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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 82001 to 82050:

  1. McManufactured Controversy
    This controversy is not about the facts or about science. It’s about the perception of the impartiality of the IPCC: it’s politics and PR. Frankly, I’m amazed after all the controversy that the IPCC has faced in the past few years that they believed that they could maintain an aura of impartiality while including a Greenpeace employee as a Lead Author. The prominent Canadian skeptic who is a master of making McMountains out of molehills plainly goes too far when he calls for all WG3 contributors to be terminated. On the other hand, it’s an error, I think, to maintain that there’s nothing that needs to be fixed at the IPCC, especially when it comes to reports on the fields of research outside the physical sciences. Among large sectors of the public, Greenpeace has a reputation as a strident militant organization, more concerned with publicity-seeking, high-profile stunts (for example in Greenland or in Turkey), rather than being a research organization, devoted to following the facts diligently, wherever they may lead. Obviously, that’s not the way that many at the IPCC see it. According to Oliver Morton —“Babbage”— in The Economist (making the case more strongly than I would):
    The world of renewable energy has a very strong party line, based on a belief in its moral superiority and ultimately inevitable triumph. In this world Greenpeace doesn’t look fantastical, shrill and occasionally criminal, as it does to many in business; it seems a “stakeholder” among others. And it is in this world that most of those who study and profit from renewables, not to mention a lot of those who set relevant policies, are likely to spend their days.
    Yes, being suspicious of an author’s contribution based on where he is employed is an ad hominem argument, but when it comes to trust and reputation, guilt by association trumps the rules of logic, especially in a world where few people are able to sort through the details but everyone can see where the authors’ pay checks come from. For the WG2 and WG3 areas of research, it’s inevitable that non peer-reviewed “grey” literature is going to have to be referenced. Also, many of the experts in these areas are employed by energy companies, industry lobby groups and NGO’s; preventing them from contributing to the IPCC process would not be desirable, since a big fraction of the latest expertise would then be excluded. Commercial interests and political agendas are hard to unscramble from the basic technical research in any discussion on the merits and challenges of emerging technologies. Therefore, to maintain its reputation as a source of reliable and unbiased summaries of the state of knowledge, the IPCC surely needs to adopt particularly strict standards on possible or even just perceived conflicts of interest in these areas. At the very least, surely, employees of highly politicised advocacy organizations like Greenpeace should not be appointed as Lead Authors. It’s true that no fuss has been made about the participation of oil company employees to the SRREN, but most of them were not Lead Authors, and contributions with obvious big oil provenance were not prominent in the report nor highlighted in the IPCC press release. It’s no use just saying that the facts are all on the IPCC’s side; as the Skeptical Science blog repeatedly shows, contrarians lose every battle in the scientific arena. The AR4 WG1 report is beyond reproach. Yet, judging from the negligible progress we have made in arresting emissions, the inactivists are nonetheless winning the war. In Canada and the US, our leaders can scarcely bring themselves to utter the words “climate change”. The expansion of the tar sands in Canada is a major driver of economic growth; the largest and growing export from Australia is coal. In times of economic uncertainty, winning over the public to the idea that we have to shut down these industries over the next decade or two requires a compelling narrative and scrupulously unbiased information backing it up. To quote George Monbiot (from faulty memory), we need to do better than say that: “providing we radically restructure our economy, then the climate won’t be as bad as it otherwise might have been”. Against this we hear the misleading but more easily digestible: . “And now Greenpeace is writing the IPCC reports”
  2. The Planetary Greenhouse Engine Revisited
    Michele, sorry, no, that's not right at all. CO2 optical thickness decreases roughly exponentially away from the band center. With optical thicknesses of intermediate value, a thick layer of air emits to space, or in any direction from any level (a thicker layer of the upper troposphere, potentially extending to and including the surface, will be the source of radiation upward at the tropopause, for example). Not that it's impossible to have a convective layer aloft, but this just isn't the case for the mesosphere. The CO2 band actually encompasses somewhere on the order of ~ 30 % of the blackbody radiation in a spectrum for temperatures in the range of the surface and most of the atmosphere. This includes parts where the atmosphere is partially transparent, though. Radiative forcing: When you increase the density of a component with cross section (opacity), cross section density, optical thicknesses over the same paths increase in proportion. The distances photons can travel shrink. The emission weighting functions become more concentrated and overall closer to the location for which they are based. With a potential for some variation when starting with great transparency, eventually the brightness temperature approaches the actual temperature; if there is not a disconinuity in optical properties or temperature, the net flux goes to zero. (At the effective TOA, an effective discontinuity, the net upward flux is just the upward flux.) The net upward LW flux at the tropopause must (global annual average, in the approximation of zero convection across the tropopause) balance the net downward SW flux, equal to solar heating below that level, or else energy is being gained or lost from the troposphere+surface. Where CO2 is saturated at the tropopause level, the net flux is already zero and can't be farther lowered. But doubling CO2 approximately shifts the same range of optical thickness values out from the center of the band, into where the atmosphere was more transparent. This reduces the net upward LW flux at the troposphere - for upward LW radiation at the tropopause, it 'lifts' the effective emitting level (which is just a representative concept for the emission weighting function) off the surface (if it was there) and to higher and higher levels, and for downward LW radiation, it pulls the effective emitting level from the dark of space, into the stratosphere, and lower into the stratosphere. Think of the effective emitting levels (EELS) forming a landscape; the net LW flux can be large when the EEL for upward radiation is on a warm surface and the EEL for downward radiation is in space; bringing them close together eventually makes their temperatures nearly equal and so the net LW flux goes to zero. For radiation at the tropopause level, the two EELs are, around the CO2 band a hill rising upward from the surface and/or clouds and water vapor within the troposphere, and a valley dropping down from space. When the two meet at the band center, adding more CO2 continues to widen the hill and the valley, reducing the interval of relatively larger transparency and increasing the interval where the net LW flux is zero. If the climate was previously in equilibrium, the radiative fluxes are now imbalanced, and energy accumulates below the tropopause level - until the the warming that results increases the upward LW flux (which occurs outside the saturated part of the spectrum) to restore balance. It is here where the lapse rate matters - without convection, the radiative fluxes at each level would combine to determine equilibrium temperatures; but with radiative equilibrium being unstable to (moist) convection within the troposphere and surface, the whole of the two warm to balance the radiative fluxes at the tropopause level (and at TOA) while the distribution of that warming is determined by the convective lapse rate, which itself may be temperature dependent (hence the lapse rate feedback), and from various other complexities that arise when considering the full 4-dimensional climate system. I have up to this point skipped the effect on the stratosphere; adding CO2 cools the stratosphere, due to a combination of the temperature profile being as it is and the spectra being as they are. The stratosphere has little heat capacity relative to the convectively-coupled troposphere+surface (including the ocean, or at least the upper more rapidly mixed portion of it) and tends to reach radiative equilibrium much faster. This reduces the downward flux at the tropopause level, having a cooling effect, and so rather than using 'instantaneous forcing', we often refer to the tropopause-level forcing with stratospheric adjustment - this is the forcing that the tropopause+surface must respond to. However, there is also a feedback when the warming below the tropopause increases the upward LW flux, as some of that is absorbed by the stratosphere, increasing the LW flux emitted by the stratosphere by that amount, some of which is downward - however the stratosphere on Earth is relatively transparent to much of the LW radiation upward from below, perhaps even more so to the increase in LW radiation. I
    Response:

    [DB] I took the liberty of breaking your comment up into paragraphs for improved readability.

  3. Eric the Red at 04:36 AM on 22 June 2011
    How would a Solar Grand Minimum affect global warming?
    This popped up over at RC, comparing the long-term European temperature records with the global datasets. http://www.imagenerd.com/uploads/co2_temp_1650-2010-6OeMR.gif
    Response:

    [DB] This is part of JBob's long-standing efforts to counter known global effects with local measurements.  It is meaningless and has little if any bearing on the topic of this thread.

  4. Infographic: 97 out of 100 climate experts think humans are causing global warming
    Eric the Red - I believe the content of your last post (you have a duplicate there, don't know which one the moderators will leave) was fully stated earlier in your previous post, or possibly this one. They certainly were not deleted. You've received several answers since then, with Tom Curtis's probably the clearest. Median values (not means, but the 50% median, very important in asymmetric distributions) cluster strongly at 3C, with only one of the AR4 median values more than 1C away. Recent instrumental estimates have higher variability, which isn't surprising since they won't have enough data/timeframe to clearly estimate long term feedbacks. When you have independent measures (different proxies, instruments, models, etc.) that all produce similar results, the uncertainty decreases with each additional estimate, not increases. 3C per doubling of CO2 is a very solid value. It would be interesting to apply Annan and Hargreaves methods for Bayesian inference to the full set of estimates, rather than just three, and see how tight a limit the full set of experiments constrains that sensitivity. "I don't know why politicians should bet on low, high, or mid-range climate sensitivity values, as they all have a high probability of being wrong. " Politicians should bet on the most likely numbers, as they have the highest probability of being right. Again, your attitude strikes me as a "Yes, but..." form of denial, and in particular of delay of action.
  5. Climate change denial and the abuse of peer review
    Joshua, it is true that plagiarism does not "necessarily" indicate a lack of veracity in other matters, but it certainly begs the question. In any case, the problems with Wegman's report fell more into the category of 'political spin' than factual inaccuracy. That is... he noted that various authors had worked together on various papers... and then implied that this suggested a dark conspiracy and failure to properly check results. True factual statement, completely bogus implication. The Wegman and NAS reports contained virtually all the same observations... and based on these reached diametrically opposed conclusions.
  6. Eric the Red at 04:20 AM on 22 June 2011
    Websites for Watching the Arctic Sea Ice Melt
    That is a strong statement. Do you have any evidence to support it?
    Response:

    [DB] "I shall be telling this with a sigh
    Somewhere ages and ages hence:
    Two roads diverged in a wood, and I,
    I took the one less traveled by,
    And that has made all the difference."

    Volume

    [Source]

  7. Websites for Watching the Arctic Sea Ice Melt
    Eric, extent isn't a particularly useful metric except for determining trends over a long time period. As DB notes, volume is the defining factor... though unfortunately much more difficult to measure. Extent = area / average concentration From this simple formula it is clear that extent is as much determined by how spread out the ice is as by the amount of ice surface... and it completely ignores how thick it is (and thus how much energy is required to melt) Volume = area * average thickness Comparing this formula to that for extent we can see that extent is essentially a proxy for volume with two potential error factors (no thickness component and variable concentration). The lowest extent was in 2007 and at the time that was also the lowest volume, but volume in 2010 was significantly lower and thus far volume this year has been lower than 2010. With the two 'error factors' it is still possible that the 2007 extent will not be broken, but as the volume continues to drop it becomes less and less likely.
  8. Climate change denial and the abuse of peer review
    What say you to the oft heard response that Wegman's plagiarism doesn't necessarily detract from the veracity of his analysis?
  9. Eric the Red at 04:13 AM on 22 June 2011
    Infographic: 97 out of 100 climate experts think humans are causing global warming
    I will try again, since the moderater insists it will work. The studies do not suggest thatthe values are centered close to 3. In fact, they suggest the opposite. Models show clustering around three, will paleo data consistently shows higher values with temperature data showing lower. There are several clusters of estimates, without a smooth distribution. KR linked to a nice series of climate sensitivity papers. So far, I have only read through the first two pages. Some papers show higher climate sensitivity ranges; Sanderson 2.45 - 7.32 and Hergerl 1.5 - 6.2, while others show lower; Schneider 1.08 - 2.3 and Padilla 1 - 3.2 (do not ask me how anyone can list three sig. figs. in their determinations). Risk analysis may be fine for policy makers and insurance agents, but makes for poor scientific study. I would not advise anyone to accept a mean value (3.0) or median value (2.6 or 2.8) in making decisions when such a wide range exists. It may be a good starting point, but one should realize that it could be off by a large amount. I do nto know why politicians should bet on low, high, or mid-range cliamte sensitivity values, as they all have a high probability of being wrong.
  10. Rob Honeycutt at 04:10 AM on 22 June 2011
    IPCC Report on Renewable Energy
    Dana... But that whole equation is supposed to flip sometime in the next decade, right? I keep reading that PVs are projected to fall below the cost of coal this coming decade, even without subsidies.
  11. IPCC Report on Renewable Energy
    luminous - that's a bit of a tricky question, because it depends what you're factoring into the price of a new coal plant. In this post I mentioned the true cost of coal power - in short, the market price is cheap because it doesn't reflect the costs of the climate change and impacts on public health (which economists call "externalities"). If you don't include those external costs, coal is cheaper than most renewable energy sources (onshore wind is close). If you do include those external costs, most renewable sources are already cheaper than new coal plants. Putting a price on carbon emissions would be a major step in making the market price of coal more accurately reflect its true cost. Basically in the real world, it's cheaper to replace old power plants with renewables. But in the current market, it's usually cheaper for an electric utility to replace them with new coal plants (or natural gas). Which is why so many of us (including most economists) are pushing for a price on carbon emissions.
  12. thepoodlebites at 03:59 AM on 22 June 2011
    How would a Solar Grand Minimum affect global warming?
    I just read an interesting article in Scientific American, March 2011, A Shifting Band of Rain. There's a good reconstruction of the Northern Hemisphere temperature anomaly during the Little Ice Age, about -1.0 C cooler than present. Here's an interesting observation from the article, "when solar energy reaching the top of the atmosphere decreased by just two tenths of a percent for about 100 years, the ITCZ migrated south toward the equator by 500 kilometers." The prediction is another 500 kilometer migration to the north by 2,100, based on projections from increased GHG. This prediction is pretty bold considering that the ITCZ is about where it was during the Medieval Warm Period.
  13. Eric the Red at 03:55 AM on 22 June 2011
    Websites for Watching the Arctic Sea Ice Melt
    Nice graphic. The melt pool may not be significant as the sea ice extent is essential the same as last year.
    Moderator Response: (DB) The volume is what matters; by melt season's end, 2007 will fall.
  14. McManufactured Controversy
    While generally rather ignorant of Australian politics, it's my understanding that they are ramping up to vote on a carbon tax. This would be a significant move towards controlling CO2 emissions - a major country investing in controlling their GHG footprint. Given that, it's not all that surprising that various "skeptic" sources are ranting loudly; JoNova, Watts, assorted 'Business as Usual' associated mouthpieces, etc. While not confident about it, I'm hopeful that the increasing rant level, decreasing rationality of objections, and yelling about such terribly minor issues as the authorship of this peer reviewed article indicate that the deniers are beginning to run out of steam. They can still do a lot of damage in the political arena, but I believe it's becoming more and more obvious to the public that their objections are, to a great extent, hollow shells...
  15. Climate Change Denial book now available!
    This use to be available as a pdf download right? where is that gone? I have been waiting for this on kindle but it is taking ages. Why is it so many environmental books dont come out on ebook for right away?
  16. McManufactured Controversy
    Keith Kloor's not fit to wipe Revkin's shoes, in terms of influence, so I didn't bother mentioning him. I think Revkin's definitely worth pointing out, though, since he's possibly the most prominent NY Times voice on climate change issues and has a long standing track record of using folks like RPJr as his go-to source on the science (rather than, well, climate scientists).
    That's how the integrity of the attacks is being presented: one possible flaw, even though tiny and not central to the findings, is cast as evidence that the entire document is fatally flawed.
    Not just the document, but the entire IPCC. That's what they're after, bringing down the IPCC. Never mind that WG3 is much less rigorous than the most important working group, WG1, which analyzes and summarizes the state of the science. If you can undercut one group's work, even a small part of it, even on points which have no merit, you can undercut the entire process or even kill it entirely.
  17. actually thoughtful at 03:43 AM on 22 June 2011
    Linking Extreme Weather and Global Warming
    It is a small point, but part of the rise in insurance claims is a trend (in the US at least) for increased population densities where climate change driven disaster is likely (and, per Tom Curtis, that is everywhere), specifically the forest urban boundary in the West/Southwest, along rivers, and along shorelines. However, this trend is minor compared to the impact of increased energy and moisture in storms. I appreciated the idea that the lower differential in temperatures that global warming brings should translate to weaker storms, but the observable reality (see Tom Curtis at 116) actually indicates the opposite.
  18. McManufactured Controversy
    dhogaza: "The very URL exposes his error: "new-ipcc-error-renewables-report-conclusion-was-dictated-by-greenpeace" DSL: "Further, he has, like Watts, allowed his comment stream to fill up with garbage and shown an unwillingness to address the garbage." Lynas has also shown an unwillingness to address critique of his arguments. I tried multiple times to point out the obvious problem with the headline (that dhogaza linked to) and other arguments on his blog, but to no avail. Then he comes back with the "circle the wagons" response to characterize anyone dissenting from his argument. End of discussion. Minor issue with Dana's point: "And unfortunately, a few other influential figures (i.e. Mark Lynas and Anthony Watts) have bought into McIntyre's glaring logical fallacy." Watts would predictably buy anything that bashes the IPCC, so that's not a matter of chance.
    Response:

    [dana1981] Agreed re Watts, but it's still unfortunate

  19. When scientists take to the streets it’s time to listen up
    Eric the Red - While a few "test" posts appear to have been deleted, I don't see any of your posts with content that have been removed. Certainly there don't seem to be any posts containing examples of misrepresented papers (as you claimed earlier), as per dhogaza's or my questions, that have been deleted. But I'm not a moderator, perhaps I've missed something. I would suggest (re)posting your examples, paying attention to the Comments Policy while doing so.
    Response:

    [DB] You are correct, on all counts.  You haven't missed anything, O' Sharp of Eye.

  20. luminous beauty at 03:37 AM on 22 June 2011
    IPCC Report on Renewable Energy
    A question that always arises in my mind is: What is the difference in the investment cost of renewables and the investment cost in replacing existing fossil energy plants, plus the infrastructure that supports them, as their economic lifetime expires? I hardly ever see this addressed except that renewable plant costs are, in general, going down and fossil plant costs are going up. I also note that the geothermal sources are conservative low hanging fruit estimates compared to the MIT study that gives estimates of 14,000ZJ, 200ZJ - 2000ZJ potentially extractable, for just the continental US. To coin a phrase; What's Up With That?
  21. IPCC Report on Renewable Energy
    Lynas has not raised any substantive criticisms of the report. He's unhappy that the 77% plan phases out nuclear power, but that's neither here nor there - the plan is both technically and economically feasible. As Rob suggests, to discuss the manufactured controversy and ad hominem attacks, please see the sister post linked at the end of this article.
  22. McManufactured Controversy
    Eric #1 - it's pretty clear that McIntyre has been the leader of this manufactured controversy, and Lynas jumped on his bandwagon, though he may have taken it further. dhogaza - true, Revkin's initial reporting on the subject was quite poor. If we were making a list, we could also include Keith Kloor, from what I've heard (I haven't visited his site recently). But I didn't intend to make a list, just to provide a few examples of poor vs. good coverage of the subject. And it's certainly not even remotely true that Greenpeace dictated the conclusion of the report.
  23. McManufactured Controversy
    Eric, Lynas has echoed the sensationalism--indeed, I might say alarmism--of McIntyre. Further, he has, like Watts, allowed his comment stream to fill up with garbage and shown an unwillingness to address the garbage. When the larger context is understood--as dana points out--then the strong reaction to it ("more of the hoax!") appears not only uncritical but a little insidious. We might use the analogy of the dam here: critics are looking for the slightest, tiniest crack in the dam, because small cracks can become large cracks and lead to the complete failure of the dam (AGW). That's how the integrity of the attacks is being presented: one possible flaw, even though tiny and not central to the findings, is cast as evidence that the entire document is fatally flawed. Yet the IPCC report is not a dam. It is more like a forest. Teske et al. (2010) was peer reviewed, but if it still represents a conflict of interest, if you think (without evidence presented ("exposing the conflicts")) that it's still a flaw in the process, then it is a tiny flaw--one plant in the forest. If the plant dies, the forest still lives (indeed, it grows stronger on the decomposition of that plant). It's rather more interesting that McIntyre, Watts, and their comment-bots need to seize upon and seriously misrepresent this rather insignificant element of the report. Given the context, it doesn't just suggest desperation; it is desperate.
  24. McManufactured Controversy
    "I would suggest reading the full article before posting" It would be nice, wouldn't it? Just as it would've been nice if Revkin had read the report he was criticizing before jumping on the "IPCC == greenpeace == evil" bandwagon.
  25. McManufactured Controversy
    I would say that Mark Lynas is full of it. The very URL exposes his error: "new-ipcc-error-renewables-report-conclusion-was-dictated-by-greenpeace" That's simply a lie, pure and simple. So is his claim that the peer-reviewed paper in question is "grey literature". That's just bullshit. In essence he says "I don't like the journal, therefore IMO it's grey literature".
  26. Rob Honeycutt at 03:14 AM on 22 June 2011
    McManufactured Controversy
    Eric... I would suggest reading the full article before posting. The link you're providing is already provided in the body of the article.
  27. McManufactured Controversy
    You might want to add Andy Revkin (who runs the DotEarth blog for the NY Times) to your list of sinners. "Now, it may be argued that the 77% goal is not politically realistic, but the IPCC report did not and cannot evaluate political feasibility." He fails to make that distinction and it's clear that he didn't bother to read the report before jumping on the bandwagon because he stated that the report ignored the magnitude of the investment cost that would be required if that goal were to be met. His error was pointed out to him in the comments, and he amended it, but it's the kind of error that only gets made if you've not read the report you're criticizing ...
  28. Eric the Red at 03:03 AM on 22 June 2011
    McManufactured Controversy
    I would say that Mark Lynas has been the leader in exposing the conflicts. http://www.marklynas.org/2011/06/new-ipcc-error-renewables-report-conclusion-was-dictated-by-greenpeace/
  29. Eric the Red at 03:01 AM on 22 June 2011
    How would a Solar Grand Minimum affect global warming?
    There is no current participation because my last three attempts have not registered.
    Moderator Response: (DB) Posting a comment with the sole word "Test" in it did not constitute a comment with any substance, so it was deleted.
  30. Eric the Red at 02:58 AM on 22 June 2011
    When scientists take to the streets it’s time to listen up
    dhogaza, You must have missed it. Maybe KR say it before it was deleted.
  31. Rob Honeycutt at 02:54 AM on 22 June 2011
    IPCC Report on Renewable Energy
    Eric... This is already being discussed here.
  32. Eric the Red at 02:51 AM on 22 June 2011
    IPCC Report on Renewable Energy
    Not everyone seems to think this report is accurate or even good science. http://www.marklynas.org/2011/06/new-ipcc-error-renewables-report-conclusion-was-dictated-by-greenpeace/ http://www.marklynas.org/2011/06/new-allegation-of-ipcc-renewables-report-bias/
  33. Infographic: 97 out of 100 climate experts think humans are causing global warming
    Eric the Red - Tom Curtis is quite correct. The recent instrumental estimates have a larger spread, and generally lower values, but are only capable of measuring the climate change that occurs in short time periods. Therefore they have a tendency to underestimate longer term climate sensitivity. When you have multiple independent measurements (as is the case here, as various paleo measures, modellings, and recent instrumental work are using different inputs) that each produce a similar spread of uncertainties, the uncertainty is reduced with each estimate, not amplified. The median values are tightly clustered around 3ºC. Probabilities of significantly lower or significantly higher values for climate sensitivity are extremely small. So, Eric, this makes me rather curious. You've essentially asserted (repeatedly) that we are not certain, and that more study is required. The evidence says otherwise. Why should we (in a risk management sense) not act upon the data we have? Your attitude strikes me as a "Yes, but..." form of denial, and in particular of delay of action.
  34. Miriam O'Brien (Sou) at 01:42 AM on 22 June 2011
    When scientists take to the streets it’s time to listen up
    Oh yes, I often witness deniers making up stuff and qualifying it with 'it's just my opinion' - or 'I seem to recall' - and never backing up the falsehood with evidence, obviously, because they can't. (I've been the target of such attacks myself for being an 'alarmist'.) It's a widely used tactic and I usually make the effort to counter it, because it's worth it even though it's tedious. (Same thing happens with gossipers - it's a tried and true technique throughout time immemorial probably, to start a rumour and then say 'no smoke without fire' - even though the gossiper was the one that made the smoke in the first place.)
  35. How would a Solar Grand Minimum affect global warming?
    Sorry, messed up the RealClimate link. This should work. They also link to a previous paper (Wigley et al. 1990) that is consistent with their findings. If a Maunder-like minimum comes to pass it is not going to be the silver bullet that some hope for, we still urgently need to start reducing our GHG emissions.
  36. Infographic: 97 out of 100 climate experts think humans are causing global warming
    Eric the Red @203: First, the following are the climate sensitivity studies analysed in AR4: The triangles represent the most probable individual value on each Probability Density Function, but the important value, the median shown by a circle, is the value such that there is an equal probability that the true value will be above that point, or below it, given the evidence in the study. It is quite clear that for 11 out of 15 studies with a displayed median, the median is very close (within 0.5 degrees) of 3 degrees. Only one study, Andronova 2001, shows a median more than 1 degree from 3 degrees. It is, therefore, quite plain that combining the evidence from these separate studies will result in a median close to 3. In fact, this can be seen graphically by the region in which the curves for the cumulative probability intersect: The large spread of the red curves, estimates based on 20th Century data, show such estimates to be very unreliable - primarily because temperatures do not reach equilibrium which introduces an additional source of uncertainty compared to paleo studies. Given this data from the IPCC, I would say your contention of wide divergence is refuted unless you can show such a wide divergence in more recent studies. Please not that because of the various shapes of the PDFs, giving confidence intervals does not provide us with enough information. We need to know the median values of the PDF for each estimate. Second, I note that the marking feature of climate change deniers is that that all agree that we should take no expensive action against the threat of global warming. They may claim that the evidence is clear that there is no threat; or they may claim that the evidence is unclear and that therefore we should take no action. The former have at least the advantage that their position is rational, though it is flatly contradicted by the evidence. The later have neither the advantages of evidential support nor a rational position.
  37. Eric the Red at 01:13 AM on 22 June 2011
    How would a Solar Grand Minimum affect global warming?
    Tom, KR, Albatross, The 97 / 100 thread seems to have gone dead.
    Response:

    [DB] There are no dead or closed thread posts here at Skeptical Science, just some with no current participation.

  38. Eric the Red at 01:11 AM on 22 June 2011
    How would a Solar Grand Minimum affect global warming?
    The discussion on RC has linked to some earlier papers whcih described the potential for a solar minimum. http://www.schulphysik.de/klima/landscheidt/iceage.htm http://sesfoundation.org/dalton_minimum.pdf
  39. Australia’s contribution matters: why we can’t ignore our climate responsibilities
    "The view that one country’s actions have no effect on other countries is present in all but the largest countries, " Ridiculously, even here in the USA, it's "it won't matter because of India and China"...
  40. Linking Extreme Weather and Global Warming
    JMurphy and Tom Curtis, The Munch Re have their 2010 report available online. You can download it here. From the report: "We need look no further than this past year for evidence showing that climate change is real and continuing. The year 2010 sets the trend towards ever warmer years and an ever decreasing ice cover in the Arctic Ocean. Globally it was one of the warmest years since records began 130 years ago. The ice cover during the annual minimum in September was the third-lowest, reaching an absolute minimum for the month of June. Data collected by Munich Re also show that (after 2007) 2010 brought the second highest number of loss related weather catastrophes since 1980, when our data series began."
  41. Linking Extreme Weather and Global Warming
    Tom @116, I have to agree with Actually Thoughtful @126. Great post, sad that its contents and message are lost on some.
  42. How would a Solar Grand Minimum affect global warming?
    RealCimate has a post on the kerfuffel surrounding the statements made during the meeting of the Solar Physics Division. It is still not clear what Ken is trying to get at, other than perhaps to fabricate debate and muddy the waters. The post is about the ludicrous claims that the denialosphere (including some media outlets) and "skeptic" spin machine have made concerning the possibility that the sun could enter a Maunder-like minimum around 2020. It also presents the findings of research undertaken to address just such a question/scenario. Does Ken think that should the sun enter a Maunder-like minimum that we will enter a period of global cooling or another Little Ice age? If he broadly accepts the paper's findings then we are all mostly in agreement, his arguments are largely moot. If he disagrees, then he seems to be of the opinion that we are in for a period of prolonged global cooling. Or it might be something in between, in which case I look forward to his paper quantifying how much he thinks a Maunder-like minimum might affect global temperatures. Which is it? Because this bickering and pontificating and arguing in circles is getting very annoying. I might suggest Ken goes and tries to argue his points with the authors at RealClimate.
  43. How would a Solar Grand Minimum affect global warming?
    Ken Lambert @75, given that you now show every evidence of understanding the difference in uncertainty for absolute measurements of TSI and for relative TSI (ie, change of TSI with time), I am now at a complete loss to explain why you should quote the irrelevant uncertainty for absolute measurements rather than the directly relevant uncertainties for relative TSI when attempting to rebut KR #62.
  44. Linking Extreme Weather and Global Warming
    More information (from Oxfam) on 'extreme weather events', going back to 1980 : There is a statistically significant increase in all disasters, and this trend is driven mainly by a rising number of floods in all regions and by more storm events in Asia and the Americas. Changes in population do not fully explain the rising number of floods, nor can the trend be entirely attributed to changes in how disasters are recorded. It was not possible to directly analyse the effect of climate change on disaster trends; however, there is insufficient evidence to exclude the possibility that climate change is increasing hazards and hence trends in reported disasters. This effect is unlikely to be very large, because the magnitude of climate change over the past 20-30 years is relatively small when compared with (for example) the growth in the world’s population over that time. Trends in the number of reported natural disasters
  45. Bob Lacatena at 23:47 PM on 21 June 2011
    Infographic: 97 out of 100 climate experts think humans are causing global warming
    203, Eric the Red,
    There are clusters of values depending on the method used; models tend to yield higher values, temperature data lower, etc., resulting in several peaks within the distribution.
    I don't see this statement to be at all true, and I'm afraid I must challenge its veracity. Can you back it up by listing the studies that you believe find a most likely value for climate sensitivity of less than two, versus those greater than two? This sort of anecdotal contention, which is so at odds with everything that I myself have read, requires supporting evidence.
  46. Bob Lacatena at 23:41 PM on 21 June 2011
    Infographic: 97 out of 100 climate experts think humans are causing global warming
    203, Eric the Red,
    Risk management may be fine for politicians and insurance agents, but is fruitless in scientific work.
    I think that this is the biggest point of contention for me. We're not talking about cold, pure science. We're not trying to discover the double helix, or riddle out quantum theory in a purely abstract detached-search-for-knowledge sense. Your (as in you, personally) understandings and decisions are going to affect the course of civilization. This is not abstract. This is not trivial. This is, in every sense of the word, risk management. It is one thing to arrive at a logically consistent conclusion that there is no risk. It is another to irrationally and arbitrarily minimize that risk, dismissing it as inconvenient. You be the judge of where you lie in that spectrum, but the mere fact that you don't even choose to recognize it as a risk management issue speaks volumes.
  47. CO2 Currently Rising Faster Than The PETM Extinction Event
    Jerry #63 - excellent comment, well worth reading thoroughly. Seeing as modern civilisation could be described as 'well adapted' to current conditions, and more critically, can be described as 'tightly tied' to current conditions, in terms of the locations of global agriculture, coastal cities etc. We don't have the luxury of the camels or primates of Jerry's example, where we can simply migrate ourselves and all our infrastructure and agricultural zones to somewhere more pleasant. Regrettably maybe we're more like the plesiodapids, except that perhaps we can do something about the CO2 emissions?
  48. Australia’s contribution matters: why we can’t ignore our climate responsibilities
    Quoting from the works of Ross Garnaut can be fraught with exaggeration and flawed logic: "Since it is not possible for Australia to be a leader in reducing greenhouse gas emissions because others are already too far ahead, we should do our fair share in what the world needs to do. Let us look forward to a future in which Australia is doing its fair share in a global effort" Who are the leaders in reducing Greenhouse gases in the world? France? with 80% nuclear power? Certainly not the major emitters - China, USA nor Europe! China is adding 10 times Australia's total coal fired electricity capacity over the next 10 years. In 2020 China will have 28 times Australa's total coal fired capacity - so a drop of 5% in Australia's emissions will be insignificant. The USA has no plan for a carbon tax or emissions trading scheme and none will be passed in the forseeable future. That accounts for the two countries with 40+% of the planet's carbon emissions. Now I know Australia is renowned for punching above its weight - but we are completely deluded if we export carbon emissions offshore in a vain attempt to have an effect on the rest of the planet. Our main natural advantages are cheap energy from coal, efficient agriculture via energy intensive cultivation, export of natural gas etc, and digging up red dirt. Kill off these industries with a unilateral carbon tax and face a popular revolt over the sharp drop in living standards from loss of our main exports.
  49. CO2 Currently Rising Faster Than The PETM Extinction Event
    Regarding the above points, Abundant evidence suggests that a massive input of CO2 occurred during the onset of the PETM (this could include oxidation of CH4). There were no mass extinctions (except in many benthic foraminifera). HOWEVER, There were profound changes in the environment during the event. One only has to look at the sedimentary record. The PETM now has been clearly documented in about 150 locations from around the world (McInerney and Wing, Ann. Rev. Earth Sci., 2011, nicely show most of them on a map). At almost all these locations, the PETM is marked by an anomalous horizon. The lithological changes across the PETM relate to several factors. For example, in the deep-sea (>2000 m paleo-water depth), there is typically a drop in carbonate content caused by carbonate dissolution (aka ocean acidification). In several shallow marine sections, there is a black organic-rich shale, probably caused by enhanced runoff and water column stratification. There were also numerous prominent changes in biota. Indeed, this is why there exists an epoch boundary (i.e., the Paleocene/Eocene boundary) at the start of the event! Fro example, in Wyoming, the mammal fossils found before the event are completely different than the mammal fossils after the event. We don't really think of this as a mass extinction, though, because the number of orders does not drop precipitously. Instead, it is a wholesale migration (or perhaps even origination) of animals. So "fared well" depends on what you mean. Certainly, if you were a Plesiodapid living in Wyoming, the world was not a kind place; on the other hand, if you were a camel or a primate living somewhere unknown, Wyoming suddenly became the land of bounty. In any case, Rob's main point is entirely valid. In the last 65 million years, the PETM was by the most extreme short-term event associated with rapid warming and massive carbon input. It was marked by profound environmental changes. All indications are that carbon inputs are changing significantly faster at present-day than during the PETM. This has been spun in two different ways by many people: we're heading for catastrophe; things will be okay as Earth has been through this before. I'll just stick to the facts on this point, but note that, to suggest that changes will be minimal, is not consistent with the geological record. Jerry
  50. How would a Solar Grand Minimum affect global warming?
    Tom Curtis #72 Satellites are gererally thought to have high precision but low absolute accuracy. They can give good day to day, months to month or year to year variations - but not good absolute values. If the TSI from SORCE was an accurate absolute value then Dr Trenberth's energy balance diagram would need to be adjusted. The Incoming Solar Radiation would drop from 341W/sq.m to 340W/sq.m which would require re-adjustment of the outgoing longwave and reflection terms to give a +0.9W/sq.m warming imbalance. The SORCE people had a go at this re-balance here: http://lasp.colorado.edu/sorce/instruments/tim/tim_science.htm Whatever you can make of this Tom - it had Dr Trenberth rather puzzled.

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