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GCNP58 at 09:50 AM on 2 April 2011Soot and global warming
LJ: I agree with cbrock. Soot has a very positive greenhouse effect in the atmosphere. The imaginary part of the index of refraction plays a huge role in whether a particular aerosol will cool (scatter) or heat (absorb). The imaginary index of refraction for soot is huge. It heats, regardless of location. Soot-containing particles are implicated in closing some of the unknowns in radiative transfer in the atmosphere, where the measured scattering coefficients don't match what would be expected based on the inorganic chemical constituents (the imaginary index is way too high). However, small amounts of soot boost the imaginary index up, so that the scattering is less and the absorption is greater. Don't make those comments around aerosol chemists or radiative transfer specialists, they will be very forceful in telling you how wrong you are. If you do just a bit of googling on strings like "soot radiative impact atmosphere" you will clear up these misconceptions in very short order. -Bill -
Gilles at 09:39 AM on 2 April 2011A Plan for 100% Renewable Energy by 2050
just one thing : do you have an idea of how much oil we should find per year to insure 20 Mbl/d of "yet to be found" fields in 2030 ? -
Gilles at 09:38 AM on 2 April 2011A Plan for 100% Renewable Energy by 2050
Mucounter : I don't see clearly your point - I agree with most of what you say, but what do you try to prove against what I'm saying ? and why would it contradict the "back-of-the-envelope calculations" ? -
KR at 07:57 AM on 2 April 20112nd law of thermodynamics contradicts greenhouse theory
damorbel - I'm quite surprised to see you back. Have you read my posting here? Evaporation, convection, and the adiabatic lapse rate have all been covered in tedious detail on this thread; if you're interested, look it up. But (personal opinion) I do not consider it worthwhile to debate with someone who (like you) is willing to contradict your own posts in order to prolong an argument - that is trolling, not science.Moderator Response: While these topics have indirect relevance to the 2nd law and its relationship to the GHE, this thread is not intended as a substitute for a college level physics course. As you pointed out, these topics have already been covered here in excruciating detail. Future off-topic or repetitive comments will be deleted. -
damorbel at 07:42 AM on 2 April 20112nd law of thermodynamics contradicts greenhouse theory
Re #900 KR You wrote: "and that this absorption (by the 1st law of thermodynamics, conservation of energy) affects and slows the total, net energy transfer to the atmosphere and hence to space." You write about the 1st Law and radiation as if these were the only two energy processes involved - you take into account radiation only. But for a thermodynamic analysis you must include all forms of energy involved in the whole thermodynamic system that comprises the atmosphere. By confining your consideration to radiation only you may well get the answer you are seeking but that is hardly science! As I have mentioned before, you must also account for the gravitational energy of the gas that makes up the atmosphere; it is, after all, the gravitaional component that gives the troposphere its temperature profile (lapse rate) of -6.5K/km. Any attempt to may an 'energy balance' that doesn't include gravitational energy is not going to give an accurate picture. -
dana1981 at 06:53 AM on 2 April 2011Debunking Climate Myths from Politicians
Thanks JMurphy. Now we can get to work responding to the hearing. -
Stephen Baines at 06:47 AM on 2 April 2011Acidification: Oceans past, present & yet to come
Rob Painting...Yes, that was the paper I was talking about. It shows short term effects of acidification on Fe availability due to effects on binding strength of organic ligancs with fe(III). The Sunda article points out the caveats - like whether such a mechanisms will in the long terms increase the total amount of Fe by preventing scavenging of Fe(III) on sinking particles. -
JMurphy at 06:13 AM on 2 April 2011Debunking Climate Myths from Politicians
That House Climate Hearing seems to be available here, but having read some of the transcripts available at the link provided by chrisd3, it seems that the same old nonsense was repeated by all the usual so-called skeptics : including Christy's constant reliance on his own work and references to such 'authorities' as ClimateAudit, McIntyre (who he positively seems to idolise) and McKitrick; Armstrong's constant use of the terms 'alarm' and 'alarmism', and reliance on Soon; and Muller's references to Watts and his supposedly soon to be published (any day now, honestly) paper, while also showing how what Watts is claiming is actually disproved by the work being done by BEST. Same old, same old. -
muoncounter at 06:08 AM on 2 April 2011A Plan for 100% Renewable Energy by 2050
Gilles#143: "decrease of oil production will be driven by lower demand and reconversion to other energy sources, and not by geological availability" Oil production is driven in part by all those factors, but it is primarily driven by economics. Once the initial investment is made, the time value of money demands a targeted production schedule. Depletion inhibits production, so we often do not meet those targets. "exactly what happened in the 80's with the oil counter-shock, that provoked both a nosedive of barrel price" You can believe in shock/counter-shock models if you like. But we must have lived through different decades: the oil price drop of the mid-80's was a means of destabilizing the Soviet Union. Why else would half a million US jobs be sacrificed with hardly any notice outside the oil patch? "I'm saying nothing else for oil." That will help you from digging any deeper holes in what remains of your credibility. "I don't see why they would be "instructed" to say that we need to find new oil fields that we don't know yet where they are-" Borderline gibberish. We know where to find oil -- in oil-producing basins. The industry will not suddenly stop finding oil this year or in the next decade; the projection of 'oil yet to be found' expresses that confidence. It will simply become increasingly expensive to find and produce new oil - and that is what will inevitably make renewables economically attractive. "what's wrong with back-of-the-envelope calculations ?" They are usually incorrect. Yours are tantamount to "racecar on a train." -
cbrock at 05:59 AM on 2 April 2011Soot and global warming
RealClimate has an interesting discussion here of the downside of controlling soot in lieu of going after the big fish--CO2 regulation. -
Bjarne Mikael Torkveen at 05:46 AM on 2 April 2011Crux of a Core, Part 3... Dr. Ole Humlum
Being a Norwegian citizen, I know how the Norwegian climate deniers operate. Ole Humlum is a climate denier in the true meaning of the term. He is not as flexible as Rob Honeycutt might think. Don't be fooled by his "charm", Rob. He likes to spread confusion and misrepresentations. His favourite arguments are: "Global warming stopped in 2000", "it's the sun" and "it's cosmic rays". As the majority of the audience on this site speaks English, I can only supply a limited amount of articles featuring Humlum, but here's one: "Another Unfortunate Truth – Global Warming Stopped" -
cbrock at 05:38 AM on 2 April 2011Soot and global warming
LandyJim: Your statements are not factual. While overall, aerosol particles are likely to have a cooling effect due to increased scattering back into space and to increased cloud reflectivity, soot particles are different. They absorb light and heat the level of the atmosphere where they are found. Soot=black. When they combine with other particles to form a core surrounded by a nonabsorbing coating, their absorbing power can be almost doubled due to a lensing effect. There is a vast literature on these topics, almost all of which indicates that airborne soot has positive contribution to global warming. Adding to this is the effect soot has on snow by slightly darkening it, thus increasing the snowmelt rate and exposing the dark underlying surface to sunlight earlier in the spring. Again, lots of literature on these topics. Your bluster doesn't help promote your viewpoint. One of my fields of study; you don't want to get me going ;-) -
dana1981 at 05:27 AM on 2 April 2011Soot and global warming
LandyJim - this article refers to black carbon on the ground, not aerosols in the atmosphere. Please read more carefully next time. -
LandyJim at 05:17 AM on 2 April 2011Soot and global warming
What a load of rubbish, such bad science does not deserve funding. It is a fact that particulates in the atmosphere DECREASE global temperatures and not increase. Soot in the atmosphere increases cloud cover, increases the planet's planet's albedo and thus reflects more radiation back into space, causing the body of the planet and the lower atmosphere to cool. This has been amply demonstrated on Earth and Mars. On Earth Major volcanic eruptions have been conclusively shown to lower global mean temperatures and this has been shown to also occur when major dust storms on Mars cause the surface temperature to decrease. This is science {snip}Moderator Response: [muoncounter] Ease up on the accusations please; portions violating Comments Policy were snipped. If you have an opinion, please substantiate it more thoroughly than 'amply demonstrated'. -
johnd at 05:11 AM on 2 April 2011Arctic Ice March 2011
Sphaerica at 01:11 AM , you seem to have missed what the charts presented by DB were clearly emphasising. Three times with the three different charts the argument for the dominating role of incoming solar radiation was clearly reinforced. -
johnd at 05:03 AM on 2 April 2011Arctic Ice March 2011
Ken Lambert at 23:50 PM, given how so very very easy it would be to put the correct perspective into such depictions, it should be done as a matter of course instead of leaving it up to the viewer to visualise in their own mind, if they happen to twig that is. Another dissappointing aspect of the depiction was that it was centred on the calender year hence the boreal winter months. If instead the monthly values began 3 months earlier or later it would have allowed both the Arctic and Antarctic to be more readily compared. Of course the objective of the illustration was to emphasise the Arctic, however being able to more readily compare both poles would again have provided greater perspective for the viewer. Adjusting the time period to something other than the calender year is very often done for annual cycles in order to be depicted, and thus understood in their entirety without having the more critical peak or hollow cut in half at either end making appreciation of the cycle just that much more difficult. -
CBDunkerson at 04:13 AM on 2 April 2011A Plan for 100% Renewable Energy by 2050
Gilles: I'm just going to ignore your ongoing attempts to recast your errors as mine. "could you please find me a reference showing that any of these things would be manageable with 2 °C and not with 2.8 °C ?" See: Climate sensitivity -
Gilles at 03:44 AM on 2 April 2011A Plan for 100% Renewable Energy by 2050
mucounter - I'm saying nothing else for oil. Now if you think that the decrease of oil production will be driven by lower demand and reconversion to other energy sources, and not by geological availability, there is a very simple associated prediction : that prices should plunge and oil extraction will be given up because there aren't enough customers - that exactly what happened in the 80's with the oil counter-shock, that provoked both a nosedive of barrel price and a decrease of production/consumption - and this happened also very briefly just after the 2008 recession . But if the decrease is due to a lack or resources, you expect just the opposite : that the price will climb to heaven and that the high price will discourage customers to buy it -much probably through strong recessions and demand destruction. what's your favorite scenario ? concerning agencies : too bad that all sres scenarios are based on the numbers provided or used by the same agencies. But I don't see why they would be "instructed" to say that we need to find new oil fields that we don't know yet where they are- that's not good news for OECD ! and what's wrong with back-of-the-envelope calculations ? -
cjshaker at 03:39 AM on 2 April 2011Temp record is unreliable
Surprise! Professor Muller says that the IPCC temperature trend information is reasonable http://us1.campaign-archive2.com/?u=d8548cad5e5305433c810b0d4&id=fc86e0f3ab&e=36d50f5714 "In Summary Despite potential biases in the data, methods of analysis can be used to reduce bias effects well enough to enable us to measure long-term Earth temperature changes. Data integrity is adequate. Based on our initial work at Berkeley Earth, I believe that some of the most worrisome biases are less of a problem than I had previously thought." -
Rob Honeycutt at 03:16 AM on 2 April 2011Crux of a Core, Part 3... Dr. Ole Humlum
Gilles... You also might check out Dr Box's website which shows the modern temperature record for Greenland. You'll see that "no significant warming trend in the past decade" is demonstrably wrong. -
Rob Honeycutt at 03:10 AM on 2 April 2011Crux of a Core, Part 3... Dr. Ole Humlum
Gilles... You're in active pursuit of a straw man argument. I highly recommend you read the comments made by Dr Alley in Revkin's article that I linked above. -
muoncounter at 02:51 AM on 2 April 2011A Plan for 100% Renewable Energy by 2050
Gilles#135: "The peak in FF production is always governed by the offer, not the demand. No company stop drilling and extracting oil when the well is drilled, before it is exhausted." You've already demonstrated that you know nothing about the oil business; at least you're consistent because that's just false. Wells are abandoned when the economics turn unfavorable. If it costs more to produce than you can get for it, you stop producing. Gilles#141: "if it's true, why does all energy agencies seem to ignore it ?" Why do you assume it is the business of an 'energy agency' to do anything other than what they are instructed to do? In these cases, you've created some mythic significance from the presence of an 'oil to be found' term in an IEA forecast, fabricating a conclusion from it: 'They include it, so it must be vital to our society.' Nonsense. And now come the back-of-the-envelope calculations, which are of course based on complete understanding of energy use. This is the more appropriate xkcd for this situation. -
Gilles at 02:37 AM on 2 April 2011Crux of a Core, Part 3... Dr. Ole Humlum
Figure 3 clearly shows that variation of Greenland summit temperatures are * not* correlated with the variation of CO2 in paleoclimatic data (whatever this means - there is no obvious correlation). Given this objective fact, why use the current rise of Arctic temperatures as evidence for the influence of GHG ? Remarkably , the recent loss of Arctic ice is *not* related to a particularly high change in average temperatures. Actually the last decade has not shown any significant trend, and certainly not an acceleration.Moderator Response: [muoncounter] See global warming stopped in... for documentation that 'the last decade has not shown any significant trend' is false. -
Rob Honeycutt at 02:21 AM on 2 April 2011Crux of a Core, Part 3... Dr. Ole Humlum
Tom @ 6... Here is where I get some of the information regarding misuses of GISP2 data, and specifically the idea that snow drifts can cause some anomalous readings in the data. It's some material posted on Andy Revkin's Dot Earth blog.Second, although the central Greenland ice-core records may provide the best paleoclimatic temperature records available, multiple parameters confirm the strong temperature signal, and multiple cores confirm the widespread nature of the signal, the data still contain a lot of noise over short times (snowdrifts are real, among other things). An isotopic record from one site is not purely a temperature record at that site, so care is required to interpret the signal and not the noise. An extensive scientific literature exists on this topic, and I believe we are pretty good in the community at properly qualifying our statements to accord with the underlying scientific literature; the blogospheric misuses of the GISP2 isotopic data that I have seen are not doing so, and are making errors of interpretation as a result.
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Rob Honeycutt at 02:03 AM on 2 April 2011Crux of a Core, Part 3... Dr. Ole Humlum
RSVP... Please note that my Fig 4 graph is Holocene only. -
lord_sidcup at 01:16 AM on 2 April 2011Debunking Climate Myths from Politicians
@31 Regarding John Redwood, I had a look through his blog and it is an absolute goldmine of badly constructed straw men. Here is a quite bizarre quote from last year: "It was good to hear the scientific establishment today concede what some of us have been saying for a long time – that changes on the sun can have an impact on our climate. I look forward to sun variations being included in models forecasting changes to earth temperatures." Time to revise climate change models? Another UK politician to watch out for is one time Conservative Party leadership contender David Davies: Why this ferocious desire to impose hair-shirt policies? "The case is not helped by the fact that the planet appears to have been cooling, not warming, in the last decade." -
Chris G at 01:14 AM on 2 April 2011Crux of a Core, Part 3... Dr. Ole Humlum
I sometimes use logarithmic scales when I have small values and large values on the same graph. But, then, I also sometimes have trouble when viewers don't understand just how large the actual differences are when looking at said graph. -
Bob Lacatena at 01:11 AM on 2 April 2011Arctic Ice March 2011
58, Ken Lambert Yes, yes, of course. Nothing to worry about. All is well. It's only a tiny place, and it's cold and far away. Don't worry about the Arctic melting for the first time in tens (hundreds?) of thousands of years. Don't worry about global warming, people! It's nothing. It's all exaggerated alarmist tripe. The Arctic is small. The ice recovers every winter. Temperature records are unreliable. It's all natural. Et cetera, et cetera. How many thousands of excuses can the denial crowd come up with to justify coordinated collective irresponsibility? -
Gilles at 01:07 AM on 2 April 2011A Plan for 100% Renewable Energy by 2050
Bern, you deviate to other topics - I would like however to make you notice that "X and Y published dire predictions for Z centuries" is not per se a proof they're right. And even if it were true, saying that doesn't say nothing about the inverse consequences of suppressing totally the FF consumption of the very same people you are supposed to save. You can claim that the consequences are negligible, but I stick to my question : if it's true, why does all energy agencies seem to ignore it ? -
Arkadiusz Semczyszak at 00:35 AM on 2 April 2011Acidification: Oceans past, present & yet to come
I also recommend a very interesting discussion by Nature Blogs. -
Arkadiusz Semczyszak at 00:31 AM on 2 April 2011Acidification: Oceans past, present & yet to come
Paper above applies to the economically important species - and yet only one of the species - does not provide the basis for good general conclusions. How - in general - the organisms react to reduce the alkalinity of the oceans? I do not know if it was discussed at Sc.S. this paper: Meta-analysis reveals negative yet variable effects of ocean acidification on marine organisms, Kroeker et al., 2010. But it is worth recalling some of the conclusions of this paper: “A variety of biological responses to ocean acidification have been measured across a range of taxa, but this information exists as case studies and has not been synthesized into meaningful comparisons amongst response variables and functional groups.” “Calcification responses varied significantly amongst organisms using different mineral forms of calcium carbonate.” “... the responses of calcifying algae were highly variable.” “Our results support the hypothesis that highly mobile organisms with developed intracellular/extracellular pH regulatory mechanisms may be more resilient to ocean acidification.” “We did not detect significant effects of ocean acidification on photosynthesis in the overall weighted, random effects analysis.” “In conclusion, our analyses revealed a strong negative effect of ocean acidification on marine organisms despite the variation in the sensitivity of taxonomic groups and developmental stages. However, differential sensitivities still have important implications for marine ecosystems where individual species often play disproportionately strong roles in structuring communities ...” ... however wikipedia: “However, some studies have found different response to ocean acidification, with coccolithophore calcification and photosynthesis both increasing under elevated atmospheric pCO2, an equal decline in primary production and calcification in response to elevated CO2 or the direction of the response varying between species. Recent work examining a sediment core from the North Atlantic found that while the species composition of coccolithophorids has remained unchanged for the industrial period 1780 to 2004, the calcification of coccoliths has increased by up to 40% during the same time.” Increasing Costs Due to Ocean Acidification Drives Phytoplankton to Be More Heavily Calcified: Optimal Growth Strategy of Coccolithophores, Irie et al. 2010.: “Contrary to the widely held belief, the evolutionarily optimized population can precipitate larger amounts of CaCO 3 during the bloom in more acidified seawater, depending on parameter values. These findings suggest that ocean acidification may enhance the calcification rates of marine organisms as an adaptive response, possibly accompanied by higher carbon fixation ability. Our theory also provides a compelling explanation for the multispecific fossil time-series record from ~200 years ago to present, in which mean coccolith size has increased along with rising atmospheric CO 2 concentration.” Coral reefs and ocean acidification synopsis ISRS, Briefing Paper 5, 2008.: “Most experiments have not indicated negative impacts on coral tissue growth under elevated carbon dioxide. Indeed, recent experiments have shown that some species cultured under high carbon dioxide concentrations can lose their skeletons altogether without apparent physiological stress or reductions in growth, and then resume skeletal building once carbon dioxide levels are returned to normal.(...).” Impact of CO2-driven ocean acidification on early life-history – what we know and what we need to know, Dupont, Havenhand and Thorndyke, 2009.: “At the same time, more physiological studies are needed to understand contradictory results (e.g. species-specific responses in closely related taxa) and solve apparent paradoxes (e.g. positive impacts in notionally “at risk” species such as calcifying sea urchins). Ultimately, more realistic experiments (e.g. mesocosms, synergy with other environmental parameters, multigeneration, etc.) are needed to upscale experimental data to the ecosystem level. (...)” I also recommend a very interesting discussion by . -
JMurphy at 23:54 PM on 1 April 2011Debunking Climate Myths from Politicians
In addition to the above, there is no need for this site to debunk Lawson (as if it was even necessary, I know), because the British chief scientific advisor, Sir John Beddington has already done so, as seen in letters that have just been released. -
Ken Lambert at 23:50 PM on 1 April 2011Arctic Ice March 2011
johnd #54 and #56 MC #57 Quite right again johnd. Many of these charts showing large red areas of warming are Mercator projections which grossly distort the high latitudes and infinitely expand the north and south poles to the same dimension as the equator. Without an equal area projection, the proper scale of the Arctic is not obvious to the non-geographer. DB's Insolation chart captioned; "The Arctic in summer receives more daily energy from the sun, both at the surface and the TOA, than does the equator" is also misleading. What DB should have captioned is that the Insolation (energy flux)at TOA for May, June ,July is higher than at the equator, but the total energy available (W/sq.m x Area in sq.m) is small compared with the tropics due to the small surface area above 60N and the much higher average insolation through the whole year at tropical latitudes. -
Bern at 23:46 PM on 1 April 2011A Plan for 100% Renewable Energy by 2050
Gilles, it wasn't intended to be ad hom, rather humorous (thus the XKCD ref and the smiley face :-). I'm happy for a mod to delete it, though, if you feel it's ad hom. Regarding the methane emissions - I just did a bit of searching, and the total amount is staggering - estimates vary from ~1,000 GtC to ~1,000,000 GtC locked up in permafrost & clathrates. Luckily for us, it seems that only a small part of that is likely to be released - one paper I found suggested it might only increase GHG forcing by ~10-25%. (phew!) On the other hand, there is significant evidence that the melting process has already started. Regarding the "safe" level of GHG: there are a number of climate scientists who think that it's more around 350ppm - meaning we need to *remove* CO2 from the atmosphere, rather than add to it. Hansen & Sato's recent paper [pdf] certainly makes a strong argument that a 450ppm target will lead to dramatic changes in climate and significant sea level rise (on the order of 4-6 metres or more). -
Gilles at 23:20 PM on 1 April 2011A Plan for 100% Renewable Energy by 2050
"ln(450/280) * FF = 2.05C Your '540 ppm is safe' view would instead put us at about 2.8C over pre-industrial levels... which most projections indicate would cause changes in sea level, freshwater supplies, and cultivatable land at a pace many nations would not be able to handle" could you please find me a reference showing that any of these things would be manageable with 2 °C and not with 2.8 °C ? is the 2°C some magic limit - it's fortunate that the Celsius scale gives suche an easily rememberable figure ! -
Gilles at 23:17 PM on 1 April 2011A Plan for 100% Renewable Energy by 2050
CBD If you ignore the amount of carbon we're burning each year, I think you'd better refresh somewhat your readings. Actually it is a little bit less than 10 with FF only, a bit more including deforestation, but i'm only doing back-of-the-envelope calculations. 2000Gt/30 = 67 years approximately (not 200), giving 133 ppm more at the current rate, so it's more 520 ppm - I took 540 for a conservative estimate including methane, deforestation, and so on - CO2 is always the main driver. I don't expect runaway methane emissions with such a level- please correct me if you know a valid reference that says the opposite. Now I took only the transient response in 2100 , that's why I didn't take the full 0.8 °C - 0.5 °C is an order of magnitude. For slow feedbacks, you have to take into account that the CO2 will also decrease with time with the slow reabsorption by the wells after the production has decreased - the whole temperature curve must be numerically integrated but I don't expect it will vary much after that. and as everybody knows, in 2100, we'll have found a lot of solutions to compensate for the loss of FF - which means in theory no limit for developing the whole mankind since finite stock resources won't be a problem anymore. I don't see why, if all mankind has become rich , it couldn't mitigate the impact of CC just as rich countries can do it currently. -
JMurphy at 23:06 PM on 1 April 2011Debunking Climate Myths from Politicians
Lawson was at it again recently, in the Spectator 'debate' in London. As usual it was non-scientific so-called skeptics (Lawson and Peiser from the GWPF, plus a Labour MP), arguing against scientists (Tim Palmer, David King, Simon Singh). Although the audience was mainly Spectator types, it would appear that more people were convinced of the dangers of AGW after the debate than before. -
CBDunkerson at 22:51 PM on 1 April 2011Muller Misinformation #1: confusing Mike's trick with hide the decline
Gilles: "Fine : if they are, the we can deduce with a great confidence from Fig 3 that most of the XXth century temperature rise has occurred before 1970, so it must be perfectly natural." Actually Fig 3 shows that unicorns are real and that therefor we no longer have to worry about cancer. No, I can't really back that up... but it bears about as much resemblance to reality as your description of the graph. -
CBDunkerson at 22:42 PM on 1 April 2011A Plan for 100% Renewable Energy by 2050
Gilles, actually the '10 Gt/yr' value was yours too. Like I said, I didn't check your numbers... just pointed out that the math doesn't work. At that, if we change 10 to 30 it still doesn't come out to 540 ppm. You don't give the calculations for how you get to 540 ppm only causing a 0.5 C increase over 450 ppm, but >my< 'back of the envelope' calcs would go something like this; At best estimates of climate sensitivity a doubling of CO2 is expected to cause 3C warming from fast feedbacks (FF) and 6C warming from slow feedbacks (SF). Ergo; FF * ln(2) = 3 -> FF = 4.33 SF * ln(2) = 6 -> SF = 8.66 ln(540/450) * FF = 0.79 C ln(540/450) * SF = 1.58 C So again, your 'abbreviated math' doesn't seem to match up. I was actually able to 'follow' your conclusion that 700 * 3 = 2000, but from there it seems to get progressively less accurate. For the record, the 450 ppm figure was derived based on a goal of limiting fast feedback warming to 2C over the pre-industrial level. We can use this to validate my formulas above; ln(450/280) * FF = 2.05C Your '540 ppm is safe' view would instead put us at about 2.8C over pre-industrial levels... which most projections indicate would cause changes in sea level, freshwater supplies, and cultivatable land at a pace many nations would not be able to handle. -
CBDunkerson at 22:09 PM on 1 April 2011Crux of a Core, Part 3... Dr. Ole Humlum
Yeah, that 'rate of atmospheric CO2 change' graph ought to be added to the 'CO2 increases are natural' rebuttal. I knew that CO2 increases of about 100 ppm took thousands of years throughout the interglacial cycle as opposed to mere decades now, but seeing that represented visually really drives the point home. The only 'problem' with the graph is that natural rates of change have always been so small in comparison that they are practically invisible at this scale. It might be worth having a 'blowout' at a more detailed scale to show that there were natural variations going on... they were just insignificant compared to the current human driven change. -
pkm at 20:55 PM on 1 April 2011Crux of a Core, Part 3... Dr. Ole Humlum
@9 RSVP, that graph shows the rate of change rather than the CO2 levels themselves... It is indeed a stunning perspective, that I will incidentally use in a few weeks in a presentation on CO2. I calculated the other day that current CO2 increase is about 2 ppm per year, whereas the increase rate during the last deglaciation was in the order of 0.007 ppm per year. More than 2 orders of magnitude smaller! -
Gilles at 19:49 PM on 1 April 2011Muller Misinformation #1: confusing Mike's trick with hide the decline
"There's an entire research field devoted to dedrochronology, and there's strong evidence that in most cases, tree rings are a good temperature proxy." Fine : if they are, the we can deduce with a great confidence from Fig 3 that most of the XXth century temperature rise has occurred before 1970, so it must be perfectly natural. -
RSVP at 19:06 PM on 1 April 2011Crux of a Core, Part 3... Dr. Ole Humlum
To Rob Honeycutt as per graph posted in pbellin 3 For all practical purposes, the CO2 level is completely flat in your graph. Should'nt it contain oscillations that reflect past ice ages? What the graphs seems to transmit is either we never had any ice ages, or if we did, CO2 ppm has no bearing on temperature. The great spike at the right also suggests this even more when you consider how little temperature has changed in recent years.Moderator Response: [DB] The graph of which you speak is clearly labelled as depicting the rate of change per century. As such it is a direct, apples-to-apples comparison between time periods. Apologies to the Bard, but "Context is the thing." -
Glenn Tamblyn at 18:37 PM on 1 April 2011Of Satellites and Air – A Primer on Tropospheric temperature measurement by Satellite
Daniel. If we have a supervolcano, then we can take AGW of the table as an agenda item for a while. And I will probably stop saving for my retirement. How can I spend my (very limited) wealth in a way that gives me the most fun before I croak?Moderator Response: [DB] Given the effects, if that supervolcano is Yellowstone here in the US, I might only have a few months. But the likelihood is far less than the temperature forcing from CO2. :) -
Stu at 18:05 PM on 1 April 2011Debunking Climate Myths from Politicians
"I believe Mr. Sarkozy is technically correct." The best kind of correct! Cheers Futurama. However, that doesn't mean he's not also wrong, sort of, cos it misses the point. Colder stratospheric temps would have only a small effect on ozone concentrations were it not for all the halogenated compounds we put there. I've been struggling for a decent analogy... maybe it's like leaving you freezer open and worrying that your kitchen is now a bit chilly, ignoring that all your food has gone off and the floor's just about flooded. Erm... yes? -
Rob Painting at 17:55 PM on 1 April 2011Acidification: Oceans past, present & yet to come
Agnostic @ 26 - Steve Baines may be referring to this paper Effect of Ocean Acidification on Iron Availability to Marine Phytoplankton. I don't have a copy, but it is discussed in sufficient depth here. -
Gilles at 17:34 PM on 1 April 2011A Plan for 100% Renewable Energy by 2050
" Given Gilles' persistence in posting here, and the content of the messages, I feel we're seeing one of two things: a sock-puppet, or someone who really believes what they're posting, a la this XKCD comic. Personally, I hope it's the latter. :-)" just a question for moderation : does this belong to the class of "ad hominem comments" , or not ? -
Gilles at 17:33 PM on 1 April 2011A Plan for 100% Renewable Energy by 2050
scaddenp, you asked me to answer your question, i did. CBD has obviously confused CO2 and toe or C when he wrote 2,000 Gt CO2 / 10 Gt/yr = 200 years since we produce around 30 GtCO2 and not 10 (this is the energy consumption). everybody can do mistakes, but it is extraordinary that it requires an explanation PLUS another justification for people claiming I'm not acting like a scientist. Mucounter : there is no mistake, I said 0.5 °C with respect to the the lowest reasonable value expected in 2100, not with respect to now. Please read me more carefully. The problem in saying "the threshold of 2°C is dangerous and we must keep below it" is that even then natural variability of a few tenths of degrees corresponds to dozens of Gt of C, if not hundreds ; so you cannot define with precision the moment when you're supposed to stop. In the Ecofys scenario, they just offer a possible (probably unrealistic) future production, but they are totally silent about how insuring it for sure in the future : who will tell whom that it's enough and that he should stop now using FF ? this is just the product of sim-city formatted brains who believe the world is in their computers (I'm afraid many climate scientists suffer from this disease) . The peak in FF production is always governed by the offer, not the demand. No company stop drilling and extracting oil when the well is drilled, before it is exhausted. The only fact that will limit the extraction (and is acting just now for the oil) , is just that the resource becomes so expensive that the number of customers decreases : you're just seeing it's happening, but you don't seem to understand it. Please, again, come back in the real world. -
Bern at 16:32 PM on 1 April 2011A Plan for 100% Renewable Energy by 2050
If you're doing back-of-the-envelope calculations, don't forget the methane from clathrates & permafrost... from memory, the permafrost component alone is supposed to add another 1,500 Gt of carbon all by itself - but in the form of methane, which is ~77 times worse than CO2 over 20 years, and 25 times worse over a century. Add that to the 2,000 Gt of CO2 from humans, plus methane from clathrates, plus increasing temperatures turning sinks like rainforests & the oceans into net sources (and releasing significant amounts of the previously-absorbed human emissions) and we could be looking at some serious increases in greenhouse forcing. Having just read the last 70-odd posts on this thread, it is clear that Gilles is arguing for continued use of fossil fuels, primarily because we don't currently price the externalities, and as a result it's currently the cheapest source of energy. Spoken like a true economist who doesn't believe global warming poses any threat whatsoever to human civilisation. Actually, I'd go further, to say it sounds more like what you'd hear from an accountant, rather than an economist. Given Gilles' persistence in posting here, and the content of the messages, I feel we're seeing one of two things: a sock-puppet, or someone who really believes what they're posting, a la this XKCD comic. Personally, I hope it's the latter. :-) -
WheelsOC at 15:53 PM on 1 April 2011Crux of a Core, Part 3... Dr. Ole Humlum
Funny how a few visual aids can help put things in perspective. Figure 3 was a nice touch.
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