Quotes of the Day

For a substance that is the basic building block of life as we know it — without it, our planet might be little more than a dull rock — carbon has gotten a bad rap lately. Bound to two atoms of oxygen, it creates carbon dioxide, the chief greenhouse gas that has kept our planet warm for billions of years — and is now, thanks to human activity, making us too warm. When we think of carbon, the first word we associate with it is emissions, a concept that evokes a tinge of illegality, as if emitting a mere molecule of CO2 were a crime. But as Eric Roston points out in his engaging new book, The Carbon Age: How Life's Core Element Has Become Civilization's Greatest Threat, C is about more than just CO2. "If you think about carbon only in terms of climate change, you're missing out," he says. "If you want to learn about the world, the fastest way is to follow the carbon." (Listen to Roston talk about carbon and his new book on this week's Greencast.)

A senior associate at the Nicholas Institute in Washington, Roston says carbon began to pique his interest several years ago when he was a reporter at TIME magazine, focusing on energy-related business and technology. He found the word popping up everywhere — in stories about climate-change issues, of course, but also in those about low-carb diets or even the ultra-light carbon bike that Lance Armstrong rode when he won the Tour de France. "Everywhere you looked, you had these stories that dealt with carbon," Roston says. "I wanted to get context on it, to get some understanding on the work I'd been doing." Propelled by what he calls a "foggy Star Trek sense that carbon is the central element of life and civilization," Roston left TIME and began to pursue his ideas.

The result is The Carbon Age, a kind of biography of the atomic element that is, as Roston points out, central to our world. "In anything bigger than an atom and smaller than a star, you're going to find carbon," he says. That includes all forms of life on the Earth, which is, as Mr. Spock used to say, carbon-based. That's because on a molecular level, carbon is a wonderful chemical joiner. Seemingly without prejudice, carbon atoms will combine with almost any other element to form the more complicated building blocks of life. "It's atomic Velcro," says Roston.

Beyond making up the bricks of life, carbon is virtually inescapable in industry as well. The plastics that can be found in everything from your chair to the space shuttle contain carbon — as does, of course, our energy supply. Our main fossil fuels — coal, petroleum and gasoline — are made up of carbon that has been compressed in the Earth for millions of years and we're now burning and rapidly restoring to the atmosphere. (The same process occurs when we burn wood in a fireplace.)

The sheer ubiquity of carbon is what makes eliminating greenhouse-gas emissions so difficult. But the surprising truth, Roston writes, is that we have actually been decarbonizing over time. Humanity's main fuel for eons was wood, which has a carbon-to-hydrogen ratio of 10 to 1 when burned; by comparison, that ratio is 2 to 1 for coal and 1 to 2 for oil. The problem is that we're burning ever larger amounts of fossil fuels, putting a greater concentration of carbon into the atmosphere than has been seen for millions of years. Though carbon has its positive points, even in the air — it feeds plants, and without the greenhouse effect, we'd basically be living in a climate like Mars' — Roston makes clear in the book's powerful conclusion the dire fate that awaits the Earth if we can't kick our carbon habit. That won't be easy. "There's never been a purposeful transformation in our energy system," he says. "We went to coal because it was better than wood, and we went to oil because it was better than coal." If we're going to cut out carbon, it's going to require a broad, dedicated policy, and it will take years. But we don't have much choice. As Roston's book shows, either the carbon age will end — or we might.

• Bryan Walsh