Recent Comments

Prev  1565  1566  1567  1568  1569  1570  1571  1572  1573  1574  1575  1576  1577  1578  1579  1580  Next

Comments 78601 to 78650:

78601. damorbel at 20:39 PM on 25 July 2011
       2nd law of thermodynamics contradicts greenhouse theory
       Re #1103 Tom Curtis, you give a link - http://web.mit.edu/16.unified/www/SPRING/propulsion/notes/node119.html This link is about heat tranfer in solids with various shapes - hollow shells, cylinders etc. under the general title "16.5 Steady Quasi-One-Dimensional Heat Flow" The explanation seems quite good to me but the title, as so ften is the case, is not really correct. What the author is describing is diffusion. Later in the article (perhaps an editor chose the title) he writes:- "The heat transfer rate per unit length is given by...." and give a formula that I can't copy here. The article is rather strange because further down it has :- "The steady-flow energy equation (no fluid flow, no work) tells us that....." Yet further it has:- "The heat transfer rate per unit length is given by... " with another formula that doesn't copy All very confusing and not really helpful for understanding the fundamental physics. You can check what Wikipedia has on this here :- Derivation in one dimension In your link the equation (16..25) corresponds to the last one in the 'one dimensional section' of the Wiki article where it adds helpfully :- "which is the heat equation. The coefficient k/(cpρ) is called thermal diffusivity and is often denoted α." You will also notice that the article refers to these equations as 'Fourier's law'.
78602. Tom Curtis at 20:16 PM on 25 July 2011
       2nd law of thermodynamics contradicts greenhouse theory
       Damorbel, it turns out that your history of science is almost as bad as your science:

       By 1800, alternatives to the caloric hypothesis appeared and, in 1811, Joseph Fourier (1768-1830) published a mathematical theory of heat conduction that was entirely independent of the caloric hypothesis. Fourier's first step was to avoid speculation about "caloric." In this way, Fourier set the study of the theory of heat in the tradition of rational mechanics, basing it on differential equations that characterized the transmission of heat, equations that were independent of all physical hypotheses. In contrast to Poisson (who was, as mentioned above, a devoted Laplacian, committed to physical mechanics and to the existence of caloric), Fourier focused on heat flow, using differential equations to express how much heat diffused from a substance over time. The heat transmitted between two molecules was proportional to the difference in their temperature and a function of the distance between them, which of course varied with the nature of the intervening substance. Though formally (that is, mathematically) equivalent to Poisson's model, Fourier did not rely upon any speculation about the nature of heat. For Fourier, what was important was not what heat was, but what it did, in a given experimental setting."

       (source, emphasis added) So, Fourier made not commitment to calorific theory, for which there where alternatives at his time. What is more he directly declared his agnosticism on the issue:

       "Of the nature of heat uncertain hypotheses only could be formed, but the knowledge of the mathematical laws to which its effects are subject is independent of all hypothesis; it requires only an attentive examination of the chief facts which common observations have indicated, and which have been confirmed by exact experiments."

       (Joseph Fourier, Theory of Heat, p 26) Further, if the the independence of mathematical theory of heat flow was not independent of calorific theory, then calorific theory would be established as true, for certainly his mathematical treatment of heat flow is. As it stands, his theory is independent of calorific theory (contrary to your claims) but consistent with the metaphor of heat flow (again contrary to your claims) as is established by his use of that very metaphor. What is more, as is established by the actual practice at MIT, that metaphor is alive and well in physics today, and causes no confusion. Except, perhaps to small minded pedants.
78603. Tom Curtis at 19:36 PM on 25 July 2011
       Milankovitch Cycles
       Glenn Tamblyn @31, just speaking of the top of my head but, wouldn't the first response by by early snow melts in as yet unglaciated land areas. Because of the preponderance of land in the Northern Hemisphere, this would lead to greater sensitivity in the NH which is necessary to explain the asymmetric response between the hemispheres. If sea ice is the first element to respond to the Milankovitch cycle, that would suggest a significantly stronger SH response than NH. Further, my understanding is that the sparse land masses north of 60 degrees South in the SH prevent the build up of continental ice sheets, and hence prevent the lapse into an ice age. On that basis I would suggest that if the SH had a similar land distribution to the NH, that would lock the Earth into permanent glacial conditions rather than prevent glacial conditions from forming.
78604. Glenn Tamblyn at 19:23 PM on 25 July 2011
       Milankovitch Cycles
       Let me suggest several contributing factors to what happens over a glacial/interglacial cycle. Starting at the bottom of a glacial. Milankovitch triggers some warming. Sea ice responds faster than land ice so more warming. Oceans respond with CO2 outgassing. Slowly the land starts to respond which is primarily northern hemisphere. Moderate ice sheet retreat starts to produce more melting permafrost, more methane. Later in the cycle, land ice sheets start to respond - it takes a fair old while to remove ice sheets kilometers thick. So albedo change and more warming, but only late in the cycle. Also, as ice sheets retreat polewards, geography and trigonometry come into play - more change early, declining change later. As ice sheets retreat they leave bare rock. Over 100's and 1000's of years this bare rock is slowly converted to soil and biomass. A carbon store. Then Milankovitch starts to tip things the other way. A bit of cooling. First impact of cooling is to extend snow ranges towards the equator. A snowfall can have as much effect on albedo as a huge ice sheet, but it can happen much quicker. so albedo change can have a bigger impact earlier in the cooling phase. Cooling triggers CO2 uptake by the oceans. More cooling. However, all that new biomass on the colonised rock is still there. How long does it take to kill off those recent forests and return their CO2 to the oceans or the atmosphere. In the intervening period, will they hold CO2 levels up even as Milankovitch and Albedo are cooling things. This surely makes for a nice complicated cycle over 1 glacial period. And all of this is probably due to the assymetric configuration of the continents between morth & south. If the Earth's continents were arranged symetrically, we may not see ice ages. And past arrangements of the continents probably had a huge impact on the Earth's predisposition to Ice Age behaviour or not.
78605. alan_marshall at 18:57 PM on 25 July 2011
       OA not OK part 10: Is the ocean blowing bubbles?
       Thus the temperature change required to sufficiently change the Henry's Law coefficient is 140/200 × 16 = 11oC Doug, I am enjoying the series so forgive me for being picky. I read you as saying the quantity of outgassed CO₂ is an exponential function of temperature. As this function is by definition non-linear, are you justified in using linear interpolation to get 11oC? I suggest this value should be a little higher.
78606. Tom Curtis at 17:27 PM on 25 July 2011
       China, From the Inside Out
       Agnostic @87, I can clearly see the point you are making. I can also clearly see the fallacy involved. I think you come to the position from shoddy thinking rather than racism, but at its root your position comes down to the assumption that one US citizen is worth four Chinese citizens, is worth twenty Indian citizens. It is further premised on the idea that the US (and other Western nations) because they have profited greatly from the exploitation of fossil fuels, should be absolved of any responsibility for any harm that exploitation will do; and indeed that they have only one quarter of the responsibility for future action to prevent harm from it than is born by any Chinese citizen. Such an idea may fly well on fox news, but it won't fly in China or India. Nor to China or India have self interest gulling them into accepting transparent nonsense. So as long as the West sticks to that premise as a basis of negotiation, for that long they guarantee that China and India will not sign up to any substantive cuts in emissions on any time table.
78607. ianash at 16:16 PM on 25 July 2011
       Rising Oceans - Too Late to Turn the Tide?
       so pirate, you've been given at least three separate sources that show that you are incorrect. Will you have the good grace to admit that your statements were wrong?
78608. Riduna at 15:34 PM on 25 July 2011
       China, From the Inside Out
       Tom Curtis @86 Again, the right to energy is conflated with an assumed necessity to emit CO2-e. Energy can and will be (already is) produced from clean sources and I certainly accept that the R&D into best achieving this outcome is largely the responsibility of the developed world. Likewise it is responsible for making that technology affordable for poor nations. Lovely column chart though of course it does rather ignore, at least not disclose the difference between the differing numbers of per-capita’s in each country and so avoids disclosing any national emission totals or the extent to which they contribute to global warming. Shorry you can not or do not want to see the point I making.
78609. Tom Curtis at 15:00 PM on 25 July 2011
       China, From the Inside Out
       Agnostic @85, in that case at what rate do you suggest the west subsidize China to reduce its emissions then? Absent such a subsidy, you are asking the poor to pay for the emissions reductions and at a far higher utility cost than the rich are prepared to pay.
78610. Ger at 14:34 PM on 25 July 2011
       Rising Oceans - Too Late to Turn the Tide?
       What will be the effect of the rising pressure of the sea on the lower agricultural grounds? Will the salt water level rise to an extend that it is not usable any-more? Seems to me especially a problem from Zeeland and Noord-Holland provinces in the Netherlands AND for large delta areas. It can be that rising water levels in rivers will counter the effect. For rivers already locked in by dykes that effect will be less.
78611. Doug Mackie at 13:44 PM on 25 July 2011
       OA not OK part 8: 170 to 1
       Thanks Sarah, though overall weathering actually produces mainly bicarbonate HCO₃^- (Eq. 4) We discuss alkalinity in post 12. Seawater alkalinity is a more complex expression than that for freshwater and also includes species like B(OH)₄^-, SiO(OH)₃^-, and HF.
78612. Doug Mackie at 13:34 PM on 25 July 2011
       OA not OK part 10: Is the ocean blowing bubbles?
       Byron, your question has some subtleties that mean it is hard to give a soundbite answer so bear with me and I will answer what I think you mean. I think you mean: "Under the current regime of increasing retention of heat energy and of increasing atmospheric CO₂, then how much would the oceans have to warm for the oceans to become a net source of CO₂?" In a closed system in a laboratory water reaches an equilibrium with the gases above it. That equilibrium is described by a Henry's law coefficient. So the first point to clarify is that the atmospheric doubling per 16^oC warming we noted refers to a system with constant atmospheric CO₂ and is useful to describe what happens when water moves between the poles and the tropics. The second point to note is that unlike a closed system in a test tube the ocean is an open and dynamic system. In most areas the ocean is not in equilibrium with the atmosphere. See this plot of Hawaii ocean data (HOTS) and Mauna Loa atmospheric data. The disequilibrium has several causes, including biological uptake and export to deep water. Some areas of the ocean are a source of CO₂, though overall the ocean is a strong sink. With biological processes taking up carbon then equilibrium is not reached and so long as the atmospheric pCO₂ is greater than that of the surface ocean then (for realistic warming)the oceans will take up CO₂. (Though the rate of uptake may change).
78613. Sarah at 13:25 PM on 25 July 2011
       OA not OK part 8: 170 to 1
       Jeff, You are correct that a mixture of only CO2 and water won't make pH 8 (I did not mean to suggest that). Pure water in equilibrium with air is about pH 5.7. Weathering has added CaCO₃ to the oceans over millions of years, which dissolves to the base CO₃^2-. Alkalinity (AT) is a measure of how much "excess" base is in the system, for example, how much CO₃^2- came in with Ca²⁺ instead of with H⁺ as the counter ion (to balance the charges, you can't add negative charge without adding + charges too). The charge balance in the system provides another constraining equation. The sum of charges of all the species present must add up to zero. The pH is determined by how much of the charge ends up being H₃O⁺ after all the equilibrium equations are satisfied.
78614. John Hartz at 13:22 PM on 25 July 2011
       Gripping video of Arctic sea ice melting away before your eyes
       What the video doesn't show is described in Melting Arctic ice releasing banned toxins, warn scientists an article posted (July 24) on Guardian.co.uk. The negative consequences that melting Artctic sea ice is having, and will continue to have, on the ecology of the Earth are many, and they are severe.
78615. scaddenp at 13:01 PM on 25 July 2011
       Rising Oceans - Too Late to Turn the Tide?
       There was a public meeting here about sealevel rise and it's threat to the city (which has some immediate issues) with contributions from surveyors, engineers, town planners etc. One very good point that an engineer made was that scope and affordability of engineering solutions was inversely proportional to total expected sea level rise. If the rise is around 1m, then engineering is possible and effective. If it is 2-3m then retreat is only realistic option.
78616. barry1487 at 12:52 PM on 25 July 2011
       Milankovitch Cycles
       Yes, I thought the equivalent warming of both hemispheres over Milankovitch cycles was strong evidence, firmly corroborated by the ice core (and other) records of both hemispheres, that GHGs play a significant role in global temperature changes. The only other mechanisms I can think of for this effect are atmospheric teleconnections and lateral heat transport via ocean currents, but even so, hemispheric temperatures would be significantly different for periods where one hemisphere is receiving more insolation than another - except for GHGs.
78617. Paul Magnus at 12:51 PM on 25 July 2011
       Rising Oceans - Too Late to Turn the Tide?
       #20 Bad, Yes, but peer review information is now coming out indicating that, especially if we dont reduce our rate of emission, but even if we do, that we might (could) get 5-6ft by around 2100. And then it will keep going up and up.... They take about 6ºC giving 4ms, but we can see in this article (& from Hansen) that a 1ºC rise from now will result in a 8m rise at some point. What this article shows also is that it is not stopping there, but will continue on to around 20ft+ even if we do stop our emissions as there is at least .7ºC in the pipeline and probably more. We also have to get back to around 350ppm and below before we see equilibrium (Hansen). It really does not make sense for the Netherlands to spend billions and billons to defend when they will have to retreat. That money could be better spent. This reality has to enter the debate now. Nothing is certain, but this is looking more and more certain with each year! And the current data should cause pause for re-review of strategy I would guess considering the cost.
78618. villabolo at 12:33 PM on 25 July 2011
       SkS Weekly Digest #8
       
78619. Riduna at 12:19 PM on 25 July 2011
       China, From the Inside Out
       Tom Curtis @84 I would have thought it obvious from my remarks made it clear that the last thing I expect is for any country to be excused reducing their emissions. Your suggestion that I expect poorer nations to bear the burden of reducing their emissions is as fallacious as suggesting that a 50% increase in China’s emissions is conducive to limiting global warming to less than 2C.
78620. Doug Mackie at 11:19 AM on 25 July 2011
       OA not OK part 10: Is the ocean blowing bubbles?
       Fixed.
78621. Bern at 10:51 AM on 25 July 2011
       OA not OK part 10: Is the ocean blowing bubbles?
       "However, this amount of released fossil fuel CO2 is less than the amount of extra CO2 that is currently in the atmosphere." Should that be greater than?
78622. Bern at 10:41 AM on 25 July 2011
       OA not OK part 9: Henry the 8th I was (*)
       Doug, no, my opinions on climate change are almost diametrically opposed to Ken's. :-)
78623. pauls at 10:34 AM on 25 July 2011
       Monckton Myth #16: Bizarro World Sea Level
       There appears to be no end to the hilarity that can be drawn from Morner's recent work. This quote from his 2004 paper Estimating future sea level changes from past records is brilliant: 'IPCC launched their hypothesis of a disastrous flooding of coastal low-lands and low islands (like the Maldives) in the next century (e.g. Hoffman et al., 1983).' That's right, his example of the IPCC (founded in 1988) hypothesis of disastrous flooding is a paper from 1983. The 'modelled vs observed' graph is actually appears to be a comparison between Church & White 2006 and a multi-source record described in Morner 2004. The Church & White data can reasonably be termed 'model data' since they use a model to infer global sea level change from coastal tide gauge data back to 1870. However, in no way could this be termed a 'prediction', as suggested in the legend. How Morner arrives at the 'observations' plot is interesting. The data from 1840 to 1960 is quite reasonably a mean of tide gauges, giving a fairly standard average SLR of ~1.2mm/yr over the whole period. Then things get weird. He states 'During the 1970s and 1980s, our data are not really clear enough for a proper evaluation of any general trend in sea level.' How this could be isn't explained but, undeterred, he moves right on to the satellite era (~1990 to present) which he determines shows no trend, contradicting everyone else in the world with no explanation. Note on the graph that there is also no trend from about 1960 to 1990. How was this determined given the documented sudden loss of data during the 70s and 80s? Well, his only reference that includes this period is to calculated contributions to sea level change over 1910-1990 from various sources, as documented in IPCC TAR 2001. He cites the figure 0.9mm/yr though it's unclear from where because the central value given by the IPCC is actually 0.7mm/yr (Link). So the curve after 1960 is an attempt at reconciling the long-term 1.2mm/yr trend with the IPCC 0.9mm/yr (0.7mm/yr) figure to 1990. And I think he massively overdoes the 'correction' too. No matter though, the great thing about this is that the IPCC figure is largely derived from modelling studies. So the point at which the 'models' and 'observations' diverge is the point at which the 'observations' become 'models'.
78624. Dcrickett at 10:34 AM on 25 July 2011
       OA not OK part 10: Is the ocean blowing bubbles?
       Mr Smith: Excellent question; thanks for asking it. I too am curious.
78625. Tom Curtis at 10:30 AM on 25 July 2011
       China, From the Inside Out
       Agnostic @83, your argument is most commonly coupled with the argument that because China is not reducing its emissions, then Australia and the US ought not to reduce their emissions because doing so would merely cripple their economy without effecting our long term prospects of combating global warming. At the very minimum the chart @82 shows this is false. In fact, that argument pair is always just a rhetorical device to block effective action on climate change with out directly arguing against action on climate change. It is difficult to see how your position differs. Specifically, there is no hope in the world that China, or India will sign up to emissions reductions at a rate comparable to those of the west in terms of absolute emissions per nation. Nor should they. There will undoubtedly be a short term cost in moving to a zero (or very low) emission economy. The demand for equal per nation reduction in emissions is therefore a demand that the poorest nations accept a greater cost so that the wealthy nations that have caused the problem can minimize their costs in the transition. Quite apart from any consideration of equity, the fact is the cost for western nations will be easily paid out of discretionary income from the household budget. In Third World nations the cost will be in terms of the elimination of health services, and of educational opportunities, and in many cases the ready availability of food. For China the cost of an equal per nation reduction will be eliminating the growth of the middle class. Economists have a useful term for analyzing costs. It is "utility". In rough terms, the utility cost is the cost in actual happiness or opportunity. In those terms, because fighting global warming means, for the West, trimming luxuries, and for the third world, trimming necessities, the utility cost in the third world is far higher for an equal reduction in emissions. Therefore your policy prescription is that the third world bear a greater cost in necessities so that we can have a reduced cost in luxuries for any given outcome. The proper response to that to anyone, including you, is that if you think the situation so lacking in urgency that you are prepared to haggle amount how many luxuries you will give up, then it is insufficiently grave for the third world to give up a single necessity.
78626. John Hartz at 10:17 AM on 25 July 2011
       Rising Oceans - Too Late to Turn the Tide?
       @ Paul Magnus #11: Exploring high-end climate change scenarios for flood protection of the Netherlands Ministerie van Verkeer en Waterstaat (VenW) P. Vellinga, C. Katsman, A. Sterl, J. Beersma, W. Hazeleger ...(etc.), Koninklijk Nederlands Meteorologisch Instituut, 2009 This international scientific assessment has been carried out at the request of the Dutch Delta Committee. The Committee requested that the assessment explore the high-end climate change scenarios for flood protection of the Netherlands. It is a state-of–the art scientific assessment of the upper bound values and longer term projections (for sea level rise up to 2200) of climate induced sea level rise, changing storm surge conditions and peak discharge of river Rhine. It comprises a review of recent studies, model projections and expert opinions of more than 20 leading climate scientists from different countries around the North Sea, Australia and the USA. Although building on the previous IPCC AR4 (2007) and KNMI (2006) assessments, this report deliberately explores low probability/high impact scenarios, which will pose significant threats to the safety of people and infrastructure and capital invested below sea level. According to its high-end estimates global mean sea level may rise in the range of 0.55 - 1.10 m in 2100 and 1.5 - 3.5 m in 2200, when higher temperature rise scenarios (up to 6 °C by 2100) and increased ice discharge from Antarctica are considered. This would correspond with local sea levels along the coast of the Netherlands of up to maximally 1.20 m in 2100 and 4 m in 2200. An increase in peak discharge of river Rhine of 3 to 19% for 2050 and 6 to 38% for 2100 is foreseen. The storm regime along the Dutch North Sea coast in terms of maximum surge level will probably not change significantly in this extreme climate change frame. To access the PDF of the full report, click here.
78627. muoncounter at 10:07 AM on 25 July 2011
       Rising Oceans - Too Late to Turn the Tide?
       Paul Magnus#11: "as these data come out surely they will have to reconsider and start thinking about retreat" Check it for yourself at this sea level rise mapping site. Even at +2 meters, its not pretty for Rotterdam, Amsterdam, Gronigen, etc.
78628. Riduna at 09:38 AM on 25 July 2011
       China, From the Inside Out
       Tom Curtis @ 78 The points I make is that only nation-states can (and should) exercise control over their CO2-e emissions. Those emissions are and should be measured in national total tonnage and it ought to be recognised as the basis for international agreements. Global warming occurs because of total CO2-e emissions, the aggregate of total national emissions, irrespective of variance in per-capita emissions among nations. I do not subscribe to the view that, by virtue of having a large population, it is acceptable for China to increase its emissions by ~50%, from its present 7.7 gigatonnes per annum to >11 gigatonnes per annum, or that this is consistent with limiting temperature increase to <2°C by 2100. And there is certainly no evidence that China has either the intention or capacity of reducing its emissions to zero by 2030. Such proposals are unrealistic and dangerous for our future. It is wrong to equate the right to higher per-capita energy entitlement with the right to increase CO2-e emissions. No one disputes that China or India have a right to improve the standard of living of their vast populations by increasing availability of per-capita energy. What is disputed is that this justifies increasing CO2-e pollution or that such an increase is unavoidable and necessary. Global CO2 emissions are approaching 400ppm compared with a “safe” target of 350ppm. The world is heading for a catastrophic 4-5°C increase by 2100, sea level rise of at least 1m, possibly up to 5m and a climate so extreme that our ability to survive will be sorely challenged – yet it is seriously suggested by commentators that major increase in CO2 pollution is justified. My response is and remains NO!
78629. Robert Murphy at 09:33 AM on 25 July 2011
       Rising Oceans - Too Late to Turn the Tide?
       Climate4All@15, A one paragraph prediction in Popular Science (repeated in Popular Mechanics) by someone who was mostly an anthropologist is supposed to be well known to people discussing climate science? Where is there any indication this prediction was ever reported beyond this cite? And your quote is incomplete. Here is the full one (which your link actually provided in full): "Sea level the whole world over is five inches higher than it was in 1895, says Dr. George F Carter, Johns Hopkins University geographer. Because this is the tail end of a glacial period, polar ice is melting and filling up the oceans. Future harbor works should be planned for an expected sea level rise of 24 inches within the next century, Dr. Carter advises" And it should be noted he's just wrong; sea level was not rising because "this is the tail end of a glacial period". We have been in the middle of an interglacial for thousands of years. If he meant the "Little Ice Age", he would still have to provide a physical reason for why sea level started rising; it didn't start rising because it had been colder before. Sea level had been rising because of a combination of increased solar irradiance and rising GHG's warmed the Earth. Since the middle of the 20th century, the warming has been primarily from GHG's. The musings of someone without a lot of background in sea level rise speaking at a time when that science was in its infancy, and quoted in 2 magazines for laymen has no relevance to the science as it is now. Why bring him up? His prediction had no influence.
78630. Rob Painting at 09:24 AM on 25 July 2011
       Rising Oceans - Too Late to Turn the Tide?
       Pirate @ 12 - the 'eyecrometer' is not a precise tool, hence the use of statistical analysis: Sea level rise is accelerating. See Church & White (2011) and this SkS thread From the study: "There is considerable variability in the rate of rise during the twentieth century but there has been a statistically significant acceleration since 1880 and 1900 of 0.009 ± 0.003 mm year and 0.009 ± 0.004 mm year-2 , respectively. Since the start of the altimeter record in 1993, global average sea level rose at a rate near the upper end of the sea level projections of the Intergovernmental Panel on Climate Change’s Third and Fourth Assessment Reports" And to illustrate the point about IPCC sea level projections and actual observations (your last graphic isn't clear enough): Actual sea level rise is tracking the upper bound of projections. Pirate - "So, whether we look at 18 years, 120 years, or 8,000 years we are seeing a linear response." Let's check the last 2000 years or so. Discussed in: A sea level hockey stick No linear sea level response there either.
78631. John Hartz at 09:09 AM on 25 July 2011
       Rising Oceans - Too Late to Turn the Tide?
       Let us also not loose sight of the fact that sea level rise is not distrubuted uniformly throughout the Erath's ocean systems. To learn more about this topic, go to: SkS Thinning on top and bulging at the waist: symptoms of an ailing planet
78632. scaddenp at 09:01 AM on 25 July 2011
       Human CO2 is a tiny % of CO2 emissions
       Ken, please see the thread Water vapour is the most important greenhouse gas.
78633. scaddenp at 08:53 AM on 25 July 2011
       Sea level rise is exaggerated
       Eric the Red, you may be interested in the analysis of this paper How not to analyze tide gauge data. While this analysis isnt published (though I am encouraging the author to do so) it is basically the same cherry pick as H&D. See here for published criticism of this kind of cherry pick.
78634. Climate4All at 08:46 AM on 25 July 2011
       Rising Oceans - Too Late to Turn the Tide?
       @Composer99 A citation wouldn't be necessary if those that said they were knowledgeable of facts, were actually knowledgeable of the facts. Dr. George F. Carter was quoted as saying, “Sea level the whole world over is five inches higher. Because this is the tail end of a glacial period, polar ice is melting and filling up the oceans. Future harbor works should be planned for an expected sea level rise of 24 inches within the next century.” This quote and another like can be found in Popular Mechanics Mar'53 and Popular Science Feb.'53. George F. Carter taught at John Hopkins University as acting chair of the Geography Dept., and at Texas A&M as Distinguished Professor of Geography. Before he taught at John Hopkins, he served as an analyst for the Office of Strategic Services(better known as the C.I.A.), during WWII. Two papers worth reviewing his extensive work are: EARLY MAN AT SAN DIEGO: A GEOMORPHIC·ARCHAEOLOGICAL VIEW & MAN, TIME, & CHANGE IN THE FAR SOUTHWEST. Or, if you like, there are many reviews of his works on geography/anthropology. If he was alive today, he would probably tell you that he was a climatologist as well. In his work, he used sediment readings from many parts of the world and had concluded that there have been at least 2 interglacial periods before this current one and that seas had risen 100s of feet before, and quite likely, will do so again. Dr. Carter had even mentioned that without some sort of relapse(cooling), that the seas could repeat the process again, possibly in our lifetime or our children's lifetime. Dr. Carter passed away in 2004. He will be missed.
       Response:

       [DB] "A citation wouldn't be necessary if those that said they were knowledgeable of facts, were actually knowledgeable of the facts."

       A citation was politely asked for.  Perhaps emulating civil behavior by responding politely sans attitude would allow for better engagement and dialogue.

       Or you can continue down this path and we can see what happens.

       Your call.

78635. Byron Smith at 08:44 AM on 25 July 2011
       OA not OK part 10: Is the ocean blowing bubbles?
       Thanks - excellent summary of an important point that is much misunderstood, but has to be one of the most secure pieces of the big climate puzzle (not saying that other pieces do not have good evidence, but this one is, in my impression, totally in the bag and can be a good test of whether people are really out to lunch if they continuing questioning it). This post actually gave me a small piece of reassurance in saying that for the oceans to become a major net carbon source, they would have to warm a loooong way (especially since oceans warm much slower than atmosphere). One of the concerns about warming oceans is that their function as a carbon sink will decline, leaving more of our CO2 in the atmosphere. This is one of many potential positive feedbacks that magnify a small change into a bigger change. But even if the ocean declines as a carbon sink (which is bad), it seems unlikely to become a carbon source anytime soon (which would be really, really bad). And so here is my quick question on this topic: how much would the oceans have to warm to make the switch from sink to source?
78636. scaddenp at 08:43 AM on 25 July 2011
       Milankovitch Cycles
       Camburn, did you read #17? The change in albedo (largely) in NH sets up GHG feedbacks which are global not hemispheric. No puzzle at all.
78637. muoncounter at 08:36 AM on 25 July 2011
       Rising Oceans - Too Late to Turn the Tide?
       pirate#12: "So, whether we look at 18 years, 120 years, or 8,000 years we are seeing a linear response." See the prior thread, Has sea level rise accelerated since 1880? Whether sea level showed 20th-century acceleration or not, it’s the century coming up which is of concern. And during this century, we expect acceleration of sea level rise because of physics. Not only will there likely be nonlinear response to thermal expansion of the oceans, when the ice sheets become major contributors to sea level rise, they will dominate the equation. Their impact could be tremendous, it could be sudden, and it could be horrible.
78638. Tom Curtis at 08:28 AM on 25 July 2011
       Gripping video of Arctic sea ice melting away before your eyes
       eldorado2768, a time and date stamp for each frame is in the top left corner. The data also shows the location (latitude and longitude and pitch), but not the internal temperature which I know to be recorded :(. Anyway, the time interval is from early March 22nd to July 22nd, 2011.
78639. Tom Curtis at 08:23 AM on 25 July 2011
       Rising Oceans - Too Late to Turn the Tide?
       apirate @12, the IPCC projections are not linear, and explicitly exclude melt water from glaciers because they are not sufficiently predictable. Those glaciers will melt, however, or at least a significant amount of the Greenland Ice Sheet and the West Antarctic Ice Sheet will melt although it will probably take centuries to do so. Based on your second graph (from wikipedia, I believe) the sea level rose 115 meters in the 8 thousand years from 16k before present to 8 k before present. That represents a rate of rise of 144 mm/decade, and is a reasonable projection for the rate of rise by the end of this century. That would yield a sea level rise in the order of 650 mm by 2100, and double that for the following centuries until the 6 to 8.5 meter rise above current levels is achieved, assuming we restrict GHG emissions sufficiently to restrict global temperature increases to 2 degrees C. Contrary to many commentators here, I believe that those rates are well withing the economic means for adaption; but I also think sea level rise will cause the least economic hardship globally of the various risks from global warming.
78640. muoncounter at 08:20 AM on 25 July 2011
       The Medieval Warm(ish) Period In Pictures
       Camburn#56: "I have not seen any rebuttals to the Sargasso Sea temperature proxies." Perhaps not. However, here is an excellent rebuttal to the numerous misrepresentations of Keigwin's Sargasso Sea data that continue to rebound throughout deniersville. Keigwin’s Fig. 4B (K4B) shows a 50-year-averaged time series along with four decades of SST measurements from Station S near Bermuda, demonstrating that the Sargasso Sea is now at its warmest in more than 400 years, and well above the most recent box-core temperature. Taken together, Station S and paleo-temperatures suggest there was an acceleration of warming in the 20th century, though this was not an explicit conclusion of the paper. Keigwin concluded that anthropogenic warming may be superposed on a natural warming trend. ... Keigwin’s Fig. 2 showed that δ18O has increased over the past 6000 years, so SSTs calculated from those data would have a long term decrease. Thus, it is inappropriate to compare present-day SST to a long term mean unless the trend is removed. -- emphasis added This analysis, Misrepresentation of Scientific Data by Hillary Olson at UT, is based on a 2010 GSA talk by Boslough and Keigwin. It features a point-by-point demonstration of the manner in which deniers cherry-pick from a legitimate study, modify, distort and misrepresent. It includes a discussion of how internet memes arise and gain traction despite being factually incomplete or incorrect. This particular 'Saragasso Sea was warmer way back when' meme is traced to the folks behind the Oregon Petition. For the benefit of any skeptical educators, Olson includes the relevant sections from the Texas Essential Knowledge and Skills (TEKS): The student uses critical thinking, scientific reasoning, and problem solving to make informed decisions within and outside the classroom. The student is expected to: (A) in all fields of science, analyze, evaluate, and critique scientific explanations by using empirical evidence, logical reasoning, and experimental and observational testing, including examining all sides of scientific evidence of those scientific explanations, so as to encourage critical thinking by the student; (B) communicate and apply scientific information extracted from various sources such as current events, news reports, published journal articles, and marketing materials; (D) evaluate the impact of research on scientific thought, society, and public policy; It is too bad those skills are in such short supply these days.
78641. eldorado2768 at 08:12 AM on 25 July 2011
       Gripping video of Arctic sea ice melting away before your eyes
       What timeframe do the spliced images cover? I think that would be helpful information.
78642. Tom Curtis at 08:04 AM on 25 July 2011
       China, From the Inside Out
       Byron Smith @80, the original for the graph comes from the WBGU report, "Solving the Climate Dilemma: The Budget Approach" (PDF). It is an excellent policy advisory document, and maintains neutrality between various policy options, including an historical responsibility approach, in which each nation has a per capita budget starting in 1990 (which has been already spent in the case of the US and Australia). I tend to ignore it as I do not think it would ever be accepted by the US. I do apologize for the condition of the original graph. I was posting away from home, and did not have access to my favourites bar. Here is a better version from SkS:
78643. Robert Murphy at 07:49 AM on 25 July 2011
       Human CO2 is a tiny % of CO2 emissions
       Ken at 123: "Why doesn't the GHG chart include Water Vapor..." Because it is an emissions chart. Our emissions have no direct effect on global water vapor levels; those levels are a direct function of global temps, and essentially nothing else. Water vapor is the only GHG that will precipitate out of the atmosphere at temps we experience. The other GHG's stay aloft a lot longer, in particular CO2. Water vapor really only acts as a feedback, not as a forcing. Our emissions of other GHG's are forcings.
78644. michael sweet at 07:48 AM on 25 July 2011
       Gripping video of Arctic sea ice melting away before your eyes
       The melting of the ice shelves on Ellesmere Island show that the Arctic ice is at the lowest level in at least the last 5,000 years. Since 2011 is currently lower than any other year measured, that means 2011 is the lowest for July 24 in at least 5,000 years. A Pirate: can you suggest a 5,000 year cycle that is peaking that would account for this collapse of the ice? If no such cycle can be proposed that indicates that the extraordinary melt this year is not due to natural cycles but instead to human influence. Please provide references to data to support your "natural cycles". It is not enough to suggest "natural cycles". You also have to provide data to suggest they exist. Without data you are just waving your hands.
78645. apiratelooksat50 at 07:39 AM on 25 July 2011
       Rising Oceans - Too Late to Turn the Tide?
       Muoncounter @ 3 If we go back 130 years we see the basically the same trendline. Going back 24K years we see a sharp rise following the meltwater pulse following the last glacial maximum. That sharp rise leveled out about 8K years ago to what we are experiencing now. And, from IPCC 3 we get their sea level projections. So, whether we look at 18 years, 120 years, or 8,000 years we are seeing a linear response.
78646. Ken at 07:34 AM on 25 July 2011
       Human CO2 is a tiny % of CO2 emissions
       Why doesn't the GHG chart include Water Vapor, which is, I believe, the largest GHG? When Water Vapor is included as a GHG, it represents 95% of the GHGs. I thought it was well established that Water Vapor plays the largest role in keeping the Earth at a temperature that will support life. We do not seem to be considering all the variables here.
       Moderator Response: See "Water vapor is the most powerful greenhouse gas."
78647. HK at 07:26 AM on 25 July 2011
       Milankovitch Cycles
       Camburn, if you compare the CO2 levels at Mauna Loa and the South Pole, you will see that they follow each other quite closely, despite the fact that the levels are rising much faster now than at the end of the last ice age. When the SH responds to the change in GHG’s, this response will cause a positive albedo feedback just as in the north, although not as strong. And BTW, one of the Milankovitch cycles, the obliquity or axial tilt, will affect both hemispheres in the same way as both poles get more insolation and the tropics get less.
78648. Paul Magnus at 07:25 AM on 25 July 2011
       Rising Oceans - Too Late to Turn the Tide?
       I bet no body really believes this, otherwise we would all be clamoring to address it! I wonder how Holland is reacting to these latest findings on the sensitivity of the ice to temp rise? They have opted for defense, but as these data come out surely they will have to reconsider and start thinking about retreat as the main strategy. Where are they all going to go?
78649. Composer99 at 07:25 AM on 25 July 2011
       Rising Oceans - Too Late to Turn the Tide?
       Climate4All: {citation needed}
78650. Paul Magnus at 07:20 AM on 25 July 2011
       Rising Oceans - Too Late to Turn the Tide?
       "We expect something quite different for the future because we're not changing things seasonally, we're warming the globe in all seasons," McKay said." Surely the main forcing once warming got underway was GHGs which reenforced the seasonal warming and at some point takes over. Would be interesting to find this point where the ghg feedback takes over from orbital forcing....

Prev  1565  1566  1567  1568  1569  1570  1571  1572  1573  1574  1575  1576  1577  1578  1579  1580  Next