See the blue line? That's this year. The dotted green? That's 5 years ago.
And from the journal Science (from the good folks at the American Association for the Advancement of Science) we can read a possible explanation:
A new enemy is undermining ice floating on the Arctic Ocean: heat from below.The journal Science, by the way, is peer-reviewed and one of the oldest and most prestigious science journals on the planet. It's also the journal that Representative Lamar Smith, chair of the House Committee on Science, called "not objective."
Sensors that have plumbed the depths of Arctic seas since 2002 have found warm currents creeping up from the Atlantic Ocean and helping drive the dramatic retreat of sea ice there over the last decade. A new study shows this “Atlantification” of the Arctic Ocean as a new, powerful driver of melting, alongside losses due to rising air temperatures.
And Donald Trump thinks it's a Chinese hoax designed to undermine American productivity.
So I suppose it's the Chinese who're pumping all that warm water into the Arctic?