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To be fair to Trevor, he did say the exact same thing. Check out his fourth paragraph. The whole discussion became bogged down with the tree issue, which seemed rather tangential to me, so I can see it'd be easy to miss, but a more careful reading would prevent these sorts of silly questions in the future.
There is no doubt that, fundamentally, the problem Dook poses -- the issue of the time lag -- requires differential equations to answer, and the exact value would depend on dCO2/dt and the complexity of your model. I don't think it would be too difficult to work out a crude approximation using something like a simple box model (which, of course, involves a system of differential equations). I'm not sure it would provide much illumination to a majority of posters here, which is why a more qualitative answer generally suffices, but I agree that it is disingenuous of Trevor to imply that the problem -- which, ultimately, he didn't really address -- can be solved without DEs.
Dook
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Given that the WV feedback is a function of temperature, they are the same question. In fact, we don't need *any* information about the feedback itself (e.g. Clausius-Clapeyron), other than the mere fact that it responds to temperature, to answer your question.
"...what will happen is not that the temperature will immmediately drop as Trevor and his spreadsheet claim.."
That's not what he said, what he said was: "the cooling effect would be immediate" which is consistent with your statement: "but rather that *the rate of increase* in the temperature will drop."
As per a dictionary definition of "cooling": 1. Become or cause to become less hot.
I.e., if you reduce CO2, a drop in the rate of increase in the temperature would be immediate. It might be small and the warming will continue for quite some time, but by definition it will be cooling and the effect will be immediate.
What you are saying is the temperature will not immediately have rate of *decrease* which is also correct.
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Edit: "What I was claiming was that if CO2 started dropping, the second derivative of temperature with respect to time would be negative..."
Again, this meets the definition of an immediate cooling effect. You might want to give a reference to exactly what Trevor said but I see nowhere where he said temperatures (first derivative) would immediately start dropping. And you appear to agree: "He of course did not use that wording"
I can't really see any point you are making here; well one that is clear anyways.
Well, part of what happens when you try to do science without knowing the math depends on the degree of precision you are 1. aiming for, and 2. claiming.
I do not know the magnitude, or the mathematics, of the albedo feedback. But I know that there is one, so I also know that efforts to paint white areas that were until recently covered by glaciers are likely to slow warming at least slightly. And thus, by a reasonable definition of the term, have a cooling effect.
And I do not need to know any of the math, really, to know that if you remove CO2 from the air, the Earth will very shortly end up cooler than it would have been if you did not remove that CO2.
I think this may be another case where you are primarily nitpicking someone's word choice. A cooling effect does not necessarily mean that temperatures will drop from what they were before... just that they will drop from what they otherwise would have been. And you agree that this is, in fact, the case.
edit:
I would like to note that "it will cause a cooling effect" is *not* the same as "it will cause cooling". And I think most people even tangentially related to the relevant sciences will understand the difference.
Trevor is right, you are wrong. The reason you are wrong is that you are using the analogy that CO2 is a thermostat and there is some sort of thermal lag in climate like there would be in a house. However, you are mistaken in that assumption. In fact, a thermostat controls the energy input to the house (the furnace). Shut off the furnace (i.e., the energy input into the house) and the house starts to cool immediately. In climate, CO2 is the furnace. Reduce CO2, and the cooling begins immediately. The thermostats in climate are the feedbacks and heat sinks like the ocean and cryosphere. But regardless of how big those are, if you shut off the furnace, the house cools.
Now, go apologize to Trevor. There's a luv.
So what you’re saying is that when I state “at this stage the effect would be to slow down the rate of warming” it’s wrong, but when you state “The temperature will rise for a while, but it would not rise as fast as it otherwise would have” it’s right. Explain. PS – “I’m always right and everyone else is always wrong” is not an acceptable answer.
I have stated again and again that a reduction in greenhouse gases would NOT cause an immediate drop in temperatures, I stated the other day that it would take about 84 years before the warming stopped from the point of zero further emissions. You well know this as you whinged about that answer as well, so now you’re just completely contradicting yourself.
Before jumping on your high horse and making false accusations it would help if you actually read what was on the screen in front of you – and understood it. All you’ve done of late, repeatedly, is to fail to grasp what other people are saying, apply your own erroneous interpretation and then, quite foolishly, accuse them of being the ones making the mistakes.
Hey Dook has provided much of the necessary information in his hypothetical scenario, you’ll need to add some of your own values – so go ahead and do the calculations yourself and answer Hey Dook’s question.
I asked the question to which you refer http://answers.yahoo.com/question/index;...
so I'd be interested to see your answer there, preferably spelled-checked, and including any relevant differential equations (using any readable and unambiguous notation). I didn't ask about temperature lags, only about water vapor feedback lags, so your answer should preferably focus on the latter. Most of what Trevor talks about there is a tangent concerning a conceivable, though very speculative, mechanism for a rapid reversal of the upward trend of CO2 concentration.
The math is not always important, many times in my work in power stations, I would come up with ideas to improve efficiency or performance, and because my math is not good I would take my idea to the relevant dept and have them help work the math for me.
You can be the best mathematician in the world but if you have no ideas what the worth.
What happens when someone tries to turn an extremely complex system into a simple math problem? Confusion, exaggeration, alarmism.
Darwin seems to have managed pretty well.
A poster asked about the effects of renmoving CO2 from the atmosphere.
Another poster who thinks he can understand dynamical systems with very limited math wrote back
"There would be no noticeable lag between CO2 reduction and H2O feedback kicking in and the cooling effect would be immediate... PS – No differential equations were used in the making of this answer (just a very simple 9 cell spreadsheet)."
He did not use differential equations but answer is clearly wrong though!
The Earth is in a disequilibrium state now. If CO2 remaimed constant, the Earth would heat up for many years to come. One can think of it as if the temperature has not yet caught up to the CO2 level. It is as if I keep raising the thermostat setting for a room, and then stop raising it. If the temperature of the room has not yet reached the thermostat level, the temperature will keep rising for awhile even if I do not rause the thermostat setting further.
So if we start decreasing the CO2 levels, what will happen is not that the temperature will immmediately drop as Trevor and his spreadsheet claim, but rather that *the rate of increase* in the temperature will drop. The temperature will rise for a while, but it would not rise as fast as it otherwise would have.
No doubt, most of you here have no idea about how what I just explained relates to differential equations.
try reading books of maths published by MIR it would be of great help
