Forthcoming book examines the role of humans in the eradication of species, and its findings are not likely to be pleasant. -- Scientists say the number of species being lost is approaching levels reached during five pivotal extinction events that have swept the planet over the past 600 million years. - Among these catastrophes was the event that wiped out the dinosaurs 65 million years ago. - Kolbert's task will to be show whether or not humanity – with its spiralling population, widespread habitat destruction, over-fishing and global warming – is rivalling these.