Heat-Health Communication in Canada: Identifying Opportunities to Refine Existing Messaging and Dissemination Strategies to Protect Canadians from Extreme Heat

Abstract

Introduction: Extreme heat events (EHEs) are a growing threat to public health. Given that EHEs will continue to increase in frequency and severity as the global climate changes, heat alerts and public health messages are of growing importance to public health protection. In Canada, extreme heat alert and response involves federal, provincial, territorial, and regional agencies. This includes issuing extreme heat warnings and associated heat-health messages when specific regional heat warning criteria are met and publicizing these messages and general heat-health information via various media (e.g., newspapers) and online channels (e.g., health agency websites). However, no established standards exist to support journalists or public health agencies with recommended content to include in their EHE heat-health protection materials. As a result, little is known about heat protection and mitigation information communicated to the public via these avenues.

Purpose: This dissertation aimed to characterize and assess Canada's current heat-health messages and communication practices to protect the public from hot weather and EHEs.

Methods: Using a qualitative content analysis method, we examined how the communication network currently operates to distribute heat-related emergency preparedness warnings in Canada and what health protective information is promoted to the public during an EHE using online media coverage published on the deadliest EHE in Canadian history – the 2021 Heat Dome (Study 1). We then analyzed visual content to determine how images support or counter the written messaging (Study 2). We then assessed the heat-health messaging published on regional, provincial, and national public health agency websites in Canada to determine which agencies are currently disseminating information (Study 3). The public health agency produced heat-health content and analyzed it for language accessibility, readability, suitability, and comprehensibility (Study 4). We then evaluated the knowledge, risk perceptions, perceived vulnerability, and practices of a sample of older adults in Canada using an online questionnaire related to heat stress prevention and management and their access to heat-health communication and information (Study 5).

Results: We found that during an EHE, the media primarily focuses on record-breaking temperatures and infrastructure impacts instead of guiding reliable strategies for reducing the health impacts of heat. When available, heat-health messaging often includes contradictory content, inconsistent language, and overly simplified messaging and typically does not address heat-vulnerable groups or those residing outside urban centers (Study 1). We also found that most images used in the news coverage were incompatible with, and frequently contradicted, evidence-based heat protective actions (Study 2). We also found that although a wide array of heat-health materials was identified on public health agency websites, availability across agencies and provinces was variable. In many instances, the material differed considerably in the scope of content (Study 3). Further, we found that the material is available in a few languages and typically exceeds the recommended reading level due to the use of complex language (Study 4). Lastly, we found that risk perception and knowledge of heat stress are low among older adults, indicating that current warnings are ineffective at inspiring behavioural adaptation (Study 5).

Conclusion: Despite an observed effort to disseminate heat-health protective messaging across Canada, this thesis provides evidence that a comprehensive and standardized messaging strategy is needed to ensure the public is aware and knowledgeable of the threat posed by extreme heat.