Giant, jagged earthwork berms should surround the area. Dozens of granite message walls or kiosks, each 25 feet high, might present graphic images of human faces contorted with horror, terror, or pain (the inspiration here is Edvard Munch’s Scream) as well as text in English, Spanish, Russian, French, Chinese, Arabic, and Navajo explaining what’s buried. This variety of languages, as Charles Piller remarked in a 2006 Los Angeles Times story, turns the monoliths into quasi-Rosetta stones. Three rooms—one off-site but nearby, one centrally located, and one underground—would serve as information centers with more detailed explanations of nuclear waste and its hazards, maps showing the location of similar sites around the world, and star charts to help intruders calculate the year the site was sealed.

It’s impossible to say what apocalyptic event might separate 21st-century Americans from our 210th-century successors. Successors, mind you, who could live in a vastly more sophisticated society than we do or a vastly more primitive one.

Across the U.S. as a whole, approximately 50 percent of the warming that has occurred since 1950 is due to land use changes (usually in the form of clearing forest for crops or cities) rather than to the emission of greenhouse gases.

Johnston’s ability to, essentially, stealth-worldbuild is impressive, making the growth of the story past the central mystery of Abi and Michael seem both natural and effortless, drawing the reader in without tipping his hand about what he’s doing, or even where he’s going next (Within the 300+ pages of the Apocalyptic Edition collection, there’re a couple of reveals that surprise but make sense and stand up to re-readings). Making the characters recognizable without making them too familiar – and, thankfully, staying clear of cliched fake-swearing or language which shows that the writer is trying a little too hard to tell us that this world is different, really – he manages to pull our sympathies towards his characters while still giving them the space to surprise and make the wrong decisions without losing our interest or empathy.