The collection begins with Paul McAuley’s “Elves of Antarctica,” about a helicopter pilot working for a huge industrial project intended to preserve Antarctica’s western ice sheet. This is probably the most scientifically plausible story in the set. It’s also one of the most didactic, explaining the altered world in a leisurely way that is perhaps meant to evoke the romantic haze Strahan mentions, though instead it just feels heavy-handed. A number of stories in the first half of the collection, like Ken Liu’s “Dispatches From the Cradle: The Hermit — Forty-Eight Hours in the Sea of Massachusetts,” fall into this territory: lovely yet disengaged travelogues of an environment in flux.

This starts to change with Christopher Rowe’s “Brownsville Station,” the slightly surreal tale of a train that travels along the “linear city” edging the coast between Cancún and Key West. Thereafter the collection gets less plausible but more intriguing and immersive, as in Jeffrey Ford’s “What Is,” an omniscient-narrated tale of stubborn, damaged people fighting a hopeless battle for survival in drought-destroyed Oklahoma. Nalo Hopkinson’s “Inselberg” features a mutant tour bus driver — of a living bus — ferrying entitled tourists through a terrifying and wondrous island landscape of sugar swamps and radioactive seas. By Catherynne M. Valente’s closing tale, “The Future Is Blue,” readers are far off the path of thinly veiled environmentalist lecture and deep into the strangeness of a world utterly transformed. Here, at last, is the romanticism that Strahan seeks — after a journey from science into the unknown that perhaps intentionally replicates the future to come. Altogether it’s haunting, heady stuff.

Mira Grant’s hit Newsflesh trilogy was an astonishing take on the tired zombie apocalypse subgenre — precisely because it was barely about the zombie apocalypse at all. It wore other hats: epidemiology thriller, genre-savvy black comedy and a fascinating exploration of the future of (not so) new media. Now the follow-up anthology RISE (Orbit, $25) covers the before and after of the novels, with several short stories set during the Rising, when the zombies first appeared, and others exploring the aftermath of “Blackout,” the trilogy’s conclusion. This is great for established readers, because it brings into sharp focus what is mostly elided in the core series. In “How Green This Land, How Blue This Sea,” an indirect sequel to the trilogy, readers are shown a different paradigm for survival in Australia’s environment-first response to the crisis. (The zombie kangaroos are a highlight.) “Countdown” introduces the personalities involved in the creation of the ­Kellis-Amberlee zombie virus, humanizing the researchers, the test cases and even the anti-establishment protesters who disastrously released the viral strains and thus initiated the apocalypse. All of this makes for a rich expansion on a beloved universe.

However, roughly half of the collection is set during the Rising itself, and these weaken the whole. Instead of nuanced examinations of the politics of fear, stories like “The Day the Dead Came to Show and Tell” and “San Diego 2014: The Last Stand of the California Browncoats” are what Newsflesh wasn’t: just zombie stories. They’re exciting, horrifying. They’re written with the same gripping attention to character and pace, and are just as darkly tongue-in-cheek as the novels (as a story about zombies versus San Diego Comic-Con cosplayers must be). Still, they lack the media analysis and complexity that made the trilogy so refreshing. New readers may come away thinking of this series as merely fun. They would do better to head straight for the trilogy, leaving the vast horde of longtime fans to devour “Rise” in the spirit it’s meant.