Arctic "death spiral" leaves climate scientists shocked and worried
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.
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.
And sure enough, humanity has procrastinated badly in tackling the climate threat. The amount of fossil fuel CO2 pollution the world is pumping out every year is still increasing, even as extreme weather and climate shifts are accelerating.
The IPCC predictions come from a suite of the best global climate models at the time. Below is a chart showing the predictions of the IPCC global models used in their most recent report. For comparison I've added a bold orange line showing the best estimates -- based on multiple modes of observations -- for what has actually happened.
These IPCC models are off by many decades -- whole generations, in fact. New models are being developed for the next IPCC report. They have been described as "less bad" in some ways but they still fail to offer any better guidance than the old models on how quickly summer ice will vanish. At this rate the ice will be gone before we can we can build models to tell us that.
The orange "best estimate" values on the chart come from a University of Washington project called PIOMAS. For years many experts were sceptical of PIOMAS ice loss estimates because they were so extreme and because humans didn't have complete high quality data for ice volume. Could they be wildly wrong?
Unfortunately, the answer is no. Two years ago, the European Space Agency launched a satellite (CryoSat-2) specifically designed to very accurately measure sea ice volume. The results from the first two years have confirmed the PIOMAS estimates. Three quarters of the summer ice volume really seems to have vanished.
A recent CBC report on these CryoSat-2 results was blunt: "Arctic ice could vanish in 10 years, scientists warn … Arctic sea ice is melting at a pace so much faster than once thought that the latest projections say it might disappear by as soon as 2022."
Professor Wadhams, whose predictions of rapid ice loss have so far been among the most accurate, told the Guardian he thinks summer Arctic sea ice could vanish within four years.
Once again we are being caught off guard as the actual pace of climate change is unfolding far more rapid than the conservative IPCC estimates used by policy makers, businesses and citizens worldwide. These conservative estimates have encouraged a tepid policy response. Further encouraging foot-dragging on climate action has been a well-organized, well-funded campaign of fake climate skeptics attacking the science and scientists that sought to alert humanity to the need to act more quickly.
Just how badly have we dithered in removing climate pollution -- and the economic risk that goes with it -- from the global economy? Take a look:
The chart above shows the ever increasing amount of fossil fuel CO2 that humans are releasing each year. Not only are we pouring lots more fuel into global warming each year, we are also doing it at a rate that was considered a worst case scenario by the IPCC just a decade ago.
Clearly we have persuaded ourselves that climate damages would unfold slowly over a century or more. But now in the Arctic we have again drawn the short straw.
All that vanishing sea ice is amplifying global warming and extreme weather far beyond the Arctic. A series of global warming feedback loops --- outside of our direct control -- are emerging already. As one climate scientist put it: "What happens in the Arctic doesn’t stay in the Arctic."
As the meltdown continues the impacts are expected to get worse.
Here is a quick overview of some of the big, currently known, impacts...