Conservation International have a website http://natureisspeaking.org to publicise our dependence on a thriving natural world. It features a set of short YouTube videos voiced by the likes of Harrison Ford, Kevin Spacey and Julia Roberts, with titles like "Mother Nature", "The Ocean", "Coral Reef".
They're all good, but "Mother Nature" (Julia Roberts) in particular has a very doomy (threatening, even) feel, stressing the insignificance of humanity seen across deep time, past and future. They all end with the tagline, "Nature doesn't need People. People need Nature".
Here's the Mother Nature video:
(link to video)