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quokka at 16:58 PM on 18 May 2010Species extinctions happening before our eyes
#52 nofreewind: In the abstract Eschenbach states "Very few continental birds or mammals are recorded as having gone extinct, and none have gone extinct from habitat reduction alone. No continental forest bird or mammal is recorded as having gone extinct from any cause." Having a look at the Australian government's list of extinct species, there are 27 mammals: http://www.environment.gov.au/cgi-bin/sprat/public/publicthreatenedlist.pl?wanted=fauna#mammals_extinct Among them is the Crescent Nail-tail Wallaby, which inhabited woodlands. Among the extinct birds are the Rufous Bristlebird (western), South-western Rufous Bristlebird which lived in forests. I didn't get past the abstract. There is only so much WUWT I can take in one sitting. -
PaulK at 16:04 PM on 18 May 2010There's no empirical evidence
As above but with some corrected subscript problems in this version. Riccardo #53 Thanks for the response. I don’t actually disagree with anything you have written, but I believe that you need to follow your conclusions to the next logical step. I wrote initially: “For an idealised system the OLR perturbation response to a year-on-year geometric growth in CO2 should be a monotonic decrease in OLR upto the equilibration time and a constant (negative perturbation) value thereafter.” I think that you are agreeing with this, but let me expand a little. Consider a single ANNUAL pulse of CO2 and an OLR response function in time, f(t), on (0,te), where te is the equilibration time. This function has the properties:- f(t) = 0 at t=0 f(t) <0 for all 0 is less than t is less than te, and f(t) = 0 for all t>=te. Let us define the integral of this function between 0 and t as F(t). The area subtended by the curve at t=te is the FINITE net energy received by the planet as a result of the single year pulse. Call this absolute value Ea. Or we can write F(te) = -Ea. Ea can be related to an increase in the temperature of the planet at equilibrium via the specific heat of the system. For a geometric growth model of CO2, the second year pulse yields an identical response to the first year with an energy commitment of Ea, and the third year is the same as the second and so on. In fact, each year we are adding the same energy commitment, for as long as the geometric growth continues. Now consider the multiyear solution obtained by stacking (superposing) the single year solutions. The stacked solution for OLR approximates to F(t) for t is less than te and becomes a constant negative Ea thereafter. (This is an algebraic identity. I won’t prove this here, but you can confirm it numerically for yourself on a spreadsheet in a matter of minutes.) This is not “runaway” warming. It corresponds to a linear increase in planetary temperature after time te - exactly what one would expect given a logarithmic relationship between CO2 and equilibrium temperature and a geometric growth in CO2. Note also that since f(t) all sits on one side of the zero line, the integral form F(t) is MONOTONIC decreasing (or increasing in a negative direction) irrespective of the choice of functional form for f(t). In the real world, we would not expect to see the monotonic OLR response implied by this solution, but we would expect to see a decreasing trend in OLR if CO2 were the PRIMARY driver of the temperature change - for the reasons I stated in my earlier post. During this period, if CO2 were the primary driver, we therefore should have seen simultaneously a decreasing trend in OLR, a decreasing trend in brightness temperature and an increasing trend in surface temperature. The reason for the opposite signs in brightness temperature and surface temperature come from the increase in downwelling radiation from the continuously added CO2. I do not believe that one can argue (as you seem to) that thermal emissions have overtaken the effects of CO2 on OLR and at the same time that CO2 is the PRIMARY driver of heating over this period. The two things cannot be readily reconciled and indeed this position probably threatens 2nd Law. -
Marcus at 14:52 PM on 18 May 2010Species extinctions happening before our eyes
Please do cite your sources Arkadiusz. I've spent a lot of time looking at close to a dozen paleo-climate reconstructions, & the range of warming over the Medieval Warm Period is usually the same-roughly +0.7 degrees (wrt 1961-1990 average) between 600 AD & 1200 AD (or delta T of +0.012 degrees/decade) & a cooling of 0.6 degrees between 1300 AD & 1600 AD, or -0.02 degrees per decade. Neither of these climate change events come even *close* to the warming of +0.12 degrees per decade that we've seen in the last 50 years, or the almost +0.16 degrees per decade we've seen in the last 30 years-especially when one considers the lack of forcings! -
quokka at 14:39 PM on 18 May 2010Skeptical Science housekeeping: navigation, comments and Thai translation
Wrt to a glossary, one of the easiest ways of getting started may be to contact other friendly sites that have one and ask permission to reproduce portions (or even the whole thing) with appropriate acknowledgements. Even organizations such as NOAA might be agreeable. I'd expect some conditions such as verbatim transcription, and a commitment to keep it up to date, which is fair enough. -
Tom Dayton at 14:22 PM on 18 May 2010CO2 measurements are suspect
johnd, you're now moving on to the topic of CO2 residence time, which has a considerable number of facts and links on a different thread: CO2 has a short residence time. We all can continue this conversation over there, if that's the topic onto which you are moving. -
johnd at 13:56 PM on 18 May 2010CO2 measurements are suspect
Tom Dayton at 12:26 PM, thanks for that article, it goes part of the way, the other part being how the variations in CO2 levels interacts with plants that are far closer to CO2 starvation levels than optimum. Do they take in more when the CO2 levels are higher, thus stripping the CO2 out at a higher rate? What the article indicates firstly is that understanding of the processes is still very limited, and that what occurs in the real world of complex and infinitely variable conditions is vastly different, not only from what is at times studied in laboratories under fixed and tightly controlled conditions, but also from some of the rather simplistic generalisations by which many of the AGW subjects are understood by many. This limited understanding of the processes as indicated in the article is perhaps reflected in the differences between some of the modelled and observed data. What is also clear from the article is that the transportation of CO2 at the near surface occurs as part of the weather system which is all about the redistribution of heat energy. What is does not address is the relationship between the belief that CO2 has a residence time of a century or more when the movement of CO2 near the surface satisfies the more immediate requirements of the plants, soil and oceans as both a source and a sink for carbon that requires an equivalent amount of the total atmosphere to be turned over every 3.5 years approximately. Is it that the CO2 high in the atmosphere plays no part in the surface exchanges and is merely the remainder left over? If so does the measurement of this non active participant include or allow for the more variable and highly mobile CO2 at the surface? One wonders whether a statistician studying the utilisation of a swimming pool only counts those passive sunbathers lying on the lawn soaking up the solar energy, using them as a convenient indicator, or does he also count those swimmers who are constantly climbing out of the pool onto the edge and shaking off moisture before diving in again. Getting an accurate count of one group would be easy, nigh impossible for the other in a crowded pool. -
Tom Dayton at 13:46 PM on 18 May 2010CO2 measurements are suspect
johnd, a less technical and much shorter explanation of CO2's thorough mixing in the atmosphere is given on page 8 of the EPA's Response to Public Comments, Volume 2, in the section "Response 2-8":"...turbulent mixing (e.g., through wind and convection) dominates the distribution of gases throughout the atmosphere (below 100 kilometers in altitude). The mixing of substances in a gas or fluid is only dependent on mass when the gas or fluid is perfectly still, or when the pressure of the gas is low enough that there is not much interaction between the molecules. Therefore, all long-lived gases become well-mixed at large distances from their sources or sinks over a period of one to two years...."
You should also read Response 2-3, regarding lifetime. And some of the nearby Responses. -
Ned at 12:51 PM on 18 May 2010On the reliability of the U.S. Surface Temperature Record
For a while Watts et al. were saying the problem was the decline in numbers of rural stations, or high-latitude stations. When it became clear that neither of these affects the temperature trend, I began noticing more and more contrarians saying that it's all because of airports. Now, Clear Climate Code has done a nice analysis showing no real difference in trend between airport and non-airport sites -- or, insofar as there is a difference, airport sites have had less warming than non-airports. So, once again, Watts etc have been quick to jump to conclusions with no evidence, and then were proved wrong when somebody actually bothered to sit down and do a quantitative analysis. It's, like, deja vu all over again! -
Tom Dayton at 12:26 PM on 18 May 2010CO2 measurements are suspect
johnd, maybe this article by Parazoo et al. has the kind of info you're looking for. -
nofreewind at 11:25 AM on 18 May 2010Species extinctions happening before our eyes
Can anyone comment on why this article,Where Are The Corpses?, is not valid. It does not discuss reptiles and amphibians, but looks at birds and mammals. -
Ned at 11:21 AM on 18 May 2010CO2 measurements are suspect
I agree with Doug that johnd needs to be more clear about what specifically he's claiming. Looking back up-thread to johnd's comment here, I see the question "What would be the means that allows CO2 to be well mixed in the atmosphere whereas heat is not." The main answer to that is "residence time." The residence time of CO2 in the atmosphere is very long (on the order of a century or so). The residence time of heat in the atmosphere is very short. (Water vapor, one of the vehicles for heat in the atmosphere, has a residence time of about nine or ten days). Thus, CO2 sticks around long enough to become well-mixed, while heat does not. -
Doug Bostrom at 09:49 AM on 18 May 2010CO2 measurements are suspect
Sorry johnd, you've lost me, I don't understand what you're driving at. I think you're saying that heat has something to do with the carbon cycle, and that unless CO2 is "stirred" up somehow and driven into contact with the surface the carbon cycle can't work? That's what I take from your post here, anyway. I don't know why you're asking me whether I think there's a carbon cycle in operation. Something to do with my question about mixing of other gases, I suppose. -
johnd at 09:41 AM on 18 May 2010CO2 measurements are suspect
doug_bostrom at 09:04 AM, please correct me if I am wrong, but the carbon cycle and the sequestration and liberation of CO2 at the earths surface by plants, soil and oceans has been established as a fact, and gone beyond being a hypothesis. Yes or no? With regards to heat, perhaps if you provided some data regarding the processes that you feel surely would apply to the mixing of O2 as they do to CO2, then we will have some basis to examine as to whether they do or not. Given oxygen makes up over 20% of the atmosphere whereas CO2 is a minor trace gas, the means that would have to be applied so that such a minor trace gas will become evenly distributed could be expected to apply to all other elements present in the atmosphere, including heat which always seeks to find equilibrium. -
Doug Bostrom at 09:04 AM on 18 May 2010CO2 measurements are suspect
Johnd, just so we're clear, I understand you to hypothesize that some concentration of C02 is required at the surface in order for the carbon cycle to work? Or are you saying that we -ought- to see a concentration of C02 at the surface -if- there is a carbon cycle? Your original explanation is leaving me scratching my head. What does heat have to do with it? -
johnd at 07:27 AM on 18 May 2010CO2 measurements are suspect
doug_bostrom at 05:01 AM, since when has the sequestration and liberation of carbon between the atmosphere and the plants, soil and ocean been returned to being a mere hypothesis. Perhaps the data on what proportion of atmospheric oxygen is involved in similar exchange processes at the surface as CO2 would provide a clue. What does that tell you? The carbon cycle requires CO2 to be sequestered at the very surface of the planet from where it is also liberated. On an annual basis about 200Gt of C is sequestered and 200Gt liberated by processes that occur at the surface. This is out of a total of 750Gt of C present in the air giving an equivalent total turnover time of 3.5 years. If a similarly high proportion of oxygen does turnover within a similar time frame than surely you would agree that heat distribution throughout the atmosphere would also be well mixed, oxygen being such a high proportion of the atmosphere rather than a trace gas? -
Doug Bostrom at 07:12 AM on 18 May 2010Increasing CO2 has little to no effect
Babelsguy, your friend apparently has not so much a quibble with C02 as a GHG so much as he does with the concept of an atmosphere being able to trap heat. After all, what he believes applies to any GHG. How does he explain why Earth's climate is not the same as that of a planet with no atmosphere? -
Steven Sullivan at 07:11 AM on 18 May 2010It's cooling
Oh joy, we're about to get another revival of this argument http://climatedepot.com/a/6574/search.asp?cx=partner-pub-2896112664106093%3Am5ewh74pu5c&cof=FORID%3A9&ie=ISO-8859-1&q=global+cooling "Geologist Declares 'global warming is over' -- Warns U.S. Climate Conference of 'Looming Threat of Global Cooling' " -
babelsguy at 05:08 AM on 18 May 2010Increasing CO2 has little to no effect
A related question about the basics of the greenhouse effect: I have been sent a "study" by a guy who claims that CO2 cannot be a greenhouse gas because any warming would cause an instant increase in outward radiation due to the increased temperature difference between the atmosphere and open space, which would immediately diminish the warming. I tried to discuss some sense into him, but in classic denier fashion, he remained stubborn that nobody so far could give him a "convincing" reason why his objection cannot be true. I tried the earth system's heat capacity, speed of propagation of temperature changes in a kilometer-thick atmosphere, dynamic equilibrium, I even quoted the paragraphs from "A History of Global Warming" at aip.org that say that the actual greenhouse effect is caused by a greenhouse gas concentration change at the tropopause, effectively shifting it into higher, cooler layers of the atmosphere, which radiate heat less effectively than warmer layers, which forces the whole of the temperature gradient in the atmosphere to do something like a parallel shift in order to achieve a high enough temperature at the tropopause to force enough radiation out into space to re-establish the equilibrium - all to no avail. What would you experts here tell him (assuming he might still be convinced)? Any reply very much appreciated! Cheers, babelsguy -
Doug Bostrom at 05:01 AM on 18 May 2010CO2 measurements are suspect
Johnd, surely the same processes you hypothesize in your #25 would apply for 02 as well? -
johnd at 04:04 AM on 18 May 2010CO2 measurements are suspect
doug_bostrom at 03:47 AM, I don't have the appropriate data available, perhaps you will have, what is the proportion of atmospheric oxygen that is involved in exchange processes at the surface, or elsewhere for that matter? -
Doug Bostrom at 03:47 AM on 18 May 2010CO2 measurements are suspect
Johnd, what about other gases? Forgetting C02 for a moment, how about molecular oxygen? Well mixed? Not well mixed? -
johnd at 03:39 AM on 18 May 2010CO2 measurements are suspect
What would be the means that allows CO2 to be well mixed in the atmosphere whereas heat is not. Heat content varies from one extreme to the other not only with altitude but across all the regions of the world. One would expect that whatever mechanism controls the transportation of CO2 would also be involved in the transportation of heat. Given that the amount of CO2 that is pumped into the atmosphere by the combustion of fossil fuels is very small compared to the quantity of CO2 that is in constant exchange between the atmosphere and the surface, about 1/60th, either the concentration of CO2 will be higher right at the surface where the exchange takes place or there are very violent forces in place that if able to transport and distribute the CO2 given up by the plants, soil and oceans has to be matched by perhaps even greater violent forces that has to search the entire atmosphere and gather the CO2 up to concentrate it and physically transport it back to the surface, all without doing the same to the heat contained in the environments that well mixed CO2 would find itself. Either that or the CO2 exchanged through natural processes stays very close to the surface. It is very clear how the local CO2 levels vary considerably during the plant growing seasons around the world which generally coincide with more stable and benign weather systems, and also from the experiences of decades of CO2 enrichment experience in the greenhouse industry producing plants and food, where CO2 levels can vary considerably within each greenhouse itself requiring forced circulation that not only ensures that the required levels of CO2 are evenly distributed to the plants, but also the heat, and one cannot be redistributed without the other. -
Martin at 03:39 AM on 18 May 2010Woody Guthrie award to The Science of Doom
Just had a look. Excellent! BTW I was reading his post on "Models, On – and Off – the Catwalk – Part Two". The last comments are an exchange about what consitutes V&V (Verification and Validation) in a climate model. I'm not an expert. I've just got the feeling that climate models can't be quite as bad as one commentor puts it even if they haven't been validated in the same way as Boeing’s computer models of airplanes. Do you have a view on this issue? -
tobyjoyce at 03:27 AM on 18 May 2010Woody Guthrie award to The Science of Doom
Great blog. We needed a site that explained the mathematics and physics of global warming. I know there are some, but this is the best I have seen so far. -
thefrogstar at 03:18 AM on 18 May 2010Woody Guthrie award to The Science of Doom
Many thanks. Good choice. I've just visited the SoD site for the first time. It appears excellent. -
Phila at 02:44 AM on 18 May 2010Species extinctions happening before our eyes
#50 Arkadiusz Semczyszak "In the nineteenth century, glaciers in the Alps were moving at a speed of (locally) up to 3-4 meters per day in one (...) destroying entire ecosystems." Statements like this would be more useful if you provided a cite, and some sort of context. Better formatting might also help to make your arguments more intelligible. As for your quote from Lonnie G. Thompson, it seems safe to say that Dr. Thompson draws very different conclusions from his life's work than you do. von Gunten et al. (2009) -
chris at 01:59 AM on 18 May 2010Species extinctions happening before our eyes
Arkadiusz If it's "high time to abandon the Mann hockey stick" then why do you guys keep obsessing about it?...and if as you say "Since 1998 science has changed" why do you ignore the wealth of data on this subject from the last 6 or 7 years, and continually hark back to 12 year old papers? In fact no one talks very much about Mann et al 1998/1999 these days (although the data continues to be displayed in reviews on the subject that covers the entire paleoreconstruction field). After all this is 12 year old research and there have been numerous paleoreconstructions in the intervening years. These all yield pretty much the same conclusions about Northern hemisphere temperature as originally presented all those years ago. You can find them all in the NOAA repository of paleoreconstructions. I don't think any of them show what you suggest (what data are you referring to in your post?). I've had a quick look at the following reconstructions [***] (URL's available on request) and none of them show the odd features (periods warmer than 20th century between AD 1150 and 1350 and "sharp drops between AD 1350 and 1400". In fact none of them show maximum temperatures in the NH of the last 2000 years greater than the mid-20th century global average, and most of the published paleoreconstructions show temperature rises during the period AD 1350-1400. So what have you been looking at??? [***] D. S. Kaufman et al. (2009) Recent Warming Reverses Long-Term Arctic Cooling Science 325, 1236-1239 M. E. Mann et al (2008) “Proxy-based reconstructions of hemispheric and global surface temperature variations over the past two millennia” Proceedings of the Natl. Acad. Sci. USA 105:13252-13257 Lee TCK, Zwiers FW, Tsao M (2008) “Evaluation of proxy-based millennial reconstruction methods.” Clim Dyn 31:263–281. Hegerl GC et al (2007) “Detection of human influence on a new, validated 1500 year temperature reconstruction.” J Clim 20:650–666. D'Arrigo RD, Wilson R, Jacoby G (2006) “On the long-term context for 20th century warming.” J Geophys Res 111:D03103. Viau, AE et al (2006) “Millennial-scale temperature variations in North America during the Holocene” J. Geophys. Res. 111, D09102. Moberg, A. et al. (2005) Highly variable Northern Hemisphere temperatures reconstructed from low- and high-resolution proxy data. Nature 433, 613-617 dfjdkh -
Ned at 01:38 AM on 18 May 2010CO2 measurements are suspect
Johno writes: Satellites are beginning to debunk the idea that CO2 is "well-mixed" in the atmosphere. More data is needed, but the early indications prove Chris is out on a limb when assuming such an unfounded idea. Did you see the video linked above, which shows a year of satellite data? Note the scale at the bottom. Over the entire year and the entire globe, CO2 ranges from ~375 to ~390 ppmv. That's pretty well mixed, IMHO. -
hammiesink at 01:12 AM on 18 May 2010There is no consensus
Poptech, Science is decided by evidence, not signers of petitions. The reason almost all major scientific institutions agree with the mainstream view of global warming is because the scientific evidence overwhelmingly supports it. Notice the consistency on one side of the debate: CO2 is rising, leading to warmer temperatures and a potentially serious problem that should be mitigated. Compare to the inconsistency on the skeptic side: it's not warming, it is warming but it's the sun, it's not warming, it is warming but it's el nino, CO2 is causing warming but climate sensitivity is low, it's cooling, it's warming but it's cosmic rays, it's warming and it's CO2 but cap and trade sucks, the hockey stick has been debunked, it's cooling, it's warming but it's water vapor, it's cooling because of the sun, it's a statistical mistake, it's warming, it's cooling. Is that about it? Did I succinctly summarize the "skeptic" position correctly? -
Alexandre at 00:29 AM on 18 May 2010Woody Guthrie award to The Science of Doom
I'm a regular visitor to the Science of Doom blog. I've learned a lot about the basics of the physics involved, and he's usually available to answer directly to my amateur questions. Now I have the selfish feeling that he'll get more known and visited and won't be that available anymore... He deserves it. Good choice. PS: For new visitors, I would suggest to take some time and read the CO2 series from the beginning. It's well worth it. If you want to have an opinion about something, you must understand it first. -
sylas at 00:24 AM on 18 May 2010Woody Guthrie award to The Science of Doom
I discovered science of doom quite recently, and was enormously impressed. Well chosen indeed. -
Arkadiusz Semczyszak at 23:59 PM on 17 May 2010Species extinctions happening before our eyes
Marcus "... quantitative evidence for the presence of a Medieval Climate Anomaly (in this case, warm summers between AD 1150 and 1350; ΔT = +0.27 to +0.37°C with respect to (wrt) twentieth century) and a very cool period synchronous to the 'Little Ice Age' starting with a sharp drop between AD 1350 and AD 1400 (-0.3°C/10 years, decadal trend)... [!!!]" (2009). The present warming (last 50 years in the twentieth century) is not even half of that ... In the nineteenth century, glaciers in the Alps were moving at a speed of (locally) up to 3-4 meters per day in one (...) destroying entire ecosystems. Marcus - high time to abandon the Mann hockey stick ... Since 1998, science has changed ... Even the IPCC has said that the former does not change the temperatures were in the hundreds and thousands of years - L. Thompson - IPCC - "This abrupt event, ≈5,200 yr ago, was widespread and spatially coherent through much of the tropics and was coincident with structural changes in several civilizations. These three lines of evidence argue that the present warming and associated glacier retreat are unprecedented in some areas for at least 5,200 yr." ... and so I could enumerate dozens, dozens of works from the last years. Natural strong climate change is likely always been sudden. -
JMurphy at 23:54 PM on 17 May 2010Climate Change and the Integrity of Science: a letter to Science
neilperth, you answered your question by the examples in your second paragraph - even though we all know what the problems are, we won't do anything about it until it affects us personally and directly. You could also see the inaction from politicians before the credit crunch, even though many economists, etc. had been predicting it and we were all just basically waiting for it to happen. I'm not sure how much of a threat comes from an increase in human population, though - as long as there is enough food, water, work, etc. The main threat will be the way climate change impacts on that food, water, work, etc. -
Johno at 23:28 PM on 17 May 2010CO2 measurements are suspect
Satellites are beginning to debunk the idea that CO2 is "well-mixed" in the atmosphere. More data is needed, but the early indications prove Chris is out on a limb when assuming such an unfounded idea. In addition, the argument against taking CO2 readings in cities is clearly specious. Long term CO2 trends should be as readily apparent as long term temperature trends. Of course, the data from cities will be as polluted by urban growth as are temperature records, but the results would still be useful. -
jimalakirti at 22:54 PM on 17 May 2010Woody Guthrie award to The Science of Doom
Science of Doom is a great choice. Thanks for pointing it out.A lot of my readers and I have been looking for an information source just like this. -
Marcus at 22:45 PM on 17 May 2010Species extinctions happening before our eyes
Also, there is plenty of evidence to suggest that rapid methane release-& resultant *warming*-caused the mass extinction at the Permian/Triassic boundary, & a lot of evidence to suggest that the original Cretaceous impact that wiped out the dinosaurs probably led to "rapid" warming, before the planet got cold. So I'd suggest you need to check your facts a bit more carefully in future Arkadiusz. -
Marcus at 22:41 PM on 17 May 2010Species extinctions happening before our eyes
Wrong again Arkadiusz Semczyszak. Take a look at all the temperature proxies for the last 12,000 years & what do you see? I see temperature rises of a similar magnitude to recent warming-but over a period of CENTURIES OR EVEN MILLENIA! By modern day standards, these warming events have actually been incredibly slow. Even in all the previous Interglacial Periods where the planet was moving closer to the sun-& the change in temperature was on the order of 8 to 12 degrees Celsius-it was still occurring over tens of thousands of years (one warming event, 150 kyrs before the present, took 25,000 years for a 10 degree warming to occur-or +0.004 degrees per decade, nearly 20 times *slower* than in the modern age). So please spare us this talk about past warming being "really sharp"-they were actually quite dull compared to everything we're currently doing. Yet if these relatively *slow* warming periods could cause mass extinctions, then what potential for extinction is there in this more rapid warming phase? -
dorlomin at 22:07 PM on 17 May 2010Woody Guthrie award to The Science of Doom
I have been a huge fan of that blog as well. An excellent addition to the blog roll. -
CBDunkerson at 21:44 PM on 17 May 2010Species extinctions happening before our eyes
On the whole 'local extinction is not extinction' bit... actually, this is not always true. There are differing definitions of the word 'species', but most are close to the concept of a breeding population. However, we can't track the breeding habits of every animal in the world and don't really know if two animals from opposite sides of the planet would breed fertile offspring or not. Thus, we generally ASSUME that animals which LOOK alike are members of the same species. Modern genetic science has proved over and over again that this assumption is wrong as often as not. In many cases what we call a 'local population' of a species is, in fact, a DIFFERENT species which looks very similar but has significantly different DNA and cannot interbreed. Read up on cryptic species to see what I'm talking about. Also a news article on a recent example of discovering that such a 'local population' was actually a separate species. Thus we can be quite certain that some of these 'local extinctions' are in fact the TOTAL extinctions of distinct species which had just not been classified as such yet. -
Riccardo at 21:06 PM on 17 May 2010Climate Change and the Integrity of Science: a letter to Science
neilperth, I think this is the realm of sociology. Science tells us what the threat is, societies may choose not to see, at least for a while. This behaviour is not at all new in human history. It makes me think about the famous Asimov's short story Nightfall, definitely worth a reading. -
Arkadiusz Semczyszak at 19:01 PM on 17 May 2010Species extinctions happening before our eyes
"The fossil record shows us that mass extinction events coincided with periods of dramatic climate change." As an environmentalist (dynamic ecology) I have to take a voice. The emergence of human civilization has led to the great extinction (which takes out) by: 1. Sharp reversal of natural ecosystems to agriculture. 2. Habitat fragmentation (anthropogenic barriers hindering migration in the case of climate change - temperature), and depletion of natural environments (the exploitation and pollution). Under these conditions, any even the smallest variation in temperature can lead to the extinction of many species. ... but: 1. Current temperature change is indeed, but not violent. Her "unprecedented" is long-term sustainable growth temperatures. 2. Remember that it is always cool = reduce the number of species - selection, warming = adaptive radiation; ecosystems with the greatest biodiversity is warm ecosystems. Arctic Ecosystems area (the NPP) are often based only on a few species of algae. Indeed it is often (NPP) greater than in the tropics, in tropical al is their (algal species), hundreds ... Interestingly, even the polar bears were created during one of the interglacial’s - allowing the expansion to the north of Grizzly Bear. Conclusion: warming (at current rates) will help considerably larger number of species to survive the current anthropogenic pressures and lead to the elimination of rare species, as a rule, and so are at the end of its "evolutionary road". 3. Studies targeting potential adaptive responses to changes in temperature, are often fragmented and concern over a short period of time (at least claims about the oceans, professor Jean-Pierre Gattuso - Programme Arctic EPOCA). Geological studies are too vague. "For example an assessment of amphibian extinction rates estimates this at more than 200 times the background rate." In particular, insects and amphibians because of their enormous potential reproductive and breeding create a large number of so-called. "ephemeral species". Their "evolutionary life" has always been short (which uses such as Professor Tim Flannery). "Did a large meteorite (as measured by Iridium distributions) cause the mass extinction of the dinosaurs (I'm not sure if this is what is meant by the Permo-Triassic extinction)?" Probably all the great extinctions caused rapid cooling (no warming). The Permo-Triassic extinction - anoxia - is still only a "fashionable" hypothesis ... So what do you need? Instead of spending money to fight AGW, above all, should be used to reduce fragmentation of natural environments. In the past temperature changes were really sharp and I'm sure this will be in the future ... -
Phila at 16:19 PM on 17 May 2010Species extinctions happening before our eyes
The complaints about the term "local extinction" seem to me to be missing the point. The regional loss of a species can have huge repercussions, both for other plants and animals and for humans who rely on them. (It could even have consequences for tourist economies, in some areas.) Re-introducing a species may be possible, depending on how much time has passed, whether the problem that caused the initial extinction has been solved, etc. If AGW is the problem, it could be some time before re-introduction is feasible, to put it mildly. (Which reminds me: One of the stranger tendencies on the "skeptic" side is to claim, often simultaneously, that extinction is perfectly normal, and that a given animal or plant will be fine because it'll simply adapt to AGW. I'm not sure you get to have it both ways.) -
neilperth at 14:37 PM on 17 May 2010Climate Change and the Integrity of Science: a letter to Science
I was thinking the other day............If so called "climate change" is proved and it's adverse effects on us as humans are so obvious,as you imply, why are the world's politicians doing next to nothing about it ? This seems rather odd to me. The human population increase has been a threat to humans for years but again not much is done about it - likewise lack of food and disease in certain areas of the world. -
Ron Crouch at 11:19 AM on 17 May 2010Species extinctions happening before our eyes
Speaking of which: according to the latest United Nations Global Biodiversity Outlook report. Quote:"Noting that the world has failed to meet its target to achieve a significant reduction in the rate of biodiversity loss by 2010, the report stressed that with the current rate of biodiversity loss, there will be “a severe reduction of many essential services” provided by nature to human societies, as ecosystems reach their limit and shift to alternative, less productive states, “from which it may be difficult or impossible to recover.”" -
Don Gisselbeck at 11:10 AM on 17 May 2010Species extinctions happening before our eyes
Aren't humans just about the ultimate weed species? Am I being too optomistic hoping that all we are doing is fighting for the survival of civilization? -
Ron Crouch at 09:24 AM on 17 May 2010Species extinctions happening before our eyes
Migration has it's limits as well. It is well within the realm of possibility that some species will have no place to migrate to and will finally go extinct (some migrations being vertical while others follow a lateral pattern). Some species will go extinct as a result of being displaced by the migration of other species. And let's not forget the other pressures we place upon species through loss of habitat and pollution. Someday we may find ourselves on the "endangered species list". -
chris at 07:40 AM on 17 May 2010Species extinctions happening before our eyes
thefrogstar at 06:41 AM on 17 May, 2010 frogstar, there has apparently been a long standing uncertainty over whether it was the Chicxulub asteroid impact, or an earlier (or later?) impact whose crater hasn't been found (under the sea?), or whether the massive flood basalt eruptions that produced the Deccan Traps in now-India was responsible (or a major contributor; e.g. the Deccan Traps resulted in a long term stressing and the impact delivered the coup de gras). Very recent reassessment of all the data seems to point to the Chicxulub asteroid impact being the cause of the end-Cretaceous extinction that did for the dinosaurs 65 MYA (and set the stage for the wonderful world of mammals!). The Permian-Triassic extinction was 251 MYA and was a particularly brutal mass extinction. -
chris at 07:11 AM on 17 May 2010Species extinctions happening before our eyes
batsvensson at 06:24 AM on 17 May, 2010 sorry, batsvensson; I drifted into British yoof colloquialism! I meant "massive" in the sense of "large". It's not straightforward to determine extinction rates, and these are presumably always estimates (both of the natural background rate and whatever current rate one is attempting to compare). However estimates of current extinction rates put these at 10's to 100's of times the background rate. For example an assessment of amphibian extinction rates estimates this at more than 200 times the background rate. I believe the estimated extinction rates of reptiles are similarly high. M. L. McCallum (2007) Amphibian Decline or Extinction? Current Declines Dwarf Background Extinction Rate J. of Herpetology 41:483-491 -
thefrogstar at 06:41 AM on 17 May 2010Species extinctions happening before our eyes
Yes, John, my bad (#29). CO2 was there in the penultimate sentence. I shouldn't try and do science on a Saturday night. Some of the later posts re-ignite a question I've asked of geologist-friends before, but not got a satisfactory answer to. That is: Did a large meteorite (as measured by Iridium distributions) cause the mass extinction of the dinosaurs (I'm not sure if this is what is meant by the Permo-Triassic extinction)? Or was it something else? I've also read that the extinction occurred over a period of greater than a million years, which doesn't seem much related to a cataclysmic impact of either climate or meteorites. -
batsvensson at 06:24 AM on 17 May 2010Species extinctions happening before our eyes
chris at 23:47 PM on 15 May, 2010 "The reality is that species extinctions are occurring at a massively faster rate than the background extinction rates." I am curious as to what you mean when you say "massively faster rate" above. Is it massively as in mass-extinction rate or some else rate?
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