IPCC_Managing Risks of Extreme Events.pdf - Climate Access

Chapter 9Case Studiesbuildings have been structurally weakened by permafrost thaw adds tothe damage potential during any snow event (CSA, 2010).9.2.10.3. Description of Vulnerability9.2.10.3.1. Permafrost thawPermafrost thaw is one of the leading factors increasing climate-relatedvulnerability. Permafrost is by definition dependent on a sub-zerotemperature to maintain its state (CSA, 2010; NRCAN, 2011a). With achanging climate, it is difficult to predict where permafrost is most likelyto thaw, but about half of Canada’s permafrost zones are sensitive tosmall, short-term increases in temperature, compromising the ability ofthe ground to support infrastructure (Nielson, 2007; NRTEE, 2009; CSA,2010). The rate of thaw (and hence implications for infrastructure stability)is also dependent on soil type within the permafrost zone (Nielson,2007). Areas that have ice-rich soil are much more likely to be affectedthan those with a lower ice-soil ratio or those that are underlain bybedrock (Nelson et al., 2002). Municipalities in discontinuous or sporadicpermafrost zones may feel the impacts of a warming climate moreintensely since the permafrost is thinner than it would be in continuouszones where ice has built up over time (Nelson et al., 2002).Though some infrastructure maintenance will always be required, climaterelatedpermafrost thaw will increase the needs for infrastructuremaintenance and the rate of damage that is inflicted (Allard et al., 2002).Permafrost thaw affects different types of infrastructure in radicallydifferent ways. In northern Canada, municipalities have experiencedmany different climate-related impacts on physical infrastructureincluding the following (Infrastructure Canada, 2006; Nielson, 2007;NRTEE, 2009):• Nunavik, in northern Quebec, reported that local roads and airportrunways have suffered from severe erosion, heaving, buckling, andsplitting (Nielson, 2007; Fortier et al., 2011).• In Iqaluit, in Nunavut, 59 houses have required foundation repairand/or restoration and buildings with shallow foundation systemshave been identified as needing attention in the near future(Nielson, 2007). In Inuvik, in the Northwest Territories, a recentstudy estimated that 75% of the buildings in the municipalitywould experience structural damage (Bastedo, 2007) dependingon the rate of permafrost thaw.• The Tibbitt to Contwoyto winter road (Northwest Territories)experienced climate-related closures in 2006, remaining open foronly 42 days compared to 76 in 2005 (Bastedo, 2007). This resultedin residents and businesses having to airlift materials to theircommunities instead. In particular, the Diavik Diamond Mine wasforced to spend millions of dollars flying in materials (Bastedo,2007; Governments of Northwest Territories, Nunavut, and Yukon,2010).• The Northwest Territories reported that the airport runway inYellowknife required extensive retrofitting when the permafrostbelow it began to thaw (Infrastructure Canada, 2006).The impacts of permafrost thaw on infrastructure have implications forthe health, economic livelihood, and safety of northern Canadiancommunities. The costs of repairing and installing technologies to adaptto climate change in existing infrastructure can range from severalmillion to many billions of dollars, depending on the extent of thedamage and the type of infrastructure that is at risk (InfrastructureCanada, 2006). Lessons from municipalities in the United States haveproven that these costs can be large. For instance, while the Yukonhad financial difficulties with CDN$ 4,000 km -1 yr -1 costs related topermafrost damage to highways, Alaska is experiencing costs of up toCDN$ 30,000 km -1 yr -1 for an annual cost of over CDN$ 6 million overa 200-km stretch (Governments of Northwest Territories, Nunavut, andYukon, 2010). In the future, as infrastructure needs to be replaced, costswill multiply rapidly (Larsen et al., 2008).9.2.10.3.2. Snow loadingIn most northern Canadian communities, buildings and roadways arebuilt using historical snow load standards (Nielson, 2007; Auld, 2008).This makes them particularly vulnerable to climate change since snowloads are expected to increase with higher levels of winter precipitation(Christensen et al., 2007; NRTEE, 2009). Already in the NorthwestTerritories, 10% of public access buildings have been retrofitted since2004 to address critical structural malfunctions. An additional 12% ofbuildings are on high alert for snow load-related roof collapse (Auld etal., 2010). In Inuvik, NWT, a local school suffered a complete roof collapseunder a particularly heavy snowfall (Bastedo, 2007). As permafrostcontinues to thaw, resulting in a loss of overall structural integrity, greaterimpacts will be linked to the increase in snow loads as previouslyweakened or infirm structures topple under larger or heavier snowfalls.9.2.10.4. OutcomesIn response to these vulnerabilities, government and community leadershave put emphasis on action and preparedness (Government of NorthwestTerritories, 2008; Governments of Northwest Territories, Nunavut, andYukon, 2010). The social impacts of relocating communities or completerestoration after a major disaster, as well as the financial costs, providea strong deterrent to complacency and relocation will be utilized wherenecessary as a last resort (USARC, 2003). Though each government tier,from federal to municipal levels, tackles the issue from a different angle,their approaches are proving complementary as is demonstrated below.This section explores adaptation efforts from each level of governmentand the contribution they make to adaptive capacity in northernCanadian communities.9.2.10.4.1. Federal levelThe Canadian government contributes to numerous adaptation effortsat different levels and through various programs (Lemmen et al., 2008).515