From the math I've seen, it's likely we're going through a warming spell. It's far less clear what's causing that. It could be "greenhouse gases," but warm and cold spells have happened before without them.
We need to keep in mind God's promise to Noah: "While the earth remains, seedtime and harvest, cold and heat, summer and winter, day and night, shall not cease" (Gen. 8:22). We'll never be able to mess up the seasons so horribly that the earth becomes unfit for us to live in, even if we try.
At the same time, we need to keep in mind God's commandments in Genesis to tend the garden and have dominion over the earth. We must pay attention, as caretakers, to how our activities affect the earth and its climate. We clearly
can have some effect, and must take pains to make that a good effect.
Why is this issue political also? Isn't it just science? Why do opinions split along party lines?
Because environmental constraints tend to have an immediate, negative effect on business, and pro-business is a right wing value. More imprtantly, we might ask why the issue tends to divide Christians from non-Christians. Perhaps because many Christians (myself included) are knee-jerk right wingers for reasons that have little to do with the environment.