The monster Arctic storms like we've seen this year have sped up the rate of sea ice loss, but increased water temperatures and air temperatures due to human-caused global warming are the dominant reasons for the record melting of the Arctic sea ice. A July 2012 study by Day et al. found that the most influential of the possible natural influences on sea ice loss was the Atlantic Multi-decadal Oscillation (AMO). The AMO has two phases, negative (cold) and positive (warm), which impact Arctic sea ice. The negative phase tends to create sea surface temperatures in the far north Atlantic that are colder than average. In this study, the AMO only accounted for 5% - 31% of the observed September sea ice decline since 1979. The scientists concluded that given the lack of evidence that natural forces were controlling sea ice fluctuations, the majority of sea ice decline we've seen during the 1953 - 2010 period was due to human causes.

It is difficult to overstate the magnitude of what is now unfolding in the Arctic region. The Arctic ice cap used to cover 2 per cent of the Earth’s surface, and the ice albedo effect meant vast amounts of solar energy were bounced back into space from the bright white ice mass.Losing this ice, and replacing it with dark open ocean, creates a dramatic tipping point in planetary energy balance.“The extra radiation that’s absorbed is, from our calculations, the equivalent of about 20 years of additional CO2 being added by man,” Prof Wadhams said.With global carbon dioxide (CO2) emissions already spiralling far beyond the levels that scientists have warned present grave risks to humanity, the injection of a massive new source of additional energy into Earth systems could hardly have come at a worse time.

On the other end of the spectrum are those who think the melt could happen much sooner.  Peter Wadhams, who leads the Polar Ocean Physics Group at the University of Cambridge, has predicted since 2008 that the Arctic ice could be gone in summer by 2015.  He now believes there’s a chance that it could happen even sooner. Similarly, Mark Drinkwater, the European Space Agency’s senior advisor on polar regions and a mission scientist for the CryoStat satellite that measures arctic ice, believes that the Arctic could be ice free in September by the end of this decade.

Arctic sea ice is an important component of the global climate system. The polar ice caps help to regulate global temperature by reflecting sunlight back into space. White snow and ice at the poles reflects sunlight, but dark ocean absorbs it. Replacing bright sea ice with dark ocean is a recipe for more and faster global warming. The Autumn air temperature over the Arctic has increased by 4 - 6°F in the past decade, and we could already be seeing the impacts of this warming in the mid-latitudes, by an increase in extreme weather events. Another non-trivial impact of the absence of sea ice is increased melting in Greenland. We already saw an unprecedented melting event in Greenland this year, and as warming continues, the likelihood of these events increase.

The Arctic sea ice, essentially, it is a big reflector of solar energy during the summer, and that keeps the Arctic cooler than it normally would be. It acts like an air conditioner in a sense for the Earth's climate system. And that helps not only keep the Arctic cooler, but also the globe as well. And it's basically a sink for heat that comes in at the equator, gets transported to the north. And then you lose the heat in the Arctic. And those -- that transfer of heat from the equator to the poles, that essentially helps set up things like the jet stream, our prevailing winds, our weather tracks. And so as we start to lose the ice cover and we warm up the Arctic, essentially, that's changing the balance between the equator and the poles. And that will shift things like storm tracks and the jet stream, and that will change weather patterns.

The depleting ice cover would have serious ramifications for the planet. Arctic ice acts as a reflector of sunlight, helping regulate Earth's temperature, cooling the climate. "When there's no longer that sea ice below the air mass and it's just open ocean, that's when more moisture off the ocean's surface gets into the atmosphere and the water vapor in the atmosphere makes for more violent storms," says Yackel. "We can also expect to see an increase in storm frequency and storm intensity for most of the world's populated places as the Arctic and Earth continues to warm."

"This collapse, I predicted would occur in 2015-16 at which time the summer Arctic (August to September) would become ice-free. The final collapse towards that state is now happening and will probably be complete by those dates".Wadhams says the implications are "terrible". "The positives are increased possibility of Arctic transport, increased access to Arctic offshore oil and gas resources. The main negative is an acceleration of global warming.""As the sea ice retreats in summer the ocean warms up (to 7C in 2011) and this warms the seabed too. The continental shelves of the Arctic are composed of offshore permafrost, frozen sediment left over from the last ice age. As the water warms the permafrost melts and releases huge quantities of trapped methane, a very powerful greenhouse gas so this will give a big boost to global warming."

You might not think that what happens in the Artic has much bearing on what happens in Texas or Moscow or southern provinces of China, but a study published in 2012 in Geophysical Research Letters has drawn a convincing connection. Blowing around the periphery of the Arctic is the polar jet stream – a region of high speed wind that blows west to east, and helps drive wind circulation around much of the northern hemisphere.  The jet stream is powered by the temperature difference in fall and winter between the Arctic and the more temperate areas just to its south. But as the Arctic ice has receded, the Arctic Ocean waters have absorbed more heat in late summer and early fall.  In late fall and early winter, they’ve given that heat up, back into the atmosphere. That, in turn, has led to warmer Arctic autumns and winters, which has reduced the temperature difference that fuels the jet stream. The result is that the jet stream is now weaker than it once was – about 14% weaker than it was in 1980. Why does this matter? Because a slower jet stream makes it easier for ‘blocking’ weather patterns to develop.  Blocking weather patterns are the ones that hover over a region rather than moving on – like the drought that basted Texas in 2011 and decimated its forests and hay and wheat crops to the tune of more than $7 billion in damage, and like the heat wave that enveloped Moscow and much of the rest of Russia for most of the summer of 2010, killing an estimated 55,000 people in July and August of that year.

"In the context of what has happened in recent years, this indicates that the ice cover in the Arctic is changing fundamentally," said Walt Meier, a scientist at the NSDIC commenting on the August data. While in 2007, the summer weather was very favorable to the melting ice, in 2012, it is the delicacy of the ice cover that has contributed to the record retreat of Arctic sea ice. "The previous record, set in 2007, occurred because of near perfect summer weather for melting ice. Apart from one big storm in early August, weather patterns this year were unremarkable. The ice is so thin and weak now, it doesn't matter how the winds blow." said Mark Serreze, director of the NSDIC in a report on the NSDIC website.

If the Arctic sea ice loses volume at the same rate that it has over the last 12 years, then the first ice-free Arctic day in September could happen in the next 5 years. If the rate of ice volume loss continues to accelerate, as it has been, then that day could be even sooner.

Every major scientific institution that tracks Arctic sea ice agrees that new records for low ice area, extent, and volume have been set. These organizations include the University of Washington Polar Science Center (a new record for low ice volume), the Nansen Environmental & Remote Sensing Center in Norway, and the University of Illinois Cryosphere Today. A comprehensive collection of sea ice graphs shows the full story.

But the long-term consequences of the ice loss are far more substantial and far more difficult to predict, says Masters. The reason? The jet stream, the fast-flowing river of air that helps to regulate temperatures and weather patterns across much of North America and parts of Europe.Many climate scientists believe the jet stream could change in major ways thanks to warming temperatures and shrinking ice in the Arctic. By moving cold and warm air around the earth, the jet stream helps even out its overall temperature. If the Arctic gets warmer, there’s no need for the jet stream to move as quickly as it does now.“If you’ve got more heat in the Arctic, the jet stream decreases in strength,” he added. “When the jet stream slows down, now that means that when you have an extreme period of weather, it tends to hang around longer.”

Besides the decline in sea ice extent, the ice cover has grown thinner and less resistant to summer melt. Recent data on the age of sea ice, which scientists use to estimate the thickness of the ice cover, shows that the youngest, thinnest ice, which has survived only one or two melt seasons, now makes up by far the largest part of the ice cover. This means that as each year passes, the ice cover melts faster than previous years.

As the Arctic summer ice pack is floating, its melt does not directly raise sea levels, but as it spirals towards final destruction, all bets are off as to the stability of the adjacent massive land-based Greenland ice pack. There is enough frozen water locked up here to raise global sea levels by six to seven metres over time.

Average temperatures in the Arctic region are rising twice as fast as they are elsewhere in the world. Arctic ice is getting thinner, melting and rupturing. For example, the largest single block of ice in the Arctic, the Ward Hunt Ice Shelf, had been around for 3,000 years before it started cracking in 2000. Within two years it had split all the way through and is now breaking into pieces.

Dr. Zhang explained that climate change has caused sea ice to retreat markedly in recent decades and has also warmed Arctic Ocean temperatures. Such changes may be providing more energy and moisture to support cyclone development and persistence. The strong storms of this week and a month ago would have had far less impact on the ice just a decade ago, when the sea ice was much thicker and more extensive.

One of the world's leading ice experts has predicted the final collapse of Arctic sea ice in summer months within four years.In what he calls a "global disaster" now unfolding in northern latitudes as the sea area that freezes and melts each year shrinks to its lowest extent ever recorded, Prof Peter Wadhams of Cambridge University calls for "urgent" consideration of new ideas to reduce global temperatures.

The shrinking of the ice cap was interpreted by environment groups as a signal of long-term global warming caused by man-made greenhouse gas emissions. A study published in July in the journal Environmental Research Letters, that compared model projections with observations, estimated that the radical decline in Arctic sea ice has been between 70-95% due to human activities.

Yet he also warned that it was becoming clear the impacts of climate change were worst than had been expected. Talking about the record Arctic sea ice melt this summer, he said: "The situation is worse than we thought [in the Arctic]. The processes of melting are more volatile than we thought. More complicated. The ice cap is really melting faster than we thought."

"Climate models have predicted a retreat of the Arctic sea ice; but the actual retreat has proven to be much more rapid than the predictions," said Claire Parkinson, a climate scientist at NASA Goddard Space Flight Center, Greenbelt, Md. "There continues to be considerable inter-annual variability in the sea ice cover, but the long-term retreat is quite apparent." The thickness of the ice cover is also in decline.

It is difficult to overstate the magnitude of what is currently unfolding in the Arctic regionTHE TRUTH, as Winston Churchill put it, is incontrovertible. “Malice may attack it, ignorance may deride it, but in the end, there it is.” Scrape away the layers of denial, obfuscation and spin that cloud climate change and one unvarnished truth emerges: the Arctic ice cap is dying – and, with it, humanity’s best hopes for a prosperous, predictable future.

Prof Peter Wadhams of the Polar Ocean Physics Group described the September 2012 figures as a “global disaster”. He now projects the destruction of Arctic summer sea ice by 2015-16 – more than half a century ahead of the IPCC’s projections. “The final collapse towards that state is now happening and will probably be complete by those dates,” he added.

But there might be a less dramatic reason than polar ice melting for the higher ocean level -- the higher temperature of the water. Water is most dense at 4 degrees Celsius. Above and below this temperature, the density of water decreases (the same weight of water occupies a bigger space). So as the overall temperature of the water increases it naturally expands a little bit making the oceans rise.In 1995 the Intergovernmental Panel on Climate Change issued a report which contained various projections of the sea level change by the year 2100. They estimate that the sea will rise 50 centimeters (20 inches) with the lowest estimates at 15 centimeters (6 inches) and the highest at 95 centimeters (37 inches). The rise will come from thermal expansion of the ocean and from melting glaciers and ice sheets. Twenty inches is no small amount -- it could have a big effect on coastal cities, especially during storms.

NSIDC scientist Ted Scambos said, "Antarctica's changes—in winter, in the sea ice—are due more to wind than to warmth, because the warming does not take much of the sea ice area above the freezing point during winter. Instead, the winds that blow around the continent, the "westerlies," have gotten stronger in response to a stubbornly cold continent, and the warming ocean and land to the north." Researchers believe that climate change has created a "wind wall" that keeps the cold around the South Pole while the rest of the globe is warming.

Ed Davey, the UK climate and energy secretary, said: "These findings highlight the urgency for the international community to act. We understand that Arctic sea-ice decline has accelerated over recent years as global warming continues to increase Arctic temperatures at a faster rate than the global average.

The second thing to fear about loss of Arctic sea ice is the potential to accelerate climate change on a global basis.

The radical decline in sea ice around the Arctic is at least 70% due to human-induced climate change, according to a new study, and may even be up to 95% down to humans – rather higher than scientists had previously thought.

The amount of greenhouse gases that are likely to be released from the Arctic melt this century is still uncertain. The UN report looked at a range of scenarios that would put between 43 billion and 135 billion tonnes of extra carbon dioxide from the Arctic into the air this century. ''Based on these ranges, you would have potentially anywhere between 3.8 per cent and 12.3 per cent more carbon being put into the atmosphere, on top of all the other sources that are emitted,'' said Pep Canadell, a CSIRO scientist and executive director of the Global Carbon Project, which tallies up CO2 emissions.

A warmer Arctic will also affect weather patterns and thus food production around the world. Wheat farming in Kansas, for example, would be profoundly affected by the loss of ice cover in the Arctic. According to a NASA Goddard Institute of Space Studies computer model, Kansas would be 4 degrees warmer in the winter without Arctic ice, which normally creates cold air masses that frequently slide southward into the United States. Warmer winters are bad news for wheat farmers, who need freezing temperatures to grow winter wheat. And in summer, warmer days would rob Kansas soil of 10 percent of its moisture, drying out valuable cropland.

David Robinson, a climatologist with Rutgers University, said the record for melting sea ice was shattered in 2007. "We thought that might be the record for quite a while," he said. "And here we are, just five years later, and we've shattered that record. We're seeing losses of sea ice I never thought I'd see in my career."

"We are on the edge of one of the most significant moments in environmental history as sea ice heads towards a new record low. The loss of sea ice will be devastating, raising global temperatures that will impact on our ability to grow food and causing extreme weather around the world," said John Sauven, director of Greenpeace UK.

the complete meltdown of the Arctic could roughly double the rate of warming of the planet as a whole.

“We’re in uncharted territory,” says James Overland of the University of Washington. The weakening jet stream means “wild temperature swings and greater numbers of extreme events”. The last time the Arctic is believed to have been ice-free is during the Eemian period, about 125,000 years ago, when global sea levels were between four and six metres higher than today. However, current atmospheric CO2 levels are already far higher than during the Eemian; indeed, you would have to go back several million years to find any era in the Earth’s history to match today’s levels of this powerful heat-trapping “greenhouse gas”.Lags in the system mean that we have so far experienced only the very mildest of the effects of the ever-growing heat imbalance in our climate system.

One of the curious features of the latest set of data is that Antarctic sea ice has seen a record expansion. According to NSIDC the reasons for this are ‘complex and surprising’ but are inextricably linked to global climate change.

A UN report issued at climate change negotiations in Doha, Qatar, found that human greenhouse gas emissions were triggering the Arctic thaw.

What climate change does is make many "natural" events more frequent and worse. By continuing to pump millions of tons of carbon pollution into our atmosphere every single day, we are throwing Earth's complex climate system out of whack, and this is the price we pay. Science tells us that the destructiveness of this storm was fueled by climate change -- driving higher sea levels that pushed up storm surge, and higher ocean temperatures that contributed to the monstrous size of the storm and loaded extra rain into the clouds. Science has identified another powerful potential factor: The record-breaking melting of Arctic sea ice's impact on the jet stream may have created the block of high pressure above Greenland that drove Sandy west into the continental United States, rather than allowing it to spin off east into the North Atlantic, as most late-season hurricanes do.

One person’s global catastrophe is another’s commercial opportunity. Governments and energy companies, notably Shell, are busy jostling to be in position to loot the oil and minerals hidden beneath the region’s fast-disappearing ice. This is akin to setting your house on fire to keep yourself warm.

The sheet of ice that covers the North Pole melted to its smallest size on record in late August, shattering the previous record set just five years ago and providing a strong sign of the long-term warming of the earth's climate."This is happening before our very eyes," said Jennifer Francis, a research professor with the Institute of Marine and Coastal Sciences at Rutgers University. "It’s not something that’s happening decades from now or generations from now. It’s real and it’s now."

Climate change is driving more extreme weather – by heating up the atmosphere, pumping more energy into storms, and heating the air to the point that it can more easily suck away moisture or concentrate it in one point.  As the planet continues to warm, all of those factors will increase, leading to more heat waves, more droughts, and more floods. And the changes to the Arctic, it seems, will exacerbate this, by slowing down the jet stream, and making it more likely that the extreme weather conditions that develop get locked in place, hammering the same regions for protracted lengths of time.

THE massive release of methane and other gases from the Arctic will make it tougher to meet human greenhouse gas cuts, but the scale of the problem will still be determined by how much fossil fuel is burned by humans in coming decades, scientists say.

This ability to rapidly adapt to varying environmental conditions has made it possible for us to survive in most regions of the world.  We live successfully in humid tropical forests, harsh deserts, arctic wastelands, and even densely populated cities with considerable amounts of pollution.  Most other animal and plant species are restricted to one or relatively few environments by their more limited adaptability.

Over the last half million years at least, we invented technological aids that allowed us to occupy new environments without having to first evolve biological adaptations to them.  Houses, clothing, and fire permitted us to live in temperate and, ultimately, arctic regions despite the fact we still essentially have the bodies of tropical animals.

West Antarctica has warmed much more than scientists had thought over the last half century, new research suggests, an ominous finding given that the huge ice sheet there may be vulnerable to long-term collapse, with potentially drastic effects on sea levels.

If even 10% of the northern permafrost’s buried carbon were released as methane, it would have a heating effect over the next decade equivalent to ten times all human greenhouse emissions to date, and over the next century equivalent to roughly four times all human greenhouse emissions to date. And the permafrost is melting.  In Fairbanks, Alaska, ground that’s been frozen solid for 10,000 years is melting, opening up sink holes. In the town of Newtok, Alaska, the permafrost melt has been so bad that the residents recently voted to move the entire town rather than stay and watch it sink into the once frozen land.