. We join the Arctic Sunrise as it moves slowly up Sermilik Fjord . This is simply the most beautiful place I 've ever seen . It 's an inky blue body of water thick with floating , ancient ice . Some of the icebergs are mountainous . They all come from the Greenland ice sheet , a vast mass of frozen fresh water , hundreds of miles across and up to two miles thick . View the gallery of the stunning landscape '' Over the next four days we observe independent scientists working to understand why the ice sheet is melting so rapidly . We fly over and land on Helheim Glacier , a major outlet for the ice sheet which has sped up dramatically in the last decade . We accompany oceanographers in inflatable boats as they collect data on the warming water currents in the fjord . All this research , they say , points to sea levels rising beyond current predictions . There are still those who question humankind 's role in the warming of the Earth 's climate , but these scientists are not among them . `` Things could be very bad , ''
-LRB- CNN -RRB- -- My taxi driver is telling me about his meal last night . His name is William . He ate whale . Melting world : mountainous icebergs in Greeland 's Sermilik Fjord . `` Delicious , '' he says , kissing the tips of his fingers on one hand , making the universal sign for good tasting food . William tells me he went out on a boat with some friends a few days ago and shot the whale . I 'm not sure how I feel about this . Welcome to Greenland . On this remote but enormous island subsistence whale hunting is allowed . This was just the memorable start to an extraordinary journey . Cameraman Neil Bennett and I had traveled to the small town of Tasiilaq in southeastern Greenland to meet up with the Arctic Sunrise , a ship belonging to the environmental group Greenpeace . Read Neil 's blog on filming in challenging conditions The 34-year-old icebreaker and its crew are on a three month expedition around Greenland 's coast . They say their mission is to help scientists working in the region and to publicize the environmental changes taking place here