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Comments 96401 to 96450:
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scaddenp at 12:25 PM on 8 February 2011Global Warming and Cold Winters
Mozart - "albie" and "Danny" are somewhat impolite ways to refer to other posters. I'm Phil, by the way. On topic, the paper in question looked at a mechanism by which the changing albedo in arctic sea (recent) could impact on the arctic polar circulation. The effects are local to parts of Europe and parts of US. The data is drawn from that corridor, and yes, overall, europe and US are warming like the rest of the world. I think the paper is interesting, plausible, but I agree that the time period is way too short for any evaluation of this account for what is a weather rather than climatic phenomena. The point of paper is that colder winters in some parts of the world are not necessarily at odds with the overall rising global temperatures. -
Michael T. at 12:19 PM on 8 February 2011Articgate: perpetuating the myth that Arctic sea ice has recovered
Here is the NSIDC graph of April Arctic Sea Ice Extent from 1979 to 2010 showing a clear longterm decline in extent even since 1989:Moderator Response: [Daniel Bailey] Fixed URL. -
Daniel Bailey at 12:09 PM on 8 February 2011Climate Change Impacts on Ocean Ecosystems
Gee, first the phytoplankton news, Dai 2010, now this... What's next, Cryosat-2 showing we're one strong Arctic DiPole summer away from Santa's Workshop going Waterworld? Make room at the bar, I'm buyin'... The Yooper -
Alden Griffith at 12:07 PM on 8 February 2011Crichton's 'Aliens Cause Global Warming'
@BernAs I understand it, the 'consensus' in climate science comes in the answers to the question: "If we change the amount of CO2 in the atmosphere, how much does the Earth's climate change in response?"
I would suggest that the "consensus" is not around sensitivity, but is simply based upon the reality of climate change as put forth in the IPCC AR4: "Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations." ...and that increasing greenhouse gases will continue to warm the planet. Climate sensitivity represents a large source of uncertainty. However, there is strong agreement that it is unlikely to be low (and that most of this uncertainty is not comforting). -
adelady at 11:57 AM on 8 February 2011Climate Change Impacts on Ocean Ecosystems
Think I'll join kr at the bar. Thanks anyway, John. We need to know this even if we don't want to. -
climatesight at 11:50 AM on 8 February 2011How We Know Recent Global Warming Is Not Natural
Nice summary, John. Well done. -
mozart at 11:42 AM on 8 February 2011Global Warming and Cold Winters
Figured what out Albie, that the temperature was way lower than normal in Europe and North America because a high was displacing Arctic air? Isn't that always the reason for really cold air? But I guess the difference here is the high was supposedly caused caused by global warming effects on the ice cap. Now this loss of ice hasn't happened suddenly this year. So if we follow this line of reasoning we should have seen a succession of colder winters. Unfortunately here things break apart. We have seen generally warm winters in North America, apart from last year and this year. We can't even discern any trend towards colder winters. So sorry....it's a nice theory, elegant almost.....but it just doesn't hold up. Just another attempt to make any result, warming or cooling, the result of man's insouciance. I know Albie is too busy to respond, but I'm wondering, am I still on topic Danny? -
Marcus at 11:40 AM on 8 February 2011Crichton's 'Aliens Cause Global Warming'
I don't wish to speak ill of the dead, but from reading some of Michael Chrichton's books, he seems to have a very dim view of science in general. In Jurassic Park, for example, he effectively uses the Malcolm character to bag the entire scientific establishment. Also, having been a scientist for well over a decade now, I don't see much of it that's based entirely on *hard* fact. My own field-biology-is largely based on theories that are backed by all the available evidence-but these theories often find themselves being challenged. A classic case is the so-called "Central Dogma" which goes DNA--->RNA--->Protein. Now this "dogma" held up pretty well until the 1970's, but then was challenged by the discovery of RNA viruses & retro-viruses. The next challenge came in the 1990's, when prions were discovered. It took a lot of evidence, though, to overturn the established consensus, but that's always how good science has been done. Perhaps if these so-called "skeptics" spent a little more time gathering said evidence, & less time bagging scientific consensus, we might take them just a bit more seriously. -
dorlomin at 11:39 AM on 8 February 2011Climate Change Impacts on Ocean Ecosystems
Bleak. -
Climate Change Impacts on Ocean Ecosystems
John Bruno - Thank you for posting this. I think I need a beer now. Possibly several... -
Albatross at 10:59 AM on 8 February 2011Global Warming and Cold Winters
Mozart @129, "why do we have 6 new record lows in Mexico?" You are fishing, but i'll bite. Look at the loading patter for the AO. The AO was incredibly low in late November and December, which probably led to some cold outbreaks as cold air was pulled southwards over the lower latitudes of N. America:Observed 500-mb height anomalies for last 30-days, [Note the below average heights extending as far south as the Gulf of Mexico, Florida experienced record cold weather recently]
The result as far as temperatures are concerned.....
With a bit of effort mozart you could have easily figured this out for yourself. Now I have more important things to do.
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WheelsOC at 10:58 AM on 8 February 2011Crichton's 'Aliens Cause Global Warming'
I can't tell you how often I see somebody sneering at the consensus of anthropogenic climate change, as if consensus kicked their dog and burned their house down. I know that a lot of it has to do with Crichton's essay because it's frequently been cited directly, but I don't imagine it hasn't been working beneath the surface for the people that deny climate change without invoking the essay directly. It never ceases to amaze me how quickly and vehemently people will turn to non-scientists to combat the expert opinion on a subject. -
Bern at 10:54 AM on 8 February 2011Crichton's 'Aliens Cause Global Warming'
@adelady: I agree, however climate science has plenty of hard facts of it's own: - the Earth absorbs light from the Sun - the Earth re-emits that energy as infrared radiation - CO2 absorbs infrared radiation, and re-radiates it in all directions - CO2 and other greenhouse gases absorb significant amounts of infrared radiation from the Earth, and re-radiate some of it back down to the Earth - because of the above, the Earth is considerably warmer than simple radiative equilibrium suggests it should be (lucky for us!) The first four points are measurable, and are about as hard as facts can get. The fourth relies on an understanding of radiative heat transfer, but that's been studied for a very long time, and the 'model' involved has been exceptionally well tested & verified. I understand an overly simplified 1-dimensional model will predict the average global temperature to within a degree or two. As I understand it, the 'consensus' in climate science comes in the answers to the question: "If we change the amount of CO2 in the atmosphere, how much does the Earth's climate change in response?" Because of the uncertainties involved in determining climate sensitivity, and the fact that we don't know everything there is to know about how the Earth's climate works, we can't pin that down to a single number. But some very smart people working on the problem have narrowed it down to a range of results, with a most likely number of about 3ºC of warming per doubling of CO2. For some odd reason, it turns out that adding another blanket to your bed makes you warmer... (I've never understood those people who argue negative feedbacks cancel out the effects of CO2 increases - I mean, have they never looked at the paleoclimate records? That doesn't look like a self-regulating stable system to me!) -
muoncounter at 10:50 AM on 8 February 2011Global Warming and Cold Winters
#129: "why do we have 6 new record lows in Mexico?" Perhaps you should study the distinction between weather and climate. See the thread "It's freaking cold". Then look at maps of the jet stream, which is pulling very far to the south, in part because of the anomalously warm Arctic. Also see the thread on "extreme weather". In fact, do as Moderator DB suggests; read and learn before developing so many opinions. -
muoncounter at 10:44 AM on 8 February 2011Global Warming and Cold Winters
#119: "In this subject treating data as factual, is a mistake." Wow, doesn't that just say it all? -
scaddenp at 10:42 AM on 8 February 2011Global Warming and Cold Winters
"You refer me to a site with wildly varying estimates, most of which are hopelessly out of date following the Global near depression. " I sent you to site from which the scenarios used for IPCC models are taken. The models are run for each scenario so you can see what happens. You appear not to have read the assumptions on economic factors. As to idea that they are hopelessly out of date. see CO2 since 1990. Can you see the global depression is that curve? "Energy usage from all sources will increase 48% by 2035," How about putting in links? I assume this global not US? "So, even assuming we can't drive any efficiencies in carbon per unit of energy....we don't double carbon output from man made sources." Dont need to. As has been pointed out, do your maths. " And man made sources constitute a fraction of total CO2 production." Another skeptic dance. Natural sources AND sinks are huge but balanced. The increase in CO2 in the atmosphere is mostly manmade. See appropriate threads. "Given this and the relatively small rise of 23% in CO2 since 1900, I find your confidence in these wildly differing estimates, bemusing to say the least. " Your erroneous maths on this subject has been pointed out many times. Start at 1950, 310ppm, and add 2 ppm per year. -
mozart at 10:33 AM on 8 February 2011Global Warming and Cold Winters
Well here's one for you to ponder Albie, and it's on topic. If an Arctic high pressure region caused by warmer sea temperatures is causing all this misery....why do we have 6 new record lows in Mexico? Refer to my off topic response 104. -
RickG at 10:33 AM on 8 February 2011Global Warming and Cold Winters
@126 mozart First digest the two links I gave you and especially the links provided in those articles. It is not something that is ignored or even looked upon lightly. The point I was trying to make with the anomalies is that a change of 1 deg C is a change of 1 deg C whether it occurred in a UHI or twenty miles from it. The UHI actual temp change may be 17C to 18C and the station 20 miles away may be 14C to 15C. Different temperatures but still only a change in 1 deg C. -
scaddenp at 10:25 AM on 8 February 2011How We Know Recent Global Warming Is Not Natural
Pirate - you keep bringing up the "CO2 lags temperature".Do you think this that is an unexpected result within current climate theory? (Its not). See CO2 lags temperature for more discussion. -
Albatross at 10:17 AM on 8 February 2011Global Warming and Cold Winters
I also showed you the SSTs @125, which you of course ignored, instead once electing to keep arguing about a long debunked point. Now, please either stay on topic move the discussion to the appropriate thread. Thanks. -
mozart at 10:11 AM on 8 February 2011Global Warming and Cold Winters
Ah but Rick that's exactly my point.....change is what we are after, and cities and heat islands are growing. There is every reason to believe, even with stable temperatures, readings taken in cities will continue to rise. By contrast there is no reason that a reading taken in the city or the country would fall over time. We have a built in bias. Now as Albie points out above serious attempts are made to eliminate this bias. But I'm from Missouri on this one, I doubt the effects are totally eliminated at all the sites records are kept, in every country around the globe. But as Daniel would say, I'm off the subject and wasting your time...so best not go there.Moderator Response: [Daniel Bailey] UHI is off-topic on this thread. Find the appropriate thread for continuing discussions of that topic. Thanks! -
villabolo at 10:08 AM on 8 February 2011Articgate: perpetuating the myth that Arctic sea ice has recovered
Alden Griffith @4: "Imagine a student in their graduate-level comprehensive exam trying to make a claim based on two data points that completely misrepresents the clear longterm trend." You can actually imagine a mere layman, who does not even pretend to have the ability to read charts, finding intuitively something very wrong with that picture. If we were to actually run into a layman using such a chart, it would be instructive to emphasize the visual emptiness of the chart. That should arouse suspicion in his mind. -
Albatross at 09:45 AM on 8 February 2011Global Warming and Cold Winters
Mozart @122, Oh dear, nobody is claiming that the UHI does not exist...that is why they correct for it, and they are very careful. Let me remind you of the title of this post "Global Warming and Cold Winters", it speaks to the intriguing hypothesis that the loss of arctic sea ice could be responsible (at least in part) to the AO going into deep negative territory. The result...temperatures running 15-20 K higher than normal in the Canadian Arctic and Greenland, and much below average temperatures over portions of Eurasia and N. America. According to the RSS data, lower tropospheric temperatures (70 S to 82.5 N) in November were near record highs, with positive anomalies in December and January-- and that despite one of the strongest La Ninas on record and despite the strongly negative AO. By comparison, a weaker (but significant according to the MEI) La Nina event in 1988-1989 resulted global lower tropospheric temperature anomalies that were over 0.3 K lower than are being observed for this strong event. The very first point you made is that we are still observing record lows as evidence that we do not have a problem. That is simply wrong, and runs contrary to you claiming that the UHI is allegedly causing record highs. On the one hand you are arguing that the record highs are because of UHI (they are not), and on the other hand you claim the occurrence of record lows as evidence that there is not an issue. You want it both ways. Such internally inconsistent arguments are frequently made my "skeptics". The UHI crutch cannot be used "skeptics" to explain away the increase in global SSTs, satellite data, loss of sea Arctic ice, loss of ice from glaciers and ice sheets, earlier leaf burst, changes in migrations et cetera. The figure below shows the global SSTs, no UHI there mate....and if you want a peer-reviewed paper, here is one by Rayner et al. (2005).Now here is an exercise for you...superimpose on that map above the global SAT temperatures. You will find that they correlate extremely well. You continue to argue straw men and continue make unsubstantiated comments. I am not interested in your opinions or musings, I am interested in the science and facts. Such internally inconsistent arguments are frequently made by "skeptics". You are, of course entitled to your opinions on this, but you are not entitled to your own facts.
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adelady at 09:41 AM on 8 February 2011Crichton's 'Aliens Cause Global Warming'
I've always held the view - call it a prejudice if you feel unkind - that much of the pseudo-scientific criticism of climate science is driven largely by a 19th century view of science. It's supposed to be about incontrovertible 'hard' facts. The idea that science is really about complexities and uncertainties is very hard to swallow for those of this persuasion. Crichton certainly exhibits this and many comments on blogs also display a plaintive underlying tone of 'why isn't this easy to understand'. People accept 'the science' to a much greater extent in mysterious invisible areas like endocrinology or cosmology. When it's something we feel that can see or touch many people think understanding it should be just as simple. It never is. That's why it's a field of scientific endeavour rather than a description of the colour yellow. -
RickG at 09:39 AM on 8 February 2011Global Warming and Cold Winters
Mozart: ...the heat island effect needs to be considered. One thing you may not understand is that when you see temperature representations that they are reported as anomalies to a specific base period. In other words its the change in temperature that matters not the actual temperature. You might also look at the discussion on the heat island effect here and here on this site. -
mozart at 09:35 AM on 8 February 2011Global Warming and Cold Winters
Fair enough Daniel, but I just sense the welcome is a little cold (if you'll forgive the word). Skeptic, as a term for those who need more proof, seems to understate things a little bit on this site. Heretic seems closer to the truth, when I weigh this little string. No matter I'll soldier on, from time to time. You chaps need a little debate and above all a little humour. Regards. -
Marcus at 09:27 AM on 8 February 2011Articgate: perpetuating the myth that Arctic sea ice has recovered
What I notice from figure #2, now that I can see it clearly, is that 1989 had an unusually low *maximum* extent for the 1980's (by about 0.5 to 1 million sq. kilometers), which is probably why they've chosen that over-say-April 1988 vs April 2008. This is, again, no different from choosing 1998 as a baseline for recent climate change-because it was an unusually hot year for the 1990's. As I said above, the dishonesty of the Denialists is just beyond the pale, yet look how quickly they prosecute even very honest mistakes by the other side! -
Rob Honeycutt at 09:10 AM on 8 February 2011How We Know Recent Global Warming Is Not Natural
apiratelooksat50 @ 49 said... "I'm on record of saying that I am willing to consider CO2 as a contributor to global warming." So, you're willing to consider basic, well established, 150 year old physics? That's a good start. You'd be surprised how many can't even get that far. -
mozart at 08:54 AM on 8 February 2011Global Warming and Cold Winters
Sorry old chap, but reading that data, they aren't denying that heat island effects exist. They are simply saying it doesn't affect the global record. That record is of modest temperature increases.....I accept that. But the effect on local records can be significant even if hard to quantify. Look at it this way.....nothing is influencing local minimums down....but according to the very article you site the heat island effect can influence local maximums up. Sufficient reason to be careful.Moderator Response: [Daniel Bailey] Let's start over: Welcome to Skeptical Science! Newcomers typically are urged to Start Hereand then read the Big Picture, after which I urge them watch this. Skeptical Science is an immense resource for those coming here to learn about the science of climate, climate change, the human attribution of it and skeptic's arguments against it. In that regard, you are encouraged to use the Search function in the Upper Left corner of every page. Why? To save everyone time. Chances are there's already a post on one's question and a thread discussion of it. After using the search function, if you still have questions, post them on the most relevant thread & someone here will answer it in due time. Thanks! -
Albatross at 08:43 AM on 8 February 2011Global Warming and Cold Winters
Mozart @119, I was addressing your claims, let us deal with those OK? No need to obfuscate or turn this into a "he said, she said". re: "....pinch of salt because of cherry picking of measurement sites. Many, for example are airports, where the heat island effect needs to be considered. In this subject treating data as factual, is a mistake." Absolute nonsense. That myth and fallacy has been addressed by Menne et al. (2010), as well as by the CCC group. Please stop perpetuating myths and insulting us all here with long debunked (and oftentimes unsubstantiated) contrarian speaking points. -
Global Warming and Cold Winters
mozart - I strongly recommend using the "Search" box. For example, a quick run with "heat island" produces this link, while Temp record is unreliable is even listed on every page of this site, on the left border. If you post on the appropriate page a proper discussion can occur - otherwise we get a scattershot on all threads, and it's difficult to actually follow the issues. Incidentally - both skeptic arguments are incorrect. -
mozart at 08:30 AM on 8 February 2011Global Warming and Cold Winters
Albatross I am no more cherry picking than Sweet is by mentioning Greenland. You will note in my posting above I point out it has no significance. Furthermore these record highs have to be taken with a pinch of salt because of cherry picking of measurement sites. Many, for example are airports, where the heat island effect needs to be considered. In this subject treating data as factual, is a mistake. But there I go off subject again.... -
Global Warming and Cold Winters
mozart - Each and every one of your claims about highs and lows is answered here. -
mozart at 08:26 AM on 8 February 2011Global Warming and Cold Winters
Well KR I'm working off today's energy usage and temperature so today's Co2 seemed more relevant. But I gather I'm off topic, so it's moot. Apologies and regards to all. -
Albatross at 08:23 AM on 8 February 2011Global Warming and Cold Winters
Mozart, you are cherry picking by showing data for 2011 to date, it is only early February for goodness' sakes, those data are not even representative of the boreal winter (austral summer), never mind the meteorological year. Look at 2010, and report back what was observed. That said, to do this properly one has to look at the trends over many years. As demonstrated by Meehl et al. (2009) the ratio of record highs to record lows in increasing. note that the ratio is changing, no-one said no new record minimums will be set, just fewer. Michael sweet, 19 all time national record highs were set around the globe in 2010, not 17 (see here). -
muoncounter at 08:06 AM on 8 February 2011How We Know Recent Global Warming Is Not Natural
#47: "these questions remain to be answered" I'm not buying it. Those questions are answered numerous times on SkS, often in discussions in which you've participated. Yet you continually return to the unsubstantiated 'natural cycles' hokum. Perhaps you should be the one answering the questions: what natural cycles are you proposing? what are the 'natural forcings'? Have they already been considered in the models that require an anthropogenic forcing to match the temperature record? Do they stand up to scrutiny? Or do you propose 'magic clouds' a la Spencer? "if we've only had 0.8 degree C warming in the past 150 years" It's the 0.8 degree since 1965 you should be concerned about.#49: "climate has regularly cycled through glacial and interglacial periods." Not relevant to the current situation. You're a science teacher, stay on task.
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Global Warming and Cold Winters
mozart - "So I conclude a doubling of the CO2 extant today, is a long, long way off." The proper term for that line is moving the goalposts. The discussion on this is doubling CO2 from pre-industrial levels, not from what they were yesterday. Secondly, folks, temperature record discussion belongs on Record high temperatures versus record lows. Moderator(s) - I believe this CO2 offshoot is well off-topic? Any suggestions for a more appropriate thread?Moderator Response: [muoncounter] Tried that here; Mozart apparently feels he can dance to his own tune. Move CO2 discussion to a CO2 thread, please. -
mozart at 07:57 AM on 8 February 2011Global Warming and Cold Winters
Sweet...show me where I said they were national records. I haven't seen any national records yet for 2011. So we expand it to a much broader data base of global cities. And please don't say "cherry picked" when I produced the entire list. -
mozart at 07:54 AM on 8 February 2011Global Warming and Cold Winters
Well KR I appreciate those comments, but to me it seems reasonable to believe two things: 1) We will become more carbon efficient in our energy needs, motivated primarily by economic forces. 2) The oceans will continue to absorb 50 to 55% of atmospheric CO2. So I conclude a doubling of the CO2 extant today, is a long, long way off. But that's just my guess. I could go on about the trade-offs but then scadden would discipline me again, and who needs that. -
michael sweet at 07:47 AM on 8 February 2011Global Warming and Cold Winters
Mozart, My original post was 17 national all time records. You have not posted any national records. Who has temerity? -
michael sweet at 07:46 AM on 8 February 2011Global Warming and Cold Winters
Mozart, Quickly scanning your site I see that none of the points you cherry picked are national records. Since it is currently winter in the Northern Henisphere and all the records are land based you would expect more cold records than warm records to be set in the past two weeks. There is more land in the Northern Hemisphere. Your hand picked records do not compare to the 17:1 ratio of All time National hot versus cold records set in 2010, and the yearly record is not biased hot versus cold. I ask you again: what does the ratio have to be for you to be convinced it is not natural: 25:1, 100:1 or 1000:1? -
mozart at 07:43 AM on 8 February 2011Global Warming and Cold Winters
Sweet your counter example was an example of one....Greenland. How you have the temerity to criticize a straight data pull that notes places in 5 different countries is astonishing. -
Bob Lacatena at 07:40 AM on 8 February 2011Articgate: perpetuating the myth that Arctic sea ice has recovered
Here's figure 2, with the contrast slightly improved (and a bad case of jaggies to go with it): -
Global Warming and Cold Winters
mozart - The 4.15 ppm/year rate with 80% industrial expansion discussed in my previous post assumes that the same percentage of CO2 produce (just under 50%) is absorbed by the oceans. If oceans are limited to absorbing 2ppm/year as they currently are doing, then the rates by 2050 (again, using your numbers) will be 5.75ppm/year increase in CO2 for 80% increase in industrialization - still 2.3ppm/year with no change in industry whatsoever. We only need an additional 165 ppm to reach a doubling of pre-industrial CO2... -
SNRatio at 07:35 AM on 8 February 2011How We Know Recent Global Warming Is Not Natural
To me, Spencer's "challenge" indicates lack of insight in scientific processes. As long as we don't have complete descriptions, it is rather inappropriate to "rule out" anything. What we are doing, is looking for the models with the greatest explanative power relative to complexity. We also challenge these best explanations by testing the models in new situations, checking consistency in every possible way etc. It is rather futile to spend time "ruling out" possible explanations that are neither made explicit enough to be tested nor seem to be necessary. So, with Spencer's position, the challenge is, really, on him: To produce tests where the consensus models should be able to perform well, but they fail utterly. It is not enough to present special situations they have not been designed to model well, and where they therefore may fail considerably. Null hypotheses are usually picked as the "simplest" or "most natural" models, and hypothesis testing is mostly about rejecting the null hypothesis. Testing that is intended to provide support for the null hypothesis may be problematic, as the power of the test may be too low. Lots of denialist arguments rely on this, like "with this cold winter/high snow cover/seemingly falling temperatures/...., AGW must be minimal or non-existent". In the case of global warming, when the first null hypothesis of no warming has been rejected, the next step is of course to see if the effects established so far may explain the phenomena adequately. In this respect, Spencer's wishes are in a sense granted, in that "natural" factors, like solar irradiation, volcanism, aerosols and gases are taken into account. And so far, models which have included greenhouse gases have very often performed significantly better than models leaving them out. Thus, the initial null hypotheses of "no effect" are rejected, but this doesn't rule out the possibility that an entirely different modeling approach could lead to other results. But in a situation where the models work well, and rather easily include "new" phenomena, believing in entirely different explanations kicking out the well established factors looks like wishful thinking to me. -
mozart at 07:34 AM on 8 February 2011Global Warming and Cold Winters
Well I apologize for not providing a link, I assumed the herrera site was familiar to most serious students of the topic. But here you go: http://www.mherrera.org/temp.htm -
Global Warming and Cold Winters
mozart - We certainly don't need to double industrial energy use to double CO2 levels. They are increasing now at ~2.3ppm/year, an ongoing rate, any additional industrialization will increase that rate. At current rates (with no changes whatsoever in industry levels) we'll hit a doubling of CO2 over pre-industrial levels in ~70 years, and expected additional industrialization will make that time-frame shorter considerably shorter. Given your numbers, by 2050 we'll be increasing CO2 by an 80% higher rate, 4.15ppm/year. -
mozart at 07:25 AM on 8 February 2011Global Warming and Cold Winters
Now scadden you and I differ on the likely course of CO2. You refer me to a site with wildly varying estimates, most of which are hopelessly out of date following the Global near depression. No doubt those prognosticators that find their estimates within one standard deviation of the mean, feel they are being pretty "conservative". But read the US Energy Information Administrations stats on the growth of energy and you come up with the following: Energy usage from all sources will increase 48% by 2035, off a 2007 base. Taking that to 2011 and extrapolating to 2050....you get a linear trend number of 67%. Call it 80% to allow for compounding. So, even assuming we can't drive any efficiencies in carbon per unit of energy....we don't double carbon output from man made sources. And man made sources constitute a fraction of total CO2 production. Given this and the relatively small rise of 23% in CO2 since 1900, I find your confidence in these wildly differing estimates, bemusing to say the least. -
How We Know Recent Global Warming Is Not Natural
apiratelooksat50 - "I am not misrepresenting your argument..." You certainly misrepresented Dana in this post "Are you stating those forcings are not factors now?" and Dikran here "...are you of the position that only CO2 from human combustion of fossil fuels is the driving force?". Neither they nor anyone else I know of with reasonable knowledge of the subject has asserted that CO2 is the only forcing involved involved in climate. Just that it's the dominant one right now raising temperatures, which would otherwise have declined over the last 50 years. I think I'm fully justified in calling those posts strawman arguments. As to attributing current changes to "natural cycles", I suggest looking closely at the graph muoncounter provided. Current climate behavior (change rates) matches nothing seen in the Holocene or any previous interglacials, except perhaps the PETM event. -
Albatross at 07:15 AM on 8 February 2011How We Know Recent Global Warming Is Not Natural
Pirate @47, That is what people have been trying to tell you for ages now. That said, you forgot to include this part immediately below those questions: "Paleoclimatology offers help in answering each of these questions. Several of the paleoclimate studies reported in this web document have begun efforts to attribute past climate change to both natural and human causes, and to estimate how much of the current warming is due to humans (i.e., greenhouse warming). The best estimate is that about 50% of the observed global warming is due to greenhouse gas increases. The paleo record also tells us how much temperature change occurred in the past when carbon dioxide levels were different. Studies show that the 100 ppm reduction in carbon dioxide during the last glacial was accompanied by a 3°C cooling in the western tropical oceans. This amount of temperature change is consistent with the change predicted by numerical climate model simulations. Changes at higher latitudes were much larger and included the growth of large ice sheets." That was back in early 2009, and the contribution from GHGs is going to increase with time as GHG levels continue to escalate. Pirate are you suggesting that we should only take action if we have "complete" confidence? That would be absurd. The 95% confidence limits for expected climate sensitivity for doubling CO2 have been published (e.g., Annan and Hargreaves 2009) and calculated to lie between +1.5 and +4 K, with a most likely value of +3 K.
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