The video was introduced as coming from the one man on the planet smarter than Gates.
Fade to black. ... And there was Hawking on the big screen, speaking to Davos via his familiar synthesised robot voice.
Hawking began with a joke: "He's not quite as good looking as me."
![Stephen Hawking](https://static-ssl.businessinsider.com/image/54c29553dd08952f758b45d5-1200-924/stephen-hawking-2.jpg)
Jim Edwards / Gates Foundation video
"I am very aware of the passage of time. Seize the moment. Act now," Hawking said. "At one point I thought I would see the end of physics but now I know that the wonder of discovery will go on."
Humanity needs to slow down global warming, invest in renewable energy and clean water, he said. "We are all travelling through time. Let us make the future a place we'd want to visit."
![Melinda and Bill Gates](https://static-ssl.businessinsider.com/image/54c29554dd08952f758b45d6-666-502/20150123_183304.jpg)
Jim Edwards
Melinda and Bill Gates at Davos.