Spending six months of every year in the Arctic, adventurer Tetsuhide Yamazaki sees the impact of global warming firsthand through the region's thinning sea ice, the expanse of which has roughly halved in the last three decades.

The ice is "very thin this year," Yamazaki, 45, said after confirming a thickness of 118 cm with a drill during his recent exploration of an area at the North Pole. Sea ice in the area is usually almost 2 meters thick, according to Yamazaki, who senses the ice grows thinner every year.

Born in October 1967 in Hyogo Prefecture and raised in a coastal town in Fukui Prefecture, Yamazaki decided to become an explorer when he was in high school in Kyoto after reading a book by well-known adventurer Naomi Uemura, who climbed Mount McKinley solo in 1970. The explorer was lost on the mountain in February 1984.