"Drill, baby, drill" versus championing green energy: Donald Trump and Kamala Harris offer starkly opposing visions on climate, with the outcome of the U.S. presidential race poised to shape the planet's warming trajectory.

Neither candidate has outlined a comprehensive platform on climate, an issue that remains far from the center of the U.S. campaign, despite the country being the world's second-largest emitter of greenhouse gases, after China.

But their positions are no mystery.