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A £65bn question. |
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#101 |
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Join Date: Aug 2016
Posts: 349
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Your inane posts, currently...
Oh, right. So you are indeed the type of science denier who simultaneously asserts the over-riding importance of water vapour as a greenhouse gas, whilst apparently being blissfully unaware that the amount of it in the atmosphere is a function of a) availability, b) temperature, and c) the physics of the Clausius-Clapeyron relation. Yes, you say all sorts of things that aren't true. Because it's the latest thing for science deniers to cling to in their attempts to undermine the need to reduce CO2 emissions, presumably. |
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#102 |
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Join Date: Dec 2004
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So do you think, to quote, " the Earth has net positive feedback's to an increase in radiative forcing."?
But I hope you don't think that the existence of positive feedbacks in the climate system means that there is no mechanism that limits the magnitude of the temperature excursion (in either direction) to be expected from any such change. Because that's where I suspect you are trying to take us. |
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#103 |
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Join Date: Aug 2016
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Yes. And to a decrease in radiative forcing, obviously.
But I hope you don't think that the existence of positive feedbacks in the climate system means that there is no mechanism that limits the magnitude of the temperature excursion (in either direction) to be expected from any such change. Because that's where I suspect you are trying to take us. But back to your reply, what are these limiting mechanisms? |
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#104 |
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Join Date: Dec 2005
Location: In a jar, on a shelf
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For example you claim climate models are accurate but have yet to provide any evidence that they are.
Problem with that is they still don't match observations for aerosols or black carbon (aka soot). Then again, the introduction of clean air acts around the world and shift from domestic coal burning may also explain temperature rises, especially in urban areas. |
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#105 |
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Dear, dear, you are a suspicious person. I wasn't trying to take us anywhere, I was simply trying to clarify your position since you appear to have a habit telling people they are wrong without providing any explanation as to why.
Positive feedbacks in the climate system are often objected to by people claiming to have an engineering background. They think that they imply an unstable system. So your question was something of a red flag. Quote:
For example you claim climate models are accurate but have yet to provide any evidence that they are.
For some values of "accurate". My objection was to your implied claim that they were badly flawed, rather than merely imperfect, with deficiencies acknowledged by mainstream science.I rather lost interest when your claim turned out to be based on some things you had read in the media, but weren't sure what, or where. I am often prepared to do more work in refuting an argument than the person put into making it, but not always. If you are genuinely interested, you could start by looking at how climate models are evaluated in the IPCC assessments, or at a number of papers published since. Quote:
But back to your reply, what are these limiting mechanisms?
The over-arching negative feedback is of course the Planck response, whereby the thermal radiation from a body (in this case, the Earth) increases in proportion to the fourth power of its temperature. But there are other limiting mechanisms. Clearly the ice-albedo feedback (for example) is limited by the presence of ice. Once it's all gone, further warming won't make it any worse! |
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#106 |
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The over-arching negative feedback is of course the Planck response, whereby the thermal radiation from a body (in this case, the Earth) increases in proportion to the fourth power of its temperature.
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#107 |
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Glad you mentioned that one. So how does that fit with, say, andykn's suggestion that 0-275ppmv CO2 lead to 30C warming?
Is this your enduring problem with logarithms again, or something else? |
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#108 |
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Join Date: Aug 2016
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I apologise for that, but what you have to understand is that most of the people I argue with on here about climate science are people I have argued with many times before. So they have been told repeatedly what mainstream science says, but they refuse to learn anything, and will usually just rehash the same incorrect arguments over and over again. Providing detailed responses to their vague and incorrect assertions each time they make them is something of an exercise in futility.
Positive feedbacks in the climate system are often objected to by people claiming to have an engineering background. They think that they imply an unstable system. So your question was something of a red flag. For some values of "accurate". My objection was to your implied claim that they were badly flawed, rather than merely imperfect, with deficiencies acknowledged by mainstream science. I rather lost interest when your claim turned out to be based on some things you had read in the media, but weren't sure what, or where. I am often prepared to do more work in refuting an argument than the person put into making it, but not always. If you are genuinely interested, you could start by looking at how climate models are evaluated in the IPCC assessments, or at a number of papers published since. The over-arching negative feedback is of course the Planck response, whereby the thermal radiation from a body (in this case, the Earth) increases in proportion to the fourth power of its temperature. But there are other limiting mechanisms. Clearly the ice-albedo feedback (for example) is limited by the presence of ice. Once it's all gone, further warming won't make it any worse! BiB An overall positive feedback would imply an unstable system but thanks to the Planck response that isn't what we have got. So it comes dow to the relative magnitudes of the feedbacks (positive and negative) within the system. |
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#109 |
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BiB
An overall positive feedback would imply an unstable system but thanks to the Planck response that isn't what we have got. So it comes dow to the relative magnitudes of the feedbacks (positive and negative) within the system. |
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#110 |
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Inactive Member
Join Date: May 2011
Posts: 18,881
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They can be, sort of. So there are model reanalysis projects that compare climate models to the real-world, and training where they can be fed data to try and train them. So rather than forecast, they hindcast and results compared to observations. Problem with that is they often only hindcast accurately if they're tweaked to use more aerosols or black carbon.. Which basically helps with the lack of warming in observations.
Problem with that is they still don't match observations for aerosols or black carbon (aka soot). Then again, the introduction of clean air acts around the world and shift from domestic coal burning may also explain temperature rises, especially in urban areas.
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#111 |
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The question is, when they find, in hindsight, that the original model gave the wrong results, do they headline publish it, sneak a little note in somewhere or let it fade into obscurity? I need the answer for my new project. shhhhhhh
![]() You seem even more than usually perplexed. |
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#112 |
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Join Date: May 2011
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You do know that there isn't just one climate model, don't you?
You seem even more than usually perplexed. |
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#113 |
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Of course I know there's more than one. I'm asking in respect of any or all of them.
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#114 |
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You do know that there isn't just one climate model, don't you?
And any idea if any managed to predict the sudden fall in temperatures? |
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#115 |
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I suppose we'll have to agree to differ.
I see some of yourr points but I think iit's a little early to write off a whole technology. The 'renewables' response would be to fit a steam engine or perhaps paddle wheels to your ship, then compress air and store it. When the wind's not blowing, release the air into the sails and off you go again. Or you could just give in to progress and efficiency, and trade your clipper for a steam ship. They did manage to last quite a while, but we're building ever better steam ships today, ie most Navy ships. |
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#116 |
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Inactive Member
Join Date: May 2011
Posts: 18,881
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Perhaps if you named one of them, we could look at its history for you.
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#117 |
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Therein lies the problem. If climate scientists understood the climate, why then is there more than one model?
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And any idea if any managed to predict the sudden fall in temperatures?
Climate models don't usually address annual variations, oddly enough.Presumably you are referring to the latest claim by the usual assortment of idiots - such as the serial liar and worthless Daily Mail hack David Rose - that because temperatures fall immediately following an El Nino peak, that means global warming has ended, just as they previously claimed about 1998? When can we expect the "There has been no warming since 2016" bleating to start? |
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#118 |
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Join Date: Dec 2004
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You're hedging.
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#119 |
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Join Date: May 2011
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You don't actually know the names of any climate models, do you? But you know you don't like them.
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