While some remain critical that global warming is occurring at all, the melting of the North Pole represents a sharp indicator against voices of doubt.  Now scientists are predicting that a major milestone will be reached this summer or next -- the disappearance of the North Pole's ice cover during the Arctic Summer.

To most, imagining the North Pole without ice -- only water -- is an incredible prospect.  But that's the reality of a warming world.

The prediction comes from the U.S.'s top climate researchers at the National Snow and Ice Data Center in Boulder, Colorado.  They predict that in September, there is a good chance that the ice will be gone on the pole. 

While this is obviously a rather sobering event, the scientists aren't afraid to poke a little fun at the climatological milestone.  Says the center's senior research scientist, Mark Serreze, "We kind of have an informal betting pool going around in our center and that betting pool is 'does the North Pole melt out this summer?'"

About half the researchers are betting that the geographic pole, currently covered in ice will be ice free this fall.  Last year already saw a similarly landmark event -- the Northwest Passage was ice free last September for the first time in recorded history.

All of these events are merely part of a larger trend according to researchers.  Says Serreze, "What we've seen through the past few decades is the Arctic sea ice cover is becoming thinner and thinner as the system warms up."

Why are they uncertain about whether this summer's warmth will pierce the polar ice?  The warming fluctuates largely with weather patterns, so the metaphorical straw that breaks the camel's back will likely be weather, either this year or next.

"Last year, we had sort of a perfect weather pattern to get rid of ice to open up that Northwest Passage,"  explains Serreze, "This year, a different pattern can set up. so maybe we'll preserve some ice there. We're in a wait-and-see mode right now. We'll see what happens."

While the event is significant, it will not cause any problems says Serreze.

He states, "From the viewpoint of the science, the North Pole is just another point in the globe, but it does have this symbolic meaning.  There's supposed to be ice at the North Pole. The fact that we may not have any by the end of this summer could be quite a symbolic change."

He does say that the rate of disappearance still "astounds" him, even though he's used to seeing unusual weather daily.  He says the development is just a sign of how global warming is picking up its pace.

Says Serreze, "Five years ago, to think that we'd even be talking about the possibility of the North Pole melting out in the summer, I would have never thought it.  If you talked to me or other scientists just a few years ago, we were saying that we might lose all or most of the summer sea ice cover by anywhere from 2050 to 2100.  Then, recently, we kind of revised those estimates, maybe as early as 2030. Now, there's people out there saying it might be even before that. So, things are happening pretty quick up there."

Some skeptics of global warming have also suggested that the melt is part of a cyclical process.  Flat out wrong, says Serreze.  He explains, "It's not cyclical at this point. I think we understand the physics behind this pretty well.  We've known for at least 30 years, from our earliest climate models, that it's the Arctic where we'd see the first signs of global warming."

Not above a bit of scolding of global warming skeptical, Serreze says, "It's a situation where we hate to say we told you so, but we told you so."

While Serreze says that the climate effects of warming may be damaging, there may be a bit of a silver lining for the time being in the clouds of global warming.  The disappearance of ice will allow oil to be saved on shipping routes by using the Northwest Passage.  Also, speaking of oil, there are large oil reserves at the pole.  In perhaps the greatest irony, global warming may free these reserves, which in turn will help contribute to more warming.

Much understanding remains to be developed of the causes, mechanics, and ramifications of warming, but as the stark face of reality rears its ugly head in the form of historic melting, it becomes clear that there's little room remaining for skepticism that massive climate change is indeed occurring.