Spatiotemporal analysis of regional socio-economic vulnerability change associated with heat risks in Canada

Abstract

Excess mortality can be caused by extreme hot weather events, which are increasing in severity and frequency in Canada due to climate change. Individual and social vulnerability factors influence the mortality risk associated with a given heat exposure. We constructed heat vulnerability indices using census data from 2006 and 2011 in Canada, developed a novel design to compare spatiotemporal changes of heat vulnerability, and identified locations that may be increasingly vulnerable to heat. The results suggest that 1) urban areas in Canada are particularly vulnerable to heat, 2) suburban areas and satellite cities around major metropolitan areas show the greatest increases in vulnerability, and 3) heat vulnerability changes are driven primarily by changes in the density of older ages and infants. Our approach is applicable to heat vulnerability analyses in other countries.

Keywords: climate change; demographic change; heat vulnerability; regional planning; spatiotemporal modelling; urbanization.

Figure 1:

Population density (persons per km²) in 2011 for all Canadian provinces (British Columbia, Alberta, Manitoba, Saskatchewan, Ontario, Quebec, Newfoundland and Labrador, New Brunswick, Nova Scotia, and Prince Edward Island). Data from the 2011 Canadian census, at subdivision level.

Figure 2:

Percentage Change of Heat Vulnerability in Canada from 2006 to 2011.

Figure 3:

Clustering of the percentage change in heat vulnerability in Canada. Red indicates high increase in vulnerability in both the dissemination area and the surrounding dissemination areas. Blue indicates low increase or decrease in vulnerability in both the dissemination area and the surrounding dissemination areas. Pink indicates an isolated dissemination area with low or negative vulnerability increase, surrounded by dissemination areas with high vulnerability increases. Orange indicates an isolated dissemination area with high vulnerability increase, surrounded by dissemination areas with low vulnerability increases or vulnerability decreases. Gray indicated dissemination areas without spatial clusters.

Figure 4:

Comparison between the percentage of dissemination areas with heat vulnerability change of >25% and the percentages of dissemination areas with high-high clusters from LISA map in 7 cities (Toronto, Montreal, Vancouver, Ottawa, Edmonton, Calgary, and Victoria) in the Lower Canada.

Figure 5:

Comparison of seven cities in Canada based on the temporal change of social vulnerability associated with heat risks from 2006 to 2001. Red indicates the highest increase (>25%) in vulnerability, while green indicates a decrease or a low increase (<5%) in vulnerability.

Figure 6:

Comparison of seven cities in Canada based on the spatiotemporal change of social vulnerability associated with heat risks from 2006 to 2011. Red indicates significant clusters of dissemination areas with high increase in vulnerability; grey indicates dissemination areas with either low increase in vulnerability or lack of clustering.