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Planetary Health: Focusing on the Intersection of Human Health and the Earth System

Authors and Affiliations

  • Carlos A. Faerron Guzmán, Planetary Health Alliance, Johns Hopkins University, Baltimore, Maryland, USA (email: carlos.faerron@jhu.edu)

  • Nicole Redvers, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada

  • John S. Ji, Vanke School of Public Health, Tsinghua University, Beijing, China

  • Oliver Lacey-Hall, Sunway Centre for Planetary Health, Sunway University, Kuala Lumpur, Malaysia

  • Jemilah Mahmood, Potsdam Institute for Climate Impact Research, Member of the Leibniz Association, Potsdam, Germany

  • Oskar Masztalerz, Johns Hopkins Bloomberg School of Public Health and Johns Hopkins Institute for Planetary Health, Baltimore, Maryland, USA

  • Alexandra L. Phelan, Johns Hopkins Center for Health Security, Baltimore, Maryland, USA

  • Johan Rockström, Institute of Environmental Science and Geography, University of Potsdam, Potsdam, Germany

  • Samuel S. Myers, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA

Abstract

The core insight of Planetary Health is that the Earth crisis is fueling a global health crisis. This field examines the connections between human health and Earth’s natural systems. The review discusses drivers of environmental degradation and their relation to global environmental change, particularly focusing on six Planetary Boundaries that pose increased health risks, particularly for vulnerable populations. Earth system justice is emphasized, advocating just solutions for intergenerational and intragenerational inequities. Sustainable food and energy systems, circular economies, governance reforms, and cross-sector collaboration are highlighted as necessary actions. The importance of Indigenous knowledges is also emphasized for building resilience and aligning human well-being with natural systems' health.

Keywords

  • Planetary Health

  • Earth system

  • Planetary boundaries

  • Sustainable development

  • Climate change

  • Global health equity

1. INTRODUCTION

1.1 Emergence of Planetary Health

Over the past 70 years, human health and well-being have improved significantly alongside increases in life expectancy, which rose from 46 years in 1950 to 71 in 2021 largely due to poverty reduction and public health innovations. Despite these advances, stark disparities remain; life expectancy varies from 54 years in Nigeria to 86 years in Monaco. Factors hindering the achievement of Sustainable Development Goals (SDGs) are exacerbated by challenges such as the COVID-19 pandemic, which increased poverty and food insecurity, pushing millions into extreme poverty and worsening existing inequities. The exploitation of natural resources has led to severe environmental degradation, and six of the nine Planetary Boundaries have already been transgressed, which threatens both past and future health advancements. Future challenges hinge upon three fronts: safeguarding Earth's stability, preventing harm to current and future generations, and ensuring equitable access to resources for a healthy life.

2. EXAMINING THE DRIVERS OF LARGE-SCALE ENVIRONMENTAL CHANGES

This section investigates key socioeconomic drivers of environmental deterioration, including:

2.1 Demographic Transitions

  • Global population surpassed 8 billion, leading to increased demand for food, water, and energy. This poses significant stresses on natural systems, exacerbating deforestation, biodiversity loss, and resource scarcity.

  • Urbanization trends can help ease resource consumption on a per capita basis but may also compound pressures on infrastructure and ecological systems.

  • The consumption patterns of high-income nations are disproportionately higher, accounting for a significant percentage of global resource usage, despite lower population growth.

2.2 Technological Advances in Resource Extraction

  • Innovations in resource extraction have increased efficiency but have also led to habitat destruction and pollution. Technologies like automated mining can reach depths of 1,000–3,000 meters but still face shortcomings in sustainability.

  • This can lead to a "rebound effect", where improved efficiencies contribute to increased total resource extraction due to lower relative costs.

2.3 Industrialization

  • Industrial operations, particularly those relying on fossil fuels, are major sources of pollution and greenhouse gas emissions. Inadequate controls in lower-income countries exacerbate these issues.

2.4 Societal Values and Economic Priorities

  • Economic growth and consumerism prioritize exploitation of resources over equitable and sustainable practices. Economic systems often fail to account for environmental destruction and its impacts on health.

2.5 Governance Failures

  • Policy failures, including poor accountability and participation from marginalized communities, reinforce environmental inequalities by favoring short-term economic gains over sustainable practices.

2.6 Rapid Urbanization

  • Urban areas, which house over half of the global population, significantly contribute to energy consumption and emissions. Poorly planned urban development leads to increased health hazards.

2.7 Agricultural Practices and Expansion

  • Intensive agriculture contributes to biodiversity loss, deforestation, and soil degradation. Structures for sustainable farming and resource management are necessary to prevent further decline of arable land.

3. ANTHROPOGENIC EARTH SYSTEM CHANGES

Human actions are altering Earth’s natural systems at an accelerating rate, described through the concept of Planetary Boundaries, which identify thresholds for crucial environmental processes:

3.1 Interactions Among Changes and Tipping Elements

Changes within Earth’s systems do not occur in isolation; they can compound and create feedback loops leading to catastrophic outcomes, such as tipping points that, once crossed, lead to irreversible changes in climate or ecosystems.

4. DIRECT AND INDIRECT IMPACTS ON HUMAN HEALTH AND WELL-BEING

The review identifies critical health impacts due to environmental change, detailing diverse dimensions of health affected including:

4.1 Nutrition

  • Global environmental change presents risks to food security, affecting crops and nutritional quality. Changes in climate could decrease yields and increase nutrient deficiencies, principally for vulnerable populations.

4.2 Infectious Diseases

  • Climate-induced changes influence the spread of infectious diseases, particularly vector-borne illnesses. The geographical ranges of pathogens expand, leading to potential outbreaks in new regions.

4.3 Noncommunicable Diseases (NCDs)

  • Pollution contributes significantly to the rise in NCDs. Factors include pollutants from industry and transport that increase health risks.

4.4 Direct Injury and Displacement

  • Natural disasters linked to climate change become increasingly frequent, leading to injuries, deaths, and the displacement of populations.

4.5 Sexual and Reproductive Health

  • Exacerbated environmental stresses contribute to adverse outcomes in reproductive health, including increased maternal and infant mortality rates.

4.6 Mental Health

  • Mental health declines are linked to environmental degradation, with increased rates of anxiety and depression following climate events.

5. INEQUITY IN ENVIRONMENTAL HEALTH IMPACTS

The review emphasizes disparities in health impacts, which disproportionately affect low-income and marginalized groups. Factors include access to resources, adaptive capacities, and social equity.

5.1 Transforming Back to a Safe and Just Corridor

  • Ensuring environmental equity and just transitions is vital. The framework for Earth system justice (ESJ) encompasses justice for all generations, species, and communities.

6. SOLUTIONS FOR RAPID TRANSFORMATIONAL CHANGE

The need for systemic changes to sustain natural ecosystems while promoting equitable health is stressed with several proposed solutions:

6.1 Reimagining Energy Systems

  • Transitioning from fossil fuels to renewable energies is critical. Advances in storage technology promote resilience in energy systems with significant reductions in emissions as a goal.

6.2 Transforming Food Systems

  • Sustainable agricultural practices and dietary shifts are highlighted for their potential benefits. Approaches like regenerative agriculture can enhance soil health, reduce pollution and greenhouse gas emissions, while also improving food security.

6.3 Reinventing Transportation Systems and Built Environments

  • Sustainable urban design and transportation alternatives can significantly improve public health and reduce emissions.

6.4 Transforming Economic Systems

  • Transitioning from growth-based economies to those that prioritize sustainability and well-being is required, including adopting circular economy practices.

6.5 Social, Behavioral, Narrative, and Value Change

  • A cultural shift is essential to appreciate the intrinsic value of nature, emphasizing sustainability and stewardship.

6.6 Governance Reform

  • Strengthening governance frameworks by promoting accountability and inclusiveness is necessary for equitable environmental policies.

6.7 Strengthening Community Resilience and Local Collaboration

  • Empowering local communities through resource-efficient infrastructure and engagement strategies helps build long-term resilience to environmental change.

6.8 Achieving Earth System Justice and Social Equity

  • Policies must prevent future injustices, driving equitable distributions of resources and addressing disparities linked to environmental health risks.

7. CONCLUSION

The current mode of living and consuming is unsustainable, leading to conditions that threaten future health and biodiversity. A Great Transition is required, anchored in Earth system justice principles that promote accountability and intergenerational equity, ensuring a thriving future for humanity and all life forms. Transformative strategies that incorporate health into environmental planning across sectors and governance are pivotal in addressing the intertwined crises of health and environment.