I think he is wrong about what most climate skeptics are thinking.

My personal experience is that I've mostly seen two main camps of climate skepticism, both of which seem to map to contrarian sophistication levels. I don't see many people who are operating at level 2 and climate skeptics.

The first is the 'uneducated' critique, that nature is simply too big and variable for man to impact the climate, be sure he's impacting the climate, or have a desired climate reference level. This seems to mostly be out of touch with the data / scientific reasoning in general, but does fit into Adams's claim; one of the reasons why someone might disbelieve claims that we're sure about the causality and predictions is an overall poor track record of science. In this particular field, for example, some predictions of global cooling were made before, and people who value consistency more than correctness are upset by that. (It's worth pointing out that many people do give the argument "you're able to predict what the climate will look like in 80 years but you aren't able to predict what the weather will look like in 8 days?" despite the inherent difference between climate and weather, but that's mostly unrelated to Adams's point.)

The second is the 'meta-contrarian' critique, that pokes at the incentives of climate science, the difficulties of modeling, and the desirability of change. As an exercise in scientific number-crunching, climate predictions are very difficult and in a class of models where many tunable parameters can be adjusted to get highly variable results. Most of our understanding of how the climate will behave depends on the underlying feedback loops, and it seems that positive feedback loops (i.e. the temperature increases, which changes things so that temperatures continue to increase) are more publicized than negative feedback loops (i.e. the temperature increases, which changes things so that temperatures stop increasing). There's also evidence that the net effect of climate change will be positive until it's negative, suggesting that stopping change down the road would actually be better than stopping change now (if it were equally costly to stop change now and then).

(Note that both of those camps basically disagree with climatology as a field, for different reasons, and neither of them buy into the central premises of climatology but interpret the data differently.)