Recent Comments

Prev  2467  2468  2469  2470  2471  2472  2473  2474  2475  2476  2477  2478  2479  2480  2481  2482  Next

Comments 123701 to 123750:

123701. Pierre-Normand at 16:17 PM on 21 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        "The research was done on the Metolius River Watershed in the central Oregon Cascade Range, where about one-third – or 100,000 acres – of the area burned in four large fires in 2002-03. Although some previous studies assumed that 30 percent of the mass of living trees was consumed during forest fires, this study found that only 1-3 percent was consumed." http://www.newwest.net/...impacts_often_overestima/
123702. Ned at 14:43 PM on 21 February 2010
        Water vapor is the most powerful greenhouse gas
        A year ago, Mizimi wrote: A few sums ....various sources give our annual energy usage from FF as around 14 terawatts. That's almost certainly the power directly associated with combustion of fossil fuels, not the radiative forcing from the CO2 produced by that combustion. But, more or less coincidentally, the annual increase in radiative forcing is probably pretty close to that 14 terawatts worldwide. (Based on these data from NOAA, it looks like the annual increase is 0.03 watts/m2 which works out to about 1.5E13 watts over the planet as a whole. Mizimi continues: Looking around the Australian Bureau of Statistics gives the following population figures.... People 21 million Horses 400,000 Kangaroos 23 million Camels 400,000 Cattle (dairy and beef) 26 million Sheep 20 million Rabbits 250 million Simple maths - multiplying numbers by the basal metabolic rate at rest of each species gives a daily heat emission of 315 x 10E9 watts or 114 x 10E12 watts per annum. Whoa, do you understand the meaning of the word "watt," Mizimi? A basal metabolism of 1 watt is 1 watt, whether you measure it over a period of days, weeks, years, or millennia. If you're going to convert the metabolic data to watt-years, you need to do the same conversion for the radiative forcing! Let's redo those calculations. I can't find actual data on the metabolic rates of kangaroos etc., but I see that sheep are about 50 watts, cattle about 330, and humans about 78. Using Mizimi's population figures, that works out to a total basal metabolism of 1.1E10 watts, several orders of magnitude less than the figure that Mizimi quotes. I don't think adding in the kangaroos and rabbits would make up the difference :-) The annual increase in radiative forcing from greenhouse gases is 1360 times larger than that. In other words, every 6.4 hours we're adding a radiative forcing to the climate system that's approximately equal to the combined metabolism of all the people, cattle, and sheep in Australia. Two caveats in closing: (1) If that seems like a silly comparison, blame Mizimi not me. (2) Apologies for responding a year late ... but Mizimi's original post was so severely erroneous and had gone uncorrected for so long that I thought it would be good to set the record straight.
123703. lepton at 14:23 PM on 21 February 2010
        Water vapor is the most powerful greenhouse gas
        Ned at 13:23 PM on 21 February, 2010 writes: "More than anything else, it was studies of the process of CO2 uptake by the oceans that set off alarm bells about global warming in the 1970s and early 1980s. Until then people thought most of the CO2 we emit would end up in the oceans. When it became clear that this would take a long, long time to happen, people began to realize that this is a big problem that we're facing." Thank you for valuable references. However - as a physicist (not climatologist) - I can hardly understand why the time scale of the process of the CO2 reaching equlibrium between atmosphere and ocean concentrations process might be any different from that of WV evaporation rate due to ocean-air temperature differences. Both processes are based on the same molecular mechanisms. Perhaps the culprit is the ocean surface layer - warmer than the bulk, so evaporating more willingly, at the same time accepting less CO2?. Might it be that the significant factor is the mixing of ocean? Both on surface by waves and in bulk by currents?
123704. lepton at 13:39 PM on 21 February 2010
        Water vapor is the most powerful greenhouse gas
        to villar at 20:21 PM on 2 December, 2009 Any positive feedback is the source of instability, by definition. I do regret that so many climatologists have so minimal knowledge of process control. Not every positive feedback blows a sytem up. It can also make it oscillate, like in simple systems with phase delay. In climate - an obvious complex set of interwoven processes - a positive feedback like VW induced GH effect - generally will drive conditions to the point when other (up to then dormant) processes will activate, possibly turning on some negative feedback. The very fact that Earth's ecosphere still exist after so many evidences of past climate extremities proves that (regardless of any positive feedback) our globe can always find equilibrium (if only local).
123705. Ned at 13:23 PM on 21 February 2010
        Water vapor is the most powerful greenhouse gas
        lepton writes: Antropogenic CO2 will in consequence mostly go to the oceans, and again - taking into account their far greater capacity then that of atmosphere - it should not accumulate to significant long-term levels in atmosphere making its impact on climate transient. Well, that's true, as long as you can accept a timescale of tens of thousands of years as "transient." Yes, most of the CO2 we add to the atmosphere will end up in the ocean but given the thinness of the mixed layer and the slow rate of movement from the atmosphere to the mixed layer to the deep ocean, that will take a long time to happen. In the meantime, atmospheric CO2 will almost certainly exceed 2X preindustrial levels, if not 3X. How than can be explained the rising concentrations of CO2 in the air - observational fact beyond doubt? Either it is really of antropogenic origin and then it seems to be a small problem (as it is on its way into ocean) or - CO2 is released by the warming ocean (for which I - and perhaps we - miss information), a process that can be of far more dangerous consequences. Actually, it's quite clear that CO2 is going from fossil fuels to the atmosphere to the ocean, not the opposite direction. See, e.g., the following papers: Takahashi et al. 2009. Climatological mean and decadal change in surface ocean pCO2, and net sea–air CO2 flux over the global oceans. Deep Sea Research Part II: Topical Studies in Oceanography, Volume 56, Issues 8-10, April 2009, Pages 554-577. Sabine, et al. 2004. The Oceanic Sink for Anthropogenic CO2. Science, Vol. 305. no. 5682, pp. 367 – 371. Yes, as it warms the ocean can hold less CO2, but CO2 is rising faster in the atmosphere, so there's a net flux from the atmosphere to the ocean. More than anything else, it was studies of the process of CO2 uptake by the oceans that set off alarm bells about global warming in the 1970s and early 1980s. Until then people thought most of the CO2 we emit would end up in the oceans. When it became clear that this would take a long, long time to happen, people began to realize that this is a big problem that we're facing.
123706. Leo G at 13:13 PM on 21 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        John, just read that you are a solar physicist, Nice! One of your peers, Dr. Svalgaard, is quite adamant that the change in TSI is so minute that it has no discernable relationship to cooling or warming of the planet. He even points out that at the "coldest" point of the LIA, the sun was actually on its active side! I would love to get your thoughts on this. By the way, if I addressed you as Dr. Cooke, would that be right? :)
        Response: It wouldn't be correct, I'm not a Dr (and there's no e in my surname :- ) and the Guardian was incorrect in labelling me a solar physicist (which unfortunately has spread throughout the blogosphere). I did a physics degree and majored in solar physics in my post grad honours year but I am not a professional scientist now. I'm pretty clear about this on the About Us page.
        
        I haven't looked too much into Svalgaard's work but I have actually downloaded an Excel collection of TSI reconstructions of his website - it shows a number of reconstructions revealing his version is somewhat of an outlier compared to other works.
123707. Leo G at 13:06 PM on 21 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        One other thing Ranger, remember that forest/grassland fires only have about 40-70% complete combustion. As opposed to say a good wood burning stove which can get to the 85% area. In a perfectly controlled burn scenario, most of the oxygen would combine with the carbon to form CO2. Natures own fertilizer. But in forest/grass fires, the combustion process is affected by variables that produce not only CO2 but CO. As well as NOx's, Butyls, etc. Our internal combustion technology attains a much higher percentage of complete combustion, then the open fires on ranges. Therefore they paradoxically produce more CO2! Also, perhaps the biggest thing that needs to be pointed out is that forest/grass fires are very "messy". They tend to throw a lot of soot and aresols high into the atmosphere. Now if the soot happens to fall on ice or snow, we can have a strong warming effect. But if it falls on plant covered land, we have a fertilizing effect. But the aresols that have been pushed miles high into the atmosphere will and do act as reflectors of the incoming energy from the sun. Thus from these fires, we may actually get a regional net cooling effect over the next few years. Right now in Canada, B.C. has the highest output of GHG's of any province in the country. This is from the rotting of all the pine beetle killed trees. All that bacteria that is turning the trees back to soil and energy are farting a lot. It probably would be better for the climate, from a warming/cooling viewpoint, to have let these forests burn 20 years ago. But you know, hindsight is 20/20.....
123708. lepton at 12:17 PM on 21 February 2010
        Water vapor is the most powerful greenhouse gas
        If I can comment the discussion of Chris G and Mizimi: It is very interesting and I am amazed by the level of details being analyzed. Nonetheless my impression is that keeping an eye (and mind) focused on details prevents sometimes from noticing more relevant obvious facts which can render the details insignificant. The neglected factor seem to be the stabilising impact of oceans. While it is true that raising temperature of atmosphere increases its capacity to hold more WV thus raising its potential for more efficient GH effect - to fill this capacity requires liquid water reservoirs of elevated temperature. Primary source of globe's VW are oceans, whose heat capacity is several orders of magnitude higher than that of atmosphere and it would take millenia for the air to warm them up. Over the lands water sources are less massive and thus can more readily make use of raising evaporation conditions. However - taking into account high mobility of atmosphere and effective mixing - the warming effect will be diluted (with the probable net effect being enhanced removal of moisture from lands to oceans). As to the C02 - again it is the temperature of the oceans that determines water-air equilibrium concentrations. Antropogenic CO2 will in consequence mostly go to the oceans, and again - taking into account their far greater capacity then that of atmosphere - it should not accumulate to significant long-term levels in atmosphere making its impact on climate transient. How than can be explained the rising concentrations of CO2 in the air - observational fact beyond doubt? Either it is really of antropogenic origin and then it seems to be a small problem (as it is on its way into ocean) or - CO2 is released by the warming ocean (for which I - and perhaps we - miss information), a process that can be of far more dangerous consequences.
123709. RedFishBlueFish at 10:17 AM on 21 February 2010
        There's no empirical evidence
        "Gradually the models seem to agree more and more with each other, which is hardly surprising since consensus is the key to progress here: you get your report published if it gives similar results as all the other reports, and if you don't agree you will be an outcast in the world of climate science." Actually Nobels, and other types of recognition, are not awarded for confirming previous work. Another interpretation of why the models are converging, is that they are converging on a demonstrable phenomenon - much as models of the structure of matter converged on the atomic, vs continuous, nature of matter at the end of the 19th century.
123710. Peter Hogarth at 09:36 AM on 21 February 2010
        Visual depictions of CO2 levels and CO2 emissions
        Here's a leading question which may well display my ignorance, but please answer (skeptically or otherwise!) if this is your area of expertise. Assuming a significant fraction of the global CO2 sink is (for example) the high Northern latitude forests and vegetation in the growing season, and a significant Global Methane source is high Northern latitude wetlands in Summer/Autumn, then how much of the Anthropogenic Carbon drawn down as CO2 then makes its way back into the atmosphere as CH4 through decay of some of that "extra" growth, - with potentially 21 times the Greenhouse effect??? I'm not sure if this carbon rectification/GHG amplification idea is original or even significant, but it would be interesting to run the math...
123711. Doug Bostrom at 08:19 AM on 21 February 2010
        There's no empirical evidence
        Argus, thanks for reading those. You and I differ on our interpretations of outcomes of the narrative, particularly as regards conformist thinking infecting science, but I'm really glad you took the time to grind through it all. As to email, reputations and the like, physics and mathematics are oblivious to such things; inconsistencies and errors will inevitably reveal themselves if such there are and that process will not take place via newspaper articles.
123712. joseph449008 at 08:12 AM on 21 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        

        the authors conclude the most likely impact of a Maunder Minimum by 2100 would be a decrease in global temperature of 0.1°C

        I estimated this once based on the solar irradiance reconstruction from Lean (2000). What I came up with is 0.2°C. It's not very difficult. Assume emissivity and albedo are constant. If this is the case, absolute temperature is directly proportional to solar irradiance to the 1/4th power.
123713. Argus at 08:01 AM on 21 February 2010
        There's no empirical evidence
        Doug, thanks for the interesting links to essays on climate model history! I have read it all, and learned that modelling has been a challenging area for more than 100 years. Also that the models have all been very different from each other, full of flaws and weaknesses, and afflicted with serious simplifications that diminished their value. Gradually the models seem to agree more and more with each other, which is hardly surprising since consensus is the key to progress here: you get your report published if it gives similar results as all the other reports, and if you don't agree you will be an outcast in the world of climate science. I am not much comforted, though. Climatologists don't have a very good reputation anymore, after recent scandals with emails, and the glacier bluff. I predict more awkward revelations to be made in times to come.
123714. carrot eater at 07:57 AM on 21 February 2010
        Is CO2 a pollutant?
        To clarify: the map on the last page of http://www.sciencemag.org/cgi/data/308/5723/850/DC1/2 is estimated from satellite data, but from the preceding figures you can see that the calculations from satellite data match up very nicely with actual measurements at the surface.
123715. GSW at 07:52 AM on 21 February 2010
        It's cooling
        nice article, very clear what you are getting at. Question: Don't the models take the Oceans (as a heat sink) into account? If so, how have they got it so wrong?
123716. carrot eater at 07:52 AM on 21 February 2010
        Is CO2 a pollutant?
        suibhne: And on the last page of this, you can see the solar radiation that reaches the surface, per area. As you might expect, this varies with latitude. http://www.sciencemag.org/cgi/data/308/5723/850/DC1/2 Let's get back to basics, suibhne. Say you've got one wall at 25 C. Directly facing it is another wall, at 50 C. Behind each wall is some mechanism keeping the temperature of the wall perfectly constant. There is a perfect vacuum in the gap between the two walls. Both walls are perfect blackbodies. What are the energy flows?
123717. carrot eater at 07:33 AM on 21 February 2010
        Is CO2 a pollutant?
        suibhne: Here are actual measurements of longwave IR radiation headed downwards towards the surface, measured at the surface. Figures 1 to 4. You can see the cartoon is correct in its order of magnitude. The actual numbers vary, based on where on earth you are, the humidity and clouds overhead, etc. http://www.arm.gov/publications/proceedings/conf12/extended_abs/morcrette-jj.pdf So yes, the atmosphere sends a lot of IR down, and you can measure it.
123718. petewsh61 at 07:26 AM on 21 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        Ranger #37 The big concern with wildfires is those in the boreal forests and to some extent tropical forests. When burn rates outpace the rate of regrowth of forest, that CO2 stays in the atmosphere and further contributes to warming. This sets up a positive feedback that further warms and drys the forests and increases the burn rate and CO2 release. The 1970's reports on global cooling had nothing to do with the effect of greenhouse gases. In addition, there was very little scientific support for the idea. The media on the other hand treated it as a big story - scientists not in the least.
123719. petewsh61 at 07:20 AM on 21 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        Ranger reasonably asks "Why did'nt all that co2 belched into the atmosphere in past history cause global warming?" 1) The amount of Co2 belched by those grass lands burning is a very small fraction of what we are belching by burning fossil fuels. 2) Those grasslands typically grow back (grasses are adapted to fires by the ability to grow from the base of the plant) - and when they do grow back they absorb just about the same amount of CO2 they belched out when they burned.
123720. Tom Dayton at 07:12 AM on 21 February 2010
        On the reliability of the U.S. Surface Temperature Record
        jpark, please notice that some comments by people responding to you also have been deleted, for similar reasons. John Cook is trying to keep the tone of his site well above the level of most other sites. Otherwise the slope would be too slippery, and an ongoing discussion that was "allowed" to be "slightly" in violation would "suddenly" and "arbitrarily" have some comments removed, with the resulting appearance of bias by the moderator. ("Why did you delete my comment and not so-and-so's?") One of the things that is prohibited is attribution of ill motives to people--not just to people posting comments, but to scientists who've written journal articles, and anybody else. I've certainly had my own comments deleted--even when they were funny. Even a single violation in an otherwise excellent comment will get the entire comment deleted. That's too bad, but I imagine John does not have time (let alone the patience) to edit out just the offending portion. If you keep a copy of your comment before submitting it, you can later resubmit it without the offending part.
123721. petewsh61 at 07:07 AM on 21 February 2010
        Skeptical Science housekeeping: iPhone app, comments and translations
        1) The large table in "Global warming is good" is cropped on one side. I can move the table over to the left, but then I can't see text on the left. One way to solve this would be to change orientation of text window when I tilt my iTouch sideways. 2) Is there a way to increase text size more then just to fill the frame. Resize-able text would be nice. Overall a great app to have at hand.
123722. 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.
123723. 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.
123724. 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?
123725. 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.
123726. 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.
123727. 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.
123728. 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.
123729. 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.
123730. 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?
123731. 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?
123732. 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
123733. 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
123734. 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?
123735. 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!
123736. 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.
123737. 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
123738. 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!
123739. 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.
123740. 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?
123741. 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
123742. 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.
123743. 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.
123744. 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.
123745. 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.
123746. 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.
123747. 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.
123748. 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.
123749. 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.
123750. 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.

Prev  2467  2468  2469  2470  2471  2472  2473  2474  2475  2476  2477  2478  2479  2480  2481  2482  Next