Ecological doomsday: a large, dense, occasionally frightening Message-novel from the British author of This Sentient Earth. In 1990, the ocean's oxygen-producing plankton are dying from pollution, and maverick oceanographer Theo Detrick predicts a disastrous drop in the air's oxygen content within 20 years. Nobody believes him, of course: powerful polluter-industrialist J. E. Gelstrom is furiously empire-building; the US/USSR military have abandoned nuclear weapons for a better deterrent--environmental warfare. So marine biologist Gavin Chase teams up with Detrick's daughter Cheryl to gather facts and alert the public to the danger. Soon, though, the world climate warms, the protective ozone layer thins, and the equatorial regions become poisonously uninhabitable. The military, led by maniacal Major Madden, unleashes its environmental weapons while retreating to secret, sealed labs in order to breed mutant monsters capable of surviving in the new, anaerobic conditions. But eventually the dying Gelstrom has a change of heart and gives funds to Chase and friends. . . who work desperately to reverse the ecological transformation. Hoyle's ear for American dialogue (the primary brand of talk here) is nonexistent. His narration is sluggish, weighed down by self-conscious Message-mongering. But the apocalyptic premise here is just-about-plausible--and in the final 100 pages Hoyle's rather morbid imagination propels matters to a fairly tense and absorbing conclusion.