In 2015, the United Nations launched the Sustainable Development Goals (SDGs) with the bold and optimistic intent to eradicate poverty, protect the planet and promote global peace and prosperity by 2030. The COVID-19 pandemic, however, has impacted the timeline and has illuminated the interconnection of human and natural systems. Likewise, it has increased our awareness that we cannot have health and well-being when massive disparities and disruptions of Earth’s natural systems persist.
To appreciate what is meant by planetary health, we start with a brief review of the historical events that shaped what would become disciplines, initiatives, partnerships, policies and efforts broadly characterized as ‘public health,’ ‘global health’ and ‘One Health.’
Public, Global, Planetary and One Health Defined
Public health as a discipline took shape as we increased our knowledge and understanding of infectious agents, the environmental factors that contributed to human disease, infection, illness or death, and the sociopolitical factors that influenced threats to health. When physician John Snow, the ‘father’ of epidemiology (the incidence, distribution and control of disease), strongly advocated for the link between something unseen in the water supply and the cholera deaths taking place around the Broad Street Pump in London in 1854, he challenged long-standing beliefs about causes of illness and death (Snow, 1855). When his actions led to the outbreak ending, he ushered in a new era of understanding and discovery with a focus on public health and prevention (Tulchinsky, 2018).
Formal colleges and schools of public health emerge some 50 years later in the early 1900s. Charles-Edward Amory Winslow, Yale’s first Chair of the Department of Public Health, defined the field of public health and his definition continues to stand the test of time:
Public health is the science and the art of preventing disease, prolonging life, and promoting physical health and efficiency through organized community efforts for the sanitation of the environment, the control of community infections, the education of the individual in principles of personal hygiene, the organization of medical and nursing service for the early diagnosis and preventive treatment of disease, and the development of the social machinery which will ensure to every individual in the community a standard of living adequate for the maintenance of health.
(Winslow, 1920, p. 30)
In contrast, global health focuses on the health of the population in each country. Koplan et al. (2009) from the Consortium of Universities for Global Health (CUGH) defines global health as ‘an area for study, research, and practice that places a priority on improving health and achieving health equity for all people worldwide’ (p. 1995). Velji and Bryant (2011) offer a definition of global health that will resonate with many:
The concept of global health reaches beyond the rich-poor dichotomy and geographic boundaries and borders to the forces that separate the powerful, free, privileged populations from the population that is powerless and unfree. In its acceptance of human diversity, global health is an expression of support for the human rights enshrined in the WHO constitution, charters, and declarations and in the instruments of governance of several other nation-states.
(Velji & Bryant, 2011, p. 307)
A decade later, Salm et al. (2021) conducted a review of articles that had been published between 2009 and 2018 and included one or both terms ‘global health’ and ‘public health.’ They identified 33 definitions of global health, characterized by attention to worldwide improvements to health, operationalized principles of justice and ethical frameworks, and influence on political decision-making and resource allocations. Salm and colleagues’ review demonstrates the ongoing emergent nature of ‘global health’ as a construct representing broad and diverse efforts and perspectives focused on advancing the health of populations around the globe. Additionally, global health carries a commitment to addressing a broader array of health threats and inclusion of numerous disciplines engaged in solving those threats.
In 2007, the American professional associations of medicine and of veterinary medicine came together to summarize the concept of One Health. Asokan (2015) reports that this combined task force defined One Health as ‘a system approach which includes disciplines of human medicine, veterinary medicine, and other related scientific health disciplines working locally, nationally, and globally to attain optimal health for people, animals, and our environment’ (Asokan, 2015, p. 3). Those involved in advancing the health of humans, animals and the environment while addressing the aspects of each, and the interplay among these, often characterize their work and teams as ‘One Health.’ Zoonoses, infections spread from animals to humans, are often the focus of One Health’s related research and education. Some countries in Africa and Asia (e.g., Cameroon, Rwanda) have adopted One Health’s national platforms, encouraging respective ministries of health, wildlife and livestock to work together to address infectious zoonotic threats to health and to mitigate outbreak risks.
History demonstrates consistent growth in understanding, appreciating and addressing the complex and multifaceted interplay of risks, protections, threats and resources surrounding human, animal and environmental health. Borders quickly become irrelevant when facing situations such as zoonotic threats, environmental emergencies or regional instabilities. Global, multidisciplinary and multisectoral cooperation, whether formal or organic, has much potential to mitigate risks and to prevent severe consequences to the health of individuals, communities, nation-states and the globe.
