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Comments 58501 to 58550:

58501. Bob Lacatena at 08:22 AM on 20 May 2012
       CO2 lags temperature
       Dougal, I'm heading out, but no, it is not the closeness of the orbit. There are multiple factors, including axial tilt, precession, shape of the orbit (ellipse versus circular), and others. Distance changes very little. I'll explain more later.
58502. Dougal at 08:06 AM on 20 May 2012
       CO2 lags temperature
       @Sphaerica 358: Sorry, it was not the relative rate of warming to cooling I was raising, but the fairly constant (albeit different) rate in both. Unusual in a cyclic system where rates are less at the peaks and maximum at the mid points. But since you raise it, why is it easier to melt than freeze - is it because melt water runs off exposing more of the cold ice sheet and maintaining a larger temperature incline at the sheet compared to when it is growing as water freezes it heats the local air reducing the temperature incline and so rate of growth? Possibly also because it can welt whenerver the temperature is high enough, while to grow it needs an equivalent cold temperature and water.
58503. Dougal at 07:59 AM on 20 May 2012
       CO2 lags temperature
       @Sphaerica 355: That seems a bit disengenuous - it is the closeness of the orbit that is causing the longer NH summer and shorter NH winter which increases the icemelt and reduces the ice growth which leads to temperature change which amplifies the ice sheet change. I believe from what you said that the amount of cooling/heating is related to the size of the ice sheets - larger ice sheets, more reflection. Similarly the length of NH summer/winter is related to the closeness of the orbit adjusted on a shorter period cycle by tilt and wobble - closer orbit, longer summer, reduced ice sheets, more cooling. Lastly the temperature also changes the CO2 level (in the past) and warmer oceans release more C)2 which increases the warming and reduces the ice sheets, etc. So these three factors combine cause increasing warming the warmer the planet gets. So at the end of a glacial period we have minimum CO2, and maximum ice sheets, while the orbit is getting closer at a cyclic rate - why isn't there balance and a slow shift to warming? Is there something that causes the ice sheets to start melting quickly despite only small change in NH winter/summer, extensive ice sheets and sustained high CO2? That is what I can't reconcile. Do any of the linked reports have graphs which include the Milankovitch cycle, or anywhere that has the Milankovitch cycle data which I can then combine with that from Petit (2000) to generate my own analysis? In fact I think that is what I will need to do, to lok closely at the rate of change which appears to spike massively at the 'tipping points'.
       Moderator Response: TC:Suggesting that another poster is disingenuous is sailing close to the wind on the comments policy, especially with regards to the clauses about no ad hominens, and the requirement to not be inflammatory. If a moderator deems you to have violated the comments policy, they may warn you, snip the offending text, or simply delete the entire comment. The later is by far the easiest procedure, so by violating the comments policy you make your post a hostage to fortune. A word to the wise... In this case I have given you the benefit of the doubt and assumed you are not suggesting that Sphaerica is dishonest (which would violate the comments policy), but only that he has not discussed all the relevant facts. If you continue to counter corrections to your factual errors with similar suggestions, I will not continue giving you the benefit of the doubt.
58504. Tom Curtis at 07:58 AM on 20 May 2012
       David Evans: All at Sea about Ocean Warming and Sea Level Rise
       dana1981 @13, to be more specific, a theory is "not even wrong" when it is so confused a hypothesis as to be meaningless. Rationalwiki gives the example:

       "2 + zebra ÷ glockenspiel = homeopathy works"

       and goes on to say:

       "The strict definition of "not even wrong" applies when the premises of an argument are known to be false (based on observational evidence or similar), or when they are used to describe theories which cannot possibly be falsifiable or provide meaningful predictions. For example, any physical theory based on the existence of the aether, and any biological idea based on evolution by Lamarckian inheritance would be classed as not even wrong. In this case, it is a type of formal logical fallacy as using incorrect or non-applicable premises will always yield an incorrect answer. As the premises are wrong the conclusion is certainly incorrect, but the conclusion is at least correct based on said premises. The term "not even wrong" therefore describes this situation. For a clear but silly example, one can say that "this chair is made of hard, solid wood, therefore I can sit on it". This is perfectly true, except in the case where the chair is made of jelly. The conclusion is correct based on the premise, but the premise is clearly not applicable. Therefore we the conclusion is not even wrong."

       It is in the sense that the premises of Evan's arguments, eg, that the ocean heat content data before 2003 is worthless, are known to be false that his arguments are not Evan wrong. That sense is an extension of its original, and literal meaning in which claims are "not even wrong" if they are so vague, poorly constructed as to be literally incapable of falsification by any data.
58505. Dougal at 07:40 AM on 20 May 2012
       CO2 lags temperature
       @Sphaerica Thanks you for those. Sorry for the long post, but needed to try to explain the piece I was missing. I will address if I may also in parts. 357: So it relative to a nominal temp, thanks. Change (as I understand it) just didn't make sense (to me anyway).
58506. andylee at 06:41 AM on 20 May 2012
       David Evans: All at Sea about Ocean Warming and Sea Level Rise
       Dana, reference is at TED Talks @ 7:45 Also referenced in Peter Sinclair's excellent video @ 7:24
58507. littlerobbergirl at 06:37 AM on 20 May 2012
       David Evans: All at Sea about Ocean Warming and Sea Level Rise
       Another source of 'potholes' is big dams. Couple of those filled recently.
58508. littlerobbergirl at 06:19 AM on 20 May 2012
       Climate Change Consequences - Often Unexpected
       The sewers went in long before the sewage treatment plants - i guess basilget et al welcomed the odd storm surge to give the system a really good flush now and then - they were designed to take it hence the upside down egg shape. So we have a 70s work around bolted onto a victorian 'just move it away a bit' system, just as we do with flue gas abatement. We use a resource, drinking water, to move another rescource, humanure, then add another resource, rainwater, and let it spill out into our rivers where it is least wanted. London mixed sewage overflow events now happen dozens of times a year instead of a couple; partly because of higher water use, partly more high rainfall events but also stupid things like front gardens being paved over with impermeable hard surfaces. I swam in raw sewage as a child i thought those days were over sigh.
58509. dagold at 05:16 AM on 20 May 2012
       Who Are the Most Prominent Advocates of Global Warming?
       Well, being the motivated climate activist citizen...I actually had a billboard put up in Minneapolis, Minnesota last Tuesday with the text "Guess who believes in Climate Change?" in response to the Heartland Billboard. My billboard directs you to the website: www.itsphysics.org Please go take a look-the first page lists quotations of various scientific and military organizations advocating action on climate change. Then (culled from this site over the years!) page 2 explains the BASIC physics of climate change. I wanted to put up my billboard in Chicago this week on the Heartland billboard site,but the billboard company wanted $1000 for a day (Minneapolis only charged $300...oh well)
58510. GCNP58 at 04:04 AM on 20 May 2012
       Who Are the Most Prominent Advocates of Global Warming?
       @ralbin #3: word.
58511. dana1981 at 03:25 AM on 20 May 2012
       David Evans: All at Sea about Ocean Warming and Sea Level Rise
       John Hartz @11 - there's a phrase "that's not even wrong" for something incredibly fundamentally wrong. "Evan" is a little wordplay on "even" in that phrase. andylee @12 - do you have a link to the 400,000 Hiroshima bombs comment? 2 per second is correct, based on the increase in ocean heat content, though it has also accelerated in recent decades/years, so perhaps that's what Hansen referred to.
58512. Dikran Marsupial at 03:23 AM on 20 May 2012
       CO2 has a short residence time
       Martin A Indeed in my paper I use a linear model, but it is only a local approximation of the real system. Linearisations of this type are quite common in physics and are good for getting the basic message across, but as I said in the paper it isn't really up to making useful quantative predictions. I think the problem is that you have the outflow being proportional to the volume, however this does not give a reasonable local approximation and you need a linear function of the volume instead (i.e. outflow = k v(t) + C). I think your model is perhaps too simple. This is the principal difference between your model and the one in my paper, so I assume it is where the difference lies. I intitally used a proportional model (as Essenhigh did) but found that if you plot the proportional relationship with the observations it gives an extremely bad approximation, which is why I used linear regression to get a better approximation.
58513. muoncounter at 03:17 AM on 20 May 2012
       Who Are the Most Prominent Advocates of Global Warming?
       Nitpick: No one really advocates global warming (except a few Barents sea crab fishermen frequently seen on the Discovery Channel). Perhaps it would be better to say 'The most prominent advocates of global warming science' Because the implicit message of Heartland is "Those who advocate science are ..."
58514. R. Gates at 03:04 AM on 20 May 2012
       Who Are the Most Prominent Advocates of Global Warming?
       We can only hope that Heartland's "Murders, Tyrants, and Madmen" statement is brought to the attention of even more of Heartland's sponsors and that even more will flee this organization that seems to have increasing difficulties managing its public messaging. How anyone will stay connected with this organization on any level is beyond me.
58515. andylee at 03:02 AM on 20 May 2012
       David Evans: All at Sea about Ocean Warming and Sea Level Rise
       According to Jim Hansen the energy imbalance is equivalent to 400,000 Hiroshima bombs per day - this is nearly 5 bombs per second, not 2 as stated above.
58516. ralbin at 02:55 AM on 20 May 2012
       Who Are the Most Prominent Advocates of Global Warming?
       This is, of course, excellent. But this is the same Mrs. Thatcher who stated "there is no such thing as society" and whose strident advocacy of neoliberalism played a significant role in undermining the legitimacy of dealing with environmental problems. This makes her recognition of global warming more salient but it shouldn't obscure her significant culpability for the difficulties experienced in developing sensible policy responses to global warming.
58517. Alexandre at 02:24 AM on 20 May 2012
       Who Are the Most Prominent Advocates of Global Warming?
       Why don't we have politicians like that nowadays? Maybe the deniers were indeed successful in manufacturing the controversy in the meantime. It became a touchy subject now.
58518. Daniel Bailey at 01:26 AM on 20 May 2012
       CO2 lags temperature
       

       "And with all of that said, the next orbital configuration to really get us into a true glacial state isn't supposed to be for another 10,000 to 20,000 years"

       Earlier, Tyrrell et al 2007 examined this, concluding that we have already skipped the next glacial epoch. Furthermore, Tyrrell concludes that if we continue our present fossil fuel consumption, we will skip the next 5 glacial epochs. With that said, per Tzedakis et al 2012, “glacial inception would require CO2 concentrations below preindustrial levels of 280 ppmv” (for reference, we are at about 396 right now…and climbing). With the millennial atmospheric lifetime of CO2, no glacial epochs will be occurring the next million years…
58519. otter17 at 01:09 AM on 20 May 2012
       Hockey stick is broken
       It seems that the link to the reconstruction data is broken (third link in the 'Further Reading' section). Current Link (broken): http://www.ncdc.noaa.gov/paleo/pubs/ Suggested Link: http://www.ncdc.noaa.gov/paleo/data.html
58520. Bob Lacatena at 01:02 AM on 20 May 2012
       CO2 lags temperature
       Dougal, Just to state it a little more directly (as to why the rise is fast, but the decline is slow)... it's a lot easier to melt the ice sheets and thereby increase CO2 and heat the planet, than it is to reduce the CO2, and thereby cool the planet and create new ice sheets. The two processes are not exact, diametric opposites. Hence the difference.
58521. dorlomin at 01:01 AM on 20 May 2012
       Who Are the Most Prominent Advocates of Global Warming?
       Angela Merkel. Phd quantum chemistry. Conservative femail politician, pro action on global warming.
58522. Bob Lacatena at 00:57 AM on 20 May 2012
       CO2 lags temperature
       Dougal, On the graphs, "temperature change" means increase or decrease from a chosen baseline (our current climate). The data is from this paper by Petit (2000) and is done by proxy (O18 isotope levels), and as such is relative to current O18 isotope levels (which are indicative of current temperatures). This is why it is presented as "difference from today" rather than an absolute value, because what is being used to present the data is a difference, not an absolute, in something else. [It's rather like measuring the change in the tide. You can see how much the water level has risen by looking at a marker on a pole, without necessarily knowing how deep the water is beneath the pole. You can confidently say the water has risen X inches -- the change -- but it doesn't really make sense to bother to try to make that into an absolute depth.]
58523. Bob Lacatena at 00:48 AM on 20 May 2012
       CO2 lags temperature
       Dougal, To translate what I just explained... there are basically tipping points. Once the ice sheets start to grow, that continues and the planet falls into a glacial state. It will remain there until a variety of orbital factors combine to toggle the system in the other direction. The rise is then fast once the change has been kick-started. I'm unsure exactly why the opposite is so gradual, except that it is really sort of the natural state of the planet (to be partially ice-covered, that is), but it takes a very, very long time to draw down CO2 once it has been increased. That CO2 blanket keeps the planet warm and the ice sheets from expanding even though otherwise the orbital configuration "wants" the planet to be in a glacial state. And with all of that said, the next orbital configuration to really get us into a true glacial state isn't supposed to be for another 10,000 to 20,000 years (it's not that easy to compute), so that at least is not really worth discussing.
58524. Bob Lacatena at 00:43 AM on 20 May 2012
       CO2 lags temperature
       Dougal,

       I would expect the gross heat effect from the Milankovitch cycles to be a maximum when closest and least when furthest (with smaller variations caused by tilt and wobble)...

       I think this points to a misunderstanding of what happens due to orbital variations. The earth does not get warmer or colder due to distance from the sun. It actually doesn't get very much warmer or colder at all due to the variations in orbit. All that changes is the length and intensity of the seasons in each hemisphere. Because the northern hemisphere is mostly land, particularly in that sensitive area around the poles (Siberia, Canada), while the southern hemisphere is mostly water, then the length and duration of the northern hemisphere summer becomes key. If summer is too short and cool, then ice sheets can grow and expand in the NH. These reflect a lot more of the incoming sunlight than either open water, tundra or vegetation covered land. That actually changes the temperature of the planet and cools it off. Conversely, when the axial tilt and other factors conspire to lengthen/strengthen the NH summer, the ice sheets will have longer to melt and less time to grow back in winter. The earth will absorb more sunlight/energy (instead of reflecting it back into space). This will warm the earth, and add to the retreat of the ice sheets. Then CO2 adds its punch on top of that.
58525. Bob Lacatena at 00:38 AM on 20 May 2012
       CO2 lags temperature
       Dougal, I'll answer your post in parts, because it is so long. I'm not entirely sure I understand all of what you're saying, because you seem to include some misunderstandings in there. First, the simple and most important point:

       What I am missing is why the extra man-made forcing is such a critical factor for earth's climate.

       Because the amount of carbon available to the system has been well constrained in the last 800,000 years to pretty much stay below 300 ppm, even at peak. There simply wasn't enough carbon to go around for feedbacks to keep adding CO2 beyond that. It took man, digging up 337 Gt of carbon (and counting) that had previously been sequestered underground in fossil form to provide a source of carbon that would allow levels to rise above 300 ppm. A large portion of the temperature rise from glacial to interglacial is due to CO2 feedbacks due to the 100 ppm increase. So why wouldn't a further 100 ppm, 200 ppm or more greatly influence temperatures?
58526. John Hartz at 00:35 AM on 20 May 2012
       David Evans: All at Sea about Ocean Warming and Sea Level Rise
       @Rob Painting: The section header, "Not Evan wrong" confuses me. Is it correct?
58527. Kevin Hood at 00:34 AM on 20 May 2012
       David Evans: All at Sea about Ocean Warming and Sea Level Rise
       Would the infusion of frigid glacier meltwater from Antarctica and Greenland be sufficient to counter the ocean's thermal expansion to a measurable degree?
58528. Dougal at 23:47 PM on 19 May 2012
       CO2 lags temperature
       Hi, just joined the site trying to find clarification on some areas of climate change. I came here on recommendation from another forum to get info on why the CO2 lagging temperature wasn't counter to the claims regarding danger of increased CO2. I have ploughed halfway through these comments, with a couple of sidetracks along the way for linked articles. Although several of my initial questions have been answered in the article or in responses to other posters, there is a new one that either haven't been or I missed/misunderstood. If it has already been answered or are answered in the remaining comments please bear with me. I get the Milankovitch cycles and how it changes the gross heat entering the earth, and am happy with CO2 radiation absorption and vapour pressure causing oceans to release CO2 as they heat up which then absorbs more heat, which causes positive (but not runaway) feedback. I also get the difference between CO2 lagging temperature because it is a feedback mechanism, and the current man-made CO2 increase which is acting as a forcing mechanism. What I am missing is why the extra man-made forcing is such a critical factor for earth's climate. I don't mean for the effect on large numbers of species that may/will go extinct because they can not change or migrate fast enough, and I am not considering the serious issues associated with innundation of low lying areas cause by 1-2m sea level rises. But it seems from the cycles over the last 500k years, that there is some sort of feedback system that always strongly brings the temperature back down despite maximum CO2 levels for some time after the temperature starts falling. I would expect the gross heat effect from the Milankovitch cycles to be a maximum when closest and least when furthest (with smaller variations caused by tilt and wobble), so would expect the temperature, even with feedback mechanisms when both heating and cooling, to be cyclical, with the fastest change occurring somewhat after the closest and furthest approach, and the maximum and minimum to occur half way between. What I don't understand is why the change here so linear, either relatively constant cooling, followed by faster but also relatively constant heating. If there is something that can trigger such rapid (less than 1/8th cycle) changes, it must have a far more significant and powerful effect (at the turn around points) than the known feedback mechanisms I have read about so far. I assume it is either powerful (tectonics?) and/or fast (geologically) to have such a profound sudden affect. Please don't respond "it's not sudden if you expand the timescale of the graph", without explaining why the relative rate compared to the length of the cycle is not significant. All the feedback systems I know produces cyclic variations where the highest rate of change is mid cycle with lowest rate of change at the peaks - these graphs definately do not follow that norm. I would also appreciate not being asked to propose an alternative cause to CO2 (which I accept is a greenhouse gas); apart from the fact that lack of a suitable alternative idea does not validate a claim, I am here because I am not the one with the expertise. If I appear defensive, please forgive me, but these two (I believe invalid) counter arguments have been used the few times I thought this question may get adressed in the discussion. Seondly, I am confused by the label on the temperature axis for the first graph. The label says temperature change, but I assume it just means temperature, otherwise zero would be nearer the middle?
58529. muoncounter at 22:45 PM on 19 May 2012
       Galactic cosmic rays: Backing the wrong horse
       ibir#125: "they might much more be able to stimulate release of a temporarily stored photons (~10um)," Muon-induced ionization does not result in photon emission: mu + atom -> mu + ion + electron (no photons here). Infrared wavelength photons (10um) are absorbed/emitted by molecular vibration. The molecules involved are GHGs: H2O, CO2, etc. Muons may interact with atomic nuclei, but not with such molecules. So that is not a valid mechanism either. Look at it this way: if muons interacted with greenhouse gas molecules, their flux rate at sea level would be a GHG detector. It isn't.
58530. Rob Painting at 21:47 PM on 19 May 2012
       David Evans: All at Sea about Ocean Warming and Sea Level Rise
       chriskoz - halosteric are the changes in ocean salinity (saltiness) which affects the density of seawater and, ultimately, sea surface height.
58531. Bob Lacatena at 21:14 PM on 19 May 2012
       Polar bear numbers are increasing
       matzdj, This issue is very simple. If warming continues unabated then eventually Arctic ice will melt for some or even large parts of the summer season. If this happens it is a destruction of the polar bear habitat for a very important part of their annual life cycle... it will shorten a hunting season that was already abbreviated by summer ice melt in 1970s conditions. For a human being, it would be like having a killing drought in August on every farm, every year for the next several hundred years (at a minimum). If you destroy an animal's habitat it will die or migrate. If it has nowhere to migrate, the only choice is to die... or to adapt and evolve, but I'm not sure that can happen when the habitat changes or disappears so quickly, and in any event, what would emerge would no longer be a polar bear. All of the evidence, no matter how sparse, points to a decline in polar bear populations, which is in keeping with all of the other science and observations (physics says the globe should warm, measurements show the globe is warming, measurements show the ice is retreating earlier and further each summer, etc.). But what really matters at this point is a measure in the change in habitat. One does not, after all, start to worry about drowning only when the water is already filling one's lungs. It helps to consider how deep the water is before diving in. Consider this report from the U.S. department of the Interior, which provides these graphs adapted from Durner et al 2009 (Predicting 21st-century polar bear habitat distribution from global climate models).

       Observed changes in the spatial distribution of optimal polar bear habitat from 1985 through 1995 to 1996 through 2006. The map shows the net change in the number of months per decadal period where optimal polar bear habitat was either lost (red) or gained (blue).

       

       Projected changes (based on 10 IPCC AR-4 general circulation models [GCMs] run with the SRES-A1B forcing scenario) in the spatial distribution of optimal polar bear habitat from 2001 through 2010 to 2041 through 2050.

       Consider these other recent studies: Projected poleward shift of king penguins' (Aptenodytes patagonicus) foraging range at the Crozet Islands, southern Indian Ocean Monitoring sea ice habitat fragmentation for polar bear conservation Rebuttal of "Polar Bear Population Forecasts: A Public-Policy Forecasting Audit" In the end this all falls back, as usual, on the typical denial cry of "but it hasn't happened yet." Like most things related to climate change, however, if you can unequivocally prove that it is happening, then it is already too late. The climate will have gone too far, and there's no chance to stop it. This is the true danger of climate change. Climate change is slow. Historically, it takes thousands to tens of thousands of years. We're doing it in a geologic blink of an eye, but on human time scales it is still "glacially slow" (pun intended). But the CO2 we add to the atmosphere now commits us to a future that we cannot reverse. The CO2 we have added to the atmosphere has already committed us to a future that we cannot reverse. It bears repeating (that pun was unintentional): Like most things related to climate change, however, if you can unequivocally prove that it is happening, then it is already too late. This is true of polar bears. It will be true of many habitats and species that may be impacted by climate change, such as the Amazon, coral reefs, and many, many more. As thinking beings, we have two abilities that exceed those of other animals (like polar bears). One is to think and to project and to plan, to take what we know about how the world works, put 2 + 2 together, and realize what is likely to happen. The second is to look at what data is available, even for things that have not yet happened, and to make reasonable projections. This applies to every aspect of climate change. Loud cries of "but it hasn't happened yet" are made to prey upon those who are too stressed and tired about other, immediate problems in their lives to bother to think ahead. Thank goodness some people don't take such a conservative, short-sighted and ultimately failed approach towards how we manage our civilization and our lives.
58532. chriskoz at 20:30 PM on 19 May 2012
       David Evans: All at Sea about Ocean Warming and Sea Level Rise
       The SLR on NODC website you're quoting is split into "theremosteric" and "holosteric" component. I found the definition of "theremosteric" online: it's as the name suggests the expansion due to change in T, other params (i.e. p) being constant. Howener the meaning of "holosteric component" evades me. I found some laconic definitrion of holosteric as "wholy solid", which does not make sense in our context as water is obviouslyt not solid. Can anyone explain to me the meaning of this component of SLR and why it is shown on NODC website as slightly negative (-1 to -2mm) for both shallow and deep ocean? Thanks.
58533. les at 18:56 PM on 19 May 2012
       Galactic cosmic rays: Backing the wrong horse
       125 - ibir Physicist or not, you're speculating about physics and need a certain amount of background. First you said "not strong enough to create 'air ions'" now "able to strip electrons"... Molecules with stripped electrons are ions. etc. naybe there should be a post with more fundimental phulysucs concepts .. But, really, a good go at wiki is a mInimum and you could try to point a physics mechanisms outlined there.
58534. ibir at 17:55 PM on 19 May 2012
       Galactic cosmic rays: Backing the wrong horse
       123 - les As a non-physicist, the maths is far beyond my skill, and, I wasn't thinking so much about Cherenkov radiation, just that when the charged muons are able to strip electrons from atoms/molecules, when flying by in relativistic speed, then they might much more be able to stimulate release of a temporarily stored photons (~10um), earlier then by chance anyway.
58535. R. Gates at 15:54 PM on 19 May 2012
       David Evans: All at Sea about Ocean Warming and Sea Level Rise
       This is an excellent counter to David Evans and his cherry-picked denialist nonsense. The focus here on ocean heat content is spot on. You might want to update your 2000m graph as the latest data for Jan-Mar 2012 Is in and ocean heat content down to 2000m is at an all-time instrument record high. It is nearly impossible for skeptics to explain this away, so they can only discredit it or focus on the tropospheric temps. With Solar max 24 coming next year (no matter how weak) and a likely El niño in the next year or so, tropospheric temps should be hitting record highs as well. Skeptics will have to work harder to find cherries to pick, but expect folks like David Evans to be bringing us his little baskets filled as much as he can for as long as there are gullible and receptive minds to consume his psychotropic cherries.
58536. skywatcher at 13:43 PM on 19 May 2012
       Polar bear numbers are increasing
       

       Those projections are based on what will happen if all the ice melts. That's like saying that we are in trouble if the sun becomes a supernova, and then worrying about it.

       To raise a general point here - there is very strong evidence that summer sea ice is on a strong and accelerating decline (see appropriate threads). There is little doubt that sea ice will continue to retreat, most likely to seasonally ice-free Arctic within a few decades. The consequences are generally agreed to be a bad thing for the polar bear populations that rely on hunting on the sea ice. If you don't think sea ice is both thinning and retreating, and accelerating in its decline, discuss on an appropriate thread with your evidence. Conversely, there is no evidence that the sun will become a supernova. In fact the current consensus in astronomy is that the Sun is too small to ever become a supernova. Even if all the matter in the Solar system was condensed into a white dwarf, the degenerate star would not have enough mass to become a Type 1a supernova, and of course the Sun lacks a stellar companion to give the extra mass required to cross the Chandrasekhar Limit (about 1.4 solar masses) to make a Type 1a supernova. Other supernova types require even more mass. One idea is supported by nearly all the evidence we have, the other has no evidential or theoretical support whatsoever. Why would you make such a comparison?
       Moderator Response: TC: "IFF" is an abbreviation for "if, and only if". "IF" on the other hand is only a violation of comments policy. Your future compliance with that policy is appreciated.
58537. scaddenp at 12:50 PM on 19 May 2012
       Polar bear numbers are increasing
       " Shouldn't we be applying those resources to problems that we know exist" Yes, we should. And despite your attempts to deny, without scientific foundation to support them, dealing with climate change is one of them and quite possibly the most important one. At very least it will many other problems worst. Please try looking at the evidence instead of trying to warp reality to fit a what appears to be a preconceived notion about the reality of AGW.
58538. scaddenp at 12:44 PM on 19 May 2012
       CO2 limits will harm the economy
       So Helena, I take you agree that killing the subsidies is a good start, (you still seem to assuming that absence of data in the online database for developed countries means that most of subsidies are elsewhere,despite the OECD figures.) And lets not have high school debating tricks please about ducking the substantive question.
58539. Daniel Bailey at 12:26 PM on 19 May 2012
       Polar bear numbers are increasing
       Using matzdj's logic one should let all bank robbers get away because not all bank robbers will actually leave the premises with the money after the teller hands it to them... Needless to say, matzdj's argumentarium is bereft of substance and replete with strawman rhetoric. matzdj, this website is an incredible resource for those actually interested in learning about climate science. For those of other persuasions, it is a tempting target. The choice of which path you are here to trod is before you now.
58540. matzdj at 11:44 AM on 19 May 2012
       Polar bear numbers are increasing
       JMurphy, I stand corrected. I had taken that population of 5000 in 1950 as accepted data. I didn't understand that it may only have been a WAG. I guess we don't have a number to compare today's number with. The recent analyses from the PBSG group but seems to be reasonably well founded, although limited, at being around 20-25,000 Bears. However, their projections don't seem to based on that data, but on the fear of what might happen if all the ice melts. I think that defines a WAG. On the pbsg.npolar.no you can see the population status maps with comments. Davis Strait has about 10% of the total population and their comment is: "Population size of 2150 estimated using mark-recapture in 2007. Subpopulation likely increased over the last 30 years. Empirical birth and death rates suggest population is now declining." So the best data that they are willing to describe shows a likely increase. But a sample of birth and death rates (apparently too small a sample to document or lead to an updated population report) "suggests" the population is now declining. That led to a rating of Very High Risk of Future Decline. Boy that sounds like a weak reason to make such a strong projection. If there is more science or more data, why don't they describe it. I'm sure this group is doing good scientific work. However, they should limit their reporting to the data they have and how it projects. Now how it might project if something else changed. skywatcher and Composer99, I would like to stick with the science. The science from the PBSG is in their evaluation of the populations. i don't argue with that. But, If they were making projections solely based on the data they report, it is unlikely that they would come to the projections they discuss. Those projections are based on what will happen IF all the ice melts. That's like saying that we are in trouble if the sun becomes a supernova, and then worrying about it. I've been getting beaten up on other threads on this site because I am believe I saw something visually in the data that a statistical analysis didn't show because it averages things out. Where is the statistical analysis of the Polar Bear population that can be used to project their decline? scaddenp, I apologize for the rhetoric. What i was trying to say was that we have a limited amount of resources to apply to solving problems. Shouldn't we be applying those resources to problems that we know exist and that we can solve and will have benefit, instead of problems that we project because the data "suggests" that the problem "may" occur if some other event occurs. Let's keep watching the Polar Bear data and if it does ever show a decline in Polar Bear population, then we can consider worrying about it. Rob Honeycutt, (-snip-) Dave
       Moderator Response:

       [DB] The topic of this thread is Polar bear numbers are increasing, not changes in sea-ice-extent minimums (cf this post on Kinnard et al 2011) nor about the opening of the Northwest Passage (another must-read is this post on Arctic sea ice extent).

       Off-topic snipped.

58541. Rob Painting at 11:20 AM on 19 May 2012
       David Evans: All at Sea about Ocean Warming and Sea Level Rise
       jsam - fixed thks. mfripp - not sure what you mean by 'human-generated heating', but the text has been slightly adjusted in any event.
58542. Martin A at 09:25 AM on 19 May 2012
       CO2 has a short residence time
       IanC: Thank you for clarifying. Yes, I had been assuming linearity. None of the statements I had seen (eg "the adjustment time is essentially independent of the residence time") mentioned that they no longer apply if you assume linearity. Dikran M's paper uses linear systems as examples (if I have understood his paper correctly). He uses an example of a wash basin to explain the principle. I worked out the equations that describe it, assuming its outflow is proportional to the volume of water it contains. We have a wash basin, with: * i litres per minute flowing into it. * v(t) litres in the wash basin at time t minutes. * Outflow k v(t) litres per minute. (Note: outflow proportional to v(t) for linearity.) The equation for v(t) is then dv(t)/dt = -k v(t) + i Residence time In equilibrium (ie at t=infinity), dv(t)/dt = 0, so 0 = -k v(infinity) + i so v(infinity)/i= Residence time = 1/k. Adjustment time Consider the wash basin in equilibrium and then, at t = 0, dump an additional D litres of water into it at t = 0. The equation for v(t) is, as before, dv(t)/dt = -k v(t) + i, but with v(0) = D. This has solution v(t) = i/k + D exp (-k t) so the deviation from the equilbrium is d(t) = D exp(-k t) . This means that the adjustment time (ie for the transient to decay to 1/e of its initial value) is 1/k. Adjustment time = 1/k. So it seems that in the case of a linear model, at least one with a 1st order differential equation, residence time = adjustment time. And presumably, with some nonlinear models this may also apply? If you assume finite volume for the ocean, even with a 1st order linear model, the equilibrium changes after the injection of a mass of CO2 into the atmosphere. This means that a proportion of the released CO2 remains in the atmosphere forever (according to the model) - but I think that is different from saying that the residence time and the adjustment time are not equal.
58543. Jose_X at 09:06 AM on 19 May 2012
       Dear Heartland, Stop using Arthur Robinson's Trick to Hide the Incline
       > >Regarding the world data. We clearly labeled this data location. Since virtually all other available dats (sic) from other locations (see Soon and Baliunas) is similar, providing this example was entirely ethical. Has someone followed up on this? [I haven't.] I wonder if doing the average on these studies would produce a mean similar to the pictured one. I think many MWP proxies do not line up temp with years, leading to wide error bars and lukewarm means. If that is the case here, then taking this one sample might not be "ethical" or accurate as concerns the implied depicted suggestion that the temp has clearly been higher in the recent past.
58544. jsam at 06:10 AM on 19 May 2012
       David Evans: All at Sea about Ocean Warming and Sea Level Rise
       Typo alert. In "Evans can pretend the incoveniently long" there is an "n" missing, inconveniently.
58545. mfripp at 05:07 AM on 19 May 2012
       David Evans: All at Sea about Ocean Warming and Sea Level Rise
       Albatross, we are in agreement. Nonetheless, it would be best if we avoid statements are inaccurate. Especially if it is easy to avoid such statements.
58546. Geo77 at 05:00 AM on 19 May 2012
       Dear Heartland, Stop using Arthur Robinson's Trick to Hide the Incline
       I will definitely bookmark this post for future reference as an example of what constitutes denialism versus true skepticism. I hope that your work here will find it's way into the curriculum of some "methodology of science" type courses. You have provided an excellent and well documented example of how science should not be done. Or should we just call it anti-science, or in a nod to Seinfeld - science in the bizarro world?
58547. IanC at 04:56 AM on 19 May 2012
       CO2 has a short residence time
       For more general functions for fluxes, X/F(X) and 1/F'(X) will probably be very different.
58548. Albatross at 04:55 AM on 19 May 2012
       David Evans: All at Sea about Ocean Warming and Sea Level Rise
       mfripp @1, "There is volcanic activity as well as human-generated heating" True, but the magnitude of these terms is tiny compared to the incoming solar radiation. See "Heat from the earth's interior does not control climate" and "It is not waste heat". But let us not get distracted from the real issue. There real issue is Dr. Evans misrepresenting the data by cherry picking the data and ignoring corrections to the data etc. One has to wonder that had the corrections been in the direction of "cooling" whether they would have also been ignored by Evans? Surely he should know that no data are perfect (even the temperatures inferred from satellite MSU data and the ARGO data as Robert notes) and that all data have limitations and require corrections of varying degrees. "Skeptics" like to hold others to a very high scientific standard, as they should, but what is disconcerting is that Dr. Evans' video strongly indicates that "skeptics" are not willing to hold themselves to those same high scientific standards. Them failing to do so flies in the face of their claim about being true skeptics.
58549. IanC at 04:48 AM on 19 May 2012
       CO2 has a short residence time
       @118 MartinA, I suspect the discrepancy is due to the use of a linear model to describe a process that is likely to be highly nonlinear. I think there is nothing wrong with trying to understand it via a linear model, provided that you interpret the results with care. Using X for atmospheric CO2, and Y for ocean CO2. The differential equations are dX/dt= -F(X) + G(Y) dY/dt= F(X) - G(Y) With F(X) and G(Y) being fluxes out of the atmos and ocean respectively. In your scenario, you initially assumed that the system is in equilibrium and then perturb X to determine the response. Suppose the system is initially in equalibrium (X*,Y*), i.e. F(X*)=G(Y*). Linearising the above system I'll get d(X-X*)/dt= -F'(X*)(X-X*) + G'(Y*)(Y-Y*) d(Y-Y*)/dt= F'(X*)(X-X*) - G'(Y*)(Y-Y*) The implication is if you want to treat the problem as a linear one, the time constants are actually given by derivatives of the fluxes with respect to concentration, i.e. how sensitive the fluxes are to a change in CO2. The equilibration time scale is given by 1/F'(X*). On the other hand, the residence time or lifetime is defined as as capacity divided by the flow rate, in our case at equilibrium is given by X*/F(X*). Intuitively this is sensible: if we have 100 tons of CO2 in the atmosphere, and it is entering the ocean at a rate of 100tons/day, it'll take about a day to clear the atmosphere of CO2. Now if the flux F(X) is linear in X as in your model, the residence time and equilibration time is exactly the same! The fact that you can't get a separation between the two timescales is due to your choice of F(X) and G(Y).
58550. Martin A at 03:49 AM on 19 May 2012
       CO2 has a short residence time
       KR"The important thing to remember is that regardless of residence time, the vast majority of CO2 molecules entering the ocean are simply swapped with another molecule." Yes, completely agree. And if the system were in equlibrium, 100% of entering molecules would be swapped for an exiting molecule. "The rate of importance is how fast total concentration (not individual molecular identities) changes." Completely agree with this too. (...) At present I'm trying to understand simple idealised cases - I'm avoiding realistic situations as there are too many extra things to cause confusion. I'm working through DM's paper at the moment. "Again - the residence time is not directly related to the sum flow into and out of climate compartments, the adjustment time. That comes from the differences between flow rates." Again, I agree. Yet something does not add up for me and I reach a different final conclusion. I'm going to track it down - I promise.

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