Recent Comments

Prev  1820  1821  1822  1823  1824  1825  1826  1827  1828  1829  1830  1831  1832  1833  1834  1835  Next

Comments 91351 to 91400:

91351. rhjames at 15:18 PM on 23 March 2011
       Why we have a scientific consensus on climate change
       Sphaerica - I've been looking at climate change literature for the past 10 years. Where possible I get as close to original data as possible. I follow sea level, CO2 etc trends around the world. I don't take anything at face value, and I'm prepared to ask the hard questions. I've read much of the literature on this site. So, I don't just take the claims of this article at face value. I want to know the questions asked, the answers given, and who these scientists are. I've investigated this sort of detail before in surveys, with very disturbing findings. You mentioned retired engineers and physicists. Perhaps they are the ones who have time to go into detail, and make informed judgments, rather than follow the popular trend. My question remains - what were the exact questions asked of these scientists, and who were they?
91352. Daniel Bailey at 15:12 PM on 23 March 2011
       Arctic sea ice has recovered
       The melt? Or the Plunge?
91353. DSL at 15:10 PM on 23 March 2011
       Arctic sea ice has recovered
       I did - I didn't want to mention it. Too depressing.
91354. FatherTheo at 15:09 PM on 23 March 2011
       Why we have a scientific consensus on climate change
       I believe the study Dr. Stemler is citing is Expert Credibility in Climate Change by William R. L. Anderegg et al. published in the Proceedings of the National Academy of Science found here: http://www.pnas.org/content/early/2010/06/22/1003187107.abstract The scientists discussed in the study all self-identified in one way or other as accepting or rejecting the scientific consensus, for instance by signing petitions and so on.
       Moderator Response: [DB] Hot-linked URL.
91355. Bob Lacatena at 15:03 PM on 23 March 2011
       Why we have a scientific consensus on climate change
       rhymes,

       I've seen no real evidence to support this hypothesis...

       Then you haven't looked. Shame on you. This site is crawling with evidence (unless you simply refuse to see it).

       Computer models, yet to be substantiated by real data, are nothing more than interesting.

       False. 100% false. First, the computer models are more than "interesting" and have real value. But beyond this, evidence from a very wide variety of observations supports both warming and an anthropogenic cause. Claiming that you are right because you yourself are ignorant of the facts is hardly an argument.

       I know of many scientists that are yet to be convinced that anthropogenic warming is any more than unsubstantiated theory.

       Yes, but climate scientists? Or just people who are arrogant enough to think they're smart enough to be experts in any field of expertise, when they clearly are not? The world is crawling with retired physicists and engineers who will dispute global warming. I don't know why, but it's endemic. Every grumpy old man with a college degree and a career in the sciences (but not climate science) seems to want to angrily deny global warming. The fact that they do is hardly a weighty argument. Let me see, who should I trust? Thousands of climate scientists, actively working in the field, or a bunch of retired physicists and engineers who think they know better than everyone else, have little care for the future, and yet have repeatedly, over the course of the past decade, failed to substantively counter the data and logic which demonstrate the truth behind global warming?
91356. scaddenp at 14:58 PM on 23 March 2011
       Why we have a scientific consensus on climate change
       D'aleo AND icecap. Really. Now, any point on that "challenge" not already debunked here? Why do you go such sources when you can easily see the content is rubbish? A real challenge to consensus science would be in the form of peer-reviewed publication.
91357. Bob Lacatena at 14:56 PM on 23 March 2011
       Why we have a scientific consensus on climate change
       Norman, What is your challenge? The documents you provide are primarily just a litany of the same old, tired and false skeptic arguments, all of which are easily debunked in various parts of this site. There's little point to even looking at them. But more importantly, I couldn't find a single reference to refute the 97% consensus argument. What exactly is your point? That you are right, and your documents prove it, therefore 97% of climate scientists couldn't possibly agree with you? Personally, I think your post amounts to nothing more than off-topic trolling and should be deleted.
91358. rhjames at 14:51 PM on 23 March 2011
       Why we have a scientific consensus on climate change
       I'd like to know the question that was asked of these scientists. I'm a scientist (not involved in climate), and if I'm asked if I believe humans influence the climate, my answer is yes. If I'm asked if the net result is warming or cooling, my answer is "I don't know". If I'm asked if I believe that human activity will cause catastrophic (or even significant)warming in the next 100 years, my answer is that I've seen no real evidence to support this hypothesis. Computer models, yet to be substantiated by real data, are nothing more than interesting. My point is that scientists are trained to be very exacting. The question has to be very specific. So show me the actual questions that were asked. I know of many scientists that are yet to be convinced that anthropogenic warming is any more than unsubstantiated theory.
91359. Norman at 14:41 PM on 23 March 2011
       Why we have a scientific consensus on climate change
       Here is a challenge to the consensus argument. Plenty of graphs and data that show things may not be as certain as the 97% claim. Part One. Part Two.
       Moderator Response:

       [DB] To get a proper perspective, you should read this.

91360. KR at 14:40 PM on 23 March 2011
       2nd law of thermodynamics contradicts greenhouse theory
       Sorry to break this into multiple posts - it's late and I'm tired. L.J. Ryan - Incoming energy is set by spectral absorptivity, albedo, and the spectra of the sun in visible light. Greenhouse gases have little effect on that - the most important elements there are ozone absorption and Rayleigh scattering. Given a fixed input energy, the black body temperature represents a minimum temperature for the radiating gray body, the Earth. Any lowering of emissivity (such as increasing greenhouse gases) must be balanced by an increase in temperature above that of the black body case to match input power.
91361. dana1981 at 14:37 PM on 23 March 2011
       Pre-1940 Warming Causes and Logic
       HR - I agree climate sensitivity is what matters. But that's not the issue here.
91362. KR at 14:31 PM on 23 March 2011
       2nd law of thermodynamics contradicts greenhouse theory
       L.J. Ryan - From your reference: "That a perfectly absorptive ("black") body rises to a temperature a bit higher than an actual black body that’s free to radiate to its surroundings. A theoretical blackbody thereby defines the upper limit of temperature vs radiant absorption." And there is the error. The Earth is not a black body, but is a "gray body" with ~60% the emissive efficiency of a black body. And hence a higher temperature than a perfectly efficient black body radiator. Your reference is in quite serious error to argue against the greenhouse effect in these terms - it's a rather horrid miscasting of the situation. It's only an upper limit for a black body - anything with a lower emissivity will by necessity have a higher temperature for the same power output. I would not trust that source, given the example you presented.
91363. KR at 14:22 PM on 23 March 2011
       2nd law of thermodynamics contradicts greenhouse theory
       L.J. Ryan - Blackbody temperature is important as a theoretic limit. However, the Earth in the real universe is not a blackbody. The Stefan-Boltzmann relationship holds for the Earth, and the power radiated to space (which must match power coming in for dynamic equilibrium) is determined by both the temperature and the emissivity of the planet. Any body that is not a blackbody (with an emissivity < 1.0) must have a higher temperature to radiate the same power as that blackbody. The blackbody is the theoretic best case; everything else is less efficient. With an effective (surface to space) emissivity of 0.612, including clouds, GHG's, tropospheric effects, lapse rates, etc., a surface temp of ~287 radiates ~239 W/m^2 to space, almost equal to the sunlight coming in. The difference of 0.9 W/m^2 is the forcing, heating the climate and moving back towards dynamic equilibrium. So - you are incorrect because the Earth is not a blackbody. It has a limited emissivity to space, and the resulting temperature needed to radiate 240 W/m^2 is around 14-15C.
91364. muoncounter at 14:22 PM on 23 March 2011
       Arctic sea ice has recovered
       Anybody notice Arctic sea ice extent topping out for the winter season? -- JAXA Per their text file, the maximum extent was March 8. The Melt begins ...
91365. Philippe Chantreau at 14:16 PM on 23 March 2011
       2nd law of thermodynamics contradicts greenhouse theory
       "how does a body at 255K which is loosing heat increase it's temperature simply by slowing it's cooling....remember blackbody temperature is the theoretical maximum temp." Considering that the body in question is continuously receiving energy at a more or less constant rate, it does not seem so difficult to imagine that its temperature will increase if the rate at which it can radiate that energy is decreased. In fact, I would have a hard time to understand if it did not warm up under these conditions.
91366. Chris Colose at 14:16 PM on 23 March 2011
       Understanding Solar Evolution Pt. 1
       garythompson, A good point, but I'd stress that CO2 is a big player in past climate, and there's no reason it cannot generate a large greenhouse effect. The key suggestion that the Sagan paper made was that Ammonia was a plausible greenhouse gas that could help rectify the faint sun problem, but it was later shown that this would be photochemically unstable in the atmosphere (e.g., Kuhn and Atreya, 1979). Although they were wrong, it is a great paper that paved way for an enormous amount of research...just how science should be.
91367. L.J. Ryan at 14:14 PM on 23 March 2011
       2nd law of thermodynamics contradicts greenhouse theory
       KR, John Cook, Tom Curtis Please explain why, seriously, why Kirchhoff's cavity experiment does not represent the theoretical BB maximum temp. I realize it doesn't explain the 33K delta but why is wrong? Maybe your superior physics can explain how BB maximums should be determined. Don't insult me or say I'm wrong without explanation of what is wrong.
91368. garythompson at 13:58 PM on 23 March 2011
       Understanding Solar Evolution Pt. 1
       I just read that Sagan paper that was referenced in your first paragraph. There was an interesting portion that I'll quote here: "Major variation in the CO2 abundance will have only minor greenhouse effects because the strongest bands are nearly saturated. A change in the present CO2 abundance by a factor of 2 will produce directly a 2C variation in surface temperature." Granted that Dr. Sagan wrote that in 1972 and there have been many improvements in our understanding of how CO2 affects the Enhanced GHE. In 1972 the CO2 atmospheric concentration as measured by Mauna Loa was 326 ppm and the CRU temp data shows we have gained 0.5C since 1972 while increasing our CO2 concentration by roughly 70ppm or 21% over the 326 ppm level. So we are about 1/5th of our way to doubling CO2 from 1972 levels and we are on track to match the prediction made in this paper that was written almost 40 years ago.
91369. KR at 13:43 PM on 23 March 2011
       2nd law of thermodynamics contradicts greenhouse theory
       L.J. Ryan - "Earths blackbody temperature is 255K. This represents the theoretical maximum attainable temperature via the suns radiation." To be succinct - Bull - a completely unsupported statement. The surface of the Earth radiates at a temperature of 14C, or 287.15K, with an overall emissivity of 0.98. Upper layers of the troposphere (due to lapse rate) radiate at much higher altitudes, colder temperatures, rendering the planetary emissivity at ~0.612, regulating the amount of energy radiated at any temperature, and driving the surface temperature to the aforementioned 14C. Please - read some physics, get a clue. --- Folks, L.J.Ryan has shown either a complete lack of physics understanding, or a deliberate set of obfuscations. None of his objections has made sense. Damorbel is (in my opinion) a complete troll - he hasn't defended a single assertion, but keeps raising red herrings whenever pinned down, as he has done for over 4 months on this thread. He is now (as others have noted) circling back to previous disproved notions from several months ago, presented as fresh to people who have joined the thread. We are being trolled - do not feed the trolls. Moderators, John Cook - I'll join with previous posters; this cycle of denial and red herrings has gone on long enough. Are there any options in this regard? Perhaps deleting postings repeating junk from months ago? For some reason this particular thread attracts people who think that they either understand thermodynamics better than the previous 150 years of physicists, or perhaps feel that deliberate obfuscation and "common sense" arguments will draw out the discussion. 16 pages, >770 posts, with every skeptic argument repeated multiple times. Gah...
       Moderator Response:

       [DB] "We are being trolled - do not feed the trolls."

       I will join you out on that limb.  Short of a comment directly violating the Comments Policy, what we can do is this: Merely repeating a previously expressed position without adding anything new is indeed grounds for moderation.  So if anyone notices a comment being lifted from a previous one without anything new being added, bring it to the Moderator's attention. 

       700+ posts is a lot; the Mods are human & can't be expected to remember each and every post.  So help each other out:

       1. DNFTT (no matter how much you want to, Do Not Engage)
       2. Be on the watch for recycled comments by those obviously clogging up the threads
       3. Let the Mods know when you see those recycled comments

       Trolls live for attention & generating controversy; deny them the pleasure.  Those that abuse the priviledge of participating in this community may lose that priviledge.

       Thanks for your time.

91370. garythompson at 13:33 PM on 23 March 2011
       Understanding Solar Evolution Pt. 1
       Great post - As an amateur astronomer (and I stress amateur), I really enjoyed this post and look forward to reading the sagan paper referenced in the first paragraph. I've read only the high level articles explaining the HR diagram, main sequence and stellar evolution but I enjoyed a more detail look at the science. For those of you, like myself, who couldn't access that link due to the pay fire wall, here is another location.
91371. scaddenp at 13:31 PM on 23 March 2011
       It's the sun
       John. Nope. Spectral signature in IR range is insignificant. We measure spectra at TOA and earth-bound and what we see is consistent with GHE, not your idea. "Our contribution to CO2 etc is nothing compared to that produced by vulcanism." This is false. See Volcanoes and global warming Global warming occurs for complex reasons ( and not that well understood by the so-called experts)and attributing it to man made pollution (alone) is nonsense. Care to support that assertion with some science? You might also like to look at Climate has changed before
91372. IanC at 13:15 PM on 23 March 2011
       CO2 has been higher in the past
       Jay Cadbury (in response to your comment from Preventing Misinformation thread) Seeing that the current fauna is very different from what you would find all those years ago, I am not sure how comparing the projected temperature and CO2 to their respective values in a such a distant past relevant. What strikes me the most is the fact that even during the wild prolonged swings seen in the Volstok ice-core data, the warming was 10 degrees per 10,000 years, or maybe about 0.05 degrees per century (assuming arctic is warming twice the rate of the global average as it currently is); this pales in comparison to the projected warming (2 degrees per century even on the low end), which is a factor of 40 difference! Whereas in the past longer living mammals have 100s of generation to adapt, now it becomes two generations or so. How can this not be significant to the entire biosphere? While humans as a whole are adaptive, I think there are two caveats 1) Adaptability comes at a price. Most studies on the economic impacts of GW concludes that it is cheaper to cut back on GHG now rather than to adapt. 2) Adaptability depends on the wealth of the country. While people in developed countries are better at adapting (we can buy food from chile if crops from mexico fails), but what will an African family do when crops fail? What will a village in indonesia do when fish stock crashes?
91373. RW1 at 13:13 PM on 23 March 2011
       2nd law of thermodynamics contradicts greenhouse theory
       damorbel (RE: 755), "And why the 'GH' effect is not a radiation effect... from... GH gases." OK, then what is the primary mechanism for the greenhouse effect? "No amount of refocussing etc., etc., of photons from a cold (255K) source, like the upper troposphere, can produce a temperature higher than 255K... anywhere. It's the photons you see, they don't have enough energy. They may have all the power (W/m^2) you can imagine* but no amount of refocussing, adding together, accummulating in reflecting cavities etc., etc. will raise their energy. Or, in other words, increase the temperature of.... anything. That is what the 2nd law is all about." Not really. The second law primarily states that heat can only flow from warm to cold - not the other way around. The atmosphere is largely transparent to the energy coming in from the Sun. The bottom line is the rate the incoming energy can leave the system from the surface is slower than the rate it is coming into the surface. The effect in principle is not much different than the interior of a car heating up inside on cold day from sitting out in the Sun. The Sun's energy is mostly transparent through the windows. It's then absorbed and re-radiated by the interior car components. The rate at which the energy is entering the interior is faster than the rate the re-radiated energy can leave the interior; therefore, the interior has to heat up. Ultimately, when the rate of energy entering something is faster than rate it can leave, the something has to heat up. That's the GHE.
91374. johng8seq at 13:07 PM on 23 March 2011
       It's the sun
       

       Going back to the original premisen that because solar radiation has reduced since 1960, the sun has nothing to do with global temperature rise - this agument is flawed. The reason being that according to Wein's Distribution Law for black body radiation, if the sun has cooled such that its total radiation has reduced, then the radiation peak will have also shifted towards the infra red. These means that the Earth is likely to receive more insolation because we know the Earth absorbs radiation in the infra red region than at higher frequencies ( shorter wavelengths )due to the greenhouse ( and other effects ). Hence the rise in global temperatures. Global warming occurs for complex reasons ( and not that well understood by the so-called experts)and attributing it to man made pollution (alone) is nonsense. It has occurred in the past and will occur again in the future. Our contribution to CO2 etc is nothing compared to that produced by vulcanism.

       Response:

       [DB] Welcome to Skeptical Science!  There is an immense amount of reference material discussed here and it can be a bit difficult at first to find an answer to your questions. 

       That's why we recommend that Newcomers, Start Here and then learn The Big Picture.

       I also recommend watching this video on why CO₂ is the biggest climate control knob in Earth's history.

       Further general questions can usually be be answered by first using the Search function in the upper left of every Skeptical Science page to see if there is already a post on it (odds are, there is).  If you still have questions, use the Search function located in the upper left of every page here at Skeptical Science and post your question on the most pertinent thread.

       Remember to frame your questions in compliance with the Comments Policy and lastly, to use the Preview function below the comment box to ensure that any html tags you're using work properly.

       With that out of the way, there is much indeed wrong with your comment, more than can be summed up by just one thread post.  Please break up your many objections into their individual parts and post them on the appropriate thread (that's where the Search function will help you).  Thanks!

91375. scaddenp at 13:01 PM on 23 March 2011
       2nd law of thermodynamics contradicts greenhouse theory
       Tedious indeed. If you got past the idea that the atmosphere is warming the planet and bothered to learn how the GHE effects, then you would get some progress. Remember nature is the atmosphere. Your version of physics doesnt account for the observed world. The textbook version does. Is that a hint?
91376. HumanityRules at 12:55 PM on 23 March 2011
       Pre-1940 Warming Causes and Logic
       55 dana1981 OK I was just thinking about what really matters, I guess we have different priorities. 1) Too much wiggle room to for this to be accurate. 2) I agree with you 3) The basic physics only tells us so much and I think is largely uncontested. It's how this is mediated by the the complex, chaotic system that differentiates trivial AGW from catastrophic AGW. The basic physics doesn't give us climate sensitivity and that seems to be what ultimately matters.
91377. muoncounter at 12:52 PM on 23 March 2011
       2nd law of thermodynamics contradicts greenhouse theory
       LJ Ryan: "regardless of re-radiation and reflection, the atmosphere can NOT warm the warmer Earth...Period." So the world you live in has an average temperature of -18C? How's that working out? Or did you forget that the blackbody 'theoretical maximum' you cling to refers to an object in equilibrium? Do you suggest that is the case for the earth? If so, do you not recall that we have an atmosphere, which traps energy that would otherwise escape? Even died-in-the-wool deniers accept that much. It is tedious to hear these repetitious 'objections' to basic physics that should be well-understood by now. Read and learn, my friend. If nothing else, the quality of your questions will improve.
91378. HumanityRules at 12:36 PM on 23 March 2011
       Pre-1940 Warming Causes and Logic
       56 IanC I guess Dana mentioning AMO in the same sentance as these papers was what I was getting at. I can't see where these papers deal with multidecadal cycles.
91379. Alex C at 12:35 PM on 23 March 2011
       Understanding Solar Evolution Pt. 1
       Great post Chris, thanks for the explanation on the topic. I had tried doing some superficial Googling on why stars increase in luminosity as they age, and the best source I could find was wikipedia's page which was actually very unspecific toward this aspect of a star's lifetime. Of course, when I say superficial, I'm talking about the hair of my chinny-chin chin superficial. I also think that quantum tunneling is a fascinating concept. I had always thought that the high internal density of our star forced fusion.
91380. HumanityRules at 12:31 PM on 23 March 2011
       Pre-1940 Warming Causes and Logic
       40 IanC There is this review which explains the background to different estimates of multi-centennial TSI variation (starting on page 11 if you don't want to read all 53 pages). It specifically states why the early Hoyt and Schatten estimates may simply be wrong based on false assumptions. It can't help with why the more recent estimates (1-2 W/M2 for MM to present) are different to the new Schrijver work, the review doesn't include the Schrijver work. The Schrijver explanation for the difference between the recent estimates and their work is described on page 4 of the PDF and is summarized in Fig3. I have to admit it get's too technical for me but the gist would seem to be thus. It would seem that TSI variation is affected by things that were visible (sunspots) and not visible (faculae??) to early observers. Modern scientist have to extrapolate back these non-visible features by modelling them. Without access to the conditions in 2008/2009 to constrain some of the parameters the use of SSN to estimate magnetic flux has introduced biases which are compounded the further one goes back in time. I think Schrijvers point is that the quiet conditions of 2008/2009 constrain some of the modelling parameters better and lead to lower estimates of TSI variation. But as I say this is all too technical for me so I could be wrong, I also have no way of judging the merit of the argument It seems highly disturbing that in your view the TSI variation can undergo maybe a ten-fold revision downward without having implications about our understanding of what drives climate. If that's the case it seems hardly worth deriving estimates in the first place, again this looks like far too much wiggle factor for this to be meaningful science. Maybe you can explain why ten-fold drops in TSI variation don't really matter? I know the line on this website is that if solar forcing is lowered then that just pushes up climate sensitivity. I see how that works with respect to the simple equation that describes the relationship between temperature change and forcing, but that's all. It's certainly not the only conclusion one could draw from that observation and can only be made by assuming a high degree of certainty about the science. The knock on effects of high climate sensitivity for other aspects of the science just seem to be ignored as well.
91381. muoncounter at 12:26 PM on 23 March 2011
       2nd law of thermodynamics contradicts greenhouse theory
       damorbel Your lecture over the distinction between watts and Joules explains nothing; if I shine a 100 watt light bulb on your lecture notes, each second requires 100 Joules of electrical energy. If that energy is constrained from leaving the immediate environment by whatever means, the environment, including your lecture, heats up. If I direct a 125 milliWatt laser pointer on the wick of a candle in the vicinity of those notes, I can quickly set them aflame. Those applications are radiation effects. Your gravitational heating was ably dismissed on a number of occasions; the most recent by Tom C. No one is buying this brand of soap today.
91382. Bern at 12:20 PM on 23 March 2011
       Zero Carbon Australia: We can do it
       Ken Lambert: if you invested your hard-earned on the basis of my back-of-the-envelope calculations, then I've got a nice bridge I'd like to sell you... :-P My point wasn't to do a detailed cost-benefit analysis, but to throw out some numbers for consideration. Yes, those numbers likely to be wildly inaccurate, but even if I was out by a factor of three, then going solar thermal has a long-term break even point, compared to coal - while totally ignoring the climate change costs associated with continuing coal use (which *will* be measured in $trillions, and in the absolute worst case, could cost 100% of world GDP - i.e. complete breakdown of global economies)
91383. L.J. Ryan at 12:20 PM on 23 March 2011
       2nd law of thermodynamics contradicts greenhouse theory
       Phil 754 "No-one believes the cold atmosphere warms the warmer earth. The Greenhouse effect slows the rate at which heat escapes from the earth. Period. " Earths blackbody temperature is 255K. This represents the theoretical maximum attainable temperature via the suns radiation. Kirchhoff's cavity experiment and subsequent law and Planks law were both derived by this pressies. So regardless of re-radiation and reflection, the atmosphere can NOT warm the warmer Earth...Period. Yet GHG proponents claim slowing the rate at which heat escapes the 255K earth some how warms the earth surface to 288K. So Phil, how does a body at 255K which is loosing heat increase it's temperature simply by slowing it's cooling....remember blackbody temperature is the theoretical maximum temp.
91384. IanC at 12:17 PM on 23 March 2011
       Pre-1940 Warming Causes and Logic
       HR, Meehl et al suggests warming due to volcano is 0.2, which makes up a significant portion of the 'other' warming. Keep in mind that the error bar for the temperature is at least 0.1 of a degrees, the difference is not as big you suggest. Regarding ocean oscillations, ENSO seems to be resolved in both the papers.
91385. adelady at 12:14 PM on 23 March 2011
       CO2 has been higher in the past
       "technology will save us"? Only if we choose, actively choose, to apply our skills appropriately. This article is just one example of approaches that some people are considering. A lot of this work, of course, is focused on how it might be applied for 'clean coal' technology. While we sit and wait for 'clean coal', there's no reason why we couldn't set up a few trial projects to quarry, mill and distribute by wind and water some of the minerals that would normally do the job on geological time scales. No matter how slow or inefficient some of those techniques are, all of them would be much, much faster than geological weathering. And when coral reefs start collapsing badly under acidification, scattering dust and gravel from such rocks into the rivers feeding into the waters around reefs might be the least worst thing we could do to hold back the speed of the damaging effects. I'm sure there will be other geo-engineering ideas (forget the sulphur) and some of them will have to be implemented when we spectacularly fail to deal with the carbon side of the geological equation.
91386. Bern at 12:02 PM on 23 March 2011
       Understanding Solar Evolution Pt. 1
       Chris, thanks for the article. I enjoyed reading it - must be at least 20 years, maybe more, since I last read any detailed explanations of stellar evolution...
91387. alan_marshall at 12:01 PM on 23 March 2011
       The Libertarian Climate Conundrum
       RSVP @ 47 Human beings are the only species with the capacity to destroy the Earth. We are also the only species with the capacity to save it, but only if we act as one. As a species, we therefore have a duty of stewardship. Dr Tim Flannery, author of “The Weather Makers”, is well known to those who follow climate science. In his latest book "Here on Earth", he has a vision of what is needed: The immediate challenge is fundamental - to manage our atmospheric and oceanic global commons - and the unavoidable cost of success in this is that nations must cede real authority, as they do whenever they agree to act in common to secure the welfare of all. This does not mean the creation of a world government, simply the enforcement of common rules, for the common good. Even if the current disorganised national efforts succeed in stabilising the concentration of CO2, it will not be enough. If we are to ever reduce atmospheric CO2 to a safe level, we need to extract the bulk of what has been emitted from 1750 up till now. That will require either carbon sequestration on an industrial scale, or geo-engineering. Both these solutions will involve decisions we make as a species, not as competing peoples. As Archbishop Desmond Tutu warned at Copenhagen, nations will "sink or swim together". That does not imply draconian control of our everyday lives. I am a believer in markets. For example, rather than ration gasoline, it is much better to price it in a way that gives people an incentive to use less, while providing compensation so that their overall standard of living is not reduced. Some of my thoughts on economic and political solutions are published at www.climatechangeanswers.org.
91388. JulianRGP at 11:55 AM on 23 March 2011
       Preventing Misinformation
       I found the article really useful, so this comment is about just one point in the article The article describes the statement "CO2 is less than a mere four 100ths of 1% [of the atmosphere]" as an error (one of the "three principle errors" - "principal" by the way). The problem with Thompson's statement is not that it's erroneous (it's equivalent to saying 400ppm if my arithmetic is correct), but that it's being misleadingly used to support an erroneous case. The error is in the inference and the remaining two statements. I am happy with the following paragraph in this article - a small quantity can have a big effect - which shows why the statement in question is being misleadingly used. I think that simply saying it's an error leaves the article open to valid criticism. Of course the word "mere" in Thompson's statement is pejorative, but could be turned around to advantage. Although the quantity of CO2 is a "mere four 100ths of 1%" of the atmosphere, we already know that a mere three 100ths of 1% is enough to stop the earth turning into a snowball.
91389. scaddenp at 11:46 AM on 23 March 2011
       Zero Carbon Australia: We can do it
       If cooling is impaired, then that limits output. No contradiction here. Efficiency losses on ramp-down arent that great. They do work much more efficiently at constant load agreed, but then you do need base-load. 80% for CCGT?? 60% is outstanding. Got a link for someone claiming 80%? I also dont believe a single cycle turbine has ever hit 60%. However, for all that defense, I think moving away from coal power is highly desirable. They are inefficient, coal is dirty industry, and we cant afford the climate cost. That is reason enough. No need to gild the argument with spurious other factors.
91390. Don Gisselbeck at 11:37 AM on 23 March 2011
       CO2 has been higher in the past
       In what way does "technology will save us" (what "we are adaptable" means) differ from "God will save us"? Both are entirely faith based and neither has a shred of evidence to support it.
91391. Marcus at 11:33 AM on 23 March 2011
       Zero Carbon Australia: We can do it
       scaddenp. During Summer, peak demand for power frequently increases, & this leads to load shedding-this is usually reported in the press as an inability for the base-load power stations to ramp up supply. "You get efficiency losses (effectively useful heat that isnt being converted) as station comes off load, but they can certainly come down (and up) fast." Yes, but the key point is the efficiency losses-this does limit its flexibility. Most renewable energy power stations can adjust their output *without* those same efficiency losses. Of course, coal power stations aren't very efficient to begin with-with only 35% of the heat from the coal being used to create steam. Personally, I think gas (be it natural gas or methane from decomposition of organic material) is much better-as even a conventional Gas Turbine gets 60% thermal efficiency-with a Combined Cycle Gas Turbine getting as much as 80%.
91392. adelady at 11:24 AM on 23 March 2011
       Those who contribute the least greenhouse gases will be most impacted by climate change
       Gilles@84. Huh? Perhaps you and I have a different definition of 'develop'. Why on earth would a poor country "develop =only= through an increase of FF consumption."? They now have options, much more developed options than we had at the same stage of development out of mainly rural communities. One of those options is to choose, really choose, to 'develop' at a rate that can be supported by renewables only. It might be slower than you or I might prefer, but it is still development. If they get it right, as their building standards upgrade, they'll be able to use solar roofing materials pre-coated, ready to plug in to business and domestic power supplies. Distributed power generation is a far better option for currently developing countries anyway for a whole heap of reasons. If the pace is slow and steady, when the accumulating wealth of the population allows a real move to individual cars for a larger middle class - there'll be a ready supply of EVs to meet that need too - and those people will be in a position to upgrade their re-charging facilities as well if they need to. There is nothing exciting or glamorous about the 19th century technology of digging stuff up to burn it to generate power. I can see no good reason why anyone would want it, apart from politicians addicted to ribbon-cutting events. Even then, I presume local mayors and the like could cook up some sort of ceremonial ritual when a few villages gather enough resources to establish a communal windfarm, if they wanted to.
91393. scaddenp at 11:18 AM on 23 March 2011
       Zero Carbon Australia: We can do it
       Well, it feels very strange going into bat for Ken, but... "Also, if Coal Power stations are *so* flexible, then why do we get constant load shedding in Summer?" I'm not entirely sure what you mean, but station efficiency and generation capacity is dependent also their ability to reject heat to cool steam. This most certainly has a seasonal influence. " Why do the plants operate at close to 100% capacity 24/7, when off-peak demand is barely *half* of that during the day? They'd hardly waste the fuel, so I'd guess its because they *can't* turn down the power to match supply." I think you need to have some pretty complete figures on demand and production. Stations most certainly CAN turn down the power to match demand. You get efficiency losses (effectively useful heat that isnt being converted) as station comes off load, but they can certainly come down (and up) fast. I'm not that familiar with overall Australian generation system, but I would expect hydro to be used when possible, BIG coal to provide base load, and "others" to balance demand. Do I know anything about coal power stations? Well I am programme leader for this project and I've looked at a live data from quite a few Australian power stations.
91394. dana1981 at 11:08 AM on 23 March 2011
       Pre-1940 Warming Causes and Logic
       HR -

       "Surely the point of the article is that you have some how accounted for the warming in this period. Is that the point?"

       This post is a rebuttal to the "skeptic" myth that the pre-1940 warming was purely natural, and as large as the current warming, thus the current warming could also be natural. The article refuted all three of these points. 1) A significant portion (close to half) of the pre-1940 warming was anthropogenic. 2) The pre-1940 warming was smaller than the current warming. 3) We know the current warming is anthropogenic based on physics. Even if the first two "skeptic" points were true, it does not follow that the current warming is natural.
91395. Marcus at 11:07 AM on 23 March 2011
       The True Cost of Coal Power
       "All the rest is totally unable to power a modern country, despite everything you can read." Yep, that's exactly what I'd expect you to say....don't believe the *facts*, says Gilles, only believe my unsubstantiated assertions. I've shown that many 1st World Countries are now producing *more* wealth with lower energy input than what they were 30 years ago (just read the IEA reports if you don't believe me), & that many of those same 1st World Countries are now sourcing more of that energy from renewable sources than 30 years ago-so that really does put the kibosh on your claims. As renewable energy technology continues to improve in price, reliability & total output, the more we'll be able to generate wealth *without* the need for fossil fuels-or nuclear power. Seriously, Gilles, I'm totally *done* with you on this matter. You clearly want to keep living in this fantasy land where nothing but fossil fuels can generate wealth-even when the facts don't support you-so I really don't see why I should continue wasting my breath!
91396. Marcus at 11:00 AM on 23 March 2011
       Zero Carbon Australia: We can do it
       "It seems that I am 'horribly' wrong all over the park Marcus. It only that were true." Yes, you *are* horribly wrong Ken-& still are-but that's what happens when you rely on Coal Industry propaganda & not actual *facts*. Do you deny the press reports about 85% of Queensland's Coal mines being partially or completely flooded? Do you honestly believe that won't have-or hasn't already-had impact on supply? Also, if Coal Power stations are *so* flexible, then why do we get constant load shedding in Summer? Why do the plants operate at close to 100% capacity 24/7, when off-peak demand is barely *half* of that during the day? They'd hardly waste the fuel, so I'd guess its because they *can't* turn down the power to match supply. As to Transmission & Distribution losses, in spite of your claims this has everything to do with *distance*-the longer the distance between energy supply & energy demand, the greater the losses in electricity along the line. Distributed Generation is the only way to reduce-or eliminate-these losses, but inflexible coal power stations don't fit into a distributed generation framework very well. I've read far & wide on Wind-Farms, & your comments continue to display your ignorance regarding them. A 3MW Wind Turbine, operating at 30% Capacity Factor, will actually generate 8,000MW-h per year. Of course, without storage, some of the excess capacity-especially at night-will either go to waste or won't be harvested (i.e., excess capacity will get shut down). This is why VRB's have proven so successful at raising Wind Farm Capacity factors-to as high as 60% to 70%. Again, from my reading, current capacity factors are between 20% to 40%, with most modern Wind-farms achieving 30%-35% (without storage)-your ignorance of these facts doesn't make them any less real. Your talk of the negative health impacts of "Infrasound" merely prove that you spend way too much time reading The Australian for your information-a well known, anti-renewable newspaper. There is absolutely *no* medical basis for this so-called "disease", & its extremely odd that no one who actually has the wind farms *on* their properties (& are thus being *paid* for the use of their land) has actually been effected by Infransound-only those who live several kilometers away & object to the view. I wonder how they'd feel living near a coal power station & its associated, open-pit coal mine? Your claims about the distance taken up by a wind farm are equally facetious. Are you going to tell me that Coal Power stations, & their associated mines, don't take up land? Yet, unlike Coal Power stations, land with wind turbines on them are still able to be used for other purposes. Lastly, though your concern for endangered birds is....touching, its not a very good reason to oppose wind farms. Modern Wind Farms actually have very little negative impact on bird populations &-in fact-its been shown that the negative environmental impacts of the mining & burning of coal do *far* more damage to bird populations (per MW-h of electricity generated) than wind turbines. You know, what with all the land degradation & the harmful emissions from the power station-as well as the looming impacts of climate change. Seriously, Ken, I think you need to read a little more widely than the brochures handed out by WMC, BHP & Rio-Tinto.
91397. johnd at 10:54 AM on 23 March 2011
       Pre-1940 Warming Causes and Logic
       Robert Way at 13:24 PM, I agree. The links provided in another post --"[DB] There is no robust evidence (AFAIK) showing that oceanic cycles affect the global land+sea temperatures, as Tamino thoroughly shows (here and here for starters)." were not very informative. The Tamino examination of the MEI only looked at 1975 onwards whilst the AMO examination went back to 1880. Firstly they should all address the same time frame, and secondly the matter cannot be properly understood or quantified by individual analysis of separate systems. The objective should be to examine the global response and so the systems from every ocean, every ocean, have to be examined in order for the nett response to be determined. It is very clear that all the systems oscillate differently, at times in concert, at other times offsetting and yet other times intensifying the effects of adjacent systems. The time spent in each phase varies as well as the magnitude, so trying to analyse just one system over less than one complete oscillation provides virtually nothing meaningful in a global sense. Has anyone produced a study that has tracked the nett total heat that is sunk or released to or from the oceans due to all such the cycles?
91398. scaddenp at 10:37 AM on 23 March 2011
       Zero Carbon Australia: We can do it
       Firstly, I dont buy that we need to go to zero. We just have reduce one hell of a lot (but then I work in oil/coal so maybe that is rationalization). Hard to see how we drop coal for steel-making. Second, I was impressed by the range of fuel options for liquid fuels detailed by cudby in from smoke to mirrors for those applications that have to have them. Will they be as cheap as FF. Nope, but then who thinks climate change will be free?
91399. les at 10:34 AM on 23 March 2011
       Those who contribute the least greenhouse gases will be most impacted by climate change
       84 Gilled I know what an envelope is mathematically. That proves exactly and identically nothing about your statements except that they are mumbo-jumbo psudo science. You say the words but don't link them to reality. I really have no idea why you bother. It fools no one. For the attention, maybe? Anyway, at least we agree that you have completely failed to backup your points I had noted above. So there, really, is an end to it.
91400. scaddenp at 10:26 AM on 23 March 2011
       Those who contribute the least greenhouse gases will be most impacted by climate change
       "Obviously poor countries can develop only through an increase of FF consumption," Here we go again. Tell us what to read to back that assertion.

Prev  1820  1821  1822  1823  1824  1825  1826  1827  1828  1829  1830  1831  1832  1833  1834  1835  Next