Scientists from around the world have spent decades trying to answer the question: What happens when oil spills in ice?

As global temperatures climb and the Arctic sea ice melts, shipping in the Arctic is on the rise and oil and gas companies are eyeing further development of the vast resources of the North.

But when oil inevitably spills in the Arctic, scientists say it's going to be an entirely different scenario from what has played out in the Gulf of Mexico. Oil spills are nasty business no matter what, but when sub-zero temperatures, persistent darkness, remote locations and sea ice are thrown into the mix, the situation becomes exponentially more complex.

Despite the years of research into what happens when oil spills in ice, there remain more questions than answers. The problem, of course, is that no country is raising its hand to try spilling oil into the pristine Arctic environment to study what happens. The small spills that have occurred in the name of science, particularly in Norway, have been in controlled environments—far from the reality of what an Arctic spill could look like, with sparse resources, weather that is unpredictable at best and long, unforgiving periods of darkness.

An oil spill in the Arctic could happen in a number of ways. It could be a cruise ship that's run aground while passengers are looking at a sea bird colony. It could be a container ship that has its hull pierced below the water's surface. Or it could be a drilling disaster.

No matter the scenario, there are important questions to be asking now, before it's too late, such as what do we know about oil and ice? And what do we still not know?

What is it that makes ice so complicated?

Sea ice isn't some stable, uniform sheath that covers the Arctic Ocean. It shifts along cracks, called leads, and can vary greatly in thickness. In the lower reaches of the Arctic, the ice melts for a brief window in the summer, and then, within days, re-forms, first appearing like a greasy stain on the ocean's surface before it thickens.

It also doesn't stand still. Depending on the season, ice can drift at a rate exceeding 50 kilometers a day—even more at times. Ice north of Tuktoyaktuk, a village in Canada's Northwest Territories, was tracked over 2,000 kilometers between mid-October 2007 and mid-May 2008. That's nearly the distance between New York City and Miami.

As the Arctic warms, the thick sea ice that historically stuck around from year to year is melting and being replaced by annual sea ice that comes and goes with the seasons. This ice is thinner and more mobile, drifting faster than it did 100 years ago.

What are the different types of ice?

Land-fast ice is frozen along the shore, partially frozen to the seabed in shallow water, or anchored to underwater ridges in deeper water. But when severe storms come along—an increasing reality as there is more open ocean due to climate change—the land-fast ice can break away, becoming...

Drift Ice , which floats freely on the surface without any stable connection to land.

Pack Ice is drift ice that's thicker, though warming temperatures are changing the nature of this ice. A 2009 study found that from 1980 to 2008, mean Arctic sea ice thickness dropped from nearly 12 feet to just over six feet.

How difficult is it to respond to an accident in the Arctic?

In a word: very. That's why oil companies talk a lot about the precautions they're taking to avoid a spill.

But in the event that something did go wrong and responders weren't in position to deal with it immediately, the remote locations could result in long lag times between spill and response—time during which the oil could drift or continue to leak.

Compare the Arctic with the Gulf of Mexico. When oil spills in the Gulf, resources are nearby. And yet, in BP's Deepwater Horizon Spill five years ago, there were shortages of housing for responders. While some of the work continued around the clock in that disaster, the clean-up work on other spills in the Gulf has mostly taken place during daylight.

In the Arctic, daylight is not an option for much of the year. In Barrow, Alaska, the northernmost town in the U.S., the sun sets in November and does not rise above the horizon again for more than two months. At the North Pole, the darkness lasts from early October until early March. The weather can also be extreme. Spill responders can't work in temperatures colder than -40° Fahrenheit. As hard as that may be to imagine, it can be the reality in the Arctic.

What does this mean for spilled oil?

It all depends on a number of variables—such as when in the year the oil spills or the type of ice in the area. If oil spills in open water, there are models that can be used to track where it is likely to go. If it's during a season when there is sunlight, planes can locate it visually. Then it's not all that different from a spill that could happen anywhere in the U.S. (except for the lack of regional resources and the cold).

But when there is ice in the area—and for most of the year there is—it's an entirely different scenario.

What's a best-case scenario?

Oil spilled under new ice that is re-forming and expanding can become encapsulated—or frozen—into the undersurface of the ice. This actually would be a better-case scenario (because there is no "best-case scenario" for an oil spill), according to C.J. Beegle-Kraus, a senior scientist at Sintef, an independent Norwegian research organization. Sintef has been conducting experiments and modeling to determine what happens to oil in ice. She explains that if oil were spilled during the drilling process, first responders would be on hand, under federal requirements. So if the oil gets encapsulated on the underside of the ice, the responders could mark the ice and then follow it through the winter. In the spring thaw, they would theoretically be ready to clean it up.

But, of course, that's if everything goes right.

What if it's not a "better-case scenario"?

"The problem is that even if you drill in the summer, there may be production in the winter," says Nancy Kinner, a professor of civil and environmental engineering at the University of New Hampshire, where she heads up the Coastal Response Research Center in partnership with the National Oceanic and Atmospheric Administration. "They're not going to shut it down in the winter. They'll produce 24/7."

If there's a spill in the winter, responders have ice, cold and darkness to contend with.

If oil spills under the ice, there's still not much known about where it will go. Little is known about currents under the sea ice, either, which is part of the problem. Adding another wrinkle is that the Arctic climate is changing rapidly. So not only do scientists not know much about how ice and oil have historically interacted—they don't understand how new dynamics will affect that relationship, either.

A shipping accident may offer the worst-case scenario and potentially one of the more realistic possibilities, Kinner says. "Shipping in the Arctic is very dangerous," she said. "There are so many things that can go wrong, and there is so little support."

Right now not that many ships cross the Arctic. But that's projected to change in the near future.

Say the hull of a ship was punctured below the waterline as it crossed through icy water. If oil leaked and got trapped under the ice, it could get frozen into the underside, pushed up to the surface through leads in the ice, or spread underneath the ice and brought along as rough Arctic weather pushes it further from the initial source (remember New York to Miami?).

What other complications might there be?

Ocean flow patterns under the ice aren't just horizontal—they are vertical, too. That could make spilled oil even hard to track.

It could also depend on the type of oil. If it's heavy fuel oil, a marine oil commonly used in shipping, there is the possibility that the oil could sink to the ocean floor.

In 2010, a working group of the Arctic Council, an intergovernmental body with leaders from each of the Arctic nations, commissioned research firm Der Norske Veritas to look into what a spill of heavy fuel oil could mean for the Arctic. In its report, Der Norske Veritas noted that when oil is transported along with ice, it can be released when the ice melts in the spring. This is a particularly precarious time for Arctic ecosystems. The melting of seasonal sea ice triggers a cycle of life in the Arctic, kicking off a bloom of tiny organisms called phytoplankton, which then work their way up the food chain.

The bottom line, says Kinner, is that "even a relatively small amount of oil could have a big impact in the pristine Arctic."