Richmond, Surrey 8 May 2014 Dear Professor Guillebaud Thank you for your invitation to share in the 20th anniversary of the Environment Time Capsule project at Kew Gardens on World Environment Day, Thursday 5th June. I should have liked very much to come, but unfortunately I have to be abroad filming at that time. I am sorry - particularly so because, in fact, I have already helped to bury one time capsule at Kew, less than 200 metres away from yours, in the foundations of the Princess of Wales Conservatory while it was under construction. Both include objects from our time for the interest of people in the future, and both convey our interest in and concern for the sustainability of the planet that they will inherit from us. I agree very much with your central concept that many of the world’s most grievous afflictions can be attributed to population growth: the unprecedented increase in numbers of one species – humans – whose environmental impact threatens the habitats and the very existence of nearly all others, in both the animal and vegetable kingdoms. This process certainly cannot continue indefinitely without bringing about global catastrophe. When the facts are incontrovertible and the conclusions inescapable; when success could bring a vast improvement in the welfare and happiness of millions; and when the penalty of failure is global disaster: surely humanity will want to collaborate and make sure that sanity prevails.   from Sir David Attenborough CH, FRS