Humanity has never removed an atmospheric pollutant at a global, continental or, even, regional scale — we have only ever shut down the source and let nature do the clearing up. The scale of the challenge is immense. We must slow the carbon clock to a crawl before we can turn it back.

[…] Recording TV programs, and then skipping through commercials during playback, I don’t often watch live television. Today, a 30-second…