When the first episodes of Planet Earth were broadcast in the UK, the producers were criticised by some green campaigners for glossing over the environmental problems faced by the planet. Executive producer Alastair Fothergill defended the approach, explaining that a heavy-handed environmental message would not work on primetime BBC One. However, the Planet Earth film crews witnessed first-hand scenes of environmental degradation and the increasing scarcity of wildlife in some of the shooting locations. This experience formed the basis of Planet Earth - The Future, which was designed to engage viewers in a mature debate about environmental issues. By choosing to air it on BBC Four, a recently-created digital channel with a highbrow reputation, the series only reached a small audience, in contrast to the viewing figures for Planet Earth itself.