According to the "Global Biodiversity Outlook 2", a report released by the United Nation's Convention on Biological Diversity, we humans are currently responsible for the 6th major extinction event in the history of the Earth, and the greatest since the dinosaurs disappeared, 65 million years ago. The other four extinctions were about 205, 250, 375 and 440 million years ago. Scientists suspect that asteroid strikes, volcanic eruptions or sudden climate shifts may explain the five. It estimated the current pace of extinctions was 1,000 times faster than historical rates. Other conclusions in this report:
1) 2/3 of the services provided by nature to humankind are in decline, worldwide;
2) demand for resources globally exceeds the biological capacity of the Earth by some 20%;
3) the average abundance of species declined 40% between 1970 and 2000 while species in species in rivers, lakes and marshlands have declined by 50%.