Are things really measureable?

One method of measurement is called the carbon footprint. The carbon footprint is defined on Wikipedia as:
A carbon footprint is "the total set of greenhouse gas (GHG) emissions caused directly and indirectly by an individual, organization, event or product." For simplicity of reporting, it is often expressed in terms of the amount of carbon dioxide, or its equivalent of other GHGs, emitted.
The concept and name of the carbon footprint originates from the ecological footprint discussion.[2] The carbon footprint is a subset of the ecological footprint and of the more comprehensive Life Cycle Assessment (LCA).
http://en.wikipedia.org/wiki/Carbon_footprint

Currently the carbon footprint measurement method is the most widely known method. It is the basis for the United Nations Forum for Climate Control and the efforts of the Kyoto Protocol. Individuals can also measure their carbon footprint using many online tools. (e.g. http://www.begreennow.com/reduce-offset/carbon-calculator/)