'Great Dying' in Americas perturbed climate

Colonisation of the Americas at the end of the 15th Century killed so many people, it disturbed Earth's climate - a new study shows. The disruption that followed European settlement led to a huge swathe of abandoned agricultural land being reclaimed by fast-growing trees and other vegetation, and this pulled down enough carbon dioxide from the atmosphere to eventually chill the planet. Our science correspondent Jonathan Amos spoke with study authors Mark Maslin and Chris Brierley.