SYMPHONY IN C

An appealing popular-science account of carbon, the “giver of life.”

According to this lively, expert overview, although carbon is only the fourth most abundant element in the universe—and second in the human body—it is the key to everything. Hazen (The Story of Earth: The First 4.5 Billion Years, from Stardust to Living Planet, 2012), executive director of the Deep Carbon Observatory at George Mason University, emphasizes that “carbon, by itself, and in chemical combinations with other atoms, provides unmatched cosmic novelty and unparalleled potential for cosmic evolution….As the basis for all biomolecules, no other element contributes so centrally to the well-being and sustainability of life on Earth, including our human species.” The author divides the book into a symphony of four movements, each entitled with a classical element: earth, air, fire, and water. “Earth” begins with the universe itself. Carbon, essentially absent after the Big Bang, first appeared in the cores of massive stars, spreading across the universe when those stars died and exploded in supernovae. Our planet formed 4.5 billion years ago from dust and rocks in a protoplanetary disc rotating around the young sun. Extremely hot at first, as it cooled, heavy elements (mostly iron) sank, taking most of the carbon, but plenty remained in the “Air” as carbon dioxide engaged in the essential carbon cycle, shifting between atmosphere and ocean, plunging deep into the Earth and then emerging through volcanoes. Readers expecting to learn how massive amounts of extra carbon dioxide from the human burning of hydrocarbons are destabilizing the cycle will not be disappointed. In “Fire,” Hazen, a smooth stylist, reminds us that carbon remains our major source of energy but also the source of almost everything we use, from shampoo to the soles of our shoes. “Water” is essential for life, at least on Earth. Scientists disagree on how life began, but few doubt that only carbon, with its supreme ability to link with other elements, makes it all possible.

A skillful account of the central element in our lives.