Alrightey, everybody, pay attention. Gonna show ya how it's done. Azzaman has proposed a theory: that we humans could have set off one of those great big CO2 spikes I previously mentioned. Now, I'm not going to ask Azzaman to substantiate his claim; no evidence is required at this stage because it's not a definite claim. It's a "maybe" claim which is equivalent to a question. Did human beings trigger a great big CO2 spike? No evidence or further substantiation is required to ask a question, and he asked a good one. Just because the last five were natural doesn't mean the same phenomenon can't get set off artificially. It's when someone tries to answer "yes, that's happening" or "no, it's NOT happening" that the circumstances change. When you move from maybe to a definite yes or no, now you're making a claim of fact. Such claims must be substantiated by evidence, experiment, or preferably both. I've seen no evidence to either substantiate or disprove Azzaman's claim--mostly because I haven't looked yet. However, just because he hasn't posted evidence to prove "yes" does not mean the answer is "no". It means the answer is "unknown". Is the Earth's magnetic field contributing to global warming? I never said "definitely yes" or "definitely no". I said I wasn't sure. Therefore no further evidence is required on my part; all I did was ask a question. If you say the answer is "definitely no" you must substantiate it. Nobody has. Is the Earth having a natural CO2 spike? Same deal. More than one poster in here says "definitely not". But they have posted no evidence. The claim has been made that the current spike is inconsistent with previous ones--but no evidence has been posted to support that. Those who wish to "definitely" disprove the above two theories must back up their claims. They have not. However, failure to back up a claim does NOT allow BasketCase to relegate it to the trash bin. If Sidhe cannot prove the answer is "no", that does not make the answer "yes". It makes the answer "maybe". That is real science.