From Mr Paul Hohnen and Mr Allen White.

Sir, The UN Millennium Ecosystem Assessment should be compulsory reading for governments, citizens and business everywhere ("World's ecosystems are in danger, UN warns", March 30). The threats it describes are not new, but are compellingly linked and laid out. The conclusions are bleak. Sixty per cent of the global ecosystem services examined are currently degraded or used unsustainably. Abrupt ecosystem collapses are increasingly likely. The world's poor are suffering already from adverse changes, and wealthy populations cannot be insulated.