WHAT IS PLANETARY HEALTH?
Planetary health represents the highest possible level of worldwide health, well-being and equity by means of sensible human systems management (political, economic, and social) without compromising the future of humanity or the planet’s natural systems. More simply: planetary health is the health of human civilisation and the natural systems on which it depends. The latter must always remain within safe environmental limits (Whitmee et al., 2015; Brousselle and McDavid, 2020).
Human activity has affected Earth’s natural systems, especially its biosphere, hydrosphere, edaphosphere, atmosphere and geosphere, altering their dynamics and composition. This fact represents an obvious problem because people’s health and well-being depend on these spheres.
WHERE COULD A TURNING POINT IN THESE IMPACTS BE DETECTED?
The key is the industrial revolution. Since then, society has mobilised to exploit resources and positively consider economic growth synonymous with well-being. This paradigm has led to population growth, increased life expectancy, reduced infant mortality and reduced extreme poverty. Yet, it has also affected our natural environment (Brousselle and McDavid, 2020).
Beyond the struggle for the preservation of the environment and the sustainable exploitation of natural resources, there is now a growing awareness that having a sick planet -i.e. one pushed to its limits without any real strategy for a cure- increasingly lowers people’s quality of life to the point of death. Health promotion has focused on the social determinants of health, including equity, but paid little attention to ecological ones.
The situation is problematic because the most fundamental determinants of human health are the natural systems that make the earth habitable and provide us with air, water, food, fuel and materials for life. Yet, the economic and social development we have created to meet the social determinants of health threaten natural systems. In addition, there is an uneven distribution of the benefits and burdens of such development, resulting in both ecological and social injustice (Hancock, 2021).
The World Health Organisation joins in these declarations and reaffirms that the source of human health is nature. Therefore, and without any doubt, the most crucial task facing health promotion in the 21st century is to turn its attention to planetary health.
CLIMATE CHANGE AND HUMAN HEALTH
Although it is difficult to attribute observed health changes in a population to recent climate change, a consistent pattern of weather- and climate-related changes is now becoming evident in many regions of the world. Risks affect unevenly, especially in poorer and more vulnerable regions, amplified by pre-existing high rates of climate-sensitive diseases and conditions. The health consequences of a 3-5 ⁰C world warming by 2100 will be severe, both directly and through massive social and economic disruption (McMichael, 2014).
Today, escalating human numbers, an expanding global middle class of consumers, intensified economic activity, and pervasive technologies are placing excessive pressure on the natural biophysical and ecological systems that form Earth’s life support system. All in all, this leads to planetary overstress, where the well-being, health and survival of human populations and other species are at risk (McMichael, 2014).
Listed below are some examples of elements and situations that the human species will most likely suffer as a result of the new planetary conditions:
- exposure to excessive heat and radiation
- the physical hazards of extreme weather events
- mass migrations and armed conflicts
- disturbances in pollination
- alterations in the functioning of ecosystems (decoupling of species life cycles and changes in trophic relationships)
- changes in crop harvesting and yield
- the health of livestock on which we depend
- increased transmission of infectious diseases
- disruption of social relations and the economy
- loss of or changes in jobs
- conflicts caused by climate-related resource scarcity (water, food, habitable land)
PLANETARY HEALTH AND FOOD
In order to maintain planetary health, human activities must limit the use of the Earth’s resources within finite limits and avoid environmental degradation. Concerning food, we know that agriculture occupies almost 40% of the world’s land. Food production causes up to 30% of global greenhouse gas emissions and 70% of freshwater use (EAT-Lancet, 2019).
Food systems thus represent a significant use of natural resources and contribute significantly to climate change. At the same time, they threaten human health through food insecurity. Moreover, current food patterns, rich in animal products and excessive in calories, are detrimental to both the population and the planet’s health (Fresan & Sabate, 2019).
Sustainable food systems are an important component of a planetary health strategy (Canavan et al., 2017) to:
- Promoting nutrition.
- Minimising the environmental footprint: the growing demand for food and the increase in meat production and consumption in recent decades in a context of declining availability of arable land and water.
- Reducing the threat of infectious diseases: the intensification of livestock production -a consequence of the previous point- has serious impacts. Land clearing, for example, is counterproductive for agriculture because it disrupts ecosystems. It also increases human-wildlife interactions and leads to the proliferation of diseases (increased risk of zoonoses).
Along these lines, the EAT-Lancet Commission introduces a global planetary health diet:
As can be seen, a plant-based diet stands out. Whole grains, fruits, vegetables, nuts and pulses are a large part of the diet. Meat and dairy are important but in significantly smaller proportions.
A daily practice of planetary health can help us thrive by connecting with nature and the world and becoming stewards of our environment (Rogers, 2021).