The ability to identify GHG levels throughout the supply chain is one of the reasons many organizations set out to measure their footprint in the first place--they've been told they have to do it or lose their place to a supplier who can and will perform carbon inventories.

Ekaterina

I agree that to be sustainable, a company must look backwards and forwards in their value chain, but GHG reduction can't be the only focus of a company's sustainability effort. Sustainability is a strategy, and for it to be successful issues such as resource use and social implications need to be assessed. For example: is it better to use traditional light bulbs even though they use more energy, or is it better to use CFLs even though they contain mercury? Looking at issues from a holistic perspective will make you raise these questions and come up with a better solution. The "greatest impact" method used above addresses a significant element of the issue, but needs to be applied in a way that accounts for all aspects of sustainability.

Thanks for pointing out that companies (and people) need to look at these issues in a holistic way. We focused the article on greenhouse gas emissions because they are a good place for companies to start looking upstream and down, but certainly aren’t suggesting that GHGs should be the only focus of sustainability efforts.

-Marshall