How bad are bananas?

Mike Berners-Lee: How bad are bananas? – The carbon footprint of everything. Profile Books, 2010, 240 pages, £8.99, ISBN 978 1 84668 8911.

If you want to reduce our carbon footprint this book is a useful handbook. It shows the carbon footprint of 80 items most of use – from sending a text message to having a child. It starts off with a guide to carbon and carbon footprints, how it is impossible to make an exact, scientific measure because there are so many variables. However, it is possible to calculate an estimate within a rather narrow range of possibilities.

With some of the examples there are more than one carbon footprint for an item depending on how it has been produced. To take the example of an apple: Zero CO2e for an apple plucked from your garden, 10 g CO2e if it is a local and seasonal apple, 80 g CO2e for an average apple (or 550g per kilo) and 150 g CO2e if the apple is shipped, cold stored and inefficiently produced.

So how bad are bananas? Answer: 80 g CO2e for one banana. A raw 4-ounce beefsteak has a carbon footprint of 2 kg CO2e – or the same impact as 25 bananas imported from another continent. Cheese has the same carbon footprint as meat – so being vegetarian might not be enough to get your annual carbon footprint down to the 2-3 tonnes that is the maximum if we want to avoid catastrophic climate change.

Although the book is mainly about food it does have calculations of the carbon footprint for other items as well, like a volcano, the world cup, the world's data centres, a bushfire, a country, a war and the burning the world's fossil fuel reserves.

It is not a book that tells you what to do but it allows you to make informed choices about what you want to do if you want to reduce your personal carbon footprint. It acknowledges that there are limits to what we can do as individuals unless we also change the way our society in the developed world is organised – in other words: it is the economy, stupid!