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BBD at 03:00 AM on 14 July 2011A Detailed Look at Renewable Baseload Energy
KRFor some reason the difference between max capacity and average power keeps coming up in skeptical arguments against renewable power...
Ah. Now that I can help with. Certainly as regards the UK. The problem is that renewables manufacturers and the government have a naughty habit of quoting capacity rather than average output when talking up the latest wind project. -
DSL at 02:48 AM on 14 July 2011Trenberth on Tracking Earth’s energy: A key to climate variability and change
CO2isnotevil, the problem has always been that "skeptical" arguments are not consistent with anything else. No alternative theory has been brought forth that accounts for the physics and the data. At best, "skepticism" as you define it is just a series of attacks launched from no theoretical position and designed to get rid of the narrative that the reality of GW forces (it is us and it is bad) but not at all establish a more accurate, socially-produced scientific understanding of climate. In other words, you don't care about the science; you care about managing the spin--hence the nature of your comment.Moderator Response: [Dikran Marsupial] Please keep the discussion impersonal and on the science. As they say "don't wrestle a pig, you both get dirty, but the pig likes it"; if you think someone is not engaging in scientific discussion, the best policy is to simply ignore them. -
RyanStarr at 02:16 AM on 14 July 2011Visions of the Arctic
I suppose it begs the question (modern usage), how much warming can a polar bear?Moderator Response: [Dikran Marsupial] "warming" added -
KR at 02:02 AM on 14 July 2011What we know and what we don't know
I would suggest taking the (off topic) discussion on CO2 growth rates to the An exponential increase in CO2 will result in a linear increase in temperature thread. Or better yet, Eric the Red, go discuss this with Tamino, who has rigorously shown the greater than exponential growth of CO2. -
co2isnotevil at 01:53 AM on 14 July 2011Trenberth on Tracking Earth’s energy: A key to climate variability and change
Ken, [Moderation complaint deleted] BTW, it's my understanding that Trenberth is traveling around AU/NZ and will return on the 21'st. GModerator Response: [Dikran Marsupial] Posts containing complaints about moderation are normally deleted (after reading), so it is a bad idea to mix such complaints with any other comment you want to make as that will get deleted as well. I have edited your post, rather than deleting it, on this occasion to make sure you understand the situation. -
Eric the Red at 01:40 AM on 14 July 2011What we know and what we don't know
Kevin, Tom is correct in that I am not misreading the graph. If the CO2 increase was exponential, the rate of increase (Tom @16) would show a linear rise. Since 1900, atmospheric CO2 showed a near linear rise until WWII, then an exponential rise. As shown in @8 and @16, the rate of increase is decelerating. In an exponential, it would be constant, and if it were faster than exponential, it should be accelerating. I am not discounting Tom's analysis, as it may accurately portray the causes. However, the increase started deviating from an exponential growth in the 1960s, and is approaching a linear increase (has been linear for the past 13 years). In fact, had we continued growing exponentially, the rate of increase would be over 3ppm/yr, not the 2 that we have measured recently. The exponential growth was during a time of exponentially rising population and economic growth. Neither of these appear to be happening today. -
chris at 01:30 AM on 14 July 2011Visions of the Arctic
Eric the Red at 23:43 PM on 13 July, 2011 Eric, the evidence indicates otherwise. Surprising as it may seem global biodiversity as indicated by the fossil record is inversely related to temperature; i.e. greater biodiversity during cooler periods and lower during warmer. PJ Mayhew et al. (2007) A long-term association between global temperature and biodiversity, origination and extinction in the fossil record Proceedings of The Royal Society B 275, 47–53 abstract Of course the huge rate of warming that we are experiencing now and still to come is bound to lead to considerable species loss, compounded by habitat degradation and loss, and that's of greater concern (the very rapid warming) than a warm climate per se. -
KR at 01:20 AM on 14 July 2011A Detailed Look at Renewable Baseload Energy
In my previous post about Waldpolenz Solar Park and long term density, I did not actually show my calculation of the instantaneous power density. I wanted to show that as well for completeness. Waldpolenz occupies 110 hectares, and generates ~40,000 MWh per year. Conversion efficiency is irrelevant for this calculation. That's 4*10^10 Wh/year, divided by (24*365 hours), divided by 1.1*10^6 m^2, giving an average power density of 4.15 W/m^2, with correct units. This agrees with Smil's estimate of 4 W/m^2. Note that instantaneous power for a PV system like this will of course vary from summer noon maximum to nighttime zero - the rated capacity of the plant must be able to handle the summer noon maxima. This is one reason that the rated capacities of solar and wind power plants are so much higher than the average power produced. For some reason the difference between max capacity and average power keeps coming up in skeptical arguments against renewable power... Adding tracking to this fixed panel system would likely increase both average power density and effective collection of available sunlight by ~60%, without changing maximum capacity (through more time spent near maximum), albeit at a significant cost in initial build and maintenance. -
KR at 00:45 AM on 14 July 2011A Detailed Look at Renewable Baseload Energy
BBD - The ~230 Wh/m^2 average is taken directly from MacKay, and is a quite conservative estimate of tropical year round 24hr averages. The peak on his table is 273 Wh/m^2 in Nouakchott, MR. This refers to sunlight available prior to conversion into usable power. The 200 W/m^2 (note the different units - W/m^2 vs. Wh/m^2) came from peak insolation of 1000 W/m^2 and a 20% conversion efficiency - instantaneous converted power at noon, not time averages of sunlight. Apples and oranges. Wh/m^2 and W/m^2 are not equivalent, despite confusingly similar numbers. I always have to double check what I'm working with... -
DSL at 00:14 AM on 14 July 2011OA not OK part 5: Reservoir dogs
Meat - eating meat - a movement of carbon between reservoirs that are in an original figure (an animal that has organically grown (originated) the meat?) - resulting in fluxes - bloody flux? - uncooked meat? The Vegan in me is weeping quietly in a dark corner, Riccardo. -
Tom Curtis at 00:11 AM on 14 July 2011What we know and what we don't know
kevin s, I greatly appreciate the sentiment and comments, but let me assure you that Eric the Red is one of the regular cast of characters here, and is very unlikely to be misreading the graph in the way you suggest. -
Tom Curtis at 00:07 AM on 14 July 2011Visions of the Arctic
Eric the Red @29, that is a simplistic response. Life adapts to the conditions it is in, and when those conditions change, some species find themselves ill adapted to the new conditions and go extinct. That is part of the reason the end of the last glacial saw an extinction pulse, and why the PETM and the end Permian warming resulted in massive extinctions. Indeed, the end Permian extinction was the greatest extinction known in 600 million years. A shift from cold, relatively dry conditions to warm moist conditions, therefore, is likely to result in an extinction pulse. That in five to ten million years life will adapt and there will be more species, and more biomass on the planet will not change that. Further, unlike the events in the PETM and Permian extinction, on this occasion species around the world are already massively stressed from habitat loss and over exploitation. That means life has few resources with which to survive a significant environmental change. -
DSL at 00:04 AM on 14 July 2011Visions of the Arctic
Ken, you can't calculate the odds of evolution like that--even with very gradual changes. It all depends on the type of change. For example, if a snowball Earth gradually develops, will 50% of species benefit? No. If an mile-wide asteroid strikes the Earth, will 50% of species benefit? No. If gradual warming (3C over 40k y) occurs, will 50% of species benefit? Possibly. If rapid warming occurs, will 50% of species benefit? Maybe, but you'd damned well better have a studied reason for thinking so (and express it), because rapid change rarely benefits elements in a complex, integrated, dynamic biological system. Even elements that benefit in the short term in such conditions might be doing so at the (unfortunately necessary) cost of their long term survival. Your statement is evidence of poor thinking, Ken. In fact, it seems only to serve a need to be contrary. While I might agree that there might be a need to point out these "Natural World 101" type ideas for the sake of lurking doubters, in this case I think it's a complete waste of time. -
kevin s at 23:59 PM on 13 July 2011What we know and what we don't know
This succinct summary is useful...the more succinct the better, I find, because in face-to-face conversations, people taking the so-called "skeptic" position often change the topic frequently. This type of info seems to be best suited for people who are willing to modify their opinions in light of established facts. But as we know, not everyone is like that. I'm not sure what the proper approach is to those who aren't. But I think it's best to extend people the benefit of the doubt for as long as possible. For example, ETR's assertion that looking at all the data, CO2 rise is decelerating may seem like an unwillingness to accepts the facts plainly presented. But I wonder if perhaps he is reading the graphs of rate of CO2 increase presented here as graphs of CO2 level (instead of rate of increase). In that case graphs like the one from Tamino that Tom presents @ 16 would indeed *look* like there was a deceleration, and ETR would think *we* are the ones in denial. But of course, it is in fact a graph of *rate* of increase, and any curvature is not acceleration but acceleration of acceleration (or "jerk"). I think extending the benefit of the doubt feels better and has a better impact on lurkers than branding someone a denialist...even if they probably are. And I choose to believe that ETR is misreading the y-axis but being otherwise reasonable. Mods, I realize that most of this crosses into territory that's been declared off-topic, and I certainly won't be offended if this comment is deleted because of that. I just thought it was worth noting that in this particular case, what looks at a glance like trolling could be an honest mistake. I don't participate here often, so I don't really know the cast of regular characters.... -
Eric the Red at 23:43 PM on 13 July 2011Visions of the Arctic
Ken, Historically, life has benefited more from warmer than cooler climates. Plant life becomes more abundant due to the longer growing season and greater precipitation. Animal life benefits from greater plant life, and milder winters. That is not to say that there are not those who come out on the short end due to competition and changing environments. Recently, the growth of the human population has influenced other life on this planet much more than any factor since the end of the last ice age. -
Tom Curtis at 23:38 PM on 13 July 2011Neptune is warming
Dikran Marsupial @5, I suspect Svenmark would have a hard time applying his theory to Neptune as well. Is he some how going to increase Neptune's 100% cloud cover?Moderator Response: [Dikran Marsupial] Good point! ;o) -
Eric the Red at 23:36 PM on 13 July 2011The Medieval Warm(ish) Period In Pictures
Sea level is a bit trickier to ascertain as local levels may change much more dramatically than global levels, with causes unrelated to global changes. However, here are a few examples regarding to sea level during the MWP: http://people.rses.anu.edu.au/lambeck_k/pdf/237.pdf http://www.sciencemag.org/content/150/3700/1165.abstract -
Riccardo at 23:36 PM on 13 July 2011OA not OK part 5: Reservoir dogs
"In the next series of posts we will discuss the movement of carbon between each reservoir (fluxes) that are in the original figure" Here's where the meat is :) -
ocelote at 23:35 PM on 13 July 2011It's cooling
The gulf stream might be changed because of the salt concentration decreasing due to ice melting in poles. This stream is supposed to bring heat from tropics. I wonder `how strong this effect will be for the European coasts... -
Dikran Marsupial at 23:31 PM on 13 July 2011Neptune is warming
Thebadmentor@4 Can you suggest another forcing that affects both Neptune and the Earth. This article is a counter-argument to the suggestion that solar focing is responsible for climate change on Earth as it is also causing climate change on Neptune (except it isn't). It is the skeptics that seem to think only TSI affects planetary climate ("its the sun"). P.S. Yes, I do know about Svensmark's cosmic ray theory as well, but you would have a hard time applying that argument to Mars, which is also used as an example in such arguments. -
Composer99 at 23:28 PM on 13 July 2011OA not OK part 5: Reservoir dogs
Correct me if I am wrong; but it appears to me that the caption underneath the diagram showing carbon reservoirs explains the blue and red circles. -
Byron Smith at 23:28 PM on 13 July 2011OA not OK part 5: Reservoir dogs
ianash - Hope I'm not explaining things that are bleedingly obvious to you here. The diagram (Figure 2) does take a little effort to understand. It is divided schematically into five fields, representing the five main reservoirs of carbon in the global carbon cycle. As stated in the caption, the size of the blue circle represents the mass of carbon in each reservoir in pre-industrial times, while the red circle shows the mass of carbon in the mid-1990s (as noted in the post, things have changed quite a bit since then. Could someone put up some updated numbers? Even an approximation would help.) For some reason, unexploited fossil fuels are shown in a single black dotted circle rather than red and blue ones. In each field, the black circle indicates the scale of change from pre-industrial to mid-1990s. If the black circle appears in a blue circle (as it does for atmosphere and both surface and deep oceans), that reservoir has gained carbon. Soils and plants has a black circle in the red sphere, indicating a loss of carbon (think deforestation, though also other processes). The fossil fuel circle indicates the relative scale of estimated recoverable reserves vs total amount of fossil fuels extracted and exploited (i.e. less than 7%), making the point that there is still plenty of carbon we could potentially dig up and stick in places where its going to mess things around (i.e. the atmosphere and oceans). Numbers give the Gt of carbon represented by each circle and then the % change. (Some have criticised the IPCC's figures for being considerably too rosy about the total reservoir of recoverable carbon from fossil fuels, but even less optimistic figures still give us plenty of scope to keep making more mess.) So the quick take-away message from the figure is that between the industrial revolution and the mid-1990s, we took 283 Gt of carbon from places where it wasn't doing anything particularly bad for us and put it into places where it is.Moderator Response: I should have said: Previous unclear caption was edited. Doug -
Thebadmentor at 23:23 PM on 13 July 2011Neptune is warming
TSI is your argument? Do you really think that its only TSI that affects Plantes Climate? WOW! -
Doug Mackie at 23:02 PM on 13 July 2011OA not OK part 4: The f-word: pH
@DLB From someone who reads recent scientific papers that is a surprising question. What makes you think the dissociation of water would change? -
Ken Lambert at 22:40 PM on 13 July 2011Visions of the Arctic
I have never read a piece by an environmentalist which did not pose a dire warning of some kind about the imminent demise of some form of wildlife. Surely the odds are that some creature somewhere will benefit from a warmer world. In fact the odds are probably even that 50% of creatures will benefit and 50% won't.Moderator Response: [Dikran Marsupial] The odds are almost certainly not 50-50. Most organisms will have adapted to a particular ecological niche, and so any change is likely to mean they are sub-optimally adapted for their conditions. Of course there will be winners and loosers, but the theory of evolution would suggest there will be more loosers than winners, at least in the short-medium term. -
Eric (skeptic) at 22:36 PM on 13 July 2011Trenberth on Tracking Earth’s energy: A key to climate variability and change
Rob #35, if the weather causes a 0.1 or 0.2 rise or fall in GAT in less than a week (although this only happens a few times a year), it is probably one of the more random effects of weather (using a precise definition of random). For this to happen, with either outcome cooling or warming, a lot of weather systems have to complement in both hemispheres which are, for the most part uncoupled. Getting both hemispheres to line up on a short time scale is thus pure chance. Getting a single hemisphere to align in warming or cooling is a little less random due to teleconnections, but those are limited in scope and generally peristent through a season. The topic certainly merits a lot more research. -
Eric the Red at 22:35 PM on 13 July 2011The Medieval Warm(ish) Period In Pictures
scaddenp, You were requesting information on glacial retreat. The first in from Schnidejoch in Central Europe, the second is from Glacier National Park in Montana, and the third is from the Greenland ice cores. http://www.giub.unibe.ch/klimet/docs/climdyn_2007_grosjean_et_al.pdf https://www.cfa.harvard.edu/~wsoon/RajeshKoushik10-d/MacGregoretal10-12900yrSwiftcurrentLakeGlacierNatlPark.pdf ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/gisp2/isotopes/gisp2_temp_accum_alley2000.txt -
Ken Lambert at 22:21 PM on 13 July 2011Trenberth on Tracking Earth’s energy: A key to climate variability and change
Moderator - Daniel Bailey Do we have any indicaton that Dr Trenberth will participate in discussions on this thread? There are a number of questions which merit some response (and a few which do not), so if there is no one arguing Dr Trenberth's case (chiefly himself) - this thread will wither on the vine.Response:[DB] My understanding was that Dr. Trenberth was travelling abroad for a few weeks. As a service, he provided this article before he left. Given his busy schedule, I would be (happily) surprised if he were able to make an appearance before then.
That being said, perhaps few feel the need to prosecute the case so eloquently presented by an expert, such as Dr. Trenberth?
In any event, questions remaining unanswered should be addressed in a future iteration of this article, so tack any of them up here for posterity. Few threads here at SkS are truly "withered"; many are inactive, but witness the undead 2nd law thread...
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Eric (skeptic) at 22:21 PM on 13 July 2011Polar bear numbers are increasing
Thanks very much for the update (30 September 2010) on this older post. I just noticed it now and it is much improved in context over the original. -
ianash at 21:58 PM on 13 July 2011OA not OK part 5: Reservoir dogs
I'm not trying to be funny - the diagram just makes no sense to me - sorry for not being substantive enough for you. -
CBDunkerson at 21:49 PM on 13 July 2011Visions of the Arctic
The writeup on the Davis Strait population says: "Ecological covariates associated with survival suggest that the decline may be as a combined result of short-term and local density dependence, stabilization of harp seal (Pagophilus groenlandicus) numbers and declining ice conditions." Ergo, I wouldn't agree with the statement that this was due to hunting. That leaves only three populations (Baffin, Kane, and Lancaster) which are declining primarily due to hunting. The Chukchi Sea population is declining due to both ice loss and illegal hunting, but it isn't clear how much of the decline is due to each factor. -
Tom Curtis at 21:48 PM on 13 July 2011Seawater Equilibria
Further reflection on Eby et al suggests that if we were to stop all emissions instantaneously, CO2 levels would fall to about 315 ppmv after 10 thousand years, but take 50 to 100 years to fall to 350 ppmv. That is, of course, irrelevant. The only target we have a realistic hope of achieving at the moment, and only if we act decisively in the next few years is around 450 ppmv, locking in a 2 degree temperature increase that is likely to last for a century or so, and take over three thousand years to fall back below 1.6 degrees C. -
Tom Curtis at 21:38 PM on 13 July 2011Seawater Equilibria
Eric (skeptic) @91, you may find Eby et al, 2009 more useful than Archer and Brovkin, 2006. They examine the impacts of both smaller, and a wider range of CO2 slugs than to Archer and Brovkin. In particular they examine the impact of a slug of 160 Pg on top of 2000 levels of CO2 in the atmosphere (estimated at around 300 Pg). The slug of CO2 adds an additional 69 ppmv of CO2 to 2000 levels. This slug then decays exponentially so that its contribution to the atmosphere is just 41% of the original after 50 years (34.5 ppmv), just 37% after 100 years (25.5 ppmv), just 35% after 150 years (24.2 ppmv), and 27% after 200 years (18.6 ppmv). After a thousand years it declines to 23% (15.9 ppmv), and after 10 thousand, to about 18% (12.42). These decay rates are an overestimate of expected decay rates for stopping all emissions now. That is because if the CO2 is introduced slowly rather than as a single slug in one year, it has time for some of it to reach enter the deep ocean before emissions cease. Consequently the initial peak of atmospheric CO2 concentration is not as high, but the decay rate from that peak is slower. For example, in the 160-A2+ model run conducted by Ebi et al, peak atmospheric CO2 was just 37.7% of that in the 160 model run. In the 160-A2+ run, CO2 was introduced over several centuries, and the decay pattern follows a similar path to the 160 run from the point where that run decays to 40% of the peak. As it happens, Eby et al ran a control experiment with no emissions after 2000. The result was that after ten thousand years, the CO2 concentration dropped by 55 ppmv from a peak of 376 ppmv. That represents a fall to 33% of the peak increase after ten thousand years. It also suggests that after 150 years of exponentially increasing emissions, 16% of CO2 that would otherwise be stored in the atmosphere has been stored in the deep ocean. -
Eric the Red at 21:36 PM on 13 July 2011Visions of the Arctic
Eric, Recent polar bear populations have been so strongly influenced by hunting that other influences are lost in the noise. There is little doubt that the Oslo agreement has been responsible for an increase in polar bear populations worldwide over the past several decades. Actual values for this increase are open to speculation as early data was difficult to obtain. Even recent numbers are somewhat speculative. Restricting hunting to natives in the affected areas may have resulted in population changes to certain areas (Hudson Bay) that are not representative of the whole. Increases in human populations in these areas have probably been a much larger factor than any other. Recent calls for lifting the ban on polar bear hunting will undoubtedly effect their numbers. Discerning the effects of climate change in relation to hunting is very difficult. -
Eric (skeptic) at 21:31 PM on 13 July 2011Visions of the Arctic
CBDunkerson, I appreciate your well-founded replies to me over the past year. The table that is linked in the post (link above) shows that "most declines due to hunting except Hudson Bay" is well-supported with a modification. There are 6 populations with risk of future decline evaluated at "very high": Baffin Bay, Davis Strait, Kane Basin, Norwegian Bay and the 2 Hudson Bay populations. The first three are declning due to hunting, and the latter three have declining body condition. One other population, Lancaster Sound is listed as "higher" risk of decline, due to hunting. Southern Beaufort Sea is at moderate risk of decline due to declining sea ice. Two populations have very low risk of decline, and the rest have insufficient data (e.g. Russian populations with substantial hunting). I would recommend that people click on each population and read the text. -
CBDunkerson at 21:04 PM on 13 July 2011Visions of the Arctic
'Other marine mammals not impacted': Actually, one of the threats to polar bears from global warming is the danger it poses to their food sources. Ringed and Bearded seals are the primary prey of polar bears... but they den on the ice. As ice melt has accelerated it has become common for newborn pups to have their den melt around them before they are capable of surviving in the water. In the U.S. the conservation status of both species is currently under review to see if they should be listed under the Endangered Species Act. 'Most polar bear population declines are only due to hunting': Eric, as we've discussed before, that isn't supported by the evidence. People wishing to get the real story can do so at the IUCN polar bear status page. The links to each sub-population on that page give information about the causes of population declines... and the claim that it is over-hunting for every group except the Hudson Bay population is just false. -
Arkadiusz Semczyszak at 21:02 PM on 13 July 2011Trenberth on Tracking Earth’s energy: A key to climate variability and change
@Rob Honeycutt Aerosols are mainly India + Pakistan and others are rapidly developing poor countries of Africa and Asia (the use of simple reserves) - not China. I do not “believe” in “... that some unknown systematic error in the Argo float system is causing the flattening ...”. Recently I analyze an interesting paper The HadGEM2-ES implementation of CMIP5 centennial simulations, Jones et al. 2011. (36 coauthors) : I like the Figure 20 there (but also a Figure 19 - of course ...) ... and the chapter begins with this fragment: “Extensive evidence exists from previous long control simulations showing simulated climate possesses large-scale variations on decadal to centennial timescales (Delworth et al., 1993; Delworth and Mann, 2000; Latif et al., 2004; Knight et al., 2005). Typically, these variations are associated with the principal modes of decadal variability of the climate system – the Atlantic Multidecadal Oscillation (AMO) (Enfield et al., 2001) and the Pacific Decadal Oscillation (PDO), sometimes referred to as the Interdecadal Pacific Oscillation (IPO) (Power et al., 1999). The AMO is a North Atlantic-centred mode in which sea surface temperatures (SSTs) vary coherently within the basin on multidecadal to centennial timescales, and which can have far reaching climate impacts (Knight et al., 2006). The PDO/IPO has a characteristic pattern of anomalously warm and cool SSTs in the Pacific Ocean that resembles a modified El Ni˜no pattern, and typically has a shorter timescale of about two decades (Kwon and Deser, 2007). So-called “perfect model” experiments (Collins and Sinha, 2003), in which sections of model control simulations are repeated after small initial perturbations, demonstrate the potential for multidecadal oceanic processes to provide a long-term memory of the initial state.” ... and ending with this sentence: “Future work may explore the response of extra ensemble members which start from deliberately chosen high or low AMO states.” Maybe in a much larger change in energy content in the ocean is responsible underestimated AMO? But then earlier (195? -1999) energetic "effect anthropogenic" would be considered too highly estimated ... I think it's time for these "Future work” ... -
Eric (skeptic) at 20:57 PM on 13 July 2011Seawater Equilibria
scaddenp, finally got that article. It is short and sweet. It confirms everything I have said above, namely "In response to an abrupt elimination of carbon dioxide emissions, global temperatures either remain approximately constant, or cool slightly as natural carbon sinks gradually draw anthropogenic carbon out of the atmosphere at a rate similar to the mixing of heat into the deep ocean" They then conclude that the elimination of CO2 will result in stable temperature. Then they issue a "hopeful" warning that " if we can successfully coordinate international emissions reductions in the coming decades, we can successfully restrict global temperature increases to a level that will prevent dangerous impacts on both human and environmental systems." For future reference, we can call this the "saved by the ocean" scenario. -
BBD at 20:48 PM on 13 July 2011A Detailed Look at Renewable Baseload Energy
Tom # 310 Excellent summary. Agreed! Thanks again. KR # 306 #307 Interesting analysis on power density at Waldpolenz. In order to prevent errors (!) I'd like to take time to consider what you say and it's bearing on Smil. One small point:Using 30% efficient CSP in a 2000 kWh/yr site (>230 Wh/m^2 average from MacKay, not the 200 BBD introduced),
I used 200W/m2 as this is the LAGI estimate. Not trying to muddy the waters... And thanks again to you. -
Eric (skeptic) at 20:11 PM on 13 July 2011Visions of the Arctic
The flip side of decreasing pack ice in Europe, Alaska, and of course Hudson Bay, is the increase in open water season in north certral Canada. One of my first posts on this forum /polar-bears-global-warming.htm#14708 was to point out that while the Hudson Bay populations were doing poorly due to decreasing ice, the other populations were only being impacted by hunting (at a rate of up to 10% per year) but were otherwise doing fine. The fate of an individual polar bear has little scientific relevance. The fate of a population is more concerning because of broader implications, but I don't have much knowledge of the history of historical variations in populations. But I doubt they were always where they are now. Warming in Arctic will favor the populations where the warm season is currently short. -
Eric (skeptic) at 19:43 PM on 13 July 2011Seawater Equilibria
Tom, thanks very much for the reference. I think you had pointed it out before, because it was in my saved papers folder. Reading through it again I see how some people may read it too quickly and conclude that one scenario represents "if we stopped producing CO2 today...." (my academic scenario I described above) But Archer is describing two potential, realistic scenarios, one where a moderate amount of 1000 GtC is released (compared to 2008's 337) and another with 5-6,000 GtC. Both have long tails and the 5-6,000 scenarios is especially long due to positive feedbacks. The first is essentially "we start to take action", the second, BAU. The simple model I use assumes that the CO2 reservoirs are passive. Substantial ocean warming (more than 1-2C) will negate that assumption as would permafrost melting or any other positive feedback. But as it stands, my model incorporates the current state (as of 2008) of all potentially active reservoirs or other positive feedbacks (as measured, not predicted) and the result is not substantially different from what one would expect looking at the diagram in Tom's link: http://earthguide.ucsd.edu/virtualmuseum/images/ReservoirsOfCarbon.html Given a slug of anthro-carbon into the atmospheric reservoir, the atmospheric concentration decays exponentially by migrating into the other reservoirs. Again, that depends on the rest of the system being passive (no substantial positive feedbacks). But exponential decay in that case is incontrovertible. Scaddenp, while I wrote the above I struggled with nature.com trying to purchase the article you linked. I'll comment here once I succeed and have a chance to read it. -
Doug Mackie at 19:12 PM on 13 July 2011OA not OK part 5: Reservoir dogs
Thanks Rob. Yes, at first glance it does look that way. But just because an equation can be written does not mean that all reactions are equal. There is a hierarchy and we discuss it in post 7. -
Rob Painting at 18:39 PM on 13 July 2011OA not OK part 5: Reservoir dogs
Well, I was going to say something about the equations implying more carbonates from ocean acidification, rather than less, but you mention this is covered in later posts. -
Paul D at 18:18 PM on 13 July 2011Visions of the Arctic
Mandas said "I am a wildlife scientist - similar to you I guess" I thought APirate was a school teacher?? -
Paul D at 18:08 PM on 13 July 2011Visions of the Arctic
Pirate said: "DB: Can you or anyone else, other than the photographer (if he is willing), legitimately say that polar bear in that picture is in legitimate duress?" Most wild life is under duress 24/7. And the word legitimate is a meaningless word outside human existence/knowledge. Last time I looked Polar Bears aren't human. Polar bears use sea ice to travel across the sea and hunt for food. They don't have much food sources on land, so the sea is a rich area for them to hunt. As sea ice melts more abruptly as a result of climate change, they are forced to swim more to reach ice flows or to return to land. This causes significant problems especially for a female polar bear with her young following her. Young polar bears can struggle moving from ice to water, especially if food is short. Ok so lets assume the ice goes and polar bears are forced to move in land. What is the impact? Well other species including humans have occupied that land for thousands of years. There is no real positive news for polar bears or for thousands of other species threatened by our behaviour. -
DLB at 17:27 PM on 13 July 2011OA not OK part 4: The f-word: pH
If water dissociated more, would the pH decrease? Intuitively I would have thought it would still be classified as neutral. -
Doug Mackie at 17:15 PM on 13 July 2011OA not OK part 5: Reservoir dogs
@DLB Do you mean "how do we know what pre-industrial ocean pH was?" or do you mean "how is ocean pH measured?" -
Doug Mackie at 17:10 PM on 13 July 2011OA not OK part 5: Reservoir dogs
I'm really looking forward to a substantive comment about the science. -
Tom Curtis at 17:03 PM on 13 July 2011A Detailed Look at Renewable Baseload Energy
KR @307, you would probably be interested in these comparisons, also at LAGI. Solar vs Tar Sands:
Solar vs Shale Gas:
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DLB at 17:00 PM on 13 July 2011OA not OK part 5: Reservoir dogs
You say since the beginning of the industrial revolution, H3O+ has increased by 29% in sea water. Has this been measured by some sort of proxy, or is it based on calculations from atmosphere to ocean?
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