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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. -
Alexandre at 03:56 AM on 12 May 2010Heat stress: setting an upper limit on what we can adapt to
Maybe an interesting further step would be comparing map B with the map of future scenarios likethis one:
Southeastern Asia seems to be already close to the edge, and the few extra degrees of projected warming could make it exceed the tolerable limit. South America and sub-saharian Africa also seem vulnerable.
Let´s also keep in mind that this map here is the temperature anomaly for the period 2070-2100 (scenarios A2 and B2). Temperature does not stabilize there, though. Warming is expected to continue in the coming centuries.
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TOP at 03:52 AM on 12 May 2010Heat stress: setting an upper limit on what we can adapt to
I remember traveling in the Gangetic plain when it was 120F. It was nice. No mosquittoes or flies. They all died so we didn't have to use a net to sleep. Hot day and night. Just keep a watermelon handy. One little appreciated fact is that the global dew point is rising 3x faster than the global temperature. When the two meet the problem is solved. -
Ned at 03:48 AM on 12 May 2010Estimating climate sensitivity from 3 million years ago
HR, let me turn around your implied question: why do you think so many "skeptical" papers about climate sensitivity have turned out to have serious flaws? I take it you don't dispute Schwartz's own revisions to his original paper, and I assume you're likewise willing to accept that the problems with Chylek (see here and here) are real. Everybody including Roy Spencer seems to agree that there were significant problems with Lindzen and Choi. I would assume that the reason for this "pattern" is presumably that climate sensitivity really is somewhere around 3C, so papers that find much lower values understandably must have flaws or they wouldn't have found such an anomalously low value. Do you have a different explanation to suggest? Or another question: are there high-quality papers published in the peer-reviewed literature in the past decade that you would point to as convincing and that give a climate sensitivity below 2? I'm not aware of them, but maybe I'm missing something. -
Ari Jokimäki at 03:22 AM on 12 May 2010Estimating climate sensitivity from 3 million years ago
The "pattern" arises quite naturally, I think. Whenever there's some value being measured, one wishes to explain the outliers. Therefore the studies reporting values outside the regular range are more likely to be checked more thoroughly than the papers giving values within the regular range. It doesn't mean that the papers within range are not checked at all, it just means that papers outside the range are checked more thoroughly to find out why they find such strange values. As we have seen here, there are lot of papers that have determined the value of climate sensitivity. In that kind of situation there's not much chance that couple of outliers would be correct (and dozens of others would be wrong), so it's not surprising that we keep finding errors among them. -
Doug Bostrom at 03:00 AM on 12 May 2010Heat stress: setting an upper limit on what we can adapt to
I found this paper very interesting in the way it establishes a fairly uncontroversial boundary or limit of "adaptability" to global warming. Retreating from areas of the globe where we evolved is adaptation, sure, but could hardly be termed a success story. As Ned mentions this won't be a smooth process. Given less extreme conditions than those hypothesized in the paper we'll nonetheless witness unacceptable excursions, presumably with those excursions becoming more frequent and obvious the closer we actually do approach the extreme case. Time to begin breeding dogs with longer tongues... -
chris at 02:38 AM on 12 May 2010Estimating climate sensitivity from 3 million years ago
HumanityRules at 01:53 AM on 12 May, 2010 HR, Schwartz's paper has got nothing to do with volcanos [*]. So the point you are making is pointless. In any case Schwartz himself recognised that his analysis was flawed, and wrote a retraction in which his reanalysis brought his estimated climate sensitivity back into the IPCC range. Are you suggesting that we should continue to include his original analysis in our summary of the science on climate sensitivity even though Schwartz himself says it's incorrect? That would be taking efforts to misrepresent the science to truly heroic proportions! As for the 2007 IPCC report. It's rather unlikely that a 2007 IPCC report would include very much of the scientific literature from nearly 20 years previously. This early literature will have been consolidated in reviews, and in any case the role of the IPPC's periodic reports is to bring the state of knowledge of relevant science up to date. The Shaviv and Veizer (2003) paper is probably unlikely to have been cited by the IPCC ('though it might have been - why not have a thorough look?). It's really a hypothesis (note the title: "Celestial driver of Phanerozoic climate?" - incidentally the answer is almost certainly no!) and was published in the GSA house journal GSA Today which isn't considered part of the scientific literature (it's not indexed by ISI for example); that's not to say it isn't an excellent magazine btw, nor that the Shaviv Veizer hypothesis wasn't interesting). In any case Veizer subsequently reanalyzed his paleotemperature data, and the hypothesis pretty much fell flat. As for your "struggles with patterns forming", it's difficult to konw what to say. Of course if we're interested in the science then we're really interested in the evidence, and perhaps your struggles involve a difficulty getting to grips with that. It would help perhaps if you were to look at the papers you refer to... ------------------------------------------- [*] He estimates heat capacity response of the oceans from an analysis of ocean heat uptake, and he estimates a time constant for heat uptake by autocorrelation of the heat capacity during 1880-2004. How can you comment on this paper if you don't know what it's about? -
CBDunkerson at 02:26 AM on 12 May 2010Estimating climate sensitivity from 3 million years ago
RSVP #55, setting aside the incorrect atmospheric CO2 figures... your math is also off. The statement that a doubling of CO2 without feedbacks causes a 1 C increase in temperatures can be mathematically expressed as; X * ln(2Y/Y) = 1 C Where X is a constant and Y is the starting CO2 level. Plugging in your values we get ln(380/250)=0.41871. The natural log of 2 (from a doubling, 2Y/Y) is 0.693147. If 0.693147 X = 1 C then 0.41871 X = 0.6 C, not the 0.76 C value you came up with. 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. Not to mention consistent with both models and reconstructions of past climate change. -
Geo Guy at 02:21 AM on 12 May 2010Climate Change and the Integrity of Science: a letter to Science
Stephen Baines - 219 My numbers were for the US only, hence the reference to the EPA so I stand by them. With respect to CO2 being heavier than air, it does tend to fall and collect near the earth's surface - sometimes in great quantities. Volcanists are very aware of this danger when undertaking field studies. Then there is the high concentration of CO2 near Mammoth California that were so concentrated it killed trees. pubs.usgs.gov/fs/fs172-96/ Over time I contend that SO2 does have a greater effect on ocean acidity simply because the acid lakes and rivers eventually make their way to the ocean where currents distribute the waters with low pH around the oceans. As for residence time, I disagree as a gas with a lower specific gravity and lower solubility in rain water will stay in the air longer than one with a much higher solubility and a specific gravity that is 50% higher.. robhon # 218 - personally I am at a disagreement with the work done by the IPCC - for a number of reasons which probably should not be posted here as it would be deemed to be off topic. Suffice to say I have investigated the resolutions by the UN that created the organization and from that point on I've seen enough to be dissuaded by their work. scaddenp # 214 - while there are models used to predict ENSO events, my reference was to the global climate models and the integration of the forecast of ENSO events into the climate models. To be properly treated, they should be an input parameter and not an output - of course if they did that, then their models would appear to be out of whack. IF the ENSO events are a result of high levels of CO@, then I agree they would be an output. But since we do not know the origins of them (what causes the features that create the warming and cooling trends) we must conclude that their cause is something other than CO2 and hence they should be an input item -
Dikran Marsupial at 02:00 AM on 12 May 2010Kung-fu Climate
Likewise :o( -
HumanityRules at 01:53 AM on 12 May 2010Estimating climate sensitivity from 3 million years ago
#51 Chris Thanks for pointing those out. It's not straightforward but I had a look see if any made the cut in the 2007 IPCC report. Couldn't find them. Shaviv and Veizer (2003) Washington and Meehl (1989) Mitchell and Ingram (1989) Gillard and Schneier (1984) Idso (1980) More generally I struggle with a pattern that is forming in which any paper that estimates low sensitivity has huge flaws in it while those with estimates around the IPCC range are uncritically accepted. As an example in John's previous list Schwartz is critisised partly on the basis that it uses volcano's which may have different features to other forcings. Yet this is not raised earlier in the list for the Bender 2010 paper (which just happens to have a more acceptable value). It also didn't stop the IPCC from referencing other papers on volcano's or including a whole section on it. http://www.skepticalscience.com/climate-sensitivity.htm http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch9s9-6-2-2.html -
Miriam O'Brien (Sou) at 01:45 AM on 12 May 2010Heat stress: setting an upper limit on what we can adapt to
The difficulty with air conditioning is that most household air conditioners are only rated up to about 41C, some to 43C I think. When the temperature rises to 51C for any length of time, like a summer heat wave, we'll either have to invent better air conditioners and de-humidifiers or find another way to keep cool. (That's only 4C warmer than it got to in the heat wave in Melbourne in southern Australia last year - and the global temperature is still climbing.) Maybe building underground like at Coober Pedy will help. -
J Bowers at 01:36 AM on 12 May 2010Kung-fu Climate
Apologies for getting involved in the ding-dong, especially as I initially posted something far more relevant. -
chris at 01:28 AM on 12 May 2010Estimating climate sensitivity from 3 million years ago
RSVP at 00:19 AM on 12 May, 2010 Not really RSVP. Your analogy isn't a meaningful one in context. Here's an appropriate analogy. You live in one room shack in the woods. Your shack is cold (it's the same as ambient temperature) and therefore you light a fire in the fireplace and arrange that this provides a constant thermal output (the equivalent of human "waste heat"). The temperature of the shack rises a bit and stabilises at a temperature whereby heat from the fire is balanced by loss of heat to the outside. Note that although "energy cannot be destroyed", it isn't accumulating in the shack. The temperature doesn't keep on rising! The energy is dissipated to the outside. You decide that you find the situation still uncomfortably cold. You therefore put a layer of insulation on the outside walls (the equivalent of enhancing the greenhouse gas concentration in the atmosphere). The dissipation of thermal energy to the outside is less efficient and the temperature inside your shack rises until a new equilibrium temperature is reached. Since you quite like the effect you keep on adding to the insulation. Each time the added insulation provides an additional increment of prevention of heat loss and the temperature continues to rise. etc. etc. Note btw that if you were to take your scenario to its logical limit then the accumulation of heat in the Earth system would be unbearable. Why go back only 100 years? If energy was "accumulating" then the preceding millenia of forest fires, heat from volcanic eruptions etc would have turned the planet into fiery hell. Happily, the Earth is in radiative balance with its surrounds (at least it tries to be!), and forcings don't result in the continual accumulation of thermal energy; they result in the movement of the Earth system to a new equilibrium state. The equilibrium state resulting from human "waste heat" is a tiny fraction of a degree above the Earth surface temperature that would exist without it.... ...incidentally, 100 years ago the atmospheric [CO2] was ~ 300 ppm (not 250 ppm). So you need to recheck your maths... -
mike roddy at 01:27 AM on 12 May 2010Heat stress: setting an upper limit on what we can adapt to
It's going to be worse than what these studies indicate. I spent a lot of time in Delhi about 10 years ago, which falls within the pale red zone, due to local humidity. 45C was common, and people were barely able to deal with it. If there was a heat wave, people slept on roofs and sidewalks at night, and avoided exercise in the day. I don't think that we have much experience with 48C in a humid climate with few breezes, as in north central India. Mortality is likely to be very high, and there will be more emigrants than from Bangladesh, which has a smaller population that can more easily move to higher ground. The Himalayan foothills are already heavily populated and deforested. I've also lived in 50C weather, in the Southern California inland desert, which may be the hottest region on earth by temperature. Delhi was much worse, and the area is obviously far more populated. I'm glad you're bringing this up, John- this problem is quite overlooked, since it's simpler to talk about rising tides. -
MarkR at 01:18 AM on 12 May 2010Heat stress: setting an upper limit on what we can adapt to
Wow, that's something I'd never considered before! I'll certainly look it up. @Arkadiusz: interesting point. In the Cretaceous it appears there was a weird equator-pole temperature gradient. Perhaps new mechanisms (increased cyclone activity to redistribute heat perhaps?) could counter some of the dangers raised in this paper. I must read more! @factfinder: you're making the common mistake of confusing weather and climate. John did a little article on this. Currently we're going through (globally) the second warmest 12 month period ever recorded, according to satellites, despite a record solar minimum. Europe and the US have been reasonably cool though, for various reasons (winter was thanks to the Arctic Oscillation, f'r'instance).
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