We don’t know more about our climate than we do know. I just read a paper about the Arctic in the Proceedings of the National Academy of Sciences that says that basically the albedo feedback and an ice free summer in the Arctic could and eventually will lead to an ice free winter too. The implications for climate are immense. The Arctic is part of the Earth’s refrigeration system. The ice up there has been there for 14 million years without a break. See here
Apparently, the ice covered Arctic Ocean is stable and a seasonally ice covered Artic Ocean is not stable. We are transitioning to this seasonably covered state now. It may be just a few years or a few decades, but it is close at hand, and it is happening 50 to 70 years ahead of schedule.
Next, the authors do not know when, but they do understand that the change from a seasonally ice covered Arctic Ocean to a completely ice free Arctic Ocean, summer and winter, will occur rapidly, unexpectedly and irreversibly at some point. It’s called a bifurcation response, or tipping point or threshold.
Because ice reflects 93 percent of the sun’s energy harmlessly back to space and open water absorbs 90 percent of the sun’s energy and turns it into heat that hangs around, the warming differential is huge. More water means a lot more warming, which melts more ice, etc. Finally, at the bifurcation point, the water gets so warm that ice will not form in winter.
This is all part of the polar amplification effect that we see happening today. The new discovery is that a winter ice free condition will happen abruptly and unexpectedly. And if this occurrence is like most any other climate change related event in the last decade, it will happen much sooner than expected.
Eisenman and Wettlaufer, Nonlinear threshold behavior during the loss of Arctic sea ice, PNAS, January 2009.