When I think about the lessons of carbon footprint calculations, I’m reminded of a quote by Mark Twain: “Numbers don’t lie, but liars do.” In my experience, this is a bit of a strong statement, but declaring the “bounds and scope” of greenhouse gas reporting allows us to avoid collecting data that is too “uncomfortable.” Uncomfortable perhaps because of what it might reveal, but more likely uncomfortable because of the personal energy it takes to collect the right data. This is a big challenge for carbon calculations. Event planners have to rely on their supply chain to provide specific information, and for some, this is too difficult. Then it is appropriate to declare something “out of bounds.” It is not a lie, especially if the organization is transparent about how the boundaries and scope were decided. Without transparency, we are approaching lying, or to use the politically correct term… “greenwashing.” In this case, transparency mitigates risk. Transparency with a plan for continuous improvement is commendable. (Reduce2.com,Glenn Hansen)