How Bad are Bananas? by Mike Berners-Lee Profile Books HK$135

If you already use online carbon calculator websites to work out your carbon footprint, you don't need to buy this book. As Mike Berners-Lee writes, the aim of How Bad are Bananas? is to give readers a 'carbon instinct' rather than to provide exact numbers for wonks to gauge how green their way of life is. He acknowledges his assumptions and maths may be debatable, thus producing 'flaky' numbers, but argues that going through the thought process can be useful in itself. That said, his choice of entries for which he gives the carbon dioxide equivalent (the convention for expressing carbon footprints) are well thought out. Readers (in developed countries anyway) should find many relevant examples of everyday products and services. These include everything from text messages (0.014g CO2e per message) to milk ('high-carbon stuff for the same reasons beef is') to bananas (at 80g CO2e each 'they're not bad at all'). He compares using paper towels with electric hand driers (10g CO2e versus 20g CO2e), while a typical return flight from Hong Kong to London burns up 4.6 tonnes CO2e.