When you burn a log in the fireplace it burns to carbon dioxide and water, and a bit of ash. It was carbon dioxide and water in the forest, and, with the help of sunlight, the tree made it into wood. It threw the oxygen out as waste and left the sunlight inside. Then you, with the help of the oxygen in the air, burn it back to carbon dioxide and water, and the sunlight heats your house.

The many things that we think we do, really we don’t. They are all driven by the energy of sunlight. When you watch a football game, it’s just sunlight recycling itself on the football field.

And my steps, when I walk the [Golden] Gate Bridge, are similarly driven by the energy of sunlight. They are driven by the oxidation of the reducing agents made, with the energy of sunlight, by the plants in the wheat fields of Kansas, in the vineyards and pastures of California, and in the pineapple plantations of the Philippines. They are driven by the sunlight on the orange groves of Florida and California, on the cane fields of Hawaii and Brazil, and partly by sunlight that fell on the ocean off Cape Cod.

Although the reducing agents which we eat may have come from far and near, they were made by the plants in the recent past, whereas the oxygen which we breathe has been thrown out as waste by all those green leafy things over the past hundred million years.