|The McClure Strait in the Canadian Arctic has been fully open since early August [ESA] |
The Northwest Passage, the previously impassable shortcut between Europe and Asia in the Canadian Arctic, has now opened due to the shrinking of Arctic sea ice.
The European Space Agency (ESA) has said that sea ice has shrunk in the Arctic to its lowest level since satellite measurements began 30 years ago.
Leif Toudal Pedersen of the Danish National Space Centre said: "We have seen the ice-covered area drop to just around three million square kilometres, which is about one million square kilometres less than the previous minima of 2005 and 2006."
"There has been a reduction of the ice cover over the last 10 years of about 100,000 square km per year on average, so a drop of one million square km in just one year is extreme."
A shipping route through the Northwest Passage in the Canadian Arctic is viewed as a cheaper option to the Panama Canal for many shippers.
The most direct route of the Northwest Passage across northern Canada is now "fully navigable", while the so-called Northeast Passage along the Siberian coast "remains only partially blocked," ESA said.
While the Northeast Passage remained partially blocked, it may open sooner than expected, Pedersen said.
Scientists working with the UN's Intergovernmental Panel on Climate Change (IPCC) have warned that the Arctic is one of the most vulnerable areas for global warming, and some have predicted that the Arctic will be ice free by 2040.
Most experts say global warming is happening about twice as fast in the Arctic as elsewhere on the planet.
In August, William Chapman, a US Arctic specialist of the University of Illinois Champaign-Urbana, said that Arctic sea ice cover had already plunged to the lowest levels measured, 30 days before the normal point of the annual minimum.
|The orange line is said to indicate that the most direct route of|
the Northwest Passage is open [ESA]
The accelerated melting of Arctic ice is being driven by a phenomenon called albedo.
Albedo involves the reflectivity of light, as the ice sea has a bright surface, the majority of solar energy that strikes it is reflected back into space.
When sea ice melts, the dark-coloured ocean surface is exposed. Solar energy is then absorbed by the sea rather than reflected, so the oceans get warmer and temperatures rise, thus making it more difficult for new ice to form.
The dramatic loss of sea ice over the past few years has prompted competition among countries bordering the Arctic Ocean over navigation routes and the rights to its mineral-rich seabed.