Numbers Don’t Lie: 71 Things You Need to Know About the World, by Vaclac Smil

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Reviewed by Annabel

If you, or a potential recipient of this book for Christmas, are a fan of Tim Harford on BBC Radio 4’s More Or Less – a programme devoted to examining numbers and statistics to tease out the real facts – Smil’s book is likely to be a hit, doing much the same job on the page with some added history stirred in. The Czech-born Smil is Professor Emeritus at the University of Manitoba, where he taught environmental science amongst other courses, and has written many books.

Numbers Don’t Lie is compiled from 71 short essays, grouped into seven thematic sections: People; Countries; Machines, Designs, Devices; Fuels & Electricity; Transport; Food; and finally, Environment. Nominally an eclectic collection, they do broadly reflect Smil’s own particular interests and preoccupations.

First though, there’s a necessary introduction about the quality of data – its source, history, units, contexts, exchange rates for money etc. Smil’s data is taken from primary sources: globally respected organizations, national institutions, historical data from national agencies and papers in major scientific journals; footnotes give his favourite sources for the quality of their data. All that stated, we’re ready to go…

The first section, on People, contains a couple of particularly pertinent topics to our current Covid world: Smil was writing as the first lockdowns happened. In ‘The Best Return on Investment: Vaccination’ he looks at the cost-benefit ratio of vaccinations, Measles jabs showing a particularly strong benefit.  This is followed by ‘Why it’s difficult to predict how bad a pandemic will be while it is happening’ in which he explains why it is so difficult to measure global infection rates during a pandemic, as every country does things differently. On a more cheery topic though, this section also looks at height – a graph plots the tallness of 18-year-old Japanese men from 1990-2020 – they’re now averaging 12cm taller. But what is driving this increase?

Milk has been a key growth factor, be it in Japan or in the Netherlands. Before the Second World War, Dutch males were smaller than American men, but post-1950 US milk consumption declined while in the Netherlands it rose until the 1960s­–and it remains higher than in the US. The lesson is obvious: the easiest way to improve a child’s chances of growing taller is for them to drink more milk.

Some of the most interesting pieces for me came in the section on Machines, Devices, Design, especially the first chapter, which looks at ‘How the 1880s created our modern world’. Smil posits that this was the decade in which science really began to impact everyday life: Thomas Edison’s first power stations went on line, and Karl Benz started commercial motor vehicle production. Those may be key processes, but the 1880s also saw the introduction of the biro, Coca-Cola, skyscrapers and many more innovations.

Another fascinating essay, in the Transport section, was on modern car passenger to weight ratios. If you compare a small modern car with the latest airliner: the Mini Cooper with one passenger comes in at 16, a Boeing 787-10 with its maximum take-off weight giving a weight-to-payload ratio of 5.3.  How to reduce the ratio – have passengers! Better still ride a bicycle. Smil doesn’t shy away from controversy; electric cars are not green machines – yet. The electricity they use is too often generated from fossil fuels, let alone considering provision of charging points, plus the batteries are very heavy.

Smil also considers the impact of our increasing reliance on personal electronics (he is proud of never having owned or felt the need to own a smart phone). Apart from the environmental impact of their manufacture, every time we use them for anything, we are using electricity. It all adds up.  Alongside essays on more familiar topics in the energy, food and environment sections, this one did make me pause for thought – just think for instance of every e-mail newsletter you signed up for but delete without reading: all waste energy, not to mention tweets or fb posts you heart/like automatically… I could go on but won’t. Instead I will be unsubscribing to an awful lot of newsletters, and will try to curb my clicking finger.

There are plenty of figures and diagrams in this book, but they’re illustrative rather than complex; Smil sets them all into context and explains the numbers behind them in straightforward but decidedly enthusiastic language. Here is a man who really does love his numbers.

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Annabel is one of the Shiny editors and prefers this applied maths and statistics approach to algebra, trig and calculus any day!

Vaclav Smil, Numbers Don’t Lie (Penguin Viking, 2020). 978-0241454411, 382pp. incl index, hardback.

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