Without direct evidence, and with poor model predictability, what other avenues are available to us? This is where things get messy because we are humans, and humans tend to select those avenues that confirm their biases. (It seems to me that the less direct evidence there is for a position, the more passion is applied and the more certainty is claimed.)
One avenue many folks tend to latch onto is the self-selected “authority.” Once selected, this “authority” does the thinking for them, not realizing that this “authority” doesn’t have any more direct evidence than they do. Other avenues follow a different path: Without direct evidence, folks start with their core beliefs (be they political, social or religious) and then extrapolate an answer to climate change from there. That’s scary. It’s not hard to imagine that we argue about these ways of thinking.
Then, there is that time-honored, media-approved, headline-grabbing source of truth _ the opinion poll. The poll can be of scientists, non-scientists, man-on-the-street, anyone with a smartphone, groundhogs whomever. Think about this. If no one (not even an esteemed scientific organization) has direct evidence to substantiate any claim of the impact of greenhouse gases on climate, what will an opinion poll provide besides entertainment or (worse) justification for one’s agenda?
If you give this polling tack some thought, it’s relatively clever. Without direct evidence to prove or refute the claims of a climate poll, the poll becomes the popular avenue for supporting whatever claims are being made. With enough attention, a poll’s climate-claim morphs into “settled science.” (Scientifically, that’s pathetic.) So, we argue even more.
Finally, and ironically, what to do about climate change is not a scientific question — it is a moral question. The question is this: “Is there value in enhancing the quality and length of human life?”