Warming temperatures may melt sea ice in the Arctic to such a degree by midcentury that ships may be able to travel through previously inconceivable routes across the North Pole and through the famed Northwest Passage, according to a new study in the Proceedings of the National Academy of Sciences Plus.
The study breaks new ground in not just examining climate models of thinning ice but comparing them to maritime regulations for polar vessels. The findings of "Supra-Polar" routes also raise new geopolitical questions about disputed areas of the Arctic Ocean that are inaccessible now but may become contested navigable waterways in the future, the researchers said.
In some cases, ordinary shipping vessels may be able to travel into new parts of the Arctic without the help of icebreakers setting their path, as would typically be required today, said University of California, Los Angeles, geography professor Laurence Smith and UCLA doctoral candidate Scott Stephenson, the study's authors. Never-seen commercial pathways linking the Pacific and Atlantic oceans could open up, they said.
"We're talking about a future in which open-water vessels will, at least during some years, be able to navigate unescorted," Stephenson said.
The team examined several different climate models for future sea ice thickness and concentration through 2059 in September, when Arctic ice hits its lowest levels.
They then compared averages from the climate models to maritime rules that outline where, and how fast, certain classes of ships can traverse safely through various levels of ice thickness.
With that information, they calculated the fastest, feasible routes to get through points in Europe and Canada to the Bering Strait and back.
Thinning ice will eventually allow Polar Class 6 ships, or light icebreakers, to navigate between the Pacific and Atlantic oceans in September directly over the North Pole, the researchers said. That could cut their route by about 20 percent in comparison to today's options.
"At least during September, these [icebreaker] vessels will pretty much be able to go anywhere they want," said Smith, the study's lead author. "Nobody has ever talked about shipping over the North Pole before."
Different scenarios for passage
The Northwest Passage -- a famed linkage between the Pacific and Atlantic running along Canada's northern coastline -- also may become the fastest route for both icebreakers and regular open-water vessels with unstrengthened hulls going to and from eastern North America, Smith and Stephenson said. These open-water vessels make up almost all of the world's shipping fleet.
Up to 2005, the probability of a feasible route through the Northwest Passage for ordinary open-water vessels during any given year was less than 15 percent. By 2059, the probability will rise to as much as 60 percent, the study says.
Currently, the Northwest Passage is "theoretically navigable" now for one out of every seven years, although it is not an option for commercial shipping because of economic and safety challenges. Eventually, September ice will be thin enough to create robust shipping routes in the passage every other year, the researchers said.
Without ice barriers, the Northwest Passage is the most direct route from Asia to eastern Canada and the northeast United States and would cut the distance for vessels by roughly 30 percent from the current most-trafficked pathway.
Additionally, the Northern Sea Route -- an Arctic lane along the Russian coast used by ships now -- will become more attractive to ordinary shipping vessels, as well, a development that would challenge Russia's existing monopoly over much Arctic traffic. Russia currently charges fees to vessels moving through the Northern Sea Route.
Smith said the new robust routes across the Arctic appear under two different climate change scenarios -- one considers global carbon emissions to rise 25 percent, while the other assumes a more moderate 10 percent rise in CO2.
"The Arctic waters will become open regardless of which climate change mitigation strategies we may or may not adopt," he said.
The Arctic is warming twice as fast as the global average, according to scientists.
Tankers, tourism and regulations
Ron Lindsay, an Arctic expert in the Polar Science Center at the University of Washington who did not participate in the research, said that the "future is here" in regard to the Arctic. He noted that several ships made roundtrip journeys through the Northern Sea Route last summer. At the same time, climate models have enough variation to make a precise prediction of future sea routes difficult, he said.
The basic premise of the study is accurate, "but I don't trust any of the details," Lindsay said.
Shorter shipping routes have the potential to reduce CO2 emissions from ships, but they also would result in greater emissions of black carbon and sulfate within the Arctic, which is uniquely vulnerable to additional warming from pollution, said Mark Flanner, a scientist at the University of Michigan who did not participate in the study.
"As the authors state, the potential for Arctic shipping in the near future therefore increases the urgency for a regulatory [International Maritime Organization] framework that guarantees proper environment and climate stewardship for this region," he said. Current guidelines for ships operating in the Arctic are voluntary.
Smith said the research raises numerous policy questions, including who oversees the Northwest Passage. Canada maintains that the route falls under its jurisdiction, while the United States says it is an international strait, he said.
"At the moment, the two countries agree to disagree, because it doesn't currently matter," he said. "But that could change if there is shipping."
The possibility of new Arctic lanes could play into an ongoing debate about whether the United States should ratify the U.N. Convention on the Law of the Sea, which governs navigation, environmental issues and oil and gas development. The framework also allows member nations to apply to extract oil, gas and mineral deposits beyond a 200-mile exclusive economic zone (ClimateWire, June 29, 2012).
The research should not be interpreted to mean that there will be automatic, rampant shipping in the Arctic, said Smith. Fuel costs and port locations are among the many economic and safety considerations that will determine where ships actually go, he said. Additionally, the new routes will remain a summer option only, he said.
What is certain is that there will be new temptations for tourism companies and for bulk tankers carrying natural resources out of the Arctic to Asia, Smith said.
"This is an iconic, fragile place," he said. "We better get it right."