Symphony in C Carbon and the Evolution of (Almost) Everything

Many works of popular science claim to be histories of almost everything or everyone, but earth scientist Robert M. Hazen might actually be in the position to stake that claim. Whether you are talking stellar evolution, the origin of life, organic chemistry, synthetic materials, or hydrocarbon fuels – the multifaceted atom carbon is ubiquitous and pervasive. Symphony in C is a whirlwind tour through geology, biochemistry, and evolutionary biology that is an incredibly absorbing read, although in places it almost comes apart at the seams under the intensity of its enthusiasm.

As executive director of the Deep Carbon Observatory or DCO, a decade-long global research programme on carbon that was initiated in 2009, Hazen is uniquely positioned to write this sweeping overview. The story of how this came off the ground is a thrilling reminder that fundamental research is not dead yet and that the right person in the right place can unleash incredible energy and momentum in a research community. You would be forgiven for thinking that this book closely mirrors the research goals of the DCO, reporting its outcomes for a lay audience. The DCO features prominently throughout, but Symphony in C is instead loosely structured around the analogy of a musical symphony in four movements (Hazen is also a lifelong musician).

The first two movements, Earth and Air, tackle technical topics such as mineralogy and atmospheric chemistry – generally speaking not the kind of subjects that will electrify audiences. What a treat, then, to find Hazen writing sections that I cannot call anything else but riveting.

“Earth” traces the formation of our planet and its minerals, highlighting the surprising finding that many mineral species are incredibly rare. Not only has there been an ambitious project to build a global mineral database (going by the unlikely name of RRUFF), but scientists have even used mathematical models to estimate the number of “missing minerals” yet to be discovered. Similarly, Hazen makes topics such as X-ray crystallography accessible, revealing the unexpectedly different mineral world existing in the high-pressure environment of Earth’s interior.

The story of Earth’s atmosphere is one of drama and fascinating questions. Drama in the form of the obliteration of Earth’s early atmosphere during the cosmic collision that formed our moon (see also The Big Splat). Fascinating questions in the form of the deep carbon cycle and whether the amount of carbon descending into Earth’s interior (e.g. through subduction or sedimentation) is balanced by what comes back up (e.g. through volcanoes).

Movement three, Fire, is a complete change of pace. In a mere 30 pages, Hazen gives a brief overview of carbon’s role in all our stuff. From fuels to synthetic materials, carbon’s physical properties make it eminently suitable to a very wide range of applications, with nanotubes and graphene sheets promising a future of even strong and thinner materials. This section seems to have little to do with the DCO research programme, and there is no mention of the people behind the science or of particular breakthrough experiments. Instead, Hazen writes a pop-science section that reminded me of Miodownik’s recent book Liquid.

The final section, Water, is the proverbial crowd-pleaser, exploring the for many fascinating topic of the origin of life and the role of carbon in it. Hazen reveals himself to be a nuanced thinker who prefers not to fall into the trap of false dichotomies. Did life start in the heat of deep ocean volcanic vents or in shallow pools of water lashed by lighting (as per the famous Miller-Urey experiment)? Hazen favours the idea that there is truth to all of these mechanisms, that “early Earth was an engine of organic synthesis”. Equally fascinating is the question “why carbon?” This question was also asked by Charles Cockell (see my review of The Equations of Life), and Hazen gives a slightly less physics-heavy overview of why carbon’s atomic properties make it such a versatile and therefore useful building block for life.

This last section feels like the frenetic overture to Hazen’s symphony as the evolution of life added many layers and subtleties to Earth’s carbon cycle. From the surprising abundance of microbial lifeforms at great depths (see Deep Life), the mineral-microbe interactions that kick-started life (see Life’s Engines), the colonisation of land by plants and then animals (see The Emerald Planet and Your Inner Fish), the formation of most of our planet’s fossil fuel reserves during the Carboniferous (see my review of Carboniferous Giants and Mass Extinction), or radiocarbon dating (see Hot Carbon) – this is the section where Hazen packs in topics that have received book-length treatments elsewhere. There are so many interesting things to tell here that the narrative almost derails under its own intensity.

Throughout, Hazen introduces the many researchers, past and present, who are behind the findings. A review in Nature faulted the book for leaving out certain historic figures, something I cannot really comment on given my unfamiliarity with the topic. Hazen does mention the story told here is inherently personal – “many symphonies of C are waiting to be written”. What I found missing were illustrations. The unnumbered colour plate section is a bit of a grabbag of useful diagrams and photos of scientists at work, but the text never refers to it, leaving the reader to figure out when to consult the plates. Illustrations in the body of the text could have been used to show certain concepts that are now described at length.

Symphony in C covers a vast range of topics, possibly at the risk of losing its structure. Although the narrative-as-a-symphony idea is original and Hazen can really run with it given his background, I did not feel it always worked. The saving grace that prevents this book from becoming a jumbled list of facts is Hazen’s excellent writing. I simply struggled to put the book down! I found the first two sections particularly eye-opening as they dealt with disciplines I am less familiar with. Interestingly, Cambridge University Press will publish Deep Carbon later this year, an edited collection on the DCO’s research written for an academic audience. If that book looks too intimidating then Symphony in C is exactly your ticket to understand why carbon is at the heart of pretty much everything.