Way Off-Topic: slowwhizz & CO2 @slowwhizz wrote: If CO2 in the atmosphere causes the earth to get warmer by reflecting normal radiation cooling at night (thereby trapping heat), why doesn't CO2 reflect radiation heat from the sun during the day (like a cloud of water vapor or dust from a storm) to make the earth cooler than normal?
First, CO2 in the atmosphere does not reflect radiation. Obeying various laws of physics, the CO2 molecule can absorb very narrow bands of energy within the electromagnetic (EM) spectrum, then quickly re-radiate that same energy. The direction of the re-radiated energy is random, so sometimes the radiation continues in the same general direction of the original, sometimes is re-radiated in the general direction from where it came. The net result of this process is to cut down on the rate of energy loss into space.
Most of the energy in sunlight comes to us within the visible region of the EM spectrum, but CO2 has no absorption bands within the visible spectrum, so it has virtually no effect on sunlight. At night, the earth radiates energy, predominantly in the infrared region of the EM spectrum, and CO2 has several narrow absorption bands within the infrared region. That is why CO2 has an impact on the energy loss from the earth, but not the incoming energy from the sun.
The common analogy used is the "greenhouse effect". In a greenhouse, the sunlight passes through glass, or transparent plastic, relatively unattenuated. The sunlight is absorbed by the objects inside the greenhouse, which radiates infrared radiation. The glass or plastic that readily passes sunlight, absorbs much of the infrared radiation, then re-radiates some of it back into the greenhouse, and some of it to the outside. The actual physics in this analogy is different, but the net result is similar.
The above is greatly simplified, but I have worked with energy transmission through CO2 starting in the early 1970's. The work was on military applications, but the physics is the same. I will not engage in a discussion of global warming, climate change, or any such sort. I do suspect the many "scientists" in the argument, on both sides of the debate, don't understand the physics behind their computer models. Also, their conclusions has more to do with money, politics, and personal beliefs than it does with science... IMO. 'Nuff said. Trin