apparently. when you asked about this earlier my favourite film is elf. sir david attenborough has called on the world's richest nations to meet their moral responsibility by helping the most vulnerable survive the effects of climate change. the 95—year—old naturalist and broadcaster called for immediate action to address some of our biggest environmental challenges. he's been speaking to our science editor david shukman during the filming of a new documentary series, the green planet, which will be aired next year on bbc one. this is a thermal camera. and it will tell me the difference between the surrounding temperature and the temperature in the centre of a daisy flower. the surroundings — 12 degrees. in the centre of the flower — 21.