"In an authoritative and ominous warning, the 2010 Living Planet Report of the World Wide Fund for Nature (WWF), the definitive survey on the state of the planet's health, signals that tropical ecosystems are being degraded and tropical species are declining at an increasingly rapid rate, with the world's population now consuming the output of one-and-a-half sustainable Earths." "If we continue with 'business as usual', the report says, humanity will need the capacity of two Earths to absorb greenhouse gas emissions and keep up with natural resource consumption by 2030. "