Canuck wrote
I don't think that's a valid analogy. We can quantify the increased risk of cancer due to smoking, or exposure to other carcinogens. We can quantify the lowered risk of cancer due to a balanced diet. These risk factors have been quantified through studies on millions and millions of individual cases. Global warming on the other hand, doesn't have the same luxury. There's only 1 case to test hypothesis's on. There's a huge difference in certainty between the two.

I think it is a valid analogy. I am old enough to remember that people were once sceptical of smoking as a cause for cancer. A female smoker friend of mine was reassured by her doctor that women did not get lung cancer, and they didn't (in any number) then because women did not smoke as much as men until the 50s. However this ignorance did not mean that no-one was treated to relieve the symptoms of cancer. Similarly when AIDS first started people were not refused treatment because the disease was strange and new, and the symptoms did not conform to any known prognosis. The symptoms were treated. The cause was not known for years after the first outbreak, but treatment was not refused because the reason was not known.

I cannot see how we in western style countries can morally stop development in Third World countries. We enjoy a standard of living that ensures we have safe water, healthy food, education and medical care. How can we deny this to others? I don't know the answer and I doubt anyone does. But I don't think that holding off from trying to mitigate the effects because we are squabbling about the causes is going to get much achieved either.