Over at Angry Bear, there’s a good list of suggestions, generated by one of the readers, of how non-scientists can assess claims made about global warming. I agree with most of them, except for the first one:
If you can correctly guess the basic stance that some member of the discussion will take toward a new bit of news, then that person isn’t really addressing the new information. That person is merely taking the opportunity of some new event or datum to repeat a position you already know, rather than taking the event or datum as it comes and opening themselves to new implications.
There’s one problem with this and it stems from the commonly-used narrative for science stories: NEW!!!! BREAKING!!!! Unfortunately, most scientific work doesn’t result in something revolutionary that change the way people think (either on a large or small scale). In fact, if this happened regularly, that would suggest that field is very intellectually flimsy.
Some work will simply be confirmatory or replicative; that is, repeating the experiment to ensure that the result is valid. This is quite common in ex situ, laboratory experimentation, and not so common or impossible (e.g., astronomy) in other disciplines. Other new data will either expand or delimit the conditions under which the initial observation holds. Finally, some, if not most, work makes an incremental increase in some area by building on previous work.
To my mind, it’s absolutely normal to have data confirm or support a previously held position. It’s only when you exclude data that conflict with your position, that you have a problem.