This is a party question, which means that there will be a good many crackpots & hired liars even among the experts, and for many, perhaps most, people the first response to any statement will not be "Is this likely to be true?" or "Is this relevant?", but "Which side is this person on?". That makes the task of a nonexpert, who must nevertheless form an opinion, difficult.

It is also clear that, politics aside, there is a lot of noise on the signal. There have been warmer & cooler days, months, years, decades, centuries, millennia, eons, and so on, and most of it has nothing to do with human enterprise or folly. In particular, only 14,000 years ago (I think it was), the ice came down to New York & St Louis, and the sea was so low that there was no English Channel and the Thames flowed into the Rhine. Since then, clearly, there has been a good deal of global warming, which has made it easier for our species to propagate. If it goes on, tho, it may well make it harder, and then it will make sense to try to do something about it, without arguing a lot about how much of it is our fault.

Very likely, we have done *something* to help it along already. No question we have put a lot of carbon dioxide into the atmosphere. Regardless of how little or how much we are contributing to current changes, it is high time we started watching what we are doing very carefully, because we are getting to be important on the surface of this planet. In that effort, neither the idolization of business nor the idolization of nature will be helpful. More actual evidence may be.

In that connection, I see some plausibility in Freeman Dyson's complaint that we are putting too much effort into necessarily crude computer modeling and too little into gathering data. Some of what we don't know yet may be good news (negative feedback loops that stabilize things), and some may be bad (positive feedback loops that may lead to runaway). Dyson says, for example, that no-one has modeled the release of methane due to the melting of permafrost, because we don't know enough about it. But if it turns out to be important, it may be catastrophic. We might have to do something about it right away -- I can't imagine what, but maybe someone can.