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Post by poitsplace on Sept 20, 2009 13:29:31 GMT
Science can explain the magnitude of the warming through orbital forcings with positive ice-albedo, water vapor, co2 and methane feedbacks.
That is a load of crapIt is the only existing and quantified explaination for glacial/interglacial transitions. We know the orbital forcings are far too weak, so a high climate sensitivity is needed to explain it. This backs up my point that a high climate sensitivity is required to explain the climate response to such a weak forcing. There's nothing here mentioning a significant forcing of the Earth's climate. What we have is like I said last post. Current understanding is that climate forcings over the past million years are too weak alone to explain the large temperature variation over this time period. The only credible explaination is overall strong positive feedback in climate, ie high climate sensitivity. The proposed cosmic ray/cloud mechanism is a positive feedback mechanism and the hypothesis there is absolutely that Earth's climate has a high climate sensitivity. The best explaination, really the only quantified one, is this positive feedback is a combo of components such as ice albedo and greenhouse gases. Perhaps cosmic rays-clouds are another positive feedback, but whether that is the case including their magnitude remains to be seen. And the elephant in the room, socold is that there's a physical stop at either end of the process. The temperatures don't go much higher than a certain level or much lower. This is all perfectly explained by the absurdly high feedback rates suggested by people such as yourself. What you don't seem to be able to get through your head is that albedo and water vapor feedback is virtually non-existent right now in the warming direction. Right now water vapor content in the atmosphere is incredibly high and it temporarily ties up over 1/4 of the energy received from the sun. Ice albedo is at a minimum aside from the antarctic and greenland...which we're WAY far away from seeing melt. The high water vapor content means most of the world is a lush, green paradise. During the ice age, things change DRASTICALLY. Most of north america and 1/4 of europe are covered in ice. Most of the remainder of the land is actually covered in tundra or desert, both of which have substantially higher albedo. The climate, socold...is INCREDIBLY insensitive to these fluctuations when you consider all these changes, along with the milankovich cycles...probably hack over 10% off of earth's energy budget.
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Post by socold on Sept 20, 2009 14:09:24 GMT
And the elephant in the room, socold is that there's a physical stop at either end of the process. The temperatures don't go much higher than a certain level or much lower. This is all perfectly explained by the absurdly high feedback rates suggested by people such as yourself. What you don't seem to be able to get through your head is that albedo and water vapor feedback is virtually non-existent right now in the warming direction. For ice albedo there is a decline but not a total stop. There will be snowlines around the world at some time of the year that can be pushed back by warming for a long time before it all disappears. Water vapor feedback also won't just stop. This is further backed up by the idea that the eemian reached 2C warmer than present and that even warmer conditions were reached further back. Milankovich cycles produce up to 0.7% fluctuation in the solar forcing (only about 10 times more than over the solar cycle) which isn't enough to explain the magnitude of the glacial/interglacial temperature variation unless those small orbital forcings are being amplified by the climate system itself. Ie net positive feedback and high climate sensitivity are very strongly suggested by the paleo data and of course theory also strongly suggests it. What skeptics needed was a nice paleoclimate history that showed very little variation (eg suggested low climate sensitivity) and no abrupt and rapid climate shifts (eg suggested stable climate without tipping points). But the actual paleoclimate record shows both shows large variation in temperature and shows abrupt and rapid climate shifts. This is why I found it odd that skeptics would cite the variation and abrupt changes in the paleo record as an argument against the risk of AGW when in fact it is evidence for such risk.
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Post by nautonnier on Sept 20, 2009 15:07:08 GMT
SoCold you misstate Sentient's argument He made several arguments. I addressed the key one which centered around recent climate being irrelevant and natural because it is not "anomalous" That was another argument. It is also flawed. You can't conclude co2 rise cannot cause warming just because something else can cause warming. It defies belief that people would even suggest that as an argument. "Forest fires are caused by lightning strikes, therefore they cannot be caused by gasoline" "
That was another argument. It is also flawed.
You can't conclude co2 rise cannot cause warming just because something else can cause warming. It defies belief that people would even suggest that as an argument.
"Forest fires are caused by lightning strikes, therefore they cannot be caused by gasoline""SoCold - what he was actually SAYING was that there are clear occasions when there was a NEGATIVE correlation between global temperatures and CO 2: temperatures dropped fast with CO 2 concentrations remaining high . In your analogy that is like finding that pouring gasoline on a forest fire puts it out. But of course CO 2 today is _different_ CO 2 isn't it, because some of it comes from SUVs
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Post by icefisher on Sept 20, 2009 16:46:48 GMT
The only credible explaination is overall strong positive feedback in climate, ie high climate sensitivity. The proposed cosmic ray/cloud mechanism is a positive feedback mechanism and the hypothesis there is absolutely that Earth's climate has a high climate sensitivity. LOL! Its always fun to argue with somebody who likes to play semantic games. So the cosmic ray/cloud mechanism is a positive feedback. Using that as a standard. . . .CO2 forcing is just a feedback to the primordial stew.
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Post by socold on Sept 20, 2009 16:53:09 GMT
The only credible explaination is overall strong positive feedback in climate, ie high climate sensitivity. The proposed cosmic ray/cloud mechanism is a positive feedback mechanism and the hypothesis there is absolutely that Earth's climate has a high climate sensitivity. LOL! Its always fun to argue with somebody who likes to play semantic games. So the cosmic ray/cloud mechanism is a positive feedback. Of course it is, it's based on amplifying the solar forcing. If feedbacks are net negative however as many skeptics claim this shouldn't be possible, the solar forcing would be dampened rather than amplified.
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Post by socold on Sept 20, 2009 16:57:18 GMT
SoCold - what he was actually SAYING was that there are clear occasions when there was a NEGATIVE correlation between global temperatures and CO 2: temperatures dropped fast with CO 2 concentrations remaining high. As I would expect would happen if there's a sudden strong negative forcing. Look at Pinatubo for example. Temperature drops suddenly due to the eruption while co2 doesn't. That doesn't tell us co2 doesn't cause warming.
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Post by nautonnier on Sept 20, 2009 17:08:18 GMT
SoCold - what he was actually SAYING was that there are clear occasions when there was a NEGATIVE correlation between global temperatures and CO 2: temperatures dropped fast with CO 2 concentrations remaining high. As I would expect would happen if there's a sudden strong negative forcing. Look at Pinatubo for example. Temperature drops suddenly due to the eruption while co2 doesn't. That doesn't tell us co2 doesn't cause warming. So what is your explanation for the negative correlation in the _OTHER_ direction - low CO 2 / GHG and a rapid climb in temperature?
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Post by poitsplace on Sept 20, 2009 17:09:42 GMT
Milankovich cycles produce up to 0.7% fluctuation in the solar forcing (only about 10 times more than over the solar cycle) which isn't enough to explain the magnitude of the glacial/interglacial temperature variation unless those small orbital forcings are being amplified by the climate system itself. Ie net positive feedback and high climate sensitivity are very strongly suggested by the paleo data and of course theory also strongly suggests it. What skeptics needed was a nice paleoclimate history that showed very little variation (eg suggested low climate sensitivity) and no abrupt and rapid climate shifts (eg suggested stable climate without tipping points). But the actual paleoclimate record shows both shows large variation in temperature and shows abrupt and rapid climate shifts. This is why I found it odd that skeptics would cite the variation and abrupt changes in the paleo record as an argument against the risk of AGW when in fact it is evidence for such risk. Ok, obviously your brain shuts down when you get too many concepts. Let's just concentrate on ice albedo feedback. Not present in that picture is the fact that in the hemisphere experiencing winter during the glacial period the ice extended to within as much as 50 degrees of the equator. During the northern summer when all that northern ice was getting full sun there was STILL more ice albedo from southern hemisphere ice than there is today from all the arctic ice during the summer. Between the ice sheets and the ice going so much closer to the equator...there was well over ten times the ice albedo feedback possible during the glacial period.
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Post by icefisher on Sept 20, 2009 17:26:33 GMT
LOL! Its always fun to argue with somebody who likes to play semantic games. So the cosmic ray/cloud mechanism is a positive feedback. Of course it is, it's based on amplifying the solar forcing. Now we are getting moronic. With your logic, one can argue atmospheric CO2 is a feedback in that it dampens earthshine.
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Post by socold on Sept 20, 2009 18:25:46 GMT
As I would expect would happen if there's a sudden strong negative forcing. Look at Pinatubo for example. Temperature drops suddenly due to the eruption while co2 doesn't. That doesn't tell us co2 doesn't cause warming. So what is your explanation for the negative correlation in the _OTHER_ direction - low CO 2 / GHG and a rapid climb in temperature? A sudden strong positive forcing.
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Post by socold on Sept 20, 2009 18:28:35 GMT
Milankovich cycles produce up to 0.7% fluctuation in the solar forcing (only about 10 times more than over the solar cycle) which isn't enough to explain the magnitude of the glacial/interglacial temperature variation unless those small orbital forcings are being amplified by the climate system itself. Ie net positive feedback and high climate sensitivity are very strongly suggested by the paleo data and of course theory also strongly suggests it. What skeptics needed was a nice paleoclimate history that showed very little variation (eg suggested low climate sensitivity) and no abrupt and rapid climate shifts (eg suggested stable climate without tipping points). But the actual paleoclimate record shows both shows large variation in temperature and shows abrupt and rapid climate shifts. This is why I found it odd that skeptics would cite the variation and abrupt changes in the paleo record as an argument against the risk of AGW when in fact it is evidence for such risk. Ok, obviously your brain shuts down when you get too many concepts. Let's just concentrate on ice albedo feedback. Not present in that picture is the fact that in the hemisphere experiencing winter during the glacial period the ice extended to within as much as 50 degrees of the equator. During the northern summer when all that northern ice was getting full sun there was STILL more ice albedo from southern hemisphere ice than there is today from all the arctic ice during the summer. Between the ice sheets and the ice going so much closer to the equator...there was well over ten times the ice albedo feedback possible during the glacial period. I don't see what your point is. I said the ice albedo effect reduces with time but doesn't simply stop at the present day. Your picture and text backs that up.
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Post by nautonnier on Sept 20, 2009 20:05:24 GMT
So what is your explanation for the negative correlation in the _OTHER_ direction - low CO 2 / GHG and a rapid climb in temperature? A sudden strong positive forcing. That is a cop out response - what do you suggest a negative volcano that sucked perhaps?
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Post by socold on Sept 20, 2009 20:13:34 GMT
An increase in absorbed solar radiation for example
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Post by nautonnier on Sept 20, 2009 20:21:24 GMT
An increase in absorbed solar radiation for example And in the absence of *CO 2* whatever could possibly have cause that increased absorption?
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Post by socold on Sept 20, 2009 20:37:41 GMT
co2 doesn't absorb sunlight anyway.
How about an increase in solar output?
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