Original sources:
The earlier USGS study, summarized on a poster here:
https://csc.alaska.edu/sites/default/files/Waldrop_NACP_AGU2012.pdf
The original paper for the new study is online here:
http://www.pnas.org/content/early/2017/05/02/1618567114
And the detailed appendix is here:
http://www.pnas.org/content/suppl/2017/05/03/1618567114.DCSupplemental/pnas.1618567114.sapp.pdf
