Most climate change occurs naturally, ice ages come and go.
Human action has very little impact on climate change.
And you know this because you've studied climatology and read the best science on the issue. Or because a rightwing guy on OZ radio said so.
You don't think 6B people and 200 years of burning fossil fuels can affect the climate (and human health)? And gee, there just happen to be a number of much safer, and soon to be much cheaper, fuel options out there.
For a variety of reasons, especially situating cities on coastlines, humans can be greatly affected by even small climate change. It's mostly Big Oil, Bug Business and Greed opposing Science and Humanity. Not hard to pick a side, especially since it is the one that is almost certainly right.