Yikes - according to Carbon Zero, for Adam and I to fly to Calgary and back will create 1.65 tonnes of CO2. Gah! Instead of buying offsets, I used Carbon Zero's calculator to find out how much the offsets would have cost (just under $40) and I'm going to donate that much to the Ecology Action Centre for their ongoing work to create a more sustainable (or, as Sharon at Casaubon's Book prefers to say, "regenerative") society.