Arguments
Recent Comments
Prev 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 Next
Comments 23201 to 23250:
-
Tom Curtis at 23:47 PM on 17 August 2016Climate urgency: we've locked in more global warming than people realize
Zoli @17, here is a schematic of the long term carbon cycle:
As you can see, CO2 enters the atmosphere through volcanic activity, and is drawn down out of the surface system by rock weathering bringing the carbon into the ocean as Calcium Carbonate (CaCO3) which then falls out as sediment and is taken into the Earth at subduction zones. Over the long term, there is an approximate balance between the rates of these two processes. If volcanism increases, or the rate of rock weathering decreases, however, that balance will be disturbed and CO2 will build up in the atmosphere until a new equilibrium is reached. If volcanism decreases or the rate of rock weathering increases, the reverse will happen and the new equilibrium will be established with a lower CO2 content.
Several things effect the rate of rock weathering including the amount and elevation of exposed rock, the rate of rainfall, and temperature (with warm temperatures accelerating rock weathering). The first is primarilly effected by the rate of mountain building (orogeny). Thus, when the Indian sub-continent collided with the Asian continent, pushing up the Himalayas, that also increased the rate of weathering, thereby drawing down CO2.
-
Aaron S at 23:46 PM on 17 August 2016CERN CLOUD experiment proved cosmic rays are causing global warming
I sincerely do appreciate such a thought out and well written response by Tom Curtis and others. So I want to reply with my concerns.
1) You are correct- the correlation is poor since about 2000. However, if you factor in this was a massive solar max based in isotopes and SSN and if you consider lags in the system associated with oceanic circulation (like AGW theory does for the delay in Antartic warming or PDO and the Hiatus) then you could increase stored heat and continue to even warm beyond the decrease in forcing when stored heat is realeased later. I have zero issue with the PDO storing heat for an entire negative positive couplet and there are much longer circulation cells. Let us remember to- I do believe in AGW and CO2 as a GHG- I just think ignorming solar activity and cosmic rays is not valid based on existing data. Also there is the obvious- the correlation between slope of warming trend in Hadcrut and A2 model warming has poor correlation over the same duration (The Hiatus is Real- Roberts et al. Nature CC 5, 2015). So correlation in this case is not a good argument either way as we are both aware climate is a complex system with feedbacks and lags.
2) Maunder minimum to modern maximum is a totally different situation than a Schwabe 11 yr minimum during a max or a decent from a max and we have not observed the impact from direct obserbations; the isotope record (Steinhilber et al) shows the intensity of the dipole is about the same (a little less for the dipole) as the intensity during the change from the Maunder to the modern max. Furthermore, the Maunder-scale cycles have much higher periodicity than the dipole- which means the wave has more energy given about the same amplitude. Period is important and if I speculate and dream a bit perhaps there is a dynamic equilibrium reached with longer duration changes related to the dipole that minimizes the impact. So I don't get your argument or suggestion that it is 17x the strength because isotopes (only data we have) say otherwise and the higher frequency change also supports more energy for the Sun. So considering that you don't have direct measurments to address anything but the interval during a solar max it seems a rather biased evaluation to me, but perhaps I am missing something as this is a stretch for my understanding. Thanks for making me think about this- it was a pleasant challenge and good learning.
3) Short term solar storms may not be long enough duration to trigger a response. The causal relationship between CR and intra annual solar activity is weak, but they are related to intra-annual events not short pulses.
4) The Earth's magnetic field is dynamic and dominates the Tropics- Agreed. Thanks for sharing that data. I think you need to add "during a solar max" because we don't know what the Maunder looked like- but it did likely impact Northern latitudes. Perhaps this explains the regional nature of the Little Ice Age.
5) You do not address the very strong correlation between the monsoon and cosmic ray intensisty. Correlation requires caution, but each vary greatly in time with a significant decadal scale lag of climate behind magnetics. THis pattern supports causation rather strongly. Nor do you address the quantified causal relationship at the intra-annual period in the other paper. Also, there is data from other proxy that climate responds to the sun's magnetic field. Each support the point in a independent way.
I am fortunate- I am arguing that there is now sufficient evidence to include a stronger sun scenario into the climate models. It is much more difficult to defend than your position to not consider the data validn. Your data is to short (during the max) or to long (100k yr doesn't have century scale resolution) for me to say it meets this threshold. Cosmic rays need included in the models.
Thanks for the opportunity to learn- you are a good teacher.
-
Zoli at 17:45 PM on 17 August 2016Climate urgency: we've locked in more global warming than people realize
The video says half of the CO2 increase would disappear within 20 years without further emissions. How was possible in the past to have high CO2 levels on the long term like in the Pliocene and earlier?
-
RedBaron at 15:41 PM on 17 August 2016Climate urgency: we've locked in more global warming than people realize
Willi,
You are right, and yet drew a different conclusion. Rainforest destruction is primarily for lumber. Crops come next until the soil deteriorates so badly no crops will grow. In those soils that doesn't take long. Once unfit for crops, then comes grazing, because that can restore soils.
While it is true that rainforest destruction is at least partly due to animal ag, in this case the real destruction aside from the timbering to start the process comes when it is cropped with corn and soy for supplying CAFOs. Grazing actually can be the first stage in ecosystem restoration if done properly. Once soil health is improved enough, then either let the ecosystem revert to jungle then forest. Or even plant.
The other point you may not know, is that on prime agricultural land, one can actually produce as much or more meat per acre at far less cost than growing commodity crops to feed animals.
The CAFO system does not actually increase meat produced per acre, comparing like to like. Not only can you produce animal foods where the conditions are unfit for crops, a similar advantage in food per acre happens on that prime land too. Whereas the meat industry has managed to propagandize people thinking that we don't like CAFOs but it is the only way to meet supply for a growing population, the truth is it actually is the opposite.
So yes, we certainly need to stop slash and bun of the forests, But if what you say is true, and we need to actually produce more on less acres without clearing forest, the solution is instead of clearing forest, to convert the prime acreage that supplies CAFOs to prairie again. The prime soils are NOT clear cut forests. The prime soils are plowed prairies.
-
wili at 15:10 PM on 17 August 2016Climate urgency: we've locked in more global warming than people realize
RedBaron, good points, but looking at this in absolute terms is not useful. The whole planet does not have to (and is not going to) turn vegan. So there will always be grazing use for those lands that are not well suited for other ag.
The problem is that, right now, more and more people are eating higher and higher levels of meat, and that is simply unsustainable, and is also contributing to global warming.
The are many pieces to the puzzle, and one of them is certainly reducing (and avoiding increasing) the amount of meat and dairy consumed, since most of this is now produced in ways that greatly increases GHGs in various ways, including rainforest destruction (especially in the Amazon).
-
One Planet Only Forever at 14:10 PM on 17 August 2016Climate urgency: we've locked in more global warming than people realize
tonychacher@10,
I am quite certain (almost 100%) that the evidence available to everyone following what is going on globally leads to a more correct version of your statement "Humans are not going to give up cheap, reliable power."
The statement that better explains the observations is: "Some Humans are not going to willingly give up trying to get away with obtaining personal benefit any way they can get away with, including trying to make burning fossil fuels be perceived to be a cheap, reliable power source."
The solution is social and political change of the economic game. It requires actual effective blocking of such unacceptable pursuits of personal benefit. The level of protest globally against industrial extractive unsustainable pursuits of benefit is proof that not all humans are like that more callous greedy group of deliberate cheating trouble-makers.
And a major part of the basis for that solution is the continuing effort to develop and communicate the best understanding of what is going on with the objective of advancing humanity as part of a lasting constantly improving future for a robust diversity of all life on this amazing planet.
Those who declare they will behave better when someone makes it easier and cheaper for them to behave better are part of the problem. And they deserve to be disappointed and ignored when they complain about efforts to make the damaging ways of living they developed a taste for more expensive and ultimately shut down. Hopefully, they will not respond violently to losing the freedom to continue to do whatever they please (some of them have influence over leadership of nations with nuclear first strike capability).
-
scaddenp at 12:20 PM on 17 August 2016Climate urgency: we've locked in more global warming than people realize
Tony, this site does occasionally blog on solutions eg (its too hard) but for a better source, try Jacobson et al.
There are many resources out there, but this site is primarily about responding to denier myths concerning the science.
Studies such as the Stern report dispute whether FF really are cheap - they have the appearance of being cheap because externalities like the damage to the climate are not currently factored into the price a consumer pays at the pump or on electricity bill. Puts those costs in and see if they are still cheaper than non-carbon sources. Sooner or later, humanity will have to move to other energy sources as stocks of FF become exhausted. I think future generations would prefer we move sooner.
-
RedBaron at 11:21 AM on 17 August 2016Climate urgency: we've locked in more global warming than people realize
saileshrao,
While I certainly sympathise with your choice to be Vegan, I do believe tonychachere is correct. I look at veganism as a boycott on current harmful methods of animal husbandry. Do doubt that must end, and if your boycott helps it end, I applaud you.
Do not be confused though. All the ecosystems on the planet evolved with animals. Not just animals but specifically a herbivore/predator relationship. That is why any attempt to restore agriculture to ecosystem services function again must include animals. You are welcome to boycott those animals as food too if you wish, but the farmer does need them to both feed the population and regenerate soil health (which is a mitigation solution to AGW) Without that animal impact carefully managed, yields drop and agrichemicals are needed to boost yields back up again. Then you end up back on that slow downward spiral were are on now. You might delay it a bit because the part of the industrial ag that is worst in the CAFO system. But being less bad for the biome is not the same as being good.
-
saileshrao at 10:30 AM on 17 August 2016Climate urgency: we've locked in more global warming than people realize
Tonychachere,
The data is consistent with my assertion. Please see my post on the Stanford MAHB blog here:
http://mahb.stanford.edu/blog/vegan-metamorphosis/
-
tonychachere at 10:19 AM on 17 August 2016Climate urgency: we've locked in more global warming than people realize
Dana1981,
What is the solution to knock down CO2 emissions? Humans are not going to give up cheap, reliable power. You post plenty about reasons to cut CO2 emissions, but never any solutions.
I am quite certain that at your job location, and your house that you depend on reliable power. Do you use any alternative energy as a source of power for your computing, heating/cooling needs? -
tonychachere at 10:15 AM on 17 August 2016Climate urgency: we've locked in more global warming than people realize
Saileshroa,
Do you realize that going vegan will require much more land to be cleared of forests to grow sources of nutrition not dependent on protein based agriculture?
We have some wonderful animals like chickens and goats that can forage on insects, or unfarmable vertical land, respectively. They can convert those resources to meat, eggs, milk, etc... Protein is concentrated by these animals from items that we won't, or can't eat. Veganism is the absolute wrong answer. -
saileshrao at 08:52 AM on 17 August 2016Climate urgency: we've locked in more global warming than people realize
"Pulling a significant amount of that carbon out of the atmosphere and storing it safely will be a tremendous challenge"
Regenerate forests. Per Bill Ruddiman, anthropogenic emissions in the Holocene due to deforestation activities alone is upwards of 500 GtC. That's a lot of carbon that can be sequestered safely in recovering forests once humanity goes vegan.
-
One Planet Only Forever at 08:30 AM on 17 August 2016Climate urgency: we've locked in more global warming than people realize
RedBaron,
I agree with what you have presented. But I would encourage you not to refer to it as geoengineering.
What you describe is humanity figuring out how to sustainably coexist as a part of the robust diversity of life on this planet far into the future.
Here are some other examples of Geoengineering (each one now better understood to be globally damaging and ultimately unsustainable in spite of their popularity and profitability):
- The current Industrial Agricultural practices
- The massive chopping down of rain forests to create grazing land for cattle or to grow plantations
- And burning fossil fuels
Note that each example is related to a pursuit of maximum short term profit by a portion of global humanity (in some cases a very large profit for very few humans) any way that can be gotten away with.
-
RedBaron at 14:48 PM on 16 August 2016Climate urgency: we've locked in more global warming than people realize
One Planet Only Forever,
Seems to me that there is one relatively low risk geoengineering solution. One that yes is profitable, but can't be locked in by any patents. So profitable to the general welfare and larger economies, but not exclusive to any one single individual or small group.
That potential solution is both large enough, and low enough risk to be almost pathological isanity not to do, IMHO. The solution is a fundamental change in agriculture that regenerates ecosystem services function in the soil, combined with ecosystem restoration projects like China's Loess Plateau Project (which does include an agricultural component as well). However, we do need to be serious about it. Alone these are not large enough. Everyone would need to make the changes needed worldwide. That the disadvantage. The advantage are 1 agricultural land is already managed. No need to develope a whole new untested industry. Just need to train the managers already on the land. 2 There is more than enough agricultural land world wide, even a small sequestration rate is enough. 3 Currently world wide agriculture is an emissions source, so converting it to a sink would do both, cut emissions and drawdown what's already been released. 4 Regenerative biological based systems are more profitable to the producer, because the more resources they use, the more that is left. Very different than economies based on scarcity. Economies based on scarcity are subject to boom and bust cycles. Regenerative economies are not as subject to this. Much more stable supply combined with a constant demand. 5 While agriculture of any sort can never be really considered "natural", those agricultural systems that mimic natural ecosystems by using biomimicry are taking advantage of relationships that evolved over millions of years, and thus are extremely unilikely to have unintended side effects. In fact the biggest risk would be to take out too much CO2 and start a cooling trend that is too large. However should that happen, it is well known how to fix that. ;)
-
Digby Scorgie at 14:42 PM on 16 August 2016Climate urgency: we've locked in more global warming than people realize
This article ties in nicely with the one by Bart Verheggen on inertia. It also confirms the understanding I had ever since reading "Six degrees" by Mark Lynas a few years ago — an understanding that I'd not seen mentioned at all until now.
In particular, it always seemed to me that 400 ppm of atmospheric CO2 was equivalent to about two degrees of warming at least. I couldn't understand why this prospect didn't feature in discussions of the subject. Now at last I am told that 400 ppm is equivalent in the short-term to 1.5 degrees of warming and in the long-term to about 3.0 degrees above the pre-industrial level. (Please correct me if I've misunderstood.)
The conclusion then is that a limit of two degrees is pie in the sky. Humanity has blown it — unless these mythical NETs can be made to work. But I'll believe magic when I see it.
-
barry1487 at 09:05 AM on 16 August 2016Climate urgency: we've locked in more global warming than people realize
Average of the last 12 months in the GISS surface record is 1C above the baseline (1951-1980 avg).
data.giss.nasa.gov/gistemp/tabledata_v3/GLB.Ts+dSST.txt
Global surface temps will probably continue to subside from the peak earlier in the year, but this is quite a milestone.
-
knaugle at 08:21 AM on 16 August 2016Climate urgency: we've locked in more global warming than people realize
I do think some planning has to be along the lines of what if we do nothing? How do we survive this? The idea of going to zero emissions is anathema to so many with power and money.
-
One Planet Only Forever at 05:04 AM on 16 August 2016Climate urgency: we've locked in more global warming than people realize
villabolo,
I understand many people are pursuing ways of Geoengineering on a planetary scale. And fertilizing the oceans is one of those options.
However, as an engineer I am painfully aware of how diffult it is to actually fully understand something well enough to be sure of the result. And I am talking about uncomplicated rather isolated things like knowing how strong a steel building actually will be. It is essential to understand thta a lot of experimenting is done to support the final design of a structure. And a lot of careful monitoring is required to ensure the building will perform as expected. And if necessary parts that do not perform as expected will be noticed and be able to be corrected without a major consequence. NOne of that is possible with geoengineering. The consequences would be global and a surprise. And in any engineering the ultimate objective is No Surprises. Surprises need to be restricted to the research and concept development.
In addition humanity has a lousy track recond when it comes to understanding the actual implications and consequences of any large scale interactions with Regional nature systems. So I am very reluctant to support any geoengineering, regardless of the confidence expressed by the ones promoting it as a Good Idea.
Also the push for profitability often creates resistance to actually developing a better understanding of the impacts of activities. And there is no doubt that most proponents of geoengineering concepts are pursuing potential profit, including personally patenting their ideas rather than declaring them to be public domain ideas. And it can be very easy to drum up popular support for actions that some people who are wealthy and powerful think they will personally be ablke to benefit from (including profitable actions that will allow them to continue to benefit from otherwise understood to be unacceptable actions). In many cases many others can be easily tempted to like the benefit or chance to benefit that continuing the unacceptable activity could offer (the popularity of denying the unacceptability of burning fossil fuels is a massive proof of that point).
So ocean fertilization is indeed an option. But, like all other geoengineering options, it should only be learned about to be saved up for use on a nearly lifeless plant that future humans hope to make habitable (hopefully that nearly lifeless planet won't be this one).
-
villabolo at 03:37 AM on 16 August 2016Climate urgency: we've locked in more global warming than people realize
Is ocean fertilization an option? How much CO2 can it suck out?
-
JWRebel at 00:37 AM on 16 August 20162016 SkS Weekly News Roundup #33
The article on the superBlocks was inspiring.
- I landed up staying in Europe largely because you can live here without having to own a car (no urban sprawl), that destroyer of cities. Among my best memories have been car-free days (due windless summer smog build up) when the roar of traffic subsides and people suddenly start talking to each other and their neighbours. In fact it reminded me of snow-days in Canada (too much snow to go to school or work) where everybody went to the store with a sleigh, talked to their neighbours, helped the elderly remove snow and get groceries, etc. In short, complete social transformation ...
- In urban areas, 40% of public space is occupied by cars (traffic and parking). The real estate value is huge. Where I live, everybody bitches about the costs of parking permits (about $320/year). But nobody realizes that the 10m² you are hiring is a pittance compared to what you pay for the 2m² you are sleeping on: in fact, since most housing is multi-storied, so you are (typically) paying about 3× as much to park your bed as your car, about 18× as much per m².
- The irony is that at least half the reason people need cars is to compensate for shortcomings in public transit (because everybody has cars) and to be able to escape the city!
-
RedBaron at 22:49 PM on 15 August 2016How much does animal agriculture and eating meat contribute to global warming?
@scaddenp,
The statistics you quoted are possible, however, they are significantly different in Western countries. For example, In the USA approximately a little more than 1/3rd of all beef slaughtered came from feedlots 1000 animals or larger. The majority of the rest are still feedlot finished, but on ranches and small feedlots instead. All beef cattle, whether they are grass-finished or finished in a feedlot, spend the majority of their lives grazing on grass pasture. However the vast majority finishing in some sort of feedlot, large or small, approximately four to six months. Only about 5% of beef produced in the USA remain on pasture their entire lives.
Poultry is even worse with over 97% of all broilers produced by just the top 4 industrial giants, Tyson, Pilgrim, Sanderson Farms, Perdue, never seeing the light of day a single moment of their entire lives.
Pork is similar with 97% of all pork produced in the USA raised their entire lives in confinement.
Assuming the source you quoted is correct (sometimes wiki isn't), it would have to be world statistics, not industrialized nations' statistics.
More importantly though is the vast areas of prime agricultural land being used to supply these CAFOs. Those vast acres of corn and soy etc. That is the key component of AGW. Grassland ecosystems, even including the animals grazing on them, are one of the major net sinks of both CO2 and CH4. However, modern commodity crops are net emissions sources. The "land use change" from a properly managed grazing system to a commodity cropping system used to supply CAFOs is therefore a significant cause of AGW.
-
Tom Curtis at 14:19 PM on 15 August 2016Water vapor is the most powerful greenhouse gas
"This for me is the great strength of science; the theories interlock so well and build a coherent picture."
It is also for me, and it is worth saying again and again.
-
scaddenp at 14:08 PM on 15 August 2016How much does animal agriculture and eating meat contribute to global warming?
The diagram above does not account for the industrial use of FF in agriculture under the agriculture flow. That would be under Industry and a little bit under transportation. However, if you look at breakdown of the industrial use under the end-use, you can see that agriculture of any kind (animal and non-animal) is comparitively small and does not change the conclusions of this article. On the global scale you see that Food and tobacco is 1% under industry, and 1.4% agricultural energy each.
While I wouldnt buy anything that was factory-farmed on animal ethics grounds, it is worth noting that only pork (42%) and poultry (67%) are produced on factory farms in significant quantities. (Source)
-
Glenn Tamblyn at 14:07 PM on 15 August 2016Water vapor is the most powerful greenhouse gas
Agreed Tom. They don't radiate directly from translation. But their translational energy does constitute a pool of energy that can be transferred into/out of vibrational or rotational modes and thus radiated/absorbed via those modes.
The interactions go even further. Vibration of molcules, especially in the stretching modes of vibration, will actually alter the Moment of Inertia of the molecule. In order to conserve angular momentum the rotational velocity of the molecule will be constantly changing as the molecule vibrates and the MoI varies. To conserve energy as well as angular momentum there will be a continuous interchange of energy between the vibrational and rotational modes, coupling them together to some extent. And collisions can exchange energy, momentum and angular momentum, as any snooker player can tell us.
Its fascinating how all these concepts - degrees of freedom of action, equipartition, Moments of Inertia and Quantum mechanics - all come together to give us a solid understanding of the reasons why different gases have the Specific Heat Capacities they do. And the basics of why molecules radiate and absorb.
This for me is the great strength of science; the theories interlock so well and build a coherent picture. -
bomatthew1 at 13:31 PM on 15 August 2016How much does animal agriculture and eating meat contribute to global warming?
Does this article account for all of the fossil-fuel energy that is used specifically for animal agriculture? For example, all of the fossil-fuel burned in factories specifically for factory farms and such?
-
Tom Curtis at 12:35 PM on 15 August 2016Water vapor is the most powerful greenhouse gas
Glenn Tamblyn @255, while CO2 molecules emit IR photons by giving up the energy stored in either one of three of their four possible vibrational states (see below), and microwave photons by giving up rotational energy; the energy of vibration and rotation is, on average in a gas, equal to the energy of translation along any of the three mutually perpendicular axis. That is a direct consequence of the equipartition theorem. That in turn is a consequence of the fact that any collision between two molecules can result in transfer of translational energy to rotational or vibrational energy, or the reverse. It follows that the amount of energy stored in a given vibrational state is a function of the temperature of the gas, ie, of the average translational energy of the gas.
I think this means that CO2 molecules do spontaniously radiate energy from their translational kinetic energy, but they do so through a mediated process. A hot CO2 gas sealed in a IR transparent case in a cold environement will gradually bleed away its translational energy (ie, drop in temperature) as collisions replenish the vibrational energy that is lost by spontaneous emission. It is that which Old Sage seeks to deny.
I know that we disagree on this only on whether that mediated loss of translational energy counts as "spontaneious radiation of translational kinetic energy", ie, on wording. But I think it is important to clarrify, both because Old Sage does not (I think) interpret the phrase "spontaneously radiate from their translational kinetic energy" as you do; and because readers unfamiliar with the process, or only casually familiar may be confused by that statement if the full relationship is not stated.
-
Glenn Tamblyn at 11:32 AM on 15 August 2016Water vapor is the most powerful greenhouse gas
From a previously snipped comment by old sage:
"...radiation from gases at STP, they scatter, they absorb, but most definitely they do not spontaneously radiate from their translational kinetic energy to any significant extent. All they do is convey energy from one place to another in an energy neutral fashion."
Here in a nutshell is where old sage doesn't understand what he is talking about. For his statement is correct, but incomplete. They don't radiate as a consequence of their translational kinetic energy; in fact they don't absorb in a way that impacts the translational kinetic energy either.They radiate 'from' their rotational and vibrational energy. This is the entire basis of the field of Molecular Spectroscopy which deals with emission and absorption by entire molecules as a result of rotational and vibrational transitions, in contrast with Atomic Spectroscopy which deals with electron energy level transitions within individual atoms.
Before commenting again old sage needs to do some research into the topic of Moelcular Spectroscopy. If he comments again without evidence that he has first done that research then he will have shown that he isn't interested in learning. -
John Hartz at 08:47 AM on 15 August 2016As nuclear power plants close, states need to bet big on energy storage
Recommended supplemental reading:
Nuclear fuel plant under gun to improve safety in wake of uranium buildup, explosion concerns by Sammy Fretwell, The State (Columbia, SC), Aug 12, 2016
-
sauerj at 07:24 AM on 15 August 2016Climate inertia
Tom @7: I understand everything you have written and all the math on the ATTP site, which would ultimately work down to Ts = fx(F) and he explained that a singular net 'F' comes from the RCP11 dataset. All very interesting.
Thanks for explaining the Ffeed term (feedback component). I jumped to the ATTP site right away & read it and was puzzled by the Ffeed term. Then, I read your 2nd paragraph; your explanation of Ffeed was timely. And, thanks for explaining how the Ffeed term is developed here; thus explaining that delta-forcing due to delta-humidities are not modeled directly. That's likely OK and doesn't hurt accuracy as Fd-humidity is likely near linear (w/ respect to Ts) in the temperature ranges that we are talking about.
Also, thanks for explaining the n-box detail. I assume the different time constants on Cowtan's 'model tool' correspond to the surface layer for box-1 (constant=1/yr) and the ocean layer for box-2 (constant=30/yr). And, I assume the 3-box model breaks the ocean layer into two separate boxes: possibly into 1) an upper ocean layer for its box-2 (30/yr) and 2) a deep ocean layer for its box-3 (100/yr). The 1:100 ratio here (box-1/box-3) was the same ratio used by ATTP for the heat capacity ratio.
And, thanks for heads-up on the SkS course. I did enroll for it and will start watching the course videos. You've been very helpful. Thank you!
-
Tom Curtis at 02:19 AM on 15 August 2016Climate inertia
sauerj @6:
1) The difference between the 1 box, 2 box, and 3 box models comes down to the number of time constants used. If you want more details, I believe the model is discussed in the SkS online course, which started Aug 9th but which you can probably still enroll in. Alternatively, Kevin Cowtan has in my experience always been helpful to those interested in learning more. Finally, And Then There's Physics gives the equations for a two box model here. Others have done similarly. No doubt there will be small changes in the exact form of the equations from model to model.
2) n-box models such as Kevin Cowtan's do not model feedbacks directly, and certainly not as a component of any of the forcings. Rather, the feedbacks along with thermal inertia are handled by a feedback constant (see ATTP's first equation). As a result such models are useful for giving emperical estimates of TCR and ECS, but do not demonstrate the physics.
3) I agree that the tunability of the forcings is one of the best features of Kevin Cowtan's model. I think anybody trying to argue that "it's the sun" or some other such theory should really adjust the weightings of that model to match their theory and show us why the resulting, poor fit is preferable to the good fit from the default settings.
Glad I could help.
-
sauerj at 01:11 AM on 15 August 2016Climate inertia
Tom @5. Thank you for taking the time to explain all of this to me. I understand everything you wrote. I checked out the Dr. Kevin Cowtan model and was thoroughly impressed (very easy to use and understand). Of course, I am ignorant on the details of the equational differences between the 1-box, 2-box and 3-box model variations, but that's OK. Someday, if I keep reading, I might understand what this means.
It was interesting how I could set the weighting of, say, 'Solar' to zero, just to see the difference to the 'fit'. One interesting tid-bit, the 'H2O(strato)' line is hidden exactly behind the 'BlackCarbon(snow)' line, in the forcing charts (I noted that there was 10 lines in the legend, but only 9 in the charts). But, then, when I changed the weighting of the 'H2O(strato)' line, then it appeared. One question: Is it correct to assume that rising humidities ['H2O(troposhere)'] (which would occur as a natural consequence of rising temperatures and a significant positive feedback component) is packed in the 'GHG(mixed)' line?
I was about to ask about RCP, but then found the SkS 3-part post (HERE) on that subject. I skimmed thru the whole thing; and need to return and read it in detail. This in-depth article looks amazing, and something that a person like myself should read in order to take the next appropriate step in learning.
I am a chemical engineer & very active in the local CCL chapter, which I think is the best thing out there for remediation vision, spirit and policy. ... Thanks again for your time!
-
Water vapor is the most powerful greenhouse gas
old sage @250:
"I repeat, what physical process shuts down the alleged entrapment of heat by CO2 insulation after it has reached its target temperature per concentration thickness. If you can show that, you will see the rise is snuffed out from the outset and T does not rise whatever the concentration thickness."
Ergo: Insulation has no impact on temperature, and all the producers of house insulation, thick winter clothes and so on are just making profit from a hoax.
BTW, furry mammals started that hoax about 200 million years ago, followed by feathered dinosaurs and birds, so it has obviously been going on for a very long time! -
Tom Curtis at 00:10 AM on 15 August 2016Water vapor is the most powerful greenhouse gas
KR @252, the initial decrease in IR with the increased CO2 is the "entrapment" that Old Sage refers to. I mention it again in the last sentence of the first paragraph. The rise in IR radiation to space that I mention in second sentence of the first paragraph is a consequence of the rise in surface temperature. So, not a typo, but that second sentence was poorly, and confusingly worded. Specifically, I mention that the rise in IR radiation follows the increase in CO2 (meaning in terms of time sequence) and follows on from the rise in temperature (meaning as a direct causal consequence). Clearly that makes the sentence ripe for confusion. Thank you for seeking clarrification.
-
Water vapor is the most powerful greenhouse gas
Tom Curtis - Typo? An increase in CO2 leads to a _decrease_ in IR to space, an energy imbalance that causes an accumulation of energy, an increase in temperature, until the warning climate once again emits an amount of energy equal to that coming in.
-
Ceist812534 at 12:50 PM on 14 August 2016It's cosmic rays
A new paper published in the Journal of Atmospheric and Solar-Terrestrial Physics in August 2016 finds:
"There is a significant correlation only between cosmic ray (CR) intensity (and sunspot number (SSN)) and the cloud cover of the types cirrus and stratus. This effect is mainly confined to the CR intensity minimum during the epoch around 1990, when the SSN was at its maximum.This fact, together with the present study of the correlation of LSCC with our measured CR intensity, shows that there is no firm evidence for a significant contribution of CR induced ionization to the local (or, indeed, Global) cloud cover.
Pressure effects are the preferred cause of the cloud cover changes. A consequence is that [b]there is no evidence favouring a contribution of CR to the Global Warming problem.[/b] Our analysis shows that the LS data are consistent with the Gas Laws for a stable mass of atmosphere."
-
Tom Curtis at 09:46 AM on 14 August 2016Climate inertia
sauerj @4, I have responded to your comments by subject rather than by where you located the discussion. In particular, some of the points you raise under ESS are more correctly related to ECS, and so I have discussed them under that heading:
TCR: The TCR is strictly defined only for the 1% increase per annum experiment. It approximates to the real world temperature increase because most of the initial response to a forcing occurs in the first few years and the net forcing is variable in a short to medium time span (<10 years) due to the solar cycle, volcanic activity, and the effects of ENSO and other oceanic oscillations on albedo and water vapour concentrations in the atmosphere. If, however, you had a steady increase of CO2 concentration of 0.5% per annum, the temperature achieved at the 70 year mark would be higher than that predicted from an expectation based on the TCR.
Going into more detail, I compared the BEST LOTI temperature data to a prediction based on the sum of forcings from Kevin Cowtan's two box model of global temperatures (default settings). The correlation was 0.855, the Root Mean Squared Error was 0.176, and the linear trend was 0.914 of the observed values. In a monotonic 0.5% increase we would expect the linear trend to be greater than the observed values, so the perturbations more than compensate for the difference. For what it was worth, weighting the TCR prediction based on the difference in trend (ie, eliminating that difference) increased the RMSE by 0.001, decreased the mean error (which was still negative) but increased the standard deviation of the errors.
Given that, using TCR plus ENSO as a predictor of temperatures gives a reasonable approximation, but an approximation only.
ECS: Correct, with the provisio that in the approximately 200 year time frame to reach the ECS, there will have been some albedo change from changes of ice sheets and vegetation cover - so the balance will not not be perfect. The assumption is that the change small over that time frame, so the approximation is good enough on that time scale.
As an aside, the 1.5-4.5 C range for ECS is the likely (66.6%) certainty range. According the the IPCC AR5, the probability that ECS is 1 C is less than or equal to 5%. The probability that it is less than 6 C is greater than or equal to 10%. And assuming the probabilities are symmetrically distributed, the probability that it is less than 1.5 C is less than or equal to 16.7%, while the probability that it is less thanr than 4.5% is greater than or equal to 83.3%. Here are three Probability Density Functions (PDF) that more or less satisfy those conditions:
Strictly Roe and Baker (2007) is a PDF from the time of AR4 (although it better satisfies the AR5 constraints than the AR4 constraints). However, its high probability of low values comes at the expense of substantial probabilties of very high values of ECS. Rogelj et al (2014) is a representative PDF pubished in the scientific literature, and represents a best fit to the above constraints using a log normal curve. In accomplishing the good fit, however, it violates the requirement that the probability that ECS is less than than 4.5 C be greater than or equal to 83.3%. The alternate has adjusted values to ensure compliance with the above conditions, but as a result its threshold values diverge more from the stated limits than does Rogelj et al. For what it is worth, here are the 95% confidence range, mean, median and modes for the three distributions:
Value Alternate Rogelj Roe & Baker
2.5% 1.8 0.9 1.1
97.5% 7.8 7.8 29
Mean 3.03 3.07 2.66
Median 2.56 2.53 2.20
Mode 1.85 1.74 1.65You will note that the median value (the 50:50 split) is around 2.5 C for all three distributions, and the mode below 2 C. The more reasonable climate skeptics are not wrong in expecting these lower values as the reasonable expectations (although they tend to artificially deflate the probability of higher values). In risk assessment, however, the mean value is more relevant. To exclude reasonable and dangerous possibilities from consideration, just because their probability of occuring is only 6.5% (6+ C using the alternate PDF) is unreasonable, but that is what concentrating on the median (or still worse, the mode) does. On the other hand, in popular discussion of climate risks, many people who want to take action forget that most probably (61.6% chance on alternate), ECS will be below 3 C. Of course, all of these PDFs give an artificial precession to the probability estimates.
ESS: In order to avoid overwhelming complexity, climate models do not typically vary ice sheet extent, and land cover (other then anthropogenic changes introduceds as forcings). That is justified because of the long time spans required for the melting of ice sheets. Using ESS for short term estimates is merely an artificial, and IMO misleading way of inflating percieved risk.
-
nigelj at 08:56 AM on 14 August 2016Six charts show UK progress towards low-carbon energy
One planet only forever
Burning wood is indeed compensated by growing more trees, but this is a poor quality strategy. Better to stop burning wood where possible, and use new tree planting simply to reduce total atmospheric CO2 levels.
However subsistence farmers in the third world and developing countries rely on wood just to survive, and wood pellets do emit less CO2. It would be morally absurd to expect them to stop burning wood, and the contribution of burning wood appears to be less globally than burning oil and coal. So we have to accept some wood burning in some countries, unless someone comes up with some alternative.
I agree that the western world is indeed selfish at times, and is ruled by profit and short term goals. However plenty of people realise that destabilising the planet creates problems for poor and rich alike ultimately. We just need more people to see this.
Ironically most economists recognise that profit can have a negative downside, and business and individuals cannot operate in a completely unrestrained way. Our problem is politicians, lobby groups and selfish individuals who are short sighted, and don't see the bigger picture.
-
Tom Curtis at 08:20 AM on 14 August 2016Water vapor is the most powerful greenhouse gas
Very briefly for Old Sage @250, the "entrapment" of heat by CO2 never ceases. However, following an increase in CO2 concentration, and as the temperature increases, the IR radiation from the surface and atmosphere also increase, thereby increasing the amount of radiation to space. After the temperature has increased a certain amount the amount of radiation to space returns to the the amount which balances incoming solar energy, at which point the temperature increase ceases. The temperature increase required to do that is a function not only of the reduction in radiation to space as a result of the increase in CO2 but also any further changes to the energy balance that result from the increased temperature.
This is so basic to understanding the greenhouse effect that it is stated, in one form or another, in any serious exposition of the greenhouse effect (other than those by some AGW deniers). If you did not know this, you do not understand the theory at even the most schematic level. Playing 'devil's advocate' requires actually understanding, and criticizing the theory being discussed. It also requires accepting the basic observational data. Old Sage does neither. Rather, his verison of 'devil's advocaccy' is the intellectual equivalent of a child putting their fingers in their ears, and shouting "Nah, nah, nah, nah nah-nah - can't hear you." Nobody mistakes that child for playing devil's advocate, and nor does such a response result in stimulating discussion.
-
old sage at 05:43 AM on 14 August 2016Water vapor is the most powerful greenhouse gas
As a research scientist, the most stimulating discussion was got from others playing devil's advocate - sloganeering, is that how this particular column shuts down unwelcome thoughts. No wonder I haven't bothered to tune in for years. I repeat, what physical process shuts down the alleged entrapment of heat by CO2 after it has reached its target temperature per concentration. If you can show that, you will see the rise is snuffed out from the outset and T does not rise whatever the concentration.
Moderator Response:[PS] Moderation complaint snipped. If you are research scientist, then you could try arguing like one, with accurate data and logic and especially a demonstration that you have understood the theory you are arguing against. At the moment, it is not clear that you even understand response being made to you. If you are have not read Ramanathan and Coakley 1978 then I suggest it is high time you did. Continuing to assert statements about physics of gases without backing evidence (and in defiance of well-established experimental evidence) is simply sloganeering. Put up evidence to back your assertions- otherwise your comment will be deleted.
-
sauerj at 05:31 AM on 14 August 2016Climate inertia
Tom @3. That helps; I think I get it.
TCR would be like the real temp rise (I assume that TCR could also be based on %increases CO2 other than 1%/annum as we are now increasing in the 0.5%/annum range). The TCR would be like my crude model mentioned above in @2 [Tactual = fx(CO2)], which, yes, with the right constants, would hit the RED line.
ECS is the Tequil temp. The point at which global temperature has reached the point where Qin = Qout.
And ESS is the fully integrated model with all the real-life biosphere feedbacks played out. ... But, I had always assumed that these feedbacks (all of them ... stuff like warming oceans releasing more CO2, higher humidities adding to GHG's, ice sheet albedo changes, land cover impacts, etc.) were already packed into the ECS sensitivity curve. Was that assumption wrong? Note, many SkS articles clearly indicate a sensitivity # in the range of 2.5 - 4.5C. Is this range of sensitivity #'s only referring to ECS #'s and ESS #'s are even higher?
Note: To hit the lowest point of the grey region (2.1C on a 400/290 ppm rise), the gain# would be 4.5C; and to hit the midpoint (2.6C), the gain # would be 5.6C. Maybe the range indicated on the SkS articles did go up to 6.0C (?); but I do remember that the most probable value was ~3.0C.
So I'm a little confused on the discrepancy on past SkS articles on this sensitivity # compared to this ESS curve. Note: If it's too difficult to explain this, don't worry about it; its not that important that I understand this detail. A sensitivity # of 3.0C at our current trend of carbon emissions is plenty bad enough!!!
-
One Planet Only Forever at 03:16 AM on 14 August 2016Six charts show UK progress towards low-carbon energy
JWRebel,
In addition to my previous comment, there would be a limit to the sustainable burning of wood. It would need to be limited to creating CO2 at a rate matching the CO2 taken in by new wood growth deliberately being grown as the offset of the burned wood.
Another point would be that wood pellets from harvesting deadfall that would eventually burn in a wildfire would be a sensible way to get usable energy. However, all of the renewable energy options should be competing to be regional winners without needing to compete with understood to be unsustainable damaging alternatives.
The failure of socio economic political systems to ensure that unsustainable and damaging alternatives are discouraged and are rapidly terminated whenever those are gotten away with being developed is clearly a major impediment to the advancement of humanity.
-
One Planet Only Forever at 02:41 AM on 14 August 2016Six charts show UK progress towards low-carbon energy
JWRebel, Though burning wood pellets can result in pollution other than CO2, at least the carbon in the CO2 is not new carbon added to the recycling surface environment of the planet. Fossil fuel burning simply must be terminated earlier than the free action of people in the pursuit of popularity and profitability would end the activity.
-
old sage at 00:01 AM on 14 August 2016Water vapor is the most powerful greenhouse gas
M A Rodgers please stop quibbling, the absorption of 70 w/m2 by vapourising water is a very significant proportion of the energy arriving at the surface. If you cover 1 hectare of surface with concrete and drain it, the resulting surface area presented by 1cms of rainfall shrinks from 10,000 sq m to 100 sq m as it is collected in drains. Therefore, the amount of vapour is significantly reduced.
I repeat what every schoolboy should know, that reduces cloud cover and lets more solar energy into earth's environment. The form factor and altitude of cloud formations radiate externally far more than vertically downwards.
Finally, I ask Tom Curtis to explain why when a given amount of CO2 has raised earth's temperature by t degrees - as we are asked to believe by theIPCC - it then stops retaining a single calorie of energy despite everything being in place to keep the 'blockage' of outgoing energy effective?
And please don't try to drown me in a deluge of 'off the point' rambling over radiation from gases at STP, they scatter, they absorb, but most definitely they do not spontaneously radiate from their translational kinetic energy to any significant extent. All they do is convey energy from one place to another in an energy neutral fashion.
Moderator Response:[JH] Your argumentative, word-salad responses to MA Rogers and Tom Curtis constituite sloganeering which is prohibited by the SkS Comments Policy.
-
JWRebel at 14:52 PM on 13 August 2016Six charts show UK progress towards low-carbon energy
There are some modestly positive trends here. The switch from coal to wood pellets for electrical generation (mainly based on European tax rules) is no sinecure, switching one set of problems for another, albeit with a reduction in CO² emitted — burning trees is not a global solution.
-
Tom Curtis at 00:11 AM on 13 August 2016Water vapor is the most powerful greenhouse gas
old sage @245 @246:
1) I quote again:
"Comparing the radiative rate kR (the inverse of the lifetime) to the collisional deactivation rate kM[M], provides a quick estimate that only one out of 100,000 CO2 molecules excited into the (0,10,0) by collision or absorbing a photon, will emit."
It follows that on average, where CO2 absorption equals CO2 emissions, out of every 100,000 molecules dropping from a (0,10,0) state by emission, 99,999 will have been excited to that state by collision. Your statement that "Vibrational excitation most certainly cannot arise from mutual collisions" is nonsense. Classically, there is no better way to induce vibrations in an object than to subject it to a collision. Within quantum mechanics, the vibrational mode must have a particular energy level, so that the proportion of collisions conveying that level comes into question. However, as temperature rises, the mean energy of motion of the gas molecules rises and hence the proportion of collisions having the correct energy also increases. I quote more fully:
"At 300K (27 C) ground state CO2 molecules are continually colliding with oxygen, nitrogen and other molecules. The average collision has an energy equivalent to kT where k is Boltzmann’s constant. In units usual to the field this is ~200 cm-1 (multiply by the speed of light in cm/sec and Planck’s constant to get Joules) but some of them have much more energy. A few of the energetic collisions can vibrationally excite the CO2 to the same 650 cm-1 excited vibrational level. Because collisional processes are fast wrt radiation, the number of vibrationally excited CO2 molecules can be characterized by a Boltzman distribution. At 300 K about 6% of the CO2 molecules in the atmosphere are vibrationally excited and can radiate."
Note that the Maxwell-Boltzmann distribution that governs this is a function of temperture, not of ambient radiation. The upshot is that your claim is entirely wrong.
2) Again, you are merely arguing against well established emperical data. In that, you are like the flat earthers who, in an era of international flights and GPS insist that the Earth is flat based on misunderstood scientific principles. This is made graphic by the use of IR cameras filtered to 4.2 to 4.4 microns at which wavelength CO2 absorbs and emits radiation, but H2O and other major atmospheric components do not. Using a better quality, IR filtered camera, we can see CO2 production in a variety of circumstances:
Note the CO2 coming from exhaust pipes have come from conditions of near complete darkness. Their high rate of emissions shown by their bright temperatures, therefore are almost entirely the product of thermal collisions. As a side note, the lack of visible smoke or water vapour from the stacks (1:30 on the video) confirm that they are not emitting H2O and are emitting limited quantities of soot and hence that it is primarilly CO2 that is emitting the radiation. The CO2 from peoples breath is relatively cool, and typically cooler than the background and shows up as slightly dark. Again, level of radiation is temperature dependent.
As a technical note, this sort of footage relies on wavelengths near the edge of the absorption band so that CO2 has a low emissivity other wise distant shots would be impossible. As a consequence, the low levels of radiation associated with room temperatures do not show emissions in these cameras. Using a 15 micron filter, they would but so also would H2O.
3) Each meter cubed of dry air at standard pressure and 300 K results in the emission of about 7 Joules of energy per second, but a stack of such cubes will result in absorption of some of the emissions which limits the total amount transmited. At the the 15 micron emission peak for CO2, such absorption may well occur within the first meter, so that the total amount leaving each cubic meter may be a little less than the 7 joules.
More importantly, the CO2 emits the energy, it does not generate it. It is only able to emit the energy because it is continuously absorbing an equivalent amount of energy from thermal radiation and collisions. Therefore it cannot heat a room anymore than the high emission from room temperature walls will heat a room. In short, the laws of thermal emission do not violate the laws of thermodynamics (and if you think they do, move your discussion to the Second Law of thermodynamics thread).
-
MA Rodger at 00:00 AM on 13 August 2016Water vapor is the most powerful greenhouse gas
old sage @246,
I'm disappointed by your responses. What you're telling me is that you were wrong to write @340 that "according to wikipedia, the average solar energy 24 hrs/day per unit area is 141 w/m2." In itself this is fine. Who does not make unfortunate mistakes from time to time? But you sadly dodge any explanation/apology. That is poor do's.
My reason for asking for a link was that it would provide us with the same hymn-sheet to sing from. As it is you provide no link and instead @244 provide the vaguest of description - "The average surface energy per m2..." and attach the vaguest of values to it - "...is of the order 150w."
Can I cut through your reticence and suggest that the graphic above @236 provides a source of this data. The 1360/4 = 340W/sq m of TSI you sign up to @ 245/46 is given there. We also have the average solar energy absorbed at the surface "of the order of 150w" = 161W/sq m. And your 70W/sq m is also within the given range of 70-85W/sq m. (I should point out that 99cm of precipitation would require more than 70W/m sq to evaporate from the surface unless the evaporating water was at 100ºC, which is why the graphic gives a range running higher than your 70W/sq m.)
So are we happy with the graphic @236?
-
old sage at 22:21 PM on 12 August 2016Water vapor is the most powerful greenhouse gas
M.A. Rogers - oops 1360/4 w/m2, not kw.
-
old sage at 22:08 PM on 12 August 2016Water vapor is the most powerful greenhouse gas
Just a couple of points of clarification:
M.A. Rogers - the gross incident energy is of course 1360/4 kw/m2. But I agree, the Google results are somewhat suspect and need further inspection.
Tom Curtis: The 6% of excited molecules you allege must come about from externally derived illumination. Vibrational excitation most certainly cannot arise from mutual collisions. It's a question of the difference between absorption and emission, your number, if true, varies with the strength of source rather than temperature of the gas.
-
old sage at 20:03 PM on 12 August 2016Water vapor is the most powerful greenhouse gas
M.A. Roger- do a google search and you will find the average surface energy per m2 is of the order 150w. This is to compare like with like for average surface rain fall of 99cms taking up 70w/m2.
Tom Curtis - 7w /m3 for radiation by CO2, 40 times as much H2O vapour of similar characteristics in the air means 280 w/m3. My living room is 90m3 so why do I bother heating it. Have you even considered how the tiny weight of CO2 in a m3 could generate 7 watts?
This column needs to be renamed so as to include surreal.
-
stevecarsonr at 15:34 PM on 12 August 2016Rejection of experts spreads from Brexit to climate change with 'Clexit'
Tom,
Thanks for the paper. It doesn't look like it made it through peer-review - well, I can't find it published anywhere. I was looking so I could see the figures referenced (that don't appear in the draft online paper).
Interesting paper. The question posed is an good one, but more interesting would be the comparison with a naive forecast, i.e. the skill. So, for example, if the UK has outperformed Germany for 5-years in a row, then the sensible naive forecast is to say "UK will outperform Germany this year". When you win, you get a tick. As far as I can see the paper says "yes, win = tick". But like with the naive forecast which says "the weather tomorrow will be the same as today" you don't get a tick for skill unless you beat the naive forecast. That is, you need to have skill.
My weather forecasting has a brilliant track record, but it has no skill over the naive forecast.
How good are forecasts at predicting a change? For example, when we look at forecasts of GDP growth, the "forecasts" are great when the economy has been growing at 1-3% each year and the next year the growth is 1-3%. Hurray for the forecast!
When last year was 2% and next year is -1%, the forecasts (mostly) turn out to be rubbish. Likewise, when last 3 years were -1%, -2%, -3% and next year is +5% the forecasts turn out to be (mostly) rubbish. Not all of them though. A few are always right. Like many people visting the casino, there are always a minority that make money. Just different ones each time.
How were the forecasts of the UK not joining the Euro vs the countries that did join the Euro?
UK was predicted to do worse than the Euro block. How did that one turn out?
Some papers predicted very large growth in "intra-Euro" trade based on economic fundamentals. The results were basically - slight improvement vs the past. Compared with forecast, awful.
I'm happy to learn more here about economics forecasting: i) the comparison with reality; ii) the skill. A few more papers, even ones that are published in peer-reviewed economics journals will be appreciated.
1. Some examples of predictions of gloom in the midst of hope that were right - economy tracking up, majority of economists said "it's going to be real bad next year" and they were correct.
2. Some examples of predictions of hope in the midst of gloom that were right - economy in recession, majority of economists said "next year will be great" and they were correct.
But I'm sure my anti-intellectual bias in not placing faith in economics forecasting will be easy to demonstrate.
Prev 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 Next
