NEW YORK (REUTERS) - Thawing permafrost could put as much as 50 per cent of Arctic infrastructure at high risk of damage by 2050, requiring tens of billions of dollars in maintenance and repairs, scientists warned on Tuesday.
The world's permafrost - land that remains frozen year-round - has been warming at between 0.3 and 1 deg C per decade since the 1980s, with some areas of the high Arctic having increased by more than 3 deg C over four decades, according to a scientific review of research from the past two decades published in the journal Nature Reviews Earth & Environment.
That is enough to thaw much of the long-frozen ground.
Already, some roads are buckling and building foundations are cracking in northern Russia, Alaska and Canada.
"Infrastructure is in trouble," said report co-author Dmitry Streletskiy, a geographer at George Washington University. "But it is not like an earthquake. It is a relatively slow process, which gives us enough time" to prevent some damage.
Scientists say this trend will continue as climate change escalates. From satellite imagery, they estimate that at least 120,000 buildings, 40,000km of roads and 9,500km of pipelines could be at risk, highlighting threats to some Canadian highways, the Trans-Alaska Pipeline System, and the Russian cities of Vorkuta, Yakutsk and Norilsk.
But people are still building in the Arctic. Satellite images show that coastal infrastructure has increased by 15 per cent, or 180 sq km, since 2000, according to another study published last year in the journal Environmental Research Letters.
About 70 per cent of that growth is linked to the oil and gas industry, especially on Russia's Yamal Peninsula and near the Yamburg gas field, according to that study's lead author, polar researcher Annett Bartsch, who is with the Austrian-based b.geos research and consultancy group.
"There are a lot of new roads and rail tracks," she said.
Engineers use several costly strategies when building on permafrost. For example, they place heat-diverting pipes along roads and building foundations to help keep the frozen ground stable.
Maintenance costs for major infrastructure could increase by US$15.5 billion (S$20.9 billion) by mid-century but would still be unable to prevent some US$21.6 billion in damages, according to the review paper's most conservative estimates.
For decades, researchers have focused on monitoring the carbon long locked in permafrost, worrying that the release of climate-warming carbon dioxide and methane could push the world towards runaway global warming.
But "the impact on infrastructure is already happening today", said Dr Vladimir Romanovsky, a geophysicist at the University of Alaska Fairbanks whose research was among the more than 160 studies assessed in the review. "It is much more urgent for people who live and work on permafrost."