Optimism

From The Edge's "Reasons to be Cheerful", asking 160 scientists and intellectuals for their thoughts :

ALUN ANDERSON
Senior Consultant (and Former Editor-In-Chief and Publishing Director), New Scientist

The Sunlight-Powered Future
I'm optimistic about…a pair of very big numbers. The first is 4.5 x 10ˆ20 (4,500,000,000,000,000,000,000). That is the current world annual energy use, measured in joules. It is a truly huge number and not usually a cause for optimism as 70 per cent of that energy comes from burning fossil fuels.
Thankfully, the second number is even bigger: 3,000,000 x 10ˆ20 joules. That is the amount of clean, green energy that pours down on the Earth totally free of charge every year. The Sun is providing 7,000 times as much energy as we are using, which leaves plenty for developing China, India and everyone else. How can we not be optimistic? We don't have a long-term energy problem. Our only worries are whether we can find smart ways to use that sunlight efficiently and whether we can move quickly enough from the energy systems we are entrenched in now to the ones we should be using.........