"This week in China, a Russian tanker ship will deliver a cargo of natural gas after taking the Arctic route across the top of the world and completing its voyage at the earliest time of year ever," reports Marketplace.

... "To be sure, it is becoming easier to cross the Arctic, given how quickly the ice is melting, said Donald Perovich, engineering professor at Dartmouth College’s Thayer School of Engineering. Perovich studies the geophysics of sea ice.

"'It’s highly reflective,” Perovich said. 'And when you lose this highly reflective sea ice and replace it by the dark ocean that absorbs more sunlight, you can get a positive feedback loop.'

"Sea ice reflects the sunlight back into space, so losing it is what Perovich calls a climate change 'amplifier.'

"Three decades ago, Perovich said, no one considered steaming a ship across the Arctic. 'And 30 years from now, if trends continue, it’ll be straightforward.'”