Environmentalists are fiddling while Rome burns," says Vinod Khosla, founder of Khosla Ventures, a Silicon Valley venture-capital firm. "They get in the way with silly stuff like asking people to walk more, drive less. That is an increment of 1-2% change." Forget today's green technologies like electric cars, wind turbines, solar cells and smart grids, in other words. None meets what Mr Khosla calls the "Chindia price"-the price at which people in China and India will buy them without a subsidy. "Everything's a toy until it reaches that point," he says. Mr Khosla has a different plan to save the planet. He is investing over $1 billion of his clients' money in "black swans" -- ideas with the potential for sudden jumps in technology that promise huge environmental benefits, easy scalability and rapid payback. The catch? Mr Khosla expects nine out of ten of his investments to fail. "I am only interested in technologies that have a 90% chance of failure but, if they do succeed, would change the infrastructure of society in some radical way," he says. Khosla Ventures' portfolio reads like an eco-utopian wish-list: diesel from microbes; carbon-negative cement; quantum batteries; and a system for extracting methane from coal while it is still underground.