[demallien]

Not once have I seen a global warming proponent who was willing to debate it on a scientific basis,

Science is not done by debate. The issues are too complex to be conveyable in the cut and thrust of a discussion. There is a reason that the gold standard of scientific research is the peer review journal and not debates.

Until you understand this point, you aren't able to understand how wrong you are on this subject. The reason no one knowledgeable will engage in a debate is that they know how long it will take to explain to you all of the experiments that have been done that lead them to the conclusion that human-caused global warming is real. By explaining the experiments, I mean explaining in detail the methodology, the results, and the mathematical analysis. It is literally years of work. But here's the thing. Scientists themselves have done that work. Each experiments methodology and analysis is reviewed thoroughly by knowledgeable people before the result is accepted by the community.

Once you have educated yourself on this huge body of work, you too will understand the futility of engaging in a "debate" with someone too ignorant to know what they don't know. You will also understand just how strong the evidence for GW is.

[loewenskind]

>You will also understand just how strong the evidence for GW is.

Here by GW I presume you mean Man made GW. In that case, many of the proponents are also ignorant of how strong (or not) the evidence is. They simply assume that the people paid to know, do. That's not a valid assumption.

[demallien]

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.

[alextgordon]

I just want to say: Thank you. This is the first time someone has actually explained the science without bullshit or a large number of holes ("oh look here's a graph with CO2, and here's a graph with temperature, they seem to be doing the same thing - that explains everything").

[jberryman]

It's odd to me that you wouldn't have browsed wikipedia or come across a better explanation of global warming than "here are some graphs"

[narag]

I have read a lot about this question and never found such a short and to the point explanation as demallien's.

[astrange]

Did you look, or are you just complaining that you haven't randomly absorbed the right kind of explanation?

http://climate.nasa.gov/

Although that site doesn't really work without Flash.

[loewenskind]

Another poster in this thread claimed that we've had higher amounts of CO2 in the atmosphere in the past without runaway global warming. Is he simply incorrect on this point? Has the point been addressed/disproven anywhere?

And my point with the post you responded to was simply to point out that there is a lot of claims being made by people ignorant on the subject from both sides.