[math-fun] Elementary climate change explanations?
E Salamin: CO2 has a very strong absorption band around 15 μm from the bending mode. CO2 and H2O have complementary absorption bands, so their effects are additive.
--ok, good. And here's somebody trying to make pictures: http://clivebest.com/blog/wp-content/uploads/2010/01/595px-atmospheric_trans... http://noconsensus.files.wordpress.com/2010/04/image71.gif
There's no H2O left in the atmosphere of Venus. UV radiation breaks up the H2O, the hydrogen is lost into space, and the oxygen is too reactive to remain.
--right again. Venus 95% CO2, H2O is only 20 ppm. But whatever. Point is, there is big greenhouse effect on Venus.
Nuclear
--I think Nuclear and breeder rectors have to become very important. It will happen. The problem is, when it does, there will be many years less research that there should have been.
Carbon taxes without nuclear is pretty useless.
--if carbon taxes, then nuclear more attractive, hence will happen more. (Duh.) Also, other things less attractive, like long automobile commutes, uninsulated houses.
Taxes won't reduce CO2 emissions, just raise the cost of energy.
--cross country comparisons refute you.
Gosper: Greenhouses work just as well sheathed in material 100% transparent to IR. They work because they are made of AIR! http://www2.gi.alaska.edu/ScienceForum/ASF8/817.html
--interesting. Probably even true, now I think about it. The major heat loss mechanism is probably convection not IR radiation hence the sheeting cuts off the convection, and voila. Anyway, the larger point is: insulation. Sunlight comes in, but heat has more trouble getting out, so hotter inside. Whether the insulation works by cutting off convection, conduction, or radiation, still get the same heating effect. In the case of greenhouses with glass, all 3 are cut off, especially with 2-pane thermal glass insulated black-interior "hot boxes," which can really get hot inside.
http://eesc.columbia.edu/courses/ees/slides/climate/absorption.gif is probably a better picture,
This can't be right. The outbound, reradiated IR heats the plastic? No matter how thin? Bounces off? (There are hundreds of ridiculous diagrams in Google images depicting this.)
--actually, if IR radiating from earth surface hits an absorbent material (CO2, or plastic, or glass) then that material will then re-radiate that IR in both up & down directions. If up, then another absorb and re-radiate event likely. If down, the earth re-absorbs the heat. The net effect is not that the earth is entirely prevented from losing heat, it is merely a slowdown in the rate of heat-loss for a given earth-temperature. I.e. "insulation." The CO2 effect is as though the earth had reduced black body emissivity but same black body absorptivity. Mildly related: It is estimated that heat produced in sun core takes 200K years to escape, http://articles.adsabs.harvard.edu/full/1992ApJ...401..759M/0000760.000.html since the sun's gas is a thick layer of insulation that slows down radiative transfer.
WDS: Nuclear
--WDS: I think Nuclear and breeder rectors have to become very important. It will happen. The problem is, when it does, there will be many years less research that there should have been.
ES: I posted a comment about breeder reactors on this web site from Art Robinson's unsuccessful run for Congress. http://www.artforcongress.com/issues/energy-independence
ES: Carbon taxes without nuclear is pretty useless.
--WDS: if carbon taxes, then nuclear more attractive, hence will happen more. (Duh.) Also, other things less attractive, like long automobile commutes, uninsulated houses.
ES: That's true only if nuclear is permitted to compete. The liberals want your carbon tax money, but won't let you choose nuclear in return.
ES: Taxes won't reduce CO2 emissions, just raise the cost of energy.
--WDS: cross country comparisons refute you.
ES: Citation please.
participants (2)
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Eugene Salamin -
Warren D Smith