Figure 2

Extinctions per thousand species per millennium. This figure, taken from the Millennium Ecosystem Assessment, shows the estimated average lifetime of species in particular groups of animals, at different periods. 'Distant past' refers to average extinction rates as estimated from the fossil record. 'Recent past' is for extinction rates calculated from known extinctions of species (the lower estimate) or known extinctions plus 'possibly extinct' species (upper bound) over the past century or so. 'Future' extinctions are derived from a variety of different models, all based on current trends, but considerably uncertain (as indicated by the wider range).