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Post by dontgetoutmuch on Feb 6, 2009 20:14:19 GMT
Steve, oh man that is a nasty self inflicted wound ya got there... When you wrote: "Other evidence of positive feedbacks is the large swings in climate that have occurred in the past such as during the ice age cycle. The changes in greenhouse gas levels, the albedo and the Milankovitch cycles are nowhere near enough to explain the ice ages." Let me see, your argument is that C02 is going to kill us all, just like... well albedo can't, uhhh how about Milankovitch cycles... no? Well it must be those pesky greenhouse gasses, I don't know, dinosaurs breaking wind while driving their very large SUVs or something. NO??? Wait a minute what was your position again? Steve's take on AGW -> C02 can't cause climate change even though it does. Dude, get a band aid on that thing. :-) No bandaid required. You've misunderstood. It was a discussion about feedbacks to an initial source of warming. Some of the feedbacks are probably independent of the inital cause of warming (be it solar, albedo changes or greenhouse gases). The fact that the climate was very sensitive to changes during the ice age is evidence that it may be very sensitive to changes due to CO2 warming. Once again we are back to feedbacks and sensitive climate. The fact that the climate changed dramatically eons ago is not proof of ANYTHING. Except that climate does indeed change, sometimes dramatically. Earthshaking I agree. On the other hand, don't you think it is a stretch to say that the climate changed, and since we don't know why it must be PROOF that feedback and sensitive climate are the reason. I have a hypothesis that explains the ice age. Are you ready? A long time ago an alien spacecraft flew by the earth. The aliens in question thought that earth would be a great place to ski. But alas there was not enough snow. To fix the problem, the aliens put up a sunshade that blocked all the sunlight from the earth. Imagine their surprise when the planet failed to cool. After further study it was determined that the cause of the failed cooling was that the future inhabitants of the planet had determined that the sun did not drive the planets climate, instead certain trace gasses were keeping the planet hot. Using unfathomably advanced technology the aliens overcame this difficulty and went skiing. When they were done. They left. And powered down their device. Thus causing the planet to slowly warm. Due entirely to the presence of the greenhouse gasses, of course. Subsequent ice ages were caused by the aliens returning to ski. I have computer modeled this extensively and nothing that has ever happened or will happen is incompatible with my results. Should my premise or the results of my research come under attack by anyone. We can be sure that they are funded by the aliens themselves. Now I understand that in the old days, I would be required to go through the tedious exercise of validating my model and maybe testing my hypothesis or god forbid sharing my source code, but that is old school. All of the hip scientists such as myself use the Post-Normal science concept which eliminates all that unnecessary work. One last item. I have learned that the aliens will be returning to ski in a hundred years or so, I can stop them from plunging the planet into another ice age but it’s gonna cost you and you have to start paying now! P.S. Look at that, time for my meds. ;D
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Post by jorgekafkazar on Feb 6, 2009 20:31:56 GMT
One last item. I have learned that the aliens will be returning to ski in a hundred years or so, I can stop them from plunging the planet into another ice age but it’s gonna cost you and you have to start paying now! P.S. Look at that, time for my meds. ;D LOL! Where do I send my check? And do these noises in my head bother you?
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Post by dopeydog on Feb 6, 2009 22:45:20 GMT
So what would invalidate agw?
They "claim" that if the climate gets warmer that proves agw.
If the climate gets cooler that validates agw.
If the climate gets undefinably more violent that validates agw.
Floods validate agw.
Droughts validate agw.
Apparently only absolutely average weather with out interruption for some undefinably long length of time would disprove agw....and then look out for attacks on the validity of the average.
This is not science...unless perhaps Campbell soup science...you know "low sodium natural sea salt".
Obviously if this horrid CO2 had a "natural" source other that at the hands of man or man's cow, it wouldn't be altering the climate.
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Post by poitsplace on Feb 6, 2009 23:28:38 GMT
No bandaid required. You've misunderstood. It was a discussion about feedbacks to an initial source of warming. Some of the feedbacks are probably independent of the inital cause of warming (be it solar, albedo changes or greenhouse gases). The fact that the climate was very sensitive to changes during the ice age is evidence that it may be very sensitive to changes due to CO2 warming. It shows NO signs of significant sensitivity to CO2...otherwise CO2 levels wouldn't take the better part of 1000 years to change and wouldn't take THOUSANDS of years to drop again, long after the planet has plunged deep into the depths of a new ice age. You know what you can take away from the ice core records? That the earth currently has one stable state (ice) and a warmer, less stable state. The next higher stable state seems to be total deglaciation. The problem with AGW proponents predictions about feedbacks is that as the states are stable for a reason...and that means they're probably in a sort of feedback "well". The feedbacks toward warming or cooling are negative in this temperature range (more negative toward warming, actually from the behavior) The only reason anyone ever suspected there might be strong feedbacks is because the temperature was rising faster in the 80's and 90's than CO2 increases suggested. The only reason they thought that was because quite frankly, normal people...even intelligent people...aren't actually very good at dealing with complex systems. Otherwise they'd have seen the blatantly obvious cyclic climate shifts and realized where all the extra "forcing" was coming from. The majority of the warming in the latter half of the 20th century is almost certainly natural. To suggest otherwise would be like suggesting that just because temperatures went up in the morning, they'd be above boiling point on the following day. The only runaway affect we're seeing in climate science now is in the predictions.
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Post by socold on Feb 7, 2009 3:51:11 GMT
We've had the warming for 70 freaking years, we've had ice melt...temperatures seem perfectly able to drop again with the PDO and solar forcing. There's no evidence that this is happening Cooling isn't evidence against positive feedbacks. When you have cooling the positive feedbacks work the opposite way and amplify the cooling. In any case the increase in co2 forcing in in the shorter time period 1980 to 2007 is greater than the in the longer time period 1940 to 1980. Additionally the lag time in temperature response causes part of the 1940 to 1980 forcing to "have effect" later than that. About 15-20% of the total co2 forcing over the 20th century occured in that time frame. Noone is arguing that co2 forcing must be necessary for such increases. However it seems co2 forcing is required to explain the recent warming. With only natural forcings not all the warming can be explained (obviously, as co2 must have contributed) Hence why there are error bars on the diagram. Notice, as error bars do, they go both ways. Uncertainty makes the best case scenarios better, but also the worse case scenarios worse: The high tech energy sources are miles from fossil fuels. And as soon as people start using them more, the price of fossil fuels just drops enticing people back.
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Post by FurryCatHerder on Feb 7, 2009 5:42:41 GMT
If you think that AGW requires a "runaway" water vapor feedback to occur, you don't understand the basic physics of AGW.
Imagine a pot of water sitting on your stove on a medium flame. The water reaches a steady temperature after some amount of time. That represents the current global average temp. Now, give the knob a slight twist to turn it up. After some period of time, the water will reach a new equilibrium temperature. That's the "new" warmer temperature.
While you are doing this, look for the signs of convection currents in the water. Each convection current starts as an area of high temperature water that rises from the bottom and cools at it ascends, with cooler water replacing it. That's the non-uniformity of the weather.
There's no need for a "runaway" water vapor feedback to make the pot warmer, just a need for an increase in energy input. The amount of heat lost by the pot to the kitchen air increases with the temperature of the water, just as the amount of energy the earth radiates into space increases with temperature ("black body radiation"). This is what prevents runaway -- rising global temperatures are themselves a form of "negative feedback".
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Post by poitsplace on Feb 7, 2009 5:52:13 GMT
Right, so we're feeling those massive increases now, are we? Ten years without any warming with indications it's going to cool...and NOW we're feeling the REAL warming from the CO2. And yet SOMEHOW, even though you assert that natural forces simply can't make it warm as much as it has...that 15-20% somehow ended up having a warming trend with pretty much the same warming as the most recent one. Hey wait, didn't you just say the warming was delayed? Again I have to ask...why the heck would you bring up this period in an AGW discussion. Ah, then name off all the forcings. you said "with only natural forcings not all the warming can be explained", so you must have full working knowledge of all forcings. What are they? Were you aware of the behavior of the outter atmosphere before it dropped to be able to say that? Did you know about the PDO before it was published? Is this actual knowledge or more of a "well, I don't think so" sort of thing? I seriously question those figures even WITH the error bars. For instance, land use shows cooling yet everywhere man has any impact at all...the temperatures are obviously higher than the surrounding areas. Halocarbons...measured in parts per trillion, I'm seriously doubting that being on the stronger end of a logarithmic increase. The sun's contribution is also assumed to be entirely based on it's TSI...something we know is not correct. There are significant changes to the type of energy output and the atmosphere has recently shown a massive shift in altitude (not unlike the atmosphere did during the previous (but not TOO low) cycle ending in the 70's. (except of course the current drop is far, far more pronounced) And then back to the previous warming period...so you're saying that there's been more warming than can be explained but we had that much before. But there was 15-20% as much CO2 during that period so it should have warmed...only the increase lags so we didn't. And then somehow warming in the 80's and 90's was too much to be explained by natural forces (although it's happened before) and therefore there must be something like aerosol cooling. Let me see if I've got all this straight, it's warmed this much before, but that was when we had much less CO2 added that didn't contribute to the warming because there's a delay before warming. The recent warming though (which is roughly equal to the previous warming) is so great that the newer warming can't be explained naturally. BUT at the same time this warming that's too great to be accounted for is too weak to be correct so the earth must be cooled by something else. And finally, due to a delay we're feeling the strongest affects of this warming only now...as the earth cools. Do you see why we call this junk science? At least you got that first part right. There's no way most alternatives are ready to provide a major chunk of our energy. But the costs of alternatives have just kept dropping. They will soon be viable, just not now. Crippling the economy by forcing it to adopt expensive alternatives will just slow down the speed with which we can develop economically viable alternatives.
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Post by donmartin on Feb 7, 2009 6:55:00 GMT
"...we're running out of fossil fuels, especially liquids." Well, first off, fossil fuels are not liquids; no more than your corner store is where milk comes from. Incredible. And the idea that we're "running out" of "fossil" fuels, is a promotion right out of the de boers shortage of diamonds deal. Fact: Canada has sufficient petroleum reserves to supply the world for 500 years at the world's increasing rate of consumption. Of course, that knowledge would in no way contribute to the 43 billion dollar profit which Mobil made last year. Or was it in the last quarter. The generally accepted, but fantastical ravings of educated idiots will lead to a well-deserved and very cold, cold ending to our young civilization. I am older and will soon pass beyond the current lunacy. It is however, so sad to see the inculcation of popular sado-masochism in the masses. Let's have a depression. So very sad. Our human progress may very well die with such words as "absorption coefficient of gases compared to liquids" on its lips. So very sad.
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Post by kiwistonewall on Feb 7, 2009 11:22:39 GMT
It would be nice if in addition to having a go at me, people would also have a go at the obviously faulty saturation argument. ............ I now await the "Well if you are trying to kill poor people with your stupid business destroying eco-theories you need better evidence" reply. Steve: I use a low emission fuel in my car, grow vegetables without chemical pesticides, want to be a good steward of the planet, am concerned over bio-diversity, and think co-operatives are a good way of running things. I don't want to attack you in any way whatsoever. You may be paranoid, but I, personally, am not out to get you. I am a physical chemist. The "saturation" argument is based on standard absorption spectroscopy - a field I studied at post-grad level. I also studied Atmospheric Photochemisty at post grad level. I can be fairly certain that I am more qualified to make an assessment of this area than you and most Climate modellers and Hindu Economists are. (Nothing against Hindu economists, but they shouldn't be running the IPCC) The fact is that there is more than enough CO2 to scatter (not "trap") the IR energy. Adding more just increases the path taken, but has no additive effect that could ever be measured. Once every photon in the relevant spectral range is absorbed, the effect cannot increase. It can never increase above the less than 50% return figure, since the scattering is equally outwards as much as inwards. The effective capture works equally both ways. It is very simple when you grasp what is happening at the molecular level. EVERYTHING that works to increase the capture of IR, works in all directions, including doppler spreading. There can never be more than just less than 50% returned to the earth, the rest escapes to space. NOTHING can change that. It is the Sun, via many subtle effects we are yet to truly understand, and the sooner the better we get on with that research. The Sun may indeed fry us one day. It has made a good attempt in the past few decades, and that heat energy stored in the oceans will take some time to exit the system. If the Sun roars back into activity, then we will warm, but at present, it is slowing down. There are many things we NEED to do to address critical environment concerns. Real needs to address disease, hunger, biodiversity and the problems caused by mindless greed of some multinationals. But adding destructive taxation and totalitarian practices in government isnt the solution.
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Post by steve on Feb 7, 2009 14:42:52 GMT
Kiwi,
I sincerely hope that I have never said that CO2 "traps" infrared.
The surface and all levels of the atmosphere are emitting and absorbing infrared.
A substantial proportion of the IR spectrum is quickly reabsorbed at lower levels.
Emission from a given location is proportional to the fourth power of the temperature and is in all directions. Therefore, at the higher and colder levels of the atmosphere there is less emission.
By uniformly doubling CO2 concentrations you decrease the mean free path of an emitted photon throughout the atmosphere.
This means that from any given layer of the atmosphere from which a proportion of IR is escaping to space, the proportion reduces.
But because the higher layers are colder, they emit less, and cannot balance out the reduced proportion of photons escaping from below.
#
As a second way of thinking about it. If you view the earth with infrared eyes (using regions of the spectrum that are reasonably well saturated), then the earth will look foggy. The temperature of the fog will be the temperature of the depth of atmosphere from which much of the radiation is escaping.
Talking technically for a moment, a rule of thumb would be that you are observing the atmosphere at a level where the optical depth is 1.
If you double CO2, the fog gets slightly thicker, and you can see less deeply. By seeing less deeply you are seeing colder layers. These layers emit slightly less energy because they are colder.
The difference in temperature will be about 1C, equating to 4W/m^2.
Precisely this sort of calculation is done when observing any hot gaseous object, including the sun.
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Post by steve on Feb 7, 2009 14:48:25 GMT
No bandaid required. You've misunderstood. It was a discussion about feedbacks to an initial source of warming. Some of the feedbacks are probably independent of the inital cause of warming (be it solar, albedo changes or greenhouse gases). The fact that the climate was very sensitive to changes during the ice age is evidence that it may be very sensitive to changes due to CO2 warming. Once again we are back to feedbacks and sensitive climate. The fact that the climate changed dramatically eons ago is not proof of ANYTHING. Except that climate does indeed change, sometimes dramatically. Earthshaking I agree. On the other hand, don't you think it is a stretch to say that the climate changed, and since we don't know why it must be PROOF that feedback and sensitive climate are the reason. You're missing the point. It is about disproof, not proof. It is not *unreasonable* to assume that this is *evidence* not *proof* of a positive feedback. This evidence supports current models and observations. It does not *prove* them true. But importantly, it doesn't *disprove* them. Yep! I'll start reading....NOW! B****r. I thought you were going to be serious
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Post by steve on Feb 7, 2009 14:53:28 GMT
What invalidates AGW?
Many things invalidate aspects of AGW. There has been a range of predictions of the impact on hurricane strength and level. There have been variations in temperature predictions. There is still not a consensus on sensitivity, nor on the rate that ice sheet melt will add to sea level rise predictions.
So it depends which aspect of AGW.
Possibly you refer to the prediction that AGW will be sufficient to cause damage to the world's infrastructure such that it would be better to take action to reduce levels of CO2 emissions.
But if you were selfish you might only be concerned with its impacts on your back yard.
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Post by socold on Feb 7, 2009 19:39:54 GMT
Right, so we're feeling those massive increases now, are we? Ten years without any warming with indications it's going to cool...and NOW we're feeling the REAL warming from the CO2. The last 10 years do show warming: www.woodfortrees.org/plot/wti/from:1999/plot/wti/from:1999/trendThe Early 20th century was when the solar increase had it's main effect. However since the 50s solar output has been virtually flat. Here: You can seriously question all you want, just as creationists seriously question a 4.5 billion year old Earth. But what I posted is what the science says. It might be wrong, but that's a tough argument for a layperson on an internet forum to make. No we don't know it's not correct. If we knew of some other forcing it would be included. The fact it isn't on the table is because no such other-solar influence has been demonstrated and quantified to require adding one. Something like www.globalwarmingart.com/images/thumb/a/a2/Climate_Change_Attribution.png/436px-Climate_Change_Attribution.pngis why recent warming cannot be explained without including greenhouse gas rise.
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Post by jimcripwell on Feb 7, 2009 21:47:19 GMT
socold writes "No we don't know it's not correct. If we knew of some other forcing it would be included. The fact it isn't on the table is because no such other-solar influence has been demonstrated and quantified to require adding one."
and
"is why recent warming cannot be explained without including greenhouse gas rise."
But by the same token, AR4 in Chapter 2.7 fails to prove that, other than a change in the solar constant, no other solar effects exist. The IPCC merely cherry picks the available information, and leaves the impression that it has proved that there are no other solar effects, but it has not done so, nor do it claim to have done so. So it is simply wrong to conclude that only greenhouse gases can account for the recent warming.
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Post by poitsplace on Feb 7, 2009 22:56:22 GMT
The Early 20th century was when the solar increase had it's main effect. However since the 50s solar output has been virtually flat.
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