainties and difficulties are clearly stated. But by all means, if you can show that the AMO or any other factor can explain recent trends in global temperatures, please provide the evidence.
       Moderator Response: I deleted GC's comment because it is off topic for this thread, and because he knows perfectly well how to find the appropriate threads.
98814. Bibliovermis at 09:18 AM on 12 January 2011
       Understanding the CO2 lag in past climate change
       Why are you pointing to 0.6% of an area to refute the effect over the whole? What makes it more important than the other 99.4%
98815. cruzn246 at 09:16 AM on 12 January 2011
       Could global warming be caused by natural cycles?
       Re: cruzn246 (23) "When the PDO goes negative for a time more ice and snow build over the N hemisphere." Apparently you didn't read the post: PDO has NO long-term trend. Strike one. "That forgotten greenhouse gas that we still can't properly quantify worldwide, either presently or historically" Oh-so wrong. Very well studied, quantified and understood. Really? Tell me in PPM, like they do with CO2, how much water vapor is in the earth's atmosphere today. Then tell me how much was in the atmosphere in 1800. We just went through a summer with record high lows for most of July and August. We also had record high dewpoints, on average, over that period. H2O plays a huge role in a warming cycle that is very overlooked. Strike two. "unless some big old volcano blows up. Then we could get some major cooling" Anthopogenic-derived CO2 releases amount to 100X that of all of the world's volcanoes combined. Humans breath out 10X as much CO2 as those selfsame volcanoes do (but that human CO2 is part of the closed carbon cycle, unlike fossil fuel CO2). Anyway, volcanic cooling imposed on the globe is transient, unlike the documented effects of CO2. That's strike three, you're out. Next batter... (BTW, it's "Milankovitch") The Yooper Yeah, it is Milankovich. Dan, I'm not talking about your run of the mill explosions of volcanoes. I'm talking about the ones that truly alter climate, like Tambora or Mount Pinatubo.
       Moderator Response: [Daniel Bailey] Please read this post by Tamino. He proves the transient cooling of volcanoes by removing their effects and that of cyclical stuff (like El Nino) to get this (as you can see, no lasting presence of Pinatubo):
98816. Rob Honeycutt at 09:00 AM on 12 January 2011
       Could global warming be caused by natural cycles?
       Heehee... Daniel. I actually know the command (option+click). Just wanted to inject some humor. ;-)
       Moderator Response: [Daniel Bailey] Sorry, Rob. I'm so completely mouse-dependent I could not use my laptop without one.
98817. Rob Honeycutt at 08:59 AM on 12 January 2011
       Could global warming be caused by natural cycles?
       Daniel.... Um... Right click?
98818. h pierce at 08:58 AM on 12 January 2011
       Could global warming be caused by natural cycles?
       RE: Cyclic Climate Changes: What the Russians Say. The English translation of "Cyclic Climate Changes and Fish Productivity by L.B. Klyashtorin and A.A. Lyubushin can be downloaded for free thru this link: http://alexeylyubushin.narod.ru/Climate_Changes__and_Fish_Productivity.pdf? NB: This mongraph is 224 pages. By analyzing a number of time series of data related to climate, they found that the earth has global climate cycles of 50-70 years with an average of about 60 years with cool and warm phases of 30 years each. They summerize most of the studies that show how this cycle influences fish catches in the major fisheries. The last warm phase began in ca 1970-75 (aka the Great Shift) and ended in ca 2000. The global warming from ca 1975 is due in part to this warm phase. A cool phase has started and they predict it should last about 30 years. Several others studies have found this 60 year cycle. During the cool phase La Nina years usually out number El Nino years as was the case from ca 1940-70. KP @ #18 The 60 year cycle can be seen in the middle figure: 1850-1910 and 1910-70. However note that after 1970-75, the temperature did not decrease as it did at about 1940. Presumably this is due to extra heating caused by CO2 whose concentation began to increase at a greater rate than before that time. There is one other factor that contributes to global warming: Fine black dust from rubber and asphalt. I ask this simple question: Since 1900, where have the many billions (and billions and billions...!) of pounds of rubber and asphlate dust gone? The short simple answer is anywhere and everywhere. Synthetic rubber does not degrade upon exposure to sunlight, oxygen or microbes. A passenger car tire with an A treadware rating will lose about a pound of rubber over it lifetime. Can you imagine how much rubber 18 wheelers shed on the highways?
98819. Bob Lacatena at 08:55 AM on 12 January 2011
       Seawater Equilibria
       66, Chris G, Before I forget... I explained rate of reaction to my daughter using a different analogy. Imagine a gymnasium full of thousands of mice, and kids with mouse-scoopers and terrariums. The kids have to collect the mice and put them in the terrariums, from which they do occasionally escape. At first, catching mice is easy, because there are so many. With time, there are fewer, and the buggers are fast, so the catching is slower. At the same time, the job is never done, because at some point it gets so hard to find and catch mice that for every mouse they catch, another escapes. One can change that balance point (the rates of reaction) by adding more mice or kids (more reactants of one type or the other), making the terrariums more/less secure (changing the rate of the reverse reaction with an inhibitor), introducing better mouse-scoopers (catalysts) or taking them away and making them catch mice by hand, or by doing the catching when the children and mice are tired (equivalent to reducing the temperature in many reactions).
98820. Bob Lacatena at 08:49 AM on 12 January 2011
       Seawater Equilibria
       I said "restock" and "emit rather than absorb", but what I really meant was that the ocean/atmosphere would reach a balance in the exchange where CO₂ levels in both the ocean and the atmosphere would stay relatively constant until temperatures found a reason to drop.
98821. Bob Lacatena at 08:46 AM on 12 January 2011
       Seawater Equilibria
       67, Dan Bailey, 69, Me and Dan Bailey, I think my problem was this. The Mathews and Weaver letter says that if CO₂ emissions stopped abruptly, CO₂ levels would immediately begin to drop, because the ocean would continue to absorb the excess. I'm not sure, based on this post and discussion, that that is entirely true. As the partial pressure of CO₂ in the atmosphere drops, the ocean could may well at a certain point "restock" the atmosphere and keep CO₂ levels high. The point at which this happens depends partly on the temperature of the ocean when CO₂ emissions cease. The warmer the ocean is, the higher the ppm at which it is likely to emit rather than absorb. That would be bad, because it would keep CO₂ levels and temperatures elevated, which would in turn help to prevent the absorption of CO₂ by the ocean. I'd be curious if Dr. Franzen or anyone else could compute the curve... the ocean temperature vs. CO₂ ppm below/above which emission/absorption occurs. Some other process would be needed to get CO₂ out of the atmosphere. Could this be an important "tipping point" in our own decision of when to reduce CO₂ emissions? Or is the ocean likely to act as a very convenient sponge and clean up any mess that we make, no matter how tardy we are in recognizing our mistake?
       Moderator Response: [Daniel Bailey] You may want to put down any hot liquids before reading this then.
98822. Bob Lacatena at 08:32 AM on 12 January 2011
       Seawater Equilibria
       66, Chris G, 68, boba10960, Thanks to Chris for trying... although I am already comfortable with the concept of rate of reaction (and that variables can change the various rates "on either side of the net", resulting in different equilibrium points). My thought was more along the lines that boba10960 responded to... that on the land existing vegetation must be covered by snowfall as a glacial period progresses (perhaps I shouldn't have used the term "ice sheet") over much of the North American and Eurasian continents, and that would necessarily (I think) cover a whole lot of vegetation before it could decay. Subsequent warming would have to eventually reveal that carbon, which could proceed to decay, while the usual "new growth" isn't immediately present to do the opposite, and turn atmospheric CO₂ into "wood" at the same rate as the stalled decay could do the reverse. But boba10960's logic about being able to measure this due to changes in ocean acidity makes perfect sense. [That's the part I love about science, that Sherlock Holmesian inference that one can make from seemingly inconsequential details.] At the same time, while walking the dog (through the woods!) earlier I realized that the time scales in my scenario could be very wrong. As much as such vegetation would be covered/uncovered, it would just mean (in geologic terms) a pretty rapid return to the status quo of old/dead vegetation decays and new vegetation grows, resulting in a relative CO₂ balance there, maybe even a shift the other way as previously suggested (i.e. new growth extracts more carbon the old decay returns). So that image in my mind's eye was perhaps faulty, or at best uncertain. Thanks much, boba10960. I learned a lot today, and realized where I have big holes in my understanding and need to do more reading.
98823. Bob Lacatena at 08:18 AM on 12 January 2011
       Seawater Equilibria
       67, Dan Bailey, That was it! Yes! Now I just have to remember why I was asking about it. I know it had to do with this statement from that post:

       CO2 concentrations would start to fall immediately since the ocean and terrestrial biosphere would continue to absorb more carbon than they release as long as the CO2 level in the atmosphere is higher than pre-industrial levels (approximately).

       I just don't know what my train of thought was that wanted to get at that statement.
       Moderator Response: [Daniel Bailey] Try reading comments 38-47; maybe that'll jog your memory.
98824. Rob Honeycutt at 08:12 AM on 12 January 2011
       Could global warming be caused by natural cycles?
       Keithpickering @ 18... Wow. Is there a way to link to those graphs?
       Moderator Response: [Daniel Bailey] Rob, if Keith doesn't mind hosting them, you can just right-click on the desired graphic, select "view image" and then the URL of just the graphic will show in the location pane.
98825. Klaus Flemløse at 07:47 AM on 12 January 2011
       Graphs from the Zombie Wars
       Co2 and Global temperatures Muoncounter @ 72 Tanks for the link to T.G. Wilson Albatros @ 73 Thanks for the link to Kodre et al – it will take some time to digest this paper Archiesteel @ 75 I was surprise about Soares conclusion from Figures 10/11. Then I found out that taking year to year differences in two independent time series always will produce zero correlation. That my point of view. This can be proven mathematically or by simulation. This will also be true for the time series Keithpickering has used. Given me time and I will produce the graphics. The Soares conclusions in respect of these graphs are either caused by lack of knowledge or bad will. This result will be repeated again and again on skeptical blogs.Be prepared!
98826. muoncounter at 07:47 AM on 12 January 2011
       It's the sun
       #776: "disagree that average solar activity levels 1950-2000 are higher" Yep. See Deep solar minimum (from 2009) which reports: A 50-year low in solar wind pressure A 12-year low in solar "irradiance" A 55-year low in solar radio emissions
98827. Bibliovermis at 07:45 AM on 12 January 2011
       It's the sun
       Read the article, not just the one-liner summary.
98828. Bibliovermis at 07:43 AM on 12 January 2011
       It's the sun
       Please explain how a decreasing solar irradiance yields an increasing global temperature.
98829. boba10960 at 07:39 AM on 12 January 2011
       Seawater Equilibria
       Sphaerica, #62 Chris G #64 has already noted that there is little organic matter stored under ice sheets. Nevertheless, the hypothesis you mention is still advocated by some people, as described by Ning Zeng . However, we can be certain that the source of the rising atmospheric CO2 as the last ice age ended was the ocean and not on land, either under the ice sheets or in permafrost. If the CO2 had come from a source on land, then it would have acidified the ocean, as is happening today in response to burning fossil fuels. Stated another way, following the chemical equilibria described by Dr. Franzen, adding CO2 to the atmosphere from a source on land would have shifted the chemical reactions in seawater in the direction that dissolves more calcium carbonate in the deep sea. By contrast, extracting CO2 from the ocean by increasing the physical mixing that exchanges gases between the deep sea and the atmosphere (described in my earlier comment) would shift chemical equilibria in the direction that dissolves less calcium carbonate in the deep sea. The geological record indicates that calcium carbonate in deep-sea sediments was less dissolved (better preserved) during the time period that atmospheric CO2 was rising as the last ice age ended. From this, we know that the CO2 (at least most of it) came from the ocean, and not from a source on land.
98830. thepoodlebites at 07:35 AM on 12 January 2011
       It's the sun
       #775 I did read the "What the Science Says." The article is is not factually correct. Do you disagree with the NASA study? Do you disagree that average solar activity levels 1950-2000 are higher compared to those for 1900-1950?
       Moderator Response: [Daniel Bailey] Then you should read the Advanced version. Seems obvious to me (graphic from NASA/Solanki/PMOD data):
98831. Bibliovermis at 07:14 AM on 12 January 2011
       It's the sun
       Your understanding is incorrect. Please read the article you are replying to. As for a decrease in solar activity trumping the enhanced greenhouse effect, please use the search box to find the article on what would happen if the Sun returned to Maunder Minimum activity levels.
98832. thepoodlebites at 07:06 AM on 12 January 2011
       It's the sun
       My understanding is that solar activity levels have been above the historical norm since the 1940's, See Cycle 21-23, and the correlation between surface temperature anomalies and sunspot cycle length is interesting. A NASA study showed that solar activity influenced the observed warming of the previous century by 25%. But cycle 24 looks similar to cycles 5 and 6, during the Dalton Minumum. It's still too early to say for sure but it is possible that a weak cycle 24 may lead to subsequent global cooling.
98833. archiesteel at 06:56 AM on 12 January 2011
       Glaciers are growing
       @Starnut, I suggest you read less airport literature and more actual science in order to form a valid opinion on climate science.
98834. Daniel Bailey at 06:39 AM on 12 January 2011
       Could global warming be caused by natural cycles?
       My favorite sports broadcaster was Ernie Harwell from the Detroit Tigers. His favorite saying after a strike three call was "the batter just stood there like a house on the side of the road!" Skeptics think they have good reasons to believe in anything other than the science, but that leaves them unable to turn on the high fastball up in the zone and unable to hold up on the curveball in the dirt. Reminds me of this quote. The Yooper
98835. KR at 06:32 AM on 12 January 2011
       Understanding the CO2 lag in past climate change
       apiratelooksat50 - I have posted a response on Is the Science settled?
       Moderator Response: Thank you for redirecting the discussion!
98836. KR at 06:31 AM on 12 January 2011
       The science isn't settled
       apiratelooksat50 - Karl Popper's works have very little to directly do with the topic of CO2 lag. On the other hand, you appear to have raised the question of whether the science is settled. Let's look at the science. The planet is warming - Temperature records - Sea level rise - Arctic melting - Antarctic melting - Glacial retreat, Greenland melting - Crops and plants flowering earlier Hmm, plenty of evidence there. CO2 is causing the warming - Other forcings don't match recent warming - CO2 has enough of an effect, also here - Other causes can't explain it Looks like CO2. We're causing it - Isotopic evidence - Carbon cycle and emissions - Multiple lines of evidence What we have, apiratelooksat50, is multiple lines of evidence pointing in the same direction - towards human driven global warming. The only real uncertainties at this point are in regards to climate sensitivity - how much the temperature will go up based on our CO2 inputs. Our data indicates a minimum sensitivity to doubling CO2 of about 2.5°C (quite certain), with an upper limit of 4-5°C (nowhere near as certain, might be higher). Now, if you want to discuss uncertainty, I would recommend looking at the various, contradictory skeptical arguments. Hypotheses without evidence, or worse yet evidence contradicting them. Hypotheses that do not explain what we see. Those are uncertain.
98837. Daniel Bailey at 06:26 AM on 12 January 2011
       Seawater Equilibria
       Re: Sphaerica (62) Bob, I've thought about it and my mind still keeps coming back to this one: http://www.realclimate.org/index.php/archives/2010/03/climate-change-commitments/. I know it's not as old as what you're looking for, but it matches my memory of things. Romm also discusses it here. Sorry if it's not the one (unless you mean Solomon et al 2008?). The Yooper
       Moderator Response: There is a followup: Climate Change Commitment II.
98838. Chris G at 06:22 AM on 12 January 2011
       Seawater Equilibria
       Sphaerica #59, I remember an analogy used in 1st-year chemistry course that might be useful. Imagine there are tennis players on both sides of a court. Each player has a propensity for knocking balls across the net and that a higher concentration of balls means that it is easier for each player to put balls across the net. Imagine that instead of there only being one ball in the game, there are lots, and a player is free to hit any ball across the net. For any given amount of balls there are, after some time, an equilibrium will be established based on each players propensity to hit balls across. Now add or remove balls from one side, the concentrations of balls on both sides will come to a new balance point. There is no inherent balance point of the system; whatever balance point exists depends entirely on how many balls there are on the court and what each player's propensity for putting balls across is. In this case, balls are CO2 molecules and the propensity of the players is determined by the temperature of the sea and air. Higher temperatures give the ocean-based player a higher propensity for hitting balls across. Sorry for the overly simplistic analogy, but you seemed to be stuck on thinking that there was some set balance point, and there isn't.
98839. muoncounter at 05:55 AM on 12 January 2011
       Seawater Equilibria
       #52: "If the Arctic ever is ice free ... " ... it will be too late to worry about CO2. Open Arctic water will absorb summer sun; all that evaporation will make for some lovely early winter NH snow.
98840. Chris G at 05:50 AM on 12 January 2011
       Seawater Equilibria
       Sphaerica, #62, If you look under an ice sheet, you will find very little organic matter. In contast, regions with tundra and/or permafrost tend to have a lot of organic matter. The reason for this is that ice sheets flow from the center out. This flow scrapes the terrain underneath clean down to the rock. Also, in geologic time scales, the weathering of rock plays a large role in removing CO2 from the atmosphere. There is less weathering of rock under an ice sheet than there is when the rock is exposed to, umm, weather.
98841. muoncounter at 05:44 AM on 12 January 2011
       Could global warming be caused by natural cycles?
       #22: "variations that match the details but never account for the warming." Sphaerica speaks wisely. Anyone who thinks it's just a natural cycle should be asked to explain this graph from an MWP thread: There is nothing natural about what happened in the last 100 years. Natural excursions prior to the last century have neither the magnitude nor the rate of change. Those natural cycles are just noise in the presence of the recent trend. No amount of skeptical handwaving can make the contrast between recent temperatures and the 'natural cycles' go away. Yooper (#25), I believe the expression is 'Well bowled, Sir!' Perhaps Albatross can let us Yanks know how to be so polite.
98842. thepoodlebites at 05:36 AM on 12 January 2011
       It's the sun
       The current trend in sunspot number Cycle 24 is under the projected trend. NASA's 2006 forecast was ~150. The current predicted maximum of 90, in May 2013, may need further revision downward. I am reminded of the Penn and Livingston 2006 paper that showed a linear decline in umbral magnetic flux, suggesting that a continued decrease below 1500G may result in sunspots disappearing altogether.
       Moderator Response: So what? That's not relevant to the point of this post, which is a rebuttal of the skeptic argument that increase in the Sun's irradiation of the Earth is what has and is causing the Earth's temperature rise since about 1850.
98843. Chris G at 05:33 AM on 12 January 2011
       Seawater Equilibria
       TOP #51, #52, Yes, you are missing that the main point of the post is not that the oceans are not getting warmer, it is that they patently have not gotten warmer enough to support any claim that the additional CO2 in the atmosphere has the ocean as a source. Also, you are missing that the main reason that there is less Arctic ice is that the ocean is warming. A relatively warmer ocean will loose heat more rapidly than a cooler ocean, but the ocean is warming because it is receiving more energy. Receiving more energy will _not_ result in a cooling.
98844. Albatross at 05:13 AM on 12 January 2011
       Could global warming be caused by natural cycles?
       Daniel @25, Quite remarkably, cruzn246 somehow just managed to get an edge and caught behind, get bowled and then stumped ;) Everyone on the pitch is aghast...
98845. Daniel Bailey at 05:05 AM on 12 January 2011
       Could global warming be caused by natural cycles?
       Re: cruzn246 (23)

       "When the PDO goes negative for a time more ice and snow build over the N hemisphere."

       Apparently you didn't read the post: PDO has NO long-term trend. Strike one.

       "That forgotten greenhouse gas that we still can't properly quantify worldwide, either presently or historically"

       Oh-so wrong. Very well studied, quantified and understood. Strike two.

       "unless some big old volcano blows up. Then we could get some major cooling"

       Anthopogenic-derived CO2 releases amount to 100X that of all of the world's volcanoes combined. Humans breath out 10X as much CO2 as those selfsame volcanoes do (but that human CO2 is part of the closed carbon cycle, unlike fossil fuel CO2). Anyway, volcanic cooling imposed on the globe is transient, unlike the documented effects of CO2. That's strike three, you're out. Next batter... (BTW, it's "Milankovitch") The Yooper
98846. robert way at 04:55 AM on 12 January 2011
       Could global warming be caused by natural cycles?
       Sphaerica, I certainly understand the point of the post and I am just as much an AGW proponent as the next person. I just didn't think it was the appropriate way to graph those items because it makes clear synchronous behavior not be so apparent. The same can be said of divergences. Putting them on a similar scale which considers their standard deviation is probably the best manner or putting dual axis. I acknowledge that cycles are not necessarily causing the trend but I think it is important to acknowledge that some cycles contribute to it at times and hide it at times.
98847. cruzn246 at 04:44 AM on 12 January 2011
       Could global warming be caused by natural cycles?
       "ENSO (El Nino Southern Oscillation) and PDO (Pacific Decadal Oscillation) help to explain short-term variations, but have no long-term trend, warming or otherwise. Additionally, these cycles simply move thermal energy between the ocean and the atmosphere, and do not change the energy balance of the Earth." Of course they don't do it by themselves. Think of the effect they cause though. When the PDO goes negative for a time more ice and snow build over the N hemisphere. What happens then? More energy is reflected away; Less water vapor is in the air. (That forgotten greenhouse gas that we still can't properly quantify worldwide, either presently or historically) I still think we are in a warming cycle. Sure Milanovich is important, but there is a heck of a lot of variability in when the ice ages trip into motion within that cycle. When it does it is sudden. In fact Milanovich may just be coincidental rather than causative when it comes to Ice Ages. No one has ever come out and proven Milanovich causes the Ice Age cycle. I think it is all about when sea levels rise high enough to really upset the important ocean circulations that allow us to stay warm. Until then, we will probably have basically neutral periods followed by warming periods, unless some big old volcano blows up. Then we could get some major cooling. JMO, but there are good reasons to think this way.
       Moderator Response: [Daniel Bailey] See my response to you at comment 25 below.
98848. apiratelooksat50 at 04:09 AM on 12 January 2011
       Understanding the CO2 lag in past climate change
       1. It is easy to obtain confirmations, or verifications, for nearly every theory — if we look for confirmations. 2. Confirmations should count only if they are the result of risky predictions; that is to say, if, unenlightened by the theory in question, we should have expected an event which was incompatible with the theory — an event which would have refuted the theory. 3. Every "good" scientific theory is a prohibition: it forbids certain things to happen. The more a theory forbids, the better it is. 4. A theory which is not refutable by any conceivable event is non-scientific. Irrefutability is not a virtue of a theory (as people often think) but a vice. 5. Every genuine test of a theory is an attempt to falsify it, or to refute it. Testability is falsifiability; but there are degrees of testability: some theories are more testable, more exposed to refutation, than others; they take, as it were, greater risks. 6. Confirming evidence should not count except when it is the result of a genuine test of the theory; and this means that it can be presented as a serious but unsuccessful attempt to falsify the theory. 7. Some genuinely testable theories, when found to be false, are still upheld by their admirers — for example by introducing ad hoc some auxiliary assumption, or by reinterpreting the theory ad hoc in such a way that it escapes refutation. Such a procedure is always possible, but it rescues the theory from refutation only at the price of destroying, or at least lowering, its scientific status. Karl Popper, "Conjectures and Refutations", 1963
       Moderator Response: This belongs on the thread "The Science Isn't Settled." Anyone who wants to tespond, do so there. Responses here will be deleted.
98849. Albatross at 03:56 AM on 12 January 2011
       Not So Cool Predictions
       Daniel, Thanks for this. Yes, the numbers between the different data sets differ, and significantly so. Perplexing. It seems to me that part of the problem that is complicating matters is that there is not, to my knowledge, a universal standard to define deaths arising from extreme heat or cold. In England they seem to use a residual-type method and that gives really high numbers-- I do not like their method at all. Anyways, according to NOAA, between 1996 and 2009 there were 1957 heat related deaths in the USA (avg. 140), compared to only 357 for cold. So heat is still a bigger killer than is cold in the USA, at least for these data and for this time period. I excluded 1996, b/c it is an outlier, that year alone heat killed 1021 people. As George Monbiot pointed out recently, how the population deals with the cold depends on where you are on the planet and the local infrastructure. Temperatures near zero C in northern India and a hundred die. Near zero C in Thunder Bay in winter and some people are actually wearing T-shirts. The fact remains though that heat waves kill people in droves, especially in areas not accustomed to extreme heat. Witness the 2003 European heat wave (tens of thousands died), the Russian heat wave (again thousands died, although numbers are not easy to get from the Russians except that Moscow's mortality rate doubled during the heat wave). I find the argument "well cold kills too" to dismiss the increase in deaths (and misery) from heat stress as the frequency of heat waves ramps up in the future (as the planet continues to warm) a very weak one. On the up side, we can hope that there will likely be a decrease in cold weather -related mortality as the planet warms.
       Moderator Response: [Daniel Bailey] It was like, over on the Twice As Much Canada thread, when skeptics introduced the Christidis et al study as if it proved their point about extreme cold being more dangerous than extreme heat. Of couse, the Christidis et al study said no such thing (other than that human adaptation to extreme cold was better than human adaptation to extreme heat). Skeptics fail to take into account the dark side of extreme heat, wet-bulb temperature tolerability.
98850. Bob Lacatena at 03:54 AM on 12 January 2011
       Could global warming be caused by natural cycles?
       21, Robert Way, I'm not sure what you think that "standardizing" (when measuring two different things with different units of measure there is no standard) would do, but based on your comment about AMO and temperature for 1878, 1998 and 2010, you do seem to have missed the point. Certainly any of these observations will have oscillations that match the details (shape) of the temperature line, but not the trend. It is very clear that there is an upward trend in temperature, and no such upward trend in any of the other variables. You can mix and match them all you want, and yes, you can come up with variations that match the details but never account for the warming.

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