Isabel offsets her travel through https://www.cooleffect.org/. It makes it easy to calculate the carbon footprint of a trip, and it is cheaper than you would think to make a contribution to one of several good projects that can make a difference. More than anything, it keeps you aware of your impact. If you choose to try it, let your colleagues know (e.g., put a note on your title slide, “carbon offsets for this trip contributed through…”