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shawnhet at 08:11 AM on 13 April 2011Solar Hockey Stick
??? Well, since you are clearly aware of the proposed GCR climate link, I don't know what you are asking for here. IIRC, cosmic ray counts have varied by ~30% over the last few hundred years where TSI has changed in the ballpark of 0.1%. If you have two quantities one that can vary by ~30% and one that can vary by 0.1% does it make sense to compare the effect of the two by multiplying them by a constant quantity as you do? Cheers, :)Moderator Response: [muoncounter] Cosmic rays are so popular among the denial crowd that they have their own thread (a personal favorite). No substantial correlation exists between cosmic ray counts and warming; the causal link (cloud formation) is also unsubstantiated. -
muoncounter at 08:08 AM on 13 April 2011Waste heat vs greenhouse warming
RSVP#358: " all energy delivered by all fossil fuels and nuclear reactors ... this energy is in backlog of whatever is considered equilibrium and therefore constitutes an excess which can only have been accumulating." Suppose for a moment that this is correct. We should expect to see 'hot spots' near places that deliver this energy. Indeed we do, when the fires are burning or the discharged coolant (water) is still hot -- I posted a false color IR of an Illinois power plant some time ago, on either this or the prior waste heat thread. But if this heat 'accumulates,' it must show up elsewhere in the environment. If RSVP is correct, it should eclipse other forcings. Luckily, we can test this idea: Belgium has an interesting website with thermal IR of a good chunk of the Antwerp area. Unfortunately its lacking in geographic references (and I don't read Belgian), but with Google Earth, you can find yourself. On the IR, just off the A12 highway in Stabroek, there is a peculiar rectangle of dark red (hot). Locating this point on GE, it is an old fort surrounded by a shallow water-filled ditch. There are several of these forts plainly visible in IR; Fort Merksem near the port of Antwerp is a beauty. They all have the same sort of shallow water-filled ditch (moat?). These are not industrial heat sources. They show up on the IR as hot because the water's low albedo absorbs solar energy. Conclusion: No evidence of accumulated industrial heat. Lots of evidence of solar-heated water. Now we must ask: Why doesn't the water cool off? -
daniel maris at 08:07 AM on 13 April 2011Has sea level rise accelerated since 1880?
I won't respond to the detail in view of the moderator's comment but I will say that I think you have a lot more to fear from population rise than temperature rise. -
mspelto at 08:07 AM on 13 April 2011Zebras? In Greenland? Really?
Adam's data of course ends in 2000. I did note in a paper I published that Jakobshavn was in approximate equilibrium with climate in the 1980's. It is the last decades warmth that has driven the amazing response of the glaciers that is the focus of this post. So the key climate data is that of the last decade. -
GFW at 07:53 AM on 13 April 2011Solar Hockey Stick
Anyway, if a reasonable estimate of the direct TSI impact is *less* than 10-20% of observed change in any of the warmings or coolings examined, with the assumed-to-be-proportional indirect effects bringing the impact *up* to 10-20%, then unless the error in assuming proportionality is many times the entire size of the estimate, there is no change to the conclusion. In concrete numbers, say in one warming the direct TSI accounts for 12% of the warming, and we're estimating indirect TSI = 0.25 direct TSI, so full TSI accounts for 15% of the warming. Sure, that 0.25 might actually vary a bit as a function of TSI rather than being constant, but unless it varies up to 10 times larger, it doesn't affect the conclusion that overall TSI is not the most important factor in the warming. -
Bob Lacatena at 07:45 AM on 13 April 2011Has sea level rise accelerated since 1880?
101, daniel maris,...costed value of additional crop yields...
I'm not sure where you get this, but in the long run, globally, everything I've seen says that crop yields will be down. Unlike much of the world, the USA is expected to benefit in the short term, as precipitation and temperature increases in the center of the continent are expected to be more mild, however, the southwest will eventually be hard hit by both drought and extreme temperature ranges, and the fact that climate zones move north does not necessarily translate into "let's just farm farther north." You need to take into account length of day, precipitation, quality of soil, irrigation sources, etc. And if the weather becomes more erratic, even the better areas may be subject to crop killing droughts as often as not. Changing the temperature of the planet also dramatically changes the distribution of water and precipitation patterns in not entirely predictable or useful ways. Crop yields may rise fractionally for a decade, maybe two, then things go way, way down. And it only gets worse if biofuels are one of the more serious solutions to getting away from fossil fuels (i.e. if we need to use productive land to produce fuel instead of food). Of course, that may not matter much if it pushes us into WW III by 2050 or so -- over food and arable land (the climate losers may not take kindly to the USA using its meager climate benefits to produce biofuels instead of helping to feed a starving world).Moderator Response: Everybody, please get back to the topic of this thread. -
dana1981 at 07:44 AM on 13 April 2011Solar Hockey Stick
Albatross - indeed, nice links there. Gerda - no, the other 80-90% were due to other factors, like natural variability and such. The solar feedbacks are included in the 10-20%. From Peru - we don't just provide author plus date, we also provide links to the papers themselves. Unfortunately, I forgot to do that in this case! I'll edit the article to include the link. Thanks for noticing that. -
From Peru at 07:41 AM on 13 April 2011Solar Hockey Stick
There is the bad habit of showing as a reference of a paper only the author plus the journal and the date, without inluding the most important information: the TITLE of the paper. This happen in a lot of publications and unfortunately also here. This is a problem because one has to try different combinations of the names of the authors plus the name of the journal plus the date(that often is only the year, without indicating the month and the day), and as a consecuence sometimes one finds not one, but a series of articles by the same authors. To help the readers of skepticalscience, here is the link: Evolution of the solar irradiance during the Holocene -
scaddenp at 07:40 AM on 13 April 2011Zebras? In Greenland? Really?
"If all of post 1970 warming was due to humans, then it would have meant that the warming that occurred on Greenland during that period would have also been caused by humans. Yet, as shown by all of the papers I provided you and by Dana's own graph, for those 30 years Greenland temperature remained below what it was 60 years ago. This clearly contradicts AGW." CO2 is not the only driver of climate Not that simple. -
littlerobbergirl at 07:38 AM on 13 April 2011Solar Hockey Stick
still 12th april here (just). happy anniversary yuri! possibly i have not understood any of this post but, does this mean the other 80 - 90% of historical warming/cooling was down to climate feedbacks in response to the small changes in solar irradiance? we really are stuffed if that's the case. but what about early anthropocene influence? lots of forest cleared, increases in population and domestic animals, in roman times, and especially in medieval period before the plagues (and a lot less after). but that's not too hopeful either, considering our current population and behavior. and how do we tease those two terrestrial factors apart? -
Albatross at 07:37 AM on 13 April 2011Solar Hockey Stick
Dana @17, "Not quite enough for another LIA!" Not even close. And you are in good company. The next ice age has been delayed indefinitely, also see Feulner and Rahmstorf (2010). -
scaddenp at 07:36 AM on 13 April 2011How I lived through a carbon tax and survived to tell the tale
I agree that #1 needs treaty but I think its easier to get than an emissions treaty. On 2/, well our previous government did just that. No new FF thermal unless you could deal with the emissions. It certainly spurred interest in clean coal and alternatives. A lot easier that designing a C&T without undesirable loopholes. US needs to deal with fundamental problem of lobby power. It's destroying your democracy. -
dana1981 at 07:34 AM on 13 April 2011Zebras? In Greenland? Really?
I think I'm arguing with a brick wall here. Adam, I'm looking at my calendar right now, and it tells me the year is 2011. So I'm having a hard time understanding why you're unwilling to consider Greenland temperatures after 2000. There's a word for that, we don't like to use it here, but it starts with the letter "d" and sounds like a river in Egypt. As for this claim:"If anthropogenic CO2 was the cause of 1994-2010 warming, then according to the theory, that period should have warmed faster, but it didn't."
As Daniel and I have explained several times, this is a logical fallacy, and a false statement. As Rob notes in #37, none of us have ever claimed that CO2 is the only factor impacting global temperatures, and certainly not local temperatures. I suggest you take some time to learn and understand the AGW theory before claiming you've disproven it. -
michael sweet at 07:34 AM on 13 April 2011How I lived through a carbon tax and survived to tell the tale
The paper that Dan linked here about a survey of economists supporting a carbon tax would be worth a thread by itself. Thanks for the heads up. -
dana1981 at 07:25 AM on 13 April 2011Solar Hockey Stick
shawnhet #18:"Since we can be pretty sure that most of the leading candidates for indirect effects do not vary linearly with TSI..."
Please substantiate this claim. -
shawnhet at 07:23 AM on 13 April 2011Solar Hockey Stick
Dana, again, your approach is only reasonable if 1.the indirect solar effects vary linearly with TSI or 2. they are essentially trivial. Since we can be pretty sure that most of the leading candidates for indirect effects do not vary linearly with TSI your position is de facto that you believe 2 to be true. Cheers, :) -
dana1981 at 07:22 AM on 13 April 2011Solar Hockey Stick
Something I didn't mention in the article - recently "skeptics" have claimed to be worried that a new Maunder Minimum (late 17th century) event would trigger another Little Ice Age type event. As shown in the article, this would cause on the order of 0.2°C cooling. Not quite enough for another LIA!
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Rob Honeycutt at 07:19 AM on 13 April 2011Zebras? In Greenland? Really?
Adam said... "for the past 70 years, as often pointed out by AGW believers, CO2 levels have skyrocketed. If anthropogenic CO2 was the cause of 1994-2010 warming, then according to the theory, that period should have warmed faster, but it didn't." Really? Is that what we say? I would modify that to say "if there were no other forcings on the climate system..." then yes, you'd be right. But no one claims that CO2 is the only mechanism that affect climate. We only say that CO2 is the biggest control knob. -
Bob Lacatena at 07:17 AM on 13 April 2011How I lived through a carbon tax and survived to tell the tale
174, scaddenp, On #1, absolutely, yes, I can't believe it even needs to be discussed... except for the political power of the FF industry, and other complexities in the issues, such as the fact that the issues are not that simple... if some tax breaks are taken away, the obvious business response would be to let American oil fields lie untapped and put more resources into tapping foreign oil, which many companies can do without paying US taxes and paying lower foreign tax rates. The net result would be the same oil production, lost American jobs, and a negative political fallout for the politicians that endorse it. Like most things, it's not as simple or as obvious as it sounds. On #2, you'd similarly have a lot of lobbies to fight through (coal miners, coal economy states, coal industry heavyweights, etc.). And again its not that simple. What if the new, cleaner (if not clean) coal plant that you want to prohibit is to be built so that they can shut down an old, inefficient and dirtier one? Do you force them to build nuclear instead? The reality is that we will never be able to turn any source of energy off like a tap. The economy is too complex and interdependent, and the infrastructure is too inflexible. That's why action needs to begin soon, in a variety of areas (changing that infrastructure, such as how power is delivered, how vehicles are fueled, etc.) We don't need dramatic solutions, so much as we need to begin concerted work on a variety of solutions, so that we have better options as things get worse. This is the whole reason for general solution tax mechanisms like cap-and-trade or fee-and-dividend. If you try to target specific items, that's the "communist, centralized economy" approach that tends to fail abysmally. There are always pitfalls that people didn't foresee, and there's no reason to be so single-mindedly focused, no matter how obvious the solution may seem to be. A broad brush attempt to try to make FF carry their full (including externalized) costs will lead instead to many different, but hopefully appropriate, solutions in different arenas, as is fitting in each case. -
dana1981 at 07:17 AM on 13 April 2011Solar Hockey Stick
Alexandre - I actually hadn't heard that particular myth before Sam mentioned it. You're right, it might make for an interesting post. Thanks for the suggestion. -
Riccardo at 07:17 AM on 13 April 2011Solar Hockey Stick
... and it can not explain a significant portion of the temperature variations during the last 2000 years, as clearly seen from fig. 2 and 3. -
muoncounter at 07:14 AM on 13 April 2011Zebras? In Greenland? Really?
Adam#34: "for the past 70 years, as often pointed out by AGW believers, CO2 levels have skyrocketed." If by 'skyrocketed,' you mean an increase of between 1 and 2.5 ppm per year. "If anthropogenic CO2 was the cause of 1994-2010 warming, then according to the theory, that period should have warmed faster," Apparently you are unfamiliar with the way that radiative forcing works. 'It should have warmed faster' ... than what? There are ample threads here, all with pointers to the relevant literature, explaining this process in detail. Look at the rate of temperature increase in the northern latitudes since 1970 or so, they are increasing pretty quickly: 0.3C per decade in Europe, 0.5C per decade in parts of Canada, close to 0.6C per decade farther north. There are ample threads here for that information as well. -
Albatross at 07:05 AM on 13 April 2011Solar Hockey Stick
This is beginning to be a case of 'anything but CO2' wishful thinking. Dana is right-- if certain predictor variables (e.g., solar parameters) are highly correlated with each other, and one is applying a multiple linear regression to explain the variance in a dependent variable (e.g., such as global surface air temperature), then one has to choose one of the correlated group of predictor variables. Interesting (problematic) thing about multiple regression is that as soon as one adds more variables the R^2 (variance explained) goes up, when in reality might not be explaining more of the variance in the dependent variable--that is why statisticians use the adjusted R^2 when using multiple parameters. And again, some caution, without a physical mechanism to explain a relationship, correlation does not imply causality. At the end of the day, solar can not explain a significant portion observed warming since circa 1880, and this is especially true for the recent warming. Pretty sad that so many people continue to believe that solar is the primary cause. -
Alexandre at 07:02 AM on 13 April 2011Solar Hockey Stick
Dana #8 I meant that alledged unreliability of the ice cores due to supposed contamination before proper compression. I think that's what Sam's claim is about, and also the excuse Ernst Beck used for relying on chemical measurements on his below-standard E&E paper, with this CO2 time series:
Richard Alley metions the ice core reliability on his Biggest Control Knob lecture, and I'm sure there are some early papers to back this up. I thought it could be a good subject.
Well, I'm going way off topic here. Just didn't know where else to suggest it. Feel free to delete this after considering the suggestion.
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Rob Honeycutt at 07:01 AM on 13 April 2011Zebras? In Greenland? Really?
Adam... Surely you jest. You are claiming that his published research is showing something completely different that what is expressed by his opinion? That's quite an alarming claim. -
dana1981 at 06:55 AM on 13 April 2011Solar Hockey Stick
I didn't move any goalposts. The article clearly states "conservatively estimate". These are all estimates, but my approach was a mathematically reasonable way to incorporate indirect effects. And it's not sufficient to claim that some solar effect varies by 10% over some timeframe. You have to have a mechanism whereby this solar effect is impacting the global climate. You know, that damn causation thing again. -
Adam at 06:52 AM on 13 April 2011Zebras? In Greenland? Really?
"As both Dana and I have amply shown, current levels of warming in Greenland exceed those measured in the early part of the previous century. I can appreciate your not wanting to accept that, but that's the reality of the data." Daniel, I accept that 2010 was unusually warm for Greenland's climate (which was the big temp spike in Dana's graph), but as Dana's graph also showed, for all of pre-21st century climate, Greenland remained warmer 60 years. Now as shown by the papers I provided you (one of which was authored by two AGW scientists) Throughout the 20th century (1900-2000) Greenland was warmer in the 1930's. You have not answered what I have brought up. If all of post 1970 warming was due to humans, then it would have meant that the warming that occurred on Greenland during that period would have also been caused by humans. Yet, as shown by all of the papers I provided you and by Dana's own graph, for those 30 years Greenland temperature remained below what it was 60 years ago. This clearly contradicts AGW. "It's true that the rate of warming 1916-1932 was a bit faster than the rate 1994-2010, but so what?" Dana, for the past 70 years, as often pointed out by AGW believers, CO2 levels have skyrocketed. If anthropogenic CO2 was the cause of 1994-2010 warming, then according to the theory, that period should have warmed faster, but it didn't. Daniel, I am aware of all the policies at skeptical science. This may be my first time commenting, but I have been aware of this website for months. You do not need to tell me things I already know. Rob Honeycutt, Jason Box's opinion did not reflect on the data presented in his papers. Whether he believes what is in the IPCC's report is his choice, and has got nothing to do with what he presented in his papers. -
daniel maris at 06:48 AM on 13 April 2011A Plan for 100% Renewable Energy by 2050
I'm beginning to think that we need to think of using solar and wind to create methane, as a way of fast tracking to 100% renewables. (The methane is made from water and air). Here's an interesting recent article on Caltech research. http://www.abc.net.au/rn/scienceshow/stories/2011/3155436.htm Methane has lots of advantages: we already have transport and transfer networks for this gas and we already have the generators in place. We can make the methane in those sunny desert zones where solar energy works best. Then we avoid the need for huge Desertec-style grid schemes, that in any case are vulnerable to terrorist and other disruption. -
shawnhet at 06:37 AM on 13 April 2011Solar Hockey Stick
Dana, I think you are moving the goalposts here, big time ;). We've gone from a mathematically identical relationship to a reasonable approximation. IAC, none of this changes the fact that there are many changes in solar effects that vary more widely than TSI. If TSI changes by .1% and another proxy changes by 10% over a certain period, we cannot use your framework to meaningfully calculate the total solar effect on climate. Cheers, :) -
Rob Honeycutt at 06:27 AM on 13 April 2011Zebras? In Greenland? Really?
Adam... I'm very curious how you can cite Dr Box in one post and then turn around and dismiss his conclusions in another post just 12 minutes later. -
daniel maris at 06:25 AM on 13 April 2011Has sea level rise accelerated since 1880?
Scaddenp - I think the point is that Stern does not cost positive effects in the same way he costs harmful effects. I didn't see any evidence that Stern had (a) costed value of additional crop yields and (b) incorporated such costings into the overall cost-benefit analysis. Tom Curtis - You're wrong. We're sinking in the South where I live(Scotland is on the up). But even so I have not noticed any serious effects. Of course, there must be effects and we must be reacting to them...I am just pointing out they haven't been catastrophic. -
dana1981 at 06:21 AM on 13 April 2011Solar Hockey Stick
Ah but shawnhet, as you already noted, various solar attributes correlate well with each other. TSI and solar magnetic field (which impacts galactic cosmic ray flux on Earth) are strongly correlated, for example. So I think lumping them together is a reasonable approximation. -
Daniel Bailey at 06:19 AM on 13 April 2011Zebras? In Greenland? Really?
Adam: You're new to Skeptical Science and how normal business is conducted here can be a bit confusing for the newcomer. That's why we recommend that Newcomers, Start Here and then learn The Big Picture. I also recommend watching this video on why CO2 is the biggest climate control knob in Earth's history. Further general questions can usually be be answered by first using the Search function in the upper left of every Skeptical Science page to see if there is already a post on it (odds are, there is). If you still have questions, use the Search function located in the upper left of every page here at Skeptical Science and post your question on the most pertinent thread. Remember to frame your questions in compliance with the Comments Policy and lastly, to use the Preview function below the comment box to ensure that any html tags you're using work properly. The Yooper -
scaddenp at 06:19 AM on 13 April 2011How I lived through a carbon tax and survived to tell the tale
I'd still love to see the results of doing 2 simple things before worrying about tax or ETS. 1/ Kill all forms of subsidy on FF. I just cant believe you have the right wing supporting subsidies in the US where its supposedly the home of capitalism. Evidence of corrupt government. 2/ Simply ban any new coal-fired generation. That concentrates the mind of energy sector. Now let capitalism do its thing. -
shawnhet at 06:18 AM on 13 April 2011Solar Hockey Stick
Dana, just because one watt of forcing *might* equal another watt of forcing does not mean that the amount of indirect forcing changes linearly with the amount of direct forcing which is what your formulation requires. BTW, since you bring it up, you can find plenty of evidence that all forcings are not equal at all times if you want(compare the bottom curve with the temperature ones). http://en.wikipedia.org/wiki/File:Vostok_420ky_4curves_insolation.jpg Cheers, :) -
dana1981 at 06:16 AM on 13 April 2011Zebras? In Greenland? Really?
Adam, there is a difference between rate and absolute temperature. Box's data clearly shows Greenland is currently warmer than in 1930. It's true that the rate of warming 1916-1932 was a bit faster than the rate 1994-2010, but so what? There are no opinions presented here. Box clearly referenced the IPCC AR4 in his anthropogenic attribution statement. If you want evidence, go read the IPCC report. -
Daniel Bailey at 06:08 AM on 13 April 2011Zebras? In Greenland? Really?
@ Adam Again, the thrust of this thread is about the various responses of the different types of Greenland ice sheet outlet glaciers to the documented warming of the globe (of which Greenland is but part). As both Dana and I have amply shown, current levels of warming in Greenland exceed those measured in the early part of the previous century. I can appreciate your not wanting to accept that, but that's the reality of the data. The gist of your position is: 1. It was warmer than now previous 2. It's not CO2 causing the warming that is not happened (the logical fallacy that Dana spoke of) #1 has already been demonstrated to be false. For #2, you have multiple issues. Search for "It's Not Us" or one of the many myriad other skeptic favorite toys listed under the Taxonomy listing of skeptic arguments to further your knowledge. Unless you wish to discuss something actually pertaining to the topic of this particular thread, your positions are best discussed where directed previously (and as such are off-topic here). The Yooper -
dana1981 at 06:07 AM on 13 April 2011Solar Hockey Stick
shawnhet - a forcing is a forcing is a forcing. They don't operate differently except for the slight variation in the climate sensitivity parameter for the various forcings. Mathematically I've got the possibility of indirect effects accounted for. Alexandre - we do have "How reliable are CO2 measurements?". Sam's comments are of course irrelevant here, since there was no reference to ice core measurements. -
Alexandre at 05:37 AM on 13 April 2011Solar Hockey Stick
About SkepticalSam's claims: does SkS already have a post on ice core studies? I tried to find something on the arguments and did not find any. It would cover some "skeptic" arguments like Ernst Beck's... wouldn't it be worth a post?Moderator Response: [muoncounter] Search 'ice core'. Also look at 'co2 lag'. -
shawnhet at 05:33 AM on 13 April 2011Solar Hockey Stick
Dana, the point is, that there is a difference btw an indirect effect and simply multiplying the direct effect by some factor. An indirect effect(whatever it is) will operate how the indirect effect operates - not how TSI operates. The two things are only mathematically identical if you assume that they operate the same way(which there is no reason to assume). Cheers, :) -
Adam at 05:28 AM on 13 April 2011Zebras? In Greenland? Really?
Dana all I am asking is that you simply present proper empirical evidence that humans are the cause of the Greenland warming and glacial melt described in this article. I'm not being unreasonable. The hypothesis of AGW means that post 1980 Greenland warming was caused by humans. I have not seen any empirical evidence for this claim. All I am asking is that you provide it.Moderator Response: Discussion of the anthropogenic attribution of the warming observed in Greenland is off-topic for this post. Please follow the directions given in the next comment by Daniel. Thanks! -
dana1981 at 05:27 AM on 13 April 2011Solar Hockey Stick
shawnhet - I'm not saying the TSI sensitivity is high. I'm effectively hedging my bets by including indirect solar effects as a feedback encompassed in the solar climate sensitivity parameter. Now, you can say that I'm not inflating the sensitivity enough to account for the full effects of these indirect factors (which I would disagree with - again, see the cosmic ray link above), but mathematically, there's really no difference. To account for the indirect effects, either you inflate the senstivity or you inflate the forcing. The mathematical result is the same either way. My calculation is really no different than assuming there's an indirect solar forcing ~20% as large as the TSI forcing. -
Adam at 05:25 AM on 13 April 2011Zebras? In Greenland? Really?
Dana personal opinions have know meaning in science. Jason Box's personal beliefs do not effect the actual data presented in his papers; that Greenland was warmer 60 years ago.Moderator Response: Dr. Box was quoting the IPCC and is thus not expressing a personal opinion. -
Adam at 05:24 AM on 13 April 2011Zebras? In Greenland? Really?
Dana, the 2010 spike in Greenland temperature is most likely due to el nino, as it was with the rest of the globe. Dana, as your own graph shows, for all of pre-21st century climate Greenland was warmer from 1920 to 1940. Now anthropogenic greenhouse gases supposedly started having a major effect at around 1975. Therefore, the theory means that post 1975, Greenland should have been experiencing anthropogenic global warming. Yet, as your own graph shows, that for the 30 years of warming (1970 to 2000) that was meant to be caused by humans, Greenland had not exceeded it's previous period of warming. Once again, as your own graph shows, the 1920 to 1940 warming occurred at a much faster rate than the 1980 to 2000 warming. -
dana1981 at 05:21 AM on 13 April 2011Zebras? In Greenland? Really?
It's also worth quoting Dr. Box on the causes of Greenland warming (emphasis mine):"The recent (post-1994) warming, is attributable to: 1) a growing absence of sulfate cooling because there has not been a major volcanic eruption since 1991; 2) recent warming phase of AMO; 3) an apparent reversal of the global dimming trend; and 4) ongoing and intensifying anthropogenic global warming (AWG), the elephant in the room, owing to a dominance of enhanced greenhouse effect despite other anthropogenic cooling factors such as aerosols and contrails (IPCC, 2007). The primary factor responsible for the warming trend is very likely to be AWG (IPCC, 2007)."
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Adam at 05:16 AM on 13 April 2011Zebras? In Greenland? Really?
"This data on Greenland is an example of that data, which supports the AGW conclusion. Why does all the data point the same way?" Michael could you please explain that statement? Could you explain how data from Greenland support AGW? -
dana1981 at 05:14 AM on 13 April 2011Zebras? In Greenland? Really?
Adam - Greenland doesn't exist in a bubble. I have a hard time understanding how you can argue that the increased greenhouse effect, which we know is warming the planet, isn't warming Greenland. It's true that there was a significant warming event in Greenland in the early 20th century, in which human greenhouse gas emissions only played a small role, but the existence of a previous natural warming doesn't mean that the current warming can't be anthropogenic. That's a logical fallacy. By the way, your Jones and Briffa reference only contained Greenland temperature data up to 2000. Here's the up-to-date data from Jaxon Box's website.
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Adam at 05:13 AM on 13 April 2011Zebras? In Greenland? Really?
Now Daniel, the point of your article is that Greenland glaciers are melting rapidly due to global warming. But this is only evidence of warming and not anthropogenic warming. I have not seen any credible evidence that the current Greenland warming is caused by humans. It is very likely that the same amount of melting you describe in your article also happened 60 years ago. Dana is misunderstanding what I am saying. I' m not saying it's warmed naturally before, so it's current warming must be natural. I am just saying that the melting of glaciers that you describe is well within the natural variability of Greenland's climate, and is not likely to be caused by CO2. Really the only clear evidence that humans have got anything to do with post 1980 greenland warming is computer models, and as shown by Polyakov's 2002 paper, they have failed to replicate the current Arctic climate. I also suggest you read this paper, which supports the same conclusion that the current Greenland climate is not unprecedented: "Greenland ice sheet surface air temperature variability: 1840-2007” by Jason Box et al, published in the 'Journal of Climate (2009) http://polarmet.osu.edu/PolarMet/PMGFulldocs/box_yang_jc_2009.pdf Look, when looking back at past temperature data for Greenland, you can see that there is nothing unusual or unprecedented about the past 20 years of warming. It is very difficult to detect any anthropogenic signal in Greenland's climate. A lot of the temperature and ice variations are very hard to be explained by CO2. I think that based on what we know about Greenland's climate, and it's history, the most plausible explanation is that it's current climatic changes are of natural causation. -
shawnhet at 05:13 AM on 13 April 2011Solar Hockey Stick
Ok, but there is a difference btw saying that the TSI sensitivity is high and saying that some other factor related to solar activity can cause changes in climate. As such, simply inflating the solar climate-sensitivity doesn't reflect the wide and various correlations btw climate and solar proxies very well. Cheers, :) -
Daniel Bailey at 05:13 AM on 13 April 2011Zebras? In Greenland? Really?
@ Adam Look again at the graphs I generated above on the polar projections for the Arctic, both for the periods covered by Chylek 2006 and the most recent 10 year trend. In both, Greenland is warmer in the recent interval than the earlier. It is the lack of data from the earlier timeframe that keeps us from concluding with very high confidence that the entirety of Greenland is now the warmest in the instrumental era. Your comments about CO2 levels relative to temperatures quite frankly betray a lack of understanding of the time lags involved in order for temperature equilibria from CO2 forcing to be realized. As that is off-topic here, you can find many more appropriate threads than this to further your knowledge. The thrust of your position, that CO2 is not driving Greenland (or any other) climate change, is similarly off-topic here. The Yooper
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