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CBDunkerson at 21:23 PM on 30 June 2010September 2010 Arctic Ice Extent Handicapping Via ARCUS
There is a very good new article on Cryosat-2 showing some of the first data released here. The Arctic scan included in the article shows situations where previous instrumentation (e.g. PIPS) would have reported a large area of thick ice for what was really just a few large chunks. They're still calibrating data (after moving the satellite into a new orbit), but expect to start releasing results in a few months. Thus they should be able to tell us what the minimum ice volume for this year was, but it may be a couple of months after the event. -
CBDunkerson at 21:14 PM on 30 June 2010What is Global Warming and the Greenhouse Effect?
RSVP #15, so everything in the article above is true... but you are arguing that the AMOUNT of warming may be negligible. Which seems like arguing for the sake of arguing since the article states that this very issue, how much warming is likely to occur, will be covered in a subsequent installment. So leave that aside for when it's actually considered and take this article for what it is... a simple explanation of greenhouse warming which is every bit as "accurate, absolute, and true" as Newton's third law of motion. A point which only need be made because 'skeptics' jump up to object whenever it is... falsely suggesting that there is some doubt on the issue. -
Baa Humbug at 20:46 PM on 30 June 2010What causes the tropospheric hot spot?
Thnx David Yes I also must agree that the results are a little unsatisfying. From the links in the original article, Titchner et al says (for instance) "our analysis using realistic validation experiments is unable to discount or confirm the presence of a tropical tropospheric lapse rate discrepancy between the radiosonde observations and climate model expectations". And Sherwood says "the agreement would improve if one were to remove the deep tropical stations whose behavior is inconsistent with the rest of the network. This reinforces similar previous findings of consistent trends (Fu et al. 2004; Mears and Wentz 2005; Sherwood et al. 2005; Vinnikov et al. 2006) but remains unsatisfying until errors are further reduced". Regarding the hot spot being a "signature" of GHG warming, I must respectfully disagree. It's not just the IPCC presenting a chart which clearly shows the distinctive signature of GHG warming (chart C in the article), four other organizations show very similar signature. (I hope I can do the image thing correctly)
Zonally-averaged distributions of predicted temperature change in ºK at CO2 doubling (2xCO2 – control), as a function of latitude and pressure level, for four general-circulation models (Lee et al., 2007).
Eyeballing each of these, one would be excused for concluding a tropospheric warming of up to 3 times that of the surface.
The IPCC quote you provided is unequivocal IMHO, where it states, "The combination of a warming troposphere and a cooling stratosphere has likely led to an increase in the height of the tropopause and model-data comparisons show that greenhouse gases and stratospheric ozone changes are likely largely responsible".
So if GHG's are largely responsible, then GHG's are the main cause of the distinct hot spot, which as the 6 graph chart shows in C and F, is much more powerful than other forcings, man made or natural (a,b,d,e)
So I guess where I am at this moment is that a number of organizations including the IPCC have taken the trouble to distinguish GHG influence on the troposphere at the tropics. Why they chose to do that is theirs to answer.
I await eagerly, some definitive papers on the unsatisfying troposphere t trends.
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RSVP at 20:27 PM on 30 June 2010What is Global Warming and the Greenhouse Effect?
doug_bostrom, werafa, et all "For every action, there is an equal and opposite reaction." That was Newton talking about inelastic collisions between moving bodies. This is accurate, absolute, and true. How does this play out when one mass is that of the Earth, and another, a small rock landing on say a hard cement patio? Does the Earth "react"? Not a whole lot. The issue is not whether CO2 aborbs or emits IR. The issue is whether the amount of CO2 is making any measurable difference in climate change. If my assertions sound confusing, it is only because the dynamics are complex. For instance, water vapor is transparent and reflects light depending on temperature and pressure. This means that modeling the effects of just water vapor on its own is complex and non linear. -
David Grocott at 19:25 PM on 30 June 2010What causes the tropospheric hot spot?
Baa Humbug @ #53 No problem. You say "Between satellites and radisondes this amount of warming should have been detected. It hasn't been." That is your view, and I can only refer you back to the article above and John's original article addressing Nova's claims. John points out that the amount of expected warming (or near to it) has been detected by weather balloons (Titchner 2009, Sherwood 2008, Haimberger 2008), wind shear measurements (Allen 2008), and the UWA satellite data. And as Prof. John Christy points out, the discrepancy between the UAH satellite observations and the models is most likely a result of measurement uncertainty. Regarding the 3 possible options for explaining the existing uncertainty, the IPCC does argue for one:Since the TAR, further evidence has accumulated that there has been a significant anthropogenic influence on free atmosphere temperature since widespread measurements became available from radiosondes in the late 1950s. The influence of greenhouse gases on tropospheric temperatures has been detected, as has the influence of stratospheric ozone depletion on stratospheric temperatures. The combination of a warming troposphere and a cooling stratosphere has likely led to an increase in the height of the tropopause and model-data comparisons show that greenhouse gases and stratospheric ozone changes are likely largely responsible (Figure 9.14). Whereas, on monthly and annual time scales, variations of temperature in the tropics at the surface are amplified aloft in both the MMD simulations and observations by consistent amounts, on longer time scales, simulations of differential tropical warming rates between the surface and the free atmosphere are inconsistent with some observational records. One possible explanation for the discrepancies on multi-annual but not shorter time scales is that amplification effects are controlled by different physical mechanisms, but a more probable explanation is that some observational records are contaminated by errors that affect their long-term trends.
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch9s9-4-5.html As you can see the IPCC raise the possibility that the models are incomplete (option 2), but suggests it is more likely that the discrepancies are a result of errors in the observational record (option 3). I'm inclined to agree with John when he says "Looking at all this evidence, the conclusion is, well, a little unsatisfying". However, if you take the view that the hot spot is absent, and you don't agree with the IPCC that its perceived absence is a result of measurement uncertainty (or possibly problems with the models), then you must take the view that the temperature record is unreliable. Something Roy Spencer (for one) disagrees with. When making judgements (which you sometimes must) it's important to look at the whole picture, and make the most reasoned call. In my view the most obvious call is that the contradictory evidence is a result of measurement uncertainty; any other judgements would involve larger leaps of logic. Regarding your final point:Also, as much as I appreciate the charts you have posted, the AR4 makes it clear that the sun has had negligable affect on climate in the 2nd half of the 20thC, therefore, if a hot spot was to be detected, (along with a cooling stratosphere) it can only be a response to CO2 forcing, no?
Correct - if you first accept the IPCC's assertion that human activity is largely responsible for the rise in global temperatures - which I think is where all this confusion about the hot spot being a signature of AGW comes in. The IPCC, as you state, makes clear that anthropogenic forcings are the primary contemporary climate forcing. Therefore, if a hot spot is detected then it would be evidence of warming, which by the IPCC's definition must have been caused by human activity. Finding the hot spot doesn't prove that humans have caused global warming, in fact it doesn't prove anything, but it does show that the models are correct in what they anticipate the effects of any warming to be, and in the process strengthen the case that warming is occuring. The fact that the troposphere is warming and the stratosphere is cooling (as shown by observational data) does provide evidence that it is humans that are causing the current warming, as opposed to the sun's activities. -
werafa at 18:25 PM on 30 June 2010What is Global Warming and the Greenhouse Effect?
Please also remember who we wish to inform and influence. Scientists regularly fail to engage members of the public precisely because they insist on absolute precision, but loose accuracy and effect. This post, for all its generalisations, explains a concept in a way that my mum could understand. That is vital -
John Chapman at 18:24 PM on 30 June 2010On the reliability of the U.S. Surface Temperature Record
In cold climates those reverse-cyle ACs actually blow out cold air, so maybe that's why the poor-sited readings are often lower? -
werafa at 18:19 PM on 30 June 2010What is Global Warming and the Greenhouse Effect?
Carbon dioxide is part of the greenhouse effect, and this does keep the globe warm. Without the greenhouse effect, life would probably not exist. does increasing the amount of carbon dioxide enhance the warming effect? The evidence says yes it does, and this is the basis of the Global Warming theory. Note: It is not yet (and probably never will be) possible to prove this with absolute statistical certainty, but would you go on 100 plane flights if you only have a 95% chance of surviving each flight? -
John Chapman at 18:02 PM on 30 June 2010Ocean acidification
At a talk last night David Archibald finished by showing a picture of some coral and CO2 bubbling past. Well they were bubbles, but he said it was CO2 and the coral looked dead to me and he said there were fish swimming around though I couldn't see any in the photo. What do you make of his claim that coral is resililent to acidification? -
JMurphy at 17:50 PM on 30 June 2010Hockey stick is broken
doug_bostrom wrote : "Sorry, I'm not biting. Anybody else up for a pointless argument?" I would direct marty to NOAA Paleoclimatology (hope they're not considered biased and part of the big conspiracy), where he can check out data from boreholes, pollen, insects, etc. But, marty, why do you think bristlecone pine data is 'misleading' ? -
Doug Bostrom at 17:40 PM on 30 June 2010Sea level rise is exaggerated
Ad hominem, Daniel? Yes, some things concern attributes of individual persons, specifically in this case what they know and don't know. Are you a geologist with an advanced degree specialized in paleochronology, Daniel? Have you spent a significant portion of your life learning how to tease dating information out of stratigraphic sequences? If you can honestly answer "yes" then my comparison of your abilities with regard to paleochronologies with those of Donnelly is less relevant. If you can only answer "no" then your assertion that Donnnelly's paper is "pure junk" is notably arrogant and makes your lack of qualifications a matter of complete relevance. If you answer "no" you are an amateur without a professional record casting rather nasty aspersions on the work of a professional with an extensive research track record in the subject you purport to be able to judge. There's entirely too much of this sort of thing going around, it's debasing to everybody concerned. You seem upset that you're not free to make whatever remarks you please here. I suggest that you've developed some poor habits by frequenting places where debased discussion is tolerated. Your choice of the term "pure junk" effectively made you part of the subject we're discussing because naturally anybody reading that remark is going to immediately wonder, "who says that and why should I believe him?" As you can tell, your language certainly got my attention. By your language you chose yourself as a topic, Daniel. Please don't complain to me about your choice. -
johnd at 17:38 PM on 30 June 2010Perth forum on climate change: all the gory details
Marcus at 16:11 PM, my response to youir post has been deleted, but your post remains. Can whoever moderated the post explain. If my response was OT, so is the post I responded to. What has happened to the courtesy normally extended if posts are tending off topic? -
Doug Bostrom at 17:21 PM on 30 June 2010What is Global Warming and the Greenhouse Effect?
RSVP, if you're going to quibble with Kevin you'll need to have your facts straight. For starters, you're wrong about how clouds interact with IR. By expressing your confusion as assertions you're spreading your confusion elsewhere. Please don't. -
daniel at 17:19 PM on 30 June 2010Sea level rise is exaggerated
Doug you do a lot of commenting on this website so I don't really know how cosy you are with the authors. I have been absent because my comments have been deemed inappropriate by a rather draconian comments policy. I will assume you know little about that but I am suspicious since you continued to argue with me and seemed to address some of the issues I was raising in those comments. I will address your recent comments soon. I have only skimmed over them now. I would like to say that this comments policy is not endearing to the authors of the website. If you deem your opponents comments as uncivilised, off topic, whacky or inappropriate then you can just casually reply saying as much and allow them to discredit themselves as they rant some more. Only truly foul language should be deleted. Explain to me doug why it is that you can use ad hominem arguments against my credibility by saying that I'm not a climate expert and therefore have nothing to say in regards to the quality of work coming from those fields? It really doesn't look good for you guys. -
RSVP at 17:17 PM on 30 June 2010What is Global Warming and the Greenhouse Effect?
<> Even the simplest of explanations should be consistent with reality. And I doubt that the "general public" you are referring to come to this site, or even have much interest in global warming theories. -
Doug Bostrom at 17:10 PM on 30 June 2010Hockey stick is broken
I smell a rhetorical question. Marty knows enough about temperature reconstructions to speak of "misleading bristlecone pine data" but wants help finding a reconstruction without 'em. Sorry, I'm not biting. Anybody else up for a pointless argument? -
RSVP at 17:10 PM on 30 June 2010What is Global Warming and the Greenhouse Effect?
To Kevin Judd The style of this writing is very good in that it uses simple and straightforward language, however... When seen from above, clouds appear white because they reflect a good part of the visible light spectrum. Clouds appear black underneath, because there is not a lot of visible light emanating from the Earth's surface. If clouds keep heat in as you say, (and I assume you mean locally below the clouds), they must be doing so generally only for IR emanating from the warmed air and surface below the cloud. In addition, they are not absorbing most of this heat but rather reflecting it. This is very different from my understanding of the AGW model which focussed on the heat that CO2 itself is absorbs. When in fact the word "greenhouse" seems to be more applicable to cloud cover as compared to any "transparent" gas, the analogy of CO2 with clouds seems to break down heartily because of the effects of an abrupt reflective boundary between a cloud and non-clouded air; a boundary that does not exist for CO2. Another way to see this would be to assume the Earth were covered completely in clean fog, and ask, would it be cooler or warmer? Or the complement of this question, which would be, "what conditions lead to fog?" -
villabolo at 17:06 PM on 30 June 2010What is Global Warming and the Greenhouse Effect?
#1) Karl_from_Wylie at 14:21 PM on 30 June, 2010 "Article presents a simplistic argument. Nature has more variablity, and more inputs than simply an increase in Carbon Dioxide." ********************************************************************************************** Karl, I believe this post was intended for the general public and is thus kept somewhat simple on purpose. It's not that simplistic, however, when you take note of the fact that you're referring to "Nature". That implies previous events of "Natural Global Warming". However, the focus of this post is about "Man Made Global Warming" in which Carbon Dioxide is the main cause. -
marty at 16:47 PM on 30 June 2010Hockey stick is broken
Can anyone tell me if there are temperature reconstructions that specificall avoid the use of the misleading bristlecone pine data? Cheers -
Doug Bostrom at 16:37 PM on 30 June 2010What is Global Warming and the Greenhouse Effect?
Actually John there is much mentioned of water vapor in anthropogenic climate change research. In short, water vapor is being supplied to the atmosphere in increasing quantities as things warm up and more water vapor makes the problem of warming worse. Here are a couple of helpful articles: Water vapor and global warming Attribution of observed surface humidity changes to human influence I believe there is a new paper being prepared for publication in the coming months that examines cosmic rays and cloud formation. Indeed, some things never change. Geese migrate, papers on cosmic rays and clouds are prepared for publication. -
Phila at 16:35 PM on 30 June 2010What is Global Warming and the Greenhouse Effect?
Whilst much is made of how high CO2 levels may rise to, there seems to be little mention made of how much the water vapour levels will rise and whether there is an ultimate limit. Little mention where? Climate scientists have addressed this issue at length, repeatedly. See Water vapor is the most powerful greenhouse gas, just for starters. It's one thing to disagree with a specific scientific arguments on water vapor, but to act as though it's being downplayed or ignored is kind of absurd, especially for a longtime commenter on this site. In my experience, there are in fact very few "skeptical" arguments and very few uncertainties of which "little mention" has been made by climate scientists. -
Marcus at 16:11 PM on 30 June 2010Perth forum on climate change: all the gory details
My counter to the "CO2 is just the result of the MWP lag" would be this-"where does all the excess CO2 come from?" If you look at the Ice Cores that show the various Milankovitch Cycle driven Glacial & Inter-glacial periods, you can see that CO2 concentrations rarely get much above 260ppm-& *never* get above 300ppm-in spite of temperatures rising by around a couple of degrees above those at any period in the Holocene. All available Paleo-climate data shows that temperatures in the MWP never reached the heights of previous Inter-Glacial periods. So, if this CO2 is from natural sources only, then why did much warmer periods not produce CO2 concentrations of around 400ppm or more? My understanding is that its because ca. 280ppm is the total amount of CO2 available in the Quaternary Era Atmosphere & Carbon Sinks combined. Therefore the only other source for this CO2 (aside from *massive* volcanism) must be coming from fossil fuels formed when CO2 levels were at levels of 1000ppm or above. My other counter would be "show me the 14-C fingerprint that proves the CO2 from natural sinks". -
johnd at 16:03 PM on 30 June 2010What is Global Warming and the Greenhouse Effect?
Comparing CO2 to clouds is wrong. Clouds are not a greenhouse gas. Water vapour is however, and it is always present. Whilst much is made of how high CO2 levels may rise to, there seems to be little mention made of how much the water vapour levels will rise and whether there is an ultimate limit. Clouds are also always present providing between 64% and 69% coverage globally. Clouds provide an overall nett cooling effect for the planet. I believe there is a new paper being prepared for publication in the coming months that examines cosmic rays and cloud formation. -
ScaredAmoeba at 15:49 PM on 30 June 2010What is Global Warming and the Greenhouse Effect?
Karl_from_WylieBias. Increase in Carbon dioxide does not assure Global Warming. There are more variables to the equation.
It is noted that you provided not one shred of evidence for your assertion. You overlooked this:Of course, this is a simplified explanation of global warming, ...
Which rather demolishes the entire point of your post. Perhaps you should learn to read more carefully. Skeptical Science has debunked numerous claims made by a well funded denial industry. Smoke, Mirrors & Hot Air: How ExxonMobil Uses Big Tobacco's Tactics to Manufacture Uncertainty on Climate Science Koch Industries Secretly Funding the Climate Denial Machine Crescendo to Climategate Cacophony Behind the 2006 Wegman Report and Two Decades of Climate Anti-Science - John R. Mashey -
Chris Colose at 15:44 PM on 30 June 2010What is Global Warming and the Greenhouse Effect?
Karl, it's not very useful to tell people through a quick sound byte on the radio that global temperature change is a function of the net radiative forcing. There's nothing wrong with this approach...CO2 is, and will be, the largest forcing agent driving climate change from the pre-industrial/industrial transition era all the way into the foreseeable future. That other things can offset CO2 is important, especially on relatively short timescales, but no other negative forcing is persistent and strong enough to offset our CO2 which will enhance the greenhouse effect on timescales of centuries to millennia. At least not anything within the bounds of physical plausibility. -
scaddenp at 14:49 PM on 30 June 2010What is Global Warming and the Greenhouse Effect?
Well lets see. In terms of energy balance, climate = function(solar, aerosol, albedo, GHG). The complication is indeed feedback. However, if you increase GHG, you need to find a negative feedback that works with increasing GHG to avoid warming. Constraint - this negative feedback has to work in such a way that variations in solar on the earth's surface will also give us the ice ages (or give us an alternative model for ice age cycle). I havent seen anything credible. The much-talked about cloud feedback is response to temperature so if it reduces sensitivity to GHG so much how come it doesnt impede the sensitivity to solar change? -
Doug Bostrom at 14:35 PM on 30 June 2010What is Global Warming and the Greenhouse Effect?
For more fully fleshed-out versions of what Karl_from_Wylie speaks of when he mentions other variables, natural variability and the like, there are numerous articles here on Skeptical Science providing information on those topics. The View All Arguments is a fun place to start. Another terrific resource is a book by historian of science Spencer Weart. His history of this topic The Discovery of Global Warming is freely available for reading online as well as being available in print. -
Karl_from_Wylie at 14:21 PM on 30 June 2010What is Global Warming and the Greenhouse Effect?
"..The message for today, however, is that anyone who tells you that carbon dioxide does not cause global warming, either does not understand the basic science, or is being deliberately misleading." Bias. Increase in Carbon dioxide does not assure Global Warming. There are more variables to the equation. Article presents a simplistic argument. Nature has more variablity, and more inputs than simply an increase in Carbon Dioxide.Response: Increase in Carbon dioxide does not assure Global Warming. There are more variables to the equation.
This issue is examined in detail at CO2 is not the only driver of climate. -
ProfMandia at 13:18 PM on 30 June 2010Perth forum on climate change: all the gory details
Barry, at our current 2 ppm CO2 increase per year, we are increasing CO2 at a rate of just under 2,000 times that of the previous 800,000 years where CO2 ranged naturally between 190 ppm and 300 ppm every 100,000 years. Scott A. Mandia, Professor of Physical Sciences Selden, NY Global Warming: Man or Myth? My Global Warming Blog Twitter: AGW_Prof "Global Warming Fact of the Day" Facebook Group -
David Horton at 11:42 AM on 30 June 2010Perth forum on climate change: all the gory details
The MWP lag suggestion falls into the category of those skeptic mechanisms that rely for their validity on the incredible coincidence that they occur exactly at the time when CO2 pumped out by industry begins to really massively increase. That these arguments all rely on us not noticing that is no coincidence. -
Doug Bostrom at 11:41 AM on 30 June 2010Sea level rise is exaggerated
Hi Daniel, glad to see you back, I was afraid I was going to have to argue with myself. I thank you for forcing me to take a closer look at Donnelly and strain my eyesight squinting at his graphs. I see your point about samples 7 & 8, I'm sure Donnelly would have been happier if they'd resolved better but because they're embedded in the middle of the series their effect is not very drastic; interpretation of those is constrained by the surrounding boxes. As to your problems with multiple date ranges for samples, if you read the text carefully you'll see how Donnelly eliminated date ranges by using methods beyond C14: In some cases we can use the Principle of Superposition to determine which range most likely represents the age of the sample. For example sample 9 should be younger than sample 10 (since sample 9 was recovered 3.5 cm above sample 10), so we eliminate the two older ranges (1306–1356 and 1357–1365 A.D., gray on Figure 2); the youngest range from sample 9, 1386–1440 A.D., best represents the age of that sample. Other sample ambiguities were treated with different methods appropriate to the individual cases, with the result that multiple date ranges appear to have been eliminated in all cases if I'm reading Table 1 correctly. With regard to drawing a line through the whole collection, if I get you right and correct me if I'm misunderstanding you, you're suggesting that it's equally reasonable to pick and draw a series of lines perhaps pointing up and perhaps pointing down between any chronologically linear pair of samples. That's not as conservative as doing what Donnelly did. As well, doing such a series of arbitrary choices leaves the issue that the entire series must begin somewhere within the region circumscribed by the sample 4 and 11 confidence boxes, meaning that the overall conclusion of the series of choices made to connect individual samples ends up being nearly the same, confined by the beginning and ending samples. Meanwhile, it appears that the slope described by the direct recent tidal measurements is inevitably going to be steeper than the sum linear product of whatever combination of ups and downs you might choose to impose on the paleo series, and as well covers a disproportionate vertical range compared compared to the paleo series. This suggests to me that attempting to create and insert arbitrary additional information into the series is pointless. So again my take is that you're suggesting a liberal interpretation of the data, Donnelly is picking a conservative approach. And I do think neither of us are equipped with the specific skills we need to cast technical judgment on this article, certainly not to fling the term "utter junk" in describing it. The suite of dating refinements employed by Donnelly I refer to are an example our ignorance, as I mentioned before. -
topquark at 11:27 AM on 30 June 2010Perth forum on climate change: all the gory details
Re the idea that the current rise in CO2 might be due to an 800 year lag from warming during the MWP: I encountered that argument for the first time a few days ago in Ian Wishart's book Air Con. It seemed unlikely; thanks for the counterarguments. -
daniel at 10:49 AM on 30 June 2010Sea level rise is exaggerated
Here's a quote from the above comment from doug # 31 "If I felt free to draw lines wherever I pleased between the samples it might be possible to squeeze in some excursions, but then I'd not only be substituting fiction for reality, I'd almost have to end up with an implausible looking graph, and again I'd have to be creating data to do so. So my conclusion is that Donnelly's more conservative than Daniel." You wouldn't be substituting fiction for reality doug :) The error estimates allow you to draw those lines. The fiction comes from believing that given the uncertainty in the data points we can conclude that short term deviations from the proposed trend are non-existent. Look at the uncertainty in time for samples 7 and 8, it's approximately 150 years. That means the authors are saying that the assigned height (which has it's own level of uncertainty) lies somewhere in the range of 150 years (between about 1500-1650). That is the time span of the current instrumental record. That should give you an idea of the vast difference in certainty between the two sets of data. Can you see that sample 11 has two date ranges assigned to it? Does that sound like a high level of certainty to you doug? We can see also that sample 9, which by the authors own admission should be younger than sample 10, has a date range generally older than sample 10. How much of sample 10's 95% confidence interval can actually be so confidently assigned when sample 9's 95% confidence interval is not even as young as that? It's true statistical methods lead to these confidence intervals but then logic needs to be applied before we write our conclusions section. That portion of the graph, 1300-1500 AD, has a lot of potential for a significant deviation from the proposed trend. As does 1600-1750 AD, if we could more confidently assign samples 7 and 8 toward the younger end of their current 95% confidence intervals then a short term trend of much greater than 1mm/year SLR through sample 5-8 could potentially exist. If such deviations from the trend were visible then the recent sea level rise would not be as alarming as is made out to be. These short term rates of paleo sea level rise do not even have to match the 2.8mm/year observed in recent times it only has to be closer to it than the average 1mm/year in order for the recent rise to be less alarming. The low resolution data really undoes the conclusions of Donnely et. al. but we find that although the Gehrels paper tries to address this issue the uncertainties are still too high to obtain a meaningful result. These attempts to measure paleo sea level rise are certainly commendable for the level of effort put in but the conclusions drawn are unsound. -
Riduna at 10:00 AM on 30 June 2010Perth forum on climate change: all the gory details
All good stuff but in a city with a population of well over 1 million, attendance by 200 does seem a bit disappointing. Perhaps there is already wide acceptance of AGW and knowledge of how to deal with it in the community, though I doubt it. Has there been good press coverage? What follow-up is planned? Maybe a practical demonstration of how individual households can reduce their carbon footprint? -
scaddenp at 09:20 AM on 30 June 2010CO2 is not a pollutant
AWOL - lets ignore the completely hilarious non-physical stuff about venus. The point I was making is that you cant live on venus, there IS an upper bound on temperature and if you chose enough of powerful enough GHG, then we turn earth that way too. The MAIN point I was making is that RATE of change is the cause for concern - too fast for ecological systems to cope with. Current rate of change is too fast, let alone the projected future rate of change. Its the rate that is the problem. Your happy scenario might play out over 1000s of years and as for comments on deltas, I assume you dont live on one. This is fantasy stuff. Ask yourself why all the existing drowned deltas are the happy places you imagine and they drowned with sealevel rates much slower than current and projected. As for CO2 is plant food. Please see other comments in this thread and some reputable science. CO2 does not magically gives the plants extra water or nutrients. -
johnd at 08:50 AM on 30 June 2010Watts it like at a climate skeptic speakers event?
Chris G at 08:00 AM, is not the climate, at the most basic level, self regulating within limits determined by the properties of H2O and in particular the points at which it changes state? -
johnd at 08:44 AM on 30 June 2010Watts it like at a climate skeptic speakers event?
Marcus at 09:41 AM on 23 June, 2010, I have posted at response over at "CO2 is not a pollutant" having had it deleted from here. I have also copied your post over there as part of my response to provide continuity even though your post has been allowed to remain here. -
johnd at 08:38 AM on 30 June 2010CO2 is not a pollutant
This post is a continuation of a discussion at the thread "Watts it like at a climate skeptic speakers event?" in response to post 104, Marcus at 09:41 AM on 23 June, 2010. The Marcus post remains at that thread whilst my reply was selectively deleted. I have copied the Marcus post here to provide some continuity, it follows after my response. My response:- The most obvious point being overlooked is that the limitations listed are not new, nature has RARELY provided ideal conditions, some would swear never. The less than ideal conditions have been there ever since agriculture was first developed, especially, ESPECIALLY, in Australia in the regions similar to where the Horsham FACE trial was conducted which not only simulated higher CO2 levels, but HOTTER and DRIER conditions as well. So far 3 trials have been done over 3 years, 3 below average years, and are ongoing. A couple of points :- (1)Seed yield increased significantly whilst seed protein fell slightly EXACTLY as has always has happened under natural conditions. Nothing new there. (2)Protein yield per hectare INCREASED meaning the process of producing more food from less land can continue. (3)Increased non-grain biomass assists in improving soil carbon content. To increase soil carbon content by 1 tonne per hectare, an extra 4.4 tonnes of dry matter per hectare has to be returned to the soil. (4) Irrespective of CO2 levels, higher outputs require higher inputs of water and nutrients. ALWAYS HAS. However indications are that under higher CO2 levels, water utilisation efficiency is INCREASED. ---------------------------------- Marcus at 09:41 AM on 23 June, 2010 Sorry moderator, but I just can't let John D's latest comments go by without a response. You seriously don't get it-do you John? Nobody here has claimed that-under ideal conditions-CO2 *can't* be a plant food. What they've claimed is that its not that simple because (a) global warming won't provide for ideal conditions & (b) that it is nitrogen, water & trace elements that are more limiting factors on plant growth than CO2 abundance. For all your talk, you've not managed to answer several key questions which are: (a) under ideal conditions, can increased CO2 levels enhance plant biomass for the long-term, given acclimation? (b) even ignoring acclimation, can increased CO2 levels enhance plant biomass given a warmer & drier environment? (c) will increased vegetative biomass, from increased CO2 levels, automatically translate into significantly greater seed yields? (d) does increased quantity of edible biomass automatically translate into increased *quality* of edible biomass. (e) will increased CO2 levels impose any additional costs on farmers? (very important given the slim margins on which most farmers operate). Based on the evidence provided by the *one* FACE trial you've linked to, I'd say the answer is that, (a) though increased CO2 can provide short-term increases in total biomass (under ideal conditions) acclimation might eventually erode those benefits; (b) that though there was a significant increase in total plant biomass, this wasn't translating into significant increases in seed yield for most varieties & (c) that seed quality (in terms of protein content) was decreased, but total nitrogen demand from the plant was increased. As someone who actually deals with farmers on a regular basis, if you were to try & promote that to farmers as a *benefit* from increasing CO2 emissions, they'd probably laugh in your face-rightly pointing out that ideal conditions are already hard to come by, that seed yield & seed quality are all that's ultimately important, & that they would be ill-equipped to afford the significant increase in fertilizer costs that this enriched CO2 environment would demand. ----------------------------------- -
Doug Bostrom at 08:16 AM on 30 June 2010Sea level rise is exaggerated
Upon further scrutiny of my last post, I think it communicates poorly the conservative nature of Donnelly's interpretation of his samples versus Daniel's assertions concerning hidden slewing. Daniel posits There is more than enough slack in this data to periodically reproduce the apparently rapid sea level rise of 2.8mm/year in the NYC tide gauge data of the last ~150 years (cited and compared to by the authors). Donnelly on the other hand sticks to the available data. Looking at Donnelly's figure 2 where he marries together the various data I think shows how Daniel might be right that while short episodes of discontinuous rise and fall may indeed be invisible, a linear interpretation not only avoids speculating signal features where none can be derived from the data but in fact more likely yields a result that is plausible on its face. Supposing for a moment that we are free to make up data however we please, how exactly would discontinuities of the kind Daniel imagines may have happened actually fit within the constraints of connections between the samples while still connecting to the more recent instrumental record? If I felt free to draw lines wherever I pleased between the samples it might be possible to squeeze in some excursions, but then I'd not only be substituting fiction for reality, I'd almost have to end up with an implausible looking graph, and again I'd have to be creating data to do so. So my conclusion is that Donnelly's more conservative than Daniel. Here's the figure from Donnelly by way of illustration:
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VoxRat at 07:22 AM on 30 June 2010Perth forum on climate change: all the gory details
The photo in the post needs a caption. Who's who?Response: Good point, caption added. Thanks for the suggestion. -
kdkd at 06:31 AM on 30 June 2010Astronomical cycles
Ken #110 The main flaw in your argument is that you assume a perfect measurement model through space, time and instrumental precision. As none of these conditions are met, your entire argument is invalid. -
Peter Hogarth at 06:11 AM on 30 June 2010Sea level rise is exaggerated
daniel at 22:03 PM on 26 June, 2010 I did make an assumption and I apologise, I'm not sure where that came from, but it was late! Perhaps "The article claims that skeptics are guilty of interpreting small recent trends from noisy data as significant" figure 1 etc. I assumed this was an oft used reference to the Jason 1 satellite altimeter data showing a decrease in trend a couple of years back (not a decrease in level, it appears we both got the wrong end of the stick), that's what I meant anyway. More relevant to your debate, see Grinsted 2009 which is pertinent to your points on sea level reconstructions. There's a few more I can dig out if of interest and I get time. I'm not sure "Therefore it is invalid to conclude there has been a significant recent increase in sea level rise" is really supportable. Doubt whilst you accumulate more evidence would be ok. -
Peter Hogarth at 05:12 AM on 30 June 2010CO2 is not a pollutant
AWoL at 04:22 AM on 30 June, 2010 "What's good for plants is good for animals which is good for people" Joseph Priestley might have had something to say about this! -
Tom Dayton at 04:50 AM on 30 June 2010CO2 is not a pollutant
AWoL, regarding the benefits of CO2 itself for plants, see the comments before yours on this thread. Click on the links within those comments for supportive details. Regarding your other contentions, see the broader post It’s not bad, which lists positives versus negatives of not just more CO2 for plants to consume, but of all the effects of higher CO2 levels, including warming and ocean acidification. -
Doug Bostrom at 04:50 AM on 30 June 2010CO2 is not a pollutant
Quite a bit of unsupported speculation there, AWoL. Other people with skills specific to the various spheres of knowledge you touch upon draw different conclusions. Anyway, with regard to unchecked formerly insignificant pollutants emerging from burgeoning cultural intensity we have lessons from the past to draw upon. Government (us, acting in concert) ends up owning solutions nobody else can or will provide. For a specific example of effective solutions to pressing need arising from inadvertent effects of commercial activity in combination with exploding demand see the example of cholera and typhoid emerging in London and other developing urban systems. A key feature of this story is that established commercial forces nearly invariably resisted attempts to solve the fundamental causes of these diseases, leaving the public in the form of government eventually forced to insist by agreed-on coercion. -
Baa Humbug at 04:44 AM on 30 June 2010What causes the tropospheric hot spot?
It's 4.45am here so i need to excuse myself. Don't read anything into my silence please. And thanks to all those who replied -
Baa Humbug at 04:26 AM on 30 June 2010What causes the tropospheric hot spot?
The 2 to 2.5 was my understanding and I concede that I can't at this time put my finger on where this figure came from. So I'm happy to take your quoted figure of 1.25 However this 1.25 is GLOBAL MEAN. The hot spot is supposed to be most prominent over the oceans and over the tropics (as shown by chart C 30N to 30S) Unless the colours of my computer screen are off, the legend on these charts show a warming of 2 to 3 times than that of the surface ( 0.4 to 1.2) The charts kindly provided by Peter at #54 show tropospheric warming mainly in the high lattitudes, but very little warming along the equatorial band. like wise with the stratospheric cooling. There is a discrepency there (in relation to the hot spot hpotheses) that I can't explain, maybe someone else can. -
AWoL at 04:22 AM on 30 June 2010CO2 is not a pollutant
Apologies to the Moderator. I posted in the wrong place as a result of not properly familiarising myself with the layout,prior to posting. # AWoL at 07:28 AM on 29 June, 2010 I'm just a vet, though believe it or not, I can remember Boltzman's Constant from our old Physics lectures, so I like to believe that I inhabit the ranks of the scientific semi-literate. My question is, if the Earth has an arbitrary average temperature of circa 15degC and the temperature of space is 270degK ie -270degC, then what's the problem? Anything that stems the ferocious heat loss to the exterior, surely has to be a good thing? Surely the correct thing to do is to pump CO2( or more potent greenhouse gases) into the atmosphere in order to keep the planet as warm as possible? What a nutty idea , I hear you say, but in reply I say....-270degC, out there. Not much chance of too much warming when you're up against that. It's bloody cold out there! # scaddenp at 08:14 AM on 29 June, 2010 Awol - "as warm as possible". Why not even more potent GHGs then and get us to Venus-like temperatures? Well obviously because we want planet to be around the temperatures we evolved to live in. However, this debate isnt really about what would be an optimal temperature but is about how fast we are changing it. Think of your farm animals and about how easily farmers are able to cope with rapid climate change. We have huge urban centers and complex food production systems that have developed in stable climate. Rapid change is not good for them. Ask how farmers on the great deltas are going to cope with coast erosion and salt incursion as sealevel rises as well. Over a 1000 years (ice cycle type change) possible. Over 100 years - hmm. AWoL replies scaddenp has given an answer of sorts,but I have to say I'm not entirely satisfied. The Venus comparison is no good as there is a lot of controversy over the workings of the Venusian atmosphere.Most agree that it is not comparable to Earth, and in fact the greenhouse effect of CO2 plays but a small part in explaining the high surface and atmospheric temperatures on that planet. Regarding the consequences of the overheated planet which you envision. Why all the doom and gloom? In the deltas that you mention, could not the farmland, assumimng that there is any, be replaced with fish-farming and shellfish production? People could live on man-made islands as have been constructed in Dubai.In Japan and Hong kong hasn't there been considerable land reclamation? Then there's the Dutch and their dykes.Isn't nature herself lending a hand in the creation of new land ie the Surtseys and the Icelandic Westmann Islands. Isn't isostatic rebound still underway from the last ice age? Or has that come to a stop? With regard to agricultural production, I can't help feel that you are miles off the beam. Wasn't it Herschel the astronomer, that correlated increased sunspot activity with lower grain prices? Everything starts from plants. What's good for plants is good for animals which is good for people.Plants like the heat,given adequate water, and they positively love CO2. Where you, scaddenp,see doom and disaster, I see formerly barren territories transformed into luxuriant swards and dense woodlands, inhabited by contented happy people. That's the bit I don't get. Why is climate change, ie getting hotter, always accompanied by doom and disaster when if anything it is more likely to be accompanied by happiness and prosperity? Any changes are not going to happen overnight, so there's plenty of time to react.And never before have people been able to move so rapidly, and easily establish new settlements, thanks to the extra power to their elbow of readily combustible,energy-dense hydrocarbons.Markets and the intiative of adaptable people will solve any problems far more effectively than any number of governmental organisations. The Sahara was once green. There was no UN in those days.The people didn't die, but moved, adapted and went forth and multiplied......and very good at multiplication they were ..... a bit too good, for their own good, I sometimes think. -
What causes the tropospheric hot spot?
Humbug, Here is the RSS image from the Wikipedia article Peter was referring to:
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Time range is 1979-2010. From this you can see clearly that your assertion was incorrect, stratospheric cooling + troposheric warming is empirically measured, it doesn't just come from models.
Also note that the tropospheric hotspot is a distinct concept from stratospheric cooling + tropospheric warming. The tropospheric hotspot is a greater warming of the troposphere in lower latitudes relative to higher latitudes. This is a prediction that follows from any warming, not just from CO2. Stratospheric cooling is the cooling of the stratosphere while the troposphere warms across all latitudes. This prediction is unique to warming from GHG's. Figure 1 in this post shows a combination of these two predictions.
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Ned at 03:51 AM on 30 June 2010What causes the tropospheric hot spot?
Baa Humbug, can you explain where you got that "2 to 2.5" factor from? I don't know a lot about that side of things, but my understanding was that the models estimated an amplification factor of about 1.25 globally (1.4 over the oceans and 0.95 over land). But I could easily be misunderstanding either you or the literature (or both)! Also note that the top panel of Peter Hogarth's graphic shows the middle troposphere, not the lower troposphere.
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