New Studies Suggest Onset of Sixth Major Mass Extinction

New evidence suggests that the Earth is on the verge of its sixth major mass extinction — the last one having occurred 65 million years ago, wiping out the dinosaurs. This one is likely to be caused not by a meteorite, say researchers, but by habitat destruction resulting from human activity. Two U.K.-based studies in the current issue of the journal Science prompted the speculation. One was a study of butterfly populations in the U.K. involving more than 20,000 volunteers and data gathered over a 40-year period. The second was a study of plant biodiversity in U.K. grassland sites. Both studies came to similar conclusions: Species are declining and dying off like it’s going out of style. While we haven’t reached the 65 to 95 percent death rates of previous mass extinctions, the numbers are increasing rapidly. With regard to biodiversity, says grasslands study author Carly Stevens, “If you keep taking enough bricks out of the wall, the wall’s going to fall down.”