Antarctic ice floes extended further than ever recorded this southern winter, confounding the world’s most-trusted climate models.
“It’s not expected,” says Professor John Turner, a climate expert at the British Antarctic Survey. “The world’s best 50 models were run and 95% of them have Antarctic sea ice decreasing over the past 30 years.”
There is a concept in statistics called a 95% confidence interval. That is, the researcher is confident that 95% of the time, his/her results reflect reality. Here, 95% of the "world's best models" fail to reflect reality. They have also failed to predict the current, 18-year, warming hiatus.
“In some ways it’s a bit counterintuitive for people trying to understand how global warming is affecting our polar regions, but in fact it’s actually completely in line with how climate scientists expect Antarctica and the Southern Ocean to respond.
If they had expected it, 95% their models would have reflected it, not 5%.
Particularly in respect to increased winds and increased melt water,” said Williams.
Currently, the effect of greenhouse gases is being overshadowed by other local climate phenomena, says Turner. “By far the biggest impact has been the ozone hole. The signal of increasing greenhouse gases is buried beneath all the other signals.”
The depletion of the ozone layer above Antarctica during last century by emissions of chlorofluorocarbons (CFCs) has caused an overall cooling trend on the continent.
Ozone itself is a greenhouse gas and its reduction has seen more heat reflecting back into space.
So, we have known about the ozone hole for decades, known that ozone was a greenhouse for over a century, and no one figured the ozone hole into the climate models?
The ozone hole is changing the climate of an entire continent and no one thought to take it into account? What other factors are being missed in the climate model? Especially those that might account for the current 18 year hiatus?
It is estimated that the Pine Island glacier alone loses so much water that it is responsible for 10% of global annual sea level rise (which is about 3mm per year). Warm currents come from deep water and heat the underside of the ice sheet, causing it to melt.
Warm currents? Warm currents float on the surface of colder, and denser, water. Even comparatively "warm" water would not sink in the first place. The deep ocean is about 4 degrees C because that is the temperature of water at its densest. So where would "warm" water be sinking?
Additionally, research has shown that the deep ocean is not warming. So if the deep ocean is not warming, where is the "warmth" coming from to melt the glacier?
Turner says this process probably has little to do with global warming. “Pine Island seems to be an ongoing retreat that could have been going on for 10,000 years,” he says.
But, in some future article, it will be blamed on global warming.