“The Last Time the Arctic Was Ice-Free in the Summer, Modern Humans Didn’t Exist”
http://www.slate.com/blogs/future_tense/2014/12/02/the_last_time_there_was_this_little_arctic_ice_modern_humans_didn_t_exist.html
“The Last Time the Arctic Was Ice-Free in the Summer, Modern Humans Didn’t Exist”
http://www.slate.com/blogs/future_tense/2014/12/02/the_last_time_there_was_this_little_arctic_ice_modern_humans_didn_t_exist.html