The Science of Sea Ice
One of the incessant Global Warming Alarmist mantras is that the world is going to end because of decreasing ice at the North Pole. Unfortunately this WONDERFUL warming, which opens shipping lanes, massively increases the amount of arable land, and increases the biodiversity of the far north normally inhospitable to most species, may be short lived.
The chaotic extent of arctic sea ice has always been controlled by meandering sea currents and not changes in air temperatures. Rather than signaling any net global warming, it is rather that normally southern ocean currents have changed direction and very slightly. And it mimics a highly variable but similar pattern as that experienced in the early 20th century .
In fact, recent temperatures at both poles have been DECREASING in dramatic contrast to all climate models which predict exactly the opposite  especially in the face of rising CO2.
The failure of Global Warming Alarmist models, which predict an amplified warming of both poles, neither of which is currently true, is especially evident in the south. Unambiguously, for the last many decades, the southern Antarctic has been experiencing lower temperatures and growing ice sheets which have NEVER been colder or bigger in extent for as long as we have been measuring them.
EFFECTS ON POLAR BEARS
The polar bear population over the last million years has survived many cycles of increasing and decreasing ice coverage some of much greater magnitude than that currently experienced. Since 1950, when hunting was banned, the polar bear population has increased from 5,000 to nearly 30,000 in today’s warmer more hospitable world. 
CONSEQUENCES OF LESS ICE
Changes in the extent of arctic ice have no significant influence on sea level. This is because, according to Archimedes' principle, a floating ice berg displaces an equivalent mass of water independent of its volume; and the original mass of frozen water does not change as it melts. There is however a second order effect in that fresh water ice bergs reject heavier salt to the sea as they form. Thus the ocean becomes slightly more salty and dense in the winter and slightly less salty and dense in the summer when the ice bergs melt. The result should be a very small seasonal oscillation in ocean density and depth but which calculations indicate are currently below detectable limits.
Also, ice sheets at the poles have little effect on global temperatures because the sun’s angle of incidence is so low. In fact a total melting of all the ice at both poles would only change the total reflectance of the earth by less than some 5%. This is so much less than average changes in cloud cover, and consequent average albedo, that the arctic is often omitted entirely from climate models.
Nevertheless, without much conscious thought, global warming alarmists note that less ice reflects less sunlight back into space causing the darker exposed sea surface to absorb more sunlight and get warmer. By itself this has almost no effect whatever on net global temperatures but the claim is that this results in a massive [not observed] POSITIVE feedback which is entirely unchecked by any significant retarding negative feedback. Care must be taken because such models normally predict [no kidding] that the earth will catch fire and melt.
Unfortunately for alarmist predictions, ACTUAL observations of the real world indicate [and necessarily from simple theoretical considerations] that the feedback from the ice-albedo effect is not positive but is rather NEGATIVE .
This is because a decrease in ice cover means more sea water is evaporated causing an increase in cloudiness across the entire globe. This significantly REDUCES the global temperature. Basically cloud tops INCREASE the albedo as the original ice sheet melts and thus, as we OBSERVE, increase the amount of sunlight reflected back into space COOLING the planet .
WHAT IS A DEMAGOGUE?
On Dec. 10, 2007 former Vice-President Al Gore gave his famous “Earth Has a Fever” speech to the Nobel Prize Committee. In dire tones he proclaimed that all the Arctic sea ice across the entire top of the world could COMPLTETELY DISAPPEAR by the summer or 2013 due to global warming caused by carbon emissions. The exact quote  was
“… Scientists [have] reported with unprecedented alarm that the North Polar icecap is, in their words, 'falling off a cliff.' One study estimates that it could be completely gone during summer in less than 22 years. Another new study to be presented by U.S. Navy researchers later this week warns that it could happen in as little as seven years, SEVEN years from now."
In order to save civilization, Al Gore then parlayed the hysteria and Nobel Prize prestige into a tidy fortune of $100 MILLION dollars for himself personally in trading Carbon Cap and Trade credits . Fortunately all this worked because in 2013, the Arctic sea ice extent was bigger than any time since 2006. That was a close one and civilization was saved. Thank you Al…
Please note that all the alarmist climate models, which have all failed in every single prediction of absolute global temperatures, also fail to predict the change in ocean currents, fail to predict the temperature decrease at BOTH poles, and especially fail to predict the increased sea ice at the south pole. In fairness, they do predict less ice at the North Pole, but as the result of higher temperatures WHICH IS NOT OBSERVED. So perhaps the annual sum of $22 billion dollars spent on computer models to various “friends” of democrat environmental groups has not been entirely wasted.
In real science, but perhaps not in DS (democrat-superstition), models which consistently FAIL to predict temperature and sea ice extent are generally considered to be WRONG. Perhaps we might, just maybe might, start to consider how many acres of wilderness habitat [which is the real pressure on endangered species] we might save annually with 22 billion dollars rather than spending it on more DS.
1. Igor V. Polyakov, Genrikh V. Alekseev, Roman V. Bekryaev, Uma Bhatt, Roger L. Colony, Mark A. Johnson, Valerii P. Karklin, Alexander P. Makshtas, David Walsh, and Alexander V. Yulin, “Observationally based assessment of polar amplification of global warming”, Geophysical Research Letters, Volume 29, Issue 18, 24 September 2002, pages 25-1-25-4, .
4. Seiji Kato et al. in technical report at Langley Center of NASA published in 2006 http://www.sjsu.edu/faculty/watkins/cloudiness.htm
5. Kato, S., N. G. Loeb, P. Minnis, J. A. Francis, T. P. Charlock, D. A. Rutan, E. E. Clothiaux, S. Sun-Mack (2006), “Seasonal and Interannual Variations of Top-of-Atmosphere Irradiance and Cloud Cover over Polar Regions Derived from the CERES Data Set”, Geophysical Research Letters, 33, L19804, doi:10.1029/2006GL026685.