Review: Light to Life: The hidden powers of photosynthesis and how it can save the planet
Key theme(s):
Media Type: Book
Title: Light to Life: The hidden powers of photosynthesis and how it can save the planet
Author: Raffael Jovine
Year of Publication: 2022
This book didn’t contain the science I was expecting, but the science it does contain provides a new way of looking at things (and a lot of other stuff).
There’s a quote from Paul Nurse on the front cover of this book that goes like this:
Read this book and you will learn how photosynthesis was discovered, how it works and how we can produce more food to feed the world.
I’m certainly on board with the first part of this claim, and it’s a fascinating history that I didn’t really know much about. Photosynthesis is one of those things that you learn about at school and that you never really question. It doesn’t have a neat little origin story like Newton’s apple or Archimedes’ bath. Like most science, it was a slow and winding path full of dead-ends and false turns (did you know people used to think plants ‘ate’ soil?), and it’s a story that is laid out really beautifully in this book. It perfectly demonstrates how ideas in science can be slow-burners, and how they can pass from generation to generation, being slowly refined into a workable theory along the way.
I don’t entirely agree with the second part of the quote, however.
The exploration of how the process of photosynthesis actually works is somewhat superficial. I’ll be honest, when I picked up this book, I was expecting it to go into the details of the actual physical/biological/chemical science of just how the sun’s energy is absorbed and used and maybe even into attempts to replicate the process artificially, but that’s not what this book is about. This may be because the actual process is extraordinarily complicated, and requires an understanding of one of the most counter-intuitive principles in quantum physics - the uncertainty principle.[1] Given the overall argument that the book is seeking to make, this level of detail may be an unnecessary distraction.
Because instead of focusing on photosynthesis as the ‘ground’ level (no pun intended) within individual leaves, this book frames photosynthesis as a broader, planetary-scale process, and also details some really - at least to me - unfamiliar forms of photosynthesis. It considers the impact of the process as expressed in the planet’s ‘Net Primary Productivity’ or NPP, defined as:
…the total amount of photosynthetic activity minus the amount of carbon organisms use for their own metabolism. The NPP is the amount of carbon removed from the environment and stored in biomass in a defined timeframe.
(97-98)
Perhaps this way of thinking about photosynthesis is obvious to you, dear reader, but it was new to me. Beyond a very basic understanding that “more plants = more CO2 fixed from the atmosphere” (and conversely “less atmospheric Co2 = more plants”), I hadn’t really thought about how you would go about quantifying this ‘photosynthetic activity’. And to be perfectly frank, having just re-read the section that introduces NPP to make sure I hadn’t missed anything, I’m not really much the wiser.
And that is one of my criticisms of this book - it skims over quite a lot of detail.
For example, when describing how NPP is calculated, the only explanation given is that it is based on advances in technology (particularly satellite imaging) that can be used to estimate changes in the amount of plant matter on the Earth’s surface. And that does make a sort of intuitive sense, and the idea is backed up with highly credible sources. But the book itself left me with questions about how reliable this kind of calculation can possibly be, amongst other things, particularly in the finer details of the NPPs of different terrains. Of course, there’s always a fine line to walk between ‘enough’ and ‘too much’ detail in scientific writing, but I think this book errs too much on the simplification side, perhaps underestimating its readers.
It may also be that something in me really resists the idea of reducing hugely complex systems down to single metrics. For example, according to Stilling’s (1996) Ecology: Theories and Applications (cited in the booke), temperate grasslands have a mean NPP of 600 grams per square metre per year, compared to tropical rainforest’s 2200. Does that mean that tropical rainforest is almost four-times more useful than temperate grasslands? To be clear, this is not exactly the argument that Jovine is making, and I would not dispute his claim that:
The problem is that the highly productive natural habitats listed in the table above are being replaced by ones that are less productive. With the inexorable increase of industrial and urban developments, we are forcing overall NPP to reverse. (138)
Note that the word ‘productive’ seems to have quite a specific meaning here, referring to the ‘productivity’ of ‘Net Primary Productivity’, and I think that’s where these single-lens ways of thinking about the world fall down: Within a certain set of parameters, Jovine’s argument is entirely correct - more photosynthesis is a good way of reducing the amount of CO2 in our atmosphere, but that ignores the contribution that grassland, for example, makes to biodiversity, or to soil health or to a myriad of other vital factors.
Nowhere is this more evident than in the conclusion. I’ll confess to being a bit relieved to reach the final chapter - not because the book was difficult to read, but because the final chapter finally included some concrete actions for the reader. I read a lot of popular science, both for work and for pleasure, but it seems to be that popular science about the climate crisis has a particular duty to focus not only on what can be done but also on what you can do. Without wishing to get too into the weeds (no pun intended) of translation theory, one of the longest-standing ideas is that texts have different functions: ‘informative’ (communicating information), ‘expressive’ (communicating emotion) and ‘operative’ (persuading the reader to do something). Most popular science is primarily informative (for obvious reasons) and expressive (the best popular science also convinces you to engage with the topic at an emotional level), with perhaps a dash of operative (convincing you to do something in response to this information). For popular science on the climate crisis, though, I think most readers would expect the operative to play a significant role as well - in other words, people pick up these sorts of books because they want to know what they can do.
And what does Jovine want us to do?
Well, beyond the somewhat nebulous ‘change our mindsets’, there is a list of fairly ‘typical’ suggestions: “Make bird boxes, build beehives, take care of community gardens, or make clever pots and beds that can fit into urban spaces. Compost and make fertiliser from organic waste” (211). But the main thing he wants us to do is grow loads more plants, seemingly pretty much any type. Now, don’t get me wrong - as a passionate allotmenter and gardener, I’m fully on-board with people growing more of their own food, or even simply cultivating flowers to make their homes and neighbourhoods more pleasant places. But I also know that longer-term thinking is required when it comes to placing trees, for example - put the wrong type in your garden and it can drain the ground and cause subsidence to your house. Or you may cultivate the pips from your favourite type of apple at the supermarket, but the fruit it produces in 10ish years’ time are probably not going to be the same as the type you bought, and that tree may grow to be massive.
These sound like quibbles, and perhaps they are, but this section of the book felt like it had been put in as a bit of an afterthought and not thought through properly. This doesn’t detract from what is, overall, a very positive (and I hope galvanising) message. Certainly we should all be doing whatever we can, wherever we can, but I dwell on this because it seems to embody this attitude that one unit of photosynthesis is the same as another, and I just find this too much of an over-simplification.
I can see why Jovine focuses on this way of thinking though.
He runs a company (first mentioned on p. 181) that takes areas of coastal desert (NPP of desert and semi-desert: 90) and turns them into algal pools filled with seawater (NPP of algal bed and reef: 2500), which can then be used to cultivate useful products. Again, details are somewhat light here, but example products include pigments and vegan egg-white substitute, and also deacidified fresh water for more traditional agricultural production. Setting aside my previous comments about looking at the world through a single lens, I can’t deny that drawing down 2 billion tons of CO2 per year (achievable through a network of pond operators converting 0.5 of the 15-18 million square kilometres of hot desert worldwide) is an attractive proposition. I really think that I could have read an entire book about this project and the other innovative projects to which the book devotes a mere 13 pages (181-194). And I think the excursus on Borlaug’s work and the Green Revolution, as covered comprehensively in The Wizard and the Prophet, could probably go.
You may have noticed that I’ve not addressed the third part of the cover quote.
This is not by accident. I’ve never written a book, and I can only imagine the struggles that an author goes through to distil their life’s work and everything they think is important into a single coherent narrative. But to be frank, I struggle to see how the section about fertilisers and pesticides in agriculture really fits in with the overall argument about the power of photosynthesis as a planetary force. This isn’t to say it’s not interesting, but it’s also quite well-covered ground, and I don’t see that it feeds into the story about the innovative practice of algal-pool agriculture. Perhaps this is a failure of the imagination on my part, but as far as I understand, the issues addressed are not limiting factors for the algae ponds, so why devote so much space to it?
Incidentally, this emphasis on growing organisms, and particularly ‘primary producers’ (the living things that extract energy from sunlight and form the basis of food chains) is why I put this book in the ‘food systems & horticulture’ category, rather than ‘biomimicry and environmental science’. It sounds strange, but I had really never thought about photosynthesis as a sort of macro-process, like the water cycle or tectonic plate movements. And yet, the point of this book is that photosynthesis is just as important a process - and operating at just a significant scale - as these other, more visible mechanisms. This is certainly a valuable takeaway from this book for me, whatever else I may have said above.
So would I recommend reading the book?
To the extent that the first part of the book has shifted my thinking, or at least thrown a new perspective on a subject I thought I knew the key details of, yes, it’s an interesting read. However, if you’ve found my thoughts about the book somewhat rambling (or at least more rambling than normal), this reflects the fact that I struggle to find a common thread uniting the book into a single coherent proposition. There’s some really fascinating ideas and thoughts in there, but I think there could be greater clarity around what the overall point is, and this does let it down somewhat. So is it worth reading? Yes. Is it worth reading more than once? Maybe not.
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[1] Jim Alkalili explains this here, and his book Life on the Edge: The Coming of Age of Quantum Biology is another one that’s been sitting on my to-read pile for longer than I care to admit.
Takeaways for sustainability communicators
Don’t underestimate your readers’ desire to understand the technical detail of your argument or topic.
Think clearly about your overall point, and how each individual element feeds into it.
Remember that readers want to know what they can do not just what can be done.