Just this past week, Simon wrote a commentary on this in the Wall
Street Journal. Ehrlich and company lost the first bet and paid up.
As for the second bet, Simon said they could pick any measure(s) of
growth they liked and he would bet that over a period of ten years or
more the measure would increase.
I'm not sure I remember all the details, but apparently Ehrlich wanted
to use something like the amount of ozone in the atmosphere as a
measure of progress and Simon said, no, it would have to be some
measure of economic growth. So now, according to Simon, Ehrlich is
running around saying that Simon will no longer risk betting on
progress in the future.