The first thing I did when this book landed in my hands was to search the index for a name. It wasn’t there.

The name I sought was Peter Vitousek. He was the lead scientist in a landmark study of how much of the sun’s energy humans appropriate for their own use. The answer, back in the 1980s, was 40%. A book called Eating the Sun must be about the fact that ultimately humanity, and almost all life on earth, depends on the ability of plants to capture solar energy and store it in a form that the rest of life can use. That book would, I imagined, have a result like Vitousek’s at its core. If fewer than five billion people were already using 40% of primary productivity, what is double that number going to eat in 50 years time?

But that is the book in my imagination, not this. Oliver Morton has chosen, by his own admission, to write three books in one. The first is about how scientists came to appreciate the working machinery of photosynthesis, the process by which plants capture sunlight. The second is about the ways in which the history of our planet (and other planets) has been, and always will be, intimately tied to photosynthesis. The third is about the near future, and the “carbon/climate crisis” as he prefers to call it. Each informs the others, to some extent, but with a little filleting each would also stand alone, and perhaps a lesser writer would have gone for three safer, smaller books. Morton is not one for safe and small.

He gives us the big picture, and no mistake, whether he is tunnelling into the extremely intricate workings of the molecular photo-synthetic machinery or striding over the South Downs to explain the planet’s long journey from the almost lifeless waters of the late Permian ocean (250m years ago) via the shallow seas of the Cretaceous (100m years ago), through the rise of the grasses (8m years ago) to the Battle of Lewes (271,549 days ago, as I write). At times this tendency makes for jarring disjuncts, as one swoops from electron transfers to a lyrical cycle ride to the Cambridgeshire garden of a photosynthesis pioneer. Overall, though, I enjoyed this book as much for the crazed asides as for the upsetting insights: turning Joni Mitchell’s line about “we are stardust, billion-year-old carbon”, beloved of a certain set of science writers, into biology longa geology brevis is rather good. The point being that rocks don’t generally last as long as life.

There are many more similar insights and happy phrasings. The idea that oil and coal and natural gas are stored sunlight has become almost hackneyed, Morton wants us to think of radioactive uranium as stored starlight, because it is made by the explosion of a star large enough to become a super-nova. He casually mentions that we spend fully 2% of our civilisa-tion’s energy budget on making nitrogen fertilisers for our crops. Alas, 2% of an unimaginably large amount remains pretty unimaginable.

I didn’t know that alamois Spanish for poplar, a favourite tree of biofuel boosters. Casually dropping the little factoid that the mesa on which Los Alamos, the facility, sits is surrounded by los alamos, Morton makes his clarion call for a vast and directed scientific effort, a Manhattan Project for the solar age, one that will explore a plurality of options in search of truly renewable energy (and the fuels to store it), and that will allow the entire global population to live like Californians.

It will, he concedes, require great scientists to work to change the world, not merely to understand it. The stick is the probable extinction of our way of life. The carrots are survival, and money, and one buys the other. “Though scientists follow their curiosity, they will follow the money, too, when there is enough of it,” Morton writes. He also approvingly quotes Tom Paine: “We have it in our power to begin the world over again.”

This, in the end, is where the detailed understanding of the inner workings of photosynthesis gain importance, for how can we change the world, as required by book three, if we have not understood it, as book one asks us to? I do wonder, though, whether the big picture of molecular machinery might possibly put some people off. There are people – Morton as writer, clearly; me as reader, fortunately – who thrill to the details, the historical accidents, the illuminating incident. But many people who would definitely enjoy and find useful book three, and probably book two, will, I fear, be put off by book one.

For them, some advice. If you find yourself skimming Eating the Sun in a bookshop, and you come across one of those scientific graphs, off-putting even with their avowedly user-friendly hand-style lettering, ignore it. Indeed, ignore the whole of book one, if you prefer. That way you can avoid the fascinating detail of photosynthesis, avoid an apoplexy provoked by the realisation that a writer as talented as Morton doesn’t know the difference between a pestle and a mortar, avoid the remembrance of long-forgotten biochemistry lectures, and enjoy an informative, fascinating and thought-provoking read.

Vitousek does, in fact, get a look in, in a note on further reading for a shortish paragraph in the penultimate chapter. And dare I say it, while Eating the Sun is a fine work and a good read, I’d still like to read the book I originally imagined it might be. What are the 10 billion going to eat?

Eating the Sun: How Plants Power the Planet by Oliver Morton

Fourth Estate £25 pp384

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