Northwest Passage

Routes

The Northwest Passage has three sections:

East

East of Baffin Island: Baffin Bay between Greenland and Baffin Island to Lancaster Sound at the north end of Baffin Island, or

West of Baffin Island (impractical): Through Hudson Strait south of Baffin Island, north through the Foxe Basin, west through the Fury and Hecla Strait, north to Lancaster Sound through the Gulf of Boothia and Prince Regent Inlet. The Fury and Hecla Strait is usually closed by ice.

Centre: Canadian Arctic Archipelago

North: From Lancaster Sound west through the Parry Channel to the Prince of Wales Strait on the northwest side of Victoria Island. M'Clure Strait to the northwest is ice-filled; southwest through the Prince of Wales Strait between Victoria Island and Banks Island might be passable, or

South: From Lancaster Sound west past Prince Regent Inlet (basically a cul-de-sac but it may be possible to exit west through the Bellot Strait), past Somerset Island, south through Peel Sound between Somerset Island and Prince of Wales Island, either southwest through Victoria Strait (ice-choked), or directly south along the coast through Rae Strait and James Ross Strait and west through Simpson Strait south of King William Island (shallow) into Queen Maud Gulf, then west along the mainland coast south of Victoria Island.

West: There being no major islands, follow the coast to the Bering Strait.

Many attempts were made to find a salt water exit west from Hudson Bay, but the Fury and Hecla Strait in the far north is blocked by ice. The eastern entrance and main axis of the northwest passage, the Parry Channel, was found in 1819. The approach from the west through Bering Strait is impractical because of the need to sail around ice near Point Barrow. East of Point Barrow the coast is fairly clear in summer. This area was mapped in pieces from overland in 1821–1839. This leaves the large rectangle north of the coast, south of Parry Channel and west of Baffin Island. This area was mostly mapped in 1848–1854 by ships looking for Franklin's lost expedition. The first crossing was made by Roald Amundsen in 1903–1906. He used a small ship and hugged the coast.

Overview

Early expeditions

Before the Little Ice Age (late Middle Ages to the 19th century), Norwegian Vikings sailed as far north and west as Ellesmere Island, Skraeling Island and Ruin Island for hunting expeditions and trading with the Inuit and people of the Dorset culture who inhabited the region. Between the end of the 15th century and the 20th century, colonial powers from Europe dispatched explorers to discover a commercial sea route north and west around North America. The Northwest Passage represented a new route to the established trading nations of Asia.

England called the hypothetical northern route the "Northwest Passage". The desire to establish such a route motivated much of the European exploration of both coasts of North America. When it became apparent that there was no route through the heart of the continent, attention turned to the possibility of a passage through northern waters. There was a lack of scientific knowledge about conditions; for instance, some people believed that seawater was incapable of freezing. (As late as the mid-18th century, Captain James Cook had reported that Antarctic icebergs had yielded fresh water, seemingly confirming the hypothesis.) Explorers thought that an Open Polar Sea close to the North Pole must exist. The belief that a route lay to the far north persisted for several centuries and led to numerous expeditions into the Arctic. Many ended in disaster, including that by Sir John Franklin in 1845. While searching for him the McClure Arctic Expedition discovered the Northwest Passage in 1850.

In 1906, the Norwegian explorer Roald Amundsen was the first to complete the passage solely by ship, from Greenland to Alaska in the sloop Gjøa. Since that date, several ice-fortified ships have made the journey.

From east to west, the direction of most early exploration attempts, expeditions entered the passage from the Atlantic Ocean via the Davis Strait and through Baffin Bay, both of which are in Canada. Five to seven routes have been taken through the Canadian Arctic Archipelago, via the McClure Strait, Dease Strait, and the Prince of Wales Strait, but not all of them are suitable for larger ships. From there ships passed through westward through the Beaufort Sea and the Chukchi Sea, and then southwards through the Bering Strait (separating Russia and Alaska), into the Pacific Ocean.

Potential as a shipping lane

In the 21st century, major changes to the ice pack due to climate change have stirred speculation that the passage may become clear enough of ice to permit safe commercial shipping for at least part of the year. On August 21, 2007, the Northwest Passage became open to ships without the need of an icebreaker. According to Nalan Koc of the Norwegian Polar Institute, this was the first time the Passage has been clear since they began keeping records in 1972. The Northwest Passage opened again on August 25, 2008. It is usually reported that ocean thawing will open up the Northwest Passage (and the Northern Sea Route) for various kind of ships, making it possible to sail around the Arctic ice cap and possibly cutting thousands of miles off shipping routes. Warning that the NASA satellite images suggested that the Arctic had entered a "death spiral" caused by climate change, Professor Mark Serreze, a sea ice specialist at the U.S. National Snow and Ice Data Center (NSIDC) said: "The passages are open. It's a historic event. We are going to see this more and more as the years go by."

However, some thick sections of ice will remain hard to melt in the shorter term. Drifting and persistence of large chunks of ice, especially in springtime, can be problematic as they can clog entire straits or severely damage a ship's hull. Cargo routes may thus be slow and uncertain, depending on prevailing conditions and the ability to predict them. Because much containerized traffic operates in a just-in-time mode (which does not tolerate delays well) and because of the relative isolation of the passage (which impedes shipping companies from optimizing their operations by grouping multiple stopovers on the same itinerary), the Northwest Passage and other Arctic routes are not always seen as promising shipping lanes by industry insiders, at least for the time being. The uncertainty related to physical damage to ships is also thought to translate into higher insurance premiums, especially because of the technical challenges posed by Arctic navigation (as of 2014, only 12 percent of Canada's Arctic waters have been charted to modern standards). A 2025 study suggests that although the navigability may increase over time, reliable planning requires explicit consideration of highly variable ice conditions.

The Beluga group of Bremen, Germany, sent the first Western commercial vessels through the Northern Sea Route (Northeast Passage) in 2009. Canada's Prime Minister Stephen Harper announced that "ships entering the North-West passage should first report to his government".

Extent

The International Hydrographic Organization defines the limits of the Northwestern Passages as follows:

On the West. The Eastern limit of Beaufort Sea from Lands End through the Southwest coast of Prince Patrick Island to Griffiths Point, thence a line to Cape Prince Alfred, the Northwestern extreme of Banks Island, through its West coast to Cape Kellet, the Southwestern point, and thence a line to Cape Bathurst on the mainland (70°36′N 127°32′W).

On the Northwest. The Arctic Ocean between Lands End, Prince Patrick Island, and Cape Columbia, Ellesmere Island.

On the Northeast. The Coast of Ellesmere Island between C. Columbia and C. Sheridan the Northern limit of Baffin Bay.

On the East. The East Coast of Ellesmere Island between C. Sheridan and Cape Norton Shaw (76°29′N 78°30′W), thence across to Phillips Point (Coburg Island) through this Island to Marina Peninsula (75°55′N 79°10′W) and across to Cape Fitz Roy (Devon Island) down the East Coast to Cape Sherard (Cape Osborn) (74°35′N 80°30′W) and across to Cape Liverpool, Bylot Island (73°44′N 77°50′W); down the East coast of this island to Cape Graham Moore, its southeastern point, and thence across to Cape Macculloch (72°29′N 75°08′W) and down the East coast of Baffin Island to East Bluff, its Southeastern extremity, and thence the Eastern limit of Hudson Strait.

On the South. The mainland coast of Hudson Strait; the Northern limits of Hudson Bay; the mainland coast from Beach Point to Cape Bathurst.

Historical expeditions

As a result of their westward explorations and their settlement of Greenland, the Vikings sailed as far north and west as Ellesmere Island, Skraeling Island for hunting expeditions and trading with Inuit groups. The subsequent arrival of the Little Ice Age is thought to have been one of the reasons that European seafaring into the Northwest Passage ceased until the late 15th century.

Strait of Anián

In 1539, Hernán Cortés commissioned Francisco de Ulloa to sail along the Baja California Peninsula on the western coast of North America. Ulloa concluded that the Gulf of California was the southernmost section of a strait supposedly linking the Pacific with the Gulf of Saint Lawrence. His voyage perpetuated the notion of the Island of California and saw the beginning of a search for the Strait of Anián.

The strait probably took its name from Ania, a Chinese province mentioned in a 1559 edition of Marco Polo's book; it first appears on a map issued by Italian cartographer Giacomo Gastaldi about 1562. Five years later Bolognino Zaltieri issued a map showing a narrow and crooked Strait of Anian separating Asia from the Americas. The strait grew in European imagination as an easy sea lane linking Europe with the residence of Khagan (the Great Khan) in Cathay (northern China).

Cartographers and seamen tried to demonstrate its reality. Sir Francis Drake sought the western entrance in 1579. The Greek pilot Juan de Fuca, sailing from Acapulco (in Mexico) under the flag of the Spanish crown, claimed he had sailed the strait from the Pacific to the North Sea and back in 1592. The Spaniard Bartholomew de Fonte claimed to have sailed from Hudson Bay to the Pacific via the strait in 1640.

Northern Atlantic

The first recorded attempt to discover the Northwest Passage was the east–west voyage of John Cabot in 1497, sent by Henry VII in search of a direct route to the Orient. In 1524, Charles V sent Estêvão Gomes to find a northern Atlantic passage to the Spice Islands. An English expedition was launched in 1576 by Martin Frobisher, who took three trips west to what is now the Canadian Arctic in order to find the passage. Frobisher Bay, which he first charted, is named after him.

As part of another expedition, in July 1583 Sir Humphrey Gilbert, who had written a treatise on the discovery of the passage and was a backer of Frobisher, claimed the territory of Newfoundland for the English crown. On August 8, 1585, the English explorer John Davis entered Cumberland Sound, Baffin Island.

The major rivers on the east coast were also explored in case they could lead to a transcontinental passage. Jacques Cartier's explorations of the Saint Lawrence River in 1535 were initiated in hope of finding a way through the continent. Cartier became persuaded that the St. Lawrence was the Passage; when he found the way blocked by rapids at what is now Montreal, he was so certain that these rapids were all that was keeping him from China (in French, la Chine), that he named the rapids for China. Samuel de Champlain renamed them Sault Saint-Louis in 1611, but the name was changed to Lachine Rapids in the mid-19th century.

In 1602, George Weymouth became the first European to explore what would later be called Hudson Strait when he sailed Discovery 300 nautical miles (560 km) into the Strait. Weymouth's expedition to find the Northwest Passage was funded jointly by the British East India Company and the Muscovy Company. Discovery was the same ship used by Henry Hudson on his final voyage.

John Knight, employed by the British East India Company and the Muscovy Company, set out in 1606 to follow up on Weymouth's discoveries and find the Northwest Passage. After his ship ran aground and was nearly crushed by ice, Knight disappeared while searching for a better anchorage.

In 1609, Henry Hudson sailed up what is now called the Hudson River in search of the Passage; encouraged by the saltiness of the water in the estuary, he reached present-day Albany, New York, before giving up. On September 14, 1609, Hudson entered the Tappan Zee while sailing upstream from New York Harbor. At first, Hudson believed the widening of the river indicated that he had found the Northwest Passage. He proceeded upstream as far as present-day Troy before concluding that no such strait existed there. He later explored the Arctic and Hudson Bay.

Northern Pacific

Most Northwest Passage expeditions originated in Europe or on the east coast of North America, seeking to traverse the Passage in the westbound direction. Some progress was made in exploring the western reaches of the imagined passage.

In 1728 Vitus Bering, a Danish-born Russian navy officer, used the strait first discovered by Semyon Dezhnyov in 1648 but later accredited to and named after Bering (the Bering Strait). He concluded that North America and Russia were separate land masses by sailing between them. In 1741 with Lieutenant Aleksei Chirikov, he explored seeking further lands beyond Siberia. While they were separated, Chirikov discovered several of the Aleutian Islands while Bering charted the Alaskan region. His ship was wrecked off the Kamchatka Peninsula, as many of his crew were disabled by scurvy.

The Spanish made several voyages to the northwest coast of North America during the late 18th century. Determining whether a Northwest Passage existed was one of the motives for their efforts. Among the voyages that involved careful searches for a Passage included the 1775 and 1779 voyages of Juan Francisco de la Bodega y Quadra. The journal of Francisco Antonio Mourelle, who served as Quadra's second in command in 1775, fell into English hands. It was translated and published in London, stimulating exploration.

Captain James Cook made use of the journal during his explorations of the region. In 1791 Alessandro Malaspina sailed to Yakutat Bay, Alaska, which was rumoured to be a Passage. In 1790 and 1791 Francisco de Eliza led several exploring voyages into the Strait of Juan de Fuca, searching for a possible Northwest Passage and finding the Strait of Georgia. To fully explore this new inland sea, an expedition under Dionisio Alcalá Galiano was sent in 1792. He was explicitly ordered to explore all channels that might turn out to be a Northwest Passage.

Cook and Vancouver

In 1776, Captain James Cook was dispatched by the Admiralty in Great Britain on an expedition to explore the Passage. A 1745 act, when extended in 1775, promised a £20,000 prize for whoever discovered the passage. Initially the Admiralty had wanted Charles Clerke to lead the expedition, with Cook (in retirement following his exploits in the Pacific) acting as a consultant. However, Cook had researched Bering's expeditions, and the Admiralty ultimately placed their faith in the veteran explorer to lead, with Clerke accompanying him.

After journeying through the Pacific, to make an attempt from the west, Cook began at Nootka Sound in April 1778. He headed north along the coastline, charting the lands and searching for the regions sailed by the Russians 40 years previously. The Admiralty's orders had commanded the expedition to ignore all inlets and rivers until they reached a latitude of 65°N. Cook, however, failed to make any progress in sighting a Northwestern Passage.

Various officers on the expedition, including William Bligh, George Vancouver, and John Gore, thought the existence of a route was 'improbable'. Before reaching 65°N they found the coastline pushing them further south, but Gore convinced Cook to sail on into the Cook Inlet in the hope of finding the route. They continued to the limits of the Alaskan peninsula and the start of the 1,200 mi (1,900 km) chain of Aleutian Islands. Despite reaching 70°N, they encountered nothing but icebergs.

From 1792 to 1794, the Vancouver Expedition (led by George Vancouver who had previously accompanied Cook) surveyed in detail all the passages from the Northwest Coast. He confirmed that there was no such passage south of the Bering Strait. This conclusion was supported by the evidence of Alexander MacKenzie, who explored the Arctic and Pacific Oceans in 1793.

19th century

In the first half of the 19th century, some parts of the Northwest Passage (north of the Bering Strait) were explored separately by many expeditions, including those by John Ross, Elisha Kent Kane, William Edward Parry, and James Clark Ross; overland expeditions were also led by John Franklin, George Back, Peter Warren Dease, Thomas Simpson, and John Rae. In 1826 Frederick William Beechey explored the north coast of Alaska, discovering Point Barrow.

Sir Robert McClure was credited with the discovery of the Northwest Passage in 1851 when he looked across McClure Strait from Banks Island and viewed Melville Island. However, this strait was not navigable to ships at that time. The only usable route linking the entrances of Lancaster Sound and Dolphin and Union Strait was discovered by John Rae in 1854.

Franklin expedition

In 1845, a lavishly equipped two-ship expedition led by Sir John Franklin sailed to the Canadian Arctic to chart the last unknown swaths of the Northwest Passage. Confidence was high, as they estimated there was less than 500 km (310 mi) remaining of unexplored Arctic mainland coast. When the ships failed to return, relief expeditions and search parties explored the Canadian Arctic, which resulted in a thorough charting of the region, along with a possible passage. Many artifacts from the expedition were found over the next century and a half, including notes that the ships were ice-locked in 1846 near King William Island, about halfway through the passage, and unable to break free. Records showed Franklin died in 1847 and Captain Francis Crozier took over command. In 1848 the expedition abandoned the two ships and its members tried to escape south across the tundra by sledge. Although some of the crew may have survived into the early 1850s, no evidence has ever been found of any survivors. In 1853, explorer John Rae was told by local Inuit about the disastrous fate of Franklin's expedition, but his reports were not welcomed in Britain on account of his reports of cannibalism amongst the surviving crews.

Starvation, exposure and scurvy all contributed to the men's deaths. In 1981 Owen Beattie, an anthropologist from the University of Alberta, examined remains from sites associated with the expedition. This led to further investigations and the examination of tissue and bone from the frozen bodies of three seamen, John Torrington, William Braine and John Hartnell, exhumed from the permafrost of Beechey Island. Laboratory tests revealed high concentrations of lead in all three (the expedition carried 8,000 tins of food sealed with a lead-based solder). Another researcher has suggested botulism caused deaths among crew members. Evidence from 1996, that confirms reports first made by John Rae in 1854 based on Inuit accounts, suggests that the last of the crew may have resorted to cannibalism of deceased members in an effort to survive.

McClure expedition

During the search for Franklin, Commander Robert McClure and his crew in HMS Investigator traversed the Northwest Passage from west to east in the years 1850 to 1854, partly by ship and partly by sledge. McClure started out from England in December 1849, sailed the Atlantic Ocean south to Cape Horn and entered the Pacific Ocean. He sailed the Pacific north and passed through the Bering Strait, turning east at that point and reaching Banks Island.

McClure's ship was trapped in the ice for three winters near Banks Island, at the western end of Viscount Melville Sound. Finally McClure and his crew—who were by that time dying of starvation—were found by searchers who had travelled by sledge over the ice from a ship of Sir Edward Belcher's expedition. They rescued McClure and his crew, returning with them to Belcher's ships, which had entered the Sound from the east. McClure and his crew returned to England in 1854 on one of Belcher's ships. They were the first people known to circumnavigate the Americas and to discover and transit the Northwest Passage, albeit by ship and by sledge over the ice. (Both McClure and his ship were found by a party from HMS Resolute, one of Belcher's ships, so his sledge journey was relatively short.)

This was an astonishing feat for that day and age, and McClure was knighted and promoted in rank. (He was made rear-admiral in 1867.) Both he and his crew also shared £10,000 awarded them by the British Parliament. In July 2010 Canadian archaeologists found his ship, HMS Investigator, fairly intact but sunk about 8 m (26 ft) below the surface.

John Rae

The expeditions by Franklin and McClure were in the tradition of British exploration: well-funded ship expeditions using modern technology, and usually including British Naval personnel. By contrast, John Rae was an employee of the Hudson's Bay Company, which operated a far-flung trade network and drove exploration of the Canadian North. They adopted a pragmatic approach and tended to be land-based. While Franklin and McClure tried to explore the passage by sea, Rae explored by land. He used dog sleds and techniques of surviving in the environment which he had learned from the native Inuit. The Franklin and McClure expeditions each employed hundreds of personnel and multiple ships. John Rae's expeditions included fewer than ten people and succeeded. Rae was also the explorer with the best safety record, having lost only one man in years of traversing Arctic lands. In 1854, Rae returned to the cities with information from the Inuit about the disastrous fate of the Franklin expedition.

Amundsen expedition

The first explorer to traverse the Northwest Passage solely by ship was the Norwegian explorer Roald Amundsen. In a three-year journey between 1903 and 1906, Amundsen explored the passage with a crew of six. Amundsen, who had sailed to escape creditors seeking to stop the expedition, completed the voyage in the converted 45 net register tonnage (4,500 cu ft or 130 m3) herring boat Gjøa. Gjøa was much smaller than vessels used by other Arctic expeditions and had a shallow draft. Amundsen intended to hug the shore, live off the limited resources of the land and sea through which he was to travel, and had determined that he needed to have a tiny crew to make this work. (Trying to support much larger crews had contributed to the catastrophic failure of John Franklin's expedition fifty years previously, losing two ships and their crews). The ship's shallow draft was intended to help her traverse the shoals of the Arctic straits.

Amundsen set out from Kristiania (Oslo) in June 1903 and was west of the Boothia Peninsula by late September. Gjøa was put into a natural harbour on the south shore of King William Island; by October 3 she was iced in. There the expedition remained for nearly two years, with the expedition members learning from the local Inuit and undertaking measurements to determine the location of the North Magnetic Pole. The harbour, now known as Gjoa Haven, later developed as the only permanent settlement on the island.

After completing the Northwest Passage portion of this trip and having anchored near Herschel Island, Amundsen skied 800 kilometres (500 mi) to the city of Eagle, Alaska. He sent a telegram announcing his success and skied the return 800 kilometres (500 mi) to rejoin his companions. Although his chosen east–west route, via the Rae Strait, contained young ice and thus was navigable, some of the waterways were extremely shallow (3 ft (0.91 m) deep), making the route commercially impractical.

Later expeditions

The first traversal of the Northwest Passage via dog sled was accomplished by Greenlander Knud Rasmussen while on the Fifth Thule Expedition (1921–1924). Rasmussen and two Greenland Inuit travelled from the Atlantic to the Pacific over the course of 16 months via dog sled.

Canadian Royal Canadian Mounted Police officer Henry Larsen was the second to sail the passage, crossing west to east, leaving Vancouver on June 23, 1940, and arriving at Halifax on October 11, 1942. More than once on this trip, he was uncertain whether St. Roch, a Royal Canadian Mounted Police "ice-fortified" schooner, would survive the pressures of the sea ice. At one point, Larsen wondered "if we had come this far only to be crushed like a nut on a shoal and then buried by the ice." The ship and all but one of her crew survived the winter on Boothia Peninsula. Each of the men on the trip was awarded a medal by Canada's sovereign, King George VI, in recognition of this feat of Arctic navigation.

Later in 1944, Larsen's return trip was far more swift than his first. He made the trip in 86 days to sail back from Halifax, Nova Scotia, to Vancouver, British Columbia. He set a record for traversing the route in a single season. The ship, after extensive upgrades, followed a more northerly, partially uncharted route.

In 1954, HMCS Labrador completed the east-to-west transit, under the command of Captain O.C.S. Robertson, conducting hydrographic soundings along the route. She was the first warship (and the first deep draft ship) to transit the Northwest Passage and the first warship to circumnavigate North America. In 1956, HMCS Labrador again completed the east-to-west transit, this time under the command of Captain T.C. Pullen.

On July 1, 1957, the United States Coast Guard Cutter Storis departed in company with USCGC Bramble and USCGC Spar to search for a deep-draft channel through the Arctic Ocean and to collect hydrographic information. The US Coast Guard Squadron was escorted through Bellot Strait and the Eastern Arctic by HMCS Labrador. Upon her return to Greenland waters, Storis became the first U.S.-registered vessel to circumnavigate North America. Shortly after her return in late 1957, she was reassigned to her new home port of Kodiak, Alaska.

In 1960, USS Seadragon completed the first submarine transit of the Northwest Passage, heading east-to-west.

International waters dispute

The Canadian government classifies the waters of the Northwest Passage in the Canadian Arctic Archipelago, as internal waters of Canada as per the United Nations Convention on the Law of the Sea and by the precedent in the drawing of baselines for other archipelagos, giving Canada the right to bar transit through these waters. Some maritime nations, notably the United States, claim these waters to be an international strait, where foreign vessels have the right of "transit passage." In such a regime, Canada would have the right to enact fishing and environmental regulation, and fiscal and smuggling laws, as well as laws intended for the safety of shipping, but not the right to close the passage. While Canada is a party to the 1982 convention, the United States has not ratified it.

The dispute between Canada and the United States arose in 1969 with the trip of the U.S. oil tanker SS Manhattan through the Arctic Archipelago. The prospect of more American traffic headed to the Prudhoe Bay Oil Field made the Canadian government realize that political action was required. If the passage's deep waters become completely ice-free in summer months, they will be particularly enticing for supertankers that are too big to pass through the Panama Canal and must otherwise navigate around the tip of South America.

In 1985, the U.S. Coast Guard icebreaker Polar Sea passed through from Greenland to Alaska; the ship submitted to inspection by the Canadian Coast Guard before passing through, but the event infuriated the Canadian public and resulted in a diplomatic incident. The United States government, when asked by a Canadian reporter, indicated that it did not ask for permission as it insists that the waters were an international strait. The Canadian government issued a declaration in 1986 reaffirming Canadian rights to the waters. The United States refused to recognize the Canadian claim. In 1988 the governments of Canada and the United States signed an agreement, "Arctic Cooperation," that resolved the practical issue without solving the sovereignty questions. Under the law of the sea, ships engaged in transit passage are not permitted to engage in research. The agreement states that all U.S. Coast Guard and Navy vessels are engaged in research, and so would require permission from the Government of Canada to pass through.

However, in late 2005, it was reported that U.S. nuclear submarines had travelled unannounced through Canadian Arctic waters, breaking the "Arctic Cooperation" agreement and sparking outrage in Canada. In his first news conference after the 2006 federal election, Prime Minister-designate Stephen Harper contested an earlier statement made by the U.S. ambassador that Arctic waters were international, stating the Canadian government's intention to enforce its sovereignty there. The allegations arose after the U.S. Navy released photographs of USS Charlotte surfaced at the North Pole.

Thinning ice cover and the Northwest Passage

In summer 2000, two Canadian ships took advantage of thinning summer ice cover on the Arctic Ocean to make the crossing. It is thought that climate change is likely to open the passage for increasing periods, making it potentially attractive as a major shipping route. However, the passage through the Arctic Ocean would require significant investment in escort vessels and staging ports, and it would remain seasonal. Therefore, the route has not become a viable alternative to the Panama Canal.

On September 14, 2007, the European Space Agency (ESA) stated that ice loss that year had opened up the historically impassable passage, setting a new low of ice cover as seen in satellite measurements which went back to 1978. According to the Arctic Climate Impact Assessment, the latter part of the 20th century and the start of the 21st had seen marked shrinkage of ice cover. The extreme loss in 2007 rendered the passage "fully navigable." However, the ESA study was based only on analysis of satellite images and could in practice not confirm anything about the actual navigation of the waters of the passage. ESA suggested the passage would be navigable "during reduced ice cover by multi-year ice pack" (namely sea ice surviving one or more summers) where previously any traverse of the route had to be undertaken during favourable seasonable climatic conditions or by specialist vessels or expeditions. The agency's report speculated that the conditions prevalent in 2007 had shown the passage may "open" sooner than expected. An expedition in May 2008 reported that the passage was not yet continuously navigable even by an icebreaker and not yet ice-free.

Scientists at a meeting of the American Geophysical Union on December 13, 2007, revealed that NASA satellites observing the western Arctic showed a 16% decrease in cloud coverage during the summer of 2007 compared to 2006. This would have the effect of allowing more sunlight to penetrate Earth's atmosphere and warm the Arctic Ocean waters, thus melting sea ice and contributing to opening the Northwest Passage.

However more recent observations show that the annual window for safe shipping in the Arctic ocean is shrinking, apparently because rapid melting of thin sea ice allows thicker multiyear ice to move around and clog ship channels.

Transfer of Pacific species to North Atlantic

Scientists believe that reduced sea ice in the Northwest Passage has permitted some new species to migrate across the Arctic Ocean. The gray whale Eschrichtius robustus has not been seen in the Atlantic since it was hunted to extinction there in the 18th century, but in May 2010, one such whale turned up in the Mediterranean. Scientists speculated the whale had followed its food sources through the Northwest Passage and simply kept on going.

The plankton species Neodenticula seminae had not been recorded in the Atlantic for 800,000 years. However, it has become increasingly prevalent there. Again, scientists believe that it got there through the reopened Northwest Passage.

In August 2010, two bowhead whales from West Greenland and Alaska respectively, entered the Northwest Passage from opposite directions and spent approximately 10 days in the same area.