RoyG wrote:As far as your second statement is concerned, a better term would be buffoonery.
But only in a purely semitic light. I don't think you meant it in the way you said it.
I can claim that martians exist, but w/o any sort of scientific literature to back up my claim it doesn't really do anything for anyone.
It's called "having an opinion." An opinion doesn't have to be proved to anybody, and so long as you don't go imposing it on others, it's neither buffoonery, nor (even if it's contradictory) ambiguous. Even the Mahatmas who've seen God - Adi Shankara or Ramakrishna - don't go proving it to everybody, they only train the ones who specifically come to them as disciples. Not that I'm making any claims to Mahatmahood.
I meant in terms of solar radiation absorption. The ice sits on ground in instead of floating on water which acts a heating reservoir. So you won't see as great a temperature fluctuation.
This is the ambiguity I'm complaining about, saar. First you say "southern latitudes receive less solar radiation," then you amend it to "I mean - how much they absorb."
But what you're saying is a plausible explanation, that the sub-layer (water or ground) does make a difference - not to the heat absorbed, because that comes directly from the sun (or greenhouse heating) and only has to do with the absorption characteristics of the ice itself, but in terms of temperature change, which depends on how much heat can be transferred to the sub-layer. If, further, the ice layer in the northern hemisphere is thinner than the one in the southern, then that makes the figure you referenced even more likely. In addition to the effect you mentioned (which I'm inclined to believe will be rather minor), there is the bigger effect of "latent heat of melting," which would lead to the same result (if the ice layer thicknesses were different).
This can happen regardless of whether the forcing function (the source of the heat) is due to greenhouse heating, direct changes in the sun's output itself, or some other heating function. In any of these cases, varying thickness of the ice layer between northern and southern hemisphere can lead to a temperature anomaly distribution, just like that referenced figure. So what is it about that figure which specifically leads to the conclusion that it is greenhouse heating which is causing that anomaly pattern? My opinion is - nothing. And this opinion isn't just an opinion (this time), but based on what I've learned of the principles of heat transfer. You are free to verify this with other folks who have knowledge of heat transfer, and they'll confirm this (or not - see, scientific consensus is not a given, even among two experts in the same field).
The figure above is a little demonstration of what I mean. You heat a pot of water, steam comes out. Is it because of the direct addition of heat, or is it because of the emissions of CO2 and methane (yes, burning wood will release some methane), which reach the atmosphere, cause greenhouse heating, which in turn causes the water to boil? OK, this is a ridiculous example.
In the second panel, we again have two cases. In the first case, we have hundreds of millions or even billions of distributed heat sources - cars and planes and trains, factories and power plants, electronics which generate heat, light bulbs, fans, motors, compressors... all of which generate heat. These heat sources have come into existence after the industrial age began. Well, that's an explanation of the heat dumped into the atmosphere right there. Why go to this convoluted "greenhouse gas model," (second case in second panel) and hold CO2 entirely responsible for the heating?
In both cases in the second panel:
* The warming is caused by humans, and started after the industrial age began.
* Since the heat will spread to affect the entire globe, regardless of whether it is due to distributed heat sources or greenhouse heating, we will see some areas of cooling, some areas of heating, but the overall trend will be heating. *This is no longer that UHI effect we are talking about - proximity of temperature sensors to urban centers.*
* Rural or urban areas, it doesn't matter - they'll both be affected. Convective, conductive, advective (wind), and radiative transfer will transport that heat to all areas of the globe.
* If the northern hemisphere ice has a different sub-layer than the southern hemisphere ice, and if the thicknesses of the layers are different in both hemispheres, we could very well see the temperature anomaly pattern from your referenced figure. Because when the northern hemisphere ice melts (earlier than the ice in the S. hemisphere), it could lead to the runaway effect you mentioned - more solar radiation is absorbed. Also the much more significant latent heat effect. So there can now be two forcing functions - distributed heat sources, and direct solar radiation.
So, by the principle of Occam's Razor, which explanation will you pick?
What is different between the two cases?
* In the first case, sequestering the emissions (or CO2 in particular) will achieve nothing, as far as curbing the warming trend goes.
Do you see where I'm going? Even if it is a given that human activity is causing warming, there is a much more direct explanation for this warming, which also explains the observed facts. The solution would be to push for renewable energy, reduce wasteful consumption, etc. - that would also control the amount of emissions.
Now I'll give you one more reason to pick the first explanation (heating from billions of distributed sources) over the second (greenhouse heating). Remember that hubbub, years ago, about how the ancient temperature and CO2 level record showed that CO2 level increase *lagged the temperature increase by 800 years or so?*
The link between temperature rise and CO2 level is iffy. There is a better and more direct explanation for this temperature rise, *even if it is human-activity-induced.* And there is still the competing explanation of "increased solar output." If this heating is human-induced, then I agree, it is a good idea for humans to do something about controlling it. Only, curbing CO2 might not be that something.