Recent Comments

Prev  2535  2536  2537  2538  2539  2540  2541  2542  2543  2544  2545  2546  2547  2548  2549  2550  Next

Comments 127101 to 127150:

127101. NewYorkJ at 04:34 AM on 20 October 2009
        Empirical evidence that humans are causing global warming
        [ Response: Funny you should mention that, the next post is on that very subject. ] I suppose that the next logical step before discussing feedbacks would be where the approx. 1 C of direct forcing from a doubling of CO2 comes from, although this tends to have much less dispute among already small contrarian circles.
127102. RSVP at 03:17 AM on 20 October 2009
        Empirical evidence that humans are causing global warming
        Riccardo I downloaded and perused the pdf from link... I have to give you credit for providing this reference as matching my earlier remarks. If I understand the report correctly, they are filtering spurious data such as that produced by volcanic eruptions and coming up with temperature profiles of the Earth or regions of the Earth and somehow dissociating human induced climate change. I suppose if you are looking for something you will find it, and if not, keep mounting the voodoo until you do.
127103. PeterPan at 22:03 PM on 19 October 2009
        There's no empirical evidence
        Loads of thanks, and good new article! We have a rather good grasp of the current climate system. The only thing that has change enough to warm the planet is GHG (mainly CO2) and all the observations are consistent with that. Some people still insist that there might be some misterious unknown thing doing it (and some other unknown thing cancelling out the CO2 warming effect) even though there isn't any evedence at all. It seems incredibly twisted to me. It is false that there has been no warming during the last ten years. Why do you cherrypick CRU instead of GISS, Rick? Do you just choose the sources that fit your bias?: http://www.realclimate.org/index.php/archives/2009/10/a-warming-pause/ What happens if you begin one year earlier or later? A remarkable change in your trend? That's why your 10-year trend is not significant, and that's why 30-year trends are significant, because they don't change much if you add or remove some years: http://moregrumbinescience.blogspot.com/2009/01/results-on-deciding-trends.html Are short-term cooling trends unusual under the current global warming? No: http://tamino.wordpress.com/2009/06/26/breaking-records/ http://www.agu.org/pubs/crossref/2009/2009GL037810.shtml If you want to disprove global warming just on a statistical basis you will need more than a statistically insignificant short-term cooling trend.
127104. Robbo the Yobbo at 21:37 PM on 19 October 2009
        Empirical evidence that humans are causing global warming
        Riccardo, The idea of climate shifts is not speculative at all. What Swanson and Tsonis did was use a (undefined) numerical scheme involving long term records of global ocean and atmospheric indices to identify historical climate shifts. They did this instead of eyeballing them in from the graphs. These ocean/climate state shifts occurred in the mid 1940's, the mid 1970's and around the turn of the millennium. Other people have for decades been wondering what happened in 1976 to 1977 in the Pacific Ocean - the ‘Great Pacific Climate Shift' – and whether this was natural or not. That it seems to have turned around again strongly suggests a natural component. There are also decadal changes at the poles and in the Atlantic. I don't think Swanson and Tsonis add much to the science - but they are useful in providing another perspective - and one that even passes the realclimate test. I don't think those guys have more than a passing acquaintance with empirical oceanographic and hydrological science. As a proposed causal mechanism - Swanson and Tsonis posit a synchronous chaotic dynamic ocean system – i.e the states in the global ocean synchronise, have a hissy fit and shift into an alternate state. A mechanistic interpretation. I simply don’t think it’s so but is externally forced by radiative changes associated with variation in Earth albedo. What Swanson and Tsonis 'hypothesised' was: 1. that the trend between 1979 to 1997 was the residual warming trend when climate shifts are excluded - if you look at the trend line at the Swanson real climate blog - it is about 0.1 degrees C/decade; 2. that the current cool mode ocean/climate state could persist for 2 to 3 decades – as they have in the past. Swanson and realclimate characterise this as ‘warming interrupted’ – I think this depends on whether the ACRIM-PMOD or ACRIM-TSI trend for recent total solar irradiance is the more correct result. Regardless, the residual surface warming trend identified (0.1 degree C/decade) for recent warming is about correct - regardless of wehether this results from internal heat transfer between the ocean and atmosphere or is externally forced. If internal - the oceans should continue to warm in the current cool SST mode and the atmosphere cool. If external - the oceans should cool as well. As I say - I think the balance of probability favours external forcing. I have never intended to prove that carbon dioxide is not a greenhouse gas. The idea is that the climate states alternately augment and mask AGW as you suggest. But you cannot look at most recent augmented mode and conclude reasonably that all of the warming in the relevant period is AGW. The climate shift in the Pacific results not only in a cool and warm mode PDO’s – but in Pacific wide changes involving modulation of the frequency and intensity of ENSO events. A cool mode, such as we are now experiencing, has fewer and less intense EL Niño and more frequent and intense La Niña – statistically and hydrologically speaking. The Australian hydrological connection is best characterised in work by Stewart Franks but there are also global hydrological teleconnections of course. The idea of Ocean/climate state shifts has developed in the past decade – but they are based on long term empirical research and provide a reasonable working hypothesis for the lack of surface warming in the past decade. Cheers Robert
127105. Dan Pangburn at 21:37 PM on 19 October 2009
        It's a 1500 year cycle
        That is the point. As the paper shows, increased greenhouse gases did not contribute significantly to global warming. The methodology and links to the source data (all measured) are given. Do the exercise yourself and discover that many (not all) Climate Scientists have made an egregeous mistake and a lot of people have been misled.
127106. Riccardo at 19:35 PM on 19 October 2009
        Empirical evidence that humans are causing global warming
        Robbo, the concept of climate shift by itself is speculative. You should note the words used by Swanson, "We hypothesize" and "If this hypothesis". So you should not take climate shifts as given. But even if it will prove to be true, the overshoot is identified in 1998. Before that the trend was roughly 0.2 °C/decade while the full trend up to 2008 is 0.15 °C/decade. Is this you're claiming? And is this that eventually disprove agw or the effect of CO2 forcing? And what about this shifts that produce an overall upward trend and not simply ups and downs averaging to zero in the long run? What is responsible for this? Could it be that this shifts just modulates the average upward trend, as Swanson indeed suggested?
127107. Robbo the Yobbo at 17:54 PM on 19 October 2009
        Empirical evidence that humans are causing global warming
        G'day Steve, My exact position is no warming for 20 to 30 years from 1998. There is no substantive difference between the Swanson quote above and this statement. Indeed it is consistent as well with the Keenlyside et al study in which Latif participated. Not sure what the problem is with the concept of shifts in ocean/climate states – all I get responses with nil substance to the effect that – nah – it just ain’t so. Yet these shifts are evident in the 100 year plus records of surface and ocean temperature and in hydrological regimes. Temperature variation in the Arctic shows an exaggerated response to variation in global temperature – strong decadal variation is apparent in any of the surface temperature records – and I linked to the IARC at Fairbanks Alaska for support. This is also interesting – there were shifts in temperature in Alaska of 3.1 degrees centigrade as a result of the 1976 climate shift. Hartmann, B., and Wendler, G. 2005: The Significance of the 1976 Pacific Climate Shift in the Climatology of Alaska. J. Climate, 18, 4824–4839. ‘The influence of the shift in Pacific Ocean variability on temperature is more pronounced in the continental regions of Alaska (south-central, interior, and west) than in the maritime regions (southwest and southeast). The Arctic, while it showed some response, is most likely governed more by Arctic variation (i.e., the Arctic Oscillation), and the interplay of Pacific and Arctic circulation variation and its effect upon Alaska is a possible subject for further study.’ The Arctic Oscillation is another example of multidecadal variability – albeit with a familiar periodicity – positive since the mid 1970’s and peaking in the late 1990’s. I am quite willing to revise my views if 100 years of ocean and hydrological science is suddenly reversed. But see no reason to do so while the world is currently not warming. Cheers Robert
127108. opaque at 13:46 PM on 19 October 2009
        It's the sun
        Although it is somewhat speculation, lead may have offset warming from 1940 to 1980 and therefore the links between global temperature and sun activity could be weaker then expected http://www.newscientist.com/article/dn16976-did-lead-cause-global-cooling.html Sorry i cant find the actual paper this has been published in. I'm posting this for debate not because i sincerely believe there is a direct correlation here
        Response: The paper is Inadvertent climate modification due to anthropogenic lead (Cziczo 2009). Thanks for the link - an interesting paper. I wonder if it'll have any impact on our understanding of mid-century cooling.
127109. Steve L at 13:02 PM on 19 October 2009
        Empirical evidence that humans are causing global warming
        Robbo: "The Arctic should, like the rest of the planet but more strongly, cool over the next couple of decades." It's fun to watch you on the various threads claim something and then get caught by Chris in a fib and then have to step backward. But don't step back on your claim that I've quoted above. I want to bet you on it, and I'll give you good odds.
127110. Dan Pangburn at 12:44 PM on 19 October 2009
        It's a 1500 year cycle
        The evidence that average global temperatures measured for the entire 20th century and to the present actually are a natural cycle with no influence whatsoever from carbon dioxide is shown at http://climaterealists.com/index.php?tid=145&linkbox=true. There is no Anthropogenic Global Warming (AGW) (and therefore no ACC) from added atmospheric carbon dioxide. It is a mistake to believe that there is.
        Response: The paper (written by Dan Pangburn) you link to (here's a direct link to the PDF) proposes that just the effects of the Pacific Decadal Oscillation (PDO) and solar activity are sufficient to explain temperature trends over the last 130 years. This argument is fundamentally flawed. Over the past 50 years, the planet has been in positive energy imbalance. Globally, oceans have been accumulating heat.
        
        PDO is an ocean cycle that causes internal variability, where heat is exchanged between the ocean and atmosphere. The PDO cannot explain the strong energy imbalance. Changes in solar activity do affect the planet's energy imbalance but over the last 50 years, the sun has showed a slight cooling trend.
        
        Lastly, we have experimental observations confirming an enhanced greenhouse effect due to CO2 and CH4. Pangburn's explanation fails to explain what's happened to all the warming caused by increased greenhouse gases.
127111. batsvensson at 11:42 AM on 19 October 2009
        Empirical evidence that humans are causing global warming
        Respond to respond in Post #31: I am not conceding anything, I am merely reacting to the, for me, obvious fact that the OP are using positive confirmation to led something in evidence and furthermore has failed to show that hypothesis of the form "IF humans release CO2 THEN there exists no global warming" are false. In this I assume the OP is aware of that condition not only must be sufficient but also necessary.
127112. Robbo the Yobbo at 11:16 AM on 19 October 2009
        Empirical evidence that humans are causing global warming
        Let's make this even clearer for Chris and Riccardo - The climate shifts occured in 1976 to 1977 and 1999 to 2001. The 1998 El Nino was said to be a big climate 'overshoot which is radiatively dissipating.' It is not part of the greenhouse gas signal - but an aspect of what is widely referred to as climate shifts. The causes of climate shifts are hugely speculative - so take any statement with a pinch of salt - but they appear in all sorts of climate records. The greenhouse signal is in the temperature record from 1977 to 1997. This is 1/2 of the total warming between 1976 and 1998. There are many other factors in there as well - black carbon, methane, solar irradiation, tropospheric ozone warming etc. Insistence that AGW is 0.2 degree C/decade is unsustainable.
127113. Robbo the Yobbo at 08:01 AM on 19 October 2009
        Empirical evidence that humans are causing global warming
        Chris Schuckmann calculated heat content to 2000m. Heat content at lower levels might become important at some time. However, there is no possibility of comparison with other methodologies. Everyone else is finding no to minimal warming to 700m - although even then they are not consistent with each other. Should the planet be warming - Here is Kyle Swanson quoted verbatim from at real climate - http://www.realclimate.org/index.php/archives/2009/07/warminginterrupted-much-ado-about-natural-variability/ 'What’s our perspective on how the climate will behave in the near future? The HadCRUT3 global mean temperature to the right shows the post-1980 warming, along with the “plateau” in global mean temperature post-1998. Also shown is a linear trend using temperatures over the period 1979-1997 (no cherry picking here; pick any trend that doesn’t include the period 1998-2008). We hypothesize that the established pre-1998 trend is the true forced warming signal, and that the climate system effectively overshot this signal in response to the 1997/98 El Niño. This overshoot is in the process of radiatively dissipating, and the climate will return to its earlier defined, greenhouse gas-forced warming signal. If this hypothesis is correct, the era of consistent record-breaking global mean temperatures will not resume until roughly 2020.' Unless Swanson has changed his mind in the past 6 months - the underlying forced rate of warming is less than half of the total 1976 to 1998 warming. Take climate shifts out of the record and warming due to greehouse gases is less than 1/2 of warming between 1976 and 1998. Radiative imbalance is not constant nor linear. I have referred you to Project Earthshine before - again - there is a decrease in shortwave radiation between 1999 and 2008 of 2W/m2. There is no magic but the heat budget of the planet changes on decadal timescales. Latiff said that the difficult questions about multidecadal variability should be asked. The rest of the video confuses interannual with multidecadal variation. Typical clutching at straws.
127114. PeterPan at 07:20 AM on 19 October 2009
        Is Antarctic ice melting or growing?
        Update: "the mass loss increased from 104 Gt/yr in 2002–2006 to 246 Gt/yr in 2006–2009, i.e., an acceleration of −26 ± 14 Gt/yr2 in 2002–2009" http://www.agu.org/pubs/crossref/2009/2009GL040222.shtml PDF: http://thingsbreak.files.wordpress.com/2009/10/increasing-rates-of-ice-mass-loss-from-the-greenland-and-antarctic-ice-sheets-revealed-by-grace.pdf
127115. PeterPan at 06:50 AM on 19 October 2009
        There's no empirical evidence
        I think that this post was different in the past and included a list with some fingerprint evidence (rise of the tropopause, expansion of the hadley cell...) with links... Where can I find this?
        Response: Yes, sorry about removing that information. As I added in more info to this page, I simplified the presentation lest it get too long and unwieldy. So I've temporarily removed all the other bits and pieces until I get organised and restructure it to a subpage somewhere. In the meantime, here is other evidence of warming:

        • Surface weather station measurements
        • Satellite measurements show that the troposphere is warming
        • The stratosphere is cooling as predicted by anthropogenic global warming theory (this cannot be explained by solar variability)
        • Temperatures at the ocean surface and at various ocean depths show warming as far down as 1500 meters
        • Sea level rise
        • Gravitometric measurements of Greenland and Antarctica show net ice loss
        • Sea-ice loss in the Arctic is dramatically accelerating
        • Acceleration of glaciers in Greenland and Antarctica, particularly within the last few years.
        • The rise of the tropopause
        • Poleward migration of species
        • Increased intensity of hurricanes as expected from rising sea surface temperatures
        • Accelerating decline of glaciers throughout the world
        • Rise in temperatures at greater depths in the permafrost
        • Rapid expansion of thermokarst lakes throughout parts of Siberia, Canada and Alaska
        • Changes in ocean circulation as predicted by climate models, for example, with temperatures rising more quickly overland
        • Disintegration of permafrost coastlines in the arctic
        • Changes in the altitude of the stratosphere
        • An energy imbalance - the earth is receiving more energy than it emits (Hansen 2005)
        • Poleward movement of the jet streams (Archer 2008, Seidel 2007, Fu 2006)
        • Widening of the tropical belt (Seidel 2007, Fu 2006)

        Note - as you say, some of the evidence listed above are unique to CO2 warming - the carbon "fingerprint".
127116. shawnhet at 06:24 AM on 19 October 2009
        How we know global warming is still happening
        I don't think it is accurate to say I am the only one who thinks it unlikely that all changes in cloudiness in recent years are a product of feedback from teperature changes. You can try a Google search of Earthshine and albedo if you like. Cheers, :)
127117. chris at 05:54 AM on 19 October 2009
        Empirical evidence that humans are causing global warming
        Re #24 Poor old Robbo….you keep on saying things that are simply untrue, and attempt to “recruit” science that simply doesn’t support your notions. Keenlyside and Latif, who you want to think support your notion of “cooling influence in the atmosphere and oceans that lasts for 20 to 30 years”, in fact predict a particularly large warming of around 0.5 oC in the period 2010-2030; see Figure 4 of: N. S. Keenlyside, M. Latif, J. Jungclaus, L. Kornblueh & E. Roeckner (2008) Advancing decadal-scale climate prediction in the North Atlantic sector Nature 453, 84-88 So you can’t use these scientists in support of a notion to which they have recently published an entirely contrary projection. Why keep restating what you know is a falsehood Robbo? Likewise your notion that Tsonis and Swanson consider that “at least half of recent warming between 1976 and 1998 was the result of the most recent warm ocean mode”, is another untruth, since we can inspect their analysis of the contribution of ocean circulation effects on surface temperature variability, and find that they consider that ocean circulation effects have made only a small contribution to late 20th century warming (likely no more than around 0.1 oC; i.e. nowhere near half), and essentially zero contribution to the overall warming of the 20th century. That’s not really surprising since the ocean circulation cannot “magic up” heat from nowhere..they merely redistribute the heat in the oceans: see Figure 3 of: Swanson KL, Sugihara G, Tsonis AA (2009) Long-term natural variability and 20th century climate change Proc. Natl. Acad. Sci. USA 106, 16120-16123 Your ad hominem at Schuckmann is ignorant; it's based on a misunderstanding of heat uptake, ocean currents and surface temperature measures. One can have relatively constant heat uptake into the ocean under a radiative imbalance, while having cyclic or stochastic ocean circulation effects on surface temperatures. Schuckmann et al is completely compatible with independent measures of radiative imbalance and other consequences in the natural world. Incidentally, for those like Robbo who might consider that “claiming that Latiff (sic) was misrepresented …is very, very silly”, the following video in which we can hear Dr. Latif’s words as he speaks them indicates rather categorically that pointing out the simple fact that he was (rather amusingly if it wasn’t a serious subject) misrepresented, isn’t “silly” at all: http://www.youtube.com/watch?v=khikoh3sJg8
127118. batsvensson at 05:29 AM on 19 October 2009
        Empirical evidence that humans are causing global warming
        To the OP: My remark was to draw attention to the fact that it does not follow from the premises, "CO2 is greenhouse gas", etc that "human release CO2 is the causes of temperature changes". The "conclusion" is not a conclusion but a separate statement that need a separate chain of evidence. Those evidence are not presented in the article, nor in the additional references given.
        Response: So you will concede that CO2 causes an enhanced greenhouse effect and the planet is accumulating heat? But not that an accumulation of heat causes global temperature to rise?
127119. Riccardo at 04:26 AM on 19 October 2009
        Empirical evidence that humans are causing global warming
        RSVP, i don't know exactly what you mean by "unstable", but i'd probably agree. It's the timescale and the causes that are different. Back to the issue of the analisys of the temperature trend you (and other people too) might be interested in this article due to appear in J. Clim.
127120. RSVP at 03:31 AM on 19 October 2009
        Empirical evidence that humans are causing global warming
        Riccardo, I dont know what "conclusions" you are referring to, but now that you mention it, the historical data appears to indicate that the Earth's climate is pretty unstable with or without mankind's "help". (Sorry for not being able to point to url for substantiating that thought.)
127121. Riccardo at 02:46 AM on 19 October 2009
        Empirical evidence that humans are causing global warming
        RSVP, you should invest much more than 15 seconds in reading after an easy google search. Especially when history is concerned you can't just pass by and come so superficially to unfounded conclusions; read carefully. A couple of quotes from your second link: "With just one more degree Celsius of warming, it'll be hotter than ever in the last million years. In other words, we may be witnessing the end of the whole cycle of ice ages!" We're almost there and in mere century or so. "Of course, 1 Celsius ain't much compared to the 15°-20° Celsius cooling throughout the Cenozoic - but it's happening fast, and and it's not over yet! With all the changes the Earth has experienced over its history, one might think one more change is no big deal. In the long run, yes. But the future of humanity depends crucially on what happens in the "short run": the next millennium or two. If we didn't mess around with the climate, our Earth's climate might remain stable for another thousand years or more. As it is, we're bringing on more sudden changes." And this is the conclusion after 65 milions years of history of earth climate. Finally, you question (Where do you draw the line in terms what is acceptable and inacceptable?) is a very important one for the choices that are to be made. To answer, though, one needs to accept the science in first place. After that it's more a political than scientific issue, a tough one indeed. You have to decide the level of damage people have to suffer and who is going to pay. I would not to be in Copenhagen in December ... :D
127122. batsvensson at 22:53 PM on 18 October 2009
        Empirical evidence that humans are causing global warming
        The problem I see with this article is that it uses the argument "guilt by association". The conclusion that human release of CO2 causes global warming does not follow from the factual observation that atmospheric CO2 levels and global temperature changes are corresponding in time. The second problem I see is that the OP uses positive confirmation to prove the thesis to be correct. However, Popper has taught use that we can only use falsification if we want to investigate something scientifically, and that we only can assign a certain confidence level to our knowledge, not a definite truth. Therefore, to strengthen the confidence in the thesis one should instead focus on falsifying other explanations not confirming a particular thesis. What gives us confidence in CO2 as being the agent for increase in global temperature? The foundation for claiming CO2 to be the agent is based on computer simulated climate models, but there are no definite empirical evidence or experiment so far that has singles out CO2 as the major agent. On the contrary there are evidence from observational data to support the interpretation that CO2 can not be a causal agent. What we know so far from empirical evidence is that those agent that has been investigated until now has not been good enough candidates to be singled out as The Agent of cause, not even CO2. Therefore one may take a step back and start to look over other things and ask oneself the question what we may have missed so far. And this is being done by the scientific community by investigating alternative explanations, but to ridicule this as "skeptic attitude" is to misinterpret the scientific way of approaching a problem. A "skeptic attitude" is a necessary condition to make progress in scientific understanding. Because it is used to exclude other possible explanation – not to prove an explanation. A scientific methodical oriented mind need always to ask them self the question "What if I am wrong?" Knowing this but still claiming that CO2 is the agent is equal to claim that the computer climate models describes the climate with sufficient parameters – in other word that is to claim that the computer models holds the ultimate Truth in this question. The OP asked if this is arrogant to claim - the reader may judge by them self.
        Response: I can only assume that you didn't actually read the article above. I explain in (what I hoped were) easy to understand terms the causal link between more CO2 and an enhanced greenhouse effect (aka warming). I outline the direct measurements that confirm that the enhanced greenhouse effect is actually happening. If you're genuinely interested in learning more about the evidence for CO2 warming, I go into more detail here.
        
        The whole point of this article is to emphasise that the evidence for CO2 warming is not based on climate models but on definite empirical evidence. Please read the article above then peruse the experimental evidence for CO2 warming (and I recommend following the links to read the actual research papers cited).
127123. RSVP at 22:50 PM on 18 October 2009
        Empirical evidence that humans are causing global warming
        Riccardo Investing 15 seconds on a Google search, I found these two links among others http://www.scotese.com/climate.htm http://math.ucr.edu/home/baez/temperature/ both contain graphs that I assume are based on some science, showing that the planet's temperature has "forever" been changing with excursions of about 15 C peak to peak. If anyone wants to make a meaningful statement about man-made global warming, I would think as a minimum requirement that they would need contrast statistically the observed modern trends with this data and clarify how these are dissociated. This issue aside, given all the controversy, it would appear that a definion of "global warming" is wanting, given an understanding that theoretically, all human physical activities add some heat to the planet. Where do you draw the line in terms what is acceptable and inacceptable? I suspect that circular logic is at play here, since the implicit definition indicates that heat generated by greenhouse gases is inacceptable.
127124. Riccardo at 18:56 PM on 18 October 2009
        Empirical evidence that humans are causing global warming
        Robbo same old (and boring) skeptic attitude: assume what people think, claiming that people (_all_ indeed) said what you would like them say. Is there anyone denying the very existence of variability? I bet no. But you insist just to give yourself the right to say that my claim was foolish, and of monumental proportions ... There's no point at all to post offtopic on this issue for one more reason, variability do not rule out the background trend but is just suprimposed on it. You should be aware that decadal and multidecadal variability alone cannot explain recent temperature trend, as Latif that you quote continues to repeat over and over ... On the contrary, even a simple linear trend added to ENSO-PDO effect (plus volcanoes eventually) accounts for most, almost all indeed, of the temperature record including variability.
127125. Robbo the Yobbo at 14:27 PM on 18 October 2009
        Empirical evidence that humans are causing global warming
        Douglas and Knox looked at periods of radiative imbalance in the light of the multidecadal ocean/climate states - they say that the radiative imbalance changed again with the climate shift in 2000 to -0.2 W/m2. The best argument for a natural origin of decadal climate shift is the shift in climate after 1999. The difference between Schuckman and Douglas is 1 W/m2. There is obviously no agreement. There is also no agreement of Schuckmann to the OHC data at the National Oceanographic Data Center. The Douglass graph you show stops at the most recent climate shift. You certainly can't have read the paper - or even the blog - to come to the conclusion you have. Abstract Ocean heat content and Earth’s radiation imbalance D.H. Douglass and R, S, Knox Dept. of Physics and Astronomy, University of Rochester, PO Box 270171, Rochester, NY 14627-0171, USA Earth’s radiation imbalance is determined from ocean heat content data and compared with results of direct measurements. Distinct time intervals of alternating positive and negative values are found: 1960–mid-1970s (−0.15), mid-1970s–2000 (+0.15), 2001–present (−0.2 W/m2), and are consistent with prior reports. These climate shifts limit climate predictability. The recent change to a -ve radiative imbalance is certainly in line with observations of Earth albedo since 1999. Google Project Earthshine and look at the most recent additions to the bibliography. The PDO is not the cause of anything - but is in itself one outcome of 20 to 30 year global ocean states. There is a 100 years of science on this in both the Atlantic and Pacific and thousands of papers. Don Easterbrok, Pielke Sn, Bob Carter, Roy Spencer and Stewart Franks – amongst many others - have been discussing this for a decade. How this must rankle. Keenlyside has been talking about multidecadal Atlantic influences on global surface temperature for years. Recently Kyle Swanson and Anastasio Tsonis used a numerical method to analyse for shifts in ocean/climate states. They found what was evident for many years from eyeballing (that is, after all, what they are for)the ocean indices graphs. The mid 1940's, the mid 1970's and 1999/2001 are the most recent climate shifts. At least half of recent warming between 1976 and 1998 was the result of the most recent warm ocean mode. We are now in a cool ocean mode - a cooling influence in the atmosphere and oceans that lasts for 20 to 30 years from the last climate shift around the change of the millenium. The IARC is based at the University of Alaska at Fairbanks. I linked to ICECAP to find a nice summary - but by all means link to the IARC directly and search for decadal changes. http://www.iarc.uaf.edu/ If you look at any Artic temperature reconstruction - you will see very pronounced decadal temperature variation. A peak in the 1940's and a recent peak around 2000. There are some temperature anomalies here for instance - http://icecap.us/images/uploads/RECENT_RESULTS.pdf The satellite sea ice anomalies referred to are not of sufficient record length to capture decadal variability. The satellite record doesn’t give enough information to draw meaningful conclusions at this time. The Arctic should, like the rest of the planet but more strongly, cool over the next couple of decades. ‘Multidecadal fluctuations in the Arctic/North Atlantic climate system should be taken into account when assessing long-term climate change and variability. Understanding the key mechanisms influencing the Arctic/North Atlantic multidecadal variability is essential for developing robust climatic forecasts.’ Schuckmann et al is utter rubbish because they – like most people around the world – have not come up to speed with multidecadal ocean/climate shifts. Mojib Latiff said that asking the uncomfortable questions about climate variation was needed lest the questions be asked by less forgiving people like myself. Simply claiming that Latiff was misrepresented – by a right wing journal such as New Scientist for God’s sake – is very, very silly. Clinging to denial of multidecdal ocean/climate states would be foolishness of monumental proportions. It is not suggested that carbon dioxide is not a greenhouse gas - simply that most of the recent warming between 1976 and 1998 was due to natural climate shifts - and all of the current cooling. Do you have another explanation for current cooling? Didn't think so. Ocean heat content is the best way of monitoring for radiative imbalances - but you have to expect that this is not constant nor linear - and none of the researchers - as Susan Wijfells said last month - agree with each other as yet. Obviusly - more development in methods is needed.
127126. Philippe Chantreau at 11:11 AM on 18 October 2009
        How we know global warming is still happening
        The "unlikely" part is entirely your opinion. Scientists studying the question, such as Trenberth and Fasullo don't find it so unlikely. The only physical reason to expect increased nebulosity is a constant relative humidity and even that is not entirely certain. If relative humidity shows a slight decrease, who knows?
127127. batsvensson at 09:46 AM on 18 October 2009
        Empirical evidence that humans are causing global warming
        Thumb, "this sounds like me saying my stove top surface actually cools because it's loosing energy as it radiates heat." That is pretty much a correct observation otherwise you stove would melt pretty soon. If something radiates energy, then it is a cooling phenomena per definition.
127128. wanderers2 at 06:55 AM on 18 October 2009
        Are humans too insignificant to affect global climate?
        Thank you for a well-designed, thoughtful and informative website. In particular I REALLY appreciate the links to the primary literature (e.g., Ghosh 2003), which is often hard for non-specialists to find. Please keep it up! Andrew (a practicing ecologist) P.S: Regarding comment #26. There is nothing wrong with the Y-axis scale used in Figure 1, as it fairly represents the variability in the observed data. Plotting from a zero origin would be meaningless unless one wanted to minimize the visual impact of the trend.
127129. shawnhet at 04:59 AM on 18 October 2009
        How we know global warming is still happening
        Yes, Philippe I agree that **if** on assumes that all changes in overall cloudiness are a result of a feedback on temperature change, then recent history would tend to argue for positive cloud feedback. However, there is no reason that all recent changes in clouds are a result of feedbacks on temperature(and this seems unlikely). There are, OTOH, some pretty good basic physical reasons for assuming that cloud cover will increase or at least stay the same in a warming climate(more condensing water available to form clouds). Cheers, :)
127130. Philippe Chantreau at 02:59 AM on 18 October 2009
        Empirical evidence that humans are causing global warming
        International Arctic Research Center? What the heck is that now? Is it the name D'Aleo gives his site these days? Seems to imply it's doing real research so I would have expected better than a blog post. On the other hand, looking at Cryosphere Today, we see that the current global sea ice anomaly is about -1.75 million sq km. The last time that there was a positive anomaly of comparable magnitude was late 1988. http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/global.daily.ice.area.withtrend.jpg
127131. Riccardo at 00:53 AM on 18 October 2009
        Empirical evidence that humans are causing global warming
        Robbo the Yobbo, "Continued neglect of the obvious and the evident - is just very, very silly." I completeley agree with you, but you need to modify the claim "This is consistent with both the evidence of past multidecadal changes and the expectation of a cooling influence for 20 to 30 years form 1998" in "This is consistent with both the evidence of past multidecadal changes and an almost linear underlining trend" So yes, it's silly to neglect that decadal variability alone _cannot_ do the job. One last thing: "expectation of a cooling influence for 20 to 30 years form 1998" could you please explain? I've never heard such a claim from a scientist, apart from the blatantly misinterpreted Latif words reported across the web.
127132. Robbo the Yobbo at 15:28 PM on 17 October 2009
        Empirical evidence that humans are causing global warming
        I will link also to the International Arctic Research Centre http://icecap.us/images/uploads/RECENT_RESULTS.pdf Continued neglect of the obvious and the evident - is just very, very silly.
127133. Robbo the Yobbo at 14:04 PM on 17 October 2009
        Empirical evidence that humans are causing global warming
        Both surface temps and ocean heat content vary on annual to multidecdal (to indeed millenial plus) timescales. The Schuckmann paper shows modest warming from 2003 to 2008. However, the result is strongly dependent on the state of ENSO at start and end dates. The ocean is currently a little cooler in the information provided by the NOAA National Oceanographic Data Center (NODC). http://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/ There is no strong warming evident in the past 6 years. This is consistent with both the evidence of past multidecadal changes and the expectation of a cooling influence for 20 to 30 years form 1998. There is nothing difficult or controversial in this - climate changes - and sudden climate shifts - occur naturally and obviously. This makes any climate prediction problematic and the 'radiative equilibrium' models utterly nonsensical. http://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/ The radiative imbalance is not constant. Until there is a better understanding of natural variations in climate - the attribution of recent warming to AGG is pointless and misguided. The radiative equilibrium model of atmospheric physics is and always has fundamentally flawed - based as it is on a flawed assumption of solar and Earth albedo constancy. http://www.sciencedirect.com/science?_ob=ArticleURL... http://wattsupwiththat.com/2009/08/11/ocean-heat-content-and-earth%E2%80%99s-radiation-imbalance/ Use of the ohc paper by Schuckmann et al to assert continued gloabl warming is misguided.
        Response: The Douglass paper you link to looks at the planet's energy imbalance and finds it has increased from the 1970's to present:
        
        
        
        They argue that there's a correlation between energy imbalance and the Pacific Decadal Oscillation. But there is no causation. On the other hand, the causation between CO2 and energy imbalance is proven by multiple lines of empirical observations.
        
        Note, using Schuckmann to assert an energy imbalance doesn't contradict Douglass's results either - they do exactly the same thing - use ocean heat to find a positive energy imbalance.
127134. Philippe Chantreau at 10:23 AM on 17 October 2009
        How we know global warming is still happening
        The physicsworld.comn piece referenced by RSVP is not a research article but rather an opinion piece. Besides reminders that water vapor is the chief GH gas and CO2 the chief cause of recent increased GH effect, it considers water vapor feedback. It postulates that, with increased cloud cover, the WV feedback may not be as strong as current models show. However, let's not forget the information provided by your fellow skeptic Robbo. Both the Clements paper and the Trenberth and Fasullo paper that he trumpeted with great fanfare suggest decreased lower cloud cover as a feedback to enhanced GH effect. Your own reference to increased NPP in the Amazon due to increased insolation seems to agree. As I said, it may not be all that simple. Cheers.
127135. mr_walsh at 10:14 AM on 17 October 2009
        Models are unreliable
        Good science predicts the future. We know enough about biology to know that what we can to do grow more food; and we bet our lives on that...if that science let us down one year, we'd starve in our modern society that depends on optimum agriculture. We know enough about cars to know that all our cars will start and get us home tonight when we leave work. We aren't afraid as we approach other cars at alarming rates because science guarantees brakes and tires do predictable things. We know that if we dump lead into rivers the lead gets into fish and human tissue and causes terrible consequences. We can bank on this being true today as well as 1000 years from now. *That* science is done. But the science of climate modeling is certainly *not* done, at least in the minds of most people. Let's face it; we are talking very tiny numbers - .038% CO2, < 0.2 degree temperature deltas. We are asked to believe that while human emissions are small compared to natural ones, that the earth absorbs *exactly* the amount it emits, and so any tiny perturbation is a disaster. Hogwash. There was a time where the orbits of the planets were explained by invisible crystal spheres. And they have models too - ones that would even explain the retrogradation of Mars - all of which functioned using the inviolate assumption that Earth was the center of the visible universe. That premise drove the model - which, while far from elegant - was made to work. Here we are in the same situation. I have to believe that climate researchers have an agenda. People who don't believe in AGW are certainly not going to devote their lives to studying it. And so, we start with one premise - it's all our fault - and work from there. When an objection comes out - say to the magnitude of CO2 and man's contribution to that - out come the curves. Out come the crystal spheres. Out come the graphs showing tiny variations drawn on an offset scale for emphasis. Out comes a vague paper digestable by 'the community' but no one else. If you truly want people to believe that "the science is done", do some actual physical research. Create a large enclosed simulated atmosphere and show the effect of doubling CO2. Don't slip away saying it's not that simple. Science is all about reduction to experiments that *are* that comprehensible. Otherwise, the models are about as believable as those that can model old stock market data but won't make a dime.
127136. WAG at 07:11 AM on 17 October 2009
        Empirical evidence that humans are causing global warming
        To me, you don't even really need to quantify the exact impact of CO2 on temperature to believe we will suffer major consequences from rising CO2. If you accept that CO2 has SOME impact on temperature (which even the most ardent skeptics do), the only thing you need to know is that CO2 is already at its highest level in 400,000 years, and probably in 15 million - and it's poised to double. There's simply no conceivable way we can pump that much CO2 into the atmosphere without SOMETHING drastic happening. Here's my Blog Action Day post, via Coby: http://scienceblogs.com/illconsidered/2009/10/blog_action_day.php
127137. Philippe Chantreau at 06:49 AM on 17 October 2009
        Are humans too insignificant to affect global climate?
        Your denialist fello must be a fan of John Daly, whose graphs feature highly compressed Y axises in order to downplay recent warming. I guess it is probably a widespread convention among some that graphs should be adjusted to show what they want to see instead of revealing what the data say.
127138. rlasker3 at 03:26 AM on 17 October 2009
        CO2 effect is saturated
        What I don't understand about this argument is that we have a clear demonstration of what high levels of CO2 can accomplish in respect to greenhouse effect with Venus. From what I understand Venu's atmosphere is over 95% CO2 and it's surface tempuratures are almost 500 degrees celcius. That makes it hotter than Mercury the closest planet to the Sun. If CO2 had a saturation point wouldn't Venus have reached it or am I totally misunderstanding the premise?
127139. Ned at 02:11 AM on 17 October 2009
        Empirical evidence that humans are causing global warming
        There are two ways you can raise the water level in a lake. You can increase the flow of water from the lake's inlet, or you can decrease the drain of water through the lake's outlet. Likewise, the heat content of the climate system (atmosphere, oceans, and land) is ultimately determined by the balance between energy input (shortwave radiation from the sun) and energy output (longwave radiation from the earth out into space). CO2 in the atmosphere reduces the flux out of the system and increases the heat content of the system. Eventually, a new equilibrium is reached, where the outgoing longwave flux once again matches the incoming shortwave flux, but at a higher level of heat content of the climate system.
127140. rlasker3 at 00:51 AM on 17 October 2009
        Empirical evidence that humans are causing global warming
        If you want empiracle evidence of the saturation level of CO2 then look no further than Venus. It has an atmosphere which is over 95% CO2 and surface tempuratures are at 467 degrees celcius hotter than the surface of Mercury. Seems we still have a long way to go before reaching that saturation level.
127141. Riccardo at 23:59 PM on 16 October 2009
        Empirical evidence that humans are causing global warming
        RSVP, I just was less patient the the other mates here; just read their replies. But to male my point clearer, i'll give you an example of one of your trivial but wrong reasoning. If you take away heat from a body, it will cool; this is the trivial part. But if you apply it to the earth surface and the atmosphere alone it's plain wrong.
127142. WeatherRusty at 23:41 PM on 16 October 2009
        Empirical evidence that humans are causing global warming
        RSVP, If I read your post #4 correctly, you seem to be implying that the greenhouse effect violates the laws of thermodynamics. In your summation you said: "remember that you cant get something for nothing, because if you could, we could solve the energy crisis by simply building greenhouses in our backyards." I believe you think this way because you regard the energy emanating from the Earth's atmosphere to be the primary source. The Sun is the primary source. The flow of energy is a two way street, a net warming on average during daylight hours and a cooling at night. However, the cooling loss of energy is also occurring during the daylight hours, it is ongoing day and night. And nothing is "trapped"..bad choice of words in common usage to describing what is happening, leading to all kinds of misconceptions. The greenhouse effect isolates on the cooling aspect of this flow of energy, it does not create additional energy but rather slows down the outward flow on energy and thus the cooling tendency. A surface that cools more slowly will end up being a warmer surface.
127143. Ned at 23:00 PM on 16 October 2009
        Empirical evidence that humans are causing global warming
        RSVP writes: "In general, what I have noticed in all posts is that no one is able to think for themselves. The validity of any assertion must be backed by an article, google, etc." The problem is that almost every sentence you post here is wrong. It's abundantly clear that you just don't understand even the most basic science involved. People are thus posting links to answers or explanations because they hope you will read them and learn something. It's not a blind appeal to authority by people who are "unable to think for themselves". It's an effort to help you learn something by people who are disinclined to explain the same utterly basic things over and over again when there are handy and informative explanations already written.
127144. RSVP at 21:04 PM on 16 October 2009
        Empirical evidence that humans are causing global warming
        WeatherRusty I used the word "trapped" as does the article. Thumb Heating and cooling mechanisms have nothing to do with whether something is subjectively perceive as being "hot" or "cold". Your CPU's heatsink might feel hot while it is actually cooling your CPU. On the other hand, a thing may be "cooling" or "heating" if the temperature is dropping or raising, but that is a different idea. Riccardo It is not clear where the line needs to be drawn for a website tuned to "Examining the science of global warming skepticism". If something is "wrong" or "trivial", please be more specific. ------------------------------------------------- In general, what I have noticed in all posts is that no one is able to think for themselves. The validity of any assertion must be backed by an article, google, etc. I remember this mentality from the schoolyard (i.e., if I didnt see it on TV, it cant be real, etc.) And more accutely is the sense that anything that appears to stray from "the consensus" is labeled as "political". Ironically, if there was perfect consensus there would be no need for further discussion, however as there is no consenus in reality, the entire discussion is nothing but political, and as such hypocritical.
127145. folke_kelm at 17:22 PM on 16 October 2009
        Comparing CO2 emissions to CO2 levels
        @Alexandre E.G Beck is a retired teacher for biology in germany. His graph makes the big mistake to compare continuous mesurements of well mixed atmosphere with historical discontinuous analysis of air in certain environments. It is obvious, that these historical data are strongly biased by environmental factors. They are taken in urban milieu which is known for higher CO2 levels. If you make some analysis of the air in any lab you will never get co2 levels as low as Mauna Loa levels. In certain cities like Paris, Berlin, London you might get levels above 1000 ppmv.
127146. Thumb at 14:33 PM on 16 October 2009
        Empirical evidence that humans are causing global warming
        "Whatever energy is radiated into the atmosphere by the surface of the Earth, whether by sea or land, represents a LOSS of energy from the surface. There is no radiative heating of CO2 without cooling of the Earth's surface." I suppose this could make sense if there was no sun adding to the mix, but otherwise this sounds like me saying my stove top surface actually cools because it's loosing energy as it radiates heat.
127147. GFW at 11:06 AM on 16 October 2009
        CO2 effect is saturated
        I suppose it's also possible that the satellites were in more-or-less low equatorial orbits, were thus only measuring the tropics, and the tropics have seen the least surface warming. Ok, I'm out of ideas for the moment.
127148. GFW at 11:02 AM on 16 October 2009
        CO2 effect is saturated
        My apologies for what is in effect a repost, but I asked this question at the bottom of a second page of comments where I first saw this diagram. Here I can be first :-) (and I think it's a relatively important question) There is one thing that bothers me about figure 1 (the differential spectrum). The decreased emission in certain absorption bands makes perfect sense. But it's a fact of the (surface) instrumental record that the planet was (a little) warmer in 1996 than in 1970 (somewhere in the 0.1 to 0.2C range). So shouldn't the flat parts of the differential spectrum be just a bit above zero? I suppose it's possible due to different instruments (i.e. different satellites) that they had to normalize, but it would have been so much better if they didn't. Does anyone have the answer?
127149. NewYorkJ at 10:55 AM on 16 October 2009
        Empirical evidence that humans are causing global warming
        Good post. Skeptics might counter with "ok, so humans cause some global warming, but not very much". A next logical progression is to discuss climate feedbacks and why the net feedback is almost certainly positive.
        Response: Funny you should mention that, the next post on climate sensitivity is on that very subject.
127150. GFW at 10:44 AM on 16 October 2009
        How do we know CO2 is causing warming?
        There is one thing that bothers me about figure 1 (the differential spectrum). The decreased emission in certain absorption bands makes perfect sense. But it's a fact of the (surface) instrumental record that the planet was (a little) warmer in 1996 than in 1970 (somewhere in the 0.1 to 0.2C range). So shouldn't the flat parts of the differential spectrum be just a bit above zero?

Prev  2535  2536  2537  2538  2539  2540  2541  2542  2543  2544  2545  2546  2547  2548  2549  2550  Next