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Papy at 23:03 PM on 17 June 2011Speaking science to climate policy
#13 "Hansen has been calling for a satelite to measure aerosol contributions since at least 1990 and estimates in the paper I linked at 7 that such a mission would cost only $100,000,000. For various political reasons it has never been launched." Wasn't it the mission of the crashed Glory satellite though ? -
Eric (skeptic) at 22:59 PM on 17 June 2011CO2 has a short residence time
Thanks for the feedback. Yes, I understand impulse response times from engineering, but in engineering one does not generally black box the system being studied and just measure current and voltage. However the CO2 system should be treatable as a passive system to a point (extreme warming may turn it into an active system) -
MoreCarbonOK at 22:55 PM on 17 June 2011CO2 – Some facts, figures and outcomes
Ja, but exactly how much is the cooling caused by CO2? What everyone forgot is that carbon dioxide also takes part in the life cycle. CO2 is taken up by the plants and the trees who then take warmth from their surroundings to grow. That is what you call an endothermic reaction. I noticed this when I happened to enter a forest at dawn = you could clearly feel that the forest was cooler and that it was taking energy from its surroundings. I mean did you ever see a forrest grow where it is very cold? Up until now, nobody, including the IPCC and all those more beautiful learned people, could put a figure to the cooling caused by the CO2 in this way. In fact, they had all forgotten about it. There are more issues like that. http://www.letterdash.com/HenryP/more-carbon-dioxide-is-ok-ok -
Tony Noerpel at 22:50 PM on 17 June 2011CO2 Currently Rising Faster Than The PETM Extinction Event
Rob Thanks. I was not referring to the figure in your post. The 44 Mya spike reference comes form a paper by Hansen and Sato [1] and I don't know if it has been published yet, but Hansen has used similar figures in several of his papers. All of Hansen's stuff is available on his web site. I appologize for making you do extra work but I assume you are more familiar with Hansen's work than I am. As I look at the figure, the spike may be closer to 42 Mya. Anyway, this more recent spike actually looks stronger than PETM and I'd always been curious about it. Again appologies for the confusion. Tony [1] James E. Hansen and Makiko Sato, Paleoclimate Implications for Human-Made Climate Change, NASA Goddard Institute for Space Studies and Columbia University Earth Institute, New York -
Robert Murphy at 22:46 PM on 17 June 2011The greenhouse effect is real: here's why
You completely ignored my question. Why did you write the same exact post on two threads? -
MoreCarbonOK at 22:40 PM on 17 June 2011The greenhouse effect is real: here's why
Henry@Robert 1) in the case of the confidence interval: the question whether the warming is significant on a 1%, 2.5 % 5% or or 10% is irrelevant. We know warming ihas happened. The question is: is it natural or is it man made? 2) in this case here: you want to close a case without having seen any actual data? -
Dikran Marsupial at 22:37 PM on 17 June 2011CO2 has a short residence time
Eric (skeptic) The constant airborne fraction (45%) is essentially due to the fact that anthropogenic emissions are rising approximately exponentially. This result is easily reproduced by a one-box model of the carbon cycle (I am working on an article on this topic). That means if anthropogenic emissions are cut then the airborne fraction will be no longer constant. IIRC a simple one-box model of the carbon cycle gives an adjustment of about 74 years once you take that into account. There is nothing spurious about the 500+ year time scale. The carbon cycle can only be approximated very roughly by simple models such as yours. There are other reasonably well understood physical reasons (e.g. slow transfer of carbon between the surface and deep ocean) that make the simple model give unrealistically low estimates. If you want to look more deeply into these issues, I can recommend David Archer's primer on the carbon cycle, reviewed here However, your calculation is still much more accurate that Essenhigh's, as you obviously understand the difference between residence time and adjustment time. Also, CO2 levels falling about halfway back to pre-indiustrial levels in about 50 years is pretty much the mainstream view
(posted by Daniel earlier in the thread)
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jatufin at 22:33 PM on 17 June 2011Phil Jones - Warming Since 1995 is now Statistically Significant
How about: "Of course yes! What would you except from so short period? We use much longer time frames -- 30 years or so -- to be sure a trend we see is real. Still... Even the warming we've witnessed during the last 15 years only, it is almost there. Only haircut, two or three percentage points, short from being statistically significant." -
Rob Painting at 22:30 PM on 17 June 2011CO2 Currently Rising Faster Than The PETM Extinction Event
Tony - they are the Eocene hyperthermals (although I don't see where you get 44 mya in the figures above). They seem to be driven by orbital changes . See the hyper-link above for Dickens 2009 and also: Sexton 2011 Galeotti 2010 -
Eric (skeptic) at 22:28 PM on 17 June 2011CO2 has a short residence time
I noticed this thread was referenced in the new "CO2 rising faster than PETM" thread. I wrote a spreadsheet that I just made publicly accessible (forgot to do that above). I used the published figures for CO2 added the atmosphere 1750-2008. Then I assumed an expoential decay. Nature absorbs about 1/2 of our added amount each year and since that is a consistent result year after year, an exponential decay back to preindustrial is a reasonable assumption. Based on the rise to 2008, the lambda is 4.25 (I also assume lambda is constant when it seems likely to rise with CO2 concentration). The half life of CO2 (time to return 1/2 way back to preindustrial) is 48 years. An argument that the "lifetime" of CO2 is 500 years or more is ill-defined and somewhat spurious. Yes, it would take that long to get all the way back to preindustrial, but getting half way back in 50 years is more meaningful. The document link is here: http://public.iwork.com/document/?a=p1415598010&d=CO2growth.numbers -
Robert Murphy at 22:26 PM on 17 June 2011The greenhouse effect is real: here's why
MoreCarbon, you wrote the same exact post here Is there a reason you are posting the same thing on multiple threads? -
MoreCarbonOK at 22:16 PM on 17 June 2011The greenhouse effect is real: here's why
case closed? From the results at randomly chosen weather stations it would appear that there is no warming caused by a green house effect: For the record and for those interested: http://www.letterdash.com/HenryP/henrys-pool-table-on-global-warming (-Snip-)Response:[DB] If you've made a point before and it's also on-topic here, then provide a link to that point. We're more than capable of following links. The rest of your comment here is nothing more than pointlessly arguing cherry-pick fallacies (i.e., since cherries are red apples can not also be red).
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Tony Noerpel at 21:55 PM on 17 June 2011CO2 Currently Rising Faster Than The PETM Extinction Event
There is another temperature spike in the middle of the Eocene around 44 Mya. Has this been studied as much as the PETM? Any information on it? thanks Tony -
Kevin C at 21:23 PM on 17 June 2011Who's your expert? The difference between peer review and rhetoric
Good discussion - I like the term 'gate keeper' (I've tended to use 'junk filter') and especially 'peer response'. CBDunkerson@13:Thus, passing peer-review is USUALLY enough to identify something as valid science, but there are occasional mistakes and a few cases of outright fraud... but those quickly fall by the wayside while valid papers are referenced and built upon in further research.
Ah, now I think you've just picked out something particularly important. There are two separate questions we can ask about a paper: 1. Is it valid science? 2. Is it right? A paper may be neither, it may be valid science but wrong, or it may be valid science and right. (I suppose you can also have a paper that is right but not valid science, if it is right by chance.) The journal peer review process should certainly pick out invalid science, but will also pick out some egrariously wrong science as well. As for what gets published, I guess one of the key questions in determining to what extent we can rely on a paper simply because it is peer reviewed is what proportion of peer reviewed papers are valid science but wrong. I would like to suggest that the proportion is significant, even in real jornals and in articles from reputable authors. One piece of evidence for this lies in the fact that many papers cite at least one previous work in order to disagree with it. Does this invalidate science? No, one way science progresses through a conversation between papers in which the errors are gradually weeded out. But does mean that being peer-reviewed is not a sufficient reason on its own to trust a paper. That's where Adelady's peer-response metric fits in. -
Eric the Red at 21:18 PM on 17 June 2011Who's your expert? The difference between peer review and rhetoric
Overall, peer-review is a good process to evaluate the merits of a paper. However, it should not be idolized as a grand metric differentiating between acceptable and non-acceptable work. Peer-review is just that, a review by your peers. Most times "correct" papers get published, other times not. After all, if your peers are doing similar work, they may see similar results. Sometimes articles appear in scientific journals or magazines which contain preliminary results which the researcher deems significant enough to portray to others. Oftentimes, this will lead to a research report submitted at a later date. That does not automatic relegate the original article to an invalid state, but rather has not gone through the peer-review process to check for potential errors. Since peer-review is a human process, it is governered by human limitations. Consequently, the reputation(s) of the author(s) does influence the process. The biases of the reviewers can also play a role. Papers are occassional pased through to fill session in conferences, and later published with the proceedings. Having taken part in peer-review from both sides, I can see many of the advantages and disadvantages, and that the advantages far outweigh the disadvantages. I will reiterate that it is a good process to determine the merits of research, but not the endall barometer. -
BillyJoe at 21:06 PM on 17 June 2011Who's your expert? The difference between peer review and rhetoric
DB,thanks for the links. -
CBDunkerson at 21:02 PM on 17 June 2011Who's your expert? The difference between peer review and rhetoric
Generally speaking, only peer-reviewed papers are cited in the scientific literature. Thus, IMO the primary way that peer-review impacts the progress of science is by determining which materials make it into the ongoing 'discussion' and which do not. That said, if utter garbage is let through a fake 'peer-review' process (E&E anyone?) the scientific community will just reject it in the wider 'peer-review' that is ongoing research. Thus, passing peer-review is USUALLY enough to identify something as valid science, but there are occasional mistakes and a few cases of outright fraud... but those quickly fall by the wayside while valid papers are referenced and built upon in further research. -
Eric the Red at 20:53 PM on 17 June 2011Forecast: Permanently Hotter Summers in 20-60 years
Yes, the net effect over time of the PDO is zero. However, that does not mean that the PDO has not affected the observed weather during the past century. What you call noise, has been observed as an oscillation with an amplitude of about 0.4C - that is a lot of noise. Removing this "noise" from the temperature observations results in a very linear temperature increase of 0.6C / century since 1880 - basically the entire thermometer data record. While that does not prove that the PDO is responsible for the noise, there is much understanding to explain the observed effect. Is it optimistic or simply realistic to attempt to identify and correlate all the factors affecting our climate? The climate models are constantly being redefined to incorporate new information. If the PDO was the cause of the cooling in the mid 20th century, and the cause of the recent temperature observations, then it should be incorporated into the models. It will change the end result if the observed warming was partially due to the PDO in one of two ways: either the temperature time lag is longer than proposed, or the climate sensitivity is too high.Moderator Response: It is past time to move this discussion of PDO to the thread "It’s Pacific Decadal Oscillation." Further comments on that topic on this thread will be deleted. -
Robert Murphy at 20:36 PM on 17 June 2011Hansen's 1988 prediction was wrong
Doesn't the link from RealClimate show the projected CO2 for 2010 was 392ppmv? And wasn't the actual level in 2010 389ppmv? It's a minor point, but it looks like you have that reversed on your chart. -
michael sweet at 19:56 PM on 17 June 2011Speaking science to climate policy
Correction: the Bush Administration actually removed "to understand and defend our home planet." from the NASA mission statement, not "protect" the home planet. -
Dikran Marsupial at 19:54 PM on 17 June 2011Phil Jones - Warming Since 1995 is now Statistically Significant
Henry@Dikran "I don't need a comment from you." s/need/want/ If you can't take on board constructive criticism, your analysis will continue to be meaningless. Not engaging with technical criticism of ones scientific position is denialism. Your perogative of course. -
MoreCarbonOK at 19:44 PM on 17 June 2011Phil Jones - Warming Since 1995 is now Statistically Significant
Henry@TomCurtis The average temperatures for the daily mean, maxima and minima and other weather data for Brisbane are given at the end of each month of the year from 1976 to 2011 at this site: http://www.tutiempo.net/en/Climate/Brisbane_Airport_M_O/945780.htm For the record and for those interested: As it stands at the moment (on my pool table), http://www.letterdash.com/HenryP/henrys-pool-table-on-global-warming it appears that maxima, means and minima have risen in a ratio of about 4:2:1 over the past 4 decades. For the time being, my conclusion is therefore that the warming is natural because it is the maxima that pushed up the average temps and minima. I think if I could get these results, anyone else should be able to get the same, as long as they play the game according to the rules: i.e. 1) randomly 2) balanced, ::::NH versus SH Namely the funny thing is that I observed now is that the warming is not at all the same in the SH (where I started playing) and the NH. Why that is I don’t know> perhaps it could be because there is much less landmass in the SH? But why would that make a difference? Anyway, whatever the reasons, I now have to carefully look at my table again, to balance it, i.e the same amount of stations NH and SH + approx. same NH latitudes and SH latitudes. Not an easy task for one and only person….with only a limited amount of hobby time and that is: yours truthfully Henry Henry@Dikran I don't need a comment from you.Response:[DB] "Henry@Dikran
I don't need a comment from you."If you do not wish others to respond to comments you post here then don't post here. Either way, try to exercise more civility. Politeness goes a long way towards establishing credibility.
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Dan Olner at 19:33 PM on 17 June 2011Who's your expert? The difference between peer review and rhetoric
"I'm wary of idolising peer-review as the metric of truth." Agreed: this article asserts, it doesn't explain. To anyone who'd never heard of peer-review, what would they think? Sounds like appeal to authority (your peers, in fact!) What I'd like to read: an explanation of how the peer review process manages to (over time) produce a good approximation to knowledge. On the face of it, there's no reason to suspect it would: peer review has to exist in a system that incentivises those peers to *want* to tear down any mistakes they find. It's quite possible to imagine `peer review' that does nothing of the sort - and indeed journals exist where that's the case. So what distinguishes good from bad peer review? Is it actually anything to do with `peer review' itself, or is it to do with the structure of the disciplines they're embedded in? Or what? -
michael sweet at 19:24 PM on 17 June 2011Speaking science to climate policy
Ken, I suggest you read the linked paper. Hansen has been calling for a satelite to measure aerosol contributions since at least 1990 and estimates in the paper I linked at 7 that such a mission would cost only $100,000,000. For various political reasons it has never been launched. (The Bush adminsitration removed "protect the home planet" from the NASA mission statement, but Clinton did not launch it either). Tom's graph indicates that your description of a lag between when the West (partially) cleaned up their aerosols and when China started emitting large amounts correlated with the temperature rise you described. Perhaps if you read the background you would see that this is a coherent narative. This is a critical issue since if in fact aerosols have hidden 1C of warming we are in for a big shock when China cleans up its act, as it eventually must. The ocean's thermal inertia holds back the temperature over the ocean and nearby land. A quick type of "ocean thermal inertia" in the search function yields Has Earth warmed as much as expected? which describes how the ocean holds back the temperature of the Earth in the first section labeled "Thermal Inertia". The search has a large number of additional hits. Your argument that "Ocean thermal inertia can only redistribute heat" is simply incorrect. You have been on this site long enough to have read this material, what are you trying to show with such a naive argument? -
bartverheggen at 19:00 PM on 17 June 2011Speaking science to climate policy
Tropospheric aerosols have a lifetime of several days or weeks (dependent on their size). In sharp contrast to the lifetime of greenhouse gases, ranging from 12 years (methane), via nitrous oxide (120 years) to CO2 (100's to 10(0),000's of years). Stratospheric aerosols (e.g. as a consequence of large Tropical volcanic eruptions, but also in-situ formation) have a lifetime of a couple of years. See also this background on atmospheric aerosols that I wrote on my blog. -
michael sweet at 18:52 PM on 17 June 2011Websites for Watching the Arctic Sea Ice Melt
DB: Neven's name is spelled wrong twice in the last paragraph, can you change to Neven from Nevin? Please delete this post. -
Bern at 18:35 PM on 17 June 2011Who's your expert? The difference between peer review and rhetoric
Kevin C: I think adelady has it right - peer review is a gate-keeping exercise, that is less about establishing whether a paper is *correct*, as establishing whether it is obviously *incorrect* - in which case, it doesn't get published until the obvious errors are fixed. Less obvious errors will usually end up with comments, letters, or further papers being published to point them out - sometimes by the original authors. As I understand it, though, it takes more than errors to prompt an actual retraction. I've been responding to some comments on the cross-post of this at ClimateSpectator. I've seen the "it's water vapour" one again, and "Phil Jones conspired to block critics' papers", and "it's not warming", and "sea levels aren't rising", and "CO2 is plant food". On a related thread on BusinessSpectator, I even had someone tell me that a 1.5% annual increase in evaporation & precipitation was a slow-down of the hydrological cycle... (I had to read that one three times to check I hadn't misunderstood!) -
MartinS at 18:27 PM on 17 June 2011CO2 Currently Rising Faster Than The PETM Extinction Event
@idunno: CH4 reacts rapidly to CO2 (oxidation with OH). Possibly the oxidation happend already in the sea water or later in the atmosphere (CH4 has a short lifetime compared to CO2). The CH4/CO2 differentation is important to explain the negative carbon isotope excurison. CH4 has an extremly negative deltaC13 ratio of about -50 per mille, therefore you need less CH4 than CO2 to explain the excursion. -
scaddenp at 18:24 PM on 17 June 2011CO2 Currently Rising Faster Than The PETM Extinction Event
okatiniko - different carbon characteristics. d13C ratio is way depressed for PETM. -
scaddenp at 18:19 PM on 17 June 2011Who's your expert? The difference between peer review and rhetoric
Well peer-review has to be the starting point. It doesnt make it right, but compared to a blog post? The most important bit though is that does create an audit trial. If the community likes it, builds on it, then it gets cited. If something doesnt gel with current theory, then you can follow the trail back and re-examine the paper and its methods. By contrast, if its not peer reviewed, and not in a field where you have enough domain knowledge to evaluate yourself, then you are always asking what would real peer's make of it. -
adelady at 18:19 PM on 17 June 2011Who's your expert? The difference between peer review and rhetoric
Kevin, I see peer review as a gate-keeping exercise. The term I think you're looking for is "peer response". After all a bare handful of people, highly qualified though they may be, is all that's required for peer review. Good peer response - which usually means lots of citations as well as further work on the topic - is what leads to scientific consensus. A bad peer response, or if the paper in question is simply ignored and never cited, does not mean that the initial gate-keeping exercise failed (usually). It just means that more people, perhaps more highly qualified, can find errors of fact or reasoning in a paper which looked OK to start with. -
les at 18:12 PM on 17 June 2011Who's your expert? The difference between peer review and rhetoric
In a way Kevin C is right and wrong in any case. If you look at the background history of the vast majority of quotidian papers published, there are many levels of peer-reviews. On average the academics in most universities will have been recruited, will apply for grants, will present material at seminars, conferences and workshops, will have discussed results with collaborators and students and so on. Often a journal editor will take a pro-active role in the paper as well as the reviewers... The implicit objective of all this is not to get consensus but robustness. IMHO problems come in two places. First, with results which are not controversial; as people tend not to question them as much. With controversial results, folks tend to look for higher levels of robust argumentation. Second with publishers who are outside the establishment... not because mavericks are bad, not because The Establishment should be preserved or what ever - but because they are not subject to all the other peer-review events that occur way before a paper is actually submitted. Sure, it works sometimes - but that can be a selection bias; it really really doesn't work 99% of the time - but then, very few people get to see the vast swathes of rubbish that is rejected from journals except for bits here and there which end up as blogs or in 4th rate publications. -
idunno at 17:42 PM on 17 June 2011CO2 Currently Rising Faster Than The PETM Extinction Event
Hi Rob, An excellent article, but I would criticise the repeated use of "CO2" in the first few paragraphs. As you go on to state later on, it is very possible/quite probable that the PETM was caused by methane (CH4), not CO2. Looking at the records of atmospheric composition, it would seem that CO2 has tended to undulate up and down, whereas the level of CH4 looks like a saw blade, with sudden spikes which then gradually fall back towards normal. I would speculate that this is an indication that, on many separate occasions, events such as the Storegga landslide of c.6100 BCE have occured; i.e. a submerged gasfield has collapsed and vented directly into the atmosphere. Methane in the atmosphere acting as a greenhouse gas, this should cause further warming, destabilising the methane clathrate layer, and causing further warming from this. Furthermore, the methane clathrate layer is solid; as it decomposes, it will liquefy, and possibly allow the uncapping of further gaseous deposits of methane. Unless we can find evidence that the dinosaur car use was about 10% of current human car use, I'm not sure we have any other good explanation of the CO2 spike at the PETM. In conclusion, I stongly suspect that the CO2 spike is actually decayed methane. I should round off though, by saying that this is largely based on a layman's (my own) imperfect understanding. This may well be quite wrong; but if it is right then your first several paragraphs make too many references to CO2, IMO. -
Kevin C at 17:19 PM on 17 June 2011Who's your expert? The difference between peer review and rhetoric
I'm wary of idolising peer-review as the metric of truth. After all, many peer-reviewed papers are wrong. The papers which open up new areas of research are frequently both ground-breaking and largely wrong. And taking this approach is just setting ourselves up for a fall whenever a wrong paper, especially a paper which is wrong on climate, makes it into the peer-reviewed literature. The real test of a theory is its reception in the wider community over years and decades. I would like to broaden the term 'peer-review' to mean this, but it is not the common usage. 'Scientific consensus' fills roughly the right role, but creates problems for the public who see opposing talking heads in the media and conclude that no consensus (in the common rather than scientific usage) exists. There are interesting developments in evolutionary psychology (beware - not consensus) on why individual and small group reasoning is necessarily suspect, with the implication that science must by necessity rely on something like 'consensus'. See: http://sites.google.com/site/hugomercier/theargumentativetheoryofreasoning http://www.dan.sperber.fr/wp-content/uploads/2009/10/MercierSperberWhydohumansreason.pdf -
Dikran Marsupial at 17:14 PM on 17 June 2011Phil Jones - Warming Since 1995 is now Statistically Significant
Charlie A Yes, I expect it is, in the sense that the slope of the OLS trend is statistically significant. There may be other, perhaps better, tests of statistical significance where perhaps it isn't. There is scope for arguing that the headline is wrong, but if you are going to be as critical of Jones as you possibly can, you need to ask yourself why you are not being even more critical of Linzen and Motl, whos errors have been far more egregious. The point is that statistical tests over such a short time scale have little statistical power, and hence the probability of a false-negative (not being able to reject the null hypothesis when it is false) is high, so it doesn't mean much if the slope is not significant (even without the cherry picking). It is also worth noting that Prof. Jones is not making a big deal out of the trend going from insignificant to significant. He is still saying that longer timescale trends (e.g. 30 years) are what we need to look at. -
adelady at 17:14 PM on 17 June 2011Infographic: 97 out of 100 climate experts think humans are causing global warming
"... the survey confirms my experiences: meteorologists are quite resistant to the idea of AGW. I can't explain why this is so. " Two reasons I suspect. Firstly, meteorology training doesn't have the same emphasis on basic physics as climate researchers do. And this exacerbates the main reason ... Secondly, meteorologists know very well that weather can't be predicted more than a few days out. Because it's just not possible to enter, let alone compute, all the possibly relevant information hour by hour, day by day. Most meteorologists work in a framework limited, almost entirely, by initial conditions. They have to abandon and invert that thinking to deal with climate, which is all about boundaries and limits - regardless of initial conditions. And they need to pick up on some physics and more statistics into the bargain. Most could do it. The real problem arises with those who don't try and don't want to try. -
Rob Painting at 17:04 PM on 17 June 2011CO2 Currently Rising Faster Than The PETM Extinction Event
The glacial-interglacial shifts are caused by Milankovitch Cycles which isn't the case with the PETM. Nor were there any major ice sheets back then. What exactly are you proposing? -
okatiniko at 15:58 PM on 17 June 2011Our effect on the earth is real: how we’re geo-engineering the planet
". She was referring to permaculture when she pointed out that we have all the atoms/molecules we will ever have.' That's an important point. The real wealth is not the number of atoms, but the way they can be used. What we need is concentrated sources of energy, in other words, negentropy. Concentrated minerals and fossil fuels are huge sources of negentropy. But they are finite, and decreasing. The only renewable source of negentropy on the Earth is solar radiation, converted in chemical negentropy by natural photosynthesis. This was the "natural" source of negentropy used by traditional civilizations. Ours is quite different - and probably with a small life expectancy given the rate at which it burns its sources of negentropy. -
PT_Goodman at 15:56 PM on 17 June 2011Infographic: 97 out of 100 climate experts think humans are causing global warming
Tom Curtis @23 I share Harry Seaward's concern over what boils down to a climate relevant sample size of 79. I discuss AGW with deniers all the time, and they will simply dismiss me if I tell them that the sample size from which the 97% figure was derived was a mere 79 people. I'm getting up in years, and have no children. Maybe I should be content with letting inmates now running the asylum roll the dice--after all, it is only them and their descendants who will suffer the consequences. In at least one other respect, the survey confirms my experiences: meteorologists are quite resistant to the idea of AGW. I can't explain why this is so. -
okatiniko at 15:29 PM on 17 June 2011CO2 Currently Rising Faster Than The PETM Extinction Event
when you say "The rapid pulse of PETM CO2 followed by rapid warming (figure 2e) indicates high climate sensitivity. ", what is the delay between CO2 and temperature ? I thought that more recent glacial-interglacial transitions showed that CO2 lagged the temperature variations. Can it not be explained the other way round? -
sgmuller at 15:19 PM on 17 June 2011Who's your expert? The difference between peer review and rhetoric
I'd suspect its just economic rationalism. Maintaining and monitoring a ground based weather station in remote country is labour intensive work. -
Paul Magnus at 15:02 PM on 17 June 2011Who's your expert? The difference between peer review and rhetoric
Hear hear. It's time jokers get taken for what they are. -
Stevo at 14:48 PM on 17 June 2011Who's your expert? The difference between peer review and rhetoric
Comments to this article on The Conversation are going quite well at the moment. Those opposed to the peer review process are not aquitting themselves well. Makes for a pleasant change. -
Tom Curtis at 14:42 PM on 17 June 2011Who's your expert? The difference between peer review and rhetoric
One nice thing about the peer review system is that in, in order to be published you just have to convince three to five people who have the knowledge and skills to assess your argument that your argument is worth considering. You don't have to convince them that you are right; only that the case you make is cogent enough to be worth further thought. A second nice thing is that if you can't convince the first group, you can always try again at another journal. Or improve your argument and/or evidence and try again at the same journal. That means that if your argument really is worth considering, it is highly unlikely to not be published. Conversely, if you can't get your paper through the peer review system, that means from a wide selection of people well informed enough, and skilled enough to understand your argument, you can't even get a few to agree that your argument is even worth considering. Worth thinking about. -
Paul Magnus at 14:40 PM on 17 June 2011Who's your expert? The difference between peer review and rhetoric
Mags like Forbes need an ass kicking... http://blogs.forbes.com/patrickmichaels/2011/06/16/peer-review-and-pal-review-in-climate-science/ -
BillyJoe at 14:22 PM on 17 June 2011Who's your expert? The difference between peer review and rhetoric
Sorry, this is off-topic, but... Can anyone link me to an article that discusses why ground based temperature measuring stations have been disappearing. (-Snip-) -
Patrick 027 at 13:42 PM on 17 June 2011The Planetary Greenhouse Engine Revisited
Re 11 Michele - part of the problem, I think, is that you are using imprecise concepts, or at least imprecise language, which may lead you to confusion. First, the emission from the surface is not changed (in any simple direct way) by atmospheric radiation. What is changed is the amount of that radiation which reaches space, and the amount and distribution of absorption of that radiation by the atmosphere, and the amount of radiation from the atmosphere absorbed by the surface. Your first equation, εTs^4 + Tt^4 = Te^4, is simply incorrect. Even as an extreme simplication (of a grey gas isothermal atmosphere at temperature Tt overlaying a blackbody surface), the equation should be εTs^4 + (1-ε)*Tt^4 = Te^4 - but then the meaning of ε is 1 - atmospheric absorptivity, which is equal to atmospheric emissivity (the effective value over all directions, which I think can be used for an isothermal atmosphere). Really it would make more sense to use an ε for the atmosphere, and then you get (1-ε)*Ts^4 + ε*Tt^4 = Te^4. This is correct for this very simple case. But the atmosphere is not a single isothermal layer. It is helpful to consider emission weighting functions. You described the tropopause and mesopause as if they are surfaces that collect heat from the rest of the atmosphere and radiate to space. This is only partially true in a sense. The colder **layers** and surfaces (applicable to low-level inversions) will emit less than they absorb from warmer **layers** and surfaces. But depending on optical properties, the entire atmosphere can be emmitting radiation to space; it happens that, assuming well-mixed gases and setting aside pressure and doppler broadennning and temperature-dependent line strength, the fraction of radiation emitted upward that escapes to space increases going upward, toward 100 % at the top of the atmosphere. Rather than going over the details of fluxes that you find at any level, consider emission weighting functions (EWF for short here). For a radiation of a given direction, polarization, and frequency, the distribution of where that radiation is absorbed is equal to the EWF for radiation of the same type coming back from that direction at the same point. EWF is a density distribution over space, and taking the product of that with the Planck function at each location and integrating over volume (well, over a line if there's no scattering), gives the intensity of the radiation coming from a given direction; the temperature for which the Planck function equals this value is the brightness temperature of that radiation, and if it weren't for the nonlinearity of the Planck function, it would be equal to the EWF-weighted average temperature; if not for the (potential for) nonlinearity in both the Planck function and the temperature profile, it would be the temperature at the centroid of the EWF. Hence the brightness temperature may be equal to the temperature somewhere within the EWF (this must be true if the EWF and temperature vary continuously over space), and the location where this temperature occurs may be thought of as an effective emitting level (note that this varies with direction, so for the whole flux you have to have a weighted average of EWF's for each direction, etc.) The effective emitting level of radiation reaching space won't necessarily or generally be at the tropopause - even if it were, this is only a representative level - radiation is being emitted to space from a whole layer, potentially extending down to the surface. Regarding why parts of the atmosphere can be colder than Te, consider a case of pure radiative equilibrium with a grey gas. For a sufficiently thin layer at the top of the atmosphere (TOA), the emissivity and absorptivity of that layer can be approximated as zero in their effect on the flux from below, but the layer's temperature is still determined by those vary small quantities. It absorbs some fraction, a, of radiation from below, which must be approximately sigma*Te^4, and in radiative equilibrium, assuming no other heat sources, it must emit a*sigma*Ttoa^4 (Ttoa is the temperature at TOA) both upward and downward. Thus Ttoa^4 must be half of Te^4 (note that if space were radiating downward as if a blackbody at Te^4, then Ttoa = Te. But space's brightness temperature can generally be approximated as zero). This is the temperature of the skin layer. Temperature generally varies continuously through an atmosphere so T must drop below Te at some point below. For atmospheric absorption which is not grey, the formula for Ttoa will be different but at least for well-mixed greenhouse gases, it will still be less than Te. With solar heating, the equilibrium T in the upper atmosphere may be higher than Te, but if solar heating is not sufficient to prevent it, layers colder than Te may still be found as well. The ozone layer is responsible for the temperature maximum at the stratopause, and absorption of higher-frequency solar radiation is responsible for the thermosphere, but in between those regions and between the upper stratosphere and the lower troposphere, T can be below Te because their is sufficient transparency above such that not enough radiation is absorbed from above to prevent it. Convection within the troposphere doesn't all go to the tropopause; going higher up, the convective heat flux from the surface declines. This balances a net radiant cooling (including any direct solar heating of the air). It is theoretically possible to have a troposphere in which some layers have no net radiant cooling, in which the convective heat flux, on average in equilibrium, would be constant. -
jyyh at 12:39 PM on 17 June 2011CO2 Currently Rising Faster Than The PETM Extinction Event
PETM "explained" at http://erimaassa.blogspot.com/2011/06/already-done.html -
Rob Painting at 12:00 PM on 17 June 2011CO2 Currently Rising Faster Than The PETM Extinction Event
Jerryd- a hyper-link to the full Dickens focus article is provided under Figure 1. Are you he? -
jerryd at 11:32 AM on 17 June 2011CO2 Currently Rising Faster Than The PETM Extinction Event
Hej, I guess my first thought is ... wow ... it's great to see people interested in the PETM. It's a truly wonderful topic of current scientific interest, in part because we still cannot explain the event. How can Earth's surface warm and receive massive amounts of carbon in a geological instant 55 million years ago? The event was discovered 20 years ago; a wide array of data across the event shows basic signatures predicted by climate models for our future; it defies a satisfactory explanation within any accepted model for global climate or carbon cycling. Welcome to a really interesting puzzle! Thought might be good to pass along the text to Figure 1 (and the background to the PETM): http://www.cseg.ca/publications/recorder/2009/02feb.cfm Jerry
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