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Comments 81451 to 81500:
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Albatross at 03:07 AM on 25 June 2011Websites for Watching the Arctic Sea Ice Melt
EricR @96, "The IPCC predicted that it would take a 5.5C temperature rise to melt Greenland, and it would take several centuries. Recent studies show that the melt rate is significantly less." That statement is demonstrably wrong. Your biased interpretation of the papers (which you don't seem to really understand) have been addressed by Michael and Skywatcher, and you did not recognize your error, ignored their insights and just tried to re-frame your argument and shift the goal posts @100. Doing so is incredibly ungrateful, people are trying to help you understand this better, but you appear to have too many mental hurdles/blocks (and no I am not saying you are dim or anything like that) in the way I doubt you even followed the link to Tamino's statistical analysis of Arctic sea-ice volume. Monthly Arctic sea-ice volume anomalies:
September Arctic sea-ice volume anomalies with quadratic fit:
Source]
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michael sweet at 02:38 AM on 25 June 2011Websites for Watching the Arctic Sea Ice Melt
Eric, What about my questions about reversibility here?? You have chosen one of my comments and ignored the rest. You claimed that nothing is irreversible. What will reverse the flooding, drought, fires and ocean acidification that already exist? Your claim that all is reversible is not supported by showing that it is not yet known how much sea level will rise in the next few decades. It may just as well be true that sea level will rise more than 2 meters by 2100 as that it will be less than 1 meter, uncertainty cuts both ways. Your choice of only the most optimistic models is unlikely to hold up. -
Albatross at 02:36 AM on 25 June 2011Sea Level Hockey Stick
BP @94, "Anyway, this GIA thing only gives a -0.3 mm/year contribution to sea level rise." Well there you have it folks, BP agrees with the University of Colorado, and refutes the ridiculous assertions being made here. -
Albatross at 02:27 AM on 25 June 2011Sea Level Hockey Stick
BP, I commend your obfuscation efforts @80. On the surface of it, and ignoring your unsubstantiated hypotheses and musings, you may (or may not) have a out about the GIA correction. Can we look forward to you writing up and submitting a formal rebuttal to the journal, or are you simply here to grandstand? But before that, perhaps we should show what they actually say in the paper: "A constant rate of subsidence (with no error) was subtracted from the Sand Point (1.0 mm/y) and Tump Point (0.9 mm/y) records. These rates were estimated from a US Atlantic coast database of late Holocene (last 2000 y) sea-level index points (13, 15). Use of a constant rate is appropriate for this time period given Earth’s rate of visco-elastic response (14). The resulting records are termed “GIA-adjusted,” expressed relative to mean sea level from AD 1400–1800 and visually summarized by an envelope (Fig. 2C)." So a constant correction was applied to all the data, and just as if a temperature sites has a systematic bias, that systematic bias/offset does not affect the trend.Moderator Response: [Dikran Marsupial] Please can we all dial back the tone of the discussion a notch or two, and keep things on a constructive a level as possible. -
pbjamm at 02:26 AM on 25 June 2011Sea Level Hockey Stick
Camburn@74 It is right there in the OP: "IPCC AR4 showed that local sea-level trends differed by up to 2 mm/y from the global mean over AD 1955–2003, which implies deviations of up to ±10 cm at some locations (but ±5 cm along most coastlines) as the sum of forced and unforced effects. This analysis suggests that our data can be expected to track global mean sea level within about ±10 cm over the past two millennia, within the uncertainty band shown for our analysis." So if I am understanding it correctly, this regional proxy is average when compared to global proxies. Not everyone can be a unique snowflake! On the Bell Curve someone has to be average. -
Berényi Péter at 02:13 AM on 25 June 2011Sea Level Hockey Stick
The only process that has a measurable effect on ocean basin volume is GIA (Glacial Isostatic Adjustment). Currently volume of ocean basins is increasing at a 100 km3/year rate, because vast continental areas that were once covered with miles of ice, having got rid of this weight, started rising. It can only happen if mantle material (which behaves as a high viscosity fluid) is sucked in from below the oceans to support rising rock. That is, ocean basins next to previous ice sheets (like the Laurentide and Fennoscandian one) are getting progressively deeper. All other processes like plate tectonics or sedimentation operate on much longer time scales and their contribution is negligible to millennial rates of ocean basin volume change. Anyway, this GIA thing only gives a -0.3 mm/year contribution to sea level rise. As for ocean water volume changes, relative sea level measurements at continental margins (tide gauges) are not representative, because continental margins themselves are sinking on average. There are two reasons for that. One is still GIA, because sea level is some 120-140 m higher now than it was twenty thousand years ago. This additional weight of seawater is slowly pushing continental margins down (relative to the true geoid). The other one is ground water depletion which (through decreasing pressure in water table) induces sinking of sedimental layers in many coastal regions. Therefore part of sea level rise as measured by tide gauges is in fact (coastal) land level decrease. Volume of sea water can change in two ways. One is steric when water mass is unchanged and only its volume changes due to decreasing (or increasing) density, mainly because of changes in heat content. In this respect sea level behaves as a thermometer. Not a terribly good one though, because volumetric thermal expansion coefficient of seawater depends heavily on both temperature and pressure, so the addition of the same amount of heat can produce quite different sea level changes depending on which part of the ocean absorbed it. As volumetric thermal expansion coefficient is increasing with both temperature and pressure, while water temperature decreases with depth, there is a layer at about 1000 m below the surface where absorption of heat has the least effect on sea level. Expansion due to the same amount of heat absorbed increases both below and above this level (the former because of increasing pressure, the latter because of increasing temperature). The other way to change sea water volume is to change its mass, that is, to add some more water to the oceans or subtract it from them (and store it elsewhere). The main processes here is melting of land based ice (or snow accumulation), water storage in reservoirs (negative contribution) and groundwater depletion. These processes do not have much effect on heat content of the climate system. The last two has simply none, while melting ice uses almost a hundred times less heat to produce the same sea level change as (steric effect of) heat absorption by water. ( -Snip- )Response:[DB] Off-topic unsupported conclusions snipped.
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Albatross at 02:08 AM on 25 June 2011Sea Level Hockey Stick
"When dot-cloud radar scanners can penetrate 3700m of seawater and measure the bottom to an accuracy of 0.1mm, we could determine if the bathtub is growing or shrinking in volume. If the bottom was rising 1-2mm per year - there is your SLR." Surely they jest? What a lovely red herring. Occam's razor applies here, and some would rather have us debate how many angels can dance on a pin head, rather than face the fact that the global sea levels are rising in step with increasing temperatures as they have in the past (and here I mean over statistically significant periods of time). This paper has obviously causing "skeptics" and those in denial about AGW some cognitive dissonance and their posts here show that. Posts such as the one I quoted above are trolling and baiting, and nothing to so with the paper being discussed. It is also a perfect example of how someone in clearly denial can rationlize what they so dearly wish to believe. That is not science either. They are also examples of fabricating doubt, confusion and exaggerating uncertainty, claiming that "we do not know everything so we know nothing" all tricks routinely plied by the "skeptic" and denialist misinformation machine. Can we please get back on track folks. -
skywatcher at 02:07 AM on 25 June 2011Websites for Watching the Arctic Sea Ice Melt
Eric, is the trend in sea ice volume or in minimum sea ice extent linear or nonlinear? And please do not insult everyone's intelligence by suggesting that the trends are based on 'one or two points'! These things can and indeed have been assessed properly, and we do not need to rely on your 'anticipation' to evaluate the shape of the current trend. -
Eric the Red at 01:55 AM on 25 June 2011Websites for Watching the Arctic Sea Ice Melt
JMurphy, I find no one in the Hansen report were he says that the amount of CO2 added to the atmosphere today is enough to raise sea levels 5m. -
Eric (skeptic) at 01:51 AM on 25 June 2011Websites for Watching the Arctic Sea Ice Melt
#92, moderator, if went to zero tomorrow CO2 would immediately exponentially decay to half way back to 280 in less than 48 years. There is simply no other possibility considering how much we have put in the atmosphere and how much remains. I posted a simple spreadsheet showing this here: https://www.iwork.com/document/en/?a=p1415598010&d=CO2growth.numbersModerator Response: [Dikran Marsupial] You would indeed get a fairly swift reduction half way back to the pre-industrial level (although 48 years would be an optimistic estimate IIRC), however the decay would not be a simple exponential and the reduction to a quater of the way to the pre-industrial equilibrium would take very much longer. -
JMurphy at 01:15 AM on 25 June 2011Renewables can't provide baseload power
rcglinski, did you actually read the report that the graph came from ? In it, it states this : In 2050, energy demand is 15 per cent lower than in 2005. Although population, industrial output, passenger travel and freight transport continue to rise as predicted, ambitious energy-saving measures allow us to do more with less. Industry uses more recycled and energy-efficient materials, buildings are constructed or upgraded to need minimal energy for heating and cooling, and there is a shift to more efficient forms of transport. Now, straight-faced or otherwise, what are your arguments against that ? For further information, read the report, especially from page 44. -
dorlomin at 01:06 AM on 25 June 2011A Detailed Look at Renewable Baseload Energy
Great article, lot to digest. -
rcglinski at 00:57 AM on 25 June 2011Renewables can't provide baseload power
The very first graph has global energy consumption peaking soon and then declining. That doesn't pass the straight face test. -
J. Bob at 00:37 AM on 25 June 2011Sea Level Hockey Stick
Ken Lambert @ 89, says "When dot-cloud radar scanners can penetrate 3700m of seawater and measure the bottom to an accuracy of 0.1mm, we could determine if the bathtub is growing or shrinking in volume. If the bottom was rising 1-2mm per year - there is your SLR.". That was my point at the end of #48. There is still a lot we have little knowledge of, including sea floor topography. -
JMurphy at 00:34 AM on 25 June 2011Websites for Watching the Arctic Sea Ice Melt
Eric the Red wrote : "My comments were to counter michael's claims that if we stopped emitting CO2 today that temperatures would continue to rise dramatically, resulting in several meters of sea level rise." Are you referring to michael sweet's comment at 91 ? If so, I can see no use of any form of the word 'drama' and he links to a paper by Hansen et al which predicts a sea-level rise of up to 5m. What would you call 5m, if not 'several' ? Can you specify where your use of the word 'dramatically' comes from (or withdraw it, if you can't), and show how your argument against Hansen et al is backed by peer-reviewed research. -
Eric the Red at 23:53 PM on 24 June 2011Websites for Watching the Arctic Sea Ice Melt
All, My comments were to counter michael's claims that if we stopped emitting CO2 today that temperatures would continue to rise dramatically, resulting in several meters of sea level rise. My point was that nothing that has happened to date is irreversible. No one has presented anything to dispute that contention. Speculating that future events will happen does not constitute evidence. What is the best way to predict the future? Simple, by looking into the past. Some may call this optimistic, becasue I am not anticipating acceleration in the trends. Can you actually say something is accelerating based on one or two points? Do you reason to believe that the trend is nonlinear? -
JMurphy at 23:50 PM on 24 June 2011Linking Extreme Weather and Global Warming
Eric the Red wrote : "Overall, AGW predicts greater precipitation, but not snow." Precipitation is precipitation, whether it falls as rain or snow, and others here have already shown how snow can be more likely, depending on local or regional conditions. More information and links available from Jeff Masters : Another interesting result from the Changnon et al. (2006) paper of Figure 2 is the relationship between heavy snowstorms and the average winter temperature. For the contiguous U.S. between 1900 - 2001, the authors found that 61% - 80% of all heavy snowstorms of 6+ inches occurred during winters with above normal temperatures. In other words, the old adage, "it's too cold to snow", has some truth to it. The authors also found that 61% - 85% of all heavy snowstorms of 6+ inches occurred during winters that were wetter than average. The authors conclude, "a future with wetter and warmer winters, which is one outcome expected (National Assessment Synthesis Team 2001), will bring more heavy snowstorms of 6+ inches than in 1901 - 2000. The authors found that over the U.S. as a whole, there had been a slight but significant increase in heavy snowstorms of 6+ inches than in 1901 - 2000. So, there is evidence that the average climate of the U.S. over the past 100 years is colder than optimal for heavy snow events to occur. If the climate continues to warm, we should expect an increase in heavy snow events for a few decades, until the climate grows so warm that we pass the point where winter temperatures are at the optimum for heavy snow events. However, a study by Houston and Changnon (2009) on the most severe types of snowstorms--the "top ten" heaviest snows on record for each of 121 major U.S. cities--shows no upward or downward trend in the very heaviest snowstorms for the contiguous U.S. between 1948 - 2001. And Joe Romm : Research says big snow storms not inconsistent with — and may be ampliflied by — a warming planet -
Tom Curtis at 23:50 PM on 24 June 2011Sea Level Hockey Stick
Ken Lambert @90, "I am not going to check your sums this time Tom, but I do wonder why you present such an array of number facts and then cast doubt on your own sums which are supposed to make your point." Because, KL, unlike you I would rather arrive at the truth than make a point. That is why I can admit my errors, while you give every evidence of being incapable of doing so. -
Ken Lambert at 23:41 PM on 24 June 2011Sea Level Hockey Stick
Tom Curtis #84 Sediments are a very small contributor globally - less than 0.2mm/annum by my rather old sum extrapolating the Yangtze River flow. "Please by all means check my maths as I am notorious for errors in that area, but this simple reality check suggests there is no significant impact on ocean volume by sedimentation" I am not going to check your sums this time Tom, but I do wonder why you present such an array of number facts and then cast doubt on your own sums which are supposed to make your point.Moderator Response: [Dikran Marsupial] Please stick to discussing the science, rather than comments regarding the motives of the participants. As this is an area where you have tended to sail rather too close to the wind with respect to the comments policy, it would be well worth refraining from such comments entirely. As it happens, explicitly stating any uncertainties in ones argument is standard operating procedure in the sciences. "If a man will begin with certainties, he shall end in doubts: but if he will be content to begin with doubts, he shall end in certainties" - Francis Bacon -
Ken Lambert at 23:32 PM on 24 June 2011Sea Level Hockey Stick
Tom Curtis #84 BP#80 BP seems to me making good unanswered points. This whole SLR debate should be reframed as a VOWIO (volume of water in oceans) debate. Because that is the real measure of warming via thermal expansion and ice melt. I did some numbers a while ago on sediments and biomass - and they were one or two orders of magnitude smaller than the 2-3mm/year of SLR. When dot-cloud radar scanners can penetrate 3700m of seawater and measure the bottom to an accuracy of 0.1mm, we could determine if the bathtub is growing or shrinking in volume. If the bottom was rising 1-2mm per year - there is your SLR. -
CBDunkerson at 23:18 PM on 24 June 2011The chief troupier: the follies of Mr Monckton
Ken wrote: "Al Gore's movie "An Inconvenient Truth" was found unfit for use as an educational tool..." More fiction. An Inconvenient Truth continues to be distributed in the UK as educational material. The judge in the Dimmock case (which you presumably refer to) found that it was "substantially founded upon scientific research and fact" and thus allowed for use in schools. The judge did require that a 'guidance' document accompany showing of the film to inform students that a few parts of the film expressed views which were still disputed by some skeptical scientists. Seriously, don't you ever get tired of being lied to? As to Williams... you now argue that he has a closed mind because he didn't read the 'Climategate' letters. That's arguable... but very different from your assertion that he (among others) is guilty of outrageous claims and distortions. For which you have still provided no examples that are not demonstrably false. -
Argus at 23:14 PM on 24 June 2011Sea Level Hockey Stick
#86 ... and also, on the other hand, that many commentators on this site seem to get genuinely happy for every new hockey stick that shows up!Moderator Response:[DB] I'm extremely certain that every single regular poster here would like nothing more than for a "silver bullet" to be found that makes the entire problem of the radiative physics of our fossil fuel emissions "go away". But being human, there is a natural tendency towards elation when we have solid scientific data showing the dissembling of the denialist movement to be exactly what it is: a house of cards built on shadows and myths.
[Dikran Marsupial] Proof that every cloud has a silver lining, even if it is only one atom thick! ;o) -
pauls at 22:53 PM on 24 June 2011Sea Level Hockey Stick
81, okatiniko - I realise this ha been declared OT but thought I'd make you aware of some developments since that 2004 paper. This is a comment on the paper published in 2006 pointing out errors in their methodology. Further discussion here. -
Marcus at 22:36 PM on 24 June 2011IPCC Report on Renewable Energy
Hey Rob, I'm totally with you on this-trust me. I was simply making the point that the coal industry-both in the US & Australia-rarely even *try* to rehabilitate the land they destroy, which is one of the reasons their costs are so low. Now they want to risk polluting our ground water by switching to *fracking*! Time to send this dinosaur of an industry into extinction! -
skywatcher at 22:31 PM on 24 June 2011Sea Level Hockey Stick
Methinks that some around here, and presumably on certain well-known blogs really don't like hockey sticks showing up in different kinds of palaeoclimate records... -
sgmuller at 22:30 PM on 24 June 2011Rogues or respectable? How climate change sceptics spread doubt and denial
Where I first heard about the Galileo Movement I immediately thought that we could add a third bit of advice to an old saying. "Never play poker with a man called Doc, never eat at a place called Mom's and never trust a science organistaion calling itself the Galileo Movement." -
skywatcher at 22:21 PM on 24 June 2011Websites for Watching the Arctic Sea Ice Melt
Eric, from your own linked article about Greenland: "Richard Alley of Pennsylvania State University cautions that Price’s model does not provide an upper limit to sea level rise." Additionally, while I do not of course expect Greenland to disappear within my lifetime, the point is that we are setting up a chain of events that will not just reverse with a slight decrease in CO2. As for sea ice, try this discussion of sea ice volume. Do you think trends in Arctic sea ice are or are not showing accelerating declines. When does the acceleration show most clearly - when ice is thickest, or when ice is thinnest? Do you think you can put a straight line through data points (with no mechanical/physical reason why) and say that this will be the trend in the future? It would be nice to have your optimism, but real physical systems do not operate in the simplistic way you would like them to behave. -
Rob Painting at 22:18 PM on 24 June 2011IPCC Report on Renewable Energy
Land rehabilitation?, what about river and stream rehabilitation? And what the heck does 'rehabilitation' really mean anyway?, it can't realistically be rehabilitated. Those areas will be stuffed for generations. I really do hate it when polluters try to minimize the damage they cause by using weasel words. -
Marcus at 22:12 PM on 24 June 2011IPCC Report on Renewable Energy
Here's an interesting quote to put Quokka's claims about land use into perspective: "Based on current mining techniques, Mr. Nace says a solar thermal plant can produce 18 gigawatt hours per acre of land over a 60 year period; whereas a coal-fired power plant will generate 15 gigawatt hours per acre of mined land . This does not take into account the space required for toxic by-products such as fly ash. Compared to solar thermal, the land footprint of coal is about 20 percent greater." and this:"While in the US mining companies are obligated to perform restorative work after exhausting an area of coal, Nace says that this rarely occurs." Once again I wonder how much more coal would cost if these mining companies *did* have to pay for land rehabilitation? -
Marcus at 22:02 PM on 24 June 2011IPCC Report on Renewable Energy
Many sources of renewable energy are already comparable to subsidized coal on a price per kw-h basis. Small-Scale Hydro, Biomass Gas, Geothermal & On-Shore Wind.....and most of them take up very little land compared to coal. Even CSP & Photovoltaic Power are falling fairly rapidly. Yet Coal continues to have an unfair advantage because-in Australia for example-land rehabilitation & disposal of fly-ash waste are paid for by State Governments, they get free access to roads & rail, they get cheap water & a diesel fuel rebate. Without these subsidies, I doubt they could offer electricity for the price they currently do. I'd also say that subsidies are very important for relatively new industries-if only to help them achieve the economies of scale needed to get price reductions. My question is why should the coal & oil industry-both of whom are incredibly profitable-continue to receive significant tax-payer subsidies when it gives them such an unfair advantage in the energy market? -
Rob Painting at 22:02 PM on 24 June 2011The Last Interglacial - An Analogue for the Future?
Somes_J - just expanding a bit more on Steve's comment: because Earth's orbit was more eccentric (elliptical) back then, it's obliquity (rotational tilt relative to its plane of orbit) greater and the northern hemisphere summer coincided with perihelion (closest part of Earth's orbit to the sun), it meant the NH summer received greater solar heating than today. By contrast the Eemian winter would have been much cooler, so there would have been a greater difference between summer and winter temperatures in the NH (seasonality) this would have had a marked effect of the hydrological cycle at that time, such as the African Monsoon. See Herold 2009 for an examination of this issue. For the Holocene Climatic Optimum (HCO), once again astronomical factors meant a greater warming in the NH summer and a wetter African period. Changing orbital forcing, from the HCO to today, lead to a cooling in the NH and a change to the monsoonal pattern. As pointed out by Steve, the factors in play today are a bit different. Living in the world of the Eemian?, be nice if the world was as we'd like to be but even small changes in the global mean state, can mean drastic changes in extremes, such as rainfall intensity. The models do indicate that a warmer world is a wetter world, but that's an oversimplification, generally dry areas are expected to get drier (the south-western USA for example) and wet areas wetter, but again we expect greater seasonality even in wet areas the rainfall is expected to be in the form of less frequent rain, but much heavier downpours (i.e. bigger floods). Me personally, I'd like to avoid that future world. -
Dikran Marsupial at 21:48 PM on 24 June 2011Sea Level Hockey Stick
To add (very little) to what Tom says, there is also the point that sediment doesn't just sit at the bottom of the ocean, it gets compressed into rock and then gets subducted under continental plates. I suspect the rates of sedimentation and subduction are roughly in equilibrium on geological, in which case sedimentation would only cause a rise in sea level if there was a change in sedimentation rates. If there was a good reason to think sedimentation was an significant issue, you can be sure it would be taken into account in the adjustments made to the raw data. -
Tom Smerling at 21:46 PM on 24 June 2011IEA CO2 Emissions Update 2010 - Bad News
John A small addition might help make this (excellent) post more clear to the reader. When I reread the post this a.m., I noticed this: "Figure 4: Hadley Centre modeled warming by 2100 in various CO2 emissions scenarios (Source) "Right now we're on track with the orange and red arrows in Figure 4. If we continue with this business-as-usual high emissions path, the consequences could be dire. Some of the impacts listed in the IPCC report for global warming of 3–4°C above pre-industrial levels include...." But "orange and red arrows in Fig. 4" lead to + 4-5.2 C and + 5.5-7.1 C warming --- not 3-4 C. It's certainly OK to say "we'll let's just assume we're going to change our ways...and get back down to the "blue arrow" = + 2.9-3.8 C warming. But you should be explicit that you are switching scenarios in that paragraph. Different people might label that your assumption -- that humanity will acts "late and slow" to get back to the "blue arrow" where emissions return to 1990 levels by 2050" -- as either optimistic, reasonable or minimizing (a form of denial). But unless I am missing something here, it is simply confusing. One sentence in the above paragraph, noting why you are "switching scenarios" would take care of it. -
Papy at 21:43 PM on 24 June 2011French translation of the Scientific Guide to 'Skeptics Handbook'
I'd like to add a link to the translation in French of 30 arguments from Skepticalscience. "Rendez-vous sur le site du RAC (Réseau Action Climat)". -
Tom Curtis at 21:29 PM on 24 June 2011Sea Level Hockey Stick
Argus @82, some maths: a) Length of the Somalian Coast Line: 3,025,000 Meters b) Length of the Kenyan Coastline: 536,000 Meters c) Length of the Tanzanian Coastline: 1,424,000 Meters d) Combined Length = a + b + c = 4,985,000 Meters e) Average Depth of the Ocean: 3,790 Meters f) Median Tectonic Motion of East African Rift: 0.002 Meters per annum. g) Approximate Median displacement of the Indian Ocean by the East African Rift = d * e * f = 37,786,300 Cubic Meters per Annum. h) Minimum Density of Sandstone: 2.2 ton per cubic meter i) Minimum mass of displacing rock form East African Rifting = g * h = 83,129,860 tons j) Annual Sediment Load deposited by the worlds rivers: 15.5*10^9 tons k) Ratio of deposited mass to mass of displacing rock in East African Rifting = j/i =~= 186.5 l) Maximum water displacement by deposited sediment = k * g =~= 7*10^9 Cubic Meters per Annum m) Surface Area of the Earth's oceans: 3.6*10^20 meters squared. n) Volume of a 1mm increase in sea level = 0.001*m= 3.6*10^17 meters cubed o) Ratio of maximum water displacement due to sedimentation to the volume increase from a 1 mm increase in sea level = l/n = 1.95*10^-8 or approximately 2 millionth of a percent. Please by all means check my maths as I am notorious for errors in that area, but this simple reality check suggests there is no significant impact on ocean volume by sedimentation. -
Eric the Red at 21:22 PM on 24 June 2011Sea Level Hockey Stick
Sphaerica, I have to admit that your posts regarding the fatter fish displacing more water left me in stitches. It was a welcome relief, slightly OT, but entertaining. I have to ask, with the sediment flowing downhill, and the fatter fish sinking, would that not cause the Earth to spin faster? -
Steve Brown at 21:15 PM on 24 June 2011The Last Interglacial - An Analogue for the Future?
@Somes_J - The key to the differences in environmental impacts between the Eemian and IPCC projections for the future will be due to the significant differences in forcings and feedbacks that are being observed and expected. For example, Eemian warming was mostly apparant at high northern latitudes due to the particular orbital configuration at the time and a correspondingly higher insolation. We currently have ~100 ppm more CO2 in the atmosphere and rising compared to the Eemian, which will contribute to enhanced greenhouse warming globally. Also, present day land use and deforestation will be contributing to different albedo feedbacks and differences to the hydrological cycle etc. The other key difference, as "LochNess" alludes to, is that the rate of change of warming and GHG increase going on today is unprecedented. The climatic changes during the Eemian happened over several thousand years and not in a few decades. -
Eric the Red at 21:07 PM on 24 June 2011The Last Interglacial - An Analogue for the Future?
Somes_J, You are correct in that warmer temperatures recent in wetter climates, and Africa is believed to have wetter during the two periods you described. Africa is also believed to have been drier during the last ice age. The desert areas are governed by the intertropical convergence zone (ITCZ), which follows the warmer temperatures, i.e. moves northward in the NH summer, and southward in the HN winter. Projections in a warmer world would cause an increase in the ITCZ, which would result in more rainfall in today's desert regions. Here is were the theories diverge. Some state that an expansion of the ITCZ will simply push the desert regions poleward, causing the semi-arid regions to dry into deserts. Others maintain that the deserts will shrink in size as the ITCZ expands, but the poleward side of the desert remain where htey are today. -
Eric (skeptic) at 21:04 PM on 24 June 2011Linking Extreme Weather and Global Warming
#193, Camburn, you are correct. The Canadians started filling their reservoirs in April based on a completely worthless (for this situation) treaty. They hit about 4000 cfs in April (see http://www.minotdailynews.com/page/content.detail/id/553971/Souris-River-system-tested.html and then proceeded to try to achieve the treaty value, rather than keep the flow at a higher precautionary rate. They proceeded with the same reservoir filling two more times (late May, and amazingly, earlier this month). The results are dramatic, a human-created flood with 34400 (current rate) being sent across the border today, ten times the treaty limit. For the sorry results see http://waterdata.usgs.gov/nd/nwis/uv?cb_00060=on&format=gif_default.=90&site_no=05114000 -
michael sweet at 20:58 PM on 24 June 2011Websites for Watching the Arctic Sea Ice Melt
Eric: You have presented data at last!! You have found an interesting article on Greenland. They model that the ice melt on Greenland will peak and then decrease as the temeprature increases. Melt last year was greater than they project for the coming, hotter decades. Hansen (linked above) projects that the melt will double every ten years. For the past 8 years the satelite data shows that melt has increased at a faster rate than Hansen expected. Perhaps your model will proove correct and the melt will slow down in the future, it will be interesting to see how this paper is received by the scientific community (it is too new to know how it will be received). Hansen made his projection several years ago and most people seem to think he is high, but the data support him so far. For sea ice you have also picked the longest projections for an ice free arctic. Maslink, linked above, projects an ice free Arctic as early as 2013. We will see in a few years, perhaps ths September, who is more correct. You always choose the most optimistic projections to base your choices on. Do you realize the risk associated with that course? You have not addressed my comments on flooding (20,000,000 people lost their homes in Pakistan alone, not to mention China, Australia and the USA), drought (largely responsible for the fires sweping the USA right now, Australia had it's share this year) or ocean acidification (which I did not mention before but is a severe effect that must be reversed). Which of these effects are reversible? How will they be reversed? Please provide more data, since you have shown the ability to find some. -
Eric the Red at 20:45 PM on 24 June 2011Linking Extreme Weather and Global Warming
michael, et. al., warming weather will add more moisture to the air, hence more precipitation. This will lead to greater rainfall. Snowfall occurs when the temperature is below freezing. In scaddamp #194, a warmer winter will result in more precipitaion, but it will fall in the form of rain, not snow. In general, warmer winters yield less snow. The largest snowfall occur when the temperature is nearest freezing. Very little snow falls when temperatures are much below freezing. In places were the average temperature is below freezing, then an increase in temperature will result in greater snowfall. Hence, Fairbanks, AK would expect to receive more snowfall in a warming world as the average annual temperature is ~-3C. Most of the rest of the world would see diminished snowfall as the temperatures rise further above freezing. Overall, AGW predicts greater precipitation, but not snow. -
michael sweet at 20:17 PM on 24 June 2011Linking Extreme Weather and Global Warming
Norman@188, As has been extensively discussed in this thread, AGW theory predicts more precipitation, faster warming in spring and thus more floods. Have you read the rest of the thread? Camburn @193: please provide references that support your claim that the dams did not release water when they should have. That has not been in the newspapers where I live. I have seen discussion on leting out water before the floods started to make room for the floods. -
JMurphy at 20:06 PM on 24 June 2011IPCC Report on Renewable Energy
And offshore wind requires no land ! -
LochNess at 19:50 PM on 24 June 2011The Last Interglacial - An Analogue for the Future?
Having worked in climate science for some years (a physicist by profession), I learnt is that it is the rate of temperature that is far more important than the absolute value of the temperature. Earth may very well have experienced higher temperatures than today, but as far as I understand, the rate of increase in the last ~30 years has been totally unprecedented. This should speak volumes, and one does find references to rate of increase in published literature very often, but somehow while making the public aware of how much humans are altering the climate, the issue of rate of increase is often left out. I've always found that surprising... -
Argus at 19:05 PM on 24 June 2011Sea Level Hockey Stick
#60 KR, and #61 Andy S, I did remember that sediments are heavier than water, I generously allowed for that: "160 billion tons maybe? It would replace about 50 billion tons of sea water." But my figure of 160 was probably too big. #70 and #63, - evening out over the geological long term, yes, but we may be in a phase now, where new mountain ranges are not forming, but where extensive farming opens up vast fields so that soil is blown inte the sea (as in southern Sweden). Also, the desert area increase (e.g. Sahara) results in more sand being blown into the ocean, as in this satellite photo. I am not trying to explain away measured sea level rise by erosion; I am merely saying it should be taken into consideration as a contributing factor. -
Somes_J at 18:22 PM on 24 June 2011The Last Interglacial - An Analogue for the Future?
I should add, before anyone suggests I look at the "it's not so bad" page I did but I didn't see any discussion of this. -
Somes_J at 18:19 PM on 24 June 2011The Last Interglacial - An Analogue for the Future?
Hello. Sorry if this is a double post, the board software seems to have eaten my last one. I'm curious about something regarding the Eemian as an analogy to a future warmer world. The Eemian was a period of the Green Sahara. "Approx. 125,000 - 120,000 y.a., moistest phase of the Eemian Interglacial (Isotope Stage 5e). Rainforest occupied a far greater area than at present, and rainfall was generally higher over north Africa. Data are sparse, mainly coming from long cores recording pollen and dust flux off the west coast of Africa. From these indicators, it seems that the situation generally resembled that of the early Holocene, around 8,000 14C y.a. General Eemian 'optimum' conditions in north Africa are summarized in map form by Frenzel et al. (1992) and by van Andel & Tzedakis (1996)." Africa during the early Holocene looked like this: http://www.esd.ornl.gov/projects/qen/NEW_MAPS/africa6.gif A good deal wetter than present Africa, apparently. But the IPCC predicts drying in tropical regions in a warmer world, as I remember. Why is this? Is it because the tilt of Earth's axis, orbit etc. were different in the Eemian? I also notice that from looking at paleoclimates warmer periods tend to be wetter. As I remember the IPCC projections are a mixed bag here, with drying in tropical regions and moistening in temperate ones. There are exceptions to the first (e.g. Mousterian Pluvial, US Southwest was wetter than the ice age), but the ice age tropics had less forest, Eemian tropical Africa had less desert, and as I remember from a paper I read on the Pliocene warm period Pliocene warm period Africa also had less desert. I'm getting most of my information from here: http://www.esd.ornl.gov/projects/qen/nerc.html#maps I'm not saying the IPCC's wrong, I'm just curious about the percieved difference. This site seems to have many knowledgeable people so I thought this might be a good place to ask about it. Also I just want to clarify I'm not saying I think this would mean global warming is a good thing or shouldn't be prevented. I wouldn't mind living in the world of the Eemian, it looks quite pleasant to me and more inviting than our drier and colder world, but putting our planet through a rapid change from present world to Eemian world while our present civilization is living on it does not strike me as a prudent plan. If recreating the Eemian world is possible and a good idea I'd much rather it happen as part of a managed and responsible geoengineering project by a wealthy and responsible future, not an out of control side effect of energy generation by the poor present, allowed to happen because of short-sightedness and apathy. I'm just interested in why the apparent difference between paleoclimate data and the projections happens. Thanks. An interested layman. -
okatiniko at 17:51 PM on 24 June 2011Sea Level Hockey Stick
"[DB] "There may be explanations for that, but perhaps not of the kind you'd like to hear." If, as I suspect, those "explanations" run afoul of the Comments Policy, then you would be correct." if comments policy forbids references to respectable, peer reviewed (but "disturbing") papers , yes.Moderator Response:[Dikran Marsupial] Judging by the abstract it looks off-topic for this thread. If you want to discuss it, pick a more appropriate thread.
[DB] For those interested, follow the links kindly provided by Pauls below. The RC discussion of the irredeemable issues with the von Storch paper are especially interesting. It is interesting (but tiresome) that some still trot out debunked and even rebunked papers in a transparent effort to dissemble and sow doubt.
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r.pauli at 17:25 PM on 24 June 2011Rogues or respectable? How climate change sceptics spread doubt and denial
You are too kind in your analysis. This may be delusional psychopathology. Or just a necessary coping mechanism. Denial defends the individual from ultimate shame and guilt. When one knows that carbon emissions directly cause warming then they know it can directly cause colossal damage of runaway warming. It is horrifying to bear the ethical burden of promoting an end to all civilization. Impossible to accept. Much easier to deny science and promote fantasy thinking than accept complicity. The self-destructive insanity of promoting delay and confusion, just means the consequences will be that much greater. And horribly, because of the increased consequences, it is a greater motive for more psychological denial. What a mess. Why do we pay attention to crazy people? This is not a test of science or logic, it is a test of the limits to human emotions. -
Berényi Péter at 17:20 PM on 24 June 2011Sea Level Hockey Stick
We can check it with the Interactive Sea Level Time Series Wizard of the CU Sea Level Research Group. Sand Point (A): 35.87N 75.64W - sea level rise (1993-2011): 0.0496 mm/year Tump Point (B): 34.99N 76.36W - sea level rise (1993-2011): 0.1049 mm/year These are satellite data, so sea level rise at the Atlantic coast of North Carolina is specified relative to the true geoid here. You can see current local rate (for the last two decades) is negligible. On the other hand if you check nearby tide gauges in the region, some show quite substantial rates of sea level rise for the same period, like the one at Hampton Roads (5.6 mm/year, close to Norfolk, Virginia). These rates are not measured relative to the geoid, but to local coastal elevation, therefore the difference is due to land subsidence. This rate is much higher than the (GIA related) secular rate specified by Kemp 2011 (0.9-1 mm/year). Recent acceleration of subsidence on the coastal plain is most likely due to groundwater depletion (sediment compactification occurs as pressure in coastal groundwater table is decreased by overexploitation). There is also a high local variability in this rate, because it depends on both nearby drilling history and structure of local layers at depth. Unfortunately Kemp at al. do not even try to address this effect. You can check the background in this USGS report: USGS - science for a changing world Professional Paper 1773, First posted November 8, 2010 Groundwater Resources Program Groundwater Availability in the Atlantic Coastal Plain of North and South Carolina Edited by Bruce G. Campbell and Alissa L. Coes This interpretation is consistent with the fact the bulk of local sea level rise acceleration (relative to coastal elevation) happened in the late 19th century, when industrial scale drilling for groundwater became feasible. It means Kemp at al. possibly detected a local signal unrelated to global sea level change, but caused by recent local anthropogenic effects on coastal elevation.
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