Nat Hazards DOI 10.1007/s11069-017-2793-7

ORIGINAL PAPER

A multi-perspective examination of heat waves affecting Metro : now into the future

1 1 2 Ronald E. Stewart • Daniel Betancourt • James B. Davies • 3 3 2 Deborah Harford • Yaheli Klein • Robert Lannigan • 4 4 2 Linda Mortsch • Erin O’Connell • Kathy Tang • Paul H. Whitfield3

Received: 9 February 2016 / Accepted: 24 February 2017 Ó Springer Science+Business Media Dordrecht 2017

Abstract Using studies of places where heat waves are common, projected changes in heat waves in Metro Vancouver are assessed from a multi-disciplinary perspective with respect to the potential impacts of the physical change on the people and infrastructure with the intention of being better prepared for future events. Trends in maximum temperature parameters for Metro Vancouver for the past 75 years are generally not statistically sig- nificant; however, projections for 2041–2060 and 2081–2100 suggest that the region will experience such events more frequently in the future due to . While Metro Vancouver, (BC) generally does not typically experience heat waves it was strongly affected by a major heat event in July 2009, with temperature records being broken at Vancouver (C31 °C) on the coast and at Abbotsford (C36 °C) 65-km inland. A lack of sea breeze during this event meant that there was no cooling effect, and land surface temperatures over the downtown area approached 40 °C and excess deaths occurred. Many victims were either in the 65–74 age category, the vulnerable poor, or people with mental health issues. Because these events are rare, many buildings lack air-conditioning, and residents of Metro Vancouver under-anticipate their vulnerability. The costs of health- related impacts outweighed those related to higher electricity usage.

Keywords Heat waves Climate change Impacts Adaptation Preparedness Á Á Á Á

& Ronald E. Stewart [email protected]

1 University of Manitoba, Winnipeg, MB, 2 University of Western Ontario, , ON, Canada 3 Simon Fraser University, Burnaby, BC, Canada 4 University of Waterloo, Waterloo, ON, Canada

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1 Introduction

Urban climate change-related risks, including heat stress, are increasing in many regions of the world (Revi et al. 2014). Although there is some awareness of heat-related challenges in Metro Vancouver and a general sense that these may increase in the future, relatively little research has been conducted on this issue and much of what has been done is related to health effects associated with illness and mortality. The objective of this study is to examine heat waves in Metro Vancouver from a multi-disciplinary point of view spanning physical, health, social, economic, and adaptation perspectives. This paper summarizes the impacts of the 2009 , and using a literature review of vulnerability factors and heat wave impacts from other places suggests adaptation measures that might reduce the negative consequences of such events in the future. Smoyer-Tomic et al. (2003) argued that, since Canada has a cold climate, heat waves are not perceived as a serious threat. Metro Vancouver historically has not been subject to heat waves. Despite this perception of the region as being exempt from the risk of extreme heat, Metro Vancouver does periodically suffer from such events; the one which occurred in 2009 (Kosatsky 2010) had a two-day average of maximum temperatures reaching C31 °C at Vancouver International Airport (YVR) and C36 °C at Abbotsford International Airport (YXX) (Henderson and Kosatsky 2012). (These airport letter codes will be used in the rest of this article.) Although seemingly anomalous, this event is part of a measurable trend. In an IPCC assessment of observed and projected temperature extremes for western North America, Hewitson et al. (2014) reported large increases in observed hot days and warm nights (high confidence) and an increase in duration of warm spells (medium con- fidence). Similar patterns were revealed for future projections including warmer daytime and nighttime temperatures and more frequent, longer and/or more intense heat wave and warm spells (high confidence). In Canada, there is a warming trend in observed daily maximum and daily minimum temperature, while the number of cold events is declining (Bush et al. 2014). The frequency of warm summer days (i.e., daily maximum temperature exceeds the 90th percentile) has increased across most of Canada (Bush et al. 2014). Across southern BC, there has been an increase in extreme temperature represented by the (index combining air temperature and temperature); there has also been a significant increase in the number of nights during which the humidex remains at or above a threshold of 20, and[30 in a few locations. YVR has also recorded an increase in the number of days with extreme nighttime humidex, but no significant increase in the number of days over 30 for the period 1953–2012 (Mekis et al. 2015). Martin et al. (2011) analyzed three periods of future climate projections for 15 Canadian cities and concluded that Metro Vancouver will likely be subjected to increasing heat-related issues in the future (Fig. 1). Persistent high temperatures can lead to a range of negative impacts related to human health (Hajat et al. 2006; Kovats and Hajat 2008), quality of life, urban systems, infras- tructure assets, local and national economies, and ecosystems (Smoyer-Tomic et al. 2003). The risks are higher for people living in hazardous areas or where adaptation planning and the supportive infrastructure and services are lagging (Revi et al. 2014; Koppe et al. 2004). The associations between climate and health are complex and can be mediated through multiple factors such as location, socioeconomic status, age, preexisting health conditions, access to health care, the built and natural environments, and adaptation actions (Romero- Lankao et al. 2014). Vulnerable groups include infants, the elderly, the socially

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Fig. 1 Map showing the regional topography and population centers in the Metro Vancouver area. The locations of weather stations at Vancouver International Airport (YVR) and Abbotsford Airport (YXX) are highlighted disadvantaged, and people with disabilities and preexisting health conditions (Smith et al. 2014; Berry et al. 2014a). There is debate and confusion in the term ‘‘heat wave,’’ Prezerakos (1989) pointed out that there was not a precise definition and many research meteorologists use a loose definition that encompasses atmospheric blocking patterns and warm air advection. Smoyer-Tomic et al. (2003) compared absolute and relative measures and heat stress indices and explained that there are many ways to define heat wave indices for predicting impacts. Whitman et al. (1996) argued that an explicit definition was needed and it should be standardized and accepted by medical examiners and coroners. Changnon et al. (1996) found that heat waves exceed all other weather events in terms of average and extremes of numbers of deaths, and called for a standard, widely accepted definition of what constitutes a heat death. Environment Canada (2013) provides an absolute definition of a heat wave as more than three consecutive days with temperatures in excess of 32 °C. However, adverse effects have been noted at lower temperatures and during shorter duration events (Smoyer et al. 2000). In fact, locations with mild warm seasons have shown some of the largest increases in mortality due to extreme heat (Lemmen and Warren 2004). Smoyer-Tomic et al. (2003) suggested that relative approaches should therefore take local conditions of exposure and acclimatization into account. Although the 2009 Metro Vancouver event does not satisfy Environment Canada’s definition of a heat wave, it was a significant event due to the extreme temperatures, loss of life, and the region’s lack of adaptation to high heat conditions. Robinson (2001) proposed a generic definition for heat waves using the exceedance of an absolute value and the deviation from ‘‘normal’’ to better address local conditions and suggested that a heat wave be defined as: ‘‘A period of at least 48 h during which neither the overnight low nor the daytime heat index falls below the National Weather Service heat stress thresholds (26.7 °C and 40.6 °C).’’ We therefore use the term heat wave in this sense but with different thresholds in this article.

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One important motivation for this study was that a review of the institutional responses to the 2009 heat wave uncovered a lack of research into the physical, social, economic, and adaptation measures, as well as their integration. It is critical to develop a better understanding of the occurrence and spatial and temporal variation of Metro Vancouver heat waves. Heat waves illustrate some systematic patterns; but, there are also substantial differences, stemming in part from regional atmospheric circulations such as the sea breeze. Given the varying impacts that have been identified, it would be useful to relate the physical driving mechanisms to their consequences in order to better anticipate the need for actions during future events. The authors of this study are Canadian participants in the Coastal Cities at Risk Study (McBean ND), partnered with research teams in Manila, Philippines; Bangkok, Thailand; and Lagos, Nigeria. Over the past four years of this five-year international research project dedicated to the exploration and characterization of climate change risks and impacts on coastal mega-cities, it has become clear that, although the cities differ widely in their loca- tions, challenges, and approaches, there are many common factors. The physical, social, economic, and health impacts of events driven by climate change manifest in each city in many similar ways, with significant differences in both the capacity of the cities to respond and the priorities dictated by the conditions within each. In all four cities, extreme heat is a risk; however, ironically, it is the city located in the coldest climate, Metro Van- couver, which may face some of the biggest challenges with extreme heat due to regional unfamiliarity, and subsequent unpreparedness for, this emerging aspect of climate change. The balance of this paper is organized as follows: Sect. 2 examines the physical mechanisms governing the 2009 event, and the trends and changes in frequency of high temperature events over the past 75 years in Metro Vancouver; Sect. 3 summarizes the literature, provides specifics about the 2009 event for health, social, and economic issues, and compares this event with those in other cities; Sect. 4 examines the projections of future events and their likely impacts, and Sect. 5 describes possible adaptation options and/or measures; and Sect. 6 provides some concluding remarks.

2 High temperatures in Metro Vancouver

The climate of Vancouver is characterized as Pacific maritime, with average July maxi- mum temperatures of 21 °C near the coast at YVR, and 23 °C approximately 65-km inland at YXX. The adjacent cool ocean typically provides a moderating effect that limits large diurnal temperature fluctuations. Consequently, the implications of high temperatures have largely not been integrated into the planning and implementation of the region’s urban form and infrastructure. The general distribution of heat waves in Canada was discussed by Smoyer-Tomic et al. (2003), who suggest that heat waves in Canada are more prevalent in the east (Ontario and Quebec) and that the effects are minimal in the north, Pacific, and Maritimes. Bellisario et al. (2001) reviewed extreme events in the Greater area and reported heat wave events in 1912, 1921, 1953, 1963, 1973, 1981, 1987, and 1988. The longest duration was in 1953 and extended for 13 days—much more intense than the 2009 Metro Vancouver event. Heat waves in the USA have been studied extensively and also tend to be more dramatic. Golden et al. (2008) reported on the 2003 Phoenix heat wave, which reached record-high minimum temperatures of 35.5 °C. In a 6-year study of heat-related dis- patches, Golden et al. (2008) found that most occurred during periods of maximum tem- perature and . In 1995, a heat wave with high heat and humidity in resulted in 700 excess deaths (Semenza et al. 1996). Karl and Knight (1997) reported that

123 Nat Hazards this event was unusual, with high apparent temperatures, a return period of B23 years, and most notably an unprecedented persistence of temperatures in excess of 31.5 °C for more than two days. Whitman et al. (1996) reported 485 heat-related and 696 total excess deaths during this event and showed that the apparent and actual temperatures peaked at the same time, with humidity contributing 15 °F (104–119 °F; 40.0–48.3 °C). Changnon et al. (1996) reported 525 deaths in Chicago and 830 in the USA for the same event and implicated power failures and poor preparation. Hoerling et al. (2013), reporting on the 2011 Texas /heat wave, identified the main cause as a severe rainfall deficit during antecedent and concurrent seasons and suggested that human-induced climate change doubled the probability of the event to about 6%. Heat waves studies from other regions are also informative. Black et al. (2006) reviewed meteorological aspects of the showing that the extreme tem- peratures and lack of were related to persistent anticyclonic conditions that caused an increasingly dry land surface. Fennessy and Kinter (2011) assessed the climatic feedbacks of this event using an ensemble of models and found that anomalously dry soil combined with lower than normal precipitation intensified the heat wave. Last (2010) reported that premature deaths numbered between 35,000 and 50,000 persons during this event. Tong et al. (2010) reported on the 2004 Brisbane, , heat wave, which reached a temperature of 42 °C compared to 34 °C in the same period in the previous three years. The excess death total was 111, attributed mainly to temperature; however, elevated ozone levels were also implicated.

2.1 The development of the 2009 heat wave

The July 28–30, 2009, heat wave was characterized by a highly amplified upper flow with a prominent upper ridge over the of British Columbia (red in Fig. 2a, and [1022 hPa in Fig. 2b). This pattern is typical of such events in the region (Bumbaco et al. 2013). At a wider scale, the meridional pattern at 500 hPa was characterized by upper lows near the Aleutian Islands and Hudson Bay. At the surface, a thermally induced trough

Fig. 2 Composite maps of a 500 hPa geopotential height (m) and b sea-level pressure (hPa) for July 28–30, 2009

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(Brewer et al. 2012, 2013) extended northward near the coast from the southwestern USA. This trough marked the separation of two high pressure areas, one representing a northward extension of the Pacific or Hawaiian High and the other a ridge extending down from a high pressure center situated in the Beaufort Sea. The trough extended northward toward Metro Vancouver through the course of the heat wave. The pressure gradient was generally weak, but a downslope and offshore flow occurred on the eastern side of the trough. This feature eventually weakened and shifted southeast. There is typically an afternoon shift to westerly winds at YVR as an onshore sea breeze is established (Steyn and Faulkner 1986), which occurred on the first two days of the heat wave (July 28–29). As the trough moved eastward, a local offshore flow was generated at YVR on the last day (July 30). The result was a reduction in marine-cooled air moving in from the Georgia Strait, allowing afternoon temperatures to reach extreme values. Meanwhile, the arrival of the sea breeze at YXX (identified by a southwest wind direction) occurred earlier on the final day due to the shifting surface pressure pattern. The result was that the maximum temperature was suppressed somewhat at the Abbotsford station on July 30. The resulting temperatures over the region broke records on July 29 at YVR (34 °C) and at YXX (38 °C) (Fig. 3a). The subsequent day’s temperatures were even higher at YVR (34.4 °C) with the local offshore effect. An important aspect of this heat wave was that nighttime temperatures and humidity were also high with minimum temperatures on July 30 being *24 °Catbothlocations.Dewpoint

Fig. 3 a Temperature, b humidex, and c wind speed and direction (arrows indicate the compass direction to which the air flow is directed) at Vancouver International Airport (YVR) (dashed line) and Abbotsford International Airport (YXX) (solid line) for July 28–30, 2009. Pacific daylight time (PDT) is used

123 Nat Hazards temperatures exceeded 18.5 °CatYVRand19 °CatYXXonJuly29.Suchvaluesareunusualfor this region. The combination of high temperature and high dew point led to high daytime humidex values (Fig. 3b), reaching 37 at YVR and 44 at YXX. The high nighttime humidex values of 30–31 at both locations are similar to eastern Canadian heat waves (Mekis et al. 2015). Information from these two weather stations, which are separated by approximately 65 km, does not fully represent the spatial variations in temperature across the region. Surface air temperatures were estimated from radiance values collected by the Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM ?) sensors. The satellite overpass nearest in time was used (1850 UTC (1150 PDT) on July 31, 2009, Fig. 4). Land surface temperature exhibited in Fig. 4 shows considerable spatial structure with values above 35.1 °C in many areas. High-density downtown areas dominated by commercial and industrial buildings, apartment buildings, and large areas of pavement absorb and retain heat. Urban areas can have much higher daytime and nighttime temperatures ([10 °C) than rural areas. Ho et al. (2014) has similar results from a spatial regression approach combining weather station data with Landsat image retrievals from five different summers in Metro Vancouver. YVR reports much lower temperatures than those experienced farther inland, and this is also evident in Fig. 4.

2.2 Heat wave trends in Metro Vancouver

Trends in the number of days temperatures that exceeded a series of temperature thresholds in Vancouver were analyzed. Only two locations (YVR and YXX (Fig. 1)haveobservationrecords of sufficient duration for examination (1937–2013 and 1945–2014, respectively). Trends in the number of days and events per year and the duration of the longest annual event at or above specific temperature thresholds (i.e., above 26, 27…°C) were determined using logistic regression since the data are counts of threshold exceedances. The nonparametric Mann–Kendall was used to test for trends in the mean duration of events above temperature thresholds. The results from these tests are shown in Table 1.Inlogisticregression,oddsratiosrepresentthechangein

Fig. 4 Estimated land surface temperature from Landsat thermal band information at July 31, 2009, 18:50:31.896 UTC. The image spatial resolution is 30 m

123 123 Table 1 Results of trend tests for different temperature thresholds for Vancouver (YVR) and Abbotsford (YXX) Days per year Events per year Longest events per year Average length of events

Logistic regression Logistic regression Logistic regression Mann–Kendall

Odds ratio Probability Over- Odds ratio Probability Over- Odds ratio Probability Over- Kendall- Probability dispersion dispersion dispersion Tau

YVR [26 1.42 0.280 3.90 1.32 0.279 1.45 1.30 0.293 0.95 0.02 0.844 [27 1.52 0.264 2.79 1.10 0.742 1.18 1.83 0.048 0.91 0.12 0.139 [28 1.20 0.696 2.17 1.04 0.934 1.32 1.52 0.299 1.01 0.04 0.669 [29 1.03 0.968 1.89 0.97 0.970 1.48 1.75 0.521 1.23 0.02 0.852 [30 1.97 0.530 1.92 1.57 0.650 1.26 2.58 0.361 1.39 0.07 0.433 [31 4.47 0.330 1.43 4.44 0.296 0.92 4.41 0.330 1.43 0.10 0.292 [32 23.34 0.384 1.40 4.57 0.559 1.02 23.34 0.284 1.40 0.06 0.543 YXX [26 1.437 0.033 4.001 1.109 0.381 0.872 1.378 0.175 1.699 0.152 0.064 [27 1.561 0.018 3.747 1.188 0.203 0.944 1.398 0.182 1.529 0.181 0.028 [28 1.694 0.012 3.553 1.467 0.026 1.191 1.207 0.540 1.803 0.110 0.181 [29 1.911 0.008 3.307 1.760 0.005 1.183 1.518 0.161 1.178 0.085 0.310 [30 1.485 0.163 3.497 1.419 0.149 1.407 1.349 0.341 1.087 0.085 0.311 [31 1.523 0.196 2.968 1.292 0.372 1.359 1.871 0.047 0.839 0.183 0.032 [32 1.760 0.142 2.436 1.534 0.250 1.386 1.910 0.069 0.768 0.139 0.113 [33 2.167 0.070 1.688 2.116 0.069 0.939 2.728 0.018 0.750 0.179 0.047 [34 1.397 0.566 1.650 1.469 0.460 0.863 2.029 0.169 0.775 0.105 0.261 [35 0.980 0.980 1.601 1.052 0.946 0.942 1.079 0.918 0.941 -0.013 0.894 a Hazards Nat [36 1.436 0.674 1.187 2.385 0.305 0.817 2.385 0.305 0.817 0.098 0.317 [37 4.585 0.298 0.965 16.486 0.130 1.000 16.49 0.130 1.000 0.166 0.096 Values that are statistically significant are bold and underlined Nat Hazards odds for the dependent variable per unit of the independent variable: Odds ratios[1indicatea positive trend and those\1indicateanegativetrend. In most cases, the odds ratios at YVR were positive, which indicates increases in the frequency and duration of events above thresholds. However, only the maximum duration of events greater than 27 °C was significant. Despite the lack of statistically significant trends, the values of Kendall-Tau and the odds ratio both indicate increases in frequency and duration of these events. The magnitude of the odds ratio increases with the magnitude of the threshold, suggesting that the highest temperatures are increasing the most. We found positive increases for almost all variables at YXX (Table 1). Results are most robust for the occurrence of lower temperature threshold events (26–29 °C), with all values found to be significant. In terms of average and maximum duration, most increases were not statistically significant, possibly due to the rarity of the most extreme events and the small sample size. It is also interesting that there are more significant trends at YXX at lower thresholds (26–29 °C); unlike YVR, this location is relatively shielded from the sea breeze. The year 2009 stands out as the year with the highest temperatures in the Metro Vancouver area. American studies such as Bumbaco et al. (2013) report that the increasing frequency of high minimum temperature events is the only significant trend with respect to Pacific Northwest heat waves. The 2009 event was measurable across the USA as well; all- time record maximum temperatures were set in many locations, including both the second strongest daytime and longest nighttime events ever recorded. In western and , the 2009 event is the only event in the record with eight consecutive days above the 99th-percentile threshold of minimum daily temperature in the Pacific Northwest (Bumbaco et al. 2013).

3 Impacts of heat waves

Projecting what the impacts of future heat waves in Metro Vancouver depends upon information from cities and locations where heat waves occur frequently. The literature was used to understand the range of human health, social, and economic issues that could be expected, and these findings have then been associated with the 2009 Vancouver event.

3.1 Health issues

Responses of people to high temperatures have been categorized into heat-related disease states that progress in severity, as follows: heat stress, heat exhaustion, and . These conditions usually include some combination of intense thirst, weakness, muscle cramps, anxiety, dizziness, fainting, and headache. Heat stroke is a severe illness diag- nosed by a rise in core body temperature above 40 °C with central nervous system abnormalities such as delirium, convulsions, or coma. Heat stroke that is not treated immediately can result in multi-organ dysfunction and failure that leads to death (Health Canada 2011a). A key aspect of the problem is that too few people are diagnosed with heat-related symptoms as the symptoms are quite variable in presentation, and only extreme cases might be correctly reported so medical records will not reflect the entire range of people suffering effects. This makes gathering retrospective information on historic heat wave events and determining the extent of heat-related illness associated with them, difficult.

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There is less variability in terms of death related to heat stroke, and this is what is usually reported; however, the full extent of heat-related illness during a heat wave is considered to be underreported (Rodriguez et al. 2007). What is clear is that early intervention to reverse these conditions has the greatest success and that a high degree of awareness of heat- related illnesses on the part of all clinicians who attend patients would be beneficial. A number of factors that help to identify those who are likely to experience health impacts during an extreme heat event. These need to be understood within the socially constructed nature of vulnerability (Browning et al. 2006) to extreme heat events, which is unevenly distributed among different segments of society (Jonsson and Lundgren 2015). In the USA, people over 65 and older were over-represented and Hispanic people under- represented in studies by Whitman et al. (1996) and Changnon et al. (1996). Age has been an inconsistent vulnerability characteristic in other heat wave events; for instance, Berry et al. (2014a) found that the very young (aged 0–5) did not experience higher heat-health impacts compared to the general population; however, another study found an association between maximum daily temperatures of 29 °C or more and increased likelihood of sudden infant death syndrome (SIDS) (Auger et al. 2015; Smoyer-Tomic and Rainham 2001) showed that excess deaths were largely confined to people older than 64. Risks were higher for people with known medical conditions or who were confined to bed, living alone, and/ or on the top floor of a building, but were reduced for people with air-conditioning or access to transportation, or who own a pet (Semenza et al. 1996). The physical conditions of housing and residences are likely to have an impact; living on an upper floor and poor ventilation were linked to higher mortality and morbidity after ’s 2003 heat wave (Nitschke et al. 2013). At the individual level, the elderly have been identified as a key vulnerable group due to potential physiological impairments including reduced cognitive ability and mobility, reduced thirst sensation, variability in fitness levels, and ability to sweat, as well as sus- ceptibility to dehydration (Kenny et al. 2010). There are a number of chronic and preex- isting medical conditions that also predispose individuals to heat-related illness: Most of these are related to heart or lung conditions (Lesnikowski 2010), but individuals with chronic kidney disease and mental illness are also vulnerable. Certain classes of medica- tions also exacerbate vulnerability, such as diuretics, high blood pressure medication, and psychiatric disorders. Individuals of lower socioeconomic standing may be more vulner- able due to lower access to air-conditioning and swimming and cooling refuges (Health Canada 2011a; Miller 2014). People who are socially isolated and marginalized, particu- larly those with cumulative health conditions (e.g., someone who is elderly and suffering from a preexisting health condition), are also more vulnerable (Browning et al. 2006); likewise, individuals requiring bed confinement or those who have weakened immune systems, pregnant women, overweight individuals, those working outdoors, and those without air conditioners at home may be at elevated risk (Dotto et al. 2010; McBean et al. 2007). This suggests that it is important to understand the influencing factors, so that ‘‘individuals and communities can protect those most vulnerable to [suffering] extreme heat impacts,’’ both at the individual and community level (Health Canada 2011a, b). There is often variability of heat-health impacts within vulnerable groups; vulnerability is not uniform (Jonsson and Lundgren 2015). A review of emergency room visits and hospitalization rates in Canada found that marginalized populations (e.g., the homeless), recent immigrants, and the very young (aged 0–5) did not experience higher heat-health impacts compared to the general population (Berry et al. 2014a). Xu et al. (2014) found inconsistent results related to the impact of extreme heat on children, although they did find higher mortality rates in infants. Wolf et al. (2010) found mixed evidence related to the

123 Nat Hazards role of social capital in reducing vulnerability; for instance, bonding within social networks may actually encourage, rather than correct, faulty risk perceptions under which vulnerable individuals view themselves as misleadingly capable of responding to and coping with extreme heat. Thus, there is a need for clear understanding of the specific vulnerability characteristics relevant for each community in order to effectively plan for, and reduce vulnerability to, heat waves. The 2009 Vancouver heat wave was linked with elevated mortality in Metro Vancouver (Henderson and Kosatsky 2012). Estimates ranged from 122 to 156 excess deaths (Van- couver Coastal Health 2011; Kosatsky 2010) and increased numbers of emergency room visits. There were 398 non-accidental deaths recorded during the period of July 27–August 2, 2015, compared to an average of 290 weekly deaths during the summer months (June, July, and August) from 2001 to 2009 (Kosatsky et al. 2012). Only 1% of the 398 recorded deaths were formally documented as being due to heat, but BCCDC attributes 72 excess deaths to the heat wave (BCCDC, personal communication 2015); this is a higher pro- portion attributed to heat and respiratory causes than at any other time during 2001–2008 (Kosatsky et al. 2012).There is limited information on other health impacts beyond cate- gories of excess mortality causes during the 2009 heat wave. The results for Vancouver are similar to those reported in these other studies.

3.2 Social issues

Although much research has focused on the immediate health impacts of extreme heat, there are social impacts that extend beyond health concerns. For example, the ‘‘heat hypothesis’’ suggests that uncomfortably warm temperatures increase aggressive and violent behavior (Anderson and Anderson 1996). This hypothesis has been highlighted in numerous studies that suggest that increases in temperature are correlated with a higher incidence of crimes such as rape, murder, riots, and assaults (Smoyer-Tomic et al. 2003). A study conducted after heat events in , Canada, found increases in reported assaults and domestic violence (Ouimet and Blais, 2001). Further, extreme heat can exacerbate marginalization and social isolation; Miller (2014, p 2) notes that vulnerable individuals tend to remain indoors, and ‘‘visits by friends, neighbors, and family, the delivery of social services, such as home and community care (HACC), and the organization of social outings for the elderly, frail and disabled may be reduced or canceled, further exacerbating the experience of isolation.’’ While preexisting health concerns have been cited as a vulnerability (Lesnikowski 2010), there is relatively little information on the role of mental health. Preliminary data (BCCDC, personal communication 2015) indicate that 18 deaths during the extreme hot weather event were attributed to self-harm or accidental overdoses; these numbers are significantly higher than expected for the region during a 1-week period. These are some of the more important aspects to consider within the health-related impacts. Behavioral responses to extreme heat may also affect vulnerability. Mitigation is strongly lined to risk perception; in a study in Phoenix, Arizona, those who perceived extreme heat as a greater risk were more likely to modify their behavior after a heat warning (Kalkstein and Sheridan 2007). Response to a warning is linked to a number of factors, including trust in authorizing agencies, age, and ethnicity (e.g., older people and certain ethnicities were more likely to respond to the warning) (Kalkstein and Sheridan 2007). Nitschke et al. (2013) reported the contrary; the majority of elderly individuals they sampled did not consider themselves vulnerable to extreme heat events, even if they suffered from preexisting illnesses or were taking medications recognized as heightening

123 Nat Hazards susceptibility to heat-health impacts. High-vulnerability groups may overlook their own risk factors and engage in unknowingly harmful behaviors, or rely on previous experiences in warmer climates (Sampson et al. 2013); risk perception could be an important influence on the variability of impacts experienced among vulnerable populations. Although there is limited research on risk perception in Metro Vancouver, the 2009 heat wave was unprecedented, suggesting the risk may have been perceived as low. Acclimatization also has an impact on vulnerability to extreme heat. For example, events occurring early in the summer tend to result in greater mortality and morbidity due to the lack of gradual acclimatization to warmer temperatures (Health Canada 2011a). The Metro Vancouver data suggest that certain groups experienced higher impacts than others during the 2009 heat wave. In a departure from other research that has found the most elderly to be the most vulnerable (Kenny et al. 2010), risk of mortality was found to be highest in the 65–74 age category, even compared with those aged 85 and older. Inter- estingly, there was also an increase in the proportion of deaths occurring at home and a decrease in the proportion of those occurring in hospitals and care facilities (Kosatsky et al. 2012). Elevated risk of mortality in disadvantaged and more densely populated areas in Metro Vancouver suggests that low income and deprivation also played a role during the heat wave, as pointed out by Kosatsky et al. (2012). As we have noted, individuals of lower socioeconomic standing may experience higher levels of vulnerability (Health Canada 2011a; Miller 2014). Furthermore, the correlation between population density and risk of mortality during the 2009 heat wave confirms research, suggesting that physical and environmental factors influence the severity of extreme temperature event impacts; for instance, urban areas are likely to experience higher temperatures due to the effect, suggesting that urbanites are at greater risk than people in rural areas (Dotto et al. 2010). Higher temperatures and increased sunlight exposure also influence air quality, resulting in increased levels of lower atmospheric ozone, also known as smog, which can exacerbate heat-health impacts (Lesnikowski 2010). The current relative lack of air-conditioning due to the temperate climate in Metro Vancouver and in BC generally is striking. In 2011, only 575,537 households, or 31% of the total, had air-conditioning, compared with four out of every five households in Ontario (see Natural Resources Canada (2014) Table 1.1 and 7.1), although most of these devices are concentrated in the warmer interior regions (Proctor 2011) and therefore are even less common in Metro. Additionally, high-rise buildings are often designed with windows that cannot open wide, or at all, to ensure safety. This suggests that lower rates of acclimati- zation to extreme heat are a significant vulnerability factor and are exacerbated by infrastructure-related factors. Analysis of the social vulnerability considerations of the 2009 heat wave in Metro Vancouver reveals several distinct features. As we noted above, although the elderly have generally been identified as the most vulnerable, the experience in Metro Vancouver suggested that the 65–74 age range experienced the highest mortality. A number of other vulnerability factors noted during the Metro Vancouver heat wave were similar to those recorded during other heat events in North America and , including population density, associated urban heat island impacts, and the possible roles of poverty, depriva- tion, and marginalization. Mental health concerns may have been a significant factor impacting risk of mortality in Metro Vancouver. Although underlying health conditions are often highlighted as vulnerabilities, the role of mental health is less clear, suggesting that further research in this area would be useful. Acclimatization is particularly relevant for Metro Vancouver, as residents are less used to higher temperatures (specifically 30 °C and above); for the period 1961–1991, there are

123 Nat Hazards no observed occurrences of these ‘‘hot days’’ (Berry 2008; City of Vancouver, 2012) and thus residents are likely to experience impacts at lower temperatures (Chuang 2013). Mortality thresholds related to temperature during the 2009 heat wave were significantly lower compared with those in warmer climates (e.g., cities in the southern USA and interior regions in Canada) (Kostasky et al. 2012). These findings again emphasize the importance of considering contextual factors when determining future thresholds for heat advisories and response systems in Metro Vancouver. Further information on the role of social capital is also required. The evidence from Metro Vancouver suggests a shift in patterns of population mortality for those living at home compared with institutions during the extreme heat event; it would be informative to understand whether this had any association with social capital and/or living situation. Although a lack of social capital was found to increase vulnerability in some heat waves (e.g., Europe in 2003), other evidence is mixed. Wolf et al. (2010) found that social capital may even have increased vulnerability; bonding social networks may perpetuate, rather than ameliorate, risk perception narratives whereby vulnerable individuals view them- selves as overly capable of responding to and coping with extreme heat events. Given that overall perception and awareness of heat wave risks are generally low in Metro Vancouver, the role of social capital may have contributed to increased vulnerability. Overall, the observed vulnerability to extreme heat findings in Metro Vancouver suggests that there is a need for clear understanding of the specific vulnerability characteristics particular to each community in order to effectively plan for, and reduce vulnerability to, extreme heat events.

3.3 Economic impact

Heat waves can have a wide range of direct and indirect economic impacts, particularly where conditions exceed design specifications. Infrastructure such as roads and bridges experiences increased expansion and contraction resulting in rutting and cracking, increasing maintenance costs, and increasing the risk of accidents (Smoyer-Tomic et al. 2003). Railroad track expansion increases the risk of train derailments. Demand for electricity to power air conditioners during extreme heat events can also increase pressure on electrical infrastructure (Dotto et al. 2010) and can result in blackouts (Smoyer-Tomic et al. 2003). High temperatures directly affect electrical transmission including reduced efficiency (Smoyer-Tomic et al. 2003). Heat waves often include unexpected economic impacts, e.g., on a 2006 heat wave the per-kilowatt cost of generating electricity in nuclear plants in went up significantly (Pechan and Eisenack 2014). In Metro Vancouver, most residences and businesses lack air-conditioning; the general level of economic activity may decrease during a heat wave, as consumers spend less and devote more time to leisure activities, or because firms reduce output. It is unlikely that this loss would be fully compensated following the event. The economic costs of health impacts, the cost of additional electricity, and reduced economic output of the 2009 event were estimated using standard economic methods. A simple approach based on information that does not require extensive detail about popu- lation structure, social, and economic structure was chosen since these are not knowable in the future time periods. The health costs of heat waves have rarely been explicitly esti- mated, although there are exceptions (see, e.g., Alberini and Chiabai 2007); however, one indication is the value of a statistical life in current US studies of extreme weather events, which ranges from about $5 to $10 million (Simmons and Sutter 2011). The 2009 heat wave caused 72 excess deaths with an average age of 66. Assuming that a full life was

123 Nat Hazards worth $5 million, the value of life lost was calculated using the fraction of the mean full lifetime in BC in 2009 (82.3 years), lost by the representative decedents in 10-year age ranges. With 15 years of remaining expected lifetime on average lost, individual cost was $915,000; for the 72 lives lost the estimate was $65.9 million. While there is some uncertainty in this estimate, and other health costs were not included; it makes health the largest of all the costs of the heat wave. To estimate the impact on power supplies, electricity usage across BC during July 2009 was examined (Fig. 5). Electricity consumption increased significantly during the event and ‘‘saturated’’ at approximately 7100 MW. Increased use of energy for cooling is also reflected in the annual statistics shown in Table 2. This maximum level occurred when the temperature at YVR was approximately 29 °C; presumably because all available air- conditioning units were operating. These data are not broken down by region within the province, but since Metro Vancouver houses by far the largest portion of the population it allows estimation of the heat wave effect. Electricity usage during the event averaged about 500,000 kWh more than in the two prior weeks, which experienced normal tem- peratures. The estimated additional electricity output due to the heat wave was therefore about 48 million kW (12 million kW per day for the four days of the event). The current average cost of BC’s electricity is about $0.09 per kWh, calculated using total cost and output data in BC Hydro (2014), so the additional power would have cost about $4.3 million. From an overall social viewpoint, the cost would be smaller since when the system was operating below peak capacity, it should be evaluated at marginal rather than average cost. Peak output was 7.1 MW during the heat wave, while capacity was 12 MW according to BC Hydro (2015b). Marginal cost is low in BC because over 95% of its electricity comes from hydropower (BC Hydro 2015a). Most of the $4.3 million cost to residents then simply represents a transfer to BC Hydro, which in the long run may benefit its customers or BC

Fig. 5 Electricity usage (kWh) across British Columbia and Vancouver International Airport (YVR) hourly temperature (°C) during July 2009

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Table 2 Total space cooling energy use (PJ), British Columbia, 1990–2012 Adapted from Natural Resources Canada (2015) 1990 2007 2008 2009 2010 2011 2012

Residential 0.1 0.6 0.7 1.2 0.8 0.4 0.8 Commercial/institutional 1.3 2.5 2.8 4.7 2.9 1.5 2.8 (The commercial/institutional numbers are for British Columbia as well as the Yukon, Northwest Territo- ries, and Nunavut) taxpayers. The $4.3 million figure may thus be an upper bound on the true social cost of the extra electricity used during the heat wave. Estimating the cost of reduced economic output is challenging. The estimated total GDP for the Vancouver census metropolitan area (CMA), which is approximately Metro Van- couver, was $103 billion in 2009 (Brown and Rispoli 2014). Over a four-day period, each percentage point reduction in GDP would inflict an output loss of about $10 million; hence, if daily GDP losses were conservatively estimated at 5% the total output loss would be $50 million. The total cost of the 2009 heat wave could then be estimated at about $120 million, adding output loss to health and electricity costs of $66 million and $4 million, respectively.

4 Future heat waves

The physical and economic aspects of future heat wave lend themselves to analysis of projections based upon climate models and based upon the observations from the 2009 event. This simple approach was chosen since the physical aspects of this type of extreme will not be captured in any GCM or RCM since the event depends upon processes that are not captured in those models. Using some simple assumptions, we can project some economic costs based on the changes projected. This is not the case for health and social impacts which will only be considered from the perspective of adapting to future conditions.

4.1 Future projections of heat waves

An analysis of Coupled Model Intercomparison Project Phase 5 (CMIP 5) information (Taylor et al. 2012) was carried out to provide projections/scenarios of future heat wave occurrence in Metro Vancouver. The maximum and minimum temperatures of a future event similar to the 2009 heat wave are shown in Fig. 6; here the observed temporal pattern of the 2009 temperature series is adjusted for the differences in cumulative distribution functions for maximum and minimum temperatures between the historic period [1981–2000] and future periods [2041–2060 and 2081–2100] (delta method), forced by two Representative Concentration Pathways [RCP 4.5 (lower midrange forcing) and RCP 8.5 (high forcing)] (Moss et al. 2010) using output from the CSIRO Global Climate Model (GCM). Results from the BCC GCM were nearly identical. The GCMs used were selected based on their general performance on a global basis rather than any regional performance; any of the CMIP5 models could have been used.

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Fig. 6 Extrapolation of the 2009 Vancouver heat wave showing maximum and minimum temperatures observed at Vancouver International Airport (YVR) and modeled future maximum and minimum temperatures using the CISRO GCM and two representative concentration pathways (RCP 4.5 and 8.5) at two future periods (2041–2060 and 2081–2100). In the right margin are the mean differences between the observed series and the future projections

A comparison of the CSIRO model results in Fig. 6 with those of the BCC model (not shown) found that although the CSIRO warms more slowly than the BCC it reaches a higher level. The projections in Fig. 6 utilize observations from YVR, which do not include urban heat island effects (?1–3 °C warmer) occurring inland, nor the large shift in diurnal pattern in which evening temperatures can reach up to 12 °C warmer than their equivalent during cooler periods. Despite variations between the projections, they nonetheless give the same overall result: Heat waves such as the one that occurred in 2009 are expected to become more common in Metro Vancouver. It is recognized that the occurrence of extreme temperatures ([30 °C) in Vancouver is influenced by a range of factors, such as the modulation of temperature by the sea breeze, by offshore and down- slope flows, by synoptic and possibly sea surface temperature (SST) patterns, and these merit further study to improve heat wave projections (see, for example, Brewer and Mass 2016a, b). Models of the future occurrence of heat waves around the globe (e.g., Hunt 2007), all had negative precipitation anomalies prior to the event, reduced rainfall, soil moisture, evaporation, and cloud cover and increased insolation at the surface (Hunt 2007). Models of future wet-bulb globe temperature (Willett and Sherwood 2012) show regional depar- tures from the global average with significant observed and expected trends in the US Northwest for 28 °C and 32 °C. Martin et al. (2011) modeled temperature-related mortality in 15 Canadian cities for 2040, 2060, and 2080 using output from the Canadian Regional Climate model (CRCM4) forced by the A2 GHG emission scenario. While cold remains the greatest mortality risk to Canadians, higher temperatures were projected to increase mortality in Hamilton, London, Montreal, and Regina as well as Vancouver, where they

123 Nat Hazards projected annual average increases of 2.25 (2040), 3.51 (2060), and 6.71 (2080) deaths per 100,000 persons due to heat.

4.2 Economic implications of future heat waves in Metro Vancouver

The main economic impacts of the 2009 heat wave identified were health, electricity, and lost output costs. There are no doubt special factors affecting each of these costs, but there are also common factors to consider in the future. The population of Metro Vancouver is expected to rise strongly in coming years, which will magnify each of these costs. BC Stats (2015) projects that, from 2015–2040, the population of Metro Vancouver will rise by 870,252, from 2,506,974 to 3,377,266—an increase of 34.7%. Heat waves are likely to become more severe, tending to increase air-conditioning costs, health impacts, and output losses, although increased use of air-conditioning should partially offset the latter two. There are at least two special factors affecting the future air-conditioning costs of heat waves. The incidence of homes and other buildings equipped with air-conditioning is on the rise; this trend, which may be expected to continue, is reflected in the statistics of space cooling energy use in BC shown in Table 2. In 1990, the amount of energy used for cooling was 0.1 petajoules (PJ, 1015 joules) in the residential sector and 1.3 PJ in the commercial/institutional sector, for a total of 1.4 PJ. By 2012, the amounts had gone up to 0.8 PJ and 2.8 PJ in the residential and commercial/institutional sectors, respectively, for a total of 3.6 PJ. The more the homes that have air-conditioning, the greater will be the cost of electricity use during future heat waves. The other special factor affecting air-conditioning costs is that the true social marginal cost of electricity may rise in the future. Most of BC’s electricity comes from hydropower. In summer, the system operates below capacity and additional electricity can be generated at little cost. Due to population growth, it is expected that electricity demand will increase strongly in the coming years, which may alter the situation by leading to greater reliance on non-hydro generation and therefore to a higher marginal cost of electricity. BC’s electricity needs are projected to increase by 20–40% over the next 20 years due to industrial activity, general economic growth, and electrification (BC Hydro 2012). The provincial forecast indicates a 1.7% annual average growth rate in domestic electricity demand over the next 20 years, primarily through growth in population and economic activity, which is equiv- alent to a 40% increase in electricity requirements after 20 years. The projected require- ments include both customers’ annual energy demand (the amount of energy used in a year) and peak demand (the amount demanded from the system at any given hour) (BC Hydro 2012). Finally, as economic growth proceeds, the cost of lost output due to a heat wave would also rise, assuming other factors remain constant. We may project about 2% annual per capita economic growth in Metro Vancouver (the approximate mean per capita growth rate of the Canadian economy in the three decades before the global financial crisis of 2007–2008) over the next 25 years, which cumulates in a 64% rise in per capita output. Taking into account the BC Stats (2015) projection for Metro Vancouver population growth over this period of 34.7%, total output may approximately double. This would mean that, rather than causing a $50 million loss of output, a 5% [1%] drop in GDP for four days due to a heat wave would cause a $100 [$20] million loss, which would be magnified if the length of the heat wave increased.

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5 Adaptation options to extreme heat and heat waves

Adaptation is ‘‘the process of adjustment to actual or expected climate and its effects.’’ In human systems, adaptation seeks to moderate or avoid harm or exploit beneficial oppor- tunities. In some natural systems, human intervention may facilitate adjustment to expected climate and its effects (IPCC 2014, 1758). Fouillet et al. (2008) demonstrated that adap- tation and improved preparation can greatly reduce the impacts of heat waves on human health. Because of the 2009 event, there is regional recognition that action must be taken; however, Metro Vancouver has limited experience with extreme heat from which to understand the potential unique local implications of warming and hence develop adap- tations. Drawing from selected literature on adaptation to high temperatures and heat waves potential adaptations is identified for Metro Vancouver. These highlight examples where future research would be beneficial to local, regional, or provincial adaptation planning. The cities of Toronto and Montreal have developed public heat-health responses that have evolved over time and offer insights into vulnerable populations, development of alert thresholds, emergency response implementation, and associated partners and net- works (Kosatsky et al. 2005). Adaptation, or responding to the impacts of a changing climate, will be important as warming and associated changes intensify in the future. Adaptation to extreme temperatures and heat waves can be directed at multiple scales of response—individual, community, and region—in order to address the unique conditions of vulnerability, risk, and impacts (Smith et al. 2014; Berry et al. 2014b). An adaptation can target vulnerable populations who are likely to directly suffer from acute heat-related effects with measures that can be implemented prior to or during an event. Other adap- tations can be long-term, systemic, community-based changes leading to transformations in land use, urban planning, housing stock, economic activities, and energy use that influence health and quality of life during high temperatures (Harlan and Ruddell 2011; Carter et al. 2015). Given the wide range of vulnerable individuals, the breadth of responses to treatment, and the potential for sub-optimal outcomes, it is generally agreed that prevention is the best strategy. The most common action has been to develop and implement heat alert and response systems (Smith et al. 2014; Berry et al. 2014b; Harlan and Ruddell 2011). Implementation of these systems should be coordinated among public health organizations, municipal, emergency and weather forecasting services, and media outlets and include relevant non-governmental organizations (Koppe et al. 2004). Other preventative options including coordinated education and awareness programs, provision of air-conditioned refuges, and free transportation to cooling centers extended hours of public pools and use of existing organizations and networks (e.g., churches, mail carriers) to ensure safety and provide information to vulnerable populations, particularly the elderly (Dotto et al. 2010) are needed. Following the 2009 heat wave, the BCCDC collaborated with the Meteorological Service of Canada (MSC) on developing criteria for defining a heat wave and the protocol for calling a heat emergency. In implementing responses, the BCCDC coordinated with large regional agencies such as Fraser Health, Vancouver Health, and MSC on alerts communication, surveillance, and public health messages delivered more broadly via local health agencies and the media, which initiated community intervention plans (BCCDC 2012). Defining the threshold for a heat wave in the region is challenging due to the complex coastal environment, topography, and meteorological responses that create a range of temperature conditions and acclimatization thresholds. Henderson and Kosatsky

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(2012) identified two temperature thresholds that would trigger a heat-health emergency for Metro Vancouver as: ‘‘the average of the current day’s 14:00 observed temperature and the next day’s forecast high is C29 °C on the coast and/or C34 °C inland.’’ This com- plexity warrants further research, particularly into the sea breeze influence, the urban heat island effect, and humidity sources. Additionally, although the BC alert system focuses on daily temperature conditions, research shows that elevated nighttime temperatures and humidity are other important factors in heat-related illness that require additional assess- ment and adaptation measures, especially in the current absence of air-conditioning (Smoyer-Tomic and Rainham 2001). Appropriately targeted advice and intervention measures are the other crucial elements of response during a heat wave. Public communication typically explains the symptoms, who is vulnerable, what actions to take, and what resources are available (Health Canada 2011a, b; Berry et al. 2014b). This information, often delivered in plain language, is usually available online and serves as a resource for the general public; it also forms the basis for outreach through the media. O’Connor and Kosatsky (2008) reviewed online North American heat-health resources and identified key issues such as inconsistencies in information (across and within organizations); focus on potential vulnerabilities without articulation of practical solutions (e.g., risks due to medications); including potentially harmful advice (e.g., advising against using fans due to concerns for dehydration may be confusing to vulnerable people without other cooling methods). Additionally, media reporting on heat waves often place the focus on the wrong subpopulations—children, pets, outside workers, and not the most vulnerable. There is a continuing need to assess awareness and adaptation practices to improve the targeting of messages and outreach activities (Bassil and Cole 2010). Health Canada (2011a, b, 2012) has developed general guidelines on extreme heat events as well as those specifically for informing healthcare practitioners that are applicable across Canada. HealthlinkBC has medically approved heat-illness fact sheets for the public in eight languages available online, with additional access to health practitioners through the provincial health line. Similar information resources are available online for the City of Vancouver (e.g., http://vancouver.ca/people-programs/hot-weather.aspx) and the broader region through Vancouver Coastal Health (e.g., http://www.vch.ca/your-health/). Several Metro municipalities have implemented extreme heat emergency plans; for instance, the City of Vancouver has implemented cooling centers and longer hours for public facilities such as libraries and swimming pools, as well as providing extra outdoor sources of drinking water in the downtown area. The general public has a high awareness of heat events and alerts; but, public health practitioners are not certain that these interventions have led to behavioral changes or adaptations in the most vulnerable groups (e.g., the shut-in elderly, homeless) (Bassil and Cole 2010). There are few systematic reviews of the effectiveness of heat-health adaptations such as alert thresholds, and communication, outreach and inter- vention responses and successes (Bassil and Cole 2010; Bouzid et al. 2013), as more attention has been focused on studying the potential impacts on climate change than on adaptation. Study of the 2009 Metro Vancouver event revealed vulnerable populations and knowledge and intervention measure limitations. That more deaths occurred at home than in institutions may be due to a number of causes such as lack of air-conditioning and passive cooling options in many residences, or to a reduced perception of risk or optimistic belief in the capacity to respond. When the City of Toronto recognized the vulnerability of selected groups of tenants, it initiated a heat awareness campaign for landlords that advised posting heat warnings in prominent areas, checking on known vulnerable tenants, and

123 Nat Hazards providing cooling rooms. Mental health, drug use, and the socioeconomic issues of poverty and marginalization are additional heat-health vulnerabilities deserving further attention. The aging of the Canadian population and the resultant increase in the number of people at risk of heat-related illness is another consideration. Adaptations that cover these com- plexities will require careful attention to the distinctive challenges of these groups. Wolf and McGregor (2013, p 65) indicated that ‘‘Deciphering the drivers of vulnera- bility is key to understanding the social construction of risk, how this might play out on in terms of environmental justice and ultimately explaining the differential societal impact of extreme weather and climate events.’’ Risk mapping associated with extreme heat assessments can offer insights, but few such studies have been undertaken in Canada. In an assessment of vulnerability to heat stress in Montreal, Quebec, Vescovi et al. (2005) found higher heat mortality in neighborhoods with greater population density. Social vulnera- bility (SoVI) metrics and an index were developed for the CCaR and vetted by the practitioner community (Oulahen et al. 2015); future research could build on the neigh- borhood study by Lesnikowski (2010), which could be used in a heat risk study for Metro Vancouver to help inform policy development and planning initiatives. The economic impact of heat waves needs more study in Canada, including Metro Vancouver, where it would be beneficial to study the output effect of a major future event. A practical way of accomplishing this would include questions in the monthly labor force survey regarding loss of work time; in the case of the 2009 event, additional questions could have been inserted following the event. This would parallel what was done for the June 2013 Calgary area flooding catastrophe (Pomeroy et al. 2015), where responses indicated a net loss of 5.1 million hours of work time for that month alone, estimated to correspond to a $485 million output loss (Alberta Government 2013), or about 10% of Calgary’s normal GDP in that period (Davies 2015). When considering adaptations, it is important to assess their potential consequences in case their introduction could create additional, unanticipated risks. For instance, one measure is to make air-conditioned space available, extending opening hours of malls and other public spaces, or even creating temporary cooling spaces; however, cooling towers, a feature of air-conditioned spaces, have been linked to Legionnaires’ disease (Keller et al. 1996; Brown et al. 1999; Nguyen et al. 2006). Therefore, any plans that include increased use of such facilities should be made with awareness of this possible risk. Planners should then ensure that any facilities that may be needed in a heat wave response have adequate servicing and preparation to actually reduce exposure to risk.

6 Concluding remarks

Heat wave events have not historically presented a major challenge for the people of Metro Vancouver. Climate change is expected to increase the occurrence of heat waves affecting the region and will continue to increase into the future. Heat waves in Vancouver are characterized by varying durations (a day to several days) and complex spatial distribu- tions. Contributing factors range from large-scale warming to local-scale alterations in the degree to which sea breezes limit regional temperatures. Although significant trends were not found in many measures of high temperatures in Metro Vancouver, July 2009 broke records at the two available long-term observational sites. The 2009 heat wave and associated high humidity led to major impacts. Although Vancouver International Airport (YVR) only reached 31 °C, some locations experienced

123 Nat Hazards land surface temperatures approaching 40 °C. Excess mortality is based on this latter value. Impacts included those linked with or related to health, social, and economic issues. In part, these consequences arose due to two interconnected issues: the rare occurrence of these events and the inadequate society-wide preparation. Given the fact that such events are projected to increase in frequency, steps toward improving preparedness and sugges- tions designed to help reduce future impacts, should include working to increase public awareness of the occurrence of such events and their associated risks, including demon- stration of the fact that the impacts may duplicate or be similar to the more common experiences of cities and regions elsewhere in Canada. In summary, extreme heat conditions associated with Metro Vancouver’s unique physical, social, and economic conditions led to significant negative impacts/outcomes in July 2009. Much can be learned from other regions of Canada, of North America, and around the world in terms of actions designed to reduce the impacts of, and avoid, such consequences in the future. Actions taken in response that model effective adaptation will have relevance to cities in other countries that have similar climates to that of Metro Vancouver, and may therefore be equally unprepared.

Acknowledgements This research was conducted within the Coastal Cities at Risk (CCaR) Network, which is sponsored by the International Development Research Centre (IDRC) Grant No. 106372-010 together with the Canadian Institutes of Health Research (CIHR), the Natural Sciences and Engineering Research Council of Canada (NSERC), and the Social Sciences and Humanities Research Council of Canada (SSHRC). We would like to thank Andrew Berrisford of BC Hydro who kindly provided electricity usage information, Ruping Mo from Environment Canada who provided climatological information, and Sarah Henderson, from the BC Centre for Disease Control, who provided information on the 2009 heat wave impacts and responses in BC. We would particularly thank our international partners in the CCaR research network for discussions regarding to adaptation to extreme events in coastal cities.

Compliance with ethical standards

Conflict of interest The authors declare that they have no conflict of interest.

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