Sir David Attenborough FRS is the world's best known naturalist and famous as a superb BBC wildlife broadcaster (see Wikipedia: http://en.wikipedia.org/wiki/David_Attenborough )..
Sir David Attenborough FRS (Royal Society coral working group co-chair), co-signatory to the statement by the technical working group on coral, The Royal Society on 6th July 2009: "The Earth’s atmospheric CO2 level must be returned to <350ppm to reverse this escalating ecological crisis and to 320ppm to ensure permanent planetary health. Actions to achieve this must be taken urgently. The commonly mooted best case target of 450ppm and a time frame reaching to 2050 will plunge the Earth into an environmental state that has not occurred in millions of years and from which there will be no recovery for coral reefs and for many other natural systems on which humanity depends. Working group signatories Professor John Veron (Coral Reef Research), Dr Mary Stafford-Smith (Coral Reef Research), Prof. Ove Hoegh-Guldberg (University of Queensland) [and 20 other eminent scientists]". [1].
[1]. Output of the technical working group meeting, The Royal Society, London, 6th July, 2009, “The Coral Reef Crisis: scientific justification for critical CO2 threshold levels of <350ppm”: http://www.carbonequity.info/PDFs/The-Coral-Reef-Crisis.pdf .