I choose to be ignorant about certain things all the time - every moment of my life spent on anything except reading Wikipedia is a choice of selective ignorance.

True, but that is ignorance-of-omission. You seemed to be advocating a conscious decision to keep yourself ignorant of certain well-defined areas of knowledge. Apologies if this is not so.

How much does your life improve by having more accurate view of global warming research...?

Well, here's the hedonistic vs. goal-oriented view of rationality again. Not everything I do is directly related to satisfying immediate whims. I am a voter and also an engineer, as it happens. Both of these circumstances imply I have an ethical obligation to be at least somewhat conversant on questions of public policy & the environment.

I'd guess improvement will be tiny, and the risk of such knowledge triggering your world-saving instincts is not worth it.

If my "world-saving instincts" should be triggered, I want them triggered. Again, as a bare minimum, public policy depends on an informed public, and GW is a policy problem. But uninformed consent in a democracy is pointless, it doesn't count. We might just as well save money on ballot paper and install a grand Doge for all the functional difference it would entail.