The World Wildlife Fund has improved its methods of measuring the world's wildlife populations—and discovered that the situation is even worse than previously thought. In its Living Planet report, the numbers are stark: Populations of vertebrate species—including mammals, birds, fish, and reptiles—fell by a staggering average of 52% between 1970 and 2010, and the trend isn't slowing down. The population drop was 39% among both terrestrial wildlife and marine wildlife, and 76% among freshwater species, according to the report released in partnership with the Zoological Society of London. Researchers earlier estimated that around 30% of the world's wildlife had been lost over the 40-year period.
The report looked at more than 10,000 representative populations of wildlife species and found that habitat loss was causing the most damage, although the effects of climate change are becoming more apparent. "We're gradually destroying our planet's ability to support our way of life," warns WWF chief Carter Roberts. "But we already have the knowledge and tools to avoid the worst predictions. We all live on a finite planet and it's time we started acting within those limits." But the report wasn't unrelentingly bleak: The group was able to highlight a few successful conservation efforts, including growth in gorilla tourism in Rwanda and moves away from slash-and-burn agriculture in Brazil, the BBC reports.