The Living Planet Report is World Wildlife Fund’s (WWF) periodic update on the state of the world’s ecosystems. Even a cursory reading of the report should be enough to get a sense of the scale of the current ecological crisis and the catastrophe which it could lead to. 

http://www.panda.org/news_facts/publications/living_planet_report/lpr_2008/index.cfm

http://www.scribd.com/doc/8040885/Living-Planet-Report-2008