Comment on “Catastrophic ice shelf breakup as the source of Heinrich event icebergs” by C. L. Hulbe et al.

] Hulbe et al. [2004] argue that the original binge-purge model of their coauthor MacAyeal [1993a, 1993b]is not appropriate for Heinrich events but that a new ice-shelf-collapse mechanism may work. We believe that thenew collapse mechanism disagrees with important dataand that MacAyeal’s original model remains viable afterappropriate modifications. We have enjoyed a fascinatingdiscussion with Hulbe et al. on this topic, which isstimulating our thinking and research, and we presentsome of the arguments here for a wider audience.[