Gideon Rachman looks at how two icons of business and film – the legendary nature director David Attenborough, and Microsoft founder and global philanthropist, Bill Gates approach climate change.

Sir David, now in his nineties, uses his position as one of the world’s most famous broadcasters to sound the alarm about a looming environmental catastrophe. In a recent BBC documentary, Climate Change: The Facts, he argues that without dramatic action, humanity “faces a devastating future.”

Mr. Gates, says Rachman, is also very concerned about climate change, but has a more upbeat view of the future. “It’s better to be born today than ever,” Gates told the MIT Technology Review. Gates avoids doomsday scenarios, preferring instead to focus – and invest – in the “ingenious inventors who are tackling climate change.” He has contributed $1 billion to fund scientific research into alternative energy, and is co-chairing the Global Commission on Adaptation, which aims to mitigate the effects of climate change on the world’s poorest people.

So, who is right, Rachman asks?

“I suspect that Mr. Gates is correct to believe that technological advances can eventually solve or mitigate many of the problems caused by climate change. But I am afraid that Sir David is right to fear that these technological breakthroughs will come too late to prevent tragic damage to the natural world. The unresolved question is whether change will come fast enough to protect humanity itself.”

For investors it makes sense to pay attention to the advice of both. Capitalize on the opportunities that Gates envisions, yet be prepared for the worst of Sir David’s doomsday views.