"The last thing I’d want to get reincarnated as is a caterpillar," says David N. Karowe. He doesn’t have anything personal against caterpillars; it’s just that the future doesn’t look very rosy for the fuzzy leaf chewers. Increased malnutrition, attacks by parasitic wasps, and death rates await caterpillars in the coming decades, predicts the entomologist, who’s at Western Michigan University in Kalamazoo. The ultimate perpetrator of the anticipated tribulations of these and other insect herbivores is a change in Earth’s atmosphere. The concentration of carbon dioxide (CO2) in the atmosphere has risen steadily since the beginning of the industrial revolution and is expected to double from today’s global averages in the next 50 years. While scientists continue to debate whether elevated concentrations of CO2 and other greenhouse gasses, such as methane, will lead to significant changes in Earth’s temperature, they agree on one thing. Boosting atmospheric CO2 makes plants grow faster. Paradoxically, that effect could spell disaster for plant eaters, from caterpillars to antelope, as well as the animals that dine on these herbivores, new research suggests. Fast growth often leads to poor nutritional value.