> oldest [...] [is] about [residence time] Only if the reservoir is a fifo queue. :) Otherwise there's a distribution, with a tail. But oldest in atmosphere

> oldest [...] [is] about [residence time] Only if the reservoir is a fifo queue. :) Otherwise there's a distribution, with a tail. But oldest in atmosphere still looks (envelope scribbling...) order Myr? Rather than Gyr. Similar for breath?