"Biodiversity has decreased by an average of 28 percent globally since 1970 and the world would have to be 50 percent bigger to have enough land and forests to provide for current levels of consumption and carbon emissions, conservation group WWF said on Tuesday."

"Unless the world addresses the problem, by 2030 even two planet Earths would not be enough to sustain human activity, WWF said, launching its 'Living Planet Report 2012', a biennial audit of the world's environment and biodiversity - the number of plant and animal species.

Yet governments are not on track to reach an agreement at next month's sustainable development summit in Rio de Janeiro, WWF International's director general Jim Leape said."

Tom Miles reports for Reuters May 16, 2012. [2]