Recent Comments
Prev 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 Next
Comments 85101 to 85150:
-
Charlie A at 02:49 AM on 23 May 2011Roy Spencer’s Latest Silver Bullet
What is the source for "Hansen's forcing data" in Figure 1? The link you give in two places above is the GISS-E forcing data 1880-2003 -- the set that zeros out the rate of change in black carbon and aerosols as of 1990, as can be seen in the file that includes details. Figure 1, however, shows forcing up through 2010. Is this the set from the draft Hansen et al 2011, that assumes net aerosol forcing for all years after 1990 will simply be -0.5 times the well mixed GHG forcing? Do you have a link for the forcing set used in the the graph? Thanks in advance -
RW1 at 02:30 AM on 23 May 2011Climate sensitivity is low
Riccardo (RE: 231), "RW1 modtrans does take into account emission; infact, you can see light coming from the saturated bands. On the contrary, transmittance measurements or calculations don't." OK, show me where or how it does this. Is it your contention that the reduction in transmittance from 2xCO2 is 7.4 W/m^2? -
Riccardo at 02:01 AM on 23 May 2011Climate sensitivity is low
RW1 modtrans does take into account emission; infact, you can see light coming from the saturated bands. On the contrary, transmittance measurements or calculations don't. -
WheelsOC at 01:42 AM on 23 May 2011Roy Spencer’s Latest Silver Bullet
I agree with Bickmore, lack of self-criticism seems to be a huge issue here. It was present just as strongly when Spencer concluded in his book that, "[e]ither I am smarter than the rest of the world’s climate scientists–which seems unlikely–or there are other scientists who also have evidence that global warming could be mostly natural, but have been hiding it." Being wrong never seemed to occur to him then, and it doesn't seem seriously considered now when he's still playing around with models in a seemingly blind, groping way. He should perhaps take his own advice from this tract on climate models: This is why validating the predictions of any theory is so important to the progress of science. The best test of a theory is to see whether the predictions of that theory end up being correct. In fitting his model to 20th/21st century data about OHC, he also seems to run aground on his own criticism of modelling again: The modelers will claim that their models can explain the major changes in global average temperatures over the 20th Century. While there is some truth to that, it is (1) not likely that theirs is a unique explanation, and (2) this is not an actual prediction since the answer (the actual temperature measurements) were known beforehand. If instead the modelers were NOT allowed to see the temperature changes over the 20th Century, and then were asked to produce a ‘hindcast’ of global temperatures, then this would have been a valid prediction. But instead, years of considerable trial-and-error work has gone into getting the climate models to reproduce the 20th Century temperature history, which was already known to the modelers. Some of us would call this just as much an exercise in statistical ‘curve-fitting’ as it is ‘climate model improvement’. Unless I have that wrong, he seems to be guilty of exactly the sins he's seen in others. Why is it alright for him to adjust his model to try and match observed OHC variation, but not for climate modellers to do the same with global temperatures? Shouldn't he be working blind, from 'first principles,' and wait in real-time for his model results to match future OHC measurements before declaring his 'predictions' accurate? It seems to me that his earlier critique of modelling in general would refute his own exercises if taken seriously. -
dana1981 at 01:17 AM on 23 May 2011Shapiro et al. – a New Solar Reconstruction
Ken, your question doesn't really make sense. The Earth will be in equilibrium if the net forcing is zero. Thus the TSI value to keep it in equilibrium depends on all other forcings. -
Tom Dayton at 01:11 AM on 23 May 2011Skeptical Science Educates My Students
chris1204, how can you possibly be unconvinced by the importance of multiple converging lines of evidence in scientific decision making, if you really are as knowledgeable about science as you claim? -
grypo at 00:54 AM on 23 May 2011Skeptical Science Educates My Students
Well, any digging into the issues Ken L outlined (besides the thermodynamic one, huh?), would entail much more then just mentioning those areas as "uncertain". As Prof Mandia pointed out, just mentioning that there is a "debate" over scientific subjects will only sow confusion without expert analysis. I don't believe the assignment is set up to do such a thing. -
Albatross at 00:53 AM on 23 May 2011Skeptical Science Educates My Students
Chris1204, A very eloquent articulation of your thoughts. With that said, please read Dr. Spencer Weart's excellent book titled The discovery of global warming"-- a fascinating read and demonstrates that many of the arguments being put forth today are merely recycled from those made in the early 20th century and before that even. The roots of the theory of AGW go way back. -
Albatross at 00:49 AM on 23 May 2011Skeptical Science Educates My Students
Really Ken !@42, You honestly believe that you comment comes across as constructive? -
chris1204 at 00:45 AM on 23 May 2011Skeptical Science Educates My Students
Tom Curtis @ 41: I'm so pleased you like Aristotle and Gould. However, you miss the point. Gould does in fact defend Ussher as a careful empiricist (ie, a man operating in a genuinely scientific spirit) using the limited tools available to him at the time. Nowhere do I propose that we should teach Aristotelian physics qua physics as understood today. However, one cannot appreciate a subject without at least a rudimentary understanding of our historical predecessors and their strengths and limitations. After all, Newton did speak of standing on the shoulders of giants. I suspect Aristotle featured in their number. My own fields (medicine generally and psychiatry specifically) remain very conscious of their historic antecedents. The Hippocratic corpus, for example, remains a fascinating source of the manifestations of disease through the ages as does the Bible (witness some powerful descriptions of depression as in the Book of Job, bipolar disorder or the madness of King Saul, and schizoaffective disorder, as in the madness of King Nebuchadnezzar). The Hippocratic corpus also describes depression or melancholia demonstrating all too clearly that it is no mere modern malady. No doubt, until the advent of calculus thanks to Newton and Leibniz, physics as understood today was greatly limited. More than anything, my comments are a response to a seemingly (perhaps unintentionally) derisory dismissal of a philosopher whose thinking remains pivotal to this day. The cursory treatment afforded to the philosophy of science in all too many university courses highlights the tragic schism between the exact sciences (ie, knowledge that can readily be quantified) and the humanities (knowledge that is less readily quantified) which in times gone by were both known as sciences [scientia]. Yet, without a philosophy of science, we cannot approach a subject such as global warming. Underpinning the debates are fundamental questions related to what kind of world do we want to live in, what priority do we give to competing goods, what levels of evidence do we accept, how much uncertainty do we allow, and the like. To give but one simple example, I have never been convinced by John's notion of "multiple converging lines of evidence," which I see as epistemologically problematic (much as I admire the integrity and passion that all too clearly drive his efforts). My "quarrel" (perhaps too strong a word) with this line of argument does not prevent me from believing that we quite likely live in a warming world to which human activity has made a substantial and potentially quite damaging contribution. However, our response to this undoubted risk must encompass the reality that humankind will ultimately exercise its right to respond as it sees fit for better or for worse. -
RW1 at 00:33 AM on 23 May 2011Climate sensitivity is low
Riccardo (RE: 229), "You should not expect the transmittance to saturate at 0.5" I don't. The point is if the half up/half down effect was included in the spectral data and Modtran simulation output, the maximum transmittance would be 0.5 since even if absorption is 100% half escapes to space anyway. That transmittance in the saturated lines is 1.0 means it represents the total absorption - not the downward emitted half. -
Ken Lambert at 23:34 PM on 22 May 2011Skeptical Science Educates My Students
ProfMandia #38 You should teach your students to be aware of the wide uncertainties involved in climate science. You could also point out that the oceans are not quite following the AGW script. You could also illustrate that the first law applies to climate science as much as any area of thermodynamics. You could point to Hansen's latest paper which claims the startling point that Aerosols are providing much more cooling forcing than previously assumed - which illustrates the wide error bars on this large unknown. You could refer to Trenberth's paper of 'travesty' fame to show that energy and sea level budgets are far from closed with current measurement technologies and spatial coverage. And finaly you could say that there is a vast array of misinformation on the 'denier' side of the argument, and a vast amount of exaggeration and hubris on the AGW advocacy side as well. -
jonicol at 23:26 PM on 22 May 2011Carter Confusion #1: Anthropogenic Warming
I am very interested in the range of comments on this article, none of which makes any substantial comment on the science of global warming by carbon dioxide. I am personally interested in the "science of atmospheric carbon dioxide", to use a very broad description of the total physics and spectroscopy of that gas. I want to understand the characteristics of its absorption in various molecular bands and the physical processes involved in the redistribution of that energy through intermolecular collisions and subsequent convection upwards of that energy. ( -Snip- ) In these few paragraphs I have tried to give some overview of my assessment of the scientific case for carbon dioxide’s role in global warming. I know that some of the things I have remarked upon will be controversial in this forum as they should be any where that science is being discussed. I look forward to the strong rebuttals which I expect will follow in these pages and to which I would like to heve the opportunity again to respond in due course. It would be an exciting prospect that we might actually debate some basic science in this way, with respect and due acknowledgement of each others capacity to respond and that their views, however different from their own might have at least some truth in them. John NicolResponse:[DB] This thread is about Carter's confusions about the science of global warming. As such, the vast majority of your very long comment was off-topic here on this thread. You are welcome to repost your comment on a more appropriate thread than this one (use the Search function thingy). Thanks!
-
Tom Curtis at 23:22 PM on 22 May 2011Skeptical Science Educates My Students
Marcus @36, a very nice summation. chris 1204 @37, anybody undertaking to teach others should be very clear what they intend to teach. If you want to teach physical theories then that is what you should teach, and there is no need to venture into the history of science to teach them. If you wish to teach the theories properly you should also include some of the epistemology of science, but taken only from the best examples. As such Aristotle does not rate a mention because his epistemology of science was bad, and a shackle of science for the better part of two thousand years. Even in biology, where Aristotle was at his best, you learn more from Linnaeus than from Aristotle so including discussion of Aristotle for anything but side reading is a waste of valuable instructional time. Certainly if you were to explicitly teach the history or sociology of science, Aristotle then rates a major mention, and perhaps a quarter of a lecture should be devoted to him (and the rest of the pre-moderns covered in the rest of the lecture). However if you are teaching explicitly the epistemology of science, then Aristotle rates barely a sentence, with time far better devoted to Bacon and Galileo. The simple fact is, all of Aristotle's physical theories are false. Further, his epistemology of science was bad, and anybody who follows it is likely to produce false theories. Gould's defence of Ussher is a perfect illustration (thankyou). Gould defends Ussher as being a careful scholar in an accepted scholarly tradition of his age. Well, Aristotle was not just careful, but brilliant - certainly far the superior of Plato (which is no mean feat). But Gould rightly does not defend Ussher's method as science, for it was not. Anybody who teaches Ussher's determination of the age of the Earth in a geology class is wasting their student's time. And the same is true of Aristotle. Aristotle's epistemology precluded the possibility of genuine science, and so his theories and methods have no place in the science class. I would, of course, make an exception for his teaching of logic; but even that has been superseded by boolean logic and its successors; and by probability theory. -
Ken Lambert at 23:12 PM on 22 May 2011Shapiro et al. – a New Solar Reconstruction
dana #1981 Would you venture a guess at the TSI value which would keep the Earth in equilibrium - neither gaining or losing heat? Assume we are in pre-industrial times with a CO2 concentration of about 280ppmv. -
Alexandre at 22:33 PM on 22 May 2011Skeptical Science Educates My Students
I suppose "skeptics" here would suggest it would be more productive in the quest for the Truth if students were always presented "both sides"of an issue. Man on the moon: "official sources claim American astronauts have set foot on the moon in the late 60s and early 70s. This is disputed by this and this book, and that website, though." HIV and AIDS: "mainstream science insists the HIV virus causes AIDS, and therefore you should use condoms. However, it must be stressed that condom sales are a source of revenue to large corporations. Moreover, this and this scientist claim that it's all a big hoax, and present their case in very technical and impressive terms." -
Marcus at 22:27 PM on 22 May 2011Skeptical Science Educates My Students
Again, Chris1204, you're offering up a Straw-man argument. Where, here, has anyone said that teaching of Aristotle & Plato don't have their place? Their role in the history of science is one thing, but to suggest that their actual *hypotheses* should be given equal weight to modern theories which have been proven through direct observation-then determine which is valid on the basis of a *debate* & a *vote* would cause science to degenerate into nothing more than a farce-which is exactly what the Denial Crowd actually want. -
ProfMandia at 22:11 PM on 22 May 2011Skeptical Science Educates My Students
One should never debate "science" in front of a group that does not have a rigorous scientific background in that specific discipline. Debate is a sport and the winner is the person who looks best even if he is delivering complete nonsense. Why do you suppose that people like Lindzen, Monckton, Pat Michaels, and groups such as Heartland Institute ask for debates? Is it because they have the science right or is it that they wish to "keep the controversy alive"? -
chris1204 at 22:10 PM on 22 May 2011Skeptical Science Educates My Students
Bern @ #35: Perhaps in a class looking at the history of physics, though. My point exactly. We so often teach science without any understanding of how and why scientific insights evolved at particular times in particular places whilst failing to get traction elsewhere. Whole books have been devoted to precisely this issue in relation to global warming including, of course, John’s recent scholarly efforts. For a fascinating glimpse of one aspect of the history of science, one can do little better than to glance through the works of the late Stephen Jay Gould who provides inter alia a spirited defence of Archbishop James Ussher and his now much derided chronology of the history of the creation of the world to which the leading scientists of the time, Sir Isaac Newton and Johannes Kepler, both subscribed. If you're interested, see Fall in the House of Ussher” for Gould's complete essay from "Eight Little Piggies." Awareness of the history of science in all its (to us) stranger permutations is essential if we are to approach the today’s scientific challenges with due humility thus striving to generate more light and less heat. Otherwise, we fail to appreciate the challenges facing our forebears in scientific endeavour whilst ignoring our own blindness. -
Marcus at 21:42 PM on 22 May 2011Skeptical Science Educates My Students
As Bern points out, chris1204, you're putting up a flimsy straw-man argument here. No-one here has suggested that we don't learn about the role which Plato or Aristotle played in the history of science. What we're saying is that, when you're teaching kids about a theory like-say-the one relating to the motion of planetary bodies, you don't offer them the Heliocentric theory & a Terra-centric theory & get the students to determine which is the correct theory one based on a series of debates. Yet this was what H Pierce was effectively suggesting by insisting that ProfMandia provide students with this website (which is based on hard science) & a website which is nothing more than a load of pseudo-science & politically motivated propaganda, & get students to determine which is valid-*not* on the basis of the science, but on the basis of whose better at debating. Pierce then tops it off by claiming ProfMandia is "dishonest" for not engaging in such Polemical nonsense. -
Bern at 20:42 PM on 22 May 2011Skeptical Science Educates My Students
chris1204: I think the point Tom Curtis is making, is that while it is important that students learn *about* Aristotle and similar contributors to the early bodies of science, you wouldn't want to teach some of Aristotle's now-discredited hypotheses as to how the physical universe works. At least, not in a standard physics class, where you're trying to educate students as to how the world actually works, to the best of our current scientific knowledge. Perhaps in a class looking at the history of physics, though. -
chris1204 at 20:34 PM on 22 May 2011Skeptical Science Educates My Students
Tom Curtis @ 33: So nothing taught today in science classes is based on a priori considerations? I'm sure Aristotle as a true philosopher or lover of knowledge would be utterly delighted to see his physics overturned by Newton, Einstein, and the proponents of quantum physics. The scientist who is ignorant of Aristotle and his contributions is a scientist impoverished. The Aristotelean corpus above all trains the student in the analysis of argument and an assessment of internal and external consistency. The student need not explicitly affirm his or her dependence on Aristotelian antecedents so long as s/he knows how to use them well. Understanding logic as opposed to rhetoric lie at the core of the scientific method. -
Tom Curtis at 20:02 PM on 22 May 2011Skeptical Science Educates My Students
chris 1204 @30, you don't need to teach a double major in philosophy who Plato and Aristotle are. But nor do you need to teach me that Aristotle's physics was based primarily on a priori considerations, and that it has been definitively refuted by experimentation since Galileo's experiments. Aristotle, therefore, has no place in the physics class room, unless, of course, your purpose is not to teach science but to sow confusion. Likewise, Creationism has had no place in the class room since the 19th century; and AGW denialism has had no place since about 2000. (Some AGW denialist theories have never had a place, because they are out right contradictory, or simply pseudo-scientific.) I would add that no self-reflective scientist would want their theories taught in the class room until they have taught a majority of their peers of the validity of those theories. Those peers are experts in the most important sense of the word, they know how to avoid all the basic mistakes in the subject. Therefore, if they are not persuaded, it is probably because of a genuine mistake in the novel theory. In contrast, it is patently obvious that children, even teenagers do not have the mental tools to objectively assess complex theories. Even undergraduates are normally just developing those tools, and an undergraduate course will not be able to provide even a significant fraction of the relevant information. Clearly high school students and undergraduates are non-expert in the most important meaning of that term. They are likely to make fundamental errors, and therefore to be easily persuaded to make those errors if confronted with false theories in the class room. Any scientist who wants to persuade children where they cannot persuade their peers is seeking all the rhetorical advantages of indoctrination over honest persuasion. -
Tom Curtis at 19:36 PM on 22 May 2011Skeptical Science Educates My Students
Dikran Marsupial @31, the worst feature of debates is that time is allocated, in a debate, equally between both parties. In journals, in contrast, space is allocated in proportion to the evidence that can be adduced in favour of a position. That is why denier view points are almost entirely absent from journals, but every where purveyed in public "debates". -
Dikran Marsupial at 19:30 PM on 22 May 2011Skeptical Science Educates My Students
Stephen Baines@28 You are absolutely right, a debate would be a very poor way to resolve a scientific issue, and science discovered that a long time ago (which is why science is now pushed forward via journals rather than public debates). The reason why it is a bad idea is that debates are won by rhetoric and oratory, not necessarily by truth. Debate favours the quick-witted, rather than the deep-thinker. Science needs deep thinkers more than it needs a ready wit (although some have both). Organising such a debate in a science lesson may be enjoyable for the students, but would be profoundly counter-productive if the aim was to give the students an idea of what science is about. It is a search for the truth, it isn't about "winning". -
chris1204 at 18:44 PM on 22 May 2011Skeptical Science Educates My Students
Tom Curtis @ 25: It's a shame your teachers didn't mention Aristotle who together withPlato remains the bedrock of philosophy and especially logic and without whose contributions much of modern science would very likely not have emerged. Of course, Aristotle’s thinking was limited by the primitive state of scientific knowledge of his day. Significantly, Sir Isaac Newton for all his insights into modern physic had his own raft of odd idea (at least by the standards of today). It would be fascinating to see what our descendants might make of some of our more treasured notions a mere two hundred years from today. -
JMurphy at 18:40 PM on 22 May 2011Skeptical Science Educates My Students
I'm amazed that anyone can seriously believe that a debate can determine the validity of any science. That is the sign of someone who knows the science is against them, so wants to be able to rely on debating skills - knowing, particularly, that those who work in the sciences are hardly the best at communicating and/or debating against ideological polemicists. Presumably, if h pierce had his way, there would be a debate and vote on Evolution in America, thereby leading to its dismissal and replacement in education establishments (if opinion polls are true) by some form of Creationism. -
Riccardo at 17:48 PM on 22 May 2011Wakening the Kraken
These are the weapons of the Kraken ... -
Riccardo at 16:48 PM on 22 May 2011Climate sensitivity is low
RW1 immagine a light source and a absorbing medium. A transmission experiment will give you the fraction of light passing through the medium along the line connecting the source and the detector. On the contrary, the light eventually re-emitted by the medium has no preferential directions. You should not expect the transmittance to saturate at 0.5. -
RW1 at 16:02 PM on 22 May 2011Climate sensitivity is low
Here is the composite absorption with the emitted energy spectrum (grey line), which gives 255K. You can see that where the wavelengths are completely saturated (i.e. the 15u band of CO2), the transmittance is zero. If the halving effect was included, the maximum for the saturated bands would be only 0.5 and not zero: Click -
RW1 at 15:45 PM on 22 May 2011Climate sensitivity is low
Here is another showing which gases are most responsible for absorption at various wavelengths: Click -
RW1 at 15:36 PM on 22 May 2011Climate sensitivity is low
A brief follow up: I've spent quite a bit of time emailing around the climate science community on this. None of the scientists I've communicated with seem to know much about it, and appear to have more or less just accepted the number with little (if any) thought. I'm still pursuing the issue with one of them in particular though. Meanwhile, GW has given me the details on the simulations he's done and I see no indication that he's incorrectly interpreting the results as claimed here. For example, this is plot of the clear sky absorption spectra he used, where each gas is represented by a different color. The Y axis is the amount of emitted surface power absorbed by the atmosphere. You can clearly see that the line by line transmittance is 1 minus the value. If the half up/half down effect was included, the maximum value would be 0.5 and not 1.0, because even if 100% is absorbed, half is emitted to space anyway: Click -
Stephen Baines at 15:22 PM on 22 May 2011Skeptical Science Educates My Students
"He could arrange a debate on AGW where the "Against Team" challenges the "For Team". After the debate, he could have the audience vote on the performance of the teams." Ive been trying to think about why this idea as formulated struck me as particularly bad. I mean, I'm all for democracy and having open debate. I think it comes down to two things. First, a debate should never be structured as "For" and "Against." The latter position is so much easier to maintain - you just have to sew doubt, while the other side must defend against every competing idea around, no matter how nutty. Sounds familiar. Second, public debates are actually very poor analogs for what happens in science. They are too defined in time, and in structure. As a consequence, their outcome hinges too much on rhetorical and dramatic skills of the debaters, the predispositions of the audience, and the terms of the debate. None of those have much to do with evidence. In science, the setup is actually quite different. A group of people work on a related set of problems for an indefinite period of time. Useful ideas survive and become part of settled science while non-useful ideas don't. Personality can play a role, but only temporarily. That's because scientists are not presenting evidence to a bunch of naives who aren't vested in whether their judgement is correct. Rather they are sharing with colleagues who often know as much or more about the evidence. That enforces a strict focus on the evidence, as artifice will be found out. If your colleagues accept an idea, it's because that idea has enough validity to be useful to them in future investigations. They are vested in making good decisions about which idea is wrong or right. I wonder how one could create something more akin to the activity of science in the classroom. -
Leland Palmer at 15:19 PM on 22 May 2011Wakening the Kraken
Here's another recent paper, which uses a state of the art atmospheric chemistry model to predict much stronger positive feedback from indirect atmospheric chemistry effects of large methane releases, than from the methane itself. They are talking about several hundred percent increases in stratospheric water vapor, for example, increased methane lifetime of roughly 100 percent for very large releases, and large increases of tropospheric ozone. The hydroxyl radical, by their modeling, decreases in the troposphere, where it is needed to oxidize methane, and increases in the stratosphere. The positive feedback factor that they calculate (eta) ranges from 1.5 for small releases, up to 2.9 for large ones. Strong atmospheric chemistry feedback to climate warming from Arctic methane emissionsHere we apply a “state of the art” atmospheric chemistry transport model to show that large emissions of CH4 would likely have an unexpectedly large impact on the chemical compositioof the atmosphere and on radiative forcing (RF). The indirect contribution to RF of additional methane emission is particularly important. It is shown that if global methane emissions were to increase by factors of 2.5 and 5.2 above current emissions, the indirect contributions to RF would be about 250% and 400%, respectively, of the RF that can be attributed to directly emitted methane alone.
It's a very important result, IMO, which could provide a bridge from mild CO2 based warming to runaway methane and atmospheric chemistry change based greenhouse heating. It's a very different atmosphere that they are talking about, with sustained methane release rates of 4 to 13 times those of today. Stratospheric water vapor and stratospheric hydroxyl radical increase, tropospheric hydroxyl radical decreases, and tropospheric ozone increases, leading to indirect warming several times that of the warming from methane itself. It's particularly worrisome because this appears to be an honest result, resulting from a fair query of a state of the art atmospheric chemistry transport model. If this work holds up, it may help explain the strong positive feedback of past apparent methane catastrophes including the Paleocene-Eocene Thermal Maximum and the End Permian mass extinction, I think. -
Leland Palmer at 15:05 PM on 22 May 2011Positive feedback means runaway warming
Here's another recent paper, which uses a state of the art atmospheric chemistry model to predict much stronger positive feedback from indirect atmospheric chemistry effects of large methane releases, than from the methane itself. They are talking about several hundred percent increases in stratospheric water vapor, for example, increased methane lifetime of roughly 100 percent for very large releases, and large increases of tropospheric ozone. The hydroxyl radical, by their modeling, decreases in the troposphere, where it is needed to oxidize methane, and increases in the stratosphere. The positive feedback factor that they calculate (eta) ranges from 1.5 for small releases, up to 2.9 for large ones. Strong atmospheric chemistry feedback to climate warming from Arctic methane emissionsHere we apply a “state of the art” atmospheric chemistry transport model to show that large emissions of CH4 would likely have an unexpectedly large impact on the chemical compositioof the atmosphere and on radiative forcing (RF). The indirect contribution to RF of additional methane emission is particularly important. It is shown that if global methane emissions were to increase by factors of 2.5 and 5.2 above current emissions, the indirect contributions to RF would be about 250% and 400%, respectively, of the RF that can be attributed to directly emitted methane alone.
It's a very important result, IMO, which could provide a bridge from mild CO2 based warming to runaway methane and atmospheric chemistry change based greenhouse heating. It's a very different atmosphere that they are talking about, with sustained methane release rates of 4 to 13 times those of today. Stratospheric water vapor and stratospheric hydroxyl radical increase, tropospheric hydroxyl radical decreases, and tropospheric ozone increases, leading to indirect warming several times that of the warming from methane itself. It's particularly worrisome because this appears to be an honest result, resulting from a fair query of a state of the art atmospheric chemistry transport model. If this work holds up, it may help explain the strong positive feedback of past apparent methane catastrophes including the Paleocene-Eocene Thermal Maximum and the End Permian mass extinction, I think. -
muoncounter at 13:26 PM on 22 May 2011Skeptical Science Educates My Students
hpierce #24: "make available to the students the sources of all points of views on the topic" Yes. Teach both sides; let the students decide. Where have we heard that before?The 'debate' and subsequent vote between 'magic' and 'physics' should be quite entertaining.
-
Albatross at 12:56 PM on 22 May 2011Skeptical Science Educates My Students
Tom @25, Excellent points. Likely lost on the confusionists though. And I second Daniel's request @ 24 for h pierce to apologize to Prof. Mandia. The contrarians have nothing and it is showing. -
sailrick at 12:02 PM on 22 May 2011New SkS graphic: the Respiration Carbon Cycle
Shouldn't the graphic include water as part of the active carbon cycle? -
Tom Curtis at 11:15 AM on 22 May 2011Skeptical Science Educates My Students
h pierce @24:An honest instructor should make available to the students the sources of all points of views on the topic, and then let them form their own conclusions and opinions.
Really? In grade 11 when my physics teacher was teaching my Newtonian laws of motion, and Newtons law of universal gravitation, not once did he bring out an Aristotelian. He did not bring out any geocentrists or flat earthers either. Did that make him dishonest? And why do you limit yourself to "both points of view"? There are at least five or six distinct theories presented by various kooks in opposition to evolution. There are about as many distinct denier theories on climate. But, revealingly, all lose any desire to criticize each other when a chance to attack climate scientists is in the offing. What you mean by an "honest instructor" is simply a person who will uncritically feed pseudo-science to their students without distinguishing it from the genuine article, taking great care, of course, to not give the students the critical skills needed to distinguish between the two. -
h pierce at 11:02 AM on 22 May 2011Skeptical Science Educates My Students
DB at 3 An honest instructor should make available to the students the sources of all points of views on the topic, and then let them form their own conclusions and opinions. He could arrange a debate on AGW where the "Against Team" challenges the "For Team". After the debate, he could have the audience vote on the performance of the teams. ( -Off-topic and inflammatory snipped- ).Response:[DB] "An honest instructor"
A truly appalling way to begin a comment. While that may be de rigueur in your usual venue of choice, the insinuation of dishonesty you make here is a violation of the Comments Policy.
An apology to Professor Mandia should be in the offing.
-
Tom Curtis at 09:49 AM on 22 May 2011Most of the last 10,000 years were warmer
Adelady @14"Why would sustained, slower, less spectacular, releases of aerosols have different physical characteristics?"
Because it is convenient for some to believe so, of course. -
Chris Colose at 09:48 AM on 22 May 2011Skeptical Science Educates My Students
apiratelooksat50, with respect: Your post #12 is backwards. Professionally, these aren't controversial subjects. Personally, they are. This is what separates a proper scientific education from teaspooning some odd sense of democratic sensibility into our youth, and letting them think that "all opinions" are equal. It's also what separates first-rate education at top research universities from second-rate education typical of elective meteorology courses at a community college. This is where Scott Mandia and his class is a strong exception, and I like that. But my textbooks in climate and atmospheric radiation never came with a disclaimer saying "this is all a theory" as some anti-science groups demanded happen to evolution texts. This isn't to say that I agree with the indoctrination of students into a particular world view; rather, a proper evaluation of the relevant physics (or in the case of evolution- the biochemistry, genetics, geological evidence, etc) will inevitably lead the student to the right answers, or in the case of real skepticism, actually learning to ask the right questions. I am of the perspective that teaching someone how something works is better than teaching them what is wrong with 50 fallacious arguments. The latter is how SkepticalScience is set up, which is fine. For some reason, when it comes to climate change and evolution, the latter is sometimes the more efficient setup for educating the casual reader. Furthermore, any real education will give the student a good perspective on the things which are well-known (like the validity of Planck's law) and those things which aren't too well-known (like the magnitude of cloud feedbacks). Teaching something like "anthropogenic global warming," which is not really a theory in itself, but a consequence of many different lines of physics, as intrinsically "controversial" is just doing an injustice to your students and the subject. People pay tuition for a reason, you know. -
Tom Curtis at 09:46 AM on 22 May 2011Most of the last 10,000 years were warmer
NikFromNYC @ 10: 1) The "very misleading" graph shows the actual temperatures as the GRIP site with the small crosses, and the anomaly relative to the GISP2 core with the higher of the two horizontal lines. This can only be misleading to those who read neither the information on the graph, nor the article, which states immediately below the graph:"The GISP2 series — the red line — appears to be identical to Easterbrook’s version. The bottom black line shows his 1855 “present”, and it intersects the red line in the same places as his chart. I’ve added a grey line based on the +1.44ºC quantum calculated from the GRIP temperature data, and two blue crosses, which show the GISP2 site temperatures inferred from adjusted GRIP data for 1855 and 2009."
It is hard to be clearer than that. Further, to be "mislead", a reader would have to also ignore the information in the graph plotting the temperature change at the GRIP site from 1855 to the present. 2) The clarity and openness with the information in the above article contrasts sharply with the practise of deniers. They either treat the temperature rise evident in the GISP2 core just prior to 1855 as the 20th century temperature rise (as does Easterbrook), or add a bar representing global temperature increase from (typically) 1905. The global temperature increase is significantly smaller than the local temperature increase, and comparing the two is inevitably misleading. Curiously, you find neither of those practises misleading, but find a clear debunking of the worst of them to be misleading because it clearly presents the relevant data. You must be using some non standard definition of "misleading" such as "shows my views on climate to be a house of cards". 3) In addition, Easterbrook's graph is is misleading because it treats a regional temperature index as a global temperature index. As just noted, regional temperatures have greater fluctuations in temperature than do global temperatures; a consequence of the fact that regional temperatures do not vary in synch. As can be seen from this graph of Holocene temperature proxies, regional temperature vary widely, but their average shows little variability:Indeed, the GISP2 record (light blue on the chart) shows more variability than most regional proxies, a fact that should be well known to any frequent commentator on climate. Even the average on this chart probably shows more variability than the true global mean temperatures because of the low number of proxies, and because the proxies in this chart have a Northern Hemisphere bias (with half the the proxies coming from the NH extratropics). As clearly indicated on the chart, 2004 temperatures are significantly above the average of even the Holocene Warm Period. Of course, it is rather difficult for you to comment on Easterbrook's misleading practise of treating a regional temperature proxy as a global record given that you do the same thing in your comment. 3) It is a bit rich you commenting on "misleading ... debunking[s]" when you claim that "If you actually match up the 1855 temperatures, as any sincere effort would require, you get exactly what skeptics claim history is like: a just as hot MWP and a hotter Roman period." As can be clearly seen from your plot, modern regional temperatures on the Northern Greenland ice cap are about as much warmer than the MWP as they are cooler than the Roman WP at that location. And honest description, then, would be that modern temperatures are hotter than the MWP at that location, though the Roman WP was hotter, at that location.
Of course, globally, both where probably warmer than the 1950's, but cooler than the last decade.
-
citizenschallenge at 09:37 AM on 22 May 2011Book reviews of Climate Change Denial
Yippy my copy showed up today. I've read through chapter 2 and am impressed. Well written! Thoughtful and I'm looking forward to digging into the next chapter's deconstructing of the five types of denial arguments. It'll come in very handy. Very nice clean formatting, enough references to keep me reading from here to eternity. Thanks for all the effort you folks put into it. -
adelady at 09:25 AM on 22 May 2011Abraham reply to Monckton
Kane. You might have time to watch an occasional video presentation. There are 3 here at Fool Me Once And this is the first of 4 items on Monckton's presentations at Potholer. -
Paul D at 09:12 AM on 22 May 2011Skeptical Science Educates My Students
apiratelooksat50 "Anytime I teach a controversial subject such as AGW or evolution.." Erm, they aren't controversial. Or rather any controversy is not universal. It maybe controversial in the US, which is rapidly losing any direction due to internal extremism, but it isn't very controversial in the UK. -
adelady at 09:12 AM on 22 May 2011Most of the last 10,000 years were warmer
Nik, aerosols "They might not have any truly discernible and certainly not modelable cause at all.." I realise your response slipped straight over to models and maths and never got back to the physics. But I'm still concerned about the physics and observable responses to aerosols. Just looking at the histories of calamitous volcanic eruptions near the equator which spread dust and all manner of gunk across the skies worldwide. We know from written records about the effects on temperatures, colder, and agriculture, ruinous, of these events. Why would sustained, slower, less spectacular, releases of aerosols have different physical characteristics? -
David Horton at 09:04 AM on 22 May 2011Roy Spencer’s Latest Silver Bullet
Whenever I read about Spencer's stuff the same simple (I think) unanswered question always comes to me instantly. If there is a "silver bullet" which will prevent increasing ghg emissions from warming the planet - why didn't it operate in the past? -
Alexandre at 07:40 AM on 22 May 2011Skeptical Science Educates My Students
Harry Seaward at 01:24 AM on 22 May, 2011 says Pirate's post begs a question: what if the student decided the skeptic argument was valid? What if a student "decided" (interesting choice of words) Beer-Lambert's Law, or Planck's Law was wrong? Well, he could be a genius, but chances are on the side of his being just a pranck trying to draw attention to himself. Anyway, if you "decide" established science is wrong, be prepared to back your assertions with very good data. Better data or better explanation of the data than the previous theory. -
NikFromNYC at 07:01 AM on 22 May 2011Most of the last 10,000 years were warmer
"if it wasn't the aerosols, how do you account for the physics of excluding them" They might not have any truly discernible and certainly not modelable cause at all if in fact climate represents a chaotic system on century time scales. And what system might be less expected to be prone to chaos than a huge land/air/ocean biosphere subject to solar output and orbital variations? The argument from ignorance of "forcings" is thus even less supportive of CO2 as the only alternative than I had thought. Forcings might not even be required if suddenly the ocean currents shift drastically to alter now heat is released or withheld by them for a century or two at a time. There's too many formal mathematical Platonists in climatology and not enough dynamicists, I suggest. It's assumed that weather is chaotic, but why not climate too? I suddenly have a hilarious vision of a watchmaker riding a bull.
Prev 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 Next