I love plants; in fact, i prefer the company of plants to that of people and i consider our green companions the higher life form. So when i saw Eating the Sun: How Plants Power the Planet (Oliver Morton) staring at me from a shelf in the bookstore, i caved. I didn’t even need the jacket blurbs making statements like, “A book that may reorder the way you think about the world…” (The Economist). I was after the advertised “…complete biography of the earth through the lens of this mundane and most important of processes [photosynthesis].” My expectations were high. Mr. Morton exceeded them with massive amounts of historical and scientific information rendered in rich prose.
We’ve been living with plants for the entirety of human history. We’ve corralled some of them, and co evolved with those for more than 10,000 years. By 1771 Joseph Priestly knew that plants thrived in air that killed animals and flames, because he saw it with a sprig of mint in a bell jar. He also figured out that if he used up all the air in the jar with a candle he could make the jar candle worthy again by keeping the mint in it. Priestly ended up creating carbonated water and prompting Benjamin Franklin to say, “That the vegetable creation should restore the air which is spoiled by the animal part of it looks like a rational system.”
The rationality of the system was no longer in doubt, but the mechanisms underlying the system would not be understood until the atomic age.
Morton weaves his tale of photosynthesis through the warp of the scientists who did the discovering. His story explores the creation of UCal Berkeley’s Rad Lab, the search for a good carbon isotope to measure time, the Manhattan Project, and the personal lives and politics of the scientists involved while staying focused on the underlying issue of photosynthesis. Rubisco, the Calvin-Benson cycle and the other facets of photosynthesis make their entrances historically. It is almost incidental to the story that the reader gets a solid grounding in the science of photosynthesis along the way.
Photosynthesis is what makes the heat differential between the sun and the earth work. Without plants, the land would warm more than the sea and the tropics more than the poles; the wind would still blow but there would be no life. And while life appears to break the Second Law of Thermodynamics, it doesn’t. It uses the Second Law to get a lot of work done, with plants being the heavy lifters. Photosynthesis uses sunlight to power chemical reactions rather than heat something up. Because photosynthesis doesn’t work thermally, it is not limited by the temperature difference between the leaf and its environment. It is limited by the difference between the temperature of the leaf and the temperature of the sun…or as the world around us exemplifies, it is hardly limited at all.
Section two deserves to be a book of its own. While Morton does an amazing job of covering the evolution of life on earth, and hence the evolution of the earth, in 164 pages, i found myself wanting more. Morton starts from the beginning, billions of years ago and marches through the millennia as surely as Life itself, exposing the reader to the many theories of how we got where we are today. And he writes well enough to create a mental picture of worlds ancient enough to be alien. The story is as entertaining as it is educational.
The eduction of the second section lends weight and power to the third section where Morton moves into the modern world and discusses environmental issues. Though not without gloom and doom, i found his treatment of our current predicament significantly different from the norm. Not only is the issue tempered by an understanding of the big picture and the incredibly long time-line, but possible solutions arise organically, like the plant life that the book revolves around.
Morton never proposes an answer directly. None-the-less, his answer is there and it is the answer that Nature stumbled onto long ago when a large eukaryote ingested a photosynthetic cyanobacteria but didn’t digest it. (And to be precise, “Not one particular species. One particular creature, at one particular place in space and time.” 206) The bacteria was eventually internalized completely, becoming part of the eukaryote. Which meant that the eukaryote never had to go looking for food again, and the hydrogen economy was born. The fuel of life is ATP, which is created at the end of the photosynthetic system by hydrogen ions being driven through a protein gateway as a result of chemiosmotic pressure.
We tend to think of our fuels as carbon based, but we have no use for the carbon…hence its being expelled into the atmosphere to combine with oxygen and create CO2. What we’re after is the hydrogen that got trapped along with the carbon. Natural gas (methane) is the cleanest burning fossil fuel because there are four hydrogen atoms for every carbon atom, CH4. Photosynthetic efficiency is low, 6%, compared to the efficiency of a photovoltaic array, 10-20%. On the other hand, it works just about everywhere, needs less solar radiation to operate, and photosynthesis happens to use our waste as a raw material.
Morton only hints at the possibilities being explored, most significantly by a group called Solar-H in Europe. The idea is to find ways to use, or artificially mimic, nature’s solution for powering the planet: the photosynthetic hydrogen economy. It is right that he only hints, because the book isn’t about hydrogen or the environmental issues we face. The book is about plants, wonderful, glorious plants. It is a high tribute to their mundane complexity that will change the way you look at the world oustide your window.
Eating the Sun: How Plants Power the Planet; Oliver Morton; HarperCollins, 2008; ISBN: 978-0-00-716363-9
The book itself:
First US edition, case bound (glue). The backup looks stellar, and the binding work is very well done: nicely milled and no pushup…though a signature in the middle is slightly out of jog at the head resulting in a 1 mm face margin difference in that sig. It might have been time for new trimmer blades.