Climate Science Glossary

Term Lookup

Enter a term in the search box to find its definition.

Settings

Use the controls in the far right panel to increase or decrease the number of terms automatically displayed (or to completely turn that feature off).

Term Lookup

Settings

All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Home Arguments Software Resources Comments The Consensus Project Translations About Support

Bluesky Facebook LinkedIn Mastodon MeWe

Twitter YouTube RSS Posts RSS Comments Email Subscribe


Climate's changed before
It's the sun
It's not bad
There is no consensus
It's cooling
Models are unreliable
Temp record is unreliable
Animals and plants can adapt
It hasn't warmed since 1998
Antarctica is gaining ice
View All Arguments...



Username
Password
New? Register here
Forgot your password?

Latest Posts

Archives

Recent Comments

Prev  2036  2037  2038  2039  2040  2041  2042  2043  2044  2045  2046  2047  2048  2049  2050  2051  Next

Comments 102151 to 102200:

  1. A Cloudy Outlook for Low Climate Sensitivity
    Camburn wrote : "There is really no evidence one way or another as of yet as to cloud feedback. There are suggestions going in both directions." Except there is far more evidence going one way than the other, as you can see at AGW OBSERVER : Papers on Cloud Feedback observations Papers on the Iris Hypothesis of Lindzen Anti-AGW papers debunked (including Spencer) But so-called skeptics prefer to stick with the lone voices, don't they ? Why IS that ?
  2. A Cloudy Outlook for Low Climate Sensitivity
    Daniel Bailey@15: 1. We all know that GCMs do not handle the h20 cycle well at all. 2. When I read a paper, I read the error bars and the certainty of the paper. 3. There are papers on both sides of the cloud sensativity scenerio. Non of the papers show, with a credible certainty, that clouds are well modeled yet. Hence the results are uncertain. Show me this evidence that is verifiable and not modeled, but observed. A small area of the world is a start, but we all know regional variances do NOT make climate.
  3. Renewable Baseload Energy
    356 michael sweet You can discount whatever you wish. That's your problem not mine. It is a fact that "nuclear does not do load following" myth crops up frequently. What I said was technically correct and setting the record straight. I also pointed out that grid specific modeling would be needed to determine at what proportion of total capacity nuclear would become uneconomic. It is clearly not minimum system demand. What is your problem with this? How come wind is less 'wasteful' than nuclear (whatever 'wasteful' means)? If wind has excess capacity that cannot be utilized because there is insufficient demand when the wind happens to be blowing, then without subsidy it is in exactly the same position as nuclear run at a low capacity factor - high capital investment being under utilized. Except that nuclear has the outstanding advantage of being dispatchable and reliable and able to perform the very important role of stabilizing the grid. As I said the 'wasteful' argument makes no sense to me and seems to be based on assumptions about how demand can be manipulated to match unreliable supply. You could make exactly the same arguments for reliable supply where demand is managed to a limited extent by off peak rates. I make no apology for the word 'bamboozled'. If I think an argument is nonsense, I will say so.
  4. A Cloudy Outlook for Low Climate Sensitivity
    It's interesting how these posts help illuminate the broader context. On this thread (and others), water vapor is the dominant GHG and its warming effect is far more significant than any possible effects of CO2. Here, water vapor (a prime component of clouds) will keep us cool and comfortable as that irrelevant CO2 continues to build for years to come. Note to skeptics: Read some of your own stuff in context. Then make an attempt to be internally consistent every once in a while!
  5. A Cloudy Outlook for Low Climate Sensitivity
    Re: Camburn (13) The obligatory "we-don't-know-anything-for-sure" drive-by. Despite your baseless assertion, evidence does exist. Unless you have something that shows what we've figured out thus far fails to meet some definition of evidence that you are operating under? The Yooper
  6. The human fingerprint in the seasons
    #75: "Heat as opposed to a redistrubution of temperature are very different things." Presumably you exclude heat that would otherwise be radiated to space from your 'redistribution' concept. But the 300-comments-and-still-growing 2nd Law thread has hashed that out.
  7. A Cloudy Outlook for Low Climate Sensitivity
    Interestingly, this paper: Deep ocean heat uptake as a major source of spread in transient climate change simulations (found from here) indicates that model climate sensitivity is correlated with the model's depth of mixing in the polar oceans. Taking the two together it seems like modelled tropical cloud cover is correlated with modelled polar ocean mixing depth. Does anybody else find this a bit surprising?
  8. Stratospheric Cooling and Tropospheric Warming
    Hi All, I've finished a rough cut of my writeup and offer it to you for comment. I apologize for the roughness of it but you will not have any trouble understanding what I'm saying. Stratospheric Cooling and Tropospheric Warming - Revised Again, nobody has emailed me to tell me who they are and if they would like to be aknowledged. I do feel that I should give credit where credit is due. Bob
  9. A Cloudy Outlook for Low Climate Sensitivity
    There is really no evidence one way or another as of yet as to cloud feedback. There are suggestions going in both directions.
  10. Positive feedback means runaway warming
    #28: "Archer's estimate of the total amount of methane hydrates is on the low end of current estimates." As I said above, its the rate of release that's critical. Since clathrates are so well-distributed around the world's oceans, their volume is quite significant. But a methane release from an Arctic source may occur independently of one in the Gulf of Mexico. "information about it from sources with no known connection to ExxonMobil." Fair point. I note that Maier-Reimer was with the Max Planck Institute when those papers were written. Kheshgi also co-authored a paper with Bert Bolin, who I believe was Chair of the IPCC.
  11. macwithoutfries at 01:13 AM on 6 December 2010
    A Cloudy Outlook for Low Climate Sensitivity
    The other thing to remember is that some of the theories and 'preliminary models' from Spencer and Lindzen are 'almost working' on the descendant part of the solar cycle, however will seriously break correlation during the next 5 years on the ascendant part of the TSI curve.
  12. Renewable Baseload Energy
    Camburn, Think it through. Charging electric cars is fungible. People will charge when the electricity is cheapest. The reason people do not charge up during the day is that it is more expensive (nuclear plants run cheaply at 100% all night:). If solar power was cheaper during the day people would just plug in at work. Then you car could go twice as far with the same battery! Load shifting can substantially change the baseload and reduce the need to store energy.
  13. The human fingerprint in the seasons
    Daniel Bailey #25 "if you feel you have something to add that shows waste heat amounts to more than 1% of GHG forcings, go back to that thread and comment on it there. " This comment (feel free to correct me if I am mistaken) implies that GHG's increases net heat (i.e. raising the energy level). Heat as opposed to a redistrubution of temperature are very different things. Even Arrhenius did not intend this. At the bottom of page 268 (the paper cited), it says, "The geographical annual and diurnal ranges of temperature would be partly smoothed away, if the quantity of carbonic acid was augmented." In the paper, the author is very specific about how the GHG affect latitudes differently, and especially poles and glaciers. Using these arguments to explain global warming is a distortion. The entire point of Arrheniu's paper is to explain a theory of how Nature modulates the coming and going of ice ages (not global warming), and in fact alludes to northern civilizations emerging as a consequence of naturally receding ice and not the other way around.
  14. Renewable Baseload Energy
    Quokka, The pro nuclear reference that scaddenp cites in 355 says that while nuclear can adjust its output, nuclear is not economically competitive unless they run the plant at high power output. This is because of the very high capital costs that nuclear has. To recover the capital cost they run at 100% as much as possible. Since they are pro nuclear, I presume they are accurate. I find your strongly worded statements "Your assertion that nuclear power plants do not and cannot load follow is prevalent myth that is not true" and "I must confess to be utterly bamboozled by this argument" to be a very strong turn off for the nuclear argument. If nuclear is so good, why do the pronuclear people here have to exagerate their position so much? When I see some statements that I know are exagerations I discount the rest of your argument. We need to consider all our options to get out of the mess we are in. It is necessary to consider the pros and cons of all possibilities to find the best solution. I noticed in scaddenp's pronuclear reference that wind was the lowest cost source of electricity in the USA. The USA has much beter wind resources than Australia, there is a lot of wind in the Great Plains. Previous posts on this blog refer to wind farms in Australia that are only 400 km or less apart having similar wind patterns. In the USA, Texas and North Dakota are over 1200 km apart and have mostly separate wind patterns.
  15. Ocean acidification isn't serious
    That seems to say that CO2 is required for photosynthesis. Yes, same for "sea plants" as it is for land based ones. The carbon in the CO2 molecule provides the basis for carbohydrates which are synthesized using energy from the sun.
  16. A Cloudy Outlook for Low Climate Sensitivity
    "David, as I understand it, people in denial (of any sort) grasp for anything that will allow them to keep their illusion that "everything's going to be all right". " Compare this to your own view which is that an unknown but dominant effect in the climate cant and wont help despite whatever becomes known about it in the future. This result is born from yet another model. Its made to sound definititive which is little more than a LOL.
  17. Ocean acidification isn't serious
    Most references I see on coral bleaching list increased temperature as the main stress likely to cause it. Reading the wiki on Coral bleaching seems to offer a contradiction Not really. Coral reef bleaching can be induced by a number of conditions- as listed in the Wiki page. The bleaching events I have previously linked to are truly massive in scale and correspond with anomalously warm, and sustained, sea surface temperatures. Hence the ability to predict these large bleaching events in advance. If you pore over the peer-reviewed literature you will see a lot of debate about the cause in earlier years, however as global warming, and warming ocean temperatures have continued, the evidence identifying warming SST's has strengthened. Try reading the first link I provided at @ 19. The lead author, Eakin, has published a lot of work on corals, and the study gives a good overview.
  18. actually thoughtful at 20:45 PM on 5 December 2010
    The human fingerprint in the seasons
    Phil @ 68, I think I completely understand HR's point - which is why I can show the fallacy of the argument. Read my comment again - I point out that you DON'T need TSI to understand the current post, but it does, INDEPENDENTLY verify that TSI hasn't increased. As to your closing paragraph (perhaps I don't understand your point 100%) - the visual picture that paints is each excited water vapor molecule (heat) interviewing the molecule that bumped into it: "Excuse me - are you excited from TSI?" "Why yes, how did you know?!" [excited molecule jumps up and down, exhibits clear additional excitement] OR "Excuse me - are you excited by a glancing blow from CO2?" "Why yes, how did you know?!" [excited molecule visibly slumps, clearly showing less exitement] Then, of course, your last sentence seems to say the opposite. Can you clarify what you are trying to say?
  19. Ocean acidification isn't serious
    f Found some more current research on wind born problems for coral reefs, from a Government source http://www.usgs.gov/newsroom/article.asp?ID=1970&from=news_side "African Dust Poses Threat to Coral Reefs and Human Health:  Contaminants carried with African dust to the Caribbean and the Americas may be a threat to marine organisms and humans, according to preliminary results of a new study by researchers with the U.S. Geological Survey, Oregon State University, and the University of the West Indies. The scientists compared contaminant levels in sources of African dust and downwind regions. Of the more than 100 persistent organic pollutants screened for in the samples, including banned and common-use pesticides, six pesticides (chlorpyrifos, dacthal, endosulfans, hexachlorobenzene, chlordane, and trifluralin) were detected in samples from all sites. Concentrations were significantly higher in Mali. DDE (a breakdown product of DDT) was also identified in Mali, U.S. Virgin Islands, and Trinidad samples. To date, DDT and carcinogenic dioxins and furans have been detected only in samples from Mali. Many of the identified contaminants are thought to be toxic to corals and other marine organisms and can interfere with reproduction, fertilization, or immune function. For more information, contact Virginia Garrison at 727-803-8747, ext. 3061 or ginger_garrison@usgs.gov." "The Origin of Aspergillus Sydowii, a Common Disease of Caribbean Corals:  Coral reefs are increasingly suffering outbreaks of disease, causing dramatic declines in population abundance and diversity. One of the best-characterized coral diseases is aspergillosis, caused by the fungus Aspergillus sydowii. A. sydowii is a globally distributed fungus commonly found in soil, so its presence in marine systems raises questions about its origin. By using microsatellite markers, researchers analyzed the population structure of A. sydowii from diseased sea fans, diseased humans and environmental sources worldwide. The results indicate that A. sydowii forms a single global population, with low to moderate genetic differences between the disease found in sea fans and the same fungus from environmental sources. Past researchers have suggested that A. sydowii originates from African dust blown into the Caribbean, and have identified Aspergillus from dust samples, although often only to the genus level. To test this, researchers isolated fungi from dust samples collected in Mali and St. Croix. Although a diversity of fungi was documented from African dust, including seven species of Aspergillus, none of the samples contained A. sydowii. Taken in conjunction with recent molecular evidence suggesting lack of a single point source of the fungus, this research suggests  that there are likely multiple sources and introductions of this pathogen into marine systems. For more information contact Krystal Rypien at 858-534-3196, krypien@ucsd.edu or  Virginia Garrison at 727-803-8747, ext. 3061 or ginger_garrison@usgs.gov." "The Emperor Has No Coral? Results of research on coral reefs in the Florida Keys reef challenge the highly popular notion that present declines in reefs in Florida and elsewhere are related to human activities. High-resolution sub-bottom profiling, reef drilling, and mapping of benthic habitats along the reef tract present a paradox in coral growth patterns: reefs that are dead or dying -- and therefore not building -- outnumber live and building reefs about 100 to 1. Yet growth rates of all common coral reef species should have kept pace with the well-documented rise in sea level over the past 6,000 years. Why did so few reefs keep pace or build up with the rise in the present sea level? Geological history may provide an answer: two 500-year periods of non-growth of coral reefs occurred in the region 4.5 thousand years ago and 3,000 years ago. These periods of non-growth indicate times of environmental crises that predated modern human presence in the Florida Keys. The present period of rapid coral demise has spanned only about 30 years. For more information, contact Eugene Shinn at 727-533-1158, eshinn@marine.usf.edu or Barbara Lidz at 727-803-8747, ext. 3031, blidz@usgs.gov." Chris Shaker
  20. A Cloudy Outlook for Low Climate Sensitivity
    I didn't think it could be that simple, thought I was missing something. These guys really believe that cloud cover will carry us through until fossil fuels run out? And then carry us through a lot longer until CO2 levels fall (how?). You have got to be joking, is the obvious comment, but sadly I know they are not.
  21. Ocean acidification isn't serious
    Most references I see on coral bleaching list increased temperature as the main stress likely to cause it. Reading the wiki on Coral bleaching seems to offer a contradiction http://en.wikipedia.org/wiki/Coral_bleaching It says, "Bleaching occurs when the conditions necessary to sustain the coral's zooxanthellae cannot be maintained.[4] Any environmental trigger that affects the coral's ability to supply the zooxanthellae with nutrients for photosynthesis (carbon dioxide, ammonium) will lead to the zooxanthellae's expulsion.". That seems to say that CO2 is required for photosynthesis. Yet, they also state, "Coral bleaching is a vivid sign of corals responding to stress, which can be induced by any of: increased (most commonly), or reduced water temperatures[5][6] increased solar irradiance (photosynthetically active radiation and ultraviolet band light)[7] changes in water chemistry (in particular acidification)[8][9] starvation caused by a decline in zooplankton[10] increased sedimentation (due to silt runoff) pathogen infections changes in salinity wind[6] low tide air exposure[6] cyanide fishing" How much stock am I supposed to put in the 'acidification' mention when CO2 appears to be essential for coral photosynthesis? Chris Shaker
  22. Ocean acidification isn't serious
    Rob: I searched for, found, and read that paper after watching an educational TV program that covered the fungus, possibly a Nova? Chris Shaker
  23. Ocean acidification isn't serious
    Chris , I find it insightful to actually read the studies linked to. The authors are proposing a hypothesis (back in 2000). They claim that two bleaching events in the Caribbean (1983/1987) coincide with increases in dust transport into the region. They lay the foundations for their hypothesis, that's the extent of it. In those two years (1983/1987) anomalously warm waters occurred too. Furthermore 1988 was a year of Caribbean coral bleaching and according the graph in Shinn 2000, this was a year of very low dust import into the region. In the meantime, coral reefs the world over have begun to bleach, as sea surface temperatures rise (see links at @ 19 for instance). I would certainly be interested to see how the authors of that study explain that away on African dust. I don't doubt that the transport of dust into the caribbean region has an influence of the marine life, however the evidence for warming waters as the cause of coral bleaching has strengthened to such a level that scientists are now able to accurately forecast bleaching events: Coral bleaching forecast - Coral Bleaching Likely in Caribbean This Year - Sept 22 2010 And reality: Caribbean Coral Die-Off Could Be Worst Ever - 14 Oct 2010 And yes, coral diseases are a major problem, often after bleaching events have occurred.
  24. Renewable Baseload Energy
    Peter Lang - you were promoting nuclear on economics ground alone. I looked to see what expected nuclear pricing would be. Extremely confusing. I found this reference World nuclear which at least made sense with number that I know well. I gather you think the newer technologies like IFR and LFTR would be cheaper still?
  25. A Cloudy Outlook for Low Climate Sensitivity
    Thanks all. David, I suspect the logic goes that in the short-term, cloud feedbacks will prevent dangerously rapid warming, and in the long-term we'll eventually move away from our reliance on fossil fuels. After all, they're limited resources anyway (particularly oil). I suspect the (wishful) thinking is that we'll run out of oil before climate change becomes too dangerous. And of course there's always the 'warmer is better' mentality - I'm not sure if the Lindzens and Spencers subscribe to that, but many skeptics do.
  26. A Cloudy Outlook for Low Climate Sensitivity
    David, as I understand it, people in denial (of any sort) grasp for anything that will allow them to keep their illusion that "everything's going to be all right". To maintain the fiction is all that matters, even if it means saying the sky is green and the sun rises in the west...
  27. A Cloudy Outlook for Low Climate Sensitivity
    What I have never understood about the Lindzen-Spencer position is what do they see happening in the longer term? The clouds don't stop the CO2 build up, so even if they were right, the rise and rise in greenhouse gas concentrations would overwhelm the cloud effect. Or do they imagine cloud cover getting thicker and thicker for the rest of the century keeping pace with rising CO2? And what would be the effect of that on agriculture and the environment? The only relevant negative feedback would be one that began removing CO2 faster than we could pump it into the atmosphere, and there is, sadly, nothing that can do that. And yet people keep quoting Spencer as if this clouds are some kind of serendipitous mechanism that will providentially save us all, no need to worry, keep burning fossil fuel as fast as you like. Or am I missing something in the logic of all this?
  28. The human fingerprint in the seasons
    Muon, Yes, my graph is essentially a running mean with a 66-year window. (I think this is less than clear on the graph because the curve is justified on the left edge of the aggregation window rather than centered.) The data are noisy and if you can't explain the noise, the best thing to do is average it out. I like to use multiples of 11 because I surmise that the solar cycle will have some effect, and it is about 11 years long on average, and using a window over one complete wave, or multiples of the wave, is the best way to smooth out the noise induced by that wave. As a matter of preference, when I am making a picture depicting the larger effects, I like to average, or otherwise smooth out, the smaller ones. Tom, I read your posts and I hunted up some other material, and I agree it is true that the stratosphere will be cooler than it was even after a new equilibrium is reached largely because of the blockage from below and increased radiative energy loss from above, but I don't believe it is the only game in town. I do have some quibbles: I don't think it is very accurate to categorize the whole troposphere as optically thick. The mean altitude of emission is 5-6km, and that is about half the average altitude of the tropopause. So, the troposphere is getting optically thin at some point below the stratosphere. Optically, I don't think there is a clear cut-off between thick and thin; so, this is somewhat a matter of how they are defined. In a state of equilibrium, a body emits the same amount of energy as it receives. If slightly more insulation is added to the body, then the emission will be less than it was until a new, higher equilibrium temperature is reached. You can't raise the energy level within a body while keeping the inflow the same unless you reduce the outflow. In the case of the earth, the reduction of outflow would be observed as stratospheric cooling. The pattern of a warmer surface and a cooler stratosphere this effect causes would be be hard to distinguish between H2O and CO2. I think you are taking the blanket analogy a bit too literally. If it makes you like it any better, you can say that it is a body in space (like the earth is a body in space) that is tightly covered in a thin insulating layer that does not appreciably change its surface area. I mean, if you define the surface area by using the optical TOA, what is the difference in surface area between an earth with 287 ppm CO2 and one with 385 ppm CO2, and what is this difference in comparison to the total surface area? Without doing the math, I can ballpark it as pretty dang negligible. So, it doesn't make a great deal of sense to introduce the idea that adding more insulation to the body appreciably changes the surface area from which it emits. Convection doesn't transfer energy in space. A cold-blooded animal is a poorer analogy than some generic body of matter receiving energy because said animals in time achieve the same temperature as their surroundings. In contrast, of course, the earth is continually receiving energy from the sun and stays considerably warmer than the surrounding space, if you could say that space has a temperature. Blankets also limit radiative energy loss.
  29. Philippe Chantreau at 17:57 PM on 5 December 2010
    A basic overview of Antarctic ice
    Bill, you make it easy to misinterpret. What exactly are you trying to say, in a few words? This: "My similar statement was not based on the visual graph but was a rough rule of thumb mathematical estimate of the effect of reducing the ice loss percentage by 30 to 40% from subtracting the antarctic ice gain from the arctic ice loss and by increasing the extent by 50% by adding the Antarctic maximum extent to the Arctic maximum extent." What is the point of such manipulations? The only way to assess the significance of global sea ice loss is to examine real global sea ice data. Do it daily, monthly, whatever but I doubt that building fictitious quantities by adding numbers at various times of the year can show much about reality. "Since albedo is an ongoing year round phenomena." In the same sentence, you mention Arctic sea ice, so I assume that the albedo statement pertains to Arctic sea ice. Are you serious? I have very little time to devote to climate blogging these days. From a cursory read of your posts above, it does not appear that your assertion that the global sea ice decline is not statistically significant was supported by a real data analysis. Was it the case or not? What I read from you does not appear any better, a priori, than eyeballing a graph. I contend that data analysis from either NSIDC or CT will show that the decline in global sea ice is statistically significant. I have not the leisure of going at length about it. Tamino looked at the numbers again not long ago: "For the Southern Hemisphere, summer minimum has increased at about 9,000 km^2/yr while the winter maximum has increased at about 14,000 km^2/yr. For the Northern Hemisphere, on the other hand, the decrease in winter maximum has been about 42,000 km^2/yr and the decrease in summer minimum has proceeded at about 81,000 km^2/yr." The differences between these rates leaves little doubt IMO but feel free to attempt proving otherwise.
  30. Renewable Baseload Energy
    The one great advantage of renewables from my perspective is that they circumvent one of the major unknowns of the next century or so. Just how much hotter and drier it will get, and how long will they stay that way, before things improve. Renewables need no cooling water for operation. If France and the USA have already had to take plants offline when rivers ran hot or low, we really don't want to put too many of our eggs in a basket that needs reliable flows of cooling water. And I'd be very reluctant to put a coal or nuclear plant that has to operate 80 years from now at the shoreline to use seawater.
  31. A Cloudy Outlook for Low Climate Sensitivity
    Well done Dana. Of course it's not good news, but it at least gives some support for the "instinct" that low cloud sensitivity was more wishful thinking than anything else. On the bright side, someone else just possibly might do further quality work in this area with a better outlook. (If only.)
  32. Renewable Baseload Energy
    351 Rob Honeycutt
    you are also ignoring that nuclear can't switched off when people go to bed at night. That means you run spin reserve. So, ultimately nuclear is not very flexible. The larger a percentage of output that is dedicated to nuclear the less efficient it is. Renewables are exactly the opposite.
    Your assertion that nuclear power plants do not and cannot load follow is prevalent myth that is not true. French NPPs do adjust output according to load. I understand that German NPPs can also, but there is probably no grid requirement to do so. Areva states that the EPR can adjust output from 60% to 100% of nameplate capacity at the rate of 5% of nominal capacity per minute at constant temperature. (as per Areva website). Nuclear can handle base and a large portion of intermediate load economically. Exactly at what point it may be uneconomic would be grid specific and could only be determined by detailed modeling. I must confess to be utterly bamboozled by this argument that renewables are less "wasteful" - without even defining what wasteful means. One of the characteristics of grand plans for renewables is the requirement to overbuild capacity precisely because of the intermittent and unreliable nature of the generators. I would be very cautious of claims that demand can be time shifted by smart grids and clever gadgets until we see in practice the magnitude of any such change. I'm not prepared to bet the future of the climate on this stuff.
  33. It's albedo
    And, back to the previous question: "Has it been proven that the equilibrium temperature of a body in a constant EM radiation field can be altered by altering it's reflectivity [...] Is it not necessary to demonstrate that in order to prove that albedo or aerosol-based reflectance can influence the global mean temperature?" There are actually quite a few different ways you can see this operating in the real world. If you live in a place where it snows in the winter, you might notice dirty snow melting faster than clean snow -- because its lower albedo causes it to absorb more sunlight and warm up faster. The same principle is what makes ice ages cold ... as the large continental ice sheets expand, they reflect more sunlight back to space, which makes the local climate cooler, which helps the ice expand further. (When they begin melting, at the end of each glacial episode, the same process happens in reverse -- the loss of ice makes the landscape absorb more sunlight, making it warmer, which melts the ice further....)
  34. It's albedo
    Rovinpiper (bagpipes?), try playing with this calculator.
  35. It's albedo
    Hi, Rovinpiper. Good questions you're asking. Kirchoff's Law refers to absorptance and emissivity at the same wavelength -- i.e., an object's emissivity at a given wavelength will equal its absorptance at the same wavelength. In the case of a planet (e.g., earth), almost all the radiation it receives from the sun is at short wavelengths (UV, visible, and near-infrared). In contrast, all the radiation it emits is at long wavelengths (> 3 micrometers). So, a change in the earth's albedo can increase or decrease the amount of energy that is absorbed, without necessarily increasing or decreasing the amount of energy that is emitted. When this happens, the planet then warms or cools until the outgoing radiation is once again in balance with the incoming radiation. Hopefully that's clear. It's around midnight here and I'm not really a night person, so my explanations may not be all that coherent......
  36. It's albedo
    Hi Tom, Thanks for replying to my question. Do you have a solid source for a proof of that? I just read about Kirchoff's Law and it seems to say that if the Earth becomes more reflective it becomes less emissive by an equal amount and so temperature remains unchanged.
  37. A Cloudy Outlook for Low Climate Sensitivity
    Excellent post Dana. It is so sad that the data look so bad.
  38. Positive feedback means runaway warming
    Hi muoncounter- I've read one of Archer's papers, but it's been a few months and I'll reread it. I'd feel more confident in Archer's stuff if he hadn't written several joint papers with ExxonMobil chief scientist Kheshgi: ExxonMobil Contributed Papers on Climate Science
    17. Archer, D., Kheshgi, H., and Maier-Reimer, E. 1997. Multiple Timescales for the Neutralization of Fossil Fuel CO2, Geophysical Research Letters, 24: 405. 19. Archer, D., Kheshgi, H., and Maier-Reimer, E., 1998. The dynamics of fossil fuel CO2 neutralization by marine CaCO3, Global Biogeochemical Cycles, 12:259-276. 35. Kheshgi, H. S. and Archer, D. 2004. A non-linear convolution model for the evasion of CO2 injected into the deep ocean. Journal of Geophysical Research,109, C02007, doi:10.1029/2002JC001489. 13. Kheshgi, H. S., and D. Archer, 1999: Modeling the Evasion of CO2 Injected into the Deep Ocean, in Greenhouse Gas Control Technologies, edited by B. Eliasson, P. Riemer and A. Wokaun, pp. 287-292, Pergamon.
    I can see why an earth scientist might collaborate with ExxonMobil, or it's chief scientist. They undoubtedly have a monumental knowledge of geology, and an immense treasure trove of geological information. Having said that, though, Archer's estimate of the total amount of methane hydrates is on the low end of current estimates. It's a really important subject, and I'll get my information about it from sources with no known connection to ExxonMobil.
  39. Roger T. Thomes at 14:05 PM on 5 December 2010
    A Cloudy Outlook for Low Climate Sensitivity
    This is a superb article. Here is something that is not dumbed-down. There are enough facts on this topic to allow the readers to make their own conclusions.--R.T. Thomes
  40. A Cloudy Outlook for Low Climate Sensitivity
    My name's not John, but thanks dansat! Bob Guercio - I agree, the odds are not too good that Lindzen and Spencer are right. Not nearly good enough to bet the farm on.
  41. Stratospheric Cooling and Tropospheric Warming
    Daniel, This is the other cause of cooling of the stratosphere. However, this is relatively easy to understand and I do not want bring it into my writeup because it will only confuse the very complex mechanisms that cause greenhouse gases to cool the stratosphere. But yes. Thinning of the ozone layer also causes the stratosphere to cool. Bob
  42. A Cloudy Outlook for Low Climate Sensitivity
    Richard Lindzen and Roy Spencer believe that the formation of low level clouds resulting from global warming will result in a negative feedback keeping the warming in check. I just don't get it! How much statistical certainty do they have that this is going to happen? My guess is "not too much" so where is the logic in taking such a chance with our only world. Furthermore, suppose they can give a certainty which is ridiculously high, say 99.99% Does it really make sense to allow the chemistry of the planet to change so drastically considering the unknown and potentially devastating consequences? Like I said "I just don't get it!" Bob
  43. A Cloudy Outlook for Low Climate Sensitivity
    That's a heavy weight paper. Had not seen it yet. You deserve your growing reputation John! Thnx for the post! Dan
    Response: This post was written by Dana (who does deserve his heavyweight reputation as he's written most of the advanced rebuttals).
  44. Stratospheric Cooling and Tropospheric Warming
    From one following the discussion as best I can, thought I'd throw this out there:
    "The loss of ozone that has occurred in the Antarctic lower stratosphere during each spring since 1980 has led to a decrease in the lower stratospheric temperature that persists into the summer season." "Comparison of the summer temperatures in the NH and SH indicates a distinctive offset beginning around 1980. The increase in temperature near the SH summer mesopause has implications for the presence of polar mesospheric clouds." "The Antarctic ozone hole is perhaps the largest persistent perturbations to the atmosphere during recent decades. As shown here, the climate impacts of this anthropogenic change extend into the upper mesosphere. As the ozone recovers in upcoming decades, we expect to see shifts in the SH summer mesopause that bring it closer to that in the NH."
    From a science news article in Science daily; free copy of source study available here. A good chunk of the study goes over my head, like much of this thread. But these caught my eye (eye-candy, heh-heh): and If this was discussed already here, my apologies. The Yooper
  45. 2009-2010 winter saw record cold spells
    Muoncounter - I'm talking about the cold winter UK, in particular, being a regular occurrence, based on changes in the Arctic Oscillation. Not the "but there's record cold in Wagga Wagga" or whatever line the skeptics cling to. Sure it's likely to be a transient phase (the rest of the world will still be getting warmer) but I expect a similar future break-down in the circum-polar winds around Antarctica (Southern Annular Mode) will lead to similar outbreaks of cold weather. Living in New Zealand, that may affect me personally, but I probably won't be around when that happens.
  46. 2nd law of thermodynamics contradicts greenhouse theory
    #299: "nonsensical claim that planetary albedo is irrelevant to temperature" We went through a week or so of back-and-forth on the Chaos theory and global warming thread over 'climate calculators' that show specifically how albedo influences temperature. Seemed like a no-brainer at the time.
  47. The human fingerprint in the seasons
    #69: "It isn't exactly what I was expecting." When you do mean:66 after doing every:12, aren't you averaging 66 years? Cutting back even to a 30 year mean gives a cleaner break between NH summer and winter; SH summer and winter are overlain.
  48. Stratospheric Cooling and Tropospheric Warming
    Bob @133, this is correct, and I must have misunderstood what you where asking. My claim was only about the stratosphere which will (I believe) reach a steady state very quickly given constant inputs. Whether "very quickly" is a few month or a couple of years I'm not sure. @144, I believe this is correct, with motion of the whole molecule contributing to temperature, while vibration contributes to heat capacity. I am, however, not sure. In passing, Joe Blogg's first paragraph @146 is a brilliantly succinct explanation of optical depth as related to this issue. Regarding your furture article, in a topic this subtle, I suspect it would be better to write an advanced version first, and only post a basic version once the advanced version is up. When you write a basic article, you may be able to do something along the lines of comment by Nullius in Verba at Science of Doom. Doing this, I would not treat the temperature profile as a rigid bar, but rather treat the stratosphere seperately from the troposphere. Essentially, you would be appealing to the not often commented upon fact that in the presence of a negative lapse rate, greenhouse gasses cool rather than warm.
  49. The human fingerprint in the seasons
    @69, I don't particularly like that analogy because blankets work by limiting convection. As such they can have very low emissivity and their final radiant energy can still be much less than the initial radiant energy of the body covered. However, going with the analogy, it is more accurate to consider a blanket partially covering a cold blooded animal. Once a steady state is reached, there will be less energy released per unit surface from the blanket than there is from the exposed body, or there was from the exposed body before being covered.
  50. The human fingerprint in the seasons
    Chris G #67, you may be failing to consider that the troposphere is optically thick in the 15 micron (CO2) band, while the stratosphere is optically thin. Because the troposphere is optically thick, if you increase CO2 the net outgoing radiation will stay relatively constant but originate slightly higher in the atmosphere. (The increased altitude will mean the source CO2 will be slightly cooler, resulting in a slight reduction in outgoing CO2.) In contrast, because the stratosphere is optically thin, absorption will approximate to the Beer-Lambert law, so doubling CO2 will approximately double absorption and emission. The effect of this depends on the difference between tropospheric and stratospheric temperatures. If the stratosphere were cooler than the upper troposphere by an amount greater than the change in temperature at the effective altitude of radiation for the troposphere, then the effect would be to warm the stratosphere. Otherwise the effect is to cool it. More importantly, doubling CO2 concentration will double the amount of energy absorbed by CO2 in collisions; and double the amount of that collisional energy radiated away by CO2. A significant source of that energy is UV radiation absorbed by ozone. Because, with higher concentration, the CO2 would be radiating away that energy more efficiently, the stratospheric temperature will drop to reestablish a steady state. I believe this to be a larger effect than the first one. I have discussed this in more detail on the Stratospheric Cooling post on this site, particularly at comment 83 and comment 120.

Prev  2036  2037  2038  2039  2040  2041  2042  2043  2044  2045  2046  2047  2048  2049  2050  2051  Next


The Consensus Project Website

THE ESCALATOR

(free to republish)


© Copyright 2024 John Cook
Home | Translations | About Us | Privacy | Contact Us