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logicman at 06:02 AM on 8 March 2011Icing the Medieval Warm Period
Re: comment #78 - moderator response. Many thanks for the warm welcome! Yes, I did mean the Spielhagen et al paper. I mistakenly copied from my recent urls list the one above Spielhagen. The link I mistakenly posted is a paper suggesting the possibility of sea ice recovery in 2 years after an ice free summer. I have been 'lurking' here for far too long and thought it was about time I signed on/in/up. Best regards, Patrick Lockerby http://www.science20.com/chatter_boxModerator Response: [DB] Patrick, I think your html for the no follow code string in your SkS Sign-on ID is hashed (plus I'm not sure that the no follow string will work there anyway, but it's worth a try; for some reason it shows up as logicman w/ no link in the Recent Comments window, but it's hashed up on the actual threads). Between the left-arrow symbol and the right-arrow symbol should be this string: a rel="nofollow" href="http://www.science20.com/chatter_box" -
Rob Painting at 05:56 AM on 8 March 2011A Real-World Example of Carbon Pricing Benefits Outweighing Costs
Muoncounter @ 83 - According to World coal: "there is enough coal to last us around 119 years at current rates of production." Not going to be exhausted any time soon. Probably not, but if oil runs out, how is all that coal going to be extracted from the ground and transported?. -
Rob Painting at 05:53 AM on 8 March 2011A Real-World Example of Carbon Pricing Benefits Outweighing Costs
Dana 1981 @ 82 - No it's not. Transportation can be accomplished with electric vehicles to a large degree Personal transport?. Yes. Heavy machinery?. No. We still have a long way to go, and better get cracking in creating something to replace it. -
hank at 05:22 AM on 8 March 2011Climate sensitivity is low
http://www.barrettbellamyclimate.com/page17.htmModerator Response: Please provide some context for links. Link-only comments will be deleted. -
muoncounter at 05:18 AM on 8 March 2011A Real-World Example of Carbon Pricing Benefits Outweighing Costs
Gilles #66: "Even if they halved their energy consumption ... I'm just saying this will not reduce the overall consumption. And it won't either reduce the total amount of fossil fuels that we can extract" I don't follow that reasoning at all. Gilles#72 "I am arguing that we MUST do anything we can to spare FF, first because they are being exhausted ... " According to World coal: "there is enough coal to last us around 119 years at current rates of production." Not going to be exhausted any time soon. Add in (from USEIA): "The combustion of coal, however, adds a significant amount of carbon dioxide to the atmosphere per unit of heat energy, more than does the combustion of other fossil fuels" and your argument reduces to one of failure to act. -
Bob Lacatena at 04:57 AM on 8 March 2011Interactive animation of the climate change impact on agriculture
I think one major failing in the model, one which can make climate change seem good by increasing crop yields, is the question of appropriate precipitation ("appropriate" as in how much, how often, and at what time of year from the crop's perspective). That is probably part of the difference in the low/mid/high latitude setting, but since precipitation changes aren't entirely governed by latitude, I'd rather see something just a little more elaborate... either a "precipitation gauge" which responds in concert to altering temperature (i.e. not a control itself -- you change temperature, and that changes precipitation) with a range of changed values, and therefore a range of expected crop yield due to the precipitation range, or else perhaps more simply 3 or 4 separate "crop yield" boxes (zones), to represent various general climate zones ("wet", "arid", etc.), perhaps each with a percentage to show how much of the world will fall into that category in various scenarios. I guess my main point is that I think that changes in precipitation are a far more important and damaging factor in the long run, and it's the intersection of the two (temperature and precipitation changes) that are going to really hurt crop yields... you have to get better temperatures and better precipitation to increase crop yields, while only one of those two needs to drop to greatly reduce crop yields. And in fact, in some circumstances what would otherwise be a productive increase in temperature but combined with a reduction in precipitation, even if only for a several week span during an important part of the growing season, could exacerbate the precipitation problem and make things worse. That is, the effects of changes in temperature and moisture aren't simply additive, but interact in a complex way. -
hank at 04:32 AM on 8 March 2011Climate sensitivity is low
http://www.gfdl.noaa.gov/blog/isaac-held/2011/03/05/2-linearity-of-the-forced-response/ hat tip to: http://scienceblogs.com/stoat/2011/03/dr_roy_spencer_is_sad_and_lone.php -
hank at 04:29 AM on 8 March 2011Climate sensitivity is low
> what's next, redefining the laws of physics ....? Chuckle. Yep. http://www.google.com/search?q=%2Bspencer+%2Bpoptech+%2Brefute -
RickG at 04:21 AM on 8 March 2011Interactive animation of the climate change impact on agriculture
Camburn, I would think the model is based on normal agricultural conditions with temperature being the primary variable. In that respect it would be useful. However, I think the danger with a warming and changing climate is that agricultural zones will also change; therefore, migrate. With growing global population and urbanization, there is are few places left where they can migrate were agriculture is possible. -
dana1981 at 04:14 AM on 8 March 2011A Real-World Example of Carbon Pricing Benefits Outweighing Costs
Gilles #72 -"Oil is needed for transportation, heating"
No it's not. Transportation can be accomplished with electric vehicles to a large degree, and there are alternatives to heating with oil."mainly because climate is hotter, maybe ?"
No, because California has implemented energy efficiency technologies. Our per capita energy consumption has barely increased over the past 30 years. The rest of the country's has increased significantly."without carbon, there is nothing but the poorest life you can imagine."
First of all, nobody is saying we're going to eliminate all carbon, and secondly, claiming that we can't have a high tech lifestyle without massive carbon emissions is utterly absurd. -
Camburn at 04:05 AM on 8 March 2011Interactive animation of the climate change impact on agriculture
Rick: Grains crops benifit from higher levels of co2 during the growing season. As you can see from your chart the level of co2 is now higher than in the recent past. If you were to look at world vegitation maps/health you would see that there is a trend to increased health worldwide of plants. This is in reponse to higher levels of co2. I don't have the studies at hand, but there have been field studies done in the US as to what happens to corn growth and grass growth with higher levels of co2, everything else remaining constant. The response is quit good. My main point is to the usefullnes of the application presented. There are so many variables that affect plant health that using temperature as the metric does not produce a meaningful result. If everything else is constant, then one could surmise that the results of the graph show that more heat is good for ag output. -
scaddenp at 03:51 AM on 8 March 2011The Climate Show Episode 8: Kevin Trenberth
stevee - what has your comment got to do with the topic? This is a site to discuss the science of global warming - plenty of other places for raves about it. Since you are obviously skeptical, why dont you pick the argument against (one per post), that you find most convincing, look at up in the "Arguments" list, and then tell us why you think the debunk is wrong. -
RickG at 03:22 AM on 8 March 2011The Climate Show Episode 8: Kevin Trenberth
Stevee: Has it been determined, scientifically, if the ClimateGate (Hide the Decline) emails were hacked, or leaked ? I doubt they were leaked but it has been scientifically determined that they were deliberately misrepresented. -
stevee3906 at 03:11 AM on 8 March 2011The Climate Show Episode 8: Kevin Trenberth
Has it been determined, scientifically, if the ClimateGate (Hide the Decline) emails were hacked, or leaked ?Moderator Response: [muoncounter] There are a variety of existing ClimateGate threads. Try the Search function. -
RickG at 03:11 AM on 8 March 2011Interactive animation of the climate change impact on agriculture
Camburn: I was not surprised to see a rise in production from more warmth. That is pretty much a given. The added co2 also contributes to a rise in production. One thing to consider is that a number of fruit trees require a minimum number of days below a certain temperature during winter or they will not produce in the spring/summer. As for annual crops, are you familiar with the Keeling curve? See graph below: peaks in the curve are winter while valleys are summer.
Crops and other vegetation take up CO2 during the summer but release it during the winter through decay. Any extra CO2 intake by plants will be released after the growing season.
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stevee3906 at 03:09 AM on 8 March 2011Interactive animation of the climate change impact on agriculture
It is a very simple model. Yet it provides answers to a tenth of a percent. Soil types, soil status, diseases, fertilizers, timing of moisture and weather, seed types, temperate zones all play a role. As I side note, I plant 1,000 trees every spring. In Northern Minnesota the limiting factors are summers to short and too cool, and winters too long and too cold. -
michael sweet at 02:53 AM on 8 March 2011Interactive animation of the climate change impact on agriculture
We need to keep in mind that this is a simple model. As Camburn pointed out, CO2 fertilization might further increase production while lack of rain, or floods, would lower prduction. On the other hand, this model gives a starting point so we know what we need to deal with. Perhaps more irrigation would be enough to adapt if water is the main limiting factor. If no irrigation water is available we might need to move. If heat alone is the limiting factor we need new cultivars that are heat resistant or we must switch to other crops. This model is not the final word, it is a learning exercise. -
Philippe Chantreau at 01:50 AM on 8 March 2011Interactive animation of the climate change impact on agriculture
"The added co2 also contributes to a rise in production." There is little to no evidence showing this to be true in the fields. Commercial greenhouses using enhanced CO2 to increase yields have to use 800 to 1200 ppm concentrations to see any results, with all other factors being optimized. -
KR at 01:46 AM on 8 March 2011Icing the Medieval Warm Period
Gilles, everyone - might I suggest taking the models conversation to the Models are unreliable thread, where this topic is relevant? I don't believe it's a core part of a MWP discussion.Moderator Response: [Dikran Marsupial] Agreed, further discussion of models should be conducted on that thread. -
KR at 01:41 AM on 8 March 2011Blaming the Pacific Decadal Oscillation
johnd - I'm not certain I can follow your logic there. Water vapor rising into the atmosphere reaches a point where the air is cool enough to condense it; cooler than the water vapor. When it cools and condenses the energy involved in that transition is given over to the air, which warms. That heat energy is not inconsiderable - the updrafts in thunderstorms and hurricanes are driven by the heat from condensing vapor. The downdrafts are considerably cooler. Thunderstorms end when there is insufficient moist air drawn in, hurricanes weaken when they get over land and lose the warm moist air over the oceans as an energy source. -
Camburn at 01:41 AM on 8 March 2011Interactive animation of the climate change impact on agriculture
Yes, I have something to add Daniel. The timeing of any heat units is critical to how plants respond. Without knowning the underlying metrics that this model is based on, the model us quit useless. The IPCC model is not temperature specific. I will use one crop as an example: Wheat. Wheat likes cool weather when it is tillering. Once tillering has completed, it likes warm weather. Flowering wheat, which is the reproductive period, likes dry weather as any moisture contributes to leaf disease and fusarium. Once wheat has finished flowering, a shot of rain is good and warmer temps once again are desired. It is about timing of heat units. I was not surprised to see a rise in production from more warmth. That is pretty much a given. The added co2 also contributes to a rise in production. Without more information on how this program was constructed it is impossible to see if the results are credible. As a side note, I am a farmer. Hence, I recognize what is required.Moderator Response: For some scientific studies of the effects of CO2 and heat, see the summary by the U.S. Dept. of Agriculture, and other studies, linked in the comments of the thread "CO2 is not a pollutant." -
Bern at 01:27 AM on 8 March 2011The Climate Show Episode 8: Kevin Trenberth
The problem with 'super microbes' is that they're very hard to turn off when you've reached your target CO2 concentration, whereas industrial plants you just flick the switch... Well, I stayed up well past my bedtime to watch/listen to the show, and it was well worth it, thanks. I did note with interest, however, the discussion of the new process for capturing atmospheric CO2 using a solid amine structure, with low temperature release. This sounds ideal for a solar-powered carbon capture factory (in fact the New Scientist article quotes a figure of perhaps a million tons per day from a commercial plant - that's almost enough to capture the entire CO2 emissions from Australia, from just one plant!) The other part of the equation would then be doing something with that CO2. There are solar thermal methods to combine it with H2O to form CO + H2 + O2, to give a hydrogen feed, and the CO can be further fed into other processes to produce hydrocarbon fuels. But if the aim is to sequester the carbon, you'll still need to find something to do with the CO or subsequent hydrocarbons. It would be somewhat ironic if we ended up synthesising heavy oils, only to pump them deep underground into deplete oil reservoirs... Expensive? Sure. But what adaptation measure isn't? -
Arkadiusz Semczyszak at 01:14 AM on 8 March 2011A Real-World Example of Carbon Pricing Benefits Outweighing Costs
I, as a resident of a country whose huge areas were destroyed by the coal mines - I - the "great enemy” of fuel industry based on coal and petroleum - would that it disappeared as quickly as possible. However, energy-saving technologies and renewable energy sources requires time and large financial outlays. Even - a relatively modest effects - was founded in Kyoto - but require very fast action. Beyond a certain amount of CO2 in the atmosphere, the need for several thousand. years to the biosphere can remove the surplus. Loss of Carbon from the Deep Sea Since the Last Glacial Maximum, Yu et al., 2010..: “Combined benthic δ13C and [CO3 2-] results indicate that deep-sea-released CO2 during the early deglacial period (17.5 to 14.5 thousand years ago) was preferentially stored in the atmosphere, whereas during the late deglacial period (14 to 10 thousand years ago), besides contributing to the contemporary atmospheric CO2 rise, a substantial portion of CO2 released from oceans was absorbed by the terrestrial biosphere.” Rapid reductions in CO2 are achievable only through widespread application of CCS - global CO2 emissions growing rapidly - especially in China. CCS will surely raise the cost for energy - this is not possible that improved energy efficiency. This is after all only a mere storage of CO2. CCS "will take" a large part of investment in renewable energy sources. Even more (and more) will make us from the fuel concerns - energy supplies based on fossil fuels. Corporations such as Statoil and Shell - has for many years - in Europe - the fund's most "alarming" researches on current and future GW. CCS will give preference position - particularly in the U.S. - the big oil corporations (this is the expensive technology - that she was a fully secure.) Their leaders already argue that the large-scale introduction of CCS - that gives you the quasi-monopoly position - will be able to run a cost-effective production of energy from methane clathrates (including liquid fuels production - their price at CCS will have to be higher.) Methane clathrates will be "sufficient" for USA on 3,000 years ... At the CCS we can (for a long time), forget about "peak oil" and "clean energy" ... -
SoundOff at 00:38 AM on 8 March 2011The Climate Show Episode 8: Kevin Trenberth
Bern: “I'm talking about plants to capture CO2 from the atmosphere to reduce concentrations to a "safe" level.” Bern, of course, is talking about industrial plants. Living biological plants do this all the time; it’s where the fossil fuels came from originally. Might we someday genetically engineer some super microbe to accomplish the desired task? Hopefully it won’t entail covering our oceans in a green slime. -
ranyl at 22:52 PM on 7 March 2011A Real-World Example of Carbon Pricing Benefits Outweighing Costs
Gilles, "health and welfare are POSITIVELY correlated with the use of fossil fuels, and that without carbon, there is nothing but the poorest life you can imagine." Well apart from general well being index and mental health of course. -
Byron Smith at 22:36 PM on 7 March 2011Interactive animation of the climate change impact on agriculture
Of course, it is also critical to notice that the temperature change in the thermometer is *local*, which means that my earlier reading was not actually so misleading after all! A *global* temperature rise of 1ºC is probably sufficient in most areas to push *local* land-based temperature rises above the point of where crop effects are positive or neutrality and into deficit, since (a) local temperatures over land increase faster than over oceans and (b) local temp rises generally increase relative to the global average for higher latitudes (especially in the Northern Hemisphere). So in terms of the big picture, going much beyond a 1ºC global rise would likely mean net crop losses, even with adaptation. -
Byron Smith at 22:30 PM on 7 March 2011Interactive animation of the climate change impact on agriculture
(When I speak of crops going well, I meant in comparison to my impression from having read a bit on this topic previously. Obviously, after a certain point things are grim no matter how well we adapt. It was just that that point was a little higher than I had previously thought.) -
Byron Smith at 22:29 PM on 7 March 2011Interactive animation of the climate change impact on agriculture
What surprised me was how well crops did, especially at higher latitudes. I was under the impression that almost any temperature rise was bad for agricultural output in the tropics and almost anything much above 1ºC was bad in temperate regions. It would be useful to know the percentage of global production found in each of the two regions, in order to be able to calculate the global effect of different temperature changes. Also, is this only for the Northern Hemisphere? Or is the graphic simply misleading? -
Marcus at 22:10 PM on 7 March 2011A Real-World Example of Carbon Pricing Benefits Outweighing Costs
"If I am getting latent heat from the environment that allows me to turn my furnace off, I am now emitting less CO2". Wow, so its OK to mess with the atmosphere just so you can claim you're consuming less fuel in winter? Here's an idea-try insulating your home or-heaven forbid-where a jumper indoors, that'll cut your fuel bills more than milder winters. You are also aware that you can heat your home with an A/C or with relatively clean landfill gas? Also, try living here in Australia where every Summer we're getting increasing number of nights that are *above* 20 degrees C-thus forcing us to consume more electricity to keep our homes cool at night. As I said above, RSVP, you've long since reached the point where you actually *detract* from the debate, rather than contribute anything meaningful. Personally, I think you should refrain from posting until such time as you're prepared to say something....I don't know....moderately *intelligent*? -
Ian Love at 21:43 PM on 7 March 2011Blaming the Pacific Decadal Oscillation
johnd at 16:37 PM on 7 March, 2011. You appear to be giving yourself contradictions by thinking of water droplets as not part of the air - surely what is crucial is that they are there in the atmosphere, and probably at equilibrated temperature with the air. The water vapour forming droplets releases heat into the atmosphere, which necessarily increases the atmosphere's temperature. That heat has been carried from the surface liquid water into the atmosphere by the evaporation-condensation cycle. So the bottom line is that it warms the atmosphere. -
adelady at 21:43 PM on 7 March 2011A Real-World Example of Carbon Pricing Benefits Outweighing Costs
rsvp, but that's where you live. Try it in a city which regularly has several days in succession over 35C. All you need to do is look at how a "heat wave" is defined in different locations. Here it's 5+ days over 35C or 3+ days above 40C. Other places have other definitions. I can assure you that a summer with no heat waves can still rack up an impressive total of weeks requiring a lot of air conditioning unless the household has done some serious work on passive cooling. And it is much, much easier to warm people (at least enough to maintain life) during cold weather than it is to protect from life-threatening heat. -
RSVP at 21:08 PM on 7 March 2011A Real-World Example of Carbon Pricing Benefits Outweighing Costs
RickG #74 "You have data showing global fuel consumption is decreasing? Or am I asking an inconvenient question? " Global fuel consumption may be increasing, but it is not due to warming. The inconvenient answer is that my personal winter bill has increased while consumption has actually gone down. Marcus #75 If I am getting latent heat from the environment that allows me to turn my furnace off, I am now emitting less CO2. My air conditioner on the otherhand happens to run off of electricity (maybe yours is different). I also only have to turn on this airconditioner about three days in the summer at most, whereas heating is big deal and must be going for at least four months. -
Paul D at 20:53 PM on 7 March 2011Interactive animation of the climate change impact on agriculture
I should have said in 4 that the temperature can be set to zero temperature change, rather then zero temperature. -
Marcus at 20:23 PM on 7 March 2011A Real-World Example of Carbon Pricing Benefits Outweighing Costs
"OK Marcus, so how is the electric car of your friends working ? " Man, this is such a pointless question Gilles-it seems to imply that the "wrong" answer will invalidate my basic premise-which is that our current transport network represents a massively inefficient use of a rapidly declining resource. Or are you trying to suggest that people sitting in bumper-to-bumper traffic, consuming 1/5th of the petrol in their cars to go *nowhere* is a good thing? As it happens, most of my friends either use buses/trains like me-or get around by bike. Those friends of mine who do have electric cars are very happy with their purchase, as they've seen a significant reduction in their maintenance & "fuel" costs. -
Marcus at 20:17 PM on 7 March 2011A Real-World Example of Carbon Pricing Benefits Outweighing Costs
Come on Rick, we all know that RSVP has nothing of value to add to this debate. He seems to forget that the flip-side is too much heat in Spring & Summer, & reduced rainfall too-which will of course hurt agriculture. Hotter Summers will also result in greater fuel consumption as people try & keep cool. Given that its harder to get cool than warm up, this will have definitely lead to a net *increase* in fuel consumption over the course of any given year. So not only is RSVP's question totally pointless, it's also based on a total *falsehood*. -
RickG at 19:59 PM on 7 March 2011A Real-World Example of Carbon Pricing Benefits Outweighing Costs
@ 73 RSVP Really! You have data showing global fuel consumption is decreasing? Or am I asking an inconvenient question? -
Dan Olner at 19:58 PM on 7 March 2011Interactive animation of the climate change impact on agriculture
DIkran: "Nobody thinks that model output is data. Models exist to demonstrate the consequences of a set of assumptions." I'm stealing that sentence for my thesis! Seriously, no-one *should* mistake model output for data but you'd be amazed (or maybe you wouldn't) how muddled people's thinking is on this.Moderator Response: [Dikran Marsupial] Glad to hear I have done something useful this morning! ;o) -
Paul D at 19:53 PM on 7 March 2011Interactive animation of the climate change impact on agriculture
Maybe my eye sight is worse than I thought. But the variable is temperature, in fact the text says: Mean Local Temperature Change. Which suggests to me that the interactive educational tool is designed to show what would happen with a temperature change. Indeed, I can reduce the temperature to zero. Possibly the only fault is that it doesn't go into negative temperatures. Given that the vast majority of scientists understand the physics of temperature change and the effects. I would think the results are obvious. After all is it not skeptics that attach great meaning to the ability of growing grapes in different climates? Or are comments 1, 2 and 3 suggesting skeptics are using a poor metric for judging climate? -
Gilles at 19:44 PM on 7 March 2011Icing the Medieval Warm Period
"No subtraction is being done. " By "subtraction", I mean switching off the anthropic forcings in the runs. Is it what is done, or no? If yes, I repeat : the fact that you worsen a fit by switching off a component AFTER you have adjusted your fit to data is not surprising : it is always true. And it is hence not very useful to "prove" anything on the validity of your model. "GCMs are not statistical model fits, they are models of the physics, that allow you to find out the consequences of a set of assumptions regarding climate physics." DM : we saw in the post about sensitivities that there was still a fairly large range of different sensitivities compatible with the data (or they would be dismissed by them). Do the "different curves" used to generate this interval include all these values of sensitivities, yes, or no ? and if yes, how can they all be "equally true" ? If you can explain the same data with different physical models, you're pretty sure that they are almost all (but one) wrong. And you cannot exclude they are all wrong. This is not a situation usually associated with a "well understood" theory.Moderator Response: [Dikran Marsupial] You are assuming that the model with only non-anthropogenic forcings was not independently "tuned" (as far as tuning is possible). I doubt that is the case. As I said, the GISS Model E code is freely available, so you can always go and check for yourself. Secondly, the diagram shown was not meant to "prove" anything on the validity of the model. If there is a large range of sensitivities that are compatible with the data, that suggests that the models would be relatively insensitive to their adjustment. Lastly, no, all models are wrong (GEP Box); nobody expects any of them to be exactly right. The question is, are they sufficiently right to be useful. YOu have yet to provide any evidence that they are not useful, we all know they are "wrong", that is entirely uncontraverisal. -
RSVP at 19:38 PM on 7 March 2011A Real-World Example of Carbon Pricing Benefits Outweighing Costs
If winters are tending to be milder, it means the planet's energy efficiency has increased and thereby lowering average fuel consumption. Why is this fact always overlooked...or is this a sorely "inconvenient truth"? -
Dikran Marsupial at 19:38 PM on 7 March 2011Interactive animation of the climate change impact on agriculture
As we have no data for future climate (as it hasn't happened yet), please explain how we can forecast the effects of climate change on agriculture without a model? Nobody thinks that model output is data. Models exist to demonstrate the consequences of a set of assumptions regarding climate physics; they also allow our understanding of climate physics to be falsified, by making testable predictions. Disregarding any argument just because it involves the use of models is deeply unscientific. -
logicman at 19:35 PM on 7 March 2011Icing the Medieval Warm Period
Daniel: with reference to your moderator replies to comments #15 and #24 - here is the url for the original temperature anomaly graphics: earthobservatory.nasa.gov Of relevance to modern temps vs MWP is the recent paper Recovery mechanisms of Arctic summer sea ice. S. Tietsche,1 D. Notz,1 J. H. Jungclaus,1 and J. Marotzke1 The paper states clearly that temperatures in the Fram Strait are higher than at any time in the last 2ky - including the MWP. Tietsche_GRL_2011.pdfModerator Response: Hey, Welcome to Skeptical Science! Thanks for the link to the graphic (I haven't yet had the time to search for it, so many thanks)! Far be it for me to correct you, but I think you may have meant Spielhagen et al, 2011 wherein they present a 2,000 year marine sediment proxy record showing the unprecedented warming of which you speak. BTW, if you want to link to your website, please do so as many of the regulars here would find it invaluable. Thanks again! -
Camburn at 19:30 PM on 7 March 2011Interactive animation of the climate change impact on agriculture
The supposed underlying data ref IPCC is based on models which is based on more models. That is what I meant by underlying data. Models are not data but only assumptions. -
Camburn at 19:28 PM on 7 March 2011Interactive animation of the climate change impact on agriculture
Without knowing the underlying data used to make this little program, the results are pretty much worthless.Moderator Response: [Daniel Bailey] Do you have something constructive to offer besides the obligatory drive-by handwaving? As it stands, your comment contributes nothing to the dialogue on this thread. -
ms2et at 19:26 PM on 7 March 2011Blaming the Pacific Decadal Oscillation
This is a most interesting topic and one which I think addresses a critical point about the climate system's response to certain forcings. It's very refreshing to see such an informative discussion which is purely objective and devoid of any personal attacks or sarcastic remarks, unlike some other sites. I'm a skeptic of AGW but always enjoy reading here because the debate is civil and friendly. This site's comments section is arguably the best for a balanced and thorough examination of the science. -
Bern at 17:42 PM on 7 March 2011The Climate Show Episode 8: Kevin Trenberth
I forgot to add - I'm not talking about plants to capture CO2 from fossil fuel burning - I'm talking about plants to capture CO2 from the atmosphere to reduce concentrations to a "safe" level. Perhaps enormous factory ships, sitting in the relatively calm & sunny equatorial waters? Capture the CO2, crack it in solar furnaces, compress to briquettes of carbon, and dump overboard to the deep ocean... How long would it stay there, though? Would, say, briquettes of graphite be gobbled up by some bottom-dwelling bacterium, and turned back into methane or CO2? And if it was, how long would it take that gas to make it back to the surface from the abyssal waters? -
Gilles at 17:38 PM on 7 March 2011A Real-World Example of Carbon Pricing Benefits Outweighing Costs
OK Marcus, so how is the electric car of your friends working ? Dana : "we must find a new energy source to replace carbon fuels. Period. So, why aren't we looking?" We are looking. There's solar (PV and concentrated thermal), wind (offshore and onshore), geothermal, tidal, etc. etc. gasp. Oil is no more used for electricity, at least in the countries that can afford these expensive means of productions. Oil is needed for transportation, heating, carbochemistry, and all this won't help much. "Californians use less per capita energy than most of the rest of the USA, " mainly because climate is hotter, maybe ? "The scientific evidence is what it is, and it clearly shows that carbon is a threat to humanity." The first scientific evidence is that ALL indicators or wealth and welfare are POSITIVELY correlated with the use of fossil fuels, and that without carbon, there is nothing but the poorest life you can imagine. Mucounter : "You seem to be arguing against doing anything because in your opinion, nothing will be an equitable fix. " You misunderstood me : I am arguing that we MUST do anything we can to spare FF, first because they are being exhausted (and even if CO2 had no IR absorption line), but that this will not reduce the overall amount we will extract in the future. -
Bern at 17:33 PM on 7 March 2011The Climate Show Episode 8: Kevin Trenberth
Chemware - yes, I'm well aware of the energy costs - I would expect the capturing & cracking to be powered by nuclear or solar means (I seem to recall watching a video of a concentrator dish that was used in experiments to crack CO2). I completely agree that the carbon capture & storage (CCS) is a fool's errand that will consume enormous resources (both in money and engineering resources) that would be better spent on developing alternative energy supplies. After all, a reduction of, say, 10% emissions now (due to CCS) might cost as much as developing alternate energy sources that can cut emissions by 90% in the near future. It seems that, given limited funds, we should take the longer-term view - especially as, after spending the money on CCS, we'd then need to spend it *again* on the alternate sources anyway... -
Gilles at 17:23 PM on 7 March 2011Icing the Medieval Warm Period
"The second graphic Tom Curtis shows here is the result of multiple model runs using various forcings. " Another strange thing : it is unusual to cover an experimental curve with a set of DIFFERENT models. Through the use of multiple wrong models, I can always cover everything in their interval. What does it prove ?Moderator Response: [Dikran Marsupial] It isn't at all unusual (in fact it ought to be standard operating procedure). The purpose is to show the uncertainty in the projection/hindcast based on our current understanding of climate physics. Climatologists are generally very happy to talk about model uncertainty; if they only showed the best model fit, they would be accused of cherry picking. BTW GEP Box said "all models are wrong, but some are useful"; you have asserted they are wrong, but have provided no evidence that they are not useful. -
Gilles at 17:21 PM on 7 March 2011Icing the Medieval Warm Period
Mucounter : Tom and myself were obviously talking about the first graph (the NZ trend), because he introduced the sentence just before showing it. Concerning the "conspicuous rise " in the high southern latitudes between 1930 and 1940, I don't see how to blame anthropic forcings for it : did anthropic forcings really rise more in this period ? KR : as you probably know, all these models have free parameters, especially for clouds, and the outputs are selected by some kind of "best fits". So it's not the same to do a "best fit" without anthropic forcings, and to do a best fit with anthropic forcings and THEN substract them. Now you may also know that if I had added new free parameters, I would always improve the fit. I could improve the fit with natural forcings only by adding the position of Jupiter, Saturn, and Pluto, and then argue that if I substract these influences, the fit is worse. That is mathematically perfectly correct - and yet physically absurd. This is not a correct way of reasoning.Moderator Response: [Dikran Marsupial] No subtraction is being done. The breadth of the error bars tends to be due to the variability in model runs, not the variability in parameters. GCMs are not statistical model fits, they are models of the physics, that allow you to find out the consequences of a set of assumptions regarding climate physics. The degree to which they can be tuned is fairly limited. If you (or anyone else) think the observed 20th century climate can be modelled without anthropogenic climate by adding a few parameters, go for it, the source code of the GISS model E is publically available as a starting point. If you had to include the positions of Jupiter etc. to do so, that would just indicate that anthropogenic forcings are important; there is good evidence that carbon dioxide is a greenhouse gas and affects climate; that is not the case for the position of Jupiter!
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