Recent Comments

Prev  1625  1626  1627  1628  1629  1630  1631  1632  1633  1634  1635  1636  1637  1638  1639  1640  Next

Comments 81601 to 81650:

81601. Eric the Red at 01:55 AM on 25 June 2011
       Websites 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.
81602. Eric (skeptic) at 01:51 AM on 25 June 2011
       Websites 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.numbers
       Moderator 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.
81603. JMurphy at 01:15 AM on 25 June 2011
       Renewables 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.
81604. dorlomin at 01:06 AM on 25 June 2011
       A Detailed Look at Renewable Baseload Energy
       Great article, lot to digest.
81605. rcglinski at 00:57 AM on 25 June 2011
       Renewables 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.
81606. J. Bob at 00:37 AM on 25 June 2011
       Sea 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.
81607. JMurphy at 00:34 AM on 25 June 2011
       Websites 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.
81608. Eric the Red at 23:53 PM on 24 June 2011
       Websites 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?
81609. JMurphy at 23:50 PM on 24 June 2011
       Linking 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
81610. Tom Curtis at 23:50 PM on 24 June 2011
       Sea 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.
81611. Ken Lambert at 23:41 PM on 24 June 2011
       Sea 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
81612. Ken Lambert at 23:32 PM on 24 June 2011
       Sea 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.
81613. CBDunkerson at 23:18 PM on 24 June 2011
       The 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.
81614. Argus at 23:14 PM on 24 June 2011
       Sea 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)
81615. pauls at 22:53 PM on 24 June 2011
       Sea 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.
81616. Marcus at 22:36 PM on 24 June 2011
       IPCC 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!
81617. skywatcher at 22:31 PM on 24 June 2011
       Sea 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...
81618. sgmuller at 22:30 PM on 24 June 2011
       Rogues 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."
81619. skywatcher at 22:21 PM on 24 June 2011
       Websites 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.
81620. Rob Painting at 22:18 PM on 24 June 2011
       IPCC 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.
81621. Marcus at 22:12 PM on 24 June 2011
       IPCC 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?
81622. Marcus at 22:02 PM on 24 June 2011
       IPCC 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?
81623. Rob Painting at 22:02 PM on 24 June 2011
       The 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.
81624. Dikran Marsupial at 21:48 PM on 24 June 2011
       Sea 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.
81625. Tom Smerling at 21:46 PM on 24 June 2011
       IEA 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.
81626. Papy at 21:43 PM on 24 June 2011
       French 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)".
81627. Tom Curtis at 21:29 PM on 24 June 2011
       Sea 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.
81628. Eric the Red at 21:22 PM on 24 June 2011
       Sea 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?
81629. Steve Brown at 21:15 PM on 24 June 2011
       The 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.
81630. Eric the Red at 21:07 PM on 24 June 2011
       The 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.
81631. Eric (skeptic) at 21:04 PM on 24 June 2011
       Linking 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
81632. michael sweet at 20:58 PM on 24 June 2011
       Websites 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.
81633. Eric the Red at 20:45 PM on 24 June 2011
       Linking 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.
81634. michael sweet at 20:17 PM on 24 June 2011
       Linking 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.
81635. JMurphy at 20:06 PM on 24 June 2011
       IPCC Report on Renewable Energy
       And offshore wind requires no land !
81636. LochNess at 19:50 PM on 24 June 2011
       The 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...
81637. Argus at 19:05 PM on 24 June 2011
       Sea 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.
81638. Somes_J at 18:22 PM on 24 June 2011
       The 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.
81639. Somes_J at 18:19 PM on 24 June 2011
       The 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.
81640. okatiniko at 17:51 PM on 24 June 2011
       Sea 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.

81641. r.pauli at 17:25 PM on 24 June 2011
       Rogues 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.
81642. Berényi Péter at 17:20 PM on 24 June 2011
       Sea 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.
81643. Tom Curtis at 16:35 PM on 24 June 2011
       Linking Extreme Weather and Global Warming
       Norman @189, your are correct that there was a discrepancy, and my second post was exaggerated. Never-the-less, your practical definition of "disaster" is far too restricted, at least as used in your post 154. In particular, you say there where "3 tornado disasters", and that "In 2011 with 80 F3 or above tornadoes you have 6 tornadoes of this magnitude that caused disaters and a total of 9 tornadoes that struck cities". In fact in the 1974 outbreak there were tornado related deaths in 64 different counties, and nine "most significant" tornado incidents, Xena (death toll - 34), Brandenburg (31); Lousville (only 2 killed, but over 200 injured and 900 homes destroyed); De Pauw and Madison (17 killed, 375 injured); Cincinnati/Sayler Park (3 killed and over 100 injured); Monticello (19 killed); Tanner (50 killed, over 400 injured); Jasper, Guin and Huntsville (3 killed and over 150 injured); and Windsor, Canada (9 killed, 20 injured). So, my first point is that in counting only three tornado disasters in 1974, you are using far too high a standard for the damage/injury or death level needed to categorize a tornado as a natural disaster. Actually, in the Munich Re data the entire outbreak and all its tornadoes may well count as just one disaster, and the many seperate outbreaks in 2011 also each count as one disaster regardless of the number of tornadoes spawned in each outbreak. But ignoring that subtlety, there where at least nine, and probably more than 30 distinct disasters in that one outbreak. (Some tornadoes crossed more than one county, and one crossed three states, so I cannot give an exact count.) My second point is that each of the three most deadly tornadoes listed above was an F5, and nearly all were F4 or F5, with only the Windsor tornado being F3. Therefore the F3 tornadoes are irrelevant to the comparison you actually made. Note carefully, irrelevant for the comparison, and most certainly not irrelevant on the ground. So if you only wish to count the three worst incidents in 1974, then you should restrict the discussion to F4 plus tornadoes, and in that case 1974 and 2011 have very similar numbers. What is more, in 2011 just two tornadoes caused thirty or more deaths, your apparent benchmark for significance in 1974. So, while I acknowledge and apologize for my error in post 164, I believe my logical points stands unrebutted
81644. ginckgo at 15:58 PM on 24 June 2011
       The chief troupier: the follies of Mr Monckton
       beastie @ 5: The majority of the world's coal deposits were formed during the Late Carboniferous (Pennsylvanian) and Early Permian. During these periods the atmospheric CO2 content was about what it is today, and the world was in the longest Ice Age of the Phanerozoic. How does that reconcile with the assertion that during high CO2 times plant productivity will be higher, when we have this geological evidence that appears to indicated the opposite is true (there are more factors than CO2 involved, obviously). Petroleum on the other hand often comes from source rocks that were laid down in Greenhouse climates; but these are all marine sediments, and the organic content preserved so well because the oceans were stagnant and huge dead zones covered the ocean floor allowing the carbon to accumulate (but that's not a happy ocean from our perspective).
81645. R. Gates at 15:36 PM on 24 June 2011
       The Last Interglacial - An Analogue for the Future?
       This will be an interesting series to follow. A few thoughts: While it is interesting to compare two different interglacials, and certainly both can be traced back ultimately to Milankovitch cycles, I would think that comparing CO2 levels and anticipated effects might yield some very sketchy projections. Rising temps during interglacials probably begin a positive feedback process with outgassing of CO2 from the oceans leading to more warming etc., but the sudden anthropogenic burst of CO2 during this interglacial to far higher levels than the past several interglacials should create a completely different dynamic, as the ocean themselves have not warmed enough to have released a similar amount of CO2...i.e. we are heading closer to what we saw in CO2 levels during the PETM but ocean temps are currently cooler. So, as oceans warm and begin to become net producers of CO2 from outgasssing rather than the large CO2 sink they been, it's possible we could see a sudden jump in the annual rate of CO2 growth, far larger than the annual increase from anthropogenic sources alone. This would be a far different dynamic than the last interglacial and would likely lead to all sorts of other very different climate dynamics. I certainly look forward to the rest of this series...
81646. okatiniko at 15:24 PM on 24 June 2011
       Sea Level Hockey Stick
       #39 : "@okatiniko. What do you mean? without any clear signal...? Can it be any clearer? " The signal is very clear after 1900, but there is nothing conspicuous associated with the supposed anthropogenic component after the 60's. This is very usual in all proxy-based reconstructions : they don't show anything clearly associated with the rise of anthropogenic forcings, only with the exit from LIA in the XIXth century - or maybe simply correlated with the advent of modern instrumental methods, allowing the proper calibration of data. There may be explanations for that, but perhaps not of the kind you'd like to hear.
       Response:

       [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.

81647. Camburn at 14:53 PM on 24 June 2011
       Linking Extreme Weather and Global Warming
       DB: On this one I have to disagree. Where I live, ND, when we have a mild winter we, as a rule, have less snow. This past winter was the 13th coldest on record, and if memory serves me, the 6th snowiest on record. We can have -20F temps, then the temp rises and it will snow. After the front has passed, it will cool off again to the normal cold. A local observation of what happens here.
81648. J. Bob at 14:47 PM on 24 June 2011
       Sea Level Hockey Stick
       Sphaerica @49, Perhaps you didn’t get the point. The initial point was to compare tidal measurements on the E & S coasts of the US, with global temperature. That is, get a broader surface sample of readings. Then compare the filtered results to see if there is any significant correlation. And from the graph, it was found that the station data was pretty close to the trend line, and did not have the changes ( i.e amplitude and/or phase), noted on the global temperature plot. That just might give a indication of temp & sea levels not being correlated that well. ( -Previously posted linked graphic snipped- ) The second was a matter of interest, as to NH temperature being correlated to long term temperature records. Since the issue of conflating regional data to global data came up, here is a updated chart comparing long term European data with HadCRUT NH & global data. It would appear there are strong correlations between the temperatures, but not with the CO2, similar to the tidal data. ( -Previously posted linked graphic snipped- ) And I will agree, there can be problems with conflating information, one has to be careful on what your doing. So one can make the case that a correlation between sea level an global temperatures is about as bad as between global temperature and CO2. Perhaps you could "cobble" something better, to convince me otherwise?
       Response:

       [DB] Links to graphics you had previously linked to in your comment at 48 earlier snipped.  Please just refer back to the earlier post with a link to it.  Repeating yourself doesn't gain you extra credit.

81649. scaddenp at 14:41 PM on 24 June 2011
       Sea Level Hockey Stick
       If you made some effort to understand the link between regional and global sealevel, you would make more sense. Hint the "10cm error bar" doesnt mean what you think it does.
81650. Camburn at 14:29 PM on 24 June 2011
       Linking Extreme Weather and Global Warming
       Must be a difference in the climate. Whenever it snows here in the dead of winter it always warms as it snows and then gets colder again. That is about the only reason to look forward to snow as the temp moderates.
       Response:

       [DB] "Whenever it snows here in the dead of winter it always warms as it snows and then gets colder again."

       That's because here in the north where we live the snowfall event is usually quickly followed by very cold Arctic air masses that move down out of Canada.  Clear skies at night allow the warmer air held nearer the ground by the clouds delivering the snowfall to then escape, leaving the surface air much colder than it was previously.

       Which is why there is less precipitation in the colder winters and more in the warmer winters here.

       This is all very basic, basic stuff.

Prev  1625  1626  1627  1628  1629  1630  1631  1632  1633  1634  1635  1636  1637  1638  1639  1640  Next