Add in the fact that the average thickness, as measured by submarines, has dropped by 40% since the eighties, and it's thought that the current summer ice volume stands at just 30% of what it was back then.
It's a worrying situation. The less Arctic ice there is, the faster existing ice melts as the Arctic Sea is warmed up. Which, in turn, accelerates global warming, because the Arctic is increasingly absorbing heat during the summer (via the darker water) rather than reflecting it back into space (via the ice).
The rising polar temperatures are also threatening to release huge quantities of methane (a powerful greenhouse gas) currently locked up in permafrost, which could further reduce ice extent in the future by adding to climate change. Some scientists warn that we may have an ice free Arctic during the summer before 2020.
In a few decades time we may be looking back on all this and saying this was a tipping point that marked the beginning of the end for the world's climate.
More here.
Update: The melt continued all the way up to the middle of September. In the end, the minimum extent was 50% below the 1979-2000 average. Ice core evidence suggests the current melt is unprecedented in the last 1500 years. Many scientists believe it has no precedent since the last Ice Age.
Welcome to the future.
