With LBS (location based services) becoming more effective and pervasive on cell phones, a London-based start up recently launched a new mobile application, called Carbon Diem that uses GPS to calculate your carbon footprint. Using GPS tracking to gage your speed, the software determines whether you are walking, driving or flying and uses this information along with miles covered to figure out your environmental impact. The developer's algorithm relies on your speed and pattern of movement to identify your mode of transportation so the user never has to enter information. Perfect for lazy environmentalists.

The UK's Guardian reported that it was about 70% accurate on buses and in cars according to their own tests with Nokia and Blackberry phones, but other sources claim 100% accuracy when traveling by plane.