In 1942 the Alaska Highway was built as an Army Supply route, with the goal of connecting the 49th state with the contiguous U.S. It was an epic task that involved carving through mountainous arctic forest. Following World War II the 1,500 mile road – which traverses British Columbia, the Yukon, and Alberta – was noted for its ruggedness.
The Alaskan reach of the highway was paved early in the 1960s. By the 1980s most of Canadian portions were smoothed out. The last gravel stretch of the highway was tamed by asphalt in 1992.
The Alaska Highway was considered a 20th Century engineering marvel. But today, in its 70th year, it’s morphing back into a rough ride. And we have climate change to thank.
Much of the Alaska Highway is built on permafrost that was historically frozen year after year. In our warming world, permafrost is now undergoing seasonal melting, causing overlying highway to buckle, crack, and otherwise break down.
Once predictable, permafrost has become the monkey-wrench in engineering roads in cold regions.
The world is warming the fastest in the northern latitudes. And the nature of pavement is adding to the already complex problem. Asphalt-covered roads absorb the sun’s heat, contributing to the melting of the permafrost.
Engineers are working to develop cost-effective light colored pavement. They are also innovating ways of mapping permafrost and insulating vulnerable stretches of roadway. But in the long term, unless major changes are made to our carbon diet, we had better get used to bumpy roads.
Web Links
http://news.discovery.com/earth/alaska-highway-at-70-warming-cracking-and-sinking-120725.html
http://www.livescience.com/3997-ground-frozen-ice-age-thaws-collapses.html
Photo, taken on March 22, 2006, courtesy of Ed Coyle via Flickr.