The Vales calculate the carbon footprint of a medium-sized dog as 2.08 acres, more than twice the 1.01 acres needed to create enough energy to build a Toyota Land Cruiser. However, the pair said the average driver travels about 12,000 miles a year, making the carbon footprint of the Toyota and the dog roughly equivalent.
However, some experts cast doubt on the book's claims.
"Everything has an impact on the environment but I'm surprised by the size of these numbers. Without analyzing them further I find it difficult to believe," said John Buckey, managing director of carbonfootprint.com.