On Mon, Mar 10, 2014 at 1:52 PM, John Clark <[email protected]> wrote:
> On Sun, Mar 9, 2014 at 2:47 PM, Jesse Mazer <[email protected]> wrote: > >> >> >> That looks like a pretty crappy match to me. What the hell happened >>> 450 million years ago? And why did the CO2 start to drop 150 million years >>> ago but the temperature start to climb at the same time? >>> >> >> >I suspect you are asking these questions not because you are genuinely >> curious, and have an open-minded attitude about the possibility that >> climate scientists might have reasonable answers, but [...] >> > > OK OK, I'm closed minded, stupid, enjoy bad environments and am in general > am just a terrible human being; > I never accused you of being "stupid" or enjoying bad environments. I do think, as our previous discussion on thermodynamics on the "What are wavefunctions?" thread showed (see my last refutation of your claims on that thread at https://groups.google.com/d/msg/everything-list/hJ9bNWqoAzI/QTrL0CopHJ8J ) that you seem to have an overly high opinion of your ability to make informed judgments about scientific ideas in areas that you clearly haven't studied on a technical level, a very common trait among those who attack mainstream science (creationists, people who think vaccines cause autism, people who don't think HIV causes AIDS, etc.). > but my questions are still valid and deserve good answers > Which I gave you. > because before you initiate a policy that will impoverish the world for > many generations and kill lots and lots and lots of people > What "policies" are you talking about that would have these supposed effects? The EU has been on track in their goals of emissions reductions, already cutting them by 18% from 1990 levels, and I don't see them becoming impoverished or killing lots of their citizens, see http://ec.europa.eu/clima/news/articles/news_2013100901_en.htm > you should be at least as sure of yourself as President Bush was that > there were weapons of mass destruction in Iraq. Are you? > When there is widespread expert consensus on how "sure" we should be about a scientific matter, and I have no expertise in the matter myself, I tend to assume as a default that the scientific experts likely have good grounds for believing what they do. Of course it's possible on occasion that expert consensus can turn out to be badly wrong, but if you look at the history of science in the post-Newtonian era (pre-Newton, it's harder to say what counts as "science") this is actually very rare, and I can't think of any cases where the flaw in expert consensus was discovered by someone with no training in the subject themselves. So, given that the overwhelming majority of scientific papers discussing causes of the recent temperature rise agree that human activity is the main cause (97% of peer-reviewed papers according to the study at http://www.theguardian.com/environment/climate-consensus-97-per-cent/2013/may/16/climate-change-scienceofclimatechange) I take it as an operating assumption that this is very likely to be the objective reality. What policies we should take in response to that reality is another matter, but it's irrational to let the fact that you would rather not enact some proposed policies bias your beliefs about objective scientific matters (wishful thinking). Speaking of Bush and Iraq, given that we in the U.S. could spend over a trillion dollars on the Iraq war without bankrupting the country or leading to mass starvation (I don't think economists would say the crash of 2008 was caused in any direct way by this expenditure either), then it might be worth pointing out that it's been proposed that for about the same price (spread out over many years), the U.S. could convert to generating nearly all its power from solar: http://web.chem.ucsb.edu/~feldwinn/greenworks/Readings/solar_grand_plan.pdf > > > > > On the question of what happened 450 million years ago in the Ordovician >> period, I googled "Ordovician temperature" and found a discussion of some >> scientific research at >> http://www.skepticalscience.com/CO2-levels-during-the-late-Ordovician.htmlwhich >> suggests there are at least some viable hypotheses about how the >> temperature drop could be explained in the framework of existing climate >> models: >> > > Hypotheses that answer scientific puzzles are a dime a dozen, hypotheses > that correctly answer scientific puzzles are not. > That's exactly the sort of vague response a creationist would give to being shown there are reasonable hypotheses about their own claimed "puzzles". The point is, when you have a theory supported by a lot of evidence but some specific phenomena that fall under the theory aren't completely understood (like the causes of the "Cambrian explosion" in evolutionary history, or the evolutionary development of some organ whose fossil record is poor), if there are reasonable hypotheses about how the phenomena could be explained within the context of the theory, it's irrational to take a "guilty until proven innocent" stance where you harp on the fact that scientists aren't sure and take this to imply major doubts about the theory, ignoring all the positive evidence that supports it, and the fact that the proposed resolutions are consistent with what we already know, so that there is nothing about the "puzzle" which seems a priori inexplicable with the current theoretical framework. Also note that in this case, the claim that there is any mismatch between temperature changes and CO2 changes is itself just a "hypothesis" rather than an agreed fact that must be accounted for, since the papers I posted suggested that the solution is that more fine-grained CO2 and temperature data actually shows that there isn't a mismatch, and that the appearance of one was created by having too large a temporal separation between data points. > > > > Young determined that during the late Ordovician, rock weathering was at >> high levels while volcanic activity, which adds CO2 to the atmosphere, >> dropped. This led to CO2 levels falling below 3000 parts per million which >> was low enough to initiate glaciation - the growing of ice sheets. > > > So CO2 at 3000 parts per million will lead to worldwide glaciation but CO2 > at 380 parts per million will lead to catastrophic warming. Huh? > You're forgetting that the radiation from the Sun has changed significantly between then and now, which would affect the threshold for glaciation. The page at http://www.geologywales.co.uk/storms/hirnantian.htm says that in fact climate models can be calibrated to Ordovician conditions and they do "predict an ice threshold of between 2240 and 3920 ppm carbon dioxide" in that time period, the relevant section of the page is below: 'So yes, it appears that carbon dioxide levels did drop quite sharply for a time in the late Ordovician: indeed, it has been estimated that they fell from 5000ppm to 3000ppm or less (reference 6) as a consequence of the events described. '3000ppm of carbon dioxide still sounds high, but before jumping to conclusions popular elsewhere in the blogosphere, we still have another main driver to take into account. What about the Sun? Established nuclear models of main sequence stars indicate that it would have been 4-5% dimmer than it is today (references 5,6). Solar radiance is thought to have increased in a pretty much linear fashion by about 10% per billion years of Earth's history and the following graph charts this increase through the Phanerozoic: http://www.geologywales.co.uk/storms/solar.jpg 'What difference would 4-5% less incoming solar energy make? Global climate models, calibrated to today's conditions, predict that permanent ice can start to develop when carbon dioxide levels drop below 500 ppm (i.e. if all of Earth's icecaps melted in the future due to global warming caused by very high, say 800ppm, carbon dioxide levels, they would eventually start to reform if those levels again fell below the 500 ppm mark). Calibrating the models to the mid-Cenozoic gives a range for this "ice threshold" of 560-1120 ppm carbon dioxide, and as Royer (reference 6) notes, global climate models and energy balance models calibrated to Late Ordovician conditions, with 4-5% less solar irradience, predict an ice threshold of between 2240 and 3920 ppm carbon dioxide. So: combine a dimmer sun, a sudden drop in carbon dioxide levels to within the ice-threshold area and a large continent over the South Pole and that appears to have been sufficient to get the temperature low enough to allow glaciation to develop, as the consequence of several key climate drivers working in conjunction with one another.' > > >> >> And take a look at the temperature at zero years ago, does it look >>> colder or hotter than the average for the last 600 million years? >>> >> >> > Of course in the long term, life will be able to adapt to whatever rise >> in temperature is caused by global warming, but sufficiently fast rises may >> be too much for most species to adapt to >> > > The solutions proposed by environmentalists (close all nuclear reactors > immediately, stop using coal, drastically reduce the use of oil and gas) > will cause things to change one hell of a lot faster than anything nature > could dream up. > Environmentalists generally don't argue for an immediate drastic reduction, but rather implementing policies which will continually reduce fossil fuel use over the next few decades, and will do so by replacing much of the power with power from renewable sources like solar and wind. And I think only a pretty small fraction of environmentalists would want to "close all nuclear reactors immediately", in fact there are plenty who are in favor of expanding nuclear power use to try to combat climate change (I'd like to see more work done on developing thorium reactors: http://theweek.com/article/index/213611/could-thorium-make-nuclear-power-safe) > For example, The sea has risen about 6 inches during the last century, and > it has risen about 6 inches a century for the last 6 thousand years. > I don't think that claim reflects the mainstream view so it's probably something you've gotten from a fringe or outdated source, the page at http://www.ipcc.ch/publications_and_data/ar4/wg1/en/faq-5-1.html says: 'Global sea level rose by about 120 m during the several millennia that followed the end of the last ice age (approximately 21,000 years ago), and stabilised between 3,000 and 2,000 years ago. Sea level indicators suggest that global sea level did not change significantly from then until the late 19th century. The instrumental record of modern sea level change shows evidence for onset of sea level rise during the 19th century. Estimates for the 20th century show that global average sea level rose at a rate of about 1.7 mm yr-1.' > Not very surprising really, the sea has risen 410 feet in the last 20 > thousand years and you wouldn't expect a powerful trend like that to stop > on a dime. > According to the above it wasn't a continual "trend", rather sea levels rose a lot when the glaciers were melting, but had been stable for the last 2 or 3 thousand years. Before then there were few large cities on coasts, certainly nothing comparable in size to today. > And I think we can handle another 6 inches by 2114. > > > the rate of change over the next century is likely to exceed anything >> in mammalian history >> > > Mammalian history started about 240 million years ago so I have only one > word to respond to the above. BULLSHIT. > I think the paper uses "mammalian history" to refer to the "age of mammals", i.e. the Cenozoic Era which began after the extinction of the dinosaurs. I was also misremembering what the paper concluded slightly, what they say in the "Conclusions" section is that "Within a few decades, we can expect the rate of global temperature change to have exceeded the norm for mammalian history, even when interval length of measurement is taken into account." Exceeding the "norm" for mammalian history isn't quite the same as my own phrase "exceed anything in mammalian history", but they do conclude based on studies of past warming episodes that "When that threshold is crossed, we predict that the 2nd-order response to climate change--extinction and dramatic geographic range changes leading to very different taxonomic compositions relative to what now exists in given localities--will accelerate rapidly." Jesse -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
