. >> reporter: jason gully, a glaciologist toe universi glaciologist at the university of south floridaecently enlisted gadd's help. >> we got winds around 50 miles per hour, temperatures dropping below zero. and we drop in to what happened to be one of the cool eaest cavs i've ever entered. >> i've never been in anyplace like this ever. >> me either. this is next level for sure. >> reporter: gadd took s noose scientists into a plunging cave, giving them unprecedented access. >> there's tremendous research going on in greenland. if the greenland iets sheet were to melt, it would raise sea levels five to seven meters. >> reporter: and that damage can be costly. a study released just this week warns that the melting arctic could cost the global economy nearly $70 trillion. gadd's team had hoped to the frigid waters beloet ice sheet, but here science comes with risk. >> that was exciting. >> i was afraid. there is so much debris and so much power in there, it was not a safe place to be. and this research is important. but it's not worth dying for. right there. you guys see this crack here?