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Planetary Health: The new frontier for 21st century public health

An ecologically sustainable way of life may be the only truly "healthy" life available to us, in the long run.

While I started out as a family physician, I moved into public health 40 years ago because I was more interested in preventing disease and injury than treating it. But since most of the determinants of the health of the population lie beyond the health sector, that means working ‘upstream’, beyond health care, on the broader social, economic and environmental factors that influence health.

Canada has been a leader in understanding the determinants of health, but both here and globally, the focus has been primarily on the social and economic determinants of health. These include our living and working conditions and, especially, the way that these factors are inequitably distributed, resulting in inequalities in health.

"We have become a force equal to – or sometimes greater than – nature."

However, in our focus on the social determinants we have largely ignored another large set of upstream factors; the natural ecosystems that are the ultimate determinants of our health. These ecological determinants of health include air, water and food as well as the fuels and materials upon which our societies depend,

Natural systems also detoxify many of our wastes, protect us from UV radiation from the sun, and have given us the relatively benign climate for the last 11,000 years – the Holocene – within which agriculture and civilization have emerged. But increasingly, earth scientists believe the Holocene is coming to an end, and we are entering the Anthropocene, a new geological epoch that humans are creating.

We have become a force equal to – or sometimes greater than – nature. We are changing the climate and acidifying the ocean; have made a hole in the ozone layer; are depleting fisheries, forests and soils; have changed fundamental natural cycles of nitrogen and phosphorus, and are creating a sixth ‘Great Extinction’.

In a 2015 report for the Canadian Public Health Association, my colleagues and I described the profound implications for the health of the population of these global ecological changes. At the same time as we were working on this The Lancet, one of the world’s leading medical journals, established a Commission on Planetary Health, a term coined by the editor, Dr. Richard Horton, and defined as “the health of human civilization and the state of the natural systems on which it depends”.

"We need to adopt a new ‘eco-social’ approach within the field of population and public health."

So in the 21st century public health has to expand its focus to include the state of the Earth’s ecosystems that are the ultimate determinant of our health. This in turn means addressing the social, economic and technological forces that are driving changes in these systems.

Because the key point about the global ecological changes that constitute the Anthropocene is that we are causing them, and we alone can prevent them. Addressing these new threats to health will require significant changes not only in our social and economic systems, but in our culture and its underlying values. 


We need to adopt a new ‘eco-social’ approach within the field of population and public health. You can expect increasingly to hear public health professionals in Canada and around the world calling for public policies and corporate actions that lead to sustainable human development, and condemning those that do not.

We will be speaking out against fossil fuels and in favour of conservation and renewable energy; against urban sprawl and in favour of healthy, sustainable, livable communities; against unsustainable agricultural and resource extraction practices and in favour of low-meat diets and resource conservation and recycling.

We will increasingly need to speak out against an industrialized economic system that blindly pursues GDP growth to the exclusion of any serious consideration of its impacts on the Earth’s systems and the health of the population, especially those who are most vulnerable.

Above all, we will stress that in a finite world, social justice requires that we who live in high-income countries will have to take less of the Earth’s resources and ecosystem services so that others may have their fair share. We will focus instead on the significant health benefits of a more ecologically sustainable way of life and the need to prioritze human development over economic development. 

These and similar issues are the new frontiers for public health action in the 21st century. You will be hearing from us, I hope you will be working with us.

Hear more from Dr. Hancock in the latest episode of Upstream Radio!




TH_-_PHSP.jpgDr. Hancock is a Professor and Senior Scholar at the School of Public Health and Social Policy, University of Victoria. He was lead author and editor of the report for CPHA on the ecological determinants of health, and an expert reviewer for the report of the Lancet Commission on Planetary Health.

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