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Comments 123651 to 123700:

123651. petewsh61 at 06:59 AM on 21 February 2010
        Is CO2 a pollutant?
        Concentration and context matter. Certain forms of nitrogen compounds (nitrates, etc.) are a necessary nutrient for plant growth. But, too much nitrogen in aquatic systems can cause anthropogenic eutrophication and a resulting loss in biodiversity. Think scum filled ponds and dead zones in coastal zones. Most people have no issue regarding excess nitrogen as a pollutant. No different form CO2.
123652. Doug Bostrom at 06:57 AM on 21 February 2010
        On the reliability of the U.S. Surface Temperature Record
        jpark at 06:16 AM on 21 February, 2010 My perspective is different than yours, but I too had a tough time retraining myself to make my comments appropriate to the tone John Cook is trying to establish here. I never realized how much snark I'd grown accustomed to radiating 'til I tried putting my oar in here. Take a another look at the "Comments Policy" is my suggestion to you.
123653. Peter Hogarth at 06:49 AM on 21 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        It is worth having a look on Leif Svalgaards research web site: I think he has also discussed the "original" Maunder minimum and possible scenarios of solar activity during it. http://www.leif.org/research/ Pertinent to the original title of the post, it seems we are now well on the way out of the solar minimum (not sure from above it would make much difference?). See: http://www.leif.org/research/TSI-SORCE-2008-now.png Also of more general interest is his "TSI (Reconstructions).xls" also on this page, along with many fascinating papers and presentations. One question is that if the early 20th century warming was not down to increasing solar activity, which appears quite likely from his and the more recent work illustrated neatly on his chart, then what other forcings (or more likely what combination of forcings) can be invoked, or do they need to be?
123654. Riccardo at 05:25 AM on 21 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        Ranger, please read the comment policy before complaining for deleted posts.
123655. Doug Bostrom at 05:17 AM on 21 February 2010
        Is CO2 a pollutant?
        suibhne at 00:02 AM on 21 February, 2010 That's good, we (appear) to agree the reflector will allow the lightbulb to become warmer, even though the temperature of the reflector is cooler than the lightbulb. Extending the model, assuming the reflector is not perfectly reflective and has thermal conductivity the system would of course eventually reach equilibrium as the reflector radiated into the surrounding void, with the lightbulb remaining at a higher temperature than it would if the reflector were not present.
123656. Riccardo at 05:00 AM on 21 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        Turboblocke, it would be better if you provide full citation of the paper. Models do not assume any amplification not they are calibrated against recent temperature. Models are given the known physics and some parametrization for effects that can not be modeled from scratch. More on climate models here.
123657. Riccardo at 04:50 AM on 21 February 2010
        It's cosmic rays
        Turboblocke, there's something missing in the claim you're reporting. Twomey effect and Mie scattering are two different things.
123658. Tom Dayton at 04:32 AM on 21 February 2010
        Is CO2 a pollutant?
        suibhne, reflected IR would indeed return to the metal. Light as "particles" is very, very different from the particleness of people exiting a football stadium. Light also is waves that pass through each other and proceed to their respective destinations, despite "interfering" with each other on the way. This topic has been covered in the comments on the "CO2 Is Not the Only Driver of Climate" thread, including links to animations. Start with Riccardo's comment 05:28 AM on 6 November. Then click on the links in my three successive comments from 10:11 AM, 10:30, and 11:16.
123659. Turboblocke at 04:10 AM on 21 February 2010
        It's cosmic rays
        BTW hope you don't mind me asking here, but someone claims that the Twomey effect is wrong for dealing with clouds and that "Mie scattering" is more appropriate. Anyone know anything about this?
123660. Turboblocke at 04:05 AM on 21 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        On another board a commentator made the following claim: "the model assumes maximum water vapour amplification and minimum solar amplification" and "The model has been calibrated to recent temperature rise using a set of assumptions which have yet to be verified by adequate matching of predicted temperatures to actual temperatures, and that might take another 20 years." I couldn't access the paper, so could someone please answer the points above?
123661. Ned at 03:26 AM on 21 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        Ranger writes: Just googled "wildfires co2". There sure seems to be a lot of concern, in some circles of the scientific community that wildfires are of concern to the amount of co2 in the atmosphere. Fires do add some CO2 to the atmosphere but before the arrival of humans on the scene this was balanced by the removal of CO2 as plants regrow following the fires. If you think about it, this has to happen -- otherwise the entire biosphere would be burned up and earth would be a desert. Over the course of the next century, the amount of CO2 from fires will be small compared to the amount from fossil fuels. We should not trust human nature and it lust for weath and power. When money and power are at stake, human beings are capable of great evils. With the amount of power and money at stake I am skeptical. Skeptical about what? That's not very clear. I assume you aren't saying that the people who are trying to raise concerns about climate change are motivated by money and power. Obviously, (a) most scientists could make a lot more money doing something else; (b) insofar as wealth and power have an effect on this, it comes from the opposite side (ExxonMobil etc. have infinitely more money and power than anybody on the must-stop-global-warming side). Am I remembering right that in the 1970's greenhouse gasses were suppose to reflect the energy from the sun and caused a new ice age? No, that's a misconception. See here: What 1970s science said about global cooling
123662. pmheideman at 03:18 AM on 21 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        "Am I remembering right that in the 1970's greenhouse gasses were suppose to reflect the energy from the sun and caused a new ice age? " you might be remembering some media coverage, but not the science, which even in the 70s was more concerned with global warming than cooling: http://ams.allenpress.com/archive/1520-0477/89/9/pdf/i1520-0477-89-9-1325.pdf
123663. Ranger at 02:47 AM on 21 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        Wildfires, co2, carbon cycle. Just googled "wildfires co2". There sure seems to be a lot of concern, in some circles of the scientific community that wildfires are of concern to the amount of co2 in the atmosphere. I do not spend a lot of time on the computer but from what I did look at there seems to be a connection to different sorts of funding ie increased government funding for fire supression. We should not trust human nature and it lust for weath and power. When money and power are at stake, human beings are capable of great evils. With the amount of power and money at stake I am skeptical. Am I remembering right that in the 1970's greenhouse gasses were suppose to reflect the energy from the sun and caused a new ice age?
123664. Dikran Marsupial at 01:41 AM on 21 February 2010
        Did Phil Jones really say global warming ended in 1995?
        libertarianromanticideal @ 93 says: "In other words, Phil Jones (who strongly believes in the AGW hypothesis) thinks there is nothing unusual about the recent warming." No, that is not correct, there is nothing unusual about the magnitude of the trend, but that doesn't mean there is nothing unusual about the warming. For a start there is the fact that solar and volcanic forcing cannot explain the recent warming, unlike the other periods mentioned. This sort of thing is a good example of why scientists are on a hiding to nothing discussing science in the media. In this case Jones has answered every question in an admirably scientific manner, with no spin and happy to discuss the uncertainties involved. However that leaves room for his words to me manipulated, misquoted and misinterpreted. If on the other hand they use less scientific language that puts across the message, then they are criticized for undue certainty, and spin! "It is not statistically different from two earlier modern periods of warming. Since these warming periods were before the modern rise in CO2, greenhouse gases cannot have been responsible for those rises." However it would be a fallacy to suggest that just because the previous episodes of warming were not due to CO2 then the current one can't be due to CO2 either. "This raises the more important question: where is the warming anomaly?" Clearly displayed on temperature records, see e.g. woodfortrees.org "Jones' answer is -- there is NO unusual warming. There is no anomaly. There is nothing strange or out of the ordinary about the recent warming." He said nothing of the sort. "It is in no way distinguishable from earlier periods of warming, periods that we know were not due to rising CO2." There is a way to distinguish them, the previous episodes accompanied changes in solar and volcanic forcing. "There is nothing in the record that is in any way different from the centuries-long natural fluctuations in the global climate." That would only be true if we only had records of temperatures, and no records of volcanic and solar activity, and other sources of external forcing. "Jones also makes the interesting argument in the interview that the reason he believes that recent warming is anthropogenic (human-caused) is because climate models CANNOT replicate it. " That is not correct, he made no mention of models, he did mention chapter 9 of the IPCC report ("understanding and attributing climate change"), which does involve models, but is also based on a wide range of other evidence. "In other words, he seems to be admitting that he has absolutely no evidence at all, he just has the undeniable fact that our current crop of climate models can’t model the climate." Again, he said nothing of the sort. He did mention volcanic and solar forcing would suggest a cooling over the period considered, but you don't need a computer model to tell you that, just an understanding of the physics built into those models. If solar activity has not been increasing, you don't need to be Einstein to draw the conclusion it probably isn't the cause of rising temperatures. CO2 on the other hand is known to be a greenhouse gas, something that was known before electronic computers capable of running climate simulations were invented. "All this is just one climate scientist's assessment, but given Dr. Jones's stature, he can't easily be ignored." the irony! Phil gave a perfect example of how a scientist should answer questions, directly and without spin. If only the climate debate in general could be conducted in that manner!
123665. Riccardo at 01:34 AM on 21 February 2010
        On the reliability of the U.S. Surface Temperature Record
        rephrase the last sentence of second par.: Was the data upon which a scientist based its claims of any interest you'd have look for them before.
123666. Riccardo at 01:30 AM on 21 February 2010
        On the reliability of the U.S. Surface Temperature Record
        jpark, you're a bit late, John already posted an update on 28/1/2010 with the link to Watt's non-response, as always. As for UHI in London, it was not that difficult to find out yourself. I'd also suggest to not cast doubt and at the same time wash your hands with the (false?) premise "I respect what he says". Was it of any the data upon which a scientist based its claims you'd have look for them. Anyway, just to make your life easier, here's the first google search result i got. Just the first section on urbanization will give you an idea; should you need more details look at the scientific litterature, e.g. Jones et al. 2008, J. Geophys. Res. 113, D16122
123667. Marcus at 00:29 AM on 21 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        Here's another point though, GFW-the only case of true hardship I've heard of that was directly connected with the LIA was the loss of the Norse colony in Greenland-but that was mostly because the Norse were utterly inflexible in the face of changing conditions!
123668. Ned at 00:22 AM on 21 February 2010
        Did Phil Jones really say global warming ended in 1995?
        The causes of warming in the early 20th C are pretty well understood. Part of the warming then was also due to fossil fuels, but a significantly smaller part than modern warming. There was also a small contribution from increasing solar irradiance (as opposed to the past couple of decades when TSI has been decreasing) and from a temporary lack of volcanic forcings. I think most climate models handle the pre-1940s warming pretty well. It's rather silly to point to previous episodes of warming climate and say "See, it's warmed before, so the current warming must be natural!" That's an obvious logical fallacy, like saying that since some fires are caused by lightning no fires must be caused by arson. There's really no way to explain the past 3-4 decades of warming without CO2 and other GHGs. More importantly, unless we start moving towards a non-carbon-centric energy infrastructure, there's going to be a lot more warming over the 21st C.
123669. jpark at 00:05 AM on 21 February 2010
        On the reliability of the U.S. Surface Temperature Record
        More very helpful and thought provoking posts. My problem with the Menne et al paper is being confident in what they are measuring - Watts explanation has helped here (nice pictures!) - I am sure I posted the link before but maybe diogene has not seen it http://wattsupwiththat.com/2010/01/27/rumours-of-my-death-have-been-greatly-exaggerated/ RobM - thanks, but how does Jones know that? Is it just his opinion? London has changed hugely over the last 50, 100, 150 years. I respect what he says but what is it based on?
123670. suibhne at 00:02 AM on 21 February 2010
        Is CO2 a pollutant?
        doug_bostrom Presumably its a tungsten filament lamp from which heat cannot escape by any means other than conduction back along the electric wiring. The filament would continue increasing in temperature until evaporation of the tungsten compromised the reflectivity of the surface or until the filament melted. You probably think that the reflected IR would return to the metal. I think that that situation would be like someone trying to enter a football stadium as the crowds were exiting
123671. suibhne at 23:48 PM on 20 February 2010
        Is CO2 a pollutant?
        Philippe Chantreau carrot eater Lets see if we can agree on something carrot eater suggests a radiometer I think a thermopile would be more appropriate. Lets say the measuring instrument is accurately calibrated against a known and trusted source. What would it read if placed; A above the Stratosphere 342w/m2-agreed? B Just above the Earths surface 390w/m2 up + (168+324)w/m2down = 882w/m2-agreed? If you agree, do you not think this is rather odd? If you don't agree, explain your reasoning.
123672. Riccardo at 23:43 PM on 20 February 2010
        Did Phil Jones really say global warming ended in 1995?
        libertarianromanticideal, the fact that the 1910-1940 temperature increase is similar in magninute to the 1975- warming does not mean it is not unusual in the cause. Indeed, any climate scientist would aknowledge that a good part of the early 20th warming is not due to GHG. Your claim is highly misleading and you should not put your words in Jones mouth. You are making (unwillingly, i guess) the case for scientists not to talk with interviewers, a really bad thing to do. The language is different and words sometimes have different meaning; we need to put some effort into understanding it. Whenever we do not have direct access to a physical quantity (almost always indeed) we need to model the relation between that physical quantity and something we can measure. Even to measure temperature with a mercury thermometer we need to model thermal expansion and then measure a distance. Like it or not, physics IS a model of the real world. With this premise, a model is, for example, that the sun warms the earth through EM radiation and the average temperature of our planet is given (roughly) by its thermal equilibrium. A quite crude model, indeed. Then, of course, you might want to take all the other factors affecting earth's climate into account. By doing this we can confidently rule out natural contrubution to warming as the leading factor from about the '70s on. Do we now what the futture will be? No of course, no one can prove that, say, the sun will not abnormally increase or decrease its radiance overwhelming any anthropogenic contribution. But no one can prove the opposite as well. So we should, as humanity always did, stick to our "model of the real world", aka known physics.
123673. Ned at 23:39 PM on 20 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        Speaking of the LIA ... just to stir up the pot a bit, Bill Ruddiman has proposed the interesting hypothesis that land use changes following plague outbreaks resulted in a drawdown of CO2 from the atmosphere that could have largely explained the LIA. Much of Europe and Asia were partially depopulated by plague outbreaks from the 1300s to the 1600s (Europe lost somewhere between a quarter and half of its population). Likewise, the introduction of diseases into the Americas killed tens of millions in this hemisphere from the late 1500s to the 1800s. Ruddiman's argument is that the reduction in agriculture and the reversal of land clearing (re-expansion of forests, etc.) during the 1300s-1700s would have temporarily removed enough CO2 from the atmosphere to have initiated the LIA. It's an interesting argument, though I know many scientists are skeptical. But if there's an element of truth to this, it would help explain how the LIA could be a bit more severe than one would expect from the relatively small solar forcing alone.
123674. suibhne at 23:29 PM on 20 February 2010
        Is CO2 a pollutant?
        KR .....As to the back-reflection and what I understand of the GT arguments: More CO2 means more scattering and absorption/reemission events from CO2/IR interactions, more IR diverted from direct surface emission to off angles.... Have you thought about the absorbedIR in CO2 being thermalised ie present as intermolecular KE which can be tranferred by collision with say N2. I think that that is what happens to the bulk of the Earths radiation in the IR bands.
123675. Alexandre at 22:45 PM on 20 February 2010
        Visual depictions of CO2 levels and CO2 emissions
        RSVP, You're partly right. With increased CO2, the IR emmissions would be lower in its absorption band, but overall the IR would be the same given enough time. The problem is, temperature would have to raise to reach that equilibrium again. Here's a model kindly made available online by David Archer at the University of Chicago. Try this: - click "submit the calculation" to see the graph of the outgoing longwave radiation. That's the IR emitted by the planet. The big "bites" you see on the bell shaped curve are the greenhouse gases' absorption bands. - write down how much energy the Earth is emitting (Iout). - increase the CO2 on the left to, say, 750ppm, and submit the calculation again. You'll see the Iout has decreased. - Now increase the Ground temperature on the left and try to balance the Iout to its original amount. There. CO2 stopped some of the radiation to escape, total energy emitted got lower, the retained energy caused the temperature to rise, energy balance was restored. Did it get clearer? Please feel free to ask if it's not. I'm no expert, but it would be my pleasure to do my best to answer.
123676. libertarianromanticideal at 21:38 PM on 20 February 2010
        Did Phil Jones really say global warming ended in 1995?
        It seems the more interesting question the BBC asked Jones about the recent (i.e., 150 years) global record: Question: "Do you agree that according to the global temperature record used by the IPCC, the rates of global warming from 1860-1880, 1910-1940 and 1975-1998 were identical?" Jones: "An initial point to make is that in the responses to these questions I’ve assumed that when you talk about the global temperature record, you mean the record that combines the estimates from land regions with those from the marine regions of the world. CRU produces the land component, with the Met Office Hadley Centre producing the marine component. Temperature data for the period 1860-1880 are more uncertain, because of sparser coverage, than for later periods in the 20th Century. The 1860-1880 period is also only 21 years in length. As for the two periods 1910-40 and 1975-1998 the warming rates are not statistically significantly different (see numbers below). I have also included the trend over the period 1975 to 2009, which has a very similar trend to the period 1975-1998. So, in answer to the question, the warming rates for all 4 periods are similar and not statistically significantly different from each other." In other words, Phil Jones (who strongly believes in the AGW hypothesis) thinks there is nothing unusual about the recent warming. It is not statistically different from two earlier modern periods of warming. Since these warming periods were before the modern rise in CO2, greenhouse gases cannot have been responsible for those rises. This raises the more important question: where is the warming anomaly? Jones' answer is -- there is NO unusual warming. There is no anomaly. There is nothing strange or out of the ordinary about the recent warming. It is in no way distinguishable from earlier periods of warming, periods that we know were not due to rising CO2. There is nothing in the record that is in any way different from the centuries-long natural fluctuations in the global climate. SOURCES: CET: http://hadobs.metoffice.com/hadcet/data/download.html ARMAGH: http://www.arm.ac.uk/preprints/445.pdf ADJUSTMENTS TO THE CET: http://www.anenglishmanscastle.com/archives/004482.html JONES BBC INTERVIEW: http://news.bbc.co.uk/2/hi/science/nature/8511670.stm Jones also makes the interesting argument in the interview that the reason he believes that recent warming is anthropogenic (human-caused) is because climate models CANNOT replicate it. In other words, he seems to be admitting that he has absolutely no evidence at all, he just has the undeniable fact that our current crop of climate models can’t model the climate. All this is just one climate scientist's assessment, but given Dr. Jones's stature, he can't easily be ignored.
123677. Riccardo at 21:23 PM on 20 February 2010
        Visual depictions of CO2 levels and CO2 emissions
        RSVP, indeed the atmospheric greenhouse gas effect is often (popularly) described as a blanket. Below the blanket it will definitely be warmer.
123678. RSVP at 20:42 PM on 20 February 2010
        Visual depictions of CO2 levels and CO2 emissions
        Chris G I dont have a problem with the word "rattle" for energy that just sits there all day. But in this case it doesnt. It has more "initiative" than that, and will tend with a higher probability to migrate to where there is less. I guess that was my point.
123679. RSVP at 20:36 PM on 20 February 2010
        Visual depictions of CO2 levels and CO2 emissions
        Ned, Chris G, Alexandre What is all this about straw man, DK effect, saturation argument, etc. Why not give straightforward answers? Like exactly how much IR would attenuate over a few meters? (if you happen to know). Any energy imparted on the atmosphere should raise the temperature of the atmosphere. Fine. But isnt this just another arbitrary launch pad for cooling the Earth? I would prefer not to use analogies, but this one seems very illustrative.... I have an electric radiator for heating my room. I throw a blanket over it. (no danger of fire assumed) Perhaps during one hour I notice the heat isnt getting to me as before, but after a while, it makes no difference as the blanket comes up to temperature. The blanket does not impede the net heat flow delivered to the room. As they say, "Watts is Watts." The analogy refers to the original question as to whether more or less IR should be detected by satellites. Based on the blanket analogy, it looks in any case that IR levels might drop, but overall, they should stay the same.
123680. GFW at 19:43 PM on 20 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        To follow up on Marcus's answer to HR: in addition to what he said, the solar forcing (slightly lower TSI) during the LIA was also reinforced by higher than average volcanic activity(*). Those two effects were global. It is also suspected, though far from proven, that ocean currents slowed down, strengthening the cooling in Europe and possibly a couple of other regions. So that's how the LIA was cold enough to be a hardship. (*) Volcanoes are a cooling forcing on human timescales because they inject reflective aerosols into the atmosphere. For example Mt. Pinatubo (June 1991): In 1992 and 1993, the average temperature in the Northern Hemisphere was reduced 0.5 to 0.6°C and the entire planet was cooled 0.4 to 0.5°C. The maximum reduction in global temperature occurred in August 1992 with a reduction of 0.73°C. However not much effect remained after 5 years or so. On really long timescales, large scale volcanism can warm the planet with CO2 emissions that outlast the aerosols by orders of magnitude. It is thought that there was a "snowball earth" scenario in the period 650 and 750 million years ago, and that volcanic CO2 was what ended the snowball state.
123681. jimrhiz at 17:57 PM on 20 February 2010
        It's cooling
        Great site and page thank you! One very small cavil ... "Since 1970, the Earth's heat content has been rising at a rate of 6 x 10^21 Joules per year. In more meaningful terms, the planet has been accumulating energy at a rate of 190,260 GigaWatts. Considering a typical nuclear power plant has an output of 1 GigaWatt, imagine 190,000 nuclear power plants pouring their energy output directly into our oceans." The value 6 x 10^21 Joules per year has one significant digit (similar in accuracy to other figures one the page, like 0.77 ± 0.11). So it gives a misleading idea of accuracy to say "190,260 GigaWatts", with 5 significant digits. It would be better to stick to one significant digit, and conclude: "the planet has been accumulating energy at a rate of about 200,000 GigaWatts" and then also adjust the nuclear power plan count accordingly (bearing mind as well that Barry Brook's comment 5 above challenged the 1GW per plant estimate).
123682. Marcus at 17:51 PM on 20 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        @Ranger. Its called The Carbon Cycle for a reason. All the carbon which goes out is accounted for by Carbon sinks on land & sea (plants, soils, phytoplankton, direct ocean absorption). The only carbon not directly accounted for, IIRC, is from volcanoes & limestone erosion-both of which generate a tiny fraction of the CO2 generated by burning fossil fuels. The reason burning fossil fuels has such a massive impact on atmospheric CO2 levels is because they're fossilized trees which grew in an extremely CO2 rich (3000ppm +) environment several hundred million years ago (the aptly named Carboniferous Era). All plant & animal life alive today has existed in the "carbon constrained" environment of the Quaternary period, where CO2 levels have never exceeded 290ppm (they are now close to 400ppm). Hope that makes sense.
123683. Marcus at 17:46 PM on 20 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        Humanity Rules. What you need to remember is that this modeling covers only 100 years. The Little Ice Age occurred over a multi-century time period (over 300 years IIRC). That's a long time for the negative energy imbalance to build up and cause *significant* cooling. That cooling event was offset by the return to "normal" TSI over the 250 year period up to 1950 (which gave a warming trend of around +0.06 degrees per decade). Since 1950, the sun has either been stable, or in a mild decline, yet warming trends are even *faster* than the previous 250 years.
123684. Tom Dayton at 16:44 PM on 20 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        Ranger, fossil fuels are highly concentrated forms of plant material. You'd have to burn a huge amount of grass, wood, or any other plant material, to get the same energy as a tiny amount of fossil fuel. That's a major reason we use fossil fuel. Think of fossil fuel as distilled plants. That distillation concentrates not just the energy from the plants, but also the carbon. In fact, the concentrated carbon is that concentrated energy, in the form of the chemical bonds that the carbon is involved in. So when a small amount of fossil fuel is burned, it releases both the huge amount of energy of the huge amount of plants, and as an inevitable result the correspondingly huge amount of carbon.
123685. GFW at 16:21 PM on 20 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        Ranger, think of it this way. Plants grow. They can be burnt, be eaten, or fall down and rot. All of those result in the carbon returning to the atmosphere ... to feed more plants. Before significant human intervention, the total amount of carbon in plants would remain roughly the same (different areas burn, suffer locust plagues, or whatever each year) on average over years. Thus the total amount of carbon in the air was also roughly the same over years. Even significant human agriculture and other land use changes have only had a relatively small effect on the total amount of carbon in plants at any given moment, although we may be cycling it in and out of plants faster. The thing that's causing the major change in atmospheric carbon dioxide is that we are taking carbon that was locked away for tens of millions of years as fossil fuels and burning those. The following article gives a good overview of the carbon cycle and particularly how much carbon is where (in plants, in the soil, in the air, in the ocean, etc.) That's table 1. http://www.eoearth.org/article/Carbon_cycle One part of the article is missing an important point though. The part that talks about "missing carbon" is wrong so far as I can tell, because there is no mention of ocean acidification. Currently, when humans add carbon to the biosphere by burning fossil fuels, it gets divided roughly in half - one half for the air, and one half for the oceans. Unfortunately this has the effect of reducing the pH of the oceans. This has now been measured as an average drop from ph 8.2 to 8.1. That may not seem like much, but if we keep going, it could cause mass extinctions.
123686. pmheideman at 15:51 PM on 20 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        "So seems to me that historic fires produced as much co2 back then as burning fossil fuels do today. " Seems to you based on what, your guestimation? In fact, we know how much CO2 was in the atmosphere hundreds of years ago, and it was quite a bit less than there was today (see graph here http://www.skepticalscience.com/The-Dunning-Kruger-effect-and-the-climate-debate.html). If your theory that anthropogenic emissions were merely replacing those of wildfires, we wouldn't see the massive spike that we do. Beyond your folksy wisdom, there is no evidence to support the scenario you construct.
123687. Ranger at 14:42 PM on 20 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        Ned , yes that is my question, but I still don't get it. I guess one could do the research to find out how much land burned every decade, say hundreds of years ago versus the tiny tiny fraction of land that burns today. So seems to me that historic fires produced as much co2 back then as burning fossil fuels do today. Plus if you consider that tonage wise, more cultivated crops produce much more plant matter than short grass praires would have. These crops like corn, milo, soybeans, Sudan Haygrazer.... would recycle much more carbon that grass does, plus the uncultivated land is still covered with plant life. I have spent more time outdoors horseback than most people have spent in their beds. I realize that since the the late 1980's the climate has got warmer. But I also see that in the last few years I have been colder. I also like to read, mostly History. History is full of antedotes down thru the centuries of the earth's tempature being hotter then colder. Thanks Albany, Texas
123688. Ned at 14:14 PM on 20 February 2010
        Visual depictions of CO2 levels and CO2 emissions
        RSVP writes: When I made that remark #18, I was attempting to let Alexandre consider what he told theendisfar, taking his remark it to its logical conclusion, and so point out an untruth. Not trying to be rude or anything, but Alexandre has a much better understanding of this than you do. Thus, your tone here smacks a bit of the whole D-K effect.
123689. Doug Bostrom at 14:10 PM on 20 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        Not to be the slightest bit pejorative, but Ranger has brought the brushfire matter up several times of late here, on several threads, and he has always received the same basic response without apparently acknowledging these answers. Ranger, would you mind responding to Ned's answer, just so we know you're reading the answers you're eliciting?
123690. Ned at 14:06 PM on 20 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        Ranger writes: Why did'nt all that co2 belched into the atmosphere in past history cause global warming? As I understand it, you're pointing out that in the days before fire suppression (and still occasionally today) there were big wildfires in many places. Presumably those put a lot of CO2 into the atmosphere, right? So why didn't that cause global warming? If you think about it, you can't keep having fires unless stuff grows back between the fires to create the fuel load for ... more fires. In other words, in a pre-fossil-fuel time, the carbon added to the atmosphere by fires was then removed from the atmosphere by the regrowth of plants. What's different today is that instead of just cycling the same carbon through the system over and over again, we're injecting into the atmosphere a heck of a lot of fossil carbon that was laid down over a period of tens of millions of years.
123691. Ned at 13:54 PM on 20 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        HumanityRules writes: I also have another question. The implication in the articlet is that the LIA was a regional phenomenon. As far as I'm aware the sun shines down on the whole of the planet. How can it's effect be regional? And if there is a regional explanation how can any other forcing dodge this regionalism? Actually, due to the nature of feedbacks and the transfers of energy within the climate system, even a uniform global forcing won't produce uniform regional impacts. Thus, for example, anthropogenic CO2 becomes well-mixed in the atmosphere within a few years but the warming that results from it is very unevenly distributed (e.g., more warming in the arctic, and in the N hemisphere, and over land, etc.) Right?
123692. Ranger at 13:51 PM on 20 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        Ok, I just a West Texas cowpuncher and have not had my question answered by you scientific guys. My question is at the end. For thousands of years wildfires burned up ba-zillions of acers grassland, forrest and brush annually. Where I live in West Texas we had a little grass fire one April day2006, that burned over a million acres and killed 12 people and thousands of beef cattle, some horses and untold wildlife. That was with scores of City Fire Depts, Rural Fire Depts, US Forrest Service, Ranch firefighting rigs, Interstate Highways, State Highways, County Roads, large parcles of cultivated land; all trying to frustrae and stop this fire. Before White European Settlement, fires like this kept our part of the world praires. Brush, TREES, Prickly Pear now cover the land. Once home to the Antelope and Buffalo now prime Whitetail Deer Habitat. Why did'nt all that co2 belched into the atmosphere in past history cause global warming?
123693. Ned at 13:40 PM on 20 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        oracle2world writes: "What would happen if the sun fell to Maunder Minimum levels?" It would get cold. Any questions? You didn't actually read the post, did you? The whole point of this thread is that it probably wouldn't get particularly cold. As John said (in a turn of phrase that I find amusing) "the effect of a Maunder Minimum on global temperature is minimal".
123694. HumanityRules at 13:08 PM on 20 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        Tony Noerpel #19 Surely the physics are the same in 1700's and 2100's. If a grand minimum produces a 0.09-0.3oC drop in 2100 then it does the same in 1700 no matter what the base position you are starting at. Given that, my question is, can the 1700's be recognised as a cold period of history with that level of change? If not then we have to get rid of the LIA from history. This just appears a circular argument. Having assumed in the model that solar has a negligible effect the scientist asks the question what is the effect of a Grand Minimum. No surprise when the answer comes back negligible. I also have another question. The implication in the articlet is that the LIA was a regional phenomenon. As far as I'm aware the sun shines down on the whole of the planet. How can it's effect be regional? And if there is a regional explanation how can any other forcing dodge this regionalism?
123695. oracle2world at 12:46 PM on 20 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        "What would happen if the sun fell to Maunder Minimum levels?" It would get cold. Any questions?
123696. Gaia_Dee at 11:28 AM on 20 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        The oceans are huge heat reserves, aren't they? It is ocean currents, more than the air, that affects whole seasons of weather for any part of the world. Currents keep Europe warmer than it should be for it's latitude. The El Nino phenomenon is what has determined the cold weather this winter. All of the above are considered "weather" which is not the same as "climate". It is probably better that we not even use the word "climate", but to refer to, instead, the mean temperature of the earth's ocean's rising and the increasing reflectivity of the atmosphere. I think using the word "climate" has a weather connotation to the common ear. The danger we are facing is our increasing the heat energy we are storing inside our atmosphere and ocean. The more energy that is added, like to any closed system, the more changeable the currents and air streams are; the more ice melts and sea levels rise, the more turmoil and swell differences in the oceans, and the more variety in storm characteristics. All of these mean changes in where the rain falls, flooding some, making others into deserts, turning rainforests into savannas, changing what we can grow where, et cetera, et cetera. Here we will have multiple climate changes all over. If we look at the planet as a big system that is keeping more heat than it is giving up, then one can better imagine, based on high school level experiments in thermodynamics, what this phenomenon means for humanity. The "icing" on this terrible cake is the ocean becoming more acidic, which is certain to cause extinctions of vulnerable species (like our food fish). All this because a few "deniers" say that the laws of physics don't apply to the earth? that we "can't change" from coal and oil to nuclear, wind, geothermal, and solar? Considering that, if Edison had his way, we would have been all driving electric cars already. If Three Mile Island hadn't scared people away from nuclear, just think of where we would be in addressing this issue. If Carter had gotten his gas tax applied as the prices for gas were dropping, our cars would not be the monsters they are today.
123697. Philippe Chantreau at 10:38 AM on 20 February 2010
        Is CO2 a pollutant?
        The diagram makes sense, you don't understand it. Net outgoing IR is 390-324= 66. Thermals and evaporation 78+24=102 Total net outflow from surface: 102+66=168. Now can you clarify what you were trying to say with your double sided solar panel idea?
123698. KR at 09:58 AM on 20 February 2010
        Is CO2 a pollutant?
        On the CO2 absorption/insulation: More scatter events in the atmosphere due to higher CO2 concentrations, in addition to back-reflection to the ground, also increase atmospheric path length. This increases chances of IR absorption by other gases -> heating, as well as CO2 energy increase due to non-radiative heating of the CO2, which I believe (I work with fluorescent dye systems) occurs as a low probability event on IR absorption.
123699. carrot eater at 09:54 AM on 20 February 2010
        Is CO2 a pollutant?
        You guys have more patience than I do. suibhne "Even on one side it does not add up 342 solar from Sun On Earth surface 168 solar + 324 back radiation" What does this even mean? On the diagram, I can count three places to draw an envelope for checking the First Law. One is the earth's surface, and it checks. Second is the atmosphere, and it checks. Last is the top of the atmosphere, and it checks. Nowhere is there net heat transfer from a colder to a warmer body. Nowhere. And 'heat' is perfectly acceptable for referring to transfers of thermal energy, by either radiation, convection or conduction. Everything checks out thermodynamically, suibhne. Perhaps you should invest in a radiometer. One that covers longwave IR, mind.
123700. KR at 09:45 AM on 20 February 2010
        Is CO2 a pollutant?
        suibhne: The Kiehl-Trenberth graphic is an excellent summary of a balanced energy system. Using their numbers for illustration, the input energy from the sun (342-107, or 235 watt/m^2) is balanced by the output (165+30+40 = 235 watt/m^2). Without atmosphere, the surface would directly radiate 235 w/m2 in balance, but the atmosphere insulates by radiating energy (324) back to the surface, allowing a considerably higher surface temperature that radiates ~390 plus thermals + evaporation heat. Increasing back reflection (above 324) with higher CO2 levels decreases the energy emitted to space - energy accumulates (heating the surface and atmosphere) until radiated energy increases from 390/surface and 165/atmospheric to some higher level that pushes a total of 235 out past the insulation, and the system reaches balance again. Note that this does not include potential positive/negative feedback mechanisms - those are outside the current discussion. As to the back-reflection and what I understand of the GT arguments: More CO2 means more scattering and absorption/reemission events from CO2/IR interactions, more IR diverted from direct surface emission to off angles, which means more heads back to earth (total scatter angle -> down). This is a mass effect; single photon tracing CAN be used to show the same thing IF you sum up the probabilities of CO2 interception and radiation scattering angles - choosing a single case where a photon escapes doesn't say anything about mass effects.

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