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kdkd at 11:38 AM on 23 April 2010Tracking the energy from global warming
I'm still not sure that I understand this TOA/OHC stuff properly. So here's what I've done to BP's spreadsheet though: First to get OHC and TOA in the same units, I standardise them so that the mean is 1 and the standard deviation is 1. Now I run a linear regression model which comes out as: std(OHC) = 0.5 X std(TOA) + 1.4 E10-16 So for every unit that OHC increases, TOA decreases by 0.5. The adjusted R squared for this regression model is 0.22 indicating that TOA predicts 22% of the variance of OHC. The F statistic for the regression is 11.8 (df=1,37) indicating that the regression predicts better than chance. Next I move over to correlation because for a single variable correlation, it's equivalent, and slightly easier to understand. So the correlation between the two variables is -0.49 (p < 0.01) which is strong enough to convince me that autocorrelation isn't an especially big problem, although I lack the knowledge to examine that formally. The 95% confidence interval of the corelation is between -0.70 and -0.21. So what I want to do next is compare the performance of this regression against the UAH satellite data for tropospheric temperature anomaly. Again using standardised data for the 29 years data I have for the satellite record, the formula for predicting standardised temp anomaly from standardised atmospheric co2 is: std(temp) = 0.62 * co2 + 0.3E16 F(df=1,27) = 16.79, p < 0.001 Adjusted R squared is 0.36 The correlations are: 0.62 (95%CI = 0.32 - 0.80) So with 30 data points we're getting a similarly good prediction of some measures of the response to some climate variables to the OHC/TOA data. Now I don't have quarterly data easily to hand for the sattelite data or co2 levels, but I can just look at the final 10 years in the series to see how good that is. However for the data that I have to hand, with only 10 observations, the statistical power is so poor that the regression and correlation is not statistically significant. My conclusion is that the TOA/OHC data that BP presented is what we would expect for a moderately sensitive system with only a small number of data points - and thus limited statistical power. I don't think there's enough data to be able to draw conclusions about the relationship between OHC and TOA to global warming until quite a lot more data comes in. Meanwhile we need to rely on the temperature data, and the associated measures (e.g. ecosystem sensitivity etc) in order to use scientific data to formulate policy. -
HumanityRules at 10:45 AM on 23 April 2010Tracking the energy from global warming
67.Berényi Péter The OHC variablity looks seasonal. Have you tried averaging over a year? "On the other hand, net TOA flux should be very close to proportional to the time derivative of OHC, because there is no other heat reservoir in the climate system with comparable storage capacity." I started to think about the ability of the ocean to release energy. It's easy to imagine that at different times the rate at which energy is lost from the ocean varies allowing build up or loss of energy on a short time period which doesn't always match the incoming energy. -
Chemware at 09:53 AM on 23 April 2010The significance of past climate change
#55 Barry: very nice analysis and data, but it only covers the last 150 years. So the temperature is not in equilibrium as [CO2] is rapidly changing, and the whole climate system is far from equilibrium. That is, if we stopped emitting CO2 right now, the temperature would continue to climb for several decades-centuries. I was after the long-term, equilibrium temperatures, which I think are best obtained from paleo data, because the [CO2] is changing very slowly, and the climate is close to equilibrium. #57 Barry: Yes, this is the Vostok data, which I simply re-graphed to plot Temperature as a function of [CO2], over the last 100 kYears. #67 Chris: Yes, the same old Vostock data, combined (in Fig 1A) with Red Sea sea level data. But simple-minded experimentalist me has just taken the next step and said that if Temperature and Sea Level correlate with [CO2] (as Hansen's graphs clearly show), then let's just plot them against [CO2]. This is shown below. Re-plot of Vostok Ice Core data
Plot of Bard's sea level data against Vostock CO2 data
These are the sort of graphs that Engineers love: if [CO2] is X ppm, then I need to design for a Temperature of Y C, and a Sea Level of Z m.
While one must always be extremely careful with extrapolation, the goodness of fit and the slope of both graphs is very worrying.
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johnd at 08:26 AM on 23 April 2010Flowers blooming earlier now than any time in last 250 years
Given the First Flowering graph was based on UK data I wanted to relate the days of the year to how the seasons progress here in south eastern Australia. Here the autumn equinox happens on day 80, winter solstice on day 172, spring equinox on day 266, and summer solstice on day 356. In the northern hemisphere it follows that spring equinox happens on day 80, summer solstice on day 172, autumn equinox on day 266, and winter solstice on day 356. That means that day 140 on the first flowering index falls a full 60 days after AFTER the spring equinox and just 32 days before the summer solstice. That is certainly different to what we are used to on this opposite side of the world with the first flowering expected weeks BEFORE the Spring equinox. It would seem then that conditions that are global such as the solstices and equinoxes are less relevant than perhaps local conditions. Perhaps it comes down to the plants themselves, or the composition of the species, more spring flowering plants and less summer flowering. I realise it is the relative change that the article focuses on, but given the obvious differences between different parts of the world, it seems to be stretching credibility quite a bit to assume it represents what is occurring globally. -
scaddenp at 07:04 AM on 23 April 2010Skeptical Science Housekeeping: flags, printable versions, icons and links... lots of links
John, I might be missing the obvious but how do you find these links from the main page? Its not obvious to me. I would have expected this under Links (Resources) page, but no go. Is this just failing eyesight?Response: The navigation system needs a serious overhaul - hopefully the next housekeeping effort will include a bunch of navigation dropdowns drilling directly to all these hidden nooks and crannies. -
scaddenp at 06:45 AM on 23 April 2010Greenland's ice mass loss has spread to the northwest
Acushla - I think you are being suckered by misinformation. There are good historical documents for the Greenland colony - confined to 2 southern fiords and plenty of archeological evidence about the settlement too. The ice sheet was firmly in place then, as now. There is no possible doubt about this. -
Jim Eager at 03:39 AM on 23 April 2010Skeptical Science Housekeeping: flags, printable versions, icons and links... lots of links
VoxRat, you have to set the three search parameters at the top your self. -
tobyjoyce at 03:32 AM on 23 April 2010Skeptical Science Housekeeping: flags, printable versions, icons and links... lots of links
I notice that of the 18 "skeptic" articles or media stories from the last month, over half (10) are from Fox News(3), Daily Telegraph(3), Daily Mail(2) and the Washington Times(2). These organisations have a well-known political tilt. Two other organisations share that tilt, the Wall Street Journal and the Australian, which published 1 "sceptic" story each. Now, can anyone tell me if these were balanced with "positive" stories about climate science? I thought so. -
CBDunkerson at 02:36 AM on 23 April 2010Skeptical Science Housekeeping: flags, printable versions, icons and links... lots of links
Looking forward to the Android app. The peer reviewed feature is great, though I notice that the classification isn't 100%. For instance, one of the 'peer reviewed pro-AGW' items is a BBC blogger sounding off about how the 'evils of Climategate' are being whitewashed. On the flags, I'd suggest translating the tooltips into the relevant languages. "View skeptic arguments in Portugese" isn't much help to someone who doesn't speak English and might not recognize the flag of Portugal, but speaks the language... like say, most of Brazil. -
cloneof at 01:44 AM on 23 April 2010Models are unreliable
Riccardo Alright, thank you Riccardo. That totally cleared the things for me. -
Philippe Chantreau at 01:29 AM on 23 April 2010The significance of past climate change
Ther has not been a D.O. event for over 20000 years. Of all the known Bond events, only a small fraction had the potential to affect climate. They seem to lead to an opposite change in the other hemisphere, a phenomenon that has been dubbed the "bipolar see-saw." All in all, the resemblance with what's happening now is so poor as to be irrelevant. All that has already been discussed and referenced on this site before. -
barry1487 at 00:33 AM on 23 April 2010The significance of past climate change
I'm not clever enough to spot that kind of game unless I know the participants well enough. It occurred to me that Tom was being facetious. But it's better to assume straightforwardness if you're not sure when chatting amongst unfamiliars. Wasn't going to comment about that, but seeing as you mentioned it Chris... On another note, I find the reactiveness to skeptics a bit disappointing at times. Don't get me wrong, I've been as frustrated as hell quite often and been pretty abrupt, but I've lately seen well-meaning questioners mobbed with vitriol. I also hope that erstwhile obstinate interlocutors in these climate debates might eventually modify their approach, if not their doubts, if the door remains open. I ask myself "what's my purpose here" and try to operate as if the answer is meaningful. And I'm basically sick to death of the Punch and Judy. Seems to me it achieves the opposite of what is wanted (unless slap-downs are a turn-on for you). That's Nana's lecture for the year. Now back to our feature presentation. -
Riccardo at 00:17 AM on 23 April 2010Models are unreliable
cloneof, the video is a sort of short version of the paper. He calculated a possible cause of error in empirical sensitivity estimates based on random variability of some internal forcing factor. Tuning the variability with just satellite tropical data he found a lower climate sensitivity than the global sensitivities obtained by various GCMs. This is all it has to do with models, Spencer compares his sort of "tropical sensitivity" with GCMs. While the effect of random variability on short term empirical estimates of the sensitivity might in principle make sense, it does not make any sense when he compares his tropical sensitivity with GCMs. This paper is on the very same track of the more recent (and wrong) Lindzen and Choi 2009 paper, similar wrong reasoning that they sell as the definitive proof. -
Chris G at 00:00 AM on 23 April 2010The significance of past climate change
Tom, I meant no disrespect to BC, and I firmly believe that he gives an honest opinion. Above, I had presented the argument that there is a tendency in engineers, when you present information that only makes sense if something they have been assuming is a constant, is in fact a variable, they don't believe what you are telling them. BC, describing himself as an engineer, reported that he balked upon reading something that only made sense if the solar output was not constant, and then came to the incorrect conclusion that John was talking about changes related to earth's attitude or position. That follows very closely with the example I gave above. -
barry1487 at 23:59 PM on 22 April 2010The significance of past climate change
@Berényi Péter at 22:56 PM on 22 April, 2010Abrupt changes have been especially large when atmospheric carbon-dioxide concentration, insolation, and other important climatic variables were changing rapidly, with possible implications for general behavior of the climate system.
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VoxRat at 23:58 PM on 22 April 2010Skeptical Science Housekeeping: flags, printable versions, icons and links... lots of links
"So this allows you to check out all the skeptic peer-reviewed papers published in the last month. Or if you want to keep up with current views, check out the skeptic articles published in mainstream media over the last week." Both the links are to the same (mainstream media) list.Response: Oops, fixed, thanks! -
shdwsnlite at 23:42 PM on 22 April 2010Skeptical Science Housekeeping: flags, printable versions, icons and links... lots of links
Wow! I thought this site was pretty good when I first came across it. Now I am pretty much blown away by how much detail and depth of resources are here. Thank you again John for putting this all together, and thanks to those who help with the features of the site and to all those who contribute to the discussions. It has given me a much better understanding of just what is happening. Though some of the discussions are way out of my league I appreciate the effort to make this site comprehensible to all knowledge levels. -
Berényi Péter at 23:42 PM on 22 April 2010Tracking the energy from global warming
#65 Ken Lambert at 23:04 PM on 22 April, 2010 Can you explain Of course I can. However, I think I have already explained it, just give it some thought on top of reading sentences. The two TOA curves are essentially the same. The difference is a linear trend with a slope. The reason behind it is that TOA fluxes as measured by satellites (recently CERES mission) have large sytematic errors but reasonable interannual precision. At least as long as instrumentation does not change much and intercalibration issues are resolved. On the other hand, net TOA flux should be very close to proportional to the time derivative of OHC, because there is no other heat reservoir in the climate system with comparable storage capacity. Rapid large scale (back & forth) heat exchange between the upper 700 m of oceans and the abyss has no know mechanism, turnover time being several millenia. If climate system heat content is calculated from net TOA fluxes, only the second derivative is measured by CERES with reasonable accuracy, therefore heat content history has a free additive linear term. With OHC, on the other hand, the temporal inegral itself is measured. What I did was to choose the free term for best fit. It can be done for the last six years, but not before first half of 2003. This is the same period when ARGO float deployment was still at an early stage with poor global coverage and rather few floats compared to the target of 3000. At the same time older systems were already phased out almost completely. -
cloneof at 23:29 PM on 22 April 2010Models are unreliable
Riccardo I was going to write about the paper, but I actually found a good video where Spencer explains hi's paper. And at least he gives the impression that it is supposed to do something about climate models. http://www.youtube.com/watch?v=LpFk0zTW-ik -
Ken Lambert at 23:22 PM on 22 April 2010Tracking the energy from global warming
BP #60, #62, #64 I forgot to add - the NODC OHC data in your charts is only the top 700m of the oceans, Yes? If so, the hot topic is what is happening in Dr Trenberth's deeper oceans down to 2000m and beyond. With an average ocean depth of 3700m - there seems plenty of un-explored depth for more 'hidden heat' or is it 'hidden cold'. -
thpritch at 23:20 PM on 22 April 2010Skeptical Science Housekeeping: flags, printable versions, icons and links... lots of links
I am assuming that the paper you are referring to was listed as a "skeptics paper" because it is one that could be used by the deniers given their tendency to re-interpret peer reviewed research to fit their preconceived notions. In the case of the above referenced paper, the deniers could reinterpret the findings along the lines - "because this paper shows that CO2 warming can not account for a significant amount of the observed warming, the models must be wrong and none of the warming is caused by increased CO2 levels." -
Tom Dayton at 23:17 PM on 22 April 2010The significance of past climate change
Chris G and barry, I believe you misunderstood BC's intent. He was helping John by giving his knee-jerk reactions, to simulate an audience's immediate reactions upon seeing the slide presentation, to help John revise his slides to keep that audience engaged and on track. -
Chris G at 23:14 PM on 22 April 2010The significance of past climate change
Chemware, Barry, I believe Hansen et al cover this topic to some extent in "Target Atmospheric CO2: Where Should Humanity Aim?" http://arxiv.org/ftp/arxiv/papers/0804/0804.1126.pdf -
barry1487 at 23:13 PM on 22 April 2010The significance of past climate change
When the sun gets brighter - I baulked at this as my immediate reaction was that you are saying that the sun is emitting more energy. (With thought, I accept that your statement is correct because the sun gets brighter from our perspective because it's closer or the earth is differently tilted due to the Milankovic cycles) As I understand it, our sun has been getting hotter over the aeons. It's not a cyclical process.Even during its current life in the main sequence, the Sun is gradually becoming more luminous (about 10% every 1 billion years), and its surface temperature is slowly rising.
http://en.wikipedia.org/wiki/SunIn the long term, the greatest changes in the Solar System will come from changes in the Sun itself as it ages. As the Sun burns through its supply of hydrogen fuel, it gets hotter and burns the remaining fuel even faster. As a result, the Sun is growing brighter at a rate of ten percent every 1.1 billion years.
http://en.wikipedia.org/wiki/Formation_and_evolution_of_the_Solar_SystemThe continuous fusion of hydrogen into helium will cause a build-up of helium in the core. The rate at which this process occurs depends on the initial mass of the star and ranges from millions to billions of years. Larger, hotter stars produce helium more rapidly than smaller, cooler ones. The accumulation of helium in the core causes a gradual increase in the rate of fusion and gravitational self-compression, as helium is denser than hydrogen. Higher temperatures must be attained to resist this increase in gravitational compression and to maintain a steady state. Eventually, the core exhausts its supply of hydrogen, and without the outward pressure generated by the fusion of hydrogen to counteract the force of gravity, it contracts until either electron degeneracy becomes sufficient to oppose gravity or the core becomes hot enough (around 100 megakelvins) for helium fusion to begin. Which of these happens first depends upon the star's mass.
http://en.wikipedia.org/wiki/Stellar_evolution -
Chris G at 23:07 PM on 22 April 2010The significance of past climate change
BC #63, The energy emitted by the sun is not constant. There are, and have been over the ages, real differences in its energy output that have nothing to do with any orientation or orbital phase of the earth. Sorry, but I'm going to use you as a case in point that engineers often expect things to be constant that are not. -
Ken Lambert at 23:04 PM on 22 April 2010Tracking the energy from global warming
BP #60, #62, #64 Can you explain why the 2003-2009 TOA line from your Post #60 chart does not match the TOA line for the same period from the Post #62 Chart. The values on the energy axes (E22 Joules)are vastly different and so is the shape of the TOA curve, The OHC curve seem roughly the same for both charts. -
Berényi Péter at 22:56 PM on 22 April 2010The significance of past climate change
#21 chris at 00:05 AM on 22 April, 2010 they [Dansgaard-Oeschger events] are not representative of global warming/cooling events Think again. PNAS online Ice-core evidence of abrupt climate changes Richard B. Alley "Ice-core records show that climate changes in the past have been large, rapid, and synchronous over broad areas extending into low latitudes, with less variability over historical times." It is not "global warming" anyway, it is "climate change". And D-O events brought hell of an abrupt climate change for sure. With such an instability, current agriculture would be impossible, billions would perish of mass starvation. Even if such events can not happen in the present warm regime, it is well known at least 7 years worth of food storage is needed. Still, world economy is run on a "just on time" philosophy with less than a year food backup. Grim. -
The significance of past climate change
As an engineer I thought it behoved me to read and comment, so here goes. . When the sun gets brighter - I baulked at this as my immediate reaction was that you are saying that the sun is emitting more energy. (With thought, I accept that your statement is correct because the sun gets brighter from our perspective because it's closer or the earth is differently tilted due to the Milankovic cycles). When volcanoes erupt - my immediate reaction was we've had recent cases (Pinatubo, Krakatoa) where volcanoes have erupted and only caused very short term climate change. (I'm just giving you my first reaction here) So I was in a doubtful mood when I came to the second last paragraph. . the second last paragraph seems to be the key and I didn't find it convincing (Ie on a quick read. Similar to hearing it as part of a talk). It gave me the impression that there are a jumble of variables here and how would you know what's causing what and which variables are feedback. (Again with contemplation I start to realise what you are saying and how it does make sense. By the way, how can ice cores tell us temperature change and solar activity?) PS. I am not a skeptic on climate science. I live in a hot bed of activism on climate change and my daughter tells me you are giving a talk at UQ next month. I'll try and make it. PPS. I read a great comment in an IPCC article or related document about the greenhouse effect and saturation and the build up of pressure due to extra CO2 and the temperature of Venus being 400+ due to it being 98% CO2. I can't find it right now but I'd be really interested in your take on this topic as I didn't understand the build up of pressure bit and how it affects termperature. -
chris at 22:38 PM on 22 April 2010The significance of past climate change
Arkadiusz Semczyszak at 21:50 PM on 22 April, 2010 1. You are misrepresenting Lonnie Thompson's PNAS article, which shows that current warming is likely unprecedented in the areas studied for 5000 year. Since this is an open access article, anyone wishing to know understand this can read it here Note that this work is about mountain glaciers in S. America (Peru); the analyses presented are interpreted in line with similar data from mountain glacier cores elsewhere in the world. 2. You're misrepresenting the science on the LIA. It certainly wasn't "a rapid and permanent change of temperature in about a few years of at least circa 0.8 deg C". One can assess this by inspection of published data also in open access articles. See here, for example (Fig 3). On can only get "at least circa 0.8 deg C" if one goes from the "height" of the MWP to the "depths" of the LIA, and that took around 500 years (not "in about a few years"!). If one takes the more generally accepted temperature decrease to LIA (from around 1200-1600 AD), the temperature decrease was in the range 0.3-0.5 deg C. However one looks at this your interpretation is grossly incorrect. 3. Bond events. There's not much evidence that these are truly manifest within the Holocene. In any case since the last N. hemisphere warmish period was around 1000-1100 AD and the Bond events have a supposed 1500 year periodicity, we shouldn't actually be having a Bond event now at all. In any case you'll need to provide us with some evidence for Holocene Bond events. It's simply not possible to "explain the very existence of the current changes in temperature", without massiverly enhanced anthropogenic greenhouse gas levels. Making stuff up isn't going to aid our understanding! -
Marcus at 22:35 PM on 22 April 2010The significance of past climate change
Arkadiusz, another point. The little ice age didn't occur quickly. Reconstructions show a 0.8 degree fall in temperature over a period of around 600 years-a rate of -0.013 degrees per decade! By contrast, global warming since the 1970's has been at a rate of +0.16 degrees per decade-ten times faster! Also, the LIA is directly connected to both the Maunder & Dalton minimums-coupled with some volcanic activity, wheras recent warming has no solar connection. -
Marcus at 22:30 PM on 22 April 2010The significance of past climate change
Arkadiusz Semczyszak-1st Bond events really would only explain climate change in the Northern Hemisphere. 2nd, almost *every* Bond Event in the Holocene has resulted in *cooling* of the Northern Hemisphere, not warming (like the Iron Age Cold Epoch of 900BC-300BC or the 4.2 KYr event thought responsible for the collapse of the Egyptian Old Kingdom). 3rd, these cooling events have been relatively slow compared to recent warming. So one wonders how you think GLOBAL WARMING is in anyway consistent with Bond Events, when past Bond events-like the 30-year decline in solar activity-suggest that we should be moving into a modest global *cooling* event, if anything-not warming. The fact remains that the only thing consistent with the rapid rise in temperature the last 30-50 years is the equally large rise in CO2 & methane during that same time period. -
Marcus at 22:21 PM on 22 April 2010The significance of past climate change
John, according to my reading, pre-Quaternary global temperatures were frequently around 22 degrees C, around 6-8 degrees warmer than at any other point since. The only exception was a very brief period at the end of the Ordovician Era and again at the end of the Carboniferous Era-where temperatures fell to those closer to modern averages. Both climate change events were preceded by significant drops in atmospheric CO2 (from 7,000ppm to 4,000ppm between the Cambrian & Ordovician Eras & from 4,000 down to less than 1,000 over the course of the Devonian & Carboniferous Eras). What's important, though, is that even though the sun was around 10% cooler than the modern era, the planet's temperature was significantly warmer than today-& the only real explanation is the very high levels of CO2 in the atmosphere-CO2 that we're now re-releasing back into our atmosphere. Yet still some people would have us believe that this massive release can have *no* impact on our global climate. -
MarkR at 22:18 PM on 22 April 2010Skeptical Science Housekeeping: flags, printable versions, icons and links... lots of links
The 'skeptical papers' bit is a little weird. 'Is the basin-wide warming in the North Atlantic Ocean related to atmospheric carbon dioxide and global warming?' is hardly 'skeptical', unless you think that 'skeptical' means 'doesn't think EVERYTHING is CO2 related'! They conclude that CO2 warming contributes ~half of Atlantic warming - I don't see how this makes them a 'skeptical' paper, they're simply adding to a body of evidence on AMO & climate... -
Arkadiusz Semczyszak at 21:50 PM on 22 April 2010The significance of past climate change
"The past geological record indicates that changes on a global scale are invariably very slow. We're talking tens of thousands, to hundreds of thousands and even millions of years in the vast majority of cases." "The fact that virtually *every* natural climate change event in the past (with the exception of those caused by extremely massive natural disasters) has occurred at a rate of between 1/2 to 1/10th [???] of the rate of recent change is simply further proof that nature is not the cause of the most recent climate change event." ... This is a representation of knowledge - science, with a few years. At least. Repeatedly (here) I proposed-presented, a graph: http://www.pnas.org/content/103/28/10536/F4.large.jpg. Why? 1st L. G. Thompson is a definitely not a skeptic. 2nd Certainly his work only for Africa but (as one of the few) dates back to 2003. Please look at the changes in the eighteenth century. It is difficult to explain only the increase in volcanic activity in the LIA. LIA began, moreover, a rapid and permanent change of temperature in about a few years of at least circa 0.8 deg C. Chris - why? After all, there were no significant changes in ice surface ... Certainly the current change is unprecedented, but certainly no more violent than the old change! For example, according to v. Storch once looked like this: http://www.korthweb.de/PhZT/Temperatur_Intcal2.gif Moreover, the current temperature change fits neatly into the sequence of Bond Events (not to be confused with D-O). CO2 is not needed to explain the very existence of the current changes in temperature ... -
Berényi Péter at 20:54 PM on 22 April 2010Tracking the energy from global warming
#63 kdkd at 19:43 PM on 22 April, 2010 Is a csv file of the raw data available anywhere? I could not collect proper data files, so re-digitized both NODC OHC & CERES FLASHFlux (pp. 21) graphs. You can find the csv here. The dimension is 1022 J for both columns, offsets arbitrary, slope of TOA radiation imbalance as well (being the temporal integral of a function with offset unknown). Time resolution is three months. -
kdkd at 19:43 PM on 22 April 2010Tracking the energy from global warming
BP #62 Thanks. What's the cause of the difference between the TOA line in the first graph compared to the second graph? Is a csv file of the raw data available anywhere? I wouldn't mind doing some crude resampling stats on the time series. -
Jacob Bock Axelsen at 18:40 PM on 22 April 2010Are we too stupid?
gallopingcamel We are in the middle of the holocene extinction event due to the lack of intelligent self-interest. The policy of laissez-faire is so appealing, and control so disgusting, that it is only now we might realize that we need control. Instead of putting trust into the "invisible hand" then let us intelligently devise a real visible hand to point the direction of best self-interest. Indirect reciprocity will take care of Joe and his friends as they are not islands entire of themselves. I have never heard of non-perishable foods. That seems to me to be the actual reason for inventing money. Natural trees are not good sequesters with respect to excess CO2 in the atmosphere. Even the Freeman Dyson knows that. A "year without a summer" would be an emergency independently of any plan to mitigate global warming. The prospect of disaster is still not a good justification for creating mountains of rotting food for no use most of the time. I am in favor of a new clean generation of nuclear power, but that may take long and they are very expensive to build. Geothermal is a low-hanging fruit in comparison. I hope this was useful to you. -
barry1487 at 18:12 PM on 22 April 2010The significance of past climate change
There's the ice age CO2/temp graph at wiki, too, a bit down the page on the right, though it's only a straightforward comparison. http://en.wikipedia.org/wiki/Ice_age#Origin_of_ice_age_theory -
Glenn Tamblyn at 18:10 PM on 22 April 2010The significance of past climate change
John If you are talking to Engineers, admitedly a very specific audience, try following the energy trail. Radiation Budget, Joules of heat in the ocean etc. Get them onside by doing the 'laymen may focus on temps but we know its about the energy trail'. -
barry1487 at 17:53 PM on 22 April 2010The significance of past climate change
Chemware - is this the kind of thing you're looking for? http://residualanalysis.blogspot.com/2008/06/anthropogenic-global-warming-is.html http://residualanalysis.blogspot.com/2009/12/statistical-proof-of-anthropogenic.html http://moregrumbinescience.blogspot.com/2009/03/does-co2-correlate-with-temperature.html http://bp3.blogger.com/__6PO0G1BcJM/SHjWm0gCguI/AAAAAAAAACk/BsbMNnwz0Go/s1600-h/figure2b.JPG -
Chemware at 17:01 PM on 22 April 2010The significance of past climate change
#39 Momerath "Being engineers I’m sure at least one asked to see a graph of atmospheric CO2 concentration verses temperature for our planet. Since such a graph does not exist ..." That bugged me too, about a year ago. No amount of googling could find such a graph. So I downloaded the Vostok ice core data, graphed it over the last 100 kYears. You can see the results here: http://home.exetel.com.au/chemware/Paleoclimate.htm I also grabbed some sea-level data by Bard et al., and interpolated that to construct a similar graph for sea levels. Both plots are remarkably linear. They also have alarmingly large slopes. -
Chris G at 16:56 PM on 22 April 2010The significance of past climate change
I have a pet hypothesis that is in the same vein as Barry's. Another, layman speculation here; so, keep that in mind. I somewhat think that there are plateaus in global temperatures, and the within a plateau, a certain amount of change in forcings has less effect that near the edge of one. I'm imagining a few mechanisms for this, but I'll just try to explain just one. Let's consider the Greenland ice sheet and the albedo of the surface area it occupies. Let's say there is an ice sheet, and the mean temperature over it is -6 C. (Yeah, I know it'll be warmer in the south and colder in the north, on average, and the actual degrees are just for illustrating a point. Humor me; I like to keep things simple.) About 90% of the energy received is reflected. Let's say you have a change in some forcing that raises this area's mean temperature by 4 C to -2 C. The ice sheet remains, and the change in climate is more or less linear (or probably a log) of the forcing. Let's say there is some additional forcing that, by itself, would push the mean temp to +2 C, and the ice cap melts. The albedo changes, the temperature raises some additional factor, and whatever relationship between forcing and effect that existed when the temp was between -6 and -2 C is not the same relationship that you will find between -2 and +2(+x). Same effect on the way down, in reverse. So, if it likely to be the case that there is not a consistent relationship between the amount of forcing and the amount of climate change, it is going to be difficult to anticipate where the current change in forcing will take us. Will we stay within this plateau, or will we be leapfrogged to some other? I believe Hansen has written along these lines better than I can. The point is, engineers are used to thinking in terms of coefficients that relate x to y, but they aren't always prepared to deal with coefficients that are not constant. If some engineer isn't prepared to deal with a variable coefficient, and they detect that it wasn't the same in scenario A as it was under scenario B, you'll loose them. When they learn that the coefficient isn't constant, but don't have a grasp of the larger forces in the equation, they can also come to some erroneous conclusions. In my own experience, I remember aerospace students, when they learned that the coefficient of drag of a sphere decreased with an increase in velocity, jumped to the erroneous conclusion that the drag itself reduced. No, the drag (subsonic) is still proportional to the square of the velocity, and the square of the velocity goes up a lot faster than the coefficient goes down. If there are questions about runaway feedbacks, you can always point out that the energy radiated by a body is proportional to the fourth power of the absolute temperature, and no other part of the equation has that large an exponent. Engineers will get that. I get the same feeling as I did with the decreased drag arguments when I hear arguments that the negative feedbacks, like increased cloud cover, will prevent warming. a) What, water molecules are going to anticipate a warming and leap up to form clouds to prevent it? No, they evaporate more than they had been because they are warmer than they had been. It's not like they weren't evaporating and forming clouds before at some equilibrium level. Clouds might mitigate a warming, but they can not prevent it. Nevermind that water vapor is itself a GHG. b) The changes in the past are a strong counterpoint to the idea that the climate is inherently stabilized by negative feedback mechanisms. Maybe that is my second point. It may be too much of a stretch to jump in saying that changes in the past support that we are changing climate now; it might be better to say that changes in the past establish that a change in forcings can very well change the climate. From there, those that are with you up to that point will naturally start to ask how much forcing are we doing now as compared to some other forcing at some other time. I haven't seen your talk; so, I'll just hazard a guess that some were still eating the first course when you yanked it and presented desert. Well, it's late, I've let myself get long winded, and I'm a choirboy preaching to the preacher. Good night and good luck. -
jibal at 16:48 PM on 22 April 2010Where is global warming going?
suibhne has been peddling the same ad hominem nonsense about people misusing the word "heat" (and therefore they are supposedly wrong about global warming) at http://scienceblogs.com/deltoid/2009/03/gerlich_and_tscheuschner_oh_my.php where he has repeatedly been refuted but has refused to address any of the substantive criticisms. -
Berényi Péter at 16:28 PM on 22 April 2010Tracking the energy from global warming
#61 kdkd at 12:48 PM on 22 April, 2010 Is this possible, or is that data not available? CERES FLASHFlux only goes back to 2000. If I take all ten years and apply the same procedure it looks like this:
The fit is awful because of the huge step-like change of OHC in early 2003 and also the high noise level before. I guess these features are measurement errors due to changing coverage & instrumentation.
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Acushla at 16:13 PM on 22 April 2010Greenland's ice mass loss has spread to the northwest
It has happened to Greenland in the past when ALL the ice melted. The people had a prosperous time for many years and they enjoyed it.Response: There is no recorded history of the last time ALL the Greenland ice melted - the Greenland ice sheet is at least 400,000 to 800,000 years old. -
cloneof at 15:53 PM on 22 April 2010Models are unreliable
Riccardo As I have just a few minutes let me first just apologize for not giving the refrence. It was almost ill responsible to brag about a paper that I didn't even give the refrence to. I will give you an response later today. -
Berényi Péter at 15:41 PM on 22 April 2010Where is global warming going?
#39 chris at 00:18 AM on 22 April, 2010 so what Peter? Have a look and compare coverage. -
barry1487 at 14:22 PM on 22 April 2010The significance of past climate change
So if someone asked about CO2 being much higher in the past (noone did bring that up at the talk), I would say that the sun has been getting steadily brighter over Earth's history. I go a bit further - but as I'm a layman I would like to check with you. I put it that the configuration of the biosphere was also very different, notably a big difference in where land masses are situated. Albedo has a strong influence, so if there is more or less land on our near the poles, this can strongly impact the radiation budget. Directly comparing the biosphere now with that of millions and millions of years ago, in terms of CO2 influence, is a bit of an apples to oranges thing. Is this a fair comment or have I been getting it wrong? Also, would different ocean/atmosphere heat transport dynamics in the distant past have an impact on the total radiation budget, or does it even out for the global total? (Hope that made sense) -
kdkd at 12:48 PM on 22 April 2010Tracking the energy from global warming
BP #60 That's interesting. But I want to see it on a more appropriate time scale. 30 years is a good minimum for looking at climatic effects (rather than weather effects). Is this possible, or is that data not available? -
gallopingcamel at 12:43 PM on 22 April 2010Are we too stupid?
Jacob Bock Axelsen (#106) "Now, enough of what I know. What are your solutions to mitigate climate change?" Two things I could support: 1. Reducing Carbon Emissions As long as this is done via a rapid build up of innovative nuclear power plants (Generation IV) until the cost of electricity is low enough to convince “Joe Six-pack” to trade in his 4X4 for an electric vehicle. No government mandates; just let intelligent self interest persuade the masses. I love my electric car because it is fun to drive rather than its ability to reduce my “Carbon Footprint”! 2. Major Carbon Sequestration Programs Carbon should be sequestered along the lines pioneered by Hammurabi (Babylonian empire). Farmers should be encouraged to overproduce non-perishable foods and timber. The EEC was on the right track with its “Butter Mountains” and “Wine Lakes” although these products were too perishable. Have you ever wondered what would happen to our wonderful high tech civilisation if the recent Icelandic volcano had been a Mount Tambora? How well would we handle another 1816, the “Year without a summer”?
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