The calculation method used by Shrink tries to capture the full life cycle of all aspects of our personal consumption. We focus on consumption in each of our five major categories: housing, travel, food, products and services. In addition to these we also estimate the share of national emissions over which we have little control, government purchases and capital investment.
Read more at http://shrinkthatfootprint.com/calculate-your-carbon-footprint#FTvp05oM57c53X8l.99