Erm no, just that I always hear the "they're doing it for the grant money!" so if that's what you got from my statement, then it seems from your logic that scientist getting grant money = conclusive proof that it doesn't.
But anyways, there is lots of evidence linking the Eocene Thermal Maximum, the warmest point in time ever, with one of the highest atmospheric carbon dioxide concentrations. It was over a relatively short period of time, ~1,000 years, which lead to a mass extinction, but the problem is that at current rates human beings will reach that threshold much sooner, having obvious implications on the biosphere as well as climate, weather, etc. And whenever people bash ice core samples, they should back it up on why they're not dependable, as it is based on oxygen isotope proportions (similar to how we dependably use radiocarbon dating), and there are other techniques used. Also, there is the fact that there is an international consensus in the scientific community the global warming is real (global climate change for those of you who randomly point out how cold it is in other regions), based on collection objective data, and I hardly doubt that ALL of them are in it for the grant money.
EDIT: Also wanted to point out that 4.5 billion years is a moot point when considering how dynamic it has been over the course of the earth's age.