Comparing extinction rates: Past, present, and future

Abstract

The last centuries were marked by a steep increase of human population and by the intensification of anthropogenic impacts on ecosystems and natural communities. Today, the rate of species extinction is almost two orders of magnitude higher than the natural background extinction rate, and may escalate one or two orders of magnitude further according to the projections of future extinctions. If realized, projected extinction rates would be comparable to the extinction rates during past mass extinctions. This article looks at past, present, and future rates of extinction for a critical discussion on the severity, potential risks, and uncertainty associated with current and projected rates of extinction.