Dinosaurs’ extinction more complicated than mere asteroid impact

BBC : The extinction of the dinosaurs some 66 million years ago may have been caused by more than an asteroid impact. Other contributing factors, such as rising temperatures and sea levels and increased volcanic activity, may have made certain species more susceptible to extinction when the asteroid struck, according to a recent study by a group of 11 dinosaur experts from the UK, the US, and Canada. They say that although the dinosaurs showed no sign of long-term decline despite the presence of those environmental pressures, the timing of the asteroid strike made it particularly devastating. In fact, one of the experts, Steve Brusatte of Edinburgh University, says that had the asteroid hit Earth a few million years earlier or later, dinosaurs might still exist today.