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Stephen Baines at 00:17 AM on 13 May 2010Estimating climate sensitivity from 3 million years ago
RSVP It doesn't matter that it is more tangible. Imagine a bar for a waste heat forcing of 0.027 W/m2 on the forcing graph Doug Bostrom shows above. You would have a hard time even distinguishing it from 0. It's just not enough heat to matter much. -
Ned at 00:16 AM on 13 May 2010Earth's five mass extinction events
The back-and-forth between batsvennson and chris in this thread might be a bit confusing for anyone who hasn't followed it closely. Back on the first page of comments, batsvennson wrote: [...] we may postulate a hypothesis that the current increasing of atmospheric CO2 concentration is a consequence of an current ongoing - for some reasons - (mass) extinction. This seems very peculiar to me. We know that we're adding CO2 to the atmosphere from combustion of fossil fuels, land use, and other factors. So the increase in CO2 in the atmosphere isn't a mystery. Batsvensson's hypothesis would necessitate some unknown mechanism removing anthropogenic CO2 from the atmosphere and some other unknown mechanism adding CO2 due to an ongoing mass extinction. (There is plenty of evidence that we are in the midst of a new mass extinction, caused by human impacts on the biosphere, but no evidence that this inherently is causing a large CO2 flux.) Occam's razor suggests that an explanation with zero unknown processes is preferable to one that requires two different unknown processes. So, Chris understandably points out (in this comment) that batsvensson's hypothesis is probably not a productive line of scientific inquiry: As for your "hypothesis"; why would we propose or consider a hypothesis for which there is not only zero evidence, but which is robustly contradicted by what we know of the real world? I don't see how it takes us anywhere scientifically speaking... batsvennson then asks Chris for more elaboration on these objections, and Chris obliges in this comment. There is some subsequent back-and-forth, ending with this very strange statement by batsvennson. Not all hypotheses are created equal. On the subject of the increasing CO2 concentration in the atmosphere, consider the following two hypotheses: H1: The increase is primarily due to combustion of fossil fuels. H2: The increase is primarily due to invisible leprechauns. I think most people would agree that the former is more productive than the latter, not just because it's more realistic but because it's testable. A hypothesis that is stated in vague, ill-defined terms, or that requires unknown and unexplained phenomena, is not really testable and thus is not particularly useful. Here's another case: H1: The increase is primarily due to combustion of fossil fuels. H3: The increase is due to the rapid deterioration of an undiscovered lens of frozen CO2 (dry ice) buried beneath the topsoil of a remote region of the Himalayan plateau. Now, unlike the leprechaun hypothesis, H3 is actually testable -- NSF or its European or Chinese equivalents could fund a field campaign to travel to Tibet and look for this interesting dry-ice feature. However, it's unlikely that a grant proposal focused on this hypothesis would be funded. Why? Because there's no prior evidence or reasoning to suggest that it's even remotely likely. A hypothesis with no justification for its own existence is better than an untestable hypothesis, but not much. Moving on, consider the next two hypotheses: H1: The increase is primarily due to combustion of fossil fuels. H4: The increase is primarily due to outgassing of CO2 from the oceans as they are warmed by a cyclical increase in solar irradiance. Now, H4 is clearly better than the leprechaun or dry-ice hypotheses -- it is testable, and it is at least based on plausible physics and some things we know about the relationship between temperature and the partial pressure of gases in seawater. But it still has problems -- in particular, it conflicts with other things we already know about the Earth system (solar irradiance has been decreasing, CO2 concentration in surface waters is increasing as CO2 moves from the atmosphere to the ocean rather than vice versa). In addition, H4 still requires some unknown explanation for why the CO2 that we know we're emitting from our cars and power plants is somehow not contributing to the atmospheric store of CO2. Now, batsvennson's hypothesis suffers from the problems of H3 and H4 above. She/he doesn't present any evidence to justify why we should even bother to consider "an ongoing mass extinction" as an explanation for the current rise in CO2, aside from one brief reference to a paper that suggests that some mass extinctions in the geologic past may have caused an increase in the CO2 flux from the biosphere to the atmosphere (but where's the evidence that's happening today?) More importantly, however, it is contradicted by the changing isotopic signature of atmospheric carbon. Finally, from a straightforward logical perspective it requires throwing out a much simpler explanation (we know we're producing CO2 from fossil fuels) in favor of a more complex one. As Carl Sagan said, extraordinary claims require extraordinary evidence. The claim that "something other than combustion of fossil fuels is responsible for the current rise in CO2" is most definitely an extraordinary claim. It's up to anyone proposing such a claim to provide extraordinarily convincing evidence. So far, batsvennson has provided no evidence at all. -
RSVP at 23:35 PM on 12 May 2010Estimating climate sensitivity from 3 million years ago
Ned "Likewise, when you add CO2 to the atmosphere, you're essentially creating lots of tiny machines that add X joules every year,.." Well put. I understand the "theory"; however, there is no theory required to quantify waste heat. -
James Wight at 23:14 PM on 12 May 2010Heat stress: setting an upper limit on what we can adapt to
I notice you’ve added this to the list of global warming impacts. I think it might be worth pointing out that some pretty extreme global warming (at least 7°C) is required for this to happen. -
Ned at 23:10 PM on 12 May 2010Estimating climate sensitivity from 3 million years ago
Oh, yes ... I forgot to add this: You write "The fact that [waste heat] is so easily calculated demonstrates how tangible it is." But it's much easier to calculate the heat added to the atmosphere from greenhouse gases than it is to figure out the total of all sources of waste heat! The complexity in predicting radiatively forced climate change is not in the initial heat transfer, it's in all the various feedbacks. -
Ned at 23:04 PM on 12 May 2010Estimating climate sensitivity from 3 million years ago
RSVP writes: Waste heat is perfectly tangible, unlike the indirect and complex effects of anthropogenic greenhouse gases. The fact that it is so easily calculated demonstrates how tangible it is. There's no difference -- heat is heat. Just in one case it starts out concentrated around chimneys, cars, etc. before dispersing, while in the other it's horizontally dispersed throughout the atmosphere right from the start. But the heat created by radiative transfer is every bit as real as the heat created by any other mechanism. If you insist on comparing CO2 to waste heat, you should think of the CO2 as equivalent to the machines that produce the waste heat, not the heat itself. If you add X joules of heat to the atmosphere, you increase the heat content of the atmosphere by X joules full stop. If you build a machine that adds X joules of heat to the atmosphere per year, then you've added X*L joules, where L is the lifespan of the machine in years. Likewise, when you add CO2 to the atmosphere, you're essentially creating lots of tiny machines that add X joules every year, and that will keep doing so for roughly a century or so. And every year we create more of these machines ... -
embb at 22:24 PM on 12 May 2010Are we too stupid?
Jacob:What gives you the idea that reducing CO2 emissions makes a country's industry uncompetitive? Aren't we talking about an emission tax? It will increase the production costs hence make the industry less competitive. Jacob:OPEC is an excellent example of how powerful a coalition using reciprocity can be. If you think so... I seem to remeber lots of defections during its existence. Also, Russia, one of the biggest producers, is not a member. Are you sure this is the right model? Jacob:Neither I nor the EPA ever postulated that. Whatever gave you that idea? Simple: CO2 is a pollutant. People prefer to live in less polluted areas. Thus people should be willing to pay for having less CO2 in their area. Some element of this chain is faulty, which one is it? Jacob: You just dismiss that "The Lancet and University College London's Institute for Global Health issued a major report concluding that climate change is the "biggest global health threat of the 21st century."? No, I did not. You were talking about "immediate" effects, they are ttalking about "threats". Surely you see the difference. Jacob:Do you think geo-engineering is more or less risky than switching to sustainable energy? You completely miss my point. You were advocating immediate actions regardless of the risks. I am asking YOU if this is your attitude towards geo-engineering as well? Remeber? "So you argue for the preservation of the status quo because the proposed reforms may be imperfect? That is why I conclude that you have an interest in not mitigating climate change." If you argue against geo-engineering then according to YOUR own logic you have an interest in not mitigating climate change. That is all. Jacob:There is no police force in the case of the fig tree/fig wasp, is there? You might want to rethink this a bit. Evolution is about the survival of the fittest - so defectors will just die. If this is your example of a non-violent scenario you are really wrong. :) -
Zero132132 at 22:23 PM on 12 May 2010Heat stress: setting an upper limit on what we can adapt to
I haven't had time to look into it yet, so I must ask, does this study include the effects of increased temperatures on the amount of water vapor in the air? It would seem that both an increase in water vapor would drive the wet-bulb temperature, unless I'm misremembering something from genchem. -
RSVP at 22:13 PM on 12 May 2010Estimating climate sensitivity from 3 million years ago
chris Waste heat is perfectly tangible, unlike the indirect and complex effects of anthropogenic greenhouse gases. The fact that it is so easily calculated demonstrates how tangible it is. Waste heat goes directly into oceans and rivers (and the air) everyday, 24 hours a day. Power plants are water cooled for the most part, and the atmosphere does not get a chance to see this heat until it is exchanged at sea. Waste heat is real and accumulating, and yet somehow considered an inconvenient piece of data that is best ignored. I am not denying effects of GHGs, but it would be a useful exercise to assume a zero contribution of anthropogenic GHG (for the exercise) just to estimate how this alone would affect temperatures (assuming it is accumulating in some percentage). And in comparing to the actual average global temperature increase, this would help determine how much is actually due to anthropogenic GHGs. KR You comment that the higher the temperature, the more IR. I agree, but this applies to all forms of forcing, and is basically a form of negative feedback which maintains temperature convergence (to the benefit of all). -
Ned at 22:00 PM on 12 May 2010Estimating climate sensitivity from 3 million years ago
I agree with Dikran Marsupial that one can't draw conclusions about climate sensitivity by looking just at CO2 and temperature over the first half of the 20th century, since there were countervailing trends in other forcings. Here's a handy figure from Meehl et al 2004:
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Ned at 21:51 PM on 12 May 2010Heat stress: setting an upper limit on what we can adapt to
Arkadiusz Semczyszak writes: Thesis GW = greater frequency heat - it is already outside the mainstream of science. Not at all -- quite the opposite, in fact. The largest increase in temperatures is in winter and at night, but there's also an obvious trend of increasing intensity of extreme summer heat waves. Just looking at some recent papers, we find: Ballester et al. (2009): "... the increasing intensity of the most damaging summer heat waves over Central Europe is mostly due to higher base summer temperatures ... 36% (B2) to 47% (A2) of future Central Europe July and August days at the end of the present century will be warmer than the 1961/1990 99th percentile." Beniston et al. (2007): "Heat waves – Regional surface warming causes the frequency, intensity and duration of heat waves to increase over Europe [...] The intensity of extreme temperatures increases more rapidly than the intensity of more moderate temperatures over the continental interior due to increases in temperature variability" Meehl and Tebaldi (2004) Clark et al. 2006: " [...] Although uncertainty associated with the magnitude of expected changes is large in places, it does not bring into question the sign or nature of the projected changes. Even with the most conservative simulations, hot extreme events are still expected to substantially increase in intensity, duration, and frequency. [...]" I'm not sure why you think that increasing frequency of heat waves is "outside the mainstream of science" when it's actually one of the most robust findings of both observational and modeling studies. -
CBDunkerson at 21:27 PM on 12 May 2010Estimating climate sensitivity from 3 million years ago
Dikran Marsupial #82, true. Looking only at CO2 oversimplifies the issue considerably. However, if you look at the chart doug provided in #71 you'll see that various other forcings (including solar) are comparatively minor and largely cancel each other out. If all the uncertainty bands came out with the highest possible result for each forcing that would just about equal the observed warming... but that isn't possible because parts of those uncertainty bands are from overlapping sources. For instance, we know that sulfate aerosols have a strong cooling effect, but we aren't sure how much of that is directly from the sulfates and how much is indirectly from compounds they form... so both forcings have large uncertainty bands, but they can't both be the highest (i.e. closest to zero) value. In short, the observed warming can't be explained even when we include all the known forcings... leaving unknown forcings or feedback effects to explain the difference. And we KNOW feedback effects are taking place because we can measure the change in albedo from ice retreat and the increase in water vapor from rising temperatures. -
Arkadiusz Semczyszak at 20:30 PM on 12 May 2010Heat stress: setting an upper limit on what we can adapt to
#14 And even well-known popularizer of knowledge Ron Redfern in his book "Origins" (2000), writes that in the tropics during the last glaciation may have been even more tropical than at present (significant reduction - compression THC) and the Northern Siberia, formed stable - static for thousands of years - Anti-cyclones. Strong warming is perhaps the disappearance of cyclones - almost pressure gradient = 0? In summer, temperatures in Siberia could be as high as above 45 deg C ... Sherwood'a work is very valuable and interesting but not very useful for prediction of ways to adapt to GW. Thesis GW = greater frequency heat - it is already outside the mainstream of science. -
chris at 19:58 PM on 12 May 2010Estimating climate sensitivity from 3 million years ago
RSVP at 18:58 PM on 12 May, 2010 RSVP, doug has already corrected for a spherical Earth, angle of incidence, albedo. The TOA average solar radiation is 1,366 W.m-2. If you divide by 4 to account for a spherical Earth, and multiply by 0.7 - 0.8 to account for the Earth's albedo, the surface solar radiation is around 250 W.m-2 averaged over the Earth's surface. Please stop these tedious attempts to pursue false arguments based on ignorance. You've been here long enough to have learned some basic backround information on these subjects. The idea that a straightforwad subject like the contribution of waste heat to the Earth's energy balance has to be gnawed over by a boring recapitulation of the whole theory and empirical knowledge of radiative forcing and energy balance, as if the subject has only just been awakened and needs to be sorted out fom scratch on this thread is tedious in the extreme. Several useful sources of info on this have been posted aready on this thread - please go and read them... -
RSVP at 18:58 PM on 12 May 2010Estimating climate sensitivity from 3 million years ago
doug_bostrom "surface of the Earth is about 510,000,000 km2. So, about 127,500TW of total insolation" You are taking the total surface area. Only one side of the Earth gets Sun at any given time, so you will need to at least half that result for starters and reduce some more to account for albedo. In any case, the absolute amount of insolation is supposedly a non-issue (neither here nor there) for those that base their analysis on the radiative forcing model (the tree graph that has branches going left and right). Its funny how the total solar insolation is never mentioned in that context, only when the question of waste heat is brought up. -
Riccardo at 17:31 PM on 12 May 2010Estimating climate sensitivity from 3 million years ago
johnd, 2xCO2 correspond to about 3.7 W/m2. Multiply that number by 0.0075 and you'll get the forcing in W/m2 (0.028 W/m2) which is obviously the same you'd get using the formula i gave you before. It's just a simple change of the unit of measure. But again, this is not the main problem with your reasoning. You're still missing that the forcing due to increased absorption need to be summed up over time, waste heat does not. -
Bern at 17:11 PM on 12 May 2010Heat stress: setting an upper limit on what we can adapt to
Further to my last post - I wasn't able to dig up the extremes, but Darwin has a reputation for pretty unbearable weather in summer. Going by BoM data, the mean 3pm wet bulb temperature in January is 26.4ºC. -
Dikran Marsupial at 17:03 PM on 12 May 2010Estimating climate sensitivity from 3 million years ago
CBDunkerson wrote: "Using the actual CO2 figures for today vs 100 years ago gives ln(387/300)=0.367371 C warming... as opposed to the ~0.7 C actually observed. Ergo, we have observed more warming than can be explained by the enhanced CO2 greenhouse effect. Thus demonstrating that total feedback effects over the past hundred years have been positive." Wouldn't that be the case only if anthropogenic CO2 were the only change in forcing? IIRC the IPCC report attributes most of the warming of the first half of the 20th century to changes in solar forcing. So the difference between the 0.7C and 0.36C could simply be due to changes in other forcing, rather than being the consequence of feedback. Don't get me wrong, I am confident in the ability of the climatologists, and the bulk of the evidence gives little support to low sensitivity, although I keep an open mind on it - and await Roy Spencers new paper. -
Bern at 16:55 PM on 12 May 2010Heat stress: setting an upper limit on what we can adapt to
@Joe Blog: yes, there are calculations, but the easier way is to look up a psychrometric chart. They can be a bit hard to read, though. Wikipedia has some here. You can tell from looking at the charts that the conditions to get to a wet bulb temperature of 35 are pretty extraordinary (something like 75% relative humidity at 40ºC). Remember that relative humidity also drops rapidly with increasing temperature unless you put a lot more water vapour into the air (0.02g H20 per gram of dry air = 100% RH at 25ºC, but only ~34% RH at 45ºC). There's some more info about apparent & wet bulb temperatures (including formulae) on this Bureau of Meteorology page. -
Joe Blog at 14:41 PM on 12 May 2010Heat stress: setting an upper limit on what we can adapt to
Ive also spent a bit o time in the jungles in the tropics... A decade or so ago, i spent six months kicking around East Timor... And three months of that at Suai, which is basically a big valley/swamp, and even though its further south than Dilli (the capital) Suai is generally approximately 10C warmer(generally fluctuates between lows of 35C and 45C. With extreme humidity(90%+) I dont know how this compares with the wet bulb taken into account? Ive seen a fair few people drop with heat stroke(hypothermia???) And some people dont handle it well at all.(might last 10mins o a two week patrol, but this is with 60 odd kgs on yer back.) But just too me, it seems 35 is a tad on the low side As far as survivability goes... Is there a calculation showing what temp C vrs humidity is equal to wet bulb temp? -
thefrogstar at 14:21 PM on 12 May 2010Heat stress: setting an upper limit on what we can adapt to
One of my biggest issues with living in one of those red zones is that the noise of the air conditioning affects my mental health. That and the cockroaches. On the plus side, I'm told that our electricity in South Carolina comes from nuclear power. Think I'll treat myself to another "guilt-free" cold one. Cheers! -
Doug Bostrom at 14:10 PM on 12 May 2010Hockey stick is broken
By a couple of common metrics such as overweening attention paid to what frankly appear as imaginary slights against the author on the part of a host of what he characterizes as conspirators, that "Casper and the Jesus paper" item appears to have been written by a crackpot. Yet the author has been published, patiently refuted and refuted again in a very professional manner by a number of researchers. I'd call that an excellent demonstration of scrupulous inclusiveness of outsiders on the part of the climate research community. -
Doug Bostrom at 13:48 PM on 12 May 2010Estimating climate sensitivity from 3 million years ago
Clouds have -what- to do with the comparison of human-liberated waste heat and C02 forcing? Changing topics, much? -
johnd at 12:03 PM on 12 May 2010Estimating climate sensitivity from 3 million years ago
Stephen Baines at 11:32 AM, perhaps you can explain the difference between 2xCO2/year and W/m2/year. My original read of the link revealed this clarification:- "It is a common convention in the literature to use 2xCO2 as the unit for forcing, rather than W/m2" I double checked and I did read that right. I assume that you also read it as it did not require a particulary close read to come across it. That leaves the possibility that the units cannot be exchanged in this application. Perhaps you can explain why that might be the case. -
Stephen Baines at 11:34 AM on 12 May 2010Estimating climate sensitivity from 3 million years ago
I meant the "increase of a rate"! This is too loopy. -
scaddenp at 11:33 AM on 12 May 2010Hockey stick is broken
John, I would check whether the Holland paper is peer-reviewed even by E&E "standards". poptech - interesting that you fixate on this. (especially in light of Mann 2009 and all the other reconstructions) What do you think it means? Got "demolitions" for all the other proxy papers as well or this is a crusade against Mann? -
Stephen Baines at 11:32 AM on 12 May 2010Estimating climate sensitivity from 3 million years ago
73 johnd I followed your link. You should read more closely. That 0.0075 value is measure of the rate of change of CO2 in the atmosphere relative to a doubling. It does not have W/m2/year units at all but units of 2xCO2/year. The same link suggests calculating the forcing per relative change in CO2 concentration as described in the post you cite as =5.35 ln(C1/C0) - exactly the same as a previous post. The calculation of this on a year by year increment basis makes no sense for comparison with waste heat production rate, as others have stated. One is an increase in the rate of a rate, and the other is just a rate. It's not like we can pretend that CO2 we put up in the past isn't there and isn't doing anything. Why do you discount all the evidence people here were providing rather that go back and checking to see if you read right? -
Ned at 11:31 AM on 12 May 2010Estimating climate sensitivity from 3 million years ago
HumanityRules, as scaddenp notes clouds aren't a forcing. However, there's a very, very well written discussion of forcings and feedbacks -- including clouds -- at Chris Colose's place. Check it out! The very short version of the answer is that uncertainty about clouds is responsible for much of the gap between low vs. high estimates of climate sensitivity (i.e., 2.5 vs 4.5 C). -
Tom Dayton at 11:18 AM on 12 May 2010Climate Change and the Integrity of Science: a letter to Science
Geo Guy, Stephen Baines told you to "Check elsewhere on this site for proof" that CO2 is well mixed. Here are some of those elsewheres: The post CO2 measurements are suspect, including the comments. In particular, click on the links in my comment of 18:10 PM. Also click the links in my comment 13:54 PM, and be sure to then read this comment by dhogaza and this one by cbrock that are in the thread Is the airborne fraction of anthropogenic CO2 emissions increasing?. -
scaddenp at 11:01 AM on 12 May 2010Estimating climate sensitivity from 3 million years ago
HR - clouds are a response/feedback not a forcing. Unless someone can find a way to make clouds independent of temperature and aerosols. If the GCR hypothesis was proved, then that could be a way but so far no go there. -
Stephen Baines at 10:45 AM on 12 May 2010Climate Change and the Integrity of Science: a letter to Science
Geo Guy #219 Whether it’s the US or the world doesn’t matter, nor does it matter whether you got the data from EPA. You’ve got the units wrong. I went to the EPA reports. US CO2 emissions were 7,200 teragrams in 2006. SO2 emissions in the same year are reported to be about 10 million tons (which is 9 teragrams). That’s 762x less SO2 emissions per weight than CO2 emissions. Per atom that ratio rises to 1165x less. Per ionic equivalents its 562x less. Seriously, you really don’t do your case a service by making such simple mistakes and sticking to them though you could easily have corrected them. http://www.epa.gov/airmarkets/progress/ARP_2008_Highlights.pdf http://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=P1000KQ1.txt Volcanic gases are an interesting case that actually proves my point. They do sink because they are NOT mixed with the atmosphere when they come out of the earth, so the plume of gas is heavier because of its high CO2 content. Same thing happened when that killer lake in Cameroon burped CO2, killing all those people in the 80s. But this tendency for CO2 to sink only lasts as long as the plume is coherent. When the plume eventually mixes with the atmosphere due to wind driven turbulence, the CO2 molecules no longer sink. Good thing that happens quickly or we would all be running away from herds of renegade volcanic plumes on the prowl. As for acidity making its way unaltered through lakes and streams, think about the implications of what you are suggesting. Rain is acidic, has been for eons. Sometimes it’s really acidic if a volcano erupts. If it lands on earth and makes its way to the oceans without interacting with rocks through weathering what would the ocean look like? That’s right, it would be acid. It would not have sodium or calcium or magnesium which are all released in weathering reactions involving acids and eventually accumulate in the oceans. There would be much less phosphorus in the ocean to support life. It would have SO4, and Cl and CO2, all acid ions since these come from volcanoes. Not only that but ALL lakes (not just some) would be acidic as well. You would not see the great variety in lake chemistry that you have noted. What you are suggesting doesn’t isn’t consistent from your own perspective. You seem to be someone who likes to appeal to common sense. Scientists really are no different – they want explanations that are consistent with their experiences and those of their colleagues. What you are suggesting above directly contradicts what you and virtually every else knows to be true from personal observation. Only under very special circumstances do we asphyxiate from CO2, and the ocean is salty. Because they are generally familiar with a greater diversity of such observations, scientists see even more contradictions. It is well established by many, many measurements that the contribution of CO2 to atmospheric composition does not change with altitude, for example. Check elsewhere on this site for proof of that. -
HumanityRules at 10:37 AM on 12 May 2010Estimating climate sensitivity from 3 million years ago
71.doug_bostrom Where is clouds on your image? -
Estimating climate sensitivity from 3 million years ago
johnd, re "That rate is not directly because of the CO2, but because of the water vapour which responds directly to temperature" Not so, CO2 is also a greenhouse gas albeit a less powerful one. This is how the feedback cycle starts in the first place. In any case, as you stated, water vapour acts as a feedback due to any increase in temperatures. The size of the feedback is relative to the size of the increase. Waste heat only increases earth's temperature relative to the increase in the amount of waste heat from one year to the next. A constant rate of waste heat will be quickly balanced out by heat dissipation to space and contribute nothing new to warming. So to estimate how much waste heat contributes to warming, you need to look at how much the rate of waste heat has increased, not how much total heat has been pumped out. This is different than CO2, where every extra molecule of CO2 essentially increases the warming rate. As a result, CO2 emissions have a cumulative effect year to year. In short, the key difference is: when you look at waste heat, you're looking directly at the amount of heat added to the climate. When you're looking at CO2 emissions, you're looking at an increase in the rate of heat being added to the climate. -
johnd at 08:00 AM on 12 May 2010Estimating climate sensitivity from 3 million years ago
Riccardo at 07:40 AM, as you know I asked for confirmation of the figure, nobody has come up with a different figure yet. If you have a different value please don't keep it a secret. The formula that yielded the value I posted is current forcing = log2(1+2/385)W/m2 based on 385ppm adding 2ppm annually. You can find it here. http://www.physicsforums.com/showthread.php?t=307685 -
maintain_integrity at 07:58 AM on 12 May 2010Climate Change and the Integrity of Science: a letter to Science
@geo guy, #201: edward long & SPPI After reading the ad hominem attacks by edward long in his non-peer-reviewed work of fiction at SPPI, I think you need to read a sane description of temperatures -
Riccardo at 07:40 AM on 12 May 2010Estimating climate sensitivity from 3 million years ago
"By the way, the issue of whether waste heat is an important factor in global warming is one of the questions most commonly asked by students who are first learning about energy budgets and climate change. So, there are no shortage of places where you can learn about this sort of thing." Ray Pierrehumbert johnd, by the way, you have the number for the 2 ppm forcing wrong, at least at current CO2 level. You didn't like the aproximate formula I gave you but definitely you should use it. -
Doug Bostrom at 07:29 AM on 12 May 2010Estimating climate sensitivity from 3 million years ago
Pointless comparison. Here's a handy picture, so we can see what we're really talking about:
How does "about 0.027W/m2" stack up, compared to additional C02?
Please, enough on this. It's cooked.
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scaddenp at 07:29 AM on 12 May 2010Climate Change and the Integrity of Science: a letter to Science
With regard to mixing of CO2 - very short term concentrations of CO2 occur but molecular weight has little influence on gas mixing. However, on long term scale atmosphere is well mixed as you would expect from gas laws. The vertical profile of gas concentration in atmosphere has been well studied and only in stratosphere do get a reduction -
scaddenp at 07:21 AM on 12 May 2010Climate Change and the Integrity of Science: a letter to Science
"scaddenp # 214 - while there are models used to predict ENSO events, my reference was to the global climate models" So was mine. We do have a very good explanation (model) of what causes ENSO events. See the NOAA ENSO site. There is no mystery here - just very difficult to predict. The point I am making is the ENSO event are emergent from the physics of atmosphere and ocean, and the global climate models model capture this physics sufficiently well for ENSO event to emerge from the model as output. They are not "caused" by CO2 except in the sense that CO2 levels stop the ocean freezing. We would have ENSO events with stable CO2 levels. They are however part of the heat redistribution system. Since they are not some magical generator of energy, only a distributor, then how should they be an input to models? -
scaddenp at 07:03 AM on 12 May 2010Estimating climate sensitivity from 3 million years ago
"Shaviv and Veizer (2003) " Try looking at earlier assessment reports where odd stuff is discussed and discounted on basis on new research. It's not revisited in later Assessment reports unless there is new papers. -
johnd at 06:59 AM on 12 May 2010Estimating climate sensitivity from 3 million years ago
That figure 0.027W/m2 was based on 2002 energy figure of 13.76TW. If that is now 16TW, the 0.027W/m2 would now be 0.031W/m2. -
johnd at 06:52 AM on 12 May 2010Estimating climate sensitivity from 3 million years ago
doug_bostrom at 06:08 AM, I think the point being made is that the average annual heat energy input from energy consumption, about 0.027W/m2, is large compared to the heat energy prevented from escaping for the additional 2ppm of CO2 added annually which is about 0.0075W/m2. -
johnd at 06:33 AM on 12 May 2010Estimating climate sensitivity from 3 million years ago
e at 05:55 AM, re "As the level of CO2 in our atmosphere rises, the rate at which heat dissipates into space continues to go down." That rate is not directly because of the CO2, but because of the water vapour which responds directly to temperature, and also absorbs and transmits IR radiation over a much wider band than CO2 or any other greenhouse gas. If CO2 has been calculated as having a long residency time, what is the residency time of water vapour. Even though there is a high turnover of individual molecules, water vapour as a gas has residency time beyond measurement, a permanent presence that will exist whilst warmth from any source rises from the earth's surface. -
KR at 06:32 AM on 12 May 2010Estimating climate sensitivity from 3 million years ago
RSVP, you bring up thermal emissions and their contributions to global temperatures; keep in mind that GHG's change the steady state condition of the Earth's temps, not just the current temps. If the Earth's temp rises above steady state values, it will lose more energy to space (long wave IR energy) than we gain from the sun, and the temps will drop. Industrial thermal energy is not cumulative over the long term. In fact, if industrial heat contributions were the main cause of global warming, the energy imbalance at the top of the atmosphere would be positive - more energy coming from the earth than it receives, as the Earth tried to return to a steady state condition. That's NOT the case: A negative imbalance indicates energy trapping, not energy production, and that should invalidate the industrial energy->global warming hypothesis. -
Tom Dayton at 06:23 AM on 12 May 2010Estimating climate sensitivity from 3 million years ago
The waste heat argument is not really on topic for this post. John does not have an "Argument" post for waste heat, but he does have a set of links for it, with at least one good article linked there. I think everybody should stop commenting about that topic here, but should pitch in by suggesting additions to that Links page if you've got relevant material. -
NewYorkJ at 06:12 AM on 12 May 2010Climate Change and the Integrity of Science: a letter to Science
As others have pointed out, the NAS consists of a very broad set of individuals, many with little knowledge or experience with climate science. So it's not a surprise that the letter seeks support from those with the strongest knowledge. They might look for more broad support for statements like this: "We also call for an end to McCarthy-like threats of criminal prosecution against our colleagues based on innuendo and guilt by association, the harassment of scientists by politicians seeking distractions to avoid taking action, and the outright lies being spread about them." One doesn't need a great depth of climate science expertise to support a statement like this. I would think that nearly every NAS member would support this or a very similar statement (although the harassment is not limited to politicians). The attacks on scientists is utterly disgraceful. On the other hand, many scientists are quite cautious about getting involved in anything that seems the least bit political. They do the research and let the science do the talking. -
Doug Bostrom at 06:08 AM on 12 May 2010Estimating climate sensitivity from 3 million years ago
RSVP, if you do some quick calculations you'll see that waste heat (I assume you're speaking of "cultural heat", heat from nuclear and chemical sources liberated by human activities) is remarkably small compared to heat from insolation, so small that it essentially disappears compared to insolation Surface insolation for Earth taking into account angle of incidence, atmospheric attenuation, diurnal cycle etc. is roughly 250MW/km2. The surface of the Earth is about 510,000,000 km2. So, about 127,500TW of total insolation. As a basis of comparison, the present total electrical generation capacity of our global attempt at civilization is about 16TW. -
Estimating climate sensitivity from 3 million years ago
RSVP, I don't think you are understanding Chris's point. As temperatures rise, the rate that heat dissipates into space also rises, until the rate of warming and the rate of dissipation equalize, and the climate is in equilibrium. As long as the rate of warming influences remains constant, there is no accumulation of heat. The problem with CO2 is it takes thousands of years for feedback mechanisms to balance out and remove CO2 to a significant extent. As a result, even if our CO2 emissions stabilized at the current annual level, CO2 would still accumulate in the atmosphere. As the level of CO2 in our atmosphere rises, the rate at which heat dissipates into space continues to go down. This has the effect of pushing the climate's equilibrium temperature ever higher. In contrast, if we could freeze the rate of waste heat at current levels, it would no longer have a continued effect on our climate's equilibrium level. The point is not that waste heat should be ignored, it's that its contribution is minor compared to that of CO2 emissions. In any case, reducing our reliance on fossil fuels would mitigate both issues. -
RSVP at 04:47 AM on 12 May 2010Estimating climate sensitivity from 3 million years ago
Chris Why go back only 100 years? 100 years or pre-Industrial Revolution is pretty much the baseline condition for the detected changes in CO2 ppm and average global temperature. This is what AGW is focussed on I believe. A "modern" event. What happened before this is irrelevant. Natural cooling may have absorbed/cancelled any significant anthropogenic contributions 20 times in the past for all we know. For the point I was making, I assume that the natural fluctuation is completely stable over the last 100 years. The only two things to consider then is effects of greenhouse gases and waste heat. But you cant ignore a cummulative effect of waste heat while at the same time holding everything else constant (and even worse, assuming that the IR lid is even tighter). So some of the warming must be attributed to waste heat. The other detail is that you have what is called winter and night. Either global warming is only associated with warmer days and warmer summers, or the heat is accumulating somewhere (and that somewhere is our oceans). -
JMurphy at 04:22 AM on 12 May 2010Kung-fu Climate
Likewise...although I doubt whether I initially posted anything more relevant ! As a final, final comment from me here (and I mean it this time), I want to congratulate this site, John Cook, all the article authors and most of the contributors for laying out all the arguments and answering all the skeptical queries (as far as I have seen, anyway). I learn something new every day on this site so I'm sorry to have been a part of dragging this thread into such a pointless and circular argument - especially as that is exactly what the so-called skeptics want.
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