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Erm hasn't anyone notices that this is essentially the main earth temperature stabilisation loop. Clouds are pretty darn reflective, maybe up to 70 or 80 % depending on thickness but real hard data is remarkably difficult to find. When temperature rises more water evaporates which rises and forms clouds reducing the overall insolation so with less energy input temperature falls reducing the amount of water evaporated so fewer clouds form leading to more insolation so temperature rises and back round the loop. I hardly think that a few itty bitty ships will make much difference compared to the thousands of square miles of water surface.
Its pretty easy to get a respectable estimate of surface temperature variation for given cloud cover and to calculate the cloud cover / temperature relationship. A HP 67 calculator ran a sufficiently accurate model just fine when I was professionally involved with IR system performance prediction.
No Brit can doubt the reflectivity of clouds after experiencing the common grey autumn / winter / spring days when cloud cover is so heavy that ambient light is severely reduced yet things still feel quite warm. Due of course to reflected thermal radiation from the earths surface. We all know that a clear night means a cold morning 'cos more heat escapes. Except the anti CO2 greenies who really should get out more.
Spot on, Clive. I just wish people would look more at the satellite photos of Earth, which almost invariably show about a third covered with cloud. Given the piddling areas which could be affected by any conceivable number of ships the effects of even a very small natural variation in cloud cover will be dramatically evident in surface temperatures almost immediately.
Clouds represent a positive feedback because the earth doesn't cool as much, but a negative feedback because not as much sun can get through. Some nut might suggests that there is a function involved in the relationship. They might also suggest that the relationship isn't linear and might vary based on a variety of things like: axial tilt, latitude, longitude, time of day, and maybe even altitude.
Surely, Brad, but we must also remember that clouds are not just static objects in the atmosphere blocking and reflecting light but the visible manifestation of major air movements. Over at WUWT someone has been banging on for some time about the fact that, contrary to warmists' belief in a radiative forcing, much to the surface heat energy on Earth gets radiated to space from the top of the atmosphere having been convected there. There appear to be more things under heaven and earth than are dreamed of in their philosophy.
Actually positive / negative feedback is a very unhelpful way of looking at the situation. Its a classic energy balance emergent system. Overall input energy has to equal output energy and for any input energy level a simple vector can be derived to track the cloud cover variation needed to achieve this. Only needs a grey body source model at both ends. The problem is of course that locally its not a pure radiative source / sink situation so for accurate results you need to track the energy vectors of everything else that's going on. Like wind which transports energy horizontally. However in principle its possible to generate a vector array as large as you want and as accurate as you want.
Of course being an emergent system you can't calculate the thing and pin it down on a map. Only way to get the answers is to run it and see. This is a job for analogue computers, or the functional equivalent, not conventional digital machines. Computing section where I worked had a combined analogue and digital machine which was very impressive on the right jobs, easily outrunning a triplet of PDP 11(?). A modern, all digital, development would be ideal here.
Nice thing about emergent systems is that, for small changes at least, exceedingly crude models can generate a sufficiently accurate vector to track enough change for the job. My HP67 was good enough to figure out 0.1 °K target temperature changes when predicting IR imager performance! Its a trivial matter to demonstrate that the cloud feed back loop has ample stability margin to kill off any possible CO2 induced changes however calculated. An irrelevance in practice given that the CO2 band transmission length is at best, about half the height of the troposphere so CO2 changes can't have any effects anyway.
the "here" link does not work there is a v in the http.
why is bill the root of all evil? just curious why you give him so much credit?
Number Watch yeah yeah