This argument really isn't going to go anywhere. Both sides, especially the anti-human contribution side (in this case specifically, not in general) like to say that their interpreted data are "facts." Problem with that is, as we all know their is more than one way to read data. The exact same data can be used just as convincingly to support an infinite number of hypotheses. Another problem with this argument is that it does not take into account the accuracy of the various scientific methods used to gather and assess the data. Clive's original post supports this. Simply saying my "facts" say you or your data are wrong is not a meaningful discussion into this. Philosophically this is a major problem with science because it is based on induction which, in terms of proving something, has some serious flaws. Induction also fails when data that is contrary to the conclusion is excluded. Again, this happens on both sides of the coin and is not targeted at any group specifically. So if arguing which view is absolutely right is really impossible, especially for people like us who are merely reading other people's publish work, what should we do about this issue. We live in a democratic society, I assume most people like that idea, and we believe in the democratic ideals. Therefore, does it not make sense that if the scientific community is overwhelming one-sided on an issue that we should trust in "the experts?" It is also important to remember that the burden of proof will always be placed on the person trying to swim upstream, but that those bold and risky predictions, while not proof or support in themselves, are really what forging human understanding is all about.
There are several famous instances of a challenge to the status quo that have ultimately become accepted. For instance, the earth is round and not the center of the universe. One could argue that this means we shouldn't accept the dominant scientific opinion because it can be wrong. Which is true, but all that argument really accomplishes is stating that all science can be wrong. Which also is true. But over time, and study, and the interpretation of data and with the injection of new ideas our knowledge grows. And maybe, just maybe, we get one step closer to "the facts."