J asked me this week what would happen if humans disappeared from the earth overnight. I remembered the 2008 documentary series “Life After People.” It is a speculative exploration of what may happen on earth after humanity’s sudden disappearance. Although I watched it dubbed in Spanish when my command of the language was still poor, I reiterated the main points to my son. Firstly, animals that depend on humans would die off or evolve. Nature would quickly overtake the built environment. Nuclear power plants would become a liability. Everything would crumble until bits of plastic, glass, the Hoover dam, and a distorted climate are all that is left of humankind.