It seems common knowledge that riding your bike to work is a low carbon activity. What you might not know if that if you fuel your bike ride with air-freighted off season asparagus, then your carbon footprint increases dramatically and you'd be better off commuting buy Hummer. The art and science of taking into account many aspects of what constitutes a carbon footprint has often been ignored.
Mike Berners-Lee minutely examines and calculates the carbon footprint (by weight) of many activities and items in his new book, How Bad are Bananas?: The Carbon Footprint of Everything .
It all started with bananas. I was initially intrigued by bananas after reading Barbara Kingsolver's Animal, Vegetable, Miracle  several years ago, during which she and her daughter have a conversation with her daughter's friend about how bad bananas are because they are grown so far away and the energy used to transport them is bad for the environment. Continually intrigued by micro-histories, especially food related micro-histories, I eventually read Banana: The Fate of the Fruit that Changed the World  by Koeppel several years ago which changed my one-a-day banana habit from regular to organic, mainly due to the environmental conditions within the banana-growing countries. But still nagging me was the transportation costs on the environment; should I switch my breakfast mainstay to something more local? Berners-Lee calculates that actually bananas aren't really that bad. They are generally shipped by boat (MUCH lower carbon footprint than airfreight) and keep well without refrigeration.
In addition to bananas, Berners-Lee examines many other things and breaks down the environmental cost of things like paper vs. plastic, bus rides, drinking coffee, diapers, dairy products, laundry, asparagus, beer and wine, sending emails and riding in trains. The book is broken up into very small entries for each subject and is easy to read and often funny. This book doesn't answer every question about carbon footprints, but hopefully gives a new framework for measuring overall environmental impact of many everyday things - and explained in an easy to read manner.
Bonus! From the cover:
"I can't remember the last time I read a book that was more fascinating and useful and enjoyable."--Bill Bryson