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  1993  1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  Next

Comments 100001 to 100050:

  1. Did Global Warming stop in 1998, 1995, 2002, 2007, 2010?
    HR: "Do crops get damaged by weather or climate?" Erm, I live in the UK and often listen to a BBC radio programme called 'farming today'. Firstly lets start with the weather on the South Coast from Sept through to Dec 2010. Basically from Sept to Nov, it was incredibly warm for the time of year. Secondly the warm weather generally has resulted in bumper crops in some cases, the main problem is harvesting vegetables (eg. brussel sprouts). According to a organic farmer on 'farming today', he can harvest most of his crop at temperatures down to -10. Below that, the crop rots when it thaws. Actually what we do have in the UK is crop migration due to warming, which is why Camel Valley vineyard in Cornwall no longer has to use poly-tunnels to protect their vines. You also seem to have forgotten that Wheat prices have shot through the roof due to Russian droughts and wild fires. As has been stated in previous comments, a graph of crop yields has little to do with eventual production figures, carry over etc. The subject of climate change impact on farming and species is complicated. Simple statistics do not show crop migration (farmers adapting to changing climate) and other issues. UK organisations such as the Tree Council and the Forestry Commission are looking at trees that will grow in changing climates in the UK, including Oaks that have adapted to warmer climates in France.
    Moderator Response: Additional discussion of crops must move to a more relevant thread such as "It's Not Bad."
  2. A Positive Outlook For Clouds
    Nick - water vapor is a significantly less powerful greenhouse gas than CO2. It's just more prevalent in the Earth's atmosphere, thus it accounts for more of the greenhouse effect. Atmospheric water vapor will indeed increase as the planet warms - there's really no question about that. 'Skeptics' like Lindzen simply postulate that the negative cloud feedback will be so strong as to overwhelm both the CO2 forcing and all positive feedbacks, including water vapor. I can't speak for how sure Lindzen is, but I think the evidence clearly shows that we would be unwise to put our eggs in the 'cloud feedbacks will save us' basket.
  3. A Positive Outlook For Clouds
    If we speculate that there will be more clouds around as a feedback to CO2 induced warming, there will also be more water vapour around (needed to form them). Leaving aside the reflectivity due to the clouds, there will be plenty more water vapour (uncondensed) in the areas between and under the clouds. I am probably showing the limits of my knowledge here, but, as water vapour is a more powerful greenhouse gas than CO2, have Lindzen et al taken into account that whilst his hypothesized "Iris" like effect is reducing the radiative forcing, the increased water vapour necessary to generate the extra "Iris" clouds will be increasing the forcing right back up again? How sure is Prof. Lindzen which effect will dominate? Anyone?
  4. Did Global Warming stop in 1998, 1995, 2002, 2007, 2010?
    Albatross: Now either you support that trickery or you do not. So, where do you stand on that? I think HR's use of a cherrypicked FAO graph answers that question for him. Meanwhile, FAO's 2009 Profile for Climate Change notes that "Climate change negatively affects the basic elements of food production, such as soil, water and biodiversity." Furthermore, "it affects all four dimensions of food security: food availability, food accessibility, the stability of the food supply and the ability of consumers to utilize food including food safety and nutritional value." Therefore, "Action is needed now, [because] inaction will significantly increase future costs." In other words, FAO seems to agree with this article's claim that AGW is "more than enough to disrupt weather systems and cause severe damage to crops and human populations."
  5. The Scientific Guide to Global Warming Skepticism
    Paul Barry, my explanation for (b) is that like most parts of the climate system, ocean heat storage is not a nice monolithic, even process. The graph in the guide is crude. But looking at the ENSO numbers here http://www.cpc.noaa.gov/products/analysis_monitoring/ensostuff/ensoyears.shtml it shows that whenever there is strong El Nino (ocean releasing heat) there is a leveling off or dip in the OHC chart (e.g. early 80's, early 90's, 1998). So basically the ocean is storing heat over the long run but the rate of storage can fluctuate based on weather-related ENSO cycles in the Pacific.
  6. Did Global Warming stop in 1998, 1995, 2002, 2007, 2010?
    HR @27, This thread is about skeptics cherry-picking dates to fallaciously and misleadingly make claims about global temperature trends, and changing their dates for "global cooling". Now either you support that trickery or you do not. So, where do you stand on that? Then you can address your unreferenced graph and claim that crops are holding up "pretty well"-- although that discussion is probably better suited on another thread.
  7. Hyperactive Hydrologist at 03:56 AM on 29 December 2010
    Did Global Warming stop in 1998, 1995, 2002, 2007, 2010?
    This is why temperature changes need to be considered on the decadal timescale. HM, poor choice of graph. That is just showing yield of crops per unit area which is pretty much meaningless in the context of your argument. Of course crop yields are going to increase as agriculture becomes more intensive. I bet those figures also correlate quite nicely with fertiliser production.
  8. Did Global Warming stop in 1998, 1995, 2002, 2007, 2010?
    "While these increases do not sound like much they are more than enough to disrupt weather systems and cause severe damage to crops and human populations." Do crops get damaged by weather or climate? Long term agriculture production seems to holding up pretty well in the face of this onslaught.
  9. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    Batsvensson, Indignation is not a viable substitute for published research. If your way of thinking is based on indignation than you are correct that it isn't compatible with a way of thinking based on independently validated, empirical research.
  10. Did Global Warming stop in 1998, 1995, 2002, 2007, 2010?
    24 dhogaza So you are using two predicted temperature reading from one location to re-inforce the idea that Argus is a terrible cherry-picker? No comment. Just to be clear you're telling the population of the UK the weather is "dead normal" at the moment?
  11. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    @batsvensson: "This is indeed true, nor have the skeptic publish a paper which demonstrate that the ears of the global warming camp has no significant effect on the climate system. But should a precaution principle make us cut them off anyway? I don't think so." This is a ridiculous, and faulty, analogy. The "global warming camp" hasn't claimed its ears have an effect on climate, nor do they have a mountain of evidence to support it. Meanwhile, the growing body of evidence supporting AGW cannot be ignored by skeptics. If they want to disprove it, they need evidence presented in peer-reviewed paper to support their claim. AGW being the accepted science, the burden of proof is on skeptics to disprove it. "It seams to me that the aim of this article is not to present a objective scientific picture but to paint up all skeptical people as being a minority with lunatics ideas." I don't get that, however it is true there are very few skeptics who seem to follow the scientific method while promoting their views. Case in point: the many contrarians on this very web site who keep repeating the same debunked theories, jumping from one topic to the next when cornered and confronted with their own contradictions. "Unfortunately what you believe is far for the truth and even more unreachable is the idea of coming to an understanding in each others way of thinking." Science is not negotiations. There's no "two sides to each story." There's the truth, and our attempts to get to it. We don't have to "come to an understanding" with skeptics, deniers and contrarians: they have to come up with the evidence to support their claims, and be prepared to admit they were wrong when their arguments are defeated.
  12. Lindzen and Choi find low climate sensitivity
    #429: "I understand there are many time constants,... " Merely stating that you understand something doesn't necessarily make it so. We've heard all about time constants before. And yet the basic disregard for the entirety of thermal inertia evidenced here and in other prior postings continues. "the 25 years of data I used was to extract the response ..." Except, as pointed out in a number of prior comments, neither RW1 nor you accept the fact that there has already been greater temperature change (and a greater rate of temperature change) than your so-called sensitivity predicts. So you do not have the full response in your model. Perhaps it's time for a new model. Let's boil it down to essentials: You show that instantaneous magnitudes of seasonal heating/cooling and other short-term variations far outweigh the GHE. Everyone else understands that those changes average to 0 over the course of the year (or cycle) and therefore contribute nothing to the long term warming trend. In fact, nothing you've presented contributes to any long term warming. And yet you insist that you have calculated a 'sensitivity', so you must accept that there is long term warming. Thus we arrive at a contradiction between your model and your stated position. I suggest the two of you do the homework (off line, as we do not need to see it played out here) to resolve this basic internal contradiction.
  13. Stratospheric Cooling and Tropospheric Warming - Revised
    @RSVP: "Whether an IR energy packet gets picked up by a GHG or reaches outer space is indifferent to the surface. It looses this energy the same." Sure, the surface does lose the energy, but the capture IR packet is eventually released, and may go back to the surface, warming it again (and thus making the system retain more energy than if it escaped into space). Stop running in circles, and try learning some actual science.
  14. The Scientific Guide to Global Warming Skepticism
    I was going to print the guide out to give to a skeptical friend, but now I am hesitating because of several confusion black spots (rather than actual errors) which I see it containing. I know he will be alert to these because, although he is not fully abreast of climate change science (who is anyway?), he is clever and knows enough science to spot problems straight off. Sadly there are plenty. I’m going to point to just two now: (a) the figure showing an example of a positive feedback on page 3 and (b) the figure showing build-up of Earth's total heat content on page 4. They immediately raise questions. I wouldn't be concerned so much if it was easy to find answers to these questions by searching the site. Unfortunately that's not the case. (a) The example of positive feedback on page 3 has a caption saying “Warming causes oceans to give up more CO2”. Elsewhere we are told that the oceans are getting more acidic - i.e. more dissolved CO2. So which it? Is CO2 in the ocean going up or down or both? Is it different in different places? Is one from the deep sea and the other not? Why is it so paradoxical, if so? (b) The graph of Build-up in Earth’s total heat content. My problem here is a bit harder to explain. I’m fascinated by that graph of increasing ocean heat energy. I’m also confused by its seeming variability. Why is it going up in such a stagger? Where is the heat going when it seems to level off every decade or so? So I look at the reference at the back and I see it is from Murphy et al in 2009. Hmmm. 2009 that’s good - recent. But wait. Hang on. It says: “Figure redrawn on data from paper supplied by Murphy.” Hmmm. It would be better to get a graph taken from an actual paper. So I check around the site here doing searches for ocean heat content and I can’t find this graph or anything similar. I know it used to be here somewhere. Has it disappeared? All I can find are rebuttals of claims that the ocean cooled during the last decade. Not quite the same thing, though, is it? Why isn’t there more information on this graph? How reliable is it given that ocean temperature data are supposedly so vexatious and that reliable temperature measurements, we are told, are almost non-existent until recently? How is heat content calculated, roughly? Does it include the whole ocean or is it just a part? I really feel that this graph needs more explanation. It is probably the most interesting graph I’ve seen illustrating global warming. If it is reliable, why isn’t it shown more often? You can see how suspicions arise in the mind just following this line of thought. I would really appreciate it if someone could provide satisfactory answers to these questions for me - pointing elsewhere if necessary. I would be even more delighted if my queries give rise to improvements to the clarity of the site and the guide too. Please keep up the good work, it is greatly appreciated.
    Response: "Is CO2 in the ocean going up or down or both?"

    CO2 in the ocean is going up. The ocean is building up CO2 because it's absorbing much of the CO2 we're emitting. But as the ocean warms, it's ability to absorb CO2 is lessening. So we are seeing more of our CO2 emissions remain in the atmosphere each year (the airborne fraction). The trend in the airborne fraction is slight, teetering on statistical significance.

    "I’m fascinated by that graph of increasing ocean heat energy. I’m also confused by its seeming variability. Why is it going up in such a stagger?"

    I haven't discussed this with Dan Murphy, author of the paper where that graph came from, but my speculation is the variability in the ocean heat graph is because he calculates total ocean heat from the upper ocean heat content. Upper ocean heat shows more variability compared to the total ocean heat calculated to greater depths because the upper ocean exchanges heat with the deeper layers. This is why when you see graphs of heat over 0 to 700 metres, the heat content jumps up and down while graphs of heat down to 2000 metres deep show a more monotonic increase in heat.

    To calculate ocean heat back to 1950, Murphy had to use ocean data calculated from measurements of the upper ocean. To extrapolate this to deeper waters, he used studies that found the heat accumulating in the deep ocean was around 30% of the heat accumulating in the upper ocean. Thus if he'd have had access to direct ocean heat measurements down to the abyssal depths, I'm guessing the ocean heat graph would've shown less year to year variability. That's just speculation on my part.
  15. Did Global Warming stop in 1998, 1995, 2002, 2007, 2010?
    #18, #20: See the 'Its freaking cold' thread, where our old friend BP has weighed in on this question.
  16. Comparing all the temperature records
    #49: "I was talking about a bias ... " Apparently a 'bias' that is in the eye of the beholder. I did not say anything questioning the value of your "longest cold spell"; I merely said that I was sure that you understood the importance of using significant measures as valid discussion points. If anything, the most common bias here is against making judgments on the basis of too few data points. We just don't like cherries and those who pick 'em are suspect.
  17. Comparing all the temperature records
    "Thank you for pointing out how insignificant my "longest cold spell" is! I had a hunch about that when I wrote it. But the long heat spell this year around Moscow, was very significant, as we all know." Significant, how? As "proof of global warming"? No, but it falls into a lengthening trend of extreme high temperature events being much more frequent as extreme low events. This is exactly the pattern of extreme events one would expect in a warming world. And, it was a much rarer event than your cold spell, as Russian meteorologists have described it as "unprecedented" - proxy reconstructions going back 1,000 years show nothing at all like the month long heat wave. Also, while Stockholm has been cold, it's been raining in the capital of Greenland, and ice in Hudson's Bay has been melting, resulting in exceptionally low sea ice extent in the Arctic at the moment: http://nsidc.org/data/seaice_index/images/daily_images/N_stddev_timeseries.png
  18. Stratospheric Cooling and Tropospheric Warming - Revised
    RSVP - I will have to qualify my last post; this particular example hasn't been discussed much, and there may be some points I wasn't clear on. However: The greenhouse effect is all about rates, not fixed amounts, and your "double duty" fixed amount postings are a complete strawman - an incorrect distortion of the system under discussion. It's a deeply invalid analogy, and arguing from it is a logical fallacy.
  19. Stratospheric Cooling and Tropospheric Warming - Revised
    RSVP - "it is not clear how the box can emit anything" Through the same clear window through which the 100W bulb light comes in. Energy (visible light) continuously comes in, warms the black plate, continuously radiates out (Stephen-Boltzmann equation) as IR - an ongoing flow. GHG's make the flow out less efficient, energy builds up, the plate temperature rises, until outgoing equals incoming again. Again, rates, not fixed amounts! Honestly, RSVP, if you cannot understand these very basic characteristics of the greenhouse effect, and of the analogy, after so many cycles of explaining it to you, there's really nothing more I can say - you either won't or can't listen.
  20. Comparing all the temperature records
    Argus, you claim that it is commonplace for a warming trend of just ten years to be considered completely acceptable as a valid indication of warming on this website. Please. Cite examples. I can't imagine that being true for anything except an extreme warming signal where the degree of change clearly overwhelms the noise signal even over such a short time frame... and I can't actually think of any examples of such. I have seen a few instances of short warming trends being cited... but they were always followed by caveats and notes about lack of significance. You claim otherwise... so please, prove your case. Post some links.
  21. Did Global Warming stop in 1998, 1995, 2002, 2007, 2010?
    Actually, The Ville, the strawman's even more flimsy than you say ... "An all time record cold spell in Europe, however, is worth nothing." Argus ... this year's not been an all-time record cold spell in Europe ... and temps in London, for instance, are forecast to hit 50F tomorrow and will then drop into the low 40s later this week ... dead normal. Meanwhile, the capital of Greenland is forecast to be 24F above the historical average for January on Sunday ...
  22. Did Global Warming stop in 1998, 1995, 2002, 2007, 2010?
    Re Argus @ 19 Rubbish! You are making accusations about articles where references to specific events are made while leaving out the surrounding context. You are "cherry picking" to make a claim of "cherry picking".
  23. Did Global Warming stop in 1998, 1995, 2002, 2007, 2010?
    Re mspelto@20 Thanks for pointing that out.
  24. Did Global Warming stop in 1998, 1995, 2002, 2007, 2010?
    Argus: "But don't forget that 'warmists' also frequently take selected areas of the world where heat records for the recent past are being set, while ignoring other areas where cold records are being set" That is complete junk. You have created a straw man. eg. you have fabricated an entity in order to knock it down.
  25. Comparing all the temperature records
    48: "Sorry, but you are incorrect." Yes, of course, I am incorrect if we are talking about real science. I was talking about a bias that I have noticed in the writings on this website, a bias that is more forgiving towards faulty statistics in showing evidence of warming, than the opposite. Thank you for pointing out how insignificant my "longest cold spell" is! I had a hunch about that when I wrote it. But the long heat spell this year around Moscow, was very significant, as we all know.
  26. Did Global Warming stop in 1998, 1995, 2002, 2007, 2010?
    The impact of Siberian snowcover on NH winter temperatures and weather patterns is not a new idea, that has been around in climate models since the early 1980's. Employing the snowcover data with forecast success in a long term forecast model is new. It is a follow up on the research published by Gong, Frei and Cohen beginning with Gong et al (2003)and a second aper by Gong et al (2003)
  27. Did Global Warming stop in 1998, 1995, 2002, 2007, 2010?
    "'Skeptics' also take selected areas of the world where cold records for the recent past are being set while ignoring other areas where all time heat records are being set." Yes, that is true. But don't forget that 'warmists' also frequently take selected areas of the world where heat records for the recent past are being set, while ignoring other areas where cold records are being set. For example, I have seen many comments on this web site, where heat records from the current year, 2010, are taken as strong indications of climate change. That is a time period of less than one year! The key point here seems to be "all time". As soon as there is an all time heat record on Ascension Island or in some town in Finland, it qualifies as evidence of a change in climate. An all time record cold spell in Europe, however, is worth nothing.
  28. The Scientific Guide to Global Warming Skepticism
    John- great book! I've got one request, which is to have the next edition available as a single column instead of/as well as two columns. With a lot more people reading on the screen and on e-readers, two columns are a pain as you have to go to the bottom of a page, then scroll back up to the top, then back down again. A single column allows you to make the best use of the available screen space (i.e. half the page isn't taken up with stuff you shouldn't be reading yet).
    Response: That's an interesting question. I'll have to investigate the specs of ebooks and how one would put together an ebook version for readers like Kindle and iBooks, both of which I use on the iPad (so I welcome any technical tips from those wise in the ways of ebooks - please feel free to contact me).
  29. Conspiracy theories
    "There is a huge difference between the two. Corporations are designed to create 'fantasies' for humans, whether that is insurance, bank accounts, cars or light bulbs. Those fantasies can be anything (like Marmite flavoured chocolate I saw today!). Corporations are guided by how much they can manipulate the public and governments." Wrong corporations are designed to make a profit and if they can do that by selling you 'the right to pollute' then they will, as for how much they can control government's that just depends on how much money they are willing to offer presidential candidates, congressmen, members of parliment etc etc. of course the interests of science and business are different as its often hard for people to get funding, now if you had the idea to sell a prolific pollutant but you needed a 'scientific' opinion in order to better sell that idea to big business it wouldnt be naive to imagine SOME people might be willing to agree in exchange for research funding. none of the scientists who disagree or question anthropomorphic climate change have been granted UN funding
  30. Ocean acidification isn't serious
    The link to the IAP-statement no longer works. It needs to be updated to http://www.interacademies.net/10878/13951.aspx
    Moderator Response: Link has been updated.
  31. Did Global Warming stop in 1998, 1995, 2002, 2007, 2010?
    There is an interesting article in The New York Times by Judah Cohen about the current Northern Hemisphere winter: http://www.nytimes.com/2010/12/26/opinion/26cohen.html?_r=2&ref=opinion Cohen works for AER. I didn't know anything about this company until I read the article. Apparently AER have a new model that shows the Siberian snow having a big impact on the winter elsewhere. It successfully predicted last years winter and this years. News release in 2002: http://www.aer.com/news/pr/2002/2002-11-18-cold_winter.html The main point made is that it is most definitely a feature of global warming.
  32. Lindzen and Choi find low climate sensitivity
    Whoops sorry. I realise some confusion. 3.7W/m2 is radiative forcing (no feedback) for GHGs. Without feedbacks that's 1 degree of temperature rise - and this is regardless of type of forcing. However, this article is about sensitivity = the surface temperature rise associated with doubling of CO2. The feedbacks are what change 1 degree change for radiative balance to 3.2 degrees of actual warming. And yes, you have to run the physics to sort out the feedbacks so you can take into account the temporal, spatial, and spectral differences in the types of forcings.
  33. Stratospheric Cooling and Tropospheric Warming - Revised
    KR #89 "The box now receives 100W, but only emits 95W " KR #90 "please do not introduce strawmen." Unless there is some place for the energy to go, it is not clear how the box can emit anything. I have no intention (or need) to introduce strawmen, as in fact the discussion started with the following.... An earlier post of mine #85 "Consider a cylindrical thermos container with a double plated glass on one end...I assume you would agree that in pointing an IR detector at the glass (from outside the cylinder), " All this goes back to the "double duty" comments on this thread. The idea that it normally takes energy to raise something's temperature, coupled with the idea that you cant normally create energy, and that when you consider a surface plus a gas, you are talking about more things, not less things. So any IR energy from the surface responsible for heating a GHG, is lost from the surface. Whether an IR energy packet gets picked up by a GHG or reaches outer space is indifferent to the surface. It looses this energy the same. And in taking a step backwards and considering the entire "system" that includes both fluids and solids, the same energy from the Sun is now simply more dispersed if more of it is retained in the fluid part. Overall, it would appear there is more ways for the energy to escape, not less. However, if this represents slightly higher transient atmospheric temperatures during the day, it also represents slightly lower surface temperatures in kind... and I will grant that the surface cooling is also tempered by the backradiation you are talking about, which will normally be much much less than what is emited by the surface.
  34. Lindzen and Choi find low climate sensitivity
    RW1 - how did you think it was calculated? There are empirical constraints on sensitivity, but the numbers come from running the physics and seeing what the number comes out to be. Actually, the mean is 3.2C, not sure where you get 3.7. Its an output of model, global average of the temperature that accompanies model run with a doubling of CO2. To see "how it pans out", see the various model estimates but read that section of the IPCC report to understand why they vary. Milankovich cycles are always operating, but the point of my explanation was to show that you cannot ignore spatial distribution of forcing in calculating feedback. True for Milankovich, true for CO2. I dont understand your comment about sun being "only source of energy in the system". Any suggesting otherwise? GHG are about impediments to surface radiative efficiency and changes to surface temperature.
  35. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    Just to pick one flawed argument from the OP: "While the skeptics [...] can not produce a set of key papers which demonstrate that doubling atmospheric chemistry has no significant effect on the climate system." This is indeed true, nor have the skeptic publish a paper which demonstrate that the ears of the global warming camp has no significant effect on the climate system. But should a precaution principle make us cut them off anyway? I don't think so. - It seams to me that the aim of this article is not to present a objective scientific picture but to paint up all skeptical people as being a minority with lunatics ideas. If what you wrote you really believe in then I can understand why you think as you do. Unfortunately what you believe is far for the truth and even more unreachable is the idea of coming to an understanding in each others way of thinking.
  36. Lindzen and Choi find low climate sensitivity
    KR, Yes, I understand there are many time constants, but the one that matters, relative to the measured response, is that which quantifies the response of the thermal mass of the planet. Also, the 25 years of data I used was to extract the response, from which the consequence of a change can be predicted and is not constrained by your requirement of 25-30 years to ascertain a trend, even though the data set is long enough. In this case, extending the data set results in the inclusion of the longer term effects as they affect the response. The response to a linear change can also be extracted from the LTI by setting the forcing function to a ramp from which the steady state solution can be solved.
  37. Lindzen and Choi find low climate sensitivity
    scaddenp, "It doesnt, I agree, but as I said, 1W/m2 as global annual average has a very different temporal, spatial and spectral distribution for sun versus CO2. The direct radiative balance is obviously maintained but to consider a simplification, 1W/m2 could by say 2W/m2 in one hemisphere and 0 in the other. The temperature response for radiative balance is 0.6 in one hemisphere, 0 in the other still for global average of 0.3." The radiative forcing of 3.7 W/m^2 from a doubling of CO2 is a global average just like average solar input is. How do you think each is calculated? Are you forgetting that the Sun is pretty much the only source of energy in the system? "Sensitivity it about feedbacks though. The milankovich forcing driving the ice age cycle is tiny as global average, but the large forcing at 65N over long time delivers feedbacks enough to drive the cycle. The identical forcing at 65S does not - far less scope for feedbacks in the south." We're not due for another Milankovitch cycle for long time. Plus, it's mainly the change in the distribution of the energy from the Sun that is apparently enough to overcome what appears to be a very strong net negative feedback operating on the system. "You have to run the physics and see how it pans out." OK, run "the physics" and show us how it pans out.
  38. Lindzen and Choi find low climate sensitivity
    #422: "A*exp(-t/tau)," Nope, that's exponential decay to 0. What you want is y=A(1-e^(-t/tau)), which asymptotes to A. "climate system responds slower than seasonal change. This is clearly wrong because if it was the case, seasonal change would not happen!" Mistaking weather (seasonal, small tau) for climate (multi-year, long tau)? So climate systems do indded respond more slowly than seasonal changes, as KR demonstrates in #423. That's why seasons aren't climate.
  39. Species extinctions happening before our eyes
    nofreewind last posted on October 10th. His "rebuttal" on August 16th did not pass moderation, probably because it was lame and uninspired. Been running silent, running deep since... The Yooper
  40. Lindzen and Choi find low climate sensitivity
    RW1 - your references to "Power" (Not), "gain" suggest you are using an electrical analogy - this is not helping you.
  41. Lindzen and Choi find low climate sensitivity
    Rw1 - sorry for taking a long time to respond but only intermittent access to internet. "Explain to me how the surface, whose temperature is directly tied to the total power flux via Stefan-Boltzman, is going to 'know' the difference from increased power from Sun or CO2?" It doesnt, I agree, but as I said, 1W/m2 as global annual average has a very different temporal, spatial and spectral distribution for sun versus CO2. The direct radiative balance is obviously maintained but to consider a simplification, 1W/m2 could by say 2W/m2 in one hemisphere and 0 in the other. The temperature response for radiative balance is 0.6 in one hemisphere, 0 in the other still for global average of 0.3. Sensitivity it about feedbacks though. The milankovich forcing driving the ice age cycle is tiny as global average, but the large forcing at 65N over long time delivers feedbacks enough to drive the cycle. The identical forcing at 65S does not - far less scope for feedbacks in the south. You cant do the sensitivity by back-of-the-envelope stuff. You have to run the physics and see how it pans out.
  42. Lindzen and Choi find low climate sensitivity
    co2isnotevil - An additional note on these various forcings and feedbacks: Statistical significance in temperature measurements requires 25-30 years of temperature records to establish a trend, based on the inherent variability of weather (PDO, AO, other influences, clouds, volcanoes, etc.). Your delayed sinusoid feedback responses to cyclic forcings of one year cyclic duration will be completely lost in the noise of the climate. Longer term changes such as CO2 increases and Milankovitch cycles will not.
  43. Lindzen and Choi find low climate sensitivity
    co2isnotevil - In regards to climate sensitivity, please keep in mind that there is not a single 'climate response' with a particular time constant - there are many. Climate response tau's: - Air temperature: hours - Water vapor: week(s) - Northern/Southern temperate snowfall/albedo: months - Ocean surface temperature: weeks/months - Arctic ice cap size: Year plus - Vegetation albedo: Years due to species spread - Greenland ice cap size: 10's of years - Glaciers: Years to 10's of years - Antarctic ice cap: 10's of years plus? - Deep ocean temperature: Decades? Still under investigation - CO2 ocean sequestration/release: months to 100's of years depending on depth. - CO2 rock weathering: 10,000 years plus Yes, for each of these, there will be either a direct response to a sinusoidal forcing cycle (seasons or orbital distance) or, if the forcing is shorter than the response time, a delayed sinusoid - with amplitude decreasing as the response becomes more multiples of the forcing. Note that these responses for different feedbacks will likely not be in reinforcing phase, and may cancel out/reinforce from time to time. On the other hand, a steadily changing trend (such as CO2 forcing) will not cause a sinusoidal response in feedback, but a driven change in the baseline (with weather variability making it non-monotonic). And that's what we see on all of these feedbacks for the CO2 forcing, as evidenced by the temperature record and other data. Cyclic changes don't move the baseline. Non-cyclic changes such our CO2 output do.
  44. Lindzen and Choi find low climate sensitivity
    Chris, The exponential approach to equilibrium is quantified as A*exp(-t/tau), where tau is the time constant, A is the equilibrium value and t is time. Exp(-1) is about 0.37 and 5 time constants, exp(-5), is greater than 0.99. This form of approach to equilibrium arises as the solution to the first order LTI describing the thermodynamic climate system. The related response to a sinusoidal stimulus like exp(-jwt) is a delayed sinusoid whose delay is equal to the time constant for periods larger than 4 or 5 time constants. If we filter the ISCCP data to only those grids over ocean, there is still 1.5C or more yearly variability globally and more than 4C hemispheric specific temperature variability. Equatorial water temperatures are relatively constant, so there is little to no flux between the 2 hemispheres and hemispheric specific heating and cooling tells us exactly how big the planets thermal mass is on a per hemisphere basis. You state that the climate system responds slower than seasonal change. This is clearly wrong because if it was the case, seasonal change would not happen! Just like a capacitor resists a change in voltage, a thermal mass resists a change in temperature and the equations describing this response are nearly identical and the time constants have the same physical significance. Venus has the property you claim relative to the surface, but this is because it's thermal mass is energized CO2 above the surface, while the Earth's thermal mass is primarily ground state water below the surface. While the Venusian 3 degree axis (177 accounting for retrograde rotation) is less than ours, there are no seasonal differences at the surface or even differences across latitudes. There are not even differences between night and day even though the Venusian day is about as long as our year. This is what you would expect from a system with a time constant on the order of years to decades. The Earth behaves in a manner consistent with a short time constant. Regarding the amount of ice that would need to melt to cause a 3C rise, all else being equal, nearly half of the difference between the min and max seasonal snow pack would need to melt. There's just not this much additional ice to melt during the summer! This arises as the incremental reflectivity from the full winter snow pack has about an 7C effect on the surface temperature. This is why the global average temperature in January is 3C cooler, rather than 4C warmer as the increased insolation at perihelion would suggest. This all works out quite nicely when you consider the measured reflectivity variability seen in the ISCCP data.
  45. citizenschallenge at 14:48 PM on 28 December 2010
    Species extinctions happening before our eyes
    nofreewind... hello? i was really curious to hear his come back... hmmm
  46. The Scientific Guide to Global Warming Skepticism
    #45: "Cosmic rays seem to be one of those factors" Eric, I'd love for you to fully explain how that actually works (not how it could work or might work). But it belongs here.
  47. The Scientific Guide to Global Warming Skepticism
    nealjking, I'm not looking for alternative causes for global warming, but I am trying to identify the factors involved in the amplification of CO2 warming. Cosmic rays seem to be one of those factors but there are others.
  48. Lindzen and Choi find low climate sensitivity
    @RW1: "Are you going to argue that the physics of the oceans are different globally then they are hemispherically?" Strawman argument fallacy. That is not at all what Chris is arguing. What he's saying is that, because seasonal changes happen in a relatively rapid cycle (and are balanced between the hemispheres, one being warmer while the other one is cooler), there is not much feedback to the forcing. With CO2, however, the increase is gradual, over decades, which triggers feedbacks that are little affected by seasonal change. Even the direct effect of CO2 is delayed compared to the direct energy transfer caused by insolation. CO2-induced warming takes longer as energy travels back an forth between the GG molecules and the ground. All these comments, and neither RW1 or co2isnotevil (true, it isn't, but increasing it is warming our world) have managed to present a convincing case against a climate sensitivity of 3C.
  49. Lindzen and Choi find low climate sensitivity
    chris, "However the orbital properties of the Earth aren't very relevant to persistent changes in forcings that are fundamental to determination of climate sensitivities. That's because the orbitally-paced sinusoidal insolation occurs more rapidly than the various elements of the climate system can equilibrate with the changing forcings, and thus average out on time scales relevant to establishing the Earth's equilibrium response to forcing." Who is claiming the changing seasonal hemispheric and orbital changing forcings don't average out? They do. The point is that as the forcings change, the climate responds fairly quickly via a significant change in air and ocean water temperature. Are you going to argue that the physics of the oceans are different globally then they are hemispherically? If so, under what law of thermodynamics do smaller, slower increases in thermal forcing take longer than larger, faster increases in thermal forcing to raise the temperature of water to equilibrium?
  50. Lindzen and Choi find low climate sensitivity
    co2isnotevil at 12:42 PM on 28 December, 2010
    "...For example, there is no monotonic trend corresponding to the CO2 trend in the temperature data..."
    Why should one expect such a thing co2isotevil? Attribution of warming trends requires an effort at a realistic assessment of all the contributions to temporal changes in surface temperature. This has been done in detail by scientists. Some useful examples are Lean and Rind (2008) and Hansen et al (2005).

Prev  1993  1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  Next


The Consensus Project Website

THE ESCALATOR

(free to republish)


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