First off, science is *never* "settled". Some theories, having endured for decades without serious challenge, are perhaps less likely than others to be upset by new evidence to the contrary - but it is the very height of arrogance to assume that as a species we've discovered all there is to know on any given topic. That's the fundamental principal of science - that it's ALL up for grabs if you can produce replicate-able experimental data contrary to current theory...the debate is magically open again...you know, that funny thing called the "quest for knowledge".
A good second thought on science is that valid science rarely ever meshes 1:1 to pre-existing political agendas. Any time someone makes allegedly science based claims that somehow magically seem to endorse the policy objectives of one interest group or political party (say "get rid of cars, promote mass transit, get rid of modern industry" or some form of creationism) it's a hint for anyone with more than a couple of neurons to rub together that odds are getting pretty significant that some level of scientific fraud is in progress, or at least that great skepticism should be employed until all data and data collection methods are examined openly.
Spin, baby, spin!
Now, given that the prime propagators of global warming have refused to disclose their data sources repeatedly, waged a political war in the world of science against those who hold differing views, and been frantically making claims that the "science is settled on global warming" - anyone with the aforementioned two simultaneously firing neurons should have already been good and skeptical some time back. Well, unless they found it *convenient* to their political agenda...
There's a word for it....fraud....
And now the dam begins to crack, and evidence begins to pour forth of selectively choosing evidence that favors a given political/theoretical agenda, suppressing evidence to the contrary, ignoring both scientific practice and actual law by failing to release data, and apparently, in some cases, destruction of inconvenient data.
This is neither the first nor the last time that alleged scientists have failed their ethical obligations and turned out to be naught but spin doctors in drag, but it is certainly one of the most expensive and crippling such faux pas.