Climate change is happening, humans are causing it, and I think this is perhaps the most serious environmental issue facing us.

The jury is still out on whether humans are causing climate change.

This notion that manmade climate change is happening is wrong.

There is no question that climate change is happening; the only arguable point is what part humans are playing in it.

This still commits us to quite a bit of climate change, but it leaves the door open to avoiding the largest and most devastating consequences.

Climate change is the Everest of all problems, the thorniest challenge facing humankind.