"Dan" wrote:

I do dismiss denial of reality: creationism, for example.

Anyone who has access to modern knowledge and still believes Earth's life
forms were poofed into existence just can't -or won't- think straight.
Sorry if that's offensive, but that's a fact.

You're so steeped in your own philosophical miasma that you don't
realize how ridiculous your last statement is.

There is not a single "fact" established regarding origins. Science
cannot, will not, and has not done more than speculate.

Utter nonsense. The only thing we haven't got a handle on is how the first
proto-life appeared on the planet (Creationists are the ones who claim to
know). Everything since is pretty well figured out. It's a fact that all
the species that exist today evolved, not poofed.

Do go on about first causes. I'd be ecstatic to learn what the "facts"
are.

Oh -- and have we lost our reference for the "isotopic smoking gun"?

Nope. There are plenty, but here's one:

http://www.radix.net/~bobg/faqs/scq.CO2rise.html


CO2 produced from burning fossil fuels or burning forests has quite a
different isotopic composition from CO2 in the atmosphere. This is because
plants have a preference for the lighter isotopes (12C vs. 13C); thus they
have lower 13C/12C ratios. Since fossil fuels are ultimately derived from
ancient plants, plants and fossil fuels all have roughly the same 13C/12C
ratio - about 2% lower than that of the atmosphere. As CO2 from these
materials is released into, and mixes with, the atmosphere, the average
13C/12C ratio of the atmosphere decreases.

It is a simple matter to compare the isotopic ratio in the current
atmosphere to that in samples from ice cores.

Guess what that comparison reveals?