Recent Comments

Prev  719  720  721  722  723  724  725  726  727  728  729  730  731  732  733  734  Next

Comments 36301 to 36350:

36301. scaddenp at 19:07 PM on 29 May 2014
       The Wall Street Journal denies the 97% scientific consensus on human-caused global warming
       

       I could ask, if coal is cheap, then why do US coal producers need subsidies and protection?

36302. Tom Curtis at 19:02 PM on 29 May 2014
       The Wall Street Journal denies the 97% scientific consensus on human-caused global warming
       

       austratsua @4:

       "Firsly, it is unseemly to attack people who disagree with you with terms like "denier"."

       Firstly, despite your complaint, nobody was called a "denier" in either the original post, nor in the three comments that preceded yours.  Rather, it was said that certain people deny certain propositions, ie, they claim that those propositions are false.  You are so determined to control the terms of the debate that even use of simple verbs to describe the beliefs of others is now not OK with you.

       So, here are two simple questions:

       1)  Do Bast and Spencer claim that there is not a 97% consensus of climate scientists who agree that >50% of recent global warming was caused by anthropogenic factors?

       2)  If Bast and Spencer do make that claim, why do you react so strongly against the simple description that they deny that claim?

       Secondly, despite you concern about how unseemly the missing attack was, you seem unconcerned that Spenser should refer to climate scientists as "Global Warming Nazi's", unconcerned about Bast's use of billboards to draw a connection between AGW and the Unabomber, unconcerned about the frequent accusations that climate scientists are guilty of fraud (scientific, and less frequently) financial, an unconcerned about accusations that people seeking policy action against AGW are routinely accused of desiring genocide by your fellow pseudo-skeptics.  Absent evidence the contrary, in the form of links to comments where you have protested such activity by your fellow pseudo-skeptics, I will conclude that your concern for civility is, like that of most of your fellow travellors, one sided and hypocritical.

       The simple fact is that concern about the term "AGW denier" does not arise from genuine feelings of offense.  They arise from the same desire to win the debate by persuasive definitions that led pseudo-skeptics to call themselves "skeptics".  It is an attempt to controll the debate by controlling the language used in the debate.   As with Orwell's "Big Brother", it shows a determination to controll the language to limit what can be thought.

36303. chriskoz at 18:57 PM on 29 May 2014
       Rapid climate changes more deadly than asteroid impacts in Earth’s past – study shows.
       

       Thanks Howard for another innteresting article about extinction.

       I want to understand this sentence:

       The authors note that the correlation between LIPs and severe extinctions is now so strong that there is a “negligible 6×10^–9% probability that such correlation is due to chance alone,”

       (my emphasis)

       I'm not sure, if you refer to http://dx.doi.org/10.1016/j.palaeo.2012.06.029 as the source of that sentence because I don't have free access to it. So I want to confirm with you wheather this number is or is not a typo. How can we be so sure about the causes of events so deep in the paleo (60-500Ma)? What do you mean exactly by "due to chance alone" and how do you exclude an event so defined with such inbelievably high certainty?

36304. Doug Bostrom at 18:45 PM on 29 May 2014
       The Wall Street Journal denies the 97% scientific consensus on human-caused global warming
       

       "cheap coal that could allow them access to clean water and clean air"

       That's rather hysterically funny. 

       Here's what cheap, clean coal looks like in situ where "they" enjoy it : 

       

       With regard to risk aversion, we're all in this car together and (to stretch the metaphor) there are no seatbelts. I for one would rather have a cautious driver at the wheel, "inflicting" risk aversion on me, rather than a reckless fool doing the driving. 

       Doubtless folks wringing their hands about poverty in the 3rd World have already exhausted their own personal means of correcting that problem, for surely they would not be using such an emotional appeal as a cheap rhetorical expediency. 

36305. scaddenp at 18:38 PM on 29 May 2014
       The Wall Street Journal denies the 97% scientific consensus on human-caused global warming
       

       "Should wealthy risk-averse westerners be allowed to force poverty-stricken Indians and Chinese not to have access to cheap coal that could allow them access to clean water and clean air and a good life?"

       Show me where this has been suggested. You could try discussing things seriously instead of jumping into cheap rhetoric. Or do actually believe this from reading misinformation somewhere? In fact the usual suggestion is to let non-Western countries increase FF use while alternatives are slowly brought in while the affluent West very sharply reduce their emissions. That would have been substance of all recent climate conferences.

       It would be reasonable to hold alternative opinions to AGW if there was actually some data to support some other idea as opposed to, yes, denialism, and misinformation campaigns. If you really think that this exists by all means present the evidence on an appropriate thread.

36306. billthefrog at 18:05 PM on 29 May 2014
       Rapid climate changes more deadly than asteroid impacts in Earth’s past – study shows.
       

       @Tom & Glenn          - Thank you

       @ Graham                 RE: the RCP guide- Wow

36307. ranyl at 17:46 PM on 29 May 2014
       The Wall Street Journal denies the 97% scientific consensus on human-caused global warming
       

       "Based on this quote the author is so sure that anthropogenic global warming is true that he thinks it's as obvious as the fact that the earth goes around the sun."

       That CO2 is a Greenhouse Gas and warms the planet is as certain as the earth's goes round the sun. And this physical truth of global warming has gone through the progression from hypothesis, to theory, to accepted common knowledge, with all the trials and tribulations of peer review with several counter theories and arguments put against it over some 150years or so.

       That this warming is amplified by the earth's internal systems (the climate sensitivity) has also gone through the same rigorous progression.

       The uncertainty is how much the earth's internal system amplify the warming and consensus on an exact figure for this is hard to find, for 2 reasons, there are uncertainties in the measurements (like all measurements) and the system is complex and behaves chaotically, meaning that the climate sensitivity is dependent on the initial conditions of the system, in this the earth's continental arrangement, amount of sea ice present, amount of oceanic ice, amount of O2 etc, over geological time and thus is a moving target overall. Being in a time when there is large oceanic ice cover to melt away quickly is suggestive that this might be a time of higher CS than at others. As climate being dangerous, well as in the previous article this week, when CO2 and SO2 are released in large amounts into the atmosphere life can be dramatically reduced it appears, and although that is open to question, as the evidence mounts it is well into the established theory realm and thus most scientist would agree that global warming induced by burning coal can be quite dangerous I would suspect.

       Maybe the authors should put out an scientist e-mail and ask several thousand that question sure they find that most would feel that climate change can be very dangerous to life per se never mind a complex civilization with ~50% of its population and more of its wealth near the ocean edge when sea levels are set to rise.

        

        

36308. austrartsua at 15:18 PM on 29 May 2014
       The Wall Street Journal denies the 97% scientific consensus on human-caused global warming
       

       Wow, where to begin. Firsly, it is unseemly to attack people who disagree with you with terms like "denier". Criticism is central to scientific progress. You never know, you might actually improve your methodology if you listen rationally to criticism. Calling them "denier" and talking about irrelevent facts about their history and rupert murdoch is at best "post-modern" and at worst a cynical attempt to evade the criticism.

       "By that standard, there’s less than a 1% expert consensus on evolution, germ theory, and heliocentric theory, because there are hardly any papers in those scientific fields that bother to say something so obvious as, for example, “the Earth revolves around the sun.” The same is true of human-caused global warming." 

       Are you seriously suggesting that the the earth's climate is as well understood as the heliocentric theory or evolution? Have you heard of scientific fallabalism? It goes like this. A new theory is always assumed to be wrong. This is the default position. Based on this quote the author is so sure that anthropogenic global warming is true that he thinks it's as obvious as the fact that the earth goes around the sun. If all scientists thought this way they would never be able to correct their mistakes and they would hold on to theories no matter what data comes in.

       
       "if the 97% expert consensus is right, it means we’re in for several more degrees of global warming if we continue on a business-as-usual path." This is false. The consensus quoted in your paper said nothing about how much the world will warm in the next century. In fact the criteria did not require any quantification of the amount of warming in the future or in deed in the past 150 years. Accordingly, one could rightly claim to belong to your consensus and still predict relatively little warming over the next century. And then there is the issue of dangerousness. You are right to say that some people are more risk-averse than others. But does this mean that highly risk-averse people should be able to force those who are not so risk averse to pay more for energy? Should wealthy risk-averse westerners be allowed to force poverty-stricken Indians and Chinese not to have access to cheap coal that could allow them access to clean water and clean air and a good life? 

36309. davidnewell at 13:48 PM on 29 May 2014
       It's too hard
       

       davidnewell at 13:13 PM on 29 May, 2014
       As more and more evidence accumulates in regard to the looming catastrophe, more serious consideration may be given to ways to counter at least the rate of increase, so that more time is available to employ other methods, and educate "the masses".

       Somewhere here someone took some "shots" at the technique found at

       WWW.EarthThrive.Net,

       mumbling a dismissive comment relating to the amount of CO2 dissolved in the Gulf Stream, or something.. Totally non-bearing on the proposal.

       ===============

       I propose to defend the matter, thru simplicity.l. Many here may find "fault",

       but it's hard to argue against this..

       =========================

       I propose a "new measurement" of alkalinity.
       Maybe it's NOT new, but it's new to me, and facile for raising my point.

       Total Alkalinity, volume, (vs. CO2) = volume of pure CO2 adsorbed / volume of solid substrate

       Abbreviated TA(sub)v or TAv, it can be in any dimensional system,
       as long as they are "in common". ( of course)

       My laboratory measurements were in CC.

       Ranges of TAv for surface alkali soils ranged between about 2 1/2 to over 3.

       (there are speculative reasons to think that lower levels will be more reactive..)

       I presently cannot find this (following) calculation, so anyone of interest can do so.

       Given the elongated inverted pyramid approximation of (say) the Black Lake Desert,

       which is about 25 miles long by 10 miles wide..

       Assume that it is a rectangular box 1 mile deep.

       Given a conservative TAv of 2.5, what is the weight of CO2 in tonnes possible if all the material was reacted.???????

       After that is derived, then we can see if further consideration of the other objections may be warranted.

       ==============

       Lets see: 22.4 liters^ of CO2 = 1 mole wt of CO2, in grams, at STP.

       formula wt = 44.grams/ mole

       ======================

       According to my trusty HP-55, which is still running after all these years,

       under consideration is 25X10X1, which is 250 cu miles of "dirt",

       which can ultimately sequester (with a TAv of 2.5), 625 cu miles of CO2.

       1 cubic mile =4.16818183 × 10^15 cubic centimeters
       625 " = 2.605113641 x 10 ^18 "
       or 2.605113641 x 10 ^15 liters.

       or (changing decimal pt) 26.05113641 x 10 ^17 liters,
       which, when divided by 22.4 liters, = 1.2 X 10^17 moles of CO2,
       or, multiplying by the mole weight of CO2, 44,
       equals ~5 X 10 ^ 18 grams ,
       or 5 X 10^12 tonnes.

       Anyone who used an HP55 in college is old as the hills,
       OVER the hill,
       and probably missing a screw, as well..

       Please point out my errors, other than those which are simple approximations.

       =======================

       All that is needed, urgently, is to employ a technique
       which reduces the rate of increase in circulating CO2,
       while "other measures" take effect. If we can take 5 billion tonnes
       OUT of the air, per year, we "MIGHT" have a chance.

       Pumping costs be damned!
       AT the very LEAST civilization is "under threat" by our combined ignorance.
       (This "rant" is more "refined" at www.EarthThrive.net, so I'l discontinue it,
       here..)

       For far less than Gov Moonbeam's favorite projects of continuing stupidity,
       ie the "twin tunnels" under the Delta, and/or the "Train to Nowhere",
       we could implement this plan,
       AND
       (side issue)
       produce a hell of a lot of clouds going dowwind.

       It may be noted that many of the playas (the above is just an example, although one of the larger playas, to be sure..) are "saline" in nature, and are "wet" at some depth under the surface. Maintaining conditions for bicarbonate stability (dampness) is not difficult.
       Thank you for your time.

       David Newell

       =================

36310. scaddenp at 13:15 PM on 29 May 2014
       The Wall Street Journal denies the 97% scientific consensus on human-caused global warming
       

       Moderation

       Moderator Response:

       OnePlanetForever, please take note and abide by the comments policy, noting especially the section on politics. There are plenty of other sites for political rants. Please stick to the science.

36311. Glenn Tamblyn at 10:56 AM on 29 May 2014
       Rapid climate changes more deadly than asteroid impacts in Earth’s past – study shows.
       

       Billthefrog

       Another important event around 30-35 million years ago was the separation of Sth America and Antarctica, allowing the formation of the Antarctic circum-polar current, tending to isolate Antarctica and allowing it to colmore

36312. scaddenp at 09:44 AM on 29 May 2014
       Rapid climate changes more deadly than asteroid impacts in Earth’s past – study shows.
       

       mancan18 - you might also like to have quick look at this guide to the RCPs. Economics would prevent burning everything but working out atmospheric concentrations also require taking into account how the natural systems draw-down (or otherwise) excess CO2. A typical pseudo-skeptic will argue that environment will continue to draw down 50% of emissions, ignoring that as temperatures rise, the oceans eventually emit CO2, rather than absorb it.

       You can play with really extreme scenarios but the RCPs are a far better guide to what is realistic (and frightning enough at that).

36313. billthefrog at 09:41 AM on 29 May 2014
       Rapid climate changes more deadly than asteroid impacts in Earth’s past – study shows.
       

       Thanks Howard,

       What you say pretty well reinforces what I understood from the Climate Change MOOC I recently did at Exeter University.

       The reason I put a question mark on the Palaeoproterozoic snowball/slushball event having primacy was simply cause I don't know enough about the earlier Archean Eon. Could the Faint Young Sun of those far off days have been instrumental in an even earlier snow/slush ball? Do we have enough preserved crust from that long ago to tell? I know that some zircon crystals have been radio-dated at around ~4.3 billion years, but whether there is sufficient preserved crustal material - I just don't know.

       Moving to more recent times and the Pleistocene glaciation. If my understanding is correct (cue a huge guffaw from the wife at this point), temperature wise we've been on a downward slope since the heady days of the Eocene. The Indian Plate went sailing full tilt into the Eurasian Plate starting about 65 MYA and causing (initially) a major carbon release into the atmosphere. (Chicxulub, the Deccan Traps and the start of the Himalayan orogeny - a lot of stuff going on about then.)

       About 50 MYA, the Himalayas and the Tibetan Plateau had popped up, exposing lots of nice fresh silicate surfaces just ripe for weathering - with the concommitant CO2 drawdown. (I don't really know how much credence is given to the postulated Azolla Event and its resulting major carbon sequestration which is, by some, thought to have happened at about the same time - to within a million years or so.)

       Obviously, the continents were still dancing around, getting their rocks off, so to speak. (Stealing a line from the great Terry Pratchet.) However, I understood that it was the sealing off of the Panama Ithmus that was the final piece of the jigsaw that allowed the reformation of massive polar ice sheets.

       Have I got that just about right?

36314. Tom Curtis at 09:34 AM on 29 May 2014
       Rapid climate changes more deadly than asteroid impacts in Earth’s past – study shows.
       

       billthefrog @6, while rate of change is the main driver of extinction, the Earth can, and has in the past, reached temperatures where the absolute temperature value drives extinction.  The obvious examples are the two slushball Earth episodes discussed by howardlee @12.  Equivalent episodes today would extinguish all, or nearly all complex multicellular life on Earth, regardless of the rate of onset.

       Of more concern are episodes like the end Permian mass extinction where tropical temperatures rose sufficiently to be seasonally uninhabitable.  Global temperatures of about 10 C above the preindustrial will make large sections of the tropics uninhabitable to large warm blooded vertebrates based on absolute values of wet bulb temperature.  There is evidence that the absolute limits are to be found for most complex multicellular life at temperatures about that level.

       Humans would have to be terminally foolish to raise temperatures so much that absolute limits on temperature become a major factor in extinctions.  Currently, however, terminally foolish best describes global policies on geen house gases.

36315. Tom Curtis at 09:23 AM on 29 May 2014
       Rapid climate changes more deadly than asteroid impacts in Earth’s past – study shows.
       

       mancan @18, a worst case emissions scenario would not just consume proven reserves (on which your figure is based) but a substantial proportion of the total resource base (TRB).  That is, it will access coal not currently commercially viable either due to increased energy prices, or due to improved technology (such as coal seam gassification).  Unsurprisingly, estimates of the TRB are less certain than those for proven reserves.  At the outside, determined exploitation of the fossil fuel TRB would lift atmospheric CO2 levels above 5000 ppmv (based on the IEA 2011 estimate).  At the low end, determined exploitation of the TRB will lift atmospheric CO2 levels to about 1500 ppmv (based on WEC 2010 figures).  The former will raise temperatures to levels at which multicellular life may be impossible - and certainly impossible for large, warm blooded vertebrates such as humans.  The later will lift temperatures to levels at which periodic tropical heat waves will result in 100% mortality for large, warm blooded vertebrates.  That may be devestating, even apocolyptic for the economy, but should not represent an extinction threat for humans (many of whom live outside the tropics).  Intermediate estimates will reproduce conditions very similar to those during the end Permian extinction, making the tropics seasonally uninhabitable for large, warm-blooded invertebrates.

       For practical purposes, I do not think these scenarios are relevant in that they would require sustained, high tech exploitation of fossil fuel resources well into the next century - something that may be made economically impossible by global warming, and certainly socially impossible.  I think the upper end of realistic scenarios is well represented by the IPCC's RCP 8.5 scenario out to 2100:

       

       Beyond 2100, we will need to reduce CO2 emissons to zero to avoid the very dangerous tail of the RCP 8.5 scenario.

36316. Tom Curtis at 08:50 AM on 29 May 2014
       John Oliver's viral video: the best climate debate you'll ever see
       

       BojanD @8, if you are rating abstracts, your task is to assign each abstract to one of seven bins (categories).  In doing so, each abstract can only be assigned to one bin; and no assignment can be arbitrary.  These two requirements, together with the guidelines on rating abstracts and the descriptions of the rating levels themselves provide an operational definition of "endorses AGW" and "rejects AGW" for Cook et al.

       Now, suppose you have an abstract that says in part "40 to 45% of the recent (late 20th century) temperature rise is attributable to anthropogenic factors, with natural factors being responsible for 55-60% of that rise".  If we compare the abstract to rating category 7 (rejects with quantification), then we must place this abstract in that bin for it explicitly states, and quantifies, that natural factors are responsible for more than 50% of recent warming.

       According to you, however, we must also place the abstract in bin 2 (explicitly endorses without quantification), for (according to you) "endorsing AGW" means anthropogenic factors are "means [are] a cause and not necessarily the main one", and if they are are the cause of 40-45%  of the recent warming, they are certainly a cause but not the main one.

       That means by your definition, either we must place that abstract in two bins, or the bin we place it in is arbitrary, depending on which bin we compare it to first rather than any particular features of the abstract.  As placing an abstract in two bins is prohibitted, and as rating must be non-arbitrary, it follows that your definition is wrong.  Indeed, the only definition that does not fall foul of the requirement of exclusiveness of rating (only one rating permitted) and non-arbitrariness is a definition that defines "endorses AGW" as endorsing recent warming to be at least 50% caused by anthropogenic factors. 

       In one respect, this more precise definition does not make much difference in that we gain the greater precission of definition only at the cost of a potentially greater error rate in classification.  That is, with the more precise definition, it is more probable that an abstract that should have been rated 4 was rated 3.  However, even if we suppose 50% of all endorsing abstract ratings reported in the paper are in error, and should have been rated 4, that still leave a 96.2% endorsement rate among papers not rated as neutral (compared to 98% reported in Cook et al).  Such a 50% error rate is absurdly high, so whatever the actual error rate, the substantial result of Cook et al stands even with the accurate, precise defenition of "endorses AGW".

36317. mancan18 at 08:24 AM on 29 May 2014
       Rapid climate changes more deadly than asteroid impacts in Earth’s past – study shows.
       

       I like following the Skeptical Science discussions but I'm only a lay person with regard to climate science. I was wondering whether there were any studies that related continental drift and the break up of the supercontinents and shifting of the continental plates around the planet to the excessive volcanic activity that led to these mass extinctions.

       I know that the IPCC do have a climate prediction outcome for business as usual, but has anyone done a maximum emissions outcome if all the known reserves of fossil fuels are consumed. Also, it seems to me that the only analyses regarding emissions is based on current consumption, where great comfort is taken by deniers that there will be 100 to 200 years of coal left to burn. But, this assumes that the developing nations will remain low emitters per capita. What would happen if everyone in the world were emitting per capita the same as the high emitter per capita countries like Australia or the US? Unlike the CO2 doubling debate, perhaps there also needs to be a worst case maximum emission scenario debate, because this would get to the heart of the equity debate. My simplistic analysis of such a scenario indicates that there would only be about 40/50 years of coal left if we consumed at a maximum emissions rate and we would put the CO2 levels back to the time of the dinosaurs in a very short time. I wonder what the predictions regarding the climate and mass extinctions would be in such a scenario.

36318. howardlee at 07:49 AM on 29 May 2014
       Rapid climate changes more deadly than asteroid impacts in Earth’s past – study shows.
       

       Joel and Bill - There have actually been 2 "snowball" episodes, and a number of major ice ages on the planet, long before the most recent Pleistocene ice age.

       About 2.9 billion years ago there was an ice age when microbes evolved methanogenesis, which reduced the CO2 levels in the atmosphere. This was early in Earth's life a time when the sun was less bright than now.

       The first snowball Earth (actually more of a slushball because some areas were not frozen) coincided with the rise of atmospheric oxygen around 2.5 billion years ago. The Earth froze because there had been a lot of methane in the atmosphere, which oxidized on contact with the newly-minted oxygen, removing a greenhouse gas blanket and plunging the planet into a deep freeze in 3 separate ice ages spread over 200 million years.

       The second snowball Earth (the famous one - but even this was more of a slushball) occurred  around 700 million years ago. This was in response to the first greening of land surfaces, which boosted oxygen levels that had been declining since the Great Oxidation Event 2.5 billion years ago. Boosting oxygen once again removed methane that had recovered somewhat as oxygen declined, but more importantly it boosted rock weathering rates which drew down CO2 from the atmosphere. The episode involved at least 3 separate global ice ages, 720-700 million years ago, 650-630 million years ago, and briefly 580 million years ago.

       There was another brief ice age around 517 million years ago known as the MICE event in response to the Cambrian Explosion proliferation of life (and probably enhanced biological pump). 

       There was another major ice age in the Ordovician in response to the rise of vascular plants and the enhanced weathering and carbon drawdown they triggered.

       The ice ages in the Carboniferous-Permian were probably a combination of so much carbon being locked away as coal (CO2 levels down to about 220ppm) and the coincidence of high continental areas at the South Pole. There's some suggestion that an asteroid impact may have tipped the balance to ice age at one point also.

36319. billthefrog at 07:22 AM on 29 May 2014
       Rapid climate changes more deadly than asteroid impacts in Earth’s past – study shows.
       

       @ Joel

       Oops! I discovered the Snowball Earth site a few years back, but hadn't noticed that it had gone inactive. Mea culpa

       NOAA has an interesting palaeoclimatology portal that you might find useful.

       Examples of teaching resources covering this material can be found here and here. 

       A far more detailed description of the first (?) of these events way back in the Palaeoproterozoic Era, the Huronian glaciation, was given in the Proceedings of the National Academy of Sciences.

       Hope that helps.

        

36320. Chris Snow at 07:14 AM on 29 May 2014
       The Wall Street Journal denies the 97% scientific consensus on human-caused global warming
       

       Anything that references the Oregon Petition, which claims that 31,000 scientists deny AGW can safely be dismissed as a load of old tosh.  As you say, anyone with a college degree can sign the petition.  Still, 31,000 sounds a lot until you realise that around a quarter of the US adult population have college degrees. Taking a fairly conservative estimate of 40 million potential signatories since 1998, we get 31,000 / 40,000,000 = 0.0775%. So the 31,000 scientists deny AGW claim is more accurately stated as fewer than 0.0775% of US college graduates since 1998 can be bothered to sign a petition denying AGW, which doesn't sound quite so impressive.

       Regarding the 97% consensus, I reckon that here in the UK it's closer to 100%. I can't actually think of a British climate scientist who is a sceptic. Which is why we often end up with someone like Nigel Lawson in the media arguing the sceptic case.

36321. Alpinist at 06:59 AM on 29 May 2014
       The Wall Street Journal denies the 97% scientific consensus on human-caused global warming
       

       Another stupid WSJ editorial about climate change. What a surprise. Here's something I posted at RC a couple years ago: 

       "Sigh, another day, another stupid WSJ editorial…it’s almost as predictable as high temperature records. You might think that the WSJ would be interested in a fact based reality. You would be wrong."

       Some things just never go out of style.

36322. BojanD at 06:11 AM on 29 May 2014
       John Oliver's viral video: the best climate debate you'll ever see
       

       Not sure I'm following you. I've read the guidelines on rating abstracts and they don't align well with what you're saying here. Just consider that a lot of papers are from the 90s and if the paper from that period explicitly endorses IPCC view (see 3.6), than they endorse the view of the FAR and SAR report and the SAR found discernable influence, not main one. Of course I'm aware that was the state of the climatology of that period, but we're not discussing the evidence here, but the consensus.
       
       I've rated some abstracts myself and there were a lot from the third category implicit endorsement that I've rated as fourth (no position) when the main cause was the issue. If I read "one of the sources of CO(2) and other greenhouse gases (GHG) that influence global climate change", I can't possibly know if this influence is the main one. So Cook et al correctly worded the main findings, but Bedford and Cook didn't, which is surprising, but not that terribly important.

36323. Joel_Huberman at 02:44 AM on 29 May 2014
       Rapid climate changes more deadly than asteroid impacts in Earth’s past – study shows.
       

       @billthefrog - Thanks for letting us know about the interesting Snowball Earth web site. So far as I can tell, though, the last news postings at that site were in 2006. Is there a reason why the site hasn't been kept up? Are there any other sites dealing with the Snowball Earth hypothesis that might provide more current information?

36324. howardlee at 00:13 AM on 29 May 2014
       Rapid climate changes more deadly than asteroid impacts in Earth’s past – study shows.
       

       billthefrog - I think most workers in the field accept the end cretaceous was a "double whammy" - LIP-generated global warming triggering a significant extinction, with the impact dealing a final blow. It's interesting to note that the pendulum is definitely swinging back to emphasize the role of the Deccan Traps LIP as originally highlighted by Gerta Keller.

36325. howardlee at 00:06 AM on 29 May 2014
       Rapid climate changes more deadly than asteroid impacts in Earth’s past – study shows.
       

       Climatelurker - It''s clear that some LIP events have been associated with severe extinctions and others have had more mild extinctions. The Emeishan LIP that occurred just before the Siberian Traps generated global warming and an extinction event much less severe than the Siberian Traps did. 

       That some LIPs have more severe effects on life than others is a puzzle. It probably relates to  eruption rate, presence/absence of organics in the sediments at the LIP location, and other random things. As the authors of one paper noted: "...larger eruptions of flood basalts which clearly had no effect on global ecosystems (e.g. Tarim). The reason why some LIPs are contemporaneous with mass extinctions could be related to random conditions which cannot easily be predicted such as: parental magma composition, geographic location, composition of country rock, or vulnerability of species."

36326. howardlee at 23:49 PM on 28 May 2014
       Rapid climate changes more deadly than asteroid impacts in Earth’s past – study shows.
       

       Villabolo - you are correct for the Kalkarindji LIP - the authors mention oil specifically. In the Permian Siberian Traps LIP it looks like it was mainly coal. In this generalized figure I used "fossil fuels" as a collective noun and to make clear the parallels between the past and today's climate change. In all cases the heat from the magma baked the organic-rich sediments converting them to methane and CO2 (with a host of other nasties mixed in).

36327. billthefrog at 22:28 PM on 28 May 2014
       Rapid climate changes more deadly than asteroid impacts in Earth’s past – study shows.
       

       @ climatelurker

       As scaddenp rightly states, rate of change is absolutely critical in terms of extinction potential. In the case of both bolides and mega-volcanism, there is a double whammy. The initial spectacular aerosol cooling is likely to be pretty short-lived, as these particles will not have a long atmospheric residence time. On the otherhand, so-called greenhouse gases have this habit of lingering on, and on, and on...

       One of the fingerprints of massive CO2 build up is the presence of cap carbonate deposits, as discussed in this piece from the Snowball Earth site. 

       Also, the following from the BBC describing some of the dramatic events on the planet's timeline might be of more than passing interest. Scroll down to the bottom of that screen and there are links to various extinction theories (incl climate change) as well as the varying habitats that would have been extant at different times.

       Incidentally, I've just noticed that one of the scientists appearing in the BBC video clips (Paul Hoffman, from the Earth and Planetary Sciences Dept at Harvard) is also involved with the Snowball Earth project.

36328. BC at 13:54 PM on 28 May 2014
       2014 SkS Weekly Digest #21
       

       I couldn't access the first link under El Nino Watch

       Moderator Response:

       [PS] I notice that it is not actually a link. Till author fixes it, try this:

       "How El Niño Might Alter the Political Climate"

       [JH] The link has been inserted into the OP. Thank you for bringing this glitch to my attention.

36329. DSL at 13:28 PM on 28 May 2014
       Antarctica is gaining ice
       

       Anthony, check out the sea level rise explorers here and here to see what a few meters or a few dozen meters of SLR mean for agricultural and infrastructural destruction, and population displacement. 

36330. Daniel Bailey at 13:00 PM on 28 May 2014
       Antarctica is gaining ice
       

       http://pubs.usgs.gov/fs/fs2-00/

       

36331. michael sweet at 12:10 PM on 28 May 2014
       Antarctica is gaining ice
       

       Anthony,

       This SkS thread says tht if Geenland melted it would raise sea level 6 meters.  You would expect at least the same amount from Antarctica.  Here in Florida a 12 meter sea level rise would inundate 3/4 of the state, home to about 15 million people.  Bangladesh would be long gone.  That seems like a lot to me. How much is a lot to you?

36332. Charliec65 at 07:43 AM on 28 May 2014
       Looking for connections
       

       I agree with placing the growth of the human population into the essay.  We're living in a "life bubble" much like our recent financial bubble.  We unfortunately don't have a central bank to come to the rescue.  The correction will likely be as hard as the beneficial rise as we've experienced over the past 300 years.

       Broadly living processes have little capability to control their growth rates.  There isn't one life form that fails to over-exploit its environment.  We have been shaped by evolution to reproduce, expand into environments, and wage war from verbal to physical when necessary or possible to sustain our groups.  Humans like to think of themselves as separated from nature by nurture, but that's a tenuous connection in the best of times.

36333. scaddenp at 07:29 AM on 28 May 2014
       Rapid climate changes more deadly than asteroid impacts in Earth’s past – study shows.
       

       climatelurker - what is important is the rate of change. A rapid change over 3C may have more effect than a very slow change over say 6C. The initial cooling by aerosols and then rapid warming by GHG are probably both important. I think the most useful numbers would be rate of change in forcing (W/m2/century) which is much more informative than % concentration. However, for paleoevents, it is very difficult to get high precision both dating and forcing. CO2 is only indirectly measured by change in a proxy for pH which in itself must have a large time-constant for ocean mixing. Estimating the forcing from aerosols on a volcanic eruption that has never been observed is even more complex. We struggle to measure aerosols even today.

36334. villabolo at 06:09 AM on 28 May 2014
       Rapid climate changes more deadly than asteroid impacts in Earth’s past – study shows.
       

       On the volcanic diagram, in the white box at the lower left, it says "fossil fuels". Shouldn't that read fossil oil instead? It became a fuel from our modern persapective.

       Moderator Response:

       [JH] Nope. Natural gas is a fossil fuel. It is not fossil oil. 

36335. climatelurker at 05:33 AM on 28 May 2014
       Rapid climate changes more deadly than asteroid impacts in Earth’s past – study shows.
       

       I'm curious what the differential is between pre and post extinction events, if there's a threshold beyond which massive die-off's are (or appear to be) set in motion.  Maybe as a percentage of current atmospheric levels, or an absolute change?  I've seen there are links to how fast the changes occur, but how much isn't clear (at least not to me).  Would love to see an article about CO2 levels at different times, and what they were before and after these events.  I imagine such a discussion would have to take into account feedbacks and absorption saturations, et cetera... I can hear the deniers already, "CO2 is already almost saturated!  Adding more won't do anything!"

36336. Anthony10658 at 05:24 AM on 28 May 2014
       Antarctica is gaining ice
       

       The Vice news program on HBO had an interesting story of how the Glacial land ice is melting in Greenland at a rapid rate. If Greenland becomes green, and all the land ice melts, can we really expect the sea level to rise by that much?

36337. Anthony10658 at 05:20 AM on 28 May 2014
       Animals and plants can adapt
       

       Speaking of migrations, over the past few years, there has been a increase of Canadian Geese who have taken up permanent residence in the San Francisco South Bay Area. The strange part about it is that the weather here is actually warm, not cold. The birds used to be seen here for the winter months, now they are here all year round, hanging at public parks, golf courses, and school fields.

36338. billthefrog at 04:07 AM on 28 May 2014
       Rapid climate changes more deadly than asteroid impacts in Earth’s past – study shows.
       

       In 2013, the eminent palaeontologist, Steven Stanley was bestowed the Penrose Medal, the top honour awarded by the Geological Society of America. Prof Stanley has long been a proponent of the idea of punctuated evolution, as opposed to the classical, more gradual evolutionary pressures first suggested by Darwin and Wallace.

       Stanley's proposed mechanism for these evolutionary spurts is by extinctions (mass and otherwise) either freeing up niches or increasing the competion therein. His suggested mechanism for these extinction events? You guessed it - climate change. Interestingly, Stanley feels that climate change in either direction can be equally efficacious as an extinction mechanism.

       Being a thicko engineer, I never covered any of this stuff during either of my degrees. I only have a vague grasp through a general interest in science and wanting to learn more about our planet's history. (And hence getting some insight into its future.)

       The OP mentions that "most scientists agree a giant asteroid impact wiped out the dinosaurs". This is obviously out of my field, but I had discussed the K/T (I'll never get used to calling it the K/Pg) on many occasions with one of my neighbours - sadly no longer with us. The gentleman in question however, was a Fellow of the Geological Society of London and was keen to disabuse me of the idea that this was a settled issue.

       According to Myles, there were (are?) two diametrically opposed camps in the debate. (Sound familar?) There are those who are convinced by the arguments put forward by the Alvarez/Alvarez/Asaro/Michel camp relating to the Chicxulub bolide as the Deus ex Machina. However, as indeed mentioned in the OP, others look towards the massive basaltic eruptions that spewed forth from the Deccan Traps.

       By amazing coincidence, my current bedtime reading is a book called "The Sixth Extinction", by Richard Leakey and Roger Lewin. They also view climate change as a very likely vector for the many of the extinctions the planet has experienced - and continues to experience to this day.

36339. WheelsOC at 02:36 AM on 28 May 2014
       Rapid climate changes more deadly than asteroid impacts in Earth’s past – study shows.
       

       A couple of years ago there was a paper that compared modern rates of CO2 emissions/ocean acidification to geologically significant changes and mass extinction events over the last ~300 million years. It turns out that even The Great Dying happened with atmospheric CO2 increasing at rates 1-2 orders of magnitude slower than what we're causing today. 

       The paper is here (paywalled), and there's a good write-up summarizing it here.

36340. Rob Honeycutt at 01:22 AM on 28 May 2014
       Sea level rise due to floating ice?
       

       This whole discussion is perfect example of what seems to go on with climate change denial, on a larger level. 

       One side is trying to point out how the science works. The other side starts with a presumption of fact, rejects known physics, does incorrect experiments/analysis, claims those doing the science are politically motivated when the results conflict with their expected outcomes, and in the end storms off unable to process the fact that they are wrong on the science.

       It's hard to be the person proven wrong. It takes a strong person to look at evidence and admit an error. All too often I see people double down on their error and run away rather than facing hard facts, as thorconstr has done.

       Moderator Response:

       [Dikran Marsupial] Please can we restrict the discussion to the science.

36341. Tom Curtis at 01:03 AM on 28 May 2014
       John Oliver's viral video: the best climate debate you'll ever see
       

       BojanD @6, a paper assessed as reporting that 45% of global warming was anthropogenic, with the rest being natural would have been rated as rejecting the consensus on global warming.  That is made explicit by rating category 7.  As categories 5-7 do not differ on whether they endorse or reject the consensus, but only the quality of the evidence as to whether they endorse or reject the consensus, what applies to category 7 also applies to categories 5 and 6.  Similar reasoning applies in reverse for endorsement.  Consequently, I do not think it was Bedford and Cook who made the mistake in this instance.

36342. BojanD at 00:47 AM on 28 May 2014
       John Oliver's viral video: the best climate debate you'll ever see
       

       @localis, you're right, it won't do anything to change the denier's attitude. Recently I was involved in a discussion where somebody proudly proclaimed that Bedford & Cook were wrong in asserting that Cook et al. found 97% consensus that humans were the main cause. I agree, since it found 'only' the consensus on AGW (which means they are a cause and not necessarily the main one), but this person blew this lapse out of proportion. It was a typical penny-wise, pound-foolish attitude that you encounter in individuals that pretend to introduce rationality in the discourse.
       
       It makes me wonder, however, how Bedford & Cook could make such an obvious mistake.

36343. wili at 00:05 AM on 28 May 2014
       2014 SkS Weekly Digest #21
       

       Thanks for the highlights. If I may be so bold, it would be great to have an update on slr estimates in light of the recent news about GIS and WAIS melt dynamics. What do these studies mean for long and short term melt rates. The MSM coverage seems to include estimates that seem to go far beyond what the science is saying and estimates that seem far to conservative given, especially given the recent developments. ANy clarification you folks could throw on this jumble about these important issues would be greatly appreciated.

36344. John Hartz at 21:57 PM on 27 May 2014
       Sea level rise due to floating ice?
       

       Could it be that thorconstr's ultimate goal was to provke regular SkS commenters in order to "proove" that SkS is ideologically biased? If so, the ice-in-glass-of-water "experiment" was just a ruse.

36345. Tom Curtis at 21:34 PM on 27 May 2014
       Sea level rise due to floating ice?
       

       chriskoz @53, thanks for picking up, and correcting the errors.

36346. chriskoz at 20:54 PM on 27 May 2014
       2014 SkS Weekly News Roundup #21B
       

       wili@1,

       Usually, Al Jazeera reports quite accurate and complete climate science news but this time, i'm a bit disappointed because your link does not provide good info, not even a pointer to the study itself... I found somewhat better report in SA here, with the link to the actual study therein.

       I don't have access to the study so I cannot be sure what it is about. But I suspect they talk only about the topography of Greenland coastal rockbed, as reported in SA. I.e.: the volume of fjords below sea-level, currently filled with ice, is 3 times bigger than assumed in current iceflow models. Likely they don't make any inference about how much iceflow model output changes if the model bedrock topography is altered accordingly. So we need to wait for that conclusion.

36347. chriskoz at 19:19 PM on 27 May 2014
       Sea level rise due to floating ice?
       

       Tom@47,

       the ice in fresh water ill have only 0.042 m^3 above the surface, but 0.044[0.054] m^3 above the surface if floating in fresh [salt] water[...] 0.002 m^2 more volume than it displaced in sea water

       You made a slight arithmetic mistake, corrected above. Consequenttly, the difference in displaced water is: 0.458 - 0.446 = 0.012m^2 (rather than your incorrect 0.002 m^2 result). So, after that correction we conclude that the perceived increase of volume of seawater (dV) in your setup increased by 0.8% (0.012m^3 out of 1.446m^3).

       So, in Thor's setup, where the proportion of ice is much less, say some 50ml in 250ml (he didn't give me the number because he wants to discuss his rhetorics rather than science), I estimate dV would be some 3-4 times smaller (per my quess of his proportions), therefore dV in his experiment was some 0.3%, which translates to dh of 0.3mm over 10cm high glass. Or even less: some 0.2mm, because his glass has signifficantly higher crosss section where dh is measured.

       In conclusion, such small dh (0.2mm) is undistinguishable by eye and within the menisk shape uncertainty, as pointed earlier by DM. Therefore, Thor's experiment cannot be used to confirm this simple science herein. We know, that Thor set it up not for confirming science but for his baseless rhetorics.

       On the other hand, an original experiment as setup by MartinS confirms the science: I estimate his dh should be about 1mm (because the ice chunk proportion looks as big as Toms') which looks about right on his picture.

36348. Tom Curtis at 19:16 PM on 27 May 2014
       Sea level rise due to floating ice?
       

       Thankyou Dikran, for reminding me of thorcontr's empty challenge about blowing up the images to show the lips of the glass:

       

       H-res version here.

       Close examination on the left of the glass shows the water level not up to the lip in either photo, ie, either with ice present (upper image) of melted (lower image).  If, however, you look to the right hand side (under the yellow arrows), in the upper image the inside of the lip is clearly visible.  In constrast, in the lower image the lip is obscured from vision by the meniscus.  Clearly the meniscus must have risen higher than the lip to obscure it from vision, and hence has shown an increase in level.  Indeed, the difference in camera angles tends to obscure this fact.

       Clearly the surface of the glass slopes downward from left to right, resulting in the meniscus being above the lip on the right, but below it on the left.  Also, if you look closely, this is obscured in the first image by the surface of an ice cube partially concealing the lip on the left, giving an apparent slope in the other direction to casual observation.

36349. Dikran Marsupial at 19:04 PM on 27 May 2014
       Sea level rise due to floating ice?
       

       Just to add, Wikipedia has a nice brief explanation about how liquid volumes should be measured to take the meniscus into account.  Note in particular observations should be made with the top of the liquid at eye level to avoid parallax errors.  Compare this with MatrinS's experiment and with thorconstr's.  I knew this already because I did chemistry at school.  It is alright not to know this, but it is not alright to repeatedly ignore this sort of knowledge when problems with experiments are pointed out to you by those who do.

36350. Dikran Marsupial at 18:35 PM on 27 May 2014
       Sea level rise due to floating ice?
       

       thorconstr wrote "I can't believe you ask this, no matter what the surface, when things rub they cause friction which would affect the experiment."

       O.K. so the question is how much friction would there be, and would it be enough to materially affect the outcome of the experiment.  I would say that the friction involved would be negligible as ice and glass, both lubricated by a film of water,  are both extremely slippery materials. Note that as the ice is melting there won't be much of a connection between the solid surfaces as the surface of the ice will be constantly melting.  Note the reason that ice skating is possible is that a thin film of water removes what little friction there was between the ice and the blade of the skate.

       "Everyone here accepted the first experiment without question, the experiment is far from professional yet you accept it like the "Holy Grail", "

       This is hyperbole.  It is a simple experiment that verifies something we already know from very basic theory (as Tom pointed out to you).  If you get the science right, you don't need this sort of rhetoric.

       "Mine wasn't intended as a professional experiment."

       neither was MartinS's, I suspect, and yet you chose to question the honesty of his experiment, when it was actually performed rather more professionally than yours - at least the meniscus could be measured properly in his.

       " If I found that I was wrong I would have said so. "

       We try running the experiment again, using the suggestions I gave.

       "If I blow the pictures up to show only the glass rim the water level is the same, whether you believe it or not."

       How many times do I have to say that you can't accurately measure the meniscus this way by eye.  Blowing up the pictures doesn't change this fact.

       "In retrospect, posting on a such a totally left leaning sight was a mistake."

       Physics is independent of political orientation.  Try doing the experiment properly.

        

Prev  719  720  721  722  723  724  725  726  727  728  729  730  731  732  733  734  Next