Climate change — who is most vulnerable and why?
Daniel Jubas-Malz, a recent graduate of the Master of Public Health program at the Dalla Lana School of Public Health, and Melissa Perri, a Master of Public Health candidate at the Dalla Lana School of Public Health, both have an ongoing interest in climate change and vulnerability. Together, they contributed to Climate change and health equity: Newcomers, women, and youth, a collaboration between the Greenbelt Foundation and the Alliance for Healthier Communities. 
In this NCCDH student guest blog post, Daniel Jubas-Malz and Melissa Perri discuss climate change vulnerability, reflecting on some of the limitations of the climate change literature.
Key definitions related to climate change vulnerability
Climate change is associated with frequent and intense weather events, variable temperature patterns and flooding, all of which can have direct and indirect impact on individual and community health.  The World Health Organization has has reported that between 2030 and 2050, climate change will account for an additional 250,000 deaths and cost health systems billions of dollars annually. [2,3]
Exposure is just what it sounds like: a person or a group is exposed to a climate-related stressor,  for example, a very hot day, or a severe thunderstorm.
Sensitivity has to do with what makes a person or a group likely to be susceptible to the stressor.  For example, elderly populations and/or those with pre-existing conditions may have weakened physiological systems that reduce heat sensitivity and sweating, thereby increasing the impact of exposures to high temperatures.
Adaptive capacity is an individual or group’s ability and/or capacity to respond appropriately to stressors and/or impacts and minimize negative health consequences.  For instance, farmers risk losing crop in annual yields from variable climate patterns. Their ability to change practices (e.g., diversifying crops) demonstrates their capacity to adapt to changing climate.
Intersectionality is a concept that has gained traction in contemporary feminist theory, as well as in anti-racism and public health.  Davis states that intersectionality “refers to the interaction between gender, race, and other categories of difference in individual lives, social practices, institutional arrangements, and cultural ideologies and the outcomes of these interactions in terms of power.” [7(p68)]
Who is vulnerable to the health impacts of climate change, and why?
Although climate change events impact the general population, the health impact of climate change is more severe for marginalized groups worldwide.  Structural factors like income distribution, poverty, inadequate living conditions, racism and gender discrimination drive climate-related health inequities among specific populations. [12,13] Visiting or remaining in air conditioned environments, for example, are common adaptive strategies used to minimize health illnesses related to increases in temperatures. 
However, populations residing in low-income areas or those who cannot afford an air conditioner are less able to rely on this adaptive strategy - thereby increasing their vulnerability to heat related illnesses. Moreover, if the air conditioner is powered by fossil fuels, this short-term adaptive strategy is actually contributing to future warming through increased greenhouse gas emissions.
Throughout our graduate studies and in contributing to Climate change and health equity: Newcomers, women, and youth, we familiarized ourselves with the climate change-related literature and learned that a group’s climate change vulnerability depends on a mix of factors that either increase risk, or serve to protect from climate change impacts.
In the literature, the following groups are often considered the most vulnerable:
- elderly citizens
- those considered low socio-economic status (SES)
- those with pre-existing health conditions
- those living in Northern regions
- Indigenous populations
- those living by the coast
- working populations
- isolated/rural populations
- urban populations
- individuals who live off the land
- racialized populations
- those vulnerable due to gender and sex differences
- newcomer populations
- materially deprived populations
It is not within the scope of our blog to explore what drives vulnerability within every possible group impacted by climate change. Instead, we have explored what the literature tells us about vulnerability in the context of being Indigenous, in the context of gender and sex and in the context of having a pre-existing health condition. Noting the limitations of considering vulnerability in the context of one single factor, we have then considered the vulnerability of someone who identifies with aspects of each of these three contexts.
A snapshot of what the literature tell us about Indigenous populations in relation to climate change:
According to Donatuto and colleagues, climate change represents “one of the potentially most devastating threats to the health and well-being of Indigenous populations.” [15(p365)] Indigenous populations already experience structural inequities related to race, income, education, and employment.  Environmental changes affect land-based activities essential for some Indigenous Peoples’ livelihoods (e.g., travelling options ) and factors that help protect against climate impacts (e.g., cultural connectedness).  In addition, changing seasonal patterns alter migration habits and distribution of the species that some Indigenous communities hunt for food. [19,20]
A snapshot of what the literature tells us about gender and sex in relation to climate change:
Gender and sex influence climate impacts, in part because of gender roles and expectations within western contexts. [21,22] Income has been reported to contribute to vulnerability in women, while men are reported to be more vulnerable due to their occupations. 
Gendered-norms —accompanied by factors such as gender-driven employment discrimination —often impact income stability for women.24,21 In addition, lower income and income stability may limit access to sufficient housing, quality food and air conditioning for women. [24,21]
Men are overrepresented in manual labour, for example in jobs such as construction work, mining and firefighting. [25,26] This may increase male vulnerability because it directly increases their exposure to climate-related impacts (e.g., extreme temperatures).
A snapshot of what the literature tells us about individuals with pre-existing health conditions in relation to climate change:
People with pre-existing conditions have weakened physiological systems that make them more sensitive to environmental changes. Health consequences are expected to vary depending on specific health complications. For example, a person who already has asthma or another respiratory health issue may be more sensitive to extreme temperatures and see their symptoms worsen. Climate change events can exacerbate existing conditions or create new illnesses. [27,28]
Considering the case of someone who identifies with each of the three contexts above
Now, things become more complex when we attempt to look at all of these factors together. Consider the possible climate vulnerability of an Indigenous man with a pre-existing condition.
We know that men are more likely to experience occupational exposures. And, that some Indigenous men may be household hunters, which also increases exposure to harsh temperatures and other environmental factors. If this person also had a pre-existing condition, such as a respiratory disease, they would not only be more exposed to extreme temperatures, but they would also have an increased risk of exacerbating current health issues or creating new ones. As climate change disrupts patterns of herd migration and travel options, this person may also face greater difficulty accessing traditional food sources and engaging with other Indigenous practices.
We realize that the short analysis above is a far from perfect exploration because there are many other factors affecting strength, resilience and vulnerability that we are not accounting for. The incompleteness of this example points to the challenges with the climate change literature discussed below.
Limitations of the climate change vulnerability literature
As we considered the climate-related literature, we noticed two interesting trends:
First, groups are often framed solely as victims that have been affected by climate change, rather than a needed voice and driving partner in adaptation efforts. 
Second, we noticed that populations or groups are often studied for one — or a few — specific vulnerability factors. As others have noticed, [6,30] the research often does not consider the multiple factors that intersect in complex systems. For example, in our examples above, we cite several articles on Indigenous populations, those who are vulnerable due to sex and gender, and those who have a pre-existing health condition.
However, less research is readily available for the case of an Indigenous man who is experiencing multiple other factors that influence both strength and vulnerability. In their discussion of climate scholarship in relation to Indigenous health, Parkes, de Leeuw and Greenwood  identify opportunities to improve the way climate research is conducted by, among other things, applying a more intersectional approach to research methods and data analysis.
If researchers and practitioners were to consider multiple intersecting factors, and account for community assets, their work would likely be far more useful to public health practitioners and policy-makers tasked with creating climate change adaptation plans.
Climate change is a complicated issue, one that requires dedication from multiple systems, including health. Public health researchers, practitioners and policy-makers have a unique opportunity to explore intersecting factors that influence both strength and vulnerability. Public health is also well positioned to engage with communities and tailor programs, practices and policies to adapt to climate change. Although daunting, we have the resources, the passion, the assets within communities and the belief that our efforts will make a difference. Yes, the climate is changing — but so can we.
Special thanks to Dr. Chris Buse and Pemma Muzumdar for their guidance and support with earlier drafts.
Photo credit: Jeremy Goldberg
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