A "radical shift" is plunging the Arctic Ocean towards an ice-free state for the first time in millions of years. One of the world's foremost ice experts, Professor Peter Wadhams of Cambridge University, calls it a "global disaster" that will cause such a big boost in global temperatures that even such extreme measures as geo-engineering need to be considered urgently.

Climate science has long understood that disappearance of summer sea ice in the Arctic would be a "tipping point" in the Earth's climate system, accelerating global temperatures and causing extreme weather and other climate changes far beyond the Arctic. Yet nearly every expert has been shocked by just how rapidly this "continent of ice" has been vanishing, and how dramatic the impacts have been already.

Climate scientists and ice experts are now using phrases like "unprecedented", "amazing", "extreme", "hard to exaggerate", "incredibly fast", "death spiral" and "heading for oblivion".

Arctic sea ice has been a permanent, year-round fixture of our planet since long before Homo sapiens first appeared on the savannas of Africa as a new species. Despite being robust enough to survive every change Mother Nature threw at it for millions of years, Arctic sea ice has proven to be shockingly vulnerable to a few decades of humanity's unrestrained fossil fuel pollution.

The trillion tonnes of CO2 pollution that people have released into the atmosphere from burning oil, coal and natural gas has acted like a blow torch on Arctic ice. A dozen pounds of Arctic sea ice has disappeared for every one pound of CO2 we have released. This highlights the incredible heating power of CO2 which pumps 100,000 times more energy into our climate than was given off when the oil, coal or natural gas was burned.

CO2 has been the "Energizer Bunny" of extreme weather, pumping energy into our climate non-stop for centuries.

As my the chart above shows, three-quarters of the "permanent", year-round sea ice in the Arctic has been cooked away in just 30 years. Over half of it has disappeared in just the last eight years. A vast expanse of ice larger than the European Union has vanished. What's left is half the area and only half as thick.

Now some ice experts are saying what remains could be gone in as little as ten years -- or even four.

Worse than worst case

This jaw-dropping acceleration of Arctic sea ice collapse is completely out-stripping the worst case scenarios of the UN International Panel on Climate Change (IPCC). The IPCC reports are the primary source of climate science used by world leaders, policy makers, businesses and citizens to decide the urgency and level of action needed.

The most recent IPCC report includes this graphic on the right. It predicts summer sea ice surviving long after most people alive today will have died of old age.

It is easier for decision makers to procrastinate on a difficult task if they don't think it will become critical for generations.