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Look, here's the thing. We know that CO2 absorbs light energy in the frequencies reflected by the Earth more than the frequencies that arrive from the sun. That is, any CO2 that you have in your atmosphere is going to lead to an increase in the rate of absorbtion of energy from the sun on a planetary scale. The spectrum of Earth's reflected light has been confirmed by satellites, the absorbtion spectrum of CO2 has been determined in lab experiments. That means that the null hypothesis for an increase in CO2 in the atmosphere will lead to an increase in the temperature of the Earth. The increase of CO2 in the atmosphere is also something that is directly measurable, and indeed, if you just take the scientific records from the last 50 years, you see a large increase of CO2 in the atmosphere. We can reasonably speculate that this is due to the massive increase of burning of fossil fuels, as we know that burning fossil fuels releases CO2, and we know that we have massively increased the quantity of fossil fuels burned. That is the basic case for AGW. Afterwards, we can start to look a feedback loops, changes in albedo, effects at high altitude etc, but the basis for AGW is what I just laid out, and is confirmed by measurement. If you want to knock of AGW as a scientific hypothesis, you have to propose an alternative model that describes the same data, along with an experiment that can be conducted that will enable us to identify if your theory or AGW is correct. No-one, and I do mean no-one, has been able to meet that simple challenge. AGW is quite simply the best explanation that we have that fits the data. Come up with a better alternative, get meteorologists to agree that it's valid, and then I'll listen to what climate change deniers have to say. Until then, they've got nothing and as far as I am concerned are dangerously delaying changes to our behaviour that are urgently needed to avert a serious threat to the very survival of the human race. That is all. |