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Post by socold on Apr 13, 2009 20:16:51 GMT
socold "Exactly, what temperature does in the next 10 years will make all the difference. I fully intend to change my mind if temperature over the next 10 years declines or stays flat short of a large volcanic cooling occurring or the Sun going staying low." So if volcanic activity increases due to the solar minimum as has happened before you Won't change your mind! If the Sun Goes low (already) stays low (probable) then you Won't change your mind! ROARS WITH LAUGHTER!!! This thread has been dragged back to life 6 months after the last post. Interestingly though, I recently made a similar post and thought more about how to explain the fact that cooling world wouldn't necessarily disprove AGW. Let me give it in the form of a example scenario where a deep solar minimum and volcanic events suddenly appear: And as a result we get something like this (values are for example purpose only): +0.5C from co2 -0.5C from some kind of maunder minimum -0.5C from a sudden burst of multiple volcanoes Add them all up, and you get a net cooling of 0.5C. Now you see why a cooling wouldn't necessarily disprove AGW. Because that first line exlicitly states AGW has occured. The moral of the story is that simply looking at the net change of -0.5C doesn't tell you how much warming co2 caused. You need to actually split the temperature change into it's components. Letting co2, volcanic forcing and solar output all change signifcantly at the same time is like performing an experiment and letting all the variables change. It's more difficult to determine just what the co2 does if you mask it with other effects. It's far easier to rule out the contribution from co2 if only co2 significantly changes and still temperature doesn't rise.
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Post by hilbert on Apr 14, 2009 0:30:25 GMT
I thought that Hansen had stated that there was a net heat flux of (?) .8 W/m^2 (I don't recall the number). If solar minimum and El Ninos etc. mask this, then that heat *must*, according to Hansen, be going somewhere. Where?
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Post by hilbert on Apr 14, 2009 0:32:08 GMT
Sorry, that should have been La Ninas...
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Post by magellan on Apr 14, 2009 2:05:50 GMT
socold "Exactly, what temperature does in the next 10 years will make all the difference. I fully intend to change my mind if temperature over the next 10 years declines or stays flat short of a large volcanic cooling occurring or the Sun going staying low." So if volcanic activity increases due to the solar minimum as has happened before you Won't change your mind! If the Sun Goes low (already) stays low (probable) then you Won't change your mind! ROARS WITH LAUGHTER!!! This thread has been dragged back to life 6 months after the last post. Interestingly though, I recently made a similar post and thought more about how to explain the fact that cooling world wouldn't necessarily disprove AGW. Let me give it in the form of a example scenario where a deep solar minimum and volcanic events suddenly appear: And as a result we get something like this (values are for example purpose only): +0.5C from co2 -0.5C from some kind of maunder minimum -0.5C from a sudden burst of multiple volcanoes Add them all up, and you get a net cooling of 0.5C. Now you see why a cooling wouldn't necessarily disprove AGW. Because that first line exlicitly states AGW has occured. The moral of the story is that simply looking at the net change of -0.5C doesn't tell you how much warming co2 caused. You need to actually split the temperature change into it's components. Letting co2, volcanic forcing and solar output all change signifcantly at the same time is like performing an experiment and letting all the variables change. It's more difficult to determine just what the co2 does if you mask it with other effects. It's far easier to rule out the contribution from co2 if only co2 significantly changes and still temperature doesn't rise. So that's why there's no reproducibility in all 23 GCM's used in IPCC AR4; they all assume different levels of "masking". Seriously, what you are essentially saying is there's no way to distinguish between natural and 'man made' warming, therefore there is no way to prove or disprove AGW. Why then do we get bombarded with catastrophic warming warnings from now until the end of this century and presumably beyond? Unfalsifiable hypotheses are great aren't they?
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Post by jimg on Apr 14, 2009 2:31:00 GMT
That's a great point socold. But how do we define "normal"?
What is the "right" temperature? Are we above it? Or below it? How will we know when or if we reach it. And do we really think that it is something that we can control?
Have we had an unusually active solar cycle over the last 100 years?
Have there been fewer eruptions?
Looking at the Vostok data, we do seem to be at a low point for atmospheric dust.
Has our firefighting policy of extinguishing forest fires, instead of allowing them to burn out put less dust and chemicals into the atmosphere?
I'm thinking that there are more than a few parameters missing from the GCM's.
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Post by poitsplace on Apr 14, 2009 4:11:52 GMT
Let me give it in the form of a example scenario where a deep solar minimum and volcanic events suddenly appear: And as a result we get something like this (values are for example purpose only): +0.5C from co2 -0.5C from some kind of maunder minimum -0.5C from a sudden burst of multiple volcanoes Add them all up, and you get a net cooling of 0.5C. Now you see why a cooling wouldn't necessarily disprove AGW. Because that first line exlicitly states AGW has occured. The moral of the story is that simply looking at the net change of -0.5C doesn't tell you how much warming co2 caused. You need to actually split the temperature change into it's components. I am constantly amazed at how absolutely TERRIBLE most people are at dealing with correlations. Even well educated people are usually suffer from the problem. So here's what you're missing. The "average" temperature is one that also involves verage volcanic activity and average solar activity. HOWEVER, until recently we've had a prolonged period of HIGH solar activity and LOW volcanic activity. There is ONLY .5C of warming TOTAL. That .5C of warming has adjustment for the LACK of volcanic activity. It has no adjustment for the (until recently) extremely high level of solar activity. Your .5C of warming CANNOT all be from CO2. In fact, we're finding more and more evidence that MOST of it can't be. Likewise, those that claim the little ice age didn't exist cannot claim that the previous warming period (which was just as pronounced) was from warming after the little ice age. OBVIOUSLY the climate has that much variation in it OR we're coming out of a little ice age. You don't get to include data only when it's convenient.
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Post by socold on Apr 16, 2009 0:58:18 GMT
This thread has been dragged back to life 6 months after the last post. Interestingly though, I recently made a similar post and thought more about how to explain the fact that cooling world wouldn't necessarily disprove AGW. Let me give it in the form of a example scenario where a deep solar minimum and volcanic events suddenly appear: And as a result we get something like this (values are for example purpose only): +0.5C from co2 -0.5C from some kind of maunder minimum -0.5C from a sudden burst of multiple volcanoes Add them all up, and you get a net cooling of 0.5C. Now you see why a cooling wouldn't necessarily disprove AGW. Because that first line exlicitly states AGW has occured. The moral of the story is that simply looking at the net change of -0.5C doesn't tell you how much warming co2 caused. You need to actually split the temperature change into it's components. Letting co2, volcanic forcing and solar output all change signifcantly at the same time is like performing an experiment and letting all the variables change. It's more difficult to determine just what the co2 does if you mask it with other effects. It's far easier to rule out the contribution from co2 if only co2 significantly changes and still temperature doesn't rise. So that's why there's no reproducibility in all 23 GCM's used in IPCC AR4; they all assume different levels of "masking". Not sure what that means, there is no masking element in the models as unlike the real world in the model world you know all the goings on in them. On the contrary I think we can distinguish between natural and manmade warming quite well. What I am saying is that this only goes for the climate we know. If a big unusual event which we have little knowledge of occurs it could throw a spanner in the works and make it harder to attribute climate change. The unfalsifiable hypotheses that all the skeptic blogs claim to have already falsified? But on a serious note care has to be taken to not to set sloppy falisification criteria for the sake of it. Simply making a cast iron statement like "if there's no warming after 20 years of co2 rise, that falsifies co2 rise having a warming effect" is wrong. The falsification has to be based on what the hypothesis actually say. It doesn't say "significant warming will happen over the next 50 years" it says "X co2 rise has a significant warming effect". Those are two different things. Yes warming will very likely happen over the next 50 years if the hypothesis is correct. But if something weird happens like a very deep solar minimum (way beyond what we are currently seeing this cycle) and the earth cools as a result, a subsequent drop in temperature might be expected even if co2 rises. In which case the falsification criteria set above would actually be bogus.
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Post by socold on Apr 16, 2009 1:05:25 GMT
Let me give it in the form of a example scenario where a deep solar minimum and volcanic events suddenly appear: And as a result we get something like this (values are for example purpose only): +0.5C from co2 -0.5C from some kind of maunder minimum -0.5C from a sudden burst of multiple volcanoes Add them all up, and you get a net cooling of 0.5C. Now you see why a cooling wouldn't necessarily disprove AGW. Because that first line exlicitly states AGW has occured. The moral of the story is that simply looking at the net change of -0.5C doesn't tell you how much warming co2 caused. You need to actually split the temperature change into it's components. I am constantly amazed at how absolutely TERRIBLE most people are at dealing with correlations. Even well educated people are usually suffer from the problem. So here's what you're missing. The "average" temperature is one that also involves verage volcanic activity and average solar activity. HOWEVER, until recently we've had a prolonged period of HIGH solar activity and LOW volcanic activity. There is ONLY .5C of warming TOTAL. That .5C of warming has adjustment for the LACK of volcanic activity. It has no adjustment for the (until recently) extremely high level of solar activity. I said the numbers are for example purpose only. As for recent warming, the warming factors must be greater than the actual observed temperature rise simply because cooling factors exist. So if you have 0.5C cooling then you would need 1C warming to get a net of +0.5C. Here's a graph just to demonstrate how it all adds up, although I am not presenting this as an example of anything real as I have no idea if the actual values are valid: www.globalwarmingart.com/images/thumb/a/a2/Climate_Change_Attribution.png/300px-Climate_Change_Attribution.pngI
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Post by LakeEffectKing on Apr 16, 2009 1:53:34 GMT
socold wrote: Tell that to Hansen:
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Post by poitsplace on Apr 16, 2009 3:46:30 GMT
LOL at the link. And if you'll consult the IPCC's own information you'll find that they state the level of knowledge of most of those things is LOW...extremely low. Even hansen implies the numbers might as well be pulled out of a hat (something along those lines) The graph also stops a bit short of 2000. From that point a LACK of volcanic activity should have increased temperatures, we went through a solar maximum, CO2 levels increased...yet temperatures have leveled off.
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