And today, I'm once again chalking up the carbon debt, heading back to London for the next part of the Open University engagement.

I normally fly British Airways, but I've been annoyed enough at their service (especially with regards to using accumulated FF miles for upgrades) that I decided to try Virgin. Gotta make sure that Sir Richard has the $25 million he needs for his geoengineering challenge, you know.

Unless absolutely necessary, I don't fly United -- not since the engine caught fire on a flight to Philadelphia, while still on the tarmac, and because we were already late the crew didn't respond until quite literally the whole passenger cabin was yelling. Fool me once, shame on, shame on you, fool me -- can't get fooled again. Or something like that.