Posted on behalf of Sid Perkins.
When it comes to Arctic transportation in the coming decades, melting ice will giveth, and melting ice will taketh away.
By the middle of this century, several routes across and around the Arctic Ocean now at least partially blocked by sea ice will become fully open to some ships during summer months, a new analysis suggests. At the same time, warmer temperatures will render broad swaths of Arctic terrain now reachable in winter via ice roads inaccessible by land. Scientists have long suspected such changes would come to pass as warming progressed, but the new study — led by Scott Stephenson, a physical geographer at the University of California, Los Angeles and published online today in Nature Climate Change — is the first to quantify the effects.
If sea ice is more than 1.2 metres thick, ships with limited ice-breaking ability, or so-called “Type A” ships, can’t proceed. And even when ice is thinner than 1.2 m, the ships often aren’t allowed to travel full speed ahead. But by mid-century, almost 4.2 million square kilometres of Arctic Ocean now clogged with sea ice — including more than 1.8 million square kilometres that lie in international waters — will be essentially ice-free from July through September, enabling rapid transit along several potentially lucrative Arctic passages.
For example, the route from Rotterdam northward through the North Sea, across the Arctic Ocean, and southward through the Bering Strait to Yokohama, Japan, is 40 percent shorter than the warm-water path that connects the two cities through the Suez Canal and could be traversed in a mere 11 days, the researchers estimate.
The downside of warmer temperatures, however, is that in winter the temporary roads constructed across frozen ground, lakes or rivers may not support the weight of supply vehicles. Ice roads, which are much less costly to build and maintain than highways designed to resist harsh winter conditions, enable the economical shipment of equipment and supplies to mining, energy exploration and timber industries in sparsely populated regions.
By 2050, Stephenson and his colleagues estimate, inland regions of the Arctic totalling more than 1.2 million square kilometres — the vast majority of which lie within Canada and Russia — will become completely inaccessible to vehicles weighing more than a mid-sized sedan. Without those winter roads, supplies would have to be shipped via slow ferries or airlift. “This has the potential to render operations in some areas uneconomical,” says Stephenson.
Even now, prices charged for perishable items when ice roads are passable are vastly lower than the spring when the roads melt. “I’ve been in one of these towns just after the spring thaw,” says Stephenson. “As soon as a winter road closes, you can tell the difference at the cash register.”
Image of ice road courtesy of madmack66 via Flickr under Creative Commons.