From Gavin, who was being a bit cheeky. Or perhaps given the location, had passed a tippling point.
For those who don’t get the joke, the letters M, B, and H should ring a bell.
On a side note, the balding with goatee/beard to clean shaven ratio at AGU 2013 wasn’t nearly as high as I expected it to be. I’d say about 1-10. It seems to be a trait of Real Climate scientists, tectonic and geology guys, not so much.