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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

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Comments 107851 to 107900:

  1. New temperature reconstruction vindicates ...
    I already have domestic solar but that's not the issue. The issue is large scale investment in such things, not small isolated individual investment. Even if governments just withheld the $500 billion a year going into antiquated FF industry pockets, that'd be a good start. And I'm not very keen on too much money going into power plants that need cooling water. Too many nuclear and coal plants are already having shutdowns at crucial times for lack of suitable, or any, water. Until we see good 20 year evidence of continual, reliable, non-flooding river flows at potential power plant sites I think nuclear's not a good option. Any generation.
  2. New temperature reconstruction vindicates ...
    KL writes: He just needs to find a fault in my maths, application of the first law, energy calculations, SLR calculations and a host of other numbers and logical points. Come on, Ken. The problems with this comment have been pointed out again and again. Specifically, you write If the Solar forcing curve were to start not at (0,0) but say (0.1W/sq.m, 0) - a slight positive forcing, then the extra area under the curve would be offset positively by 0.1W/sq.m x 260 years x 365 days x 24 hours x 3600 seconds x surface area of Earth; which equals approx 4190E20 Joules. Your idea here is that there is some unique "equilibrium" solar irradiance, such that any excursion from this value would lead to the Earth accumulating (or shedding) heat continuously at a rate linearly proportional to the magnitude of this excursion. With this model, a slight increase or decrease in TSI would (if sustained long enough) either heat the oceans to boiling, or freeze them solid. Fortunately, the real world doesn't do this. Instead, a small positive solar forcing would lead to an increase in temperature, which in turn leads to an increase in outgoing longwave radiation. At that point, the Earth and Sun are in a new equilibrium, with outgoing and incoming radiation balanced (and a slightly higher temperature for the Earth). At that point, the Earth stops accumulating joules ... unlike in Ken-world, where the unfortunate planet apparently keeps heating up forever. You seem to recognize the existence of the outgoing longwave radiation negative feedback when it comes to CO2 forcings. But your earlier comment includes no such effect for a solar forcing. Perhaps the earlier comment was just a youthful indiscretion? If so, it would help clear things up if you'd just retract it.
  3. Does Climate Change Really Matter?
    Daniel, Thank you for the references. I especially like Richard Alley's talk and Spencer Weart's article. I'm going to need some time to digest these articles.
  4. New temperature reconstruction vindicates ...
    adelady #137 M'lady - if you want all these things as we all do - I suggest you start investing in Geothermal, Nuclear (non-meltdownable of course), Hydro, Solar-thermal and possibly a little wind and PV Solar to warm the cockels.
  5. New temperature reconstruction vindicates ...
    Yooper #134 "You do yourself a great disservice by not reading your comments first for logical integrity before posting them." The point is obvious that warming will continue if there is a forcing gap. If warming is slowing (flattening), then the gap is closing. IR cooling is proportional to T^4 so rises faster than any of the CO2GHG forcings. To keep warming going at the surface you need positive WV feedbacks to rise and add to logarithmic CO2GHG forcing as rapidly as IR cooling so that the insulating (enhanced greenhouse) effect of the atmospheric column keeps increasing the T1-T2 temperature differential.
  6. New temperature reconstruction vindicates ...
    DB #135 Have a look at 'Robust Warming of Upper Oceans: http://www.skepticalscience.com/news.php?p=2&t=78&&n=202 BP#6, BP#16, KL#24, BP#30, KL#43 BP#45, BP#72 Conclusion: OHC since full Argo deployment in 2002-3 is pretty flat. Sharp jump prior to 2002 is an artifact of XBT - Argo transition - an offset error.
  7. New temperature reconstruction vindicates ...
    In fact it will continue to warm until the forcing gap closes and turns negative. And no-one ever said that warming will continue forever. After all, if we keep incinerating our grandchildren's grandchildren's inheritance those carbon sinks will eventually run out. Then things will change. Just how warm will it get before that turn to the negative? That's what all the concern and the science is about. Everyone knows that we'll have another ice age in a few thousand years' time. Everyone knows that our sun will die and our planet along with it in many millions of years' time. The concern is about life for this and the next half dozen generations of people. Not just life. Do we want to think of people struggling and barely surviving day to day or do we envisage thriving, successful communities? Communities with adequate power supplies and ample food and comfortable shelter and even some carbon fibre technology. Maybe an occasional surfing or skiing holiday for the lucky ones? Science is telling us we need to get our act together to ensure enough variety of carbon resources are left for those who follow us. We've had it easy. We know it will be harder for those who follow, but we have no good reason to make it near impossible for them. And there should be enough to extend our benefits to those who've been unable to share in them so far.
  8. New temperature reconstruction vindicates ...
    Yooper #131 Mighty generous of you to suggest: 'You are capable of being a valuable resource here, and elsewhere.' kdkd has made a point of shouting 'bollocks' to just about anything I suggest - because we have a jousting history elsewhere. This is the classic argument by intimidation. He just needs to find a fault in my maths, application of the first law, energy calculations, SLR calculations and a host of other numbers and logical points.
  9. New temperature reconstruction vindicates ...
    I note archisteel that you are not engaging on the numbers. There is a flattening of SLR, temperatures and probably OHC (although inadequately measured) over the last 10 years. Let's make sure we're on the same page here:
  10. New temperature reconstruction vindicates ...
    Re: Ken Lambert (133)
    "In fact it will continue to warm until the forcing gap closes and turns negative. Your huffing and puffing will not change the fact that the more accurate measurement has become in recent times - temperature, SLR and OHC by Argo - the flatter the rise in all three."
     In one breath you acknowledge the warming will continue and in the next you point to a not-statistically-significant-and-presumed-significant-because-I-don't-have-any-idea-why quasi-"flattening" of SLR (the short-term nature of which you also point out as being inadequately measured). You do yourself a great disservice by not reading your comments first for logical integrity before posting them. The Yooper
  11. What constitutes 'safe' global warming?
    I find the idea that we just allow ice to melt off Greenland and northern Canada in order to discover magically deep and fertile soil just ludicrous. Any soil that might be there will either be scraped off by the moving megatons of ice or washed away by the floods of ice melt. As for thawing permafrost regions, good luck cultivating soil that's releasing methane as you go. We'll need a whole new set of health and safety regulations for farm workers if anyone's mad enough to try. Any agricultural scientists on here able to tell us the likely effects on germination success and growth rates in such 'soils'? (Leave aside the chances of a whole crop being incinerated by someone accidentally igniting the methane.)
  12. New temperature reconstruction vindicates ...
    archisteel #130 And I am not really interested in whether or not you are interested in my offerings on these issues. kdkd and I have history elsewhere. Political arguments are not appropriate on this blog, and this is the great value of it. I note archisteel that you are not engaging on the numbers. There is a flattening of SLR, temperatures and probably OHC (although inadequately measured) over the last 10 years. This cannot be ascribed to ENSO, La Nina, PDO, AMO and other circulations and re-distributions of existing heat energy within the Earth system, unless we change our fundamental understanding that these complex circulations are not driven by external forcing imbalance. I have never claimed that CO2GHG do not contribute to increased surface warming by increasing the T1-T2 differential across the atmospheric column. I have claimed that the proportions of AG forcing and Solar forcing are not accurately known and that this is critical to predictions of the 'equilibrium' temperature rise. There is great uncertainty in the WV and ice albedo positive feedback and the cooling effect of cloud albedo. Relatively simple first law thermodynamics and heat transfer analyses can be made to check some of the claims of 'scientists'. Claims like 'hottest year on record' and 'hottest decade on record' are not inconsistent with warming being slowed or flattened or plateauing. If you climb a slope and reach a plateau you will be on the 'highest spot in your particular universe' until you climb down. In fact it will continue to warm until the forcing gap closes and turns negative. Your huffing and puffing will not change the fact that the more accurate measurement has become in recent times - temperature, SLR and OHC by Argo - the flatter the rise in all three.
  13. What constitutes 'safe' global warming?
    Re: chriscanaris (15)
    "It ultimately depends on whether we're looking at a CO2 forcing to equal the solar forcing of the Eemian. In the case of CO2 forcing, we're looking at concurrent H2O forcings and increased precipitation which could include increased snow cover in some settings (recall that Antarctica is the world's driest continent and hence there's some scope for negative feedbacks to GHG forcings in such settings)."
    In the case of glaciers, Greenland and Antarctica, recall that mass-gain occurs when snowfall increases in the accumulation zone outweigh losses in the ablation zone. When the sums are out of balance in the opposite direction, mass-loss occurs. This is what is happening right now. Yes, even in Antarctica. Even in the EAIS, in spite of increased snowfall in the accumulation zone, mass-losses in the ablation/calving zones are winning the struggle. The current levels of CO2 were matched last in the Pliocene (approximately 3 million years ago), when temperatures were at least 2-3 degrees C warmer than today (a level our current BAU track will allow us to attain or exceed). A look at those times reveals climate patterns unlike anything existing today. Given the absence of some magical unknown negative feedback mechanism to offset the increased CO2, we are faced with the prospect of the loss of the entire GIS and the WAIS (if one looks beyond 2100) and an attendant 20+ SLR (as the current linear SLR won't abruptly stop at the turn of the next century). In your Titanic analogy (updated): we've hit the berg and the ship is listing to one side, rendering half the lifeboats inoperable. Do we stop to fill and launch the remaining boats to allow some to survive? Or do we continue at flank speed & refill the ice in our drinks? The Yooper
  14. Climate Change: Past, Present, and Future
    As for batteries. It would be a great deal easier to just have drop off / drop in battery exchange stations, just as we already do for BBQ gas bottles. And a station with multiple recharging points would be an ideal first take-up arrangement for the kind of grid balancing arrangement we might end up with in places where wind is a signficant element in the power supply.
  15. What constitutes 'safe' global warming?
    RSVP, I suggest the exercise of signing a binding commitment allowing somebody or some semi-random process to pick a date anywhere from 50-100 years in the future, a date which will not be disclosed to you, agreeing that on that date you will allow yourself or your descendants to be forced-- regardless of whether you've had a change of heart-- to leave your worldly possessions behind and quickly move somewhere else, a place that does not yet have a name or functioning economy. The commitment should entail that you or your descendants will be accompanied by a substantial collection of strangers collected from different parts of the world and of course you'll want to coexist with your new neighbors in peace and harmony regardless of accompanying cultural baggage of the portable religious, moral and ethical style. Alternatively, you could modify the binding agreement to entail that you wait until some bit of naked rock is exposed on the southern coast of Greenland, then take all of your worldly possessions and your family and move there in a more orderly fashion and proceed to carve out an existence. The commitment should require that you pick a date 50-100 years in the future, and again it will be enforceable on your descendants. Also, there will unfortunately be no means of picking your neighbors, as in the first example exercise. Does being a refugee sound good? Are you happy with facing a myriad of unresolved details each of which is crucial to your continued well being? Does taking on a load of uncertainty making the IPCC synthesis appear like 2+2 sound like an attractive proposition?
  16. Uncertain Times at the Royal Society?
    Baz, Hazlitt wasn't a scientist, and I imagine he was responding as a philosopher to the fundamental shift taking place at the time from God (the external) to Reason (the internal). These days, science is performed ultimately in order to predict. Read the discussion section of any peer-reviewed, published report from the sciences. You say that science is a long way from being never certain. What the heck does that mean? I take it you're trying to say that climate science has a low degree of certainty about . . . about what? About the physics of C02, CH4, and H20? Very, very high probability. About the energy budget? Very high probability. Where is the lack of confidence you're referring to? Science doesn't say, "There can be only one." Science says, "No other explanation makes as much sense when read against the physics and the data."
  17. Climate Change: Past, Present, and Future
    doug, you make good points about cost constraints. I'd be willing to pay the extra amount to avoid gas stations most of the time, but that isn't universal. Hopefully there will be enough people who drive less than 40 miles per day on average for the Volt design to really take off and thereby help push changes. adelady, yes there are alot of benefits to electric cars even with current infrastructure. I was talking more about getting people to buy the cars. For instance, the 100 mile Leaf... if you have to go more than 100 miles you want to be able to find a charging station somewhere along the route. Right now chances are you won't. Even if you do you'll be charging for hours rather than stopping a couple of minutes for gas... unless we develop faster charging technology. Also, battery life is still an open question for all of these cars, but we know it will degrade over time... so that 100 miles may become 80 or 60 and replacement costs could be prohibitive. Et cetera. There are limitations which will prevent alot of people from using electric vehicles right now. All of them seem possible to overcome, but that won't happen so long as most driving is still done via gasoline.
  18. Eric (skeptic) at 23:51 PM on 4 October 2010
    Newcomers, Start Here
    This post is much better than the original due to a broader perspective that includes hunting. I have a modest request for the intermediate version: links about the causes of cub mortality (which may include the female weight loss). Aside from hunting, cub mortality appears to be the crux of the issue of population stability.
  19. What constitutes 'safe' global warming?
    16: "even though the "intellecual" theory dictates that temperature changes as the log of GHG concentration." Over the range of 280
  20. What constitutes 'safe' global warming?
    RSVP #13: "For this worse case scenario, has anyone demonstrated that there will actually be less habitable land as sea level rises? Shouldnt all kinds of land tracts be getting freed up of ice compensating loss of coastal regions?" Ummm... no. Not even close. The amount of land occupied by ice outside of Greenland and Antarctica is negligible and all at high altitudes which are sparsely settled to begin with. Whether Greenland will gain land from ice loss faster than it loses land from sea level rise is an interesting question, but it certainly won't outpace the rest of the world combined. Antarctica, of course, will remain uninhabitably cold unless temperatures rise so much that much of the rest of the world becomes uninhabitably warm. #16: "Is "pre-industrial" before or after the invention of the thermometer?" The thermometer predated the industrial revolution by a couple hundred years. "...temperature changes as the log of GHG concentration." No. Radiative forcing changes with the log of GHG concentrations. Temperature changes with the radiative forcing, climate sensitivity, and time.
  21. An underwater hockey stick
    TOP: Do you have data for deeper waters or waters in tectonically active areas? Are you aware of any papers? If you're constructing an alternative hypothesis about why the oceans are warming, it's incumbent on you to find information lending support to your hypothesis, not everybody else. It's odd, how frequently we have skeptics saying words roughly along the lines of "But this other thing might be happening, and you can't show otherwise until you've found the information I've not provided to support my hypothesis." TOP, there's scads of literature on heat flux at the bottom of the ocean. Go look at it, bring us the pleasant surprise we're all hoping for.
  22. What constitutes 'safe' global warming?
    RSVP #14, very naif and meaningless comment. Does anyone count on the right outcome from a wrong action? You need to be very lucky ... A brake is a brake, if you push the wrong pedal it's not a brake. As easy as this. I'd love to read more thoughtful comments here at SkS.
  23. What constitutes 'safe' global warming?
    "For this worse case scenario, has anyone demonstrated that there will actually be less habitable land as sea level rises? Shouldnt all kinds of land tracts be getting freed up of ice compensating loss of coastal regions?"
    How much arable land will there be at high altitude? Is it cheaper to build towns and cities on crags or on flatlands? As ever, it is not the change so much as the rate at which it occurs that will yield the cost. 2C over a thousand years is a much more manageable impact than 2C over a century.
  24. Climate Change: Past, Present, and Future
    Massive infrastructure changes? I already thought of cars when I read about a wind generation problem in Germany. They're actually paying some people to leave lights on all night when the turbines are putting in more power than is needed. If cars or other battery storage facilities were recharged at low use periods, there's no reason why the recharge shouldn't be overridden - on or off - depending on imbalance in turbine output and network requirements. Cars, buses and other equipment could function as a network equaliser. Neat, huh?
  25. Climate Change: Past, Present, and Future
    CBD, certainly it's possible to "build a car with ~100 mile electric range AND a backup gasoline powered electrical generator" with today's technology. GM is doing -almost- exactly that, with the difference their offering "only" goes 40 miles on batteries at the modeled fleet end of life. The challenge of the next 60 miles is primarily money, not technology, plus a bit of the same physics rocket scientists face. Leaving aside the lunatic marketers responsible for the soccer-moms-and-accountants-in-work-trucks fad, GM is actually quite good at figuring out how to build things that are affordable for their market. Especially they're good at looking at what happens when they have to make a lot of copies of a product. Given some fairly tight prognostication on constraints and limits of future battery costs, GM has found that adding 60 miles of battery range to the Volt while leaving their rather nicely implemented gasoline-electric drive train in place will push the Volt's price up in a way that leaves it far outside the price range even of most "early adopters," with little prospect for a decline to realistic levels. Remember, to be useful these cars have to go beyond the boutique, they've got to slip into a family budget as a drop-in replacement. Also, as with rockets, the more potential energy stored, the less efficient the vehicle becomes for its primary requirement, delivering payload. All this w/-present- technology, mind. The world of electrochemistry still continues to deliver surprises.
  26. Irregular Climate podcast 11
    chriscanaris #25, without an ice free Arctic, oil drilling in the region would be impossible... and I'm not talking about just part of the year. If the water around an oil rig were to freeze into ice several meters thick that rig would be badly damaged and immediately begin leaking oil. Note that all of the exploratory wells being dug are in areas that have been ice free year round for decades now. And even there they've got tug boats on call to divert icebergs away. In short, the only way any of these countries are going to be drilling for oil in the Arctic basin is if the ice melts out year round... something which won't happen for decades yet under the worst case estimates. Based on IPCC 4 it'd be at least a couple hundred years. Yet there is a race on now to lay claim to these future mineral resources. Which ought to indicate pretty clearly that they know IPCC 4 was hugely conservative and the Arctic sea ice is not 'recovering'... as claimed by some of the very same politicians pushing for Arctic oil exploration.
  27. Uncertain Times at the Royal Society?
    Baz #94: "What else could have caused a fairly-sharp upturn in temps?" Increased solar radiation could have... but didn't, because solar radiation actually decreased over that timeframe. A massive change in cloud cover could have... but didn't, because cloud cover was largely unchanged. Dropping from a highly active volcanic period to low volcanism could have... but didn't, because we've been in a period of low volcanism the whole time. Et cetera. Anything which logically (and even ILlogically, c.f. 'cosmic rays') could have caused the warming has been examined and found not to be the case... except that the increase in atmospheric concentrations of greenhouse gases absolutely should have caused a sharp upturn in temperatures... which did in fact occur.
  28. Uncertain Times at the Royal Society?
    sime, or... "Science is the desire to know causes" - William Hazlett
  29. An underwater hockey stick
    Top #33: "The anomaly in the water temps is larger than that in the atmosphere. It is the driver." Given that more than 90% of the enhanced greenhouse warming accumulates first in the oceans your statement above is obviously true... but your apparent conclusion that this means the oceans are somehow 'generating' the increased temperature is clearly illogical. If this were simple a matter of heat being transferred from the oceans to the atmosphere then we ought to be seeing ocean temperatures falling while atmospheric temperatures increase. Instead BOTH are increasing. That unquestionably indicates that some external factor, in this case an enhanced greenhouse effect, is causing warming to both. #46: "What this paper opened up is the possibility that a ocean heat transport has melted the arctic ice from below." We have known for some time now that most of the recent Arctic sea ice decline is due to increased ocean temperatures. Indeed, ocean warming is also believed to be responsible for much of the observed loss of land ice from Greenland and Antarctica. Again, this is due to the oceans absorbing additional radiation from the enhanced greenhouse effect... not some form of 'spontaneous ocean heating'.
  30. Climate Change: Past, Present, and Future
    GC #60, "I would like to set you straight but that would get us into the realm of "solutions"." Solutions are bad? Political arguments are to be avoided, but reality based solutions are fine. On the whole 'electric auto' front... I'm not looking to trade in my 2001 Prius yet because I drive more than the Leaf's 100 mile range several times a year and more than the Volt's 40 miles electric range every day. The 200+ mile range of the Tesla Roadster would be enough... but it's a ridiculously ostentatious 'look at me' mobile. Given current technology it ought to be possible to build a car with ~100 mile electric range AND a backup gasoline powered electrical generator. That would allow 99% of the drivers in the world to complete their daily commute on electric power. People would only ever need to put gas in their tank for the few trips a year (if that) where they were going further. No 'range anxiety' problems and gasoline usage cut to an insignificant fraction of current... yet nobody seems to be building such a car. Instead we've got all electric or electric with gasoline backup, but too short an electric range to ever leave the gas tank empty. Sure, going directly to all electric would be great... but realistically it isn't going to happen without massive infrastructure changes. A 100 mile electric / gasoline hybrid could get us most of the way to zero gasoline usage NOW. No waiting on a network of charging stations, faster charging battery technologies, batteries that don't deteriorate as much over time, and/or batteries with higher energy density... all of which would also get developed much faster if electric powered driving were already predominant due to hybrids. Thus, I see well designed hybrid cars (not the illogical designs we're getting now) as a stepping stone getting us to an all electric infrastructure much faster than we would without them.
  31. Uncertain Times at the Royal Society?
    And today's thought for the day is... "What's the use of having developed a science well enough to make predictions if, in the end, all we're willing to do is stand around and wait for them to come true?" -- Nobel Laureate Sherwood Rowland (referring then to ozone depletion)
  32. Uncertain Times at the Royal Society?
    Hello all. 30 to 35 years ago something appears to have happened to global temperatures. Indeed, that is even refected locally here in the longest dataset we have: http://hadobs.metoffice.com/hadcet/graphs/HadCET_graph_ylybars_uptodate.gif Even in the Arctic, a period of 30-35 years of gradual ice-extent loss seems again evident. Only the Antarctic shows no sign of a similar change (and a number of temp recording stations around the world). Given that science is never certain, and climate science falls a long way short of that, and if you can suspend your belief that the principle cause of this is/was man-made, what else could it be? What else could have caused a fairly-sharp upturn in temps?
  33. An underwater hockey stick
    Scaddenp Do you evaluate basins like this? I would think that borehole data on really deep water is missing. Deep water is is 1 mile these days AFIAK and in fairly stable areas. Do you have data for deeper waters or waters in tectonically active areas? Are you aware of any papers? I agree with very cold, the paper stated that temps in the area in question was around 4C.
  34. An underwater hockey stick
    When you overlay two graphs with dissimilar axes you have to rescale one or the other so they match. You also have to shift the zeros. Basic graph handling skills. Here it is. Pretty ugly but it gets the point across. Atmospheric "hockey stick" from IPCC as posted on wikipedia. Overlay The principals of heat transfer have been peer reviewed for hundreds of years. You have three choices:
    • Conduction slow not likely in liquids and gases
    • Convection rapid can transport vast amounts of heat very likely in gases and liquids not particularly dependent on the nature of the materials
    • Radiation speed of light very particular about the nature of the materials occurs at interface of two bodies separated by relatively free space, does not occur inside solid or liquid matter to as great a degree as in gases or vacuum
    • Phase Change As an adjunct to convection can transport orders of magnitude more energy than storage by temperature change alone. Transport of heat to the upper troposphere by phase change of water comes to mind.
    Since the water where these cores were taken were, as the paper points out, are relatively well insulated from surface effects (radiation, conduction from atmosphere) you have convection (which can be horizontal if by currents) and conduction from below. These water temperatures were also localized. We just don't have enough of these temperature measurement to make global statements. I believe we had some information about anomalies in the Southern Ocean Basin a few days ago. The same concerns apply there. What this paper opened up is the possibility that a ocean heat transport has melted the arctic ice from below. Remember, "science tends to be self correcting."
  35. What constitutes 'safe' global warming?
    Chris, Keynes dictum is about _current_ affairs. When we're talking about warming and disruption, I actually care quite a lot about what my descendants may face long after I'm dead. I can't save them from failed love affairs or worries about passing exams. But I can be part of an effort to ensure that they get the best possible chance of living in a world that's congenial to healthy life and not torn by strife over inadequate water, food or living space. I'm not asking for utopia. Life is always difficult and dangerous. I lived through polio epidemics and the cold war and several other wars. Our generation has the opportunity to try and avoid making life more difficult and dangerous than it need be for our grandchildren's grandchildren.
  36. What constitutes 'safe' global warming?
    "...global temperatures have warmed around 0.8°C from pre-industrial temperatures" Is "pre-industrial" before or after the invention of the thermometer? Continutin... the link in the first sentence, takes you to a past article that starts... "Unfortunately, the discussion went pear shaped with some ideological anti-intellectualism " The word "anti-intellecutalism" in turn links to yet another article that contains the proverbial graph wherein CO2 and temperature track perfectly one on the other given two linear scales that are selected for this purpose, even though the "intellecual" theory dictates that temperature changes as the log of GHG concentration.
  37. What constitutes 'safe' global warming?
    *@#! those links! Make this the final version and feel free to delete the others. John, I take your point about the Eemian period, which seems to have been a predominantly solar based event. Actually, being on the real Titanic would serve as a better analogy for the point you're trying to make. Ironically, because its electrical power plant functioned until the very end, many passengers were reluctant to disembark from the seeming comfort and safety of a well-lit ship. Interestingly, the Titanic was designed to float with the first four compartments flooded. Instead, the glancing blow to the starboard side caused buckling in the hull plates along the first five compartments, more than the ship's designers had anticipated. Coming back on topic, I looked at earlier posts on ice loss which seems to be the real polar bear in the room. It ultimately depends on whether we're looking at a CO2 forcing to equal the solar forcing of the Eemian. In the case of CO2 forcing, we're looking at concurrent H2O forcings and increased precipitation which could include increased snow cover in some settings (recall that Antarctica is the world's driest continent and hence there's some scope for negative feedbacks to GHG forcings in such settings). Coming back to the Titanic analogy, we don't really know whether we're flooding five compartments or four. In the former case, we would be silly to clamber into the lifeboats. In the latter, we can take cold comfort from Keynes dictum: 'The long run is a misleading guide to current affairs. In the long run we are all dead.' He also said: 'When the facts change, I change my mind. What do you do, sir?'
  38. What constitutes 'safe' global warming?
    #10 "I think that the real question is "how hard can we push the brakes?". If you are pushing the wrong peddal, it wont make any difference.
  39. What constitutes 'safe' global warming?
    #12 "We're doomed! " For this worse case scenario, has anyone demonstrated that there will actually be less habitable land as sea level rises? Shouldnt all kinds of land tracts be getting freed up of ice compensating loss of coastal regions?
  40. What constitutes 'safe' global warming?
    Most scenarios only go as far as 2100AD, but these all show the temperature still rising at a considerable rate. Ultimately the increase looks like being much more than 2C, even with the most optimistic model. We're doomed!
  41. An underwater hockey stick
    Bibliovermis, forgive me if I misunderstand your question. The heat being transported in THC is solar radiation warming tropical water and transporting it about the globe. The idea that heat is from the inside the earth can be readily dismissed. The bottom waters are dense and cold. We measure that. The heat flux from inside earth to surface is also measured from boreholes - routine part of petroleum basin evaluation these days (and part of my job). At around 40-80 milliwatts/m2, this is inconsequential compared to the 190 watts/m2 from sun.
  42. Climate Change: Past, Present, and Future
    gallopingcamel wrote : "Most of the time I am flying against the wind on this blog and the faithful are used to applying ritual flagellation." Do you see everything in life in religious terms ? I suggest you should lean less on religion and more on science, when it comes to AGW at least.
  43. What constitutes 'safe' global warming?
    chriscanaris: "So John, I wonder whether we really should be talking about rises of 6 - 9 metres. I do agree however that two metres would definitely be a worry." 1 metre would cause many problems at Portsmouth UK, at high tides. 2 metres would cause flooding in some places. Portsmouth is densely populated, so many homes would be at risk at regular flooding. 3 metres would result in the Millennium tower to be closed regularly and some parts of the island to be un-inhabitable. 4 metres would be very difficult to defend against, probably leading to serious plans for moving the 200,000 population onto new homes and towns on agricultural land. Although I suspect at 3 to 3 metres plans would already be in place. 5 metres would mean abandonment of the city. About half of it is below 5m, certainly not higher. 6 metres ... There would be the question of pollution, due to land fill and materials from buildings being flooded. I guess that would be planned as well. Total costs would be billions probably just for one city and a loss of farmland to home the displaced. The surrounding coastal area would also be affected, with similar evacuations and loss of farmland and other green spaces.
  44. An underwater hockey stick
    archiesteel at 14:52 I shall attempt to... if this works this is just the top one dropped on top o the bottom one, not rescaled on the Y axis, for obvious reasons... The THC is thermohaline circulation. A major ocean current, that basically pumps energy from the equator to higher latitudes. montage Bibliovermis at 14:58 I think you will find, that, that giant fusion furnace in the sky is responsible for the VAST majority o the energy in the climate system, not the fission one under your feet. An obvious point, would be the lack of documented oceanic convection...
  45. What constitutes 'safe' global warming?
    Actually, I'm very pragmatic on this issue. Taken for granted that we're already outside the safe operating space on a few systems, I think that the real question is "how hard can we push the brakes?". Politically we need to define a threshold (a goal) and 2 °C is a good one, but I do not put much value on it. Indeed, I believe that we will push the brakes anyhow and we've started doing it, although not that hard yet. Like it or not, the fossil fuel era will (relatively) soon come to an end and the very long term impacts will be avoided. I can't speak for John, but this is my take on this post.
  46. Climate Change: Past, Present, and Future
    @gc (#62): "Actually, the electric automobile was developed first but somehow the internal combustion engine has gained a temporary ascendancy." Indeed, at some point electricity, steam and internal combustion all competed. The main reason the latter won is that it was much easier to set up a gasoline distribution network (i.e. gas stations and trucks) throughout the US than have an electric power grid covering the majority of such a vast therritory (unlike what we have now). Steam engines used coal, so you can imagine what that would have done for pollution... :-)
  47. What constitutes 'safe' global warming?
    chriscanaris, "wonder whether we really should be talking about rises of 6 - 9 metres." It depends on our ability to discriminate between different time frames.
  48. What constitutes 'safe' global warming?
    From http://www.nature.com/climate/2010/1004/full/climate.2010.30.html">Lowe and Gregory in Nature Reports 2010: 'New research suggests that the possibility of sea level rise of up to two metres by 2100 should be given serious consideration. One key study examined the ice flow rates that would be required to produce substantial sea level rise by 2100 and concluded that a rise of much more than two metres would be “physically untenable” [which is from the Pfeffer 2009 abstract verbatim]...Proxy evidence from oxygen isotope ratios in Red Sea sediment cores6 suggests that sea level rose by as much as 1.6 metres per century at a time in the past when the large ice sheets covered an area similar to their present-day extent...Although increases of up to two metres this century can't be ruled out, this does not mean that they are inevitable or even likely. For climate change to produce much more than one metre of sea level rise, ice sheets would probably have to contribute considerably more to the rise than they do now... The recent acceleration of Greenland outlet glaciers and Antarctic ice streams [this is a reference to Velicogna’s GRACE study of 2009] may be due in part to natural variability, and it might not continue. Some observations indicate that a number of the outlet glaciers and ice streams that accelerated in the 1990s have since started to slow down... In this sea of uncertainty, how do we derive a better estimate of sea level rise? ...The [current semi-empirical modelling] approach is loosely based on an understanding of physical processes, but the relationship is determined by statistical methods. The general assumption is that the relationship between sea level rise and temperature (or forcing) will hold in the future and for a much greater range of warming than occurred during the period from which it was calibrated... There has already been some debate about the statistical validity of these approaches... Adding up the estimates of the various observationally derived contributions to historic sea level rise, which all have uncertainties, we find that their sum may fall short of the measured total sea level rise... The semi-empirical methods assume that any difference is due to a missing contribution that will increase with global warming. Though that assumption may be correct, without understanding/ identifying the physical processes that may make up this shortfall in sea level, there is little in the way of supporting evidence.' The ellipses are in the interests of attempted brevity. Lowe seems to have made a major contribution to the UK defra site which concludes: *Our analysis gives projections of UK coastal absolute sea level rise (not including land movement) for 2095 that range* from approximately 13–76 cm. *Taking vertical land movement into account gives slightly larger sea level rise projections relative to the land in the more southern parts of the UK where land is subsiding, and somewhat lower increases in relative sea level for the north. We have, for example, derived projected relative sea level increases for 1990–2095 of approximately 21–68 cm for London and 7–54 cm for Edinburgh (5th to 95th percentile for the medium emissions scenario). *A low probability High++ sea level range has been defined for vulnerability testing. For the UK this absolute SLR estimate is 93 cm to 1.9 m by 2100. In the case of recent iconic flooding such as Hurricane Katrina in New Orleans, we find that much of the problem emanated from the fact that some 49 percent lies below sea level, in places to 10–12 ft (3.05–3.66 m)- a problem compounded by subsidence of reclaimed land. I leave aside the contentious question of whether Katrina like events are more likely - I think they belong on another thread. So John, I wonder whether we really should be talking about rises of 6 - 9 metres. I do agree however that two metres would definitely be a worry. Similarly, I really have no way of knowing whether Lowe and Gregory's take on Velicogna is overoptimistic.
    Response: Thanks for that link, Chris. The Nature commentary doesn't, however, touch on empirical determinations of Eemian sea levels. Instead, it looks at semi-empirical attempts to predict the trajectory of sea level rise over the next century. As I say above, there's uncertainty about the time-frames involved.

    But the end destination, 6+ metres sea level rise under sustained temperatures 2 degrees warmer than pre-industrial levels, is determined empirically and independently of the methods discussed in the Nature commentary. I liken it to watching James Cameron's Titanic. We know how it ends but we're not exactly sure what's going to happen along the way and whether Leonardo di Caprio gets offed or not.
  49. Climate Change: Past, Present, and Future
    Re: gallopingcamel (62) My apologies for being less than clear with my comments about the development of the electric auto. I should have said something along the lines of "If the electric auto had achieved widespread market penetration before the development of the internal combustion engine...". Thanks for the additional background info. If an electric car could put up with the deep snows of winter and the 200-250 miles per day work entails, I would have one instead of my Jeep Patriot POS 'fine example of American engineering' my company furnishes me with. FYI: It IS possible to fly against the wind without drawing flagellating fire, depending upon the idiom employed. :) The Yooper
  50. New temperature reconstruction vindicates ...
    To be fair KL and I have history, and in places other than this one, I have been exceptionally rude to him (and him to me). I won't link to the examples as that would be against the comments policy. Let's just say that "repetitive rubbish" is a more polite version of a particular name which I have called him elsewhere. To Ken's mind my impatience with his repetition is unacceptable. Instead I think he considers that we should accept his argument's validity because he's repeated it so often. It's worth noting that Ken's argument remains unchanged in nearly 18 months, despite a range of people pointing out to him the fatal flaws with his argument with varying degrees of civility.

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