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The contradictory nature of global warming skepticism
Baz > However, you should recognise that I came on here looking for an answer from those present on what they would accept as 'the' period to conclude that the AGW hypothesis may be false. We're dealing with statistics here, so there is not going to be a single hard number. In any case, you've gotten your answer multiple times: 15 years to establish a bare minimum of statistical significance, and enough to perhaps cast doubt, 25-30 years to establish a long term trend with high confidence. What more do you want? -
The contradictory nature of global warming skepticism
Daniel, your ra-ra support of archiesteel's "3-year trend" is mis-placed, as it shows that your question to me of what was I trying to achieve now holds no credibility. -
archiesteel at 05:16 AM on 16 September 2010The contradictory nature of global warming skepticism
@Baz Oh, and before you point out Berenyi Peter's comments in that thread, you should know he refuses to address the accusations of scientific fraud leveled at him, accusations that put his entire credibility at risk. If you are truly objective, and value actual research over BP's cherry-picking antics, then you have no real option but to acknowledge that oceans have continued to accumulate heat over the past decade, and have increasingly done so over the past three years. -
citizenschallenge at 05:14 AM on 16 September 2010The Pacific Decadal Oscillation and global warming
I always thought > but never see anything on it - that the PDO is related with Pacific Ocean water mixing dynamics. Can anyone speak to that? -
archiesteel at 05:12 AM on 16 September 2010The contradictory nature of global warming skepticism
@Baz: "Perhaps you would feel more at ease if we looked at ocean temps instead. I'm sure you understand that we could talk about them, and that I may be on safer ground (given the lack of heat content over the past few years)." But the oceans *have* been warming over the past few years! Here is the article on SkSc Also, you haven't told me what you think about the warming "restarting" with a vengeance in mid-2007? "Daniel, I certainly don't have the time for pointless debate, and that's exactly why some on here haven't had their 'questions' answered." How convenient. -
The contradictory nature of global warming skepticism
Paul Daniel Ash. There was only one question mark in your 177, and I responded. Do you want to debate rising ocean heat content, or falling ocean heat content? Or do you want to debate the fact that it's still unclear, and that it may falsify the AGW hypothesis long before surface temperatures do? -
The contradictory nature of global warming skepticism
Daniel Bailey. Thank you for your post. Yes, of course I understand the importance of using long time spans for revealing trends in surface & sea temperature change. However, you should recognise that I came on here looking for an answer from those present on what they would accept as 'the' period to conclude that the AGW hypothesis may be false. Perhaps you would feel more at ease if we looked at ocean temps instead. I'm sure you understand that we could talk about them, and that I may be on safer ground (given the lack of heat content over the past few years). However, it is the surface & sea temps that politicians and journalists use, so I simply wanted to pose that question. I could equally have said, 'For how long should we observe no increase (or even decrease) in ocean heat content before we conclude that the AGW hypothesis is false?' I assume you're referring to realclimate when you ask about the contributions of publishing professionals - is that correct? Having read the site on many ocassions then I conclude it's not worthy. However, if you are referring to something particular I've said, then please say precisely. In short, I certainly require to learn more, but I feel there are far too many closed minds in both camps. The subject of AGW is often likened to Creationism. However, there are totally closed minds in Creationism, again on both sides, but neither is provable. Of course, Creationism is a nonsense, and not worthy debating. But with AGW a period of time should 'prove' the issue one way or the other. What I've been exploring here is that time period. But as I said, we could look at the heat store (oceans) rather than the time-lagged result (atmosphere) and ask ourselves if heat is being accumulated. Daniel, I certainly don't have the time for pointless debate, and that's exactly why some on here haven't had their 'questions' answered. I find this sort of poking extremely tiresome, and surely for another forum entirely. -
The contradictory nature of global warming skepticism
Baz - In regards to statistical significance, you might benefit from looking at the Phil Jones says no global warming since 1995 thread. There are some useful discussions there on what timeframe is appropriate for statistical significance, and what time periods are usable for drawing conclusions. As headlined in a British paper early this year, Phil Jones (climatologist) stated that the warming since 1995 was not statistically significant. By this he pointed out that the statistical chance of the null hypothesis (no warming) was at 8% - it should be under 5% for the 95% confidence generally used in statistical significance tests. Given the noise (weather, yearly variations) in the temperature trends, 30 years is considered the appropriate period, not 15. And the global warming trend from 1980 to 2009 (just over 1 degree Fahrenheit) is statistically significant at the 99.9999 percent level. That is to say, given the data, there is only a 0.0001 % chance that it wasn't warming over that 30-year time frame; that the resulting data was due to a noisy but not trending signal. You can certainly make claims of personal belief from 10 years of data - that's up to you. However, you cannot claim scientific evidence, statistical significance, from such a short time frame. The numbers don't support it. -
Johngee at 05:00 AM on 16 September 2010It's not bad
All taken on board Dan. Watched the lecture. Very good indeed! I'd like to comment on Monckton/congress thing myself but everytime I try my voice gets lost in a scream of discombobulation. -
The contradictory nature of global warming skepticism
@Baz, Multiple posters have pointed out that the HadCRUT data has been shown via independent analysis to be underestimating warming over the last decade due to low arctic coverage. So not only do you have only one temperature series out of many (not just the GISS) that even barely suggests flattening temperatures, but in addition that temperature series has been shown to be flawed. According to this analysis, it is irrelevant at this point whether a 10 year flattening is statistically significant or not, because such a flattening did not happen. This is a critical issue for your argument, since you've decided to rest your entire position on this single data set. Is it any wonder you've been accused of cherry picking? How exactly do you justify using this single flawed data set while ignoring all others? Note that the press release I linked to above came from the Met Office, the parent organization of the Hadley Centre. The Met Office clearly agrees that their own data is incomplete. How do you justify putting your trust in the Hadley Centre when their data shows flattening temperatures, but dismissing them when they claim that same warming was underestimated? What do you call this if not cherry picking? -
Chris Colose at 04:29 AM on 16 September 2010Why positive feedback doesn't necessarily lead to runaway warming
Tim The Tool Man, I'll try another way. Imagine you are looking down at the planet from outer space and you are wearing some sort of glasses which allow you to see in the infrared. Furthermore, you also have the ability to distinguish between different wavelengths of infrared radiation. Just for the thought experiment we'll ignore water vapor and other greenhouse gases and focus on CO2. What you'll see if the planet has no greenhouse gases (from space) is all of the infrared radiation emanating from the surface and being received by your glasses. For a no greenhouse atmosphere, this radiation will roughly correspond to the surface temperature (as given by the Stefan-Boltzmann law). Now if we bump up the CO2 amount to, say, 10 ppmv then from space still you will see a lot of Earth's radiation from space coming up from the surface. These are the window regions where CO2 is a poor absorber. But in regions where CO2 absorbs strongly, you will see some radiation coming from near the top of the atmosphere. It is much colder here and so the emission you are seeing is "weaker" than the surface radiation. The dominant CO2 feature for Earth is actually the 15 micron region, not 4 (The 4-micron region is actually a stronger band, but this really can't be that crucial because Earth's Planck-weighted emission at this wavelength is very small, although it matters more for a planet like Venus). If you keep the temperature fixed, the Earth is now emitting less radiation to space, because now the OLR is the original minus the "bite" in the spectrum due to the CO2 band. The Earth's goal is radiative balance, and so the only way to get the original back (to compensate for the loss due to CO2) is to increase the temperature, which increases the whole area under the curve of a Planck radiation plot. This means the decrease in emission from the 15 micron spectral flux is compensated by an increase from window regions such as at 10 microns. This spectral selectivity is also key to understanding stratospheric cooling by the way. Eventually (at relatively low concentrations) at the center of the CO2 band, the emission from space is coming from as high as you can really get. In fact, at current concentrations of CO2 near the band center right at 15 microns, your glasses are seeing emission from the lower stratosphere. So, generally the OLR is greatest for regions of a warm surface that is overlaid by a dry, cloudless atmosphere and least in the polar regions or regions where you have cold cloud tops. Outside of the 15 micron center (but still within where CO2 strongly absorbs, at the edges) you are seeing emission somewhere between the surface and tropopause. This height of emission will clearly increase as you add more and more CO2. This "height level of emission" is what neal is referring to as the photosphere (it's not generally a term you'll see in the literature or conversation, but I don't suppose there's anything wrong with it...it's usually applied to the outer layer of the sun when climatologists talk). The key to the saturation arguments out there are that there's always more absorption waiting out in these wings, and depending on the wavelength you can always have an impact by increasing the height of emission to space, which reduces the OLR for a given temperature. So if you're doing government work and don't need super-fancy science you can model the emission from a planet with a greenhouse effect as something like T to the 3.9th power or whatever. To summarize, the best way to think about the greenhouse effect without getting into all the subtle spectral details is that for a given temperature, the outgoing radiation to space is reduced when you add GHGs. So if you don't change the incoming part of the radiation from the sun you need to warm up by a certain amount to get back in that radiative equilibrium. Note that a lot of the basic internet descriptions focus on the enhanced downward infrared emission to the surface but this is not really a good way to think about it because it's not necessarily inevitable more CO2 will directly increase the downward emission (like if you have a lot of water vapor in the boundary layer so it's already a blackbody at a given temperature) so most of the increased downward emission will actually come from increased temperature. Then, the surface energy budget is also linked to evaporation and other fluxes, so the enhanced CO2 problem is really a top of atmosphere centric focus. I've done a more complete post on this here (and if neal wants help with his future guest post I will be glad to!) -
werecow at 03:36 AM on 16 September 2010Does more extreme rainfall mean more flooding? Answer: Not always
Very interesting post and topic. I look forward to future installments. -
Daniel Bailey at 03:19 AM on 16 September 2010The contradictory nature of global warming skepticism
Re: archiesteel (200) Nice point with that three-year trend. Ouch. The Yooper -
archiesteel at 03:13 AM on 16 September 2010The contradictory nature of global warming skepticism
@Baz: one last point, since you seem not to care about statistical significance. What do you think about the fact that there has been a tremendous warming increase for the past three years? Isn't that enough to tell you that global warming has restarted? -
Paul Daniel Ash at 03:11 AM on 16 September 2010The contradictory nature of global warming skepticism
All that I require is that global temperatures resume - that's it! You'll forgive me if I find this an unserious reply. As Daniel Bailey says above "The explanation that is best representative of the whole of the data is most credible." Can you explain what you find lacking in this approach? Any response to the other information in my comment? -
archiesteel at 03:07 AM on 16 September 2010The contradictory nature of global warming skepticism
@Baz: Daniel Bailey explained it better that I could. Personally, it seems clear to me you are not interested in a rational exchange of ideas since you continue to estimate the slower warming in the last 10 years is significant enough to warrant you "changing your mind," when from a statistical standpoint it clearly isn't. *You* don't get to decide what is statistically significant. You've made your case. People have provided counter-arguments. You've ignored the counter-arguments, restating your initial position. In other words, you are not here to learn, but to push your opinion. This isn't the right forum for this. Please go repeat your debunked claims elsewhere, thanks. -
archiesteel at 03:01 AM on 16 September 2010The contradictory nature of global warming skepticism
@Eric: "The populations you listed as not threatened by hunting (e.g Baffin Bay) clearly are." Actually, *only* the Baffin Bay population is cited in the study as being over-harvested. Meanwhile, Taylor claims there is no decline, and that the population as a whole is not over-hunted (thereby destroying your argument): "For the most part, polar bear populations have increased or remained stable under the current regulatory regime. Reductions to some populations due to over-hunting were identified, and these populations appear to have recovered or are recovering." So Taylor argues there is no reduction, which puts him at odds with both the Norwegian researchers (who claim populations are going down due mainly to CC) and you (who claim populations are decreasing due to over-hunting). This is exactly what I mean by cherry-picking: the only reason you'll cite Taylor is not because you agree his methodology is sound, but simply because you can mine his letter for a single instance where he appears to support your position (when in fact he doesn't, as the Baffin population is the only one he mentions suffered from over-harvesting). So, again, you have utterly failed to indicate that over-harvesting is the main factor responsible for the decline in polar bear numbers. Sorry. -
ClimateWatcher at 03:01 AM on 16 September 2010Why positive feedback doesn't necessarily lead to runaway warming
>"I really can't make sense of the rest of your >argumentation, no one else seems to be paying >much attention, and it clearly does not derive from >the relevant scientific literature so I'm just going to >take it as an ill-supported opinion and leave it at >that." If you have a specific question, I will gladly answer it. >For those who can't access this in press article, >this is the abstract: [re "Dessler and Davis in JGR"] Thanks for the link. This paper does provide some evidence of alternate humidity estimations that indicate increasing trends in water vapor aloft. That differes from the trends than the NCEP analysis, the ICCSP analysis, and the NVAP analysis: http://www.google.com/url?sa=t&source=web&cd=6&ved=0CC0QFjAF&url=http%3A%2F%2Fams.confex.com%2Fams%2Fpdfpapers%2F84927.pdf&rct=j&q=nvap%20paper%20von%20der%20haar%20water%20vapor&ei=x_SQTKf8M4OesQOv0cGyDg&usg=AFQjCNGSAZn3mjAW50coTgiXDs1bVnC4VQ&cad=rja The exceptions I would take to the paper are: 1. The focus on El Nino fluctuation to validate long term variation is not relevant - El Nino is a known internal DYNAMIC variation. It could easily be that the DYNAMICs which change the temperature also change the humidity and not the thermodynamics. In other words temperature and humidity are both forced by dynamic changes and are just co-variants. 2. The differing periods of the various analyses. 3. The analysis which indicates the greatest increases in humidity, the MERRA, is the high outlier, with the greatest variance from not just the NCEP, but the JRA as well. That doesn't mean it is not correct, but it bears watching. 4. The statement: "And finally, we point out that there exists no theoretical support for having a positive short-term water vapor feedback and a negative long-term one." I take this as saying: The observations must be wrong because they don't match the theory. -
Daniel Bailey at 02:58 AM on 16 September 2010The contradictory nature of global warming skepticism
Re: Baz (198, et al) I am on record as according you time to present your case, backed by references, before any label-attachments are made to your name. You haven't helped me out much. You cite one data source (HadCRU) which has the known weakness of omitting the Arctic, where other temperature series reflect the significant warming there. To form an opinion based on partial data doesn't reflect well on credibility. Hence some calling you out on a "cherry pick". The explanation that is best representative of the whole of the data is most credible. You also need to understand that, when dealing with noisy datasets such as temperature anomalies, short time series (5, 10, 15, 20 years) simply fail to achieve statistical significance relative to time series' of greater than 30 years or more length. The bare minimum, under theoretical optimum low-noise conditions, to achieve significance significance is 15 years (Tamino did a post on this some time back). The scientific consensus for significance in temperature changes is 30 years or more of data. Look it up. Help me out here and show you understand this much. No one here wants to see anyone come here and "not get it". We're here to help, that's why we try very hard to understand (we each have differing abilities in communication skillsets as well). This site is about outreach. You also state that you don't value the contributions of publishing professionals in the field. Help me understand, why are you here if not to either:1. Increase your knowledge on the subject Or to 2. Waste our time with pointless debate?
Let me know which. If you choose #1, I'm here to help. The Yooper -
Alexandre at 02:48 AM on 16 September 2010The Pacific Decadal Oscillation and global warming
Here's a proxy based reconstraction of the PDO over the last thousand years. The correlation between global temps and PDO is not there in the last century, and it's not there in the last millennium. McDonald & Case 2005 Variations in the PDO over the pas millenium -
Scrooge at 02:41 AM on 16 September 2010The Pacific Decadal Oscillation and global warming
Very clear and easily understood post. What speaks volumes is the cool phase being caused by warm temps in the north. Something I didn't realise but makes perfect sense even to a layman like myself. For 2 the South Florida Regional Planning Council is studying that with a grant from I think the EPA -
Daniel Bailey at 02:31 AM on 16 September 2010Video update on Arctic sea ice in 2010
Re: Berényi Péter (41)"As you can see the ice is less than a foot thick (in March!). It can't be multi-year ice, can it?"
Back then the subs circled to find iced-over leads to break through. Attempting to surface through the 10-20' standard thicknesses of the multi-year ice may have exceeded the design tolerances of their construction, so it wasn't an advisable risk. An attempt had been made by the Skate to surface at the pole a year earlier, in 1958, but had to settle for a lead 40 miles from the pole. While your picture is of the Skate in 1959 in the Arctic, read the crew description of the weather that day at the pole in my earlier comment (34 above). It is likely taken at another location on another day on that selfsame trip. While there would've been some light at or near the pole even though the first sunrise of the year came 2 days later, the level of blue in the sky implies a more southerly locale. For comparison purposes, an example of artic sunset (low light-level conditions). The Yooper -
The contradictory nature of global warming skepticism
scaddenp 178. I don't value either of them! -
The contradictory nature of global warming skepticism
"Troll", "Strawman", and "Cherry-picking" so far. Oh dear! Now I know this site is better than that, because I've been reading it. Please people, I may frustrate you because I don't know as much as you, and I may fail to see your point, and I'm on the border of scepticism, but please try and not trot out the same tired old forum cliches. I won't answer your 'question' if you cannot write in a polite manner without using hackneyed phrases. -
The contradictory nature of global warming skepticism
VeryTallGuy. Can you spot your own error? I was referring to the last 10 years temp as being remarkably stable. I read the (very) few answers I got from those here on what THEY believe is a reasonable period to show that AGW is 'not a problem'/'does not exist to any great degree'. It was THAT which is 15-20 years. You may have to read all the contributions again! -
The contradictory nature of global warming skepticism
kdkd 188. You say you posed a previous question. I clicked on that link of yours and the only question mark was against a sentence where you were 'wondering' something. If you have a question then please pose it. As you'll see going right back here, if there was a question presented in a polite way then I most likely answered it. If it was smart-assed, then I did not. Some people just like to read their own words, rather than engage in a worthy debate. -
The contradictory nature of global warming skepticism
Ann, see above. -
Doug Bostrom at 02:14 AM on 16 September 2010The Pacific Decadal Oscillation and global warming
Huntjanin there are some Florida-specific articles cited in the comments thread at this article on Skeptical Science. See in particular Climate Change in Coastal Areas in Florida: Sea Level Rise Estimation and Economic Analysis to Year 2080 Back on topic... -
The contradictory nature of global warming skepticism
Paul Daniel Ashe (177) you ask: "What evidence would you find convincing of a human fingerprint on global climate change?" This may surprise you, though it won't if you've been reading my replies... Actually very little evidence. It's not so much of a "human fingerprint" as whether or not (even if we are causing it) that we need to be worried. I'm not convinced that the climate system will roll over at our emissions. All that I require is that global temperatures resume - that's it! As I said above, HadCRUt's last 10 years: 0.40 0.46 0.47 0.44 0.48 0.42 0.40 0.32 0.44 0.49? (2010) ...for me shows that we aren't getting worrying positive feedbacks. However, if those temperatures (that we were getting in the late 1990s) resume then I'll be back on board. As it stands I see no reason to worry. If heat is being absorbed by the oceans then we won't have to wait long. But if the warmth we have witnessed is nothing special, has happened recently before, is checked by the climate system, or is caused by ocean current patterns - then we have nothing to worry about. -
Albatross at 02:04 AM on 16 September 2010Video update on Arctic sea ice in 2010
Rob @42, the image in question was in all likelihood taken in a frozen lead. If you look in the background (LHS top) you can see pressure ridges. Regardless, why would they try and break through surrounding ice that was say 5 ft or more thick when they could break through this relatively thin ice? I have a hypothesis as to why people post these images-- look how effective the photos from surfacestations.org have been in confusing and sowing the seed of doubt in people's minds, not to mention distracting them from the very real and much larger issue/s. -
Rob Honeycutt at 02:03 AM on 16 September 2010Video update on Arctic sea ice in 2010
BP... I think Alden makes a very good case here of how single data points can confuse an issue. I realize he is not talking about the ice 60 years ago but the point he makes at slide 7 really drives home why looking at overall trends are so important. -
Rob Honeycutt at 01:58 AM on 16 September 2010Video update on Arctic sea ice in 2010
BP... I'm trying to figure out the point of these North Pole pictures. I know what you're responding to, I've read the whole thread, but do you really think these are conclusive proof of anything? Do you think this means arctic ice is in overall the same condition today that it was 60 years ago? It strikes me as an act of cherry picking to locate photos which represent single data points to try to infer something larger. I had a teacher in high school who said, "Believe nothing you hear and only half of what you see." In that vein, I would be more swayed by data on the state of the ice during those time periods. Similarly, as I mentioned before, Dr Barber's lecture linked above was extremely compelling because of the first hand data he provided. -
Berényi Péter at 01:45 AM on 16 September 2010Video update on Arctic sea ice in 2010
#38 CBDunkerson at 22:29 PM on 15 September, 2010 The image you posted looks more like 80% concentration. A couple of years ago scientists thought that was possible because the pole was covered with first year ice for the first time in the satellite record. Since then the multi-year ice has all but disappeared Have a look at this image please (click for larger version).
It is USS Skate (SSN 578) on 17 March 1959, first through-ice surfacing at the North Pole ever. As you can see the ice is less than a foot thick (in March!). It can't be multi-year ice, can it?
Of course it was before the satellite record started, so I suppose it does not count.
(They were basically testing "the ability of submarines to operate in and under the Arctic ice in the dead of winter". Test was passed. Considering the strategic importance of the region during the Cold War I wonder how much information concerning Arctic ice conditions is buried in the US, UK & USSR Navy archives)
-
Esop at 01:33 AM on 16 September 2010The Pacific Decadal Oscillation and global warming
Back in 2008 deniers promised a coming mini ice age due to the negative PDO and low solar activity. Looking at the 2010 global average temperatures, it seems that they were somewhat off target with their predictions. Not hugely surprising, really. -
Albatross at 01:28 AM on 16 September 2010Video update on Arctic sea ice in 2010
BP @36, First, I concur with what CBDunkerson said. Also, posting that image is misleading. Here is why: I could not find images to compare for 18 May 1987, but here is what your "rotten" ice looked later that year (1987) around the middle of September, compared to the same time this year. And since you brought it up, according to NSIDC, in March 1987 about 40% of the Arctic sea ice was comprised of ice that was at least 4 years old, by March 2010 less than 7% of the sea ice was at least 4 years old. That equates to losing about 2.5 million km^2 of ice four years or older. -
huntjanin at 01:04 AM on 16 September 2010The Pacific Decadal Oscillation and global warming
This is off-topic but I don't know where else to post it. If anyone can tell me what, if anything, Miami plans to do to deal with 1 m. of sea level rise by 2100, please contact me off-list at huntjanin@aol.com. -
michael sweet at 00:38 AM on 16 September 2010Video update on Arctic sea ice in 2010
Adrian: At post 23 you said "If I'm not mistaken North America has been cooling for the past decade." At post 27 you said "Which is kind of unfortunate because I enjoyed the extra week or 2 of golf in the spring and autumn up here in Canada." Your own personal observations contradict your assertions that you got at WUWT. You look stupid when you make these type of claims. You are mistaken in your claims that North America has been cooling. Your observations have been correct. I explained the DMI graph at post 14. WUWT has deceived you. The people at this blog will explain to you what you do not understand. If you only want to argue you should find another place to post. -
Alexandre at 00:23 AM on 16 September 2010The Pacific Decadal Oscillation and global warming
This is a favourite subject of a well-kmown skeptic meteorologist here in Brazil. Not surprisingly, he also claims on occasion that it's the Sun, it's a natural cycle related to deglaciation, and on top of that we're not warming at all. It's just urban heat island effect. -
mfripp at 00:22 AM on 16 September 2010What about that skeptic argument that Jupiter is warming?
KR, thank you. This makes sense. -
Tarcisio José D at 23:51 PM on 15 September 2010Does more extreme rainfall mean more flooding? Answer: Not always
thingadonta (#2) Here in the Amazon (rainforest) we live with the two situations. Floods and drought due to soil sealing to 15 cm deep, which extends up to 50 cm. -
Arkadiusz Semczyszak at 23:34 PM on 15 September 2010How we know the sun isn't causing global warming
It should also refresh the knowledge on the D-O: Orbital modulation of AMOC variability T. Friedrich et al., 2009.: “However, without careful considerations of the orbital influences on internally generated millennial-scale AMOC variability, a convincing assessment of the mechanisms for observed D-O variability remains elusive.” About the differences between D-O and BE decides to sea ice cover on the GIN sea - the polar front position - the Sun, however, both choosing - AMOC. Melting of glaciers is secondary. Millennial and sub-millennial scale climatic variations recorded in polar ice cores over the last glacial period, Capron et al. 2010.: “This shows that for extraordinary long stadial durations the accompanying Antarctic warming amplitude cannot be described by a simple linear relationship between the two as expected from the bipolar seesaw concept. We also show that when ice sheets are extensive, Antarctica does not necessarily warm during the whole GS as the thermal bipolar seesaw model would predict, questioning the Greenland ice core temperature records as a proxy for AMOC changes throughout the glacial period.” “The results display a succession of abrupt events associated with long Greenland Inter Stadial phases (GIS) enabling us to highlight a sub-millennial scale climatic variability depicted by (i) short-lived and abrupt warming events preceding some GIS (precursor-type events) and (ii) abrupt warming events at the end of some GIS (rebound-type events).” Thus, in previous periods of warming in a long time inter LG period, we had BE ... Extreme deepening of the Atlantic overturning circulation during deglaciation, Barker, 2010. It shows that the AMOC is a change from weak to strong, has resulted in: “During the Bølling-Allerød (B–A) warm phase, 14,600 years ago, temperatures rose by 9 degrees Celsius over the course of just a few decades.” Analyzing the same period - Interhemispheric coupling, the West Antarctic Ice Sheet and warm Antarctic interglacials, Holden et al., 2010.: write: “Ice core evidence indicates that even though atmospheric CO2 concentrations did not exceed ~300 ppm at any point during the last 800 000 years, East Antarctica was at least ~3–4 °C warmer than preindustrial (CO2~280 ppm) in each of the last four interglacials. During the previous three interglacials, this anomalous warming was short lived (~3000 years) and apparently occurred before the completion of Northern Hemisphere deglaciation.” “We present two 800 kyr transient simulations using the Intermediate Complexity model GENIE-1 which demonstrate that meltwater forcing generates transient southern warming that is consistent with the timing of WPTs, but is not sufficient (in this single parameterisation) to reproduce the magnitude of observed warmth.” -
Arkadiusz Semczyszak at 23:31 PM on 15 September 2010How we know the sun isn't causing global warming
„... the D-O cycle ...” Rahmstorf said, however, that the 1470 +/- 500 years change, corresponds to the Sun - “We conclude that the glacial 1,470-year climate cycles could have been triggered by solar forcing despite the absence of a 1,470-year solar cycle.” Keeling & Whorf, The 1,800-Year Oceanic Tidal Cycle: A Possible Cause of Rapid Climate Change, 2000, (what's interesting is not quoted by Rahmstorf et al. 2003) writes: “We propose that such abrupt millennial changes, seen in ice and sedimentary core records, were produced in part by well characterized, almost periodic variations in the strength of the global oceanic tide-raising forces caused by resonances in the periodic motions of the earth and moon. A well defined 1,800-year tidal cycle is associated with gradually shifting lunar declination from one episode of maximum tidal forcing on the centennial time-scale to the next. An amplitude modulation of this cycle occurs with an average period of about 5,000 years, associated with gradually shifting separation-intervals between perihelion and syzygy at maxima of the 1,800-year cycle. We propose that strong tidal forcing causes cooling at the sea surface by increasing vertical mixing in the oceans. On the millennial time-scale, this tidal hypothesis is supported by findings, from sedimentary records of ice-rafting debris, that ocean waters cooled close to the times predicted for strong tidal forcing.” Solar cycle counting 2300 years and lunar cycle of 1.800 years. Both cycles are shifted against each other for 500 years. On the "lunar tidal" the Sun has a significant impact. Chaos and Intermittency in the Solar Cycle, Spiegel, 2009.: “We have revealed specific patterns in the magnetic activity between successive grand minima which tend to recur approximately every 2300 yr but occasionally alternate with irregular changes. Such intermittent activity behavior indicates low dimensional chaos in the solar dynamo due to the interplay of its dominant modes. The analysis showed that in order to forecast activity level in forthcoming cycles, one should take into account long-term changes in sunspot activity on a ≈2300-yr timescale. “ Obecne Bond Events mogą wynikać z rezonansu stochastycznego D-O (the inertia of the system - despite the lack of direct impact - a cycle of loading), or - more likely - with the cycles interaction - magnetic and gravity, of the Sun and Lunar. Probably "summation" cycles - above solar and lunar (dependent on the Sun) when the overlap in the respective phases (during glaciations occur after a longer interval between the D-O - multiples of 1,470 years) is "guilty" for the emergence of quasi-cycle - 1470 + / -500 years. -
Arkadiusz Semczyszak at 23:29 PM on 15 September 2010How we know the sun isn't causing global warming
Let's go back to reading the textbook: “Solar Influences on Climate”: “As in the ozone analysis, the lower stratospheric temperature response is indicative of a large-scale dynamical response, e.g. changes in net equatorial upwelling rates (Shibata and Kodera 2005; Gray et al. 2009).” “... the majority of climate models employed to date ... ... represent primarily the ‘bottom-up’ TSI mechanism and have a very poor, or no, representation of the ‘top-down’ mechanism that requires spectral variations in solar radiative input and ozone feedback effects. Only a few have an adequate representation of the stratosphere and even those do not generate a complete representation of stratospheric effects such as an internally consistent quasi biennial oscillation. Some of the models employed for future IPCC assessments are planned to incorporate these processes, and thus should be better placed to assess the importance of these effects.” “Thus a precise determination of solar RF depends on the response of stratospheric temperatures and ozone to the changes in solar irradiance. These are not well established (see section 3.1) so that published estimates of the ozone amplification of direct TSI forcing show a very wide range (Haigh 2007; Gray et al. 2009) with even THE SIGN of the effect remaining uncertain.” “Modulation of ENSO by solar forcing appears to be consistent with at least some paleo-climate evidence, especially for the Americas where multiple proxies such as fire scars, lake varves (stratified deposits of glacial clay), tree rings, etc. indicate correlations between precipitation and solar irradiance that are similar to ENSO-related precipitation anomalies (Graham et al. 2007). As discussed in section 3.2.2, a mechanism of coupled atmosphere-ocean response to solar forcing in the tropical Pacific has been proposed (e.g. Meehl et al., 2003, 2008). Additionally, the UV/ozone feedback mechanism appears to cause enough heating near the tropical tropopause to significantly affect the tropical hydrologic cycle, with regional impacts on precipitation that are also broadly similar to those related to ENSO changes (Shindell et al., 2006). Thus the two mechanisms may operate together to create the tropical/subtropical response to solar forcing with associated amplifying cloud feedbacks (Meehl et al., 2009).” ... so even though that: “The PMOD TSI data have fallen to unprecedentedly low levels during the current solar minimum, although estimates vary on the magnitude of this decline (Lockwood, 2010).The mean of the PMOD TSI composite for September 2008 is 1365.1 Wm-2, which is lower than that for the previous minimum by more than 0.5 Wm-2. [back to the level of 1924]” ... “Note, however, that if the recent SORCE/SIM measurements of spectrally resolved solar irradiance (discussed in section 2.2.2) are correct then solar radiative forcing at the tropopause would vary out of phase with tsi. In this case, assessments of solar influence on climate, at least over the 11-yr cycle and possibly on the longer term, would need to be ENTIRELY REVISITED(Haigh et al. 2010).” “Recent measurements of SSI by the SORCE/SIM satellite instrument suggest that variations in the UV may be much larger, by a factor of 4-6, than previously assumed (Harder et al. 2009). If correct, this would imply a very different response in both stratospheric ozone and temperature (Haigh et al. 2010 ...).” Although many questions (!), the title “proudly” proclaims: “ ... the sun isn't causing global warming” I would - though for decency - as he Svalgaard - "?" here: (No?) Century-scale Secular Variation in HMF, EUV, or TSI, (2007.) -
Tarcisio José D at 23:28 PM on 15 September 2010Does more extreme rainfall mean more flooding? Answer: Not always
Criscanaris (#3) The precipitation, when it is absorbed by the soil represents a negative feedback because the water vapor is the driver of climate. It happens that our soil is sealed by the accumulation of ammonia from the decomposition of organic matter (soil science) which is a natural phenomenon plus the manufacture of fertilizers based on ammonium. See this presentation:
Greenhouse effect, the bigger the better.
We must pay attention to the rate of absorption of water by soil (mm / h) because the rains have not only increased speed in millimeters per 48 hours. -
Riccardo at 23:04 PM on 15 September 2010How we know the sun isn't causing global warming
Ken Lambert, my point was only on a change in albedo due to an increase in cloudiness. Just to say that we need to consider all the effects produced by a given change. -
Ken Lambert at 22:43 PM on 15 September 2010How we know the sun isn't causing global warming
Riccardo #51 and Andreas #52 My unanswered post in **"What caused early 20th century warming"** is revised here and I think a non-trivial calculation Riccardo. All the 'anthropogenic forcings' in Fig 2.4 IPCC AR4 and repeated by Dr Trenberth's famous paper in Figure 4, are relative to a baseline of 'zero' in AD1750. The +0.12W/sq.m for 'natural' Solar forcing is baselined to what? Was it zero in AD1750? If it was not or we don't know; then it should not be added and subtracted from the AG forcings based on 'zero' in AD 1750. Figure 1 from **cited** thread (1713-1996) seems to suggest a baseline TSI at 1365.5W/sq.m, but who is to suggest that the solar forcing was 'zero' in AD1713 given the complex orbital cycles which vary the Earth's exposure to the sun over interglacial time scales. Is 1365.5W/sq.m the 'zero' baseline where the Earth system is neither warming nor cooling in the absence of human induced post-industrial forcings?? The critical point is that the energy accumulation of the Earth system does not necessarily stop when the TSI is flat. This energy is the integral of a constant unbalanced 'forcing' in W/sq.m wrt time represented by the area under the forcing curve which rises linearly with time elapsed. A constant 0.12W/sq.m forcing over one year is 20E20 Joules, which over a century is 2000E20 Joules. 5-6E20 Joules/year covers all the arctic ice melt, land ice melt and land heating (according to Dr Trenberth). So if for example the Earth was warming in AD1713 at a small Solar forcing of say 0.06W/sq.m (half the current IPCC Solar forcing number), and we assume the same shape of the TSI curve since then is offset by an extra 0.06 x 4 /0.7 = 0.34W/sq.m then that would add an extra 10E20 Joules/year to the Earth system for nearly 300 years which is an extra 3000E20 Joules - a big number - most of which must go into OHC. Andreas suggests that the unbalanced forcing was more like 0.24W/sq.m referenced from the Maunder Minimum which would add 40E20 Joules/year for roughly 300 years from AD1715 - which is 12000E20 Joules. Given Dr Trenberth's claimed current warming imbalance from AG and Solar forcings is 145E20 Joules/year, 12000E20 Joules equals 83 years warming at the current rate and much longer at reduced rates averaged over the last 50-100 years. If something like 90% of 12000E20 Joules were sequestered in the oceans over 300 years by the known processes of heat transfer and upper layer circulation, with exhanges released to the atmosphere via complex events like ENSO, La Nina and AMO - I suggest it is entirely feasible for a large portion of observed warming to be accounted for by long term Solar imbalance since the LIA. -
CBDunkerson at 22:29 PM on 15 September 2010Video update on Arctic sea ice in 2010
adrian smits #32: "Does it not show approximately 3 tenths of a degree of warming since 1979?" I assume you are talking about the Arctic region. In which case your error is thinking that the image shows TOTAL warming. It does not. It shows the trend per decade. That is, 0.3 C average warming each decade since 1979... which translates to about 1 C total warming since 1979. BP, yes there are often spots of open water at the North Pole. What has not yet been seen is a year when the ice at the North Pole melted out completely (or down to the 15% concentration easily determined by satellites). The image you posted looks more like 80% concentration. A couple of years ago scientists thought that was possible because the pole was covered with first year ice for the first time in the satellite record. Since then the multi-year ice has all but disappeared, but the pole still hasn't melted out. Arctic currents tend to concentrate ice in the area and thus it now seems likely that we won't see a truly ice free North Pole until the whole Arctic is nearly ice free... though if PIOMAS volume declines are accurate and continued apace that'd be just a few years away. -
JMurphy at 22:11 PM on 15 September 2010Video update on Arctic sea ice in 2010
Berényi Péter, thanks but the date originally mentioned was the 1950s... -
Berényi Péter at 21:54 PM on 15 September 2010Video update on Arctic sea ice in 2010
#35 JMurphy at 20:51 PM on 15 September, 2010 Perhaps you should give some links for some of those pictures - direct links, of course, and not via secondary websites. You can check this conceivably authoritative site out:
An image gallery at the same site: Submarines Under Ice.
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JMurphy at 21:45 PM on 15 September 2010The contradictory nature of global warming skepticism
With regard to polar bears, has anyone posted a link to Polar Bears International ? The greatest challenge to the conservation of polar bears is ecological change in the Arctic resulting from climatic warming, according to the IUCN Polar Bear Specialist Group (PBSG). [July 6, 2009, Copenhagen]
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