snydeq writes "Sustainable IT's Ted Samson raises questions regarding the purchasing of carbon offsets, a practice growing in popularity among tech companies such as Dell, Yahoo, and Google in an attempt to achieve 'carbon neutrality.' Essentially financial instruments, carbon offsets enable companies to invest money in sustainable endeavors in an attempt to counteract the carbon footprint they incur conducting their business. But as a recent article in the Wall Street Journal shows, measuring the value of these carbon offsets is tricky business, as some recipients of offsets say the results of their sustainable efforts would be achieved regardless of any one company's investment. 'The question of whether carbon offsets hold value just scratches the surface of the overall carbon-neutrality question,' Samson writes. 'For the time being, there isn't even a consistent approach to measuring an organization's carbon footprint in the first place. And if you don't know how much CO2 you're responsible for, how do you know how much offsetting is necessary to become neutral?'"