Ah, yes, another "why is everyone so gosh darn partisan" argument.
There are a wide range of issues on which people simply do not reach a consensus. Most of the time, people come to one of two (rather than 3 or 4 or a million) general opinions on said issue. Like global warming: you either think it is probably happening and something should be done about it, or you think it isn't and that nothing needs to be done.
People who fall onto one particular side of an issue tend to fall onto the "same" side of other issues, as well: that is, the side that other people on their side of the first given issue also fall. This isn't due to brainwashing by "the media" or other purveyors of "partisanship." This is just the way that people's opinions naturally shake out on the major issues facing our society today.
In addition to lamenting "partisanship" in your post, you also appear angry that issues like global warming have become "political." First of all, every important issue becomes "political": people disagree on the best policies for addressing an issue. Thus, it becomes political.
And yes, each person's general worldview and economic interests inform their analysis of objective scientific data. If you have a financial and personal stake in an economic enterprise that produces greenhouse gases, you of course are going to view the data on global warming differently than a person who does not.
This scientific issue may be divided "along party lines," but the problem isn't with the party system or "partisanship." But of course you're right that some people seem to be ignoring overwhelming scientific data. And I think we're getting pretty close to a consensus that global warming does, in fact, exist. Good luck finding a politically workable approach to mitigating it, though.