You're confusing the carbon that's already in the carbon cycle and the carbon that humans are adding to the carbon cycle by digging up coal and drilling oil and burning them. Humans are responsible for nearly all of the excess carbon dioxide added to the atmosphere in the past 200 years. We don't want to stop the carbon cycle -- that would destroy life as we know it. We just need to slow the pace at which we add carbon to the carbon cycle so the system can have time to absorb and deal with the excess. We're not only causing warming, but also acidifying the oceans.

I explain this below and another poster says the same thing. What Hansen actually said and what you're claiming he said are two completely different things. He is referring to a possibility, and you're acting like he's saying it's a certainty.

If you look carefully, there is an IF in the sentence. IF we burn all fossil fuel [it would lead to] a runaway greenhouse effect that would destroy all life on the planet, perhaps permanently" Similarly, IF I put a loaded gun to my head and pull the trigger I will die. That doesn't mean I'm saying it will happen. It would be quite difficult to burn ALL the fossil fuel, and I don't think we'd keep doing it after the effects became undeniable to the most ardent "skeptic".

I haven't heard of any solid data suggesting what the actual cost and benefits are, beyond the "sky is falling" arguments

I don't think you've been listening hard if you haven't heard of the Sterm Review. It's 700 pages long and doesn't refer to the sky falling at all. I keep seeing references to "sky is falling" arguments, but I haven't heard of any. Could you point me to one?

That absolutely is a classic denier position, because it sounds sensible on the surface (just give me some more proof), but in practice the goalposts move, so that there is never enough proof. The whole argument is set up that way -- science can never "prove it irrefutably" because that wouldn't be science.

But we've been burning fossil fuels on a massive scale for less than 200 years. Why not look at about 200 years of data to see if doing so caused warming? The consensus is that it has. If you disagree, I'd like to see some evidence.

Let's start with Arrhenius over 100 years ago. The falsifiable claim is that burning fossil fuels will raise the concentration of carbon dioxide in the atmosphere and cause warming. We have observed the warming. Had we not, it would have falsified the hypothesis. Surely you've been following this over the years and this is all old news.

Right, you can never validate a hypothesis in science. You can only fail to falsify it. In other words, no one can seem to come up with another good explanation for the warming we've observed, so we've failed to falsify the idea that it's due to carbon dioxide emissions, a hypothesis first proposed in 1896. That doesn't mean it's the truth, but I sure know which way I'd bet!

I suppose you could say that about anything that happened over 120 years ago.

I'm not confusing patents and copyrights. A computer can process computer code, literature, or a photograph. They are all copyrightable, not patentable. Interestingly enough, a computer can also process a patent, which certainly is patentable. The idea that anything a computer can process is not patentable is obviously absurd.

So the human brain is not a computer?

Code is not patentable. Algorithms are patentable.

A computer can interpret Shakespeare, so therefore literature is math. No, I don't think that's a sound argument.

Prove that physical reality is not math. Start by showing that it is not represented by 1s and 0s at the lowest level.

Any physical machine can be simulated on a computer, which includes a Turing machine. That doesn't mean the idea is math. In other words, the fact that X can be implemented on a computer does not imply that X is mathematics.