The World Health Organization recently reported that 99% of humans breathe dangerous levels of air pollution.

That means that the breath you’re taking right now could be harming your body, damaging cells, accumulating in your organs, shaving time off your life.

Every year, more than 8.7 million people die prematurely because of air pollution. The vast majority of these deaths are preventable, owing to the global reliance on fossil fuels and industrial processes that contaminate the air, water, and soil. 

The fact that people keep dying from polluted air shows the profound disconnect at the heart of modern human society, where air pollution continues to be allowed because the processes that cause it generate a financial profit. This overriding value has led to the climate and biodiversity we find ourselves stuck in, but it’s also resulted in the emergence of an interdisciplinary field that seeks to stop and even reverse the unfolding catastrophe: planetary health.

Practitioners and advocates of planetary health are seeking to radically transform the status quo by elevating Indigenous perspectives on the environment that emphasize the interconnectedness of all life. Under this framework, it’s understood that harm leads to more harm in a vicious cycle, but also that the reverse is true — flourishing is expansive as well.

Planetary health is a big picture, all-encompassing field that invites all areas of studies that intersect with the climate and biodiversity crisis, from people involved in food security and water access, to those working on urgent matters of racial justice.

The field has gained prominence in recent years as the health impacts of environmental decline become increasingly devastating.

This year’s World Health Day is dedicated to promoting planetary health and calling for immediate climate action to usher in an era of environmental conservation and restoration.

“Are we able to reimagine a world where clean air, water, and food are available to all?” the World Health Organization asks people as part of its World Health Day efforts. “Where economies are focused on health and well-being? Where cities are liveable and people have control over their health and the health of the planet?”

3 Things to Know About Planetary Health 

• Already, more than 13 million deaths annually can be attributed to climate impacts. 
• Environmental pollution is a leading killer of people worldwide. 
• Climate action and environmental conservation are ultimately public health interventions. 

Planetary Sickness 

Just as the various systems of the human body combine for a holistic whole, so, too, do the various systems of planet Earth. 

As you might remember from early science lessons, these systems are the geosphere, biosphere, cryosphere, hydrosphere, and atmosphere. Each and every one of them has been severely impacted by human activities in ways that jeopardize human health.  

The geosphere has been so heavily altered by human waste and pollution that a new era in the rock record has emerged, which archaeologists have labeled the Anthropocene (the prefix "anthropo" referring to human activity). Various industrial activities, from fracking to construction to industrial agriculture to plastic production, have heavily degraded and polluted more than 75% of the planet’s surface. 

As these trends worsen, groundwater supplies are being polluted and soil fertility is diminishing, making it harder to grow food. Further, as land turns to desert, human habitats are eroding, and communities are becoming more exposed to extreme storms and natural disasters like landslides and forest fires. 

The biodiversity that makes up the biosphere has suffered extreme losses as well. In the last 50 years, wild species have declined by 68% worldwide. More than 1 million plant and animal species face extinction in the years ahead.

Biodiversity enables our global food system, with insects pollinating a majority of the world’s crops, and plants forming the basis of our diets. As human activities disrupt more and more wildlife, infectious diseases like COVID-19 are becoming more common. 

Few systems have been as affected as the cryosphere, which refers to the planet’s vast and rapidly melting stores of ice. Between 1994 and 2017, the earth lost more than 28 trillion tons of ice, and the rate of melt has only accelerated since then. All of the water projected to enter the ocean this century could drive sea levels up by several feet, displacing billions of people, while also disrupting fragile ecosystems in the polar regions and beyond.

Closely related to the cryosphere is the hydrosphere, the planet’s waterways, which have been overexploited and polluted by countries worldwide. Just one-third of the world’s rivers remain free-flowing, the rest dammed or otherwise disrupted. Although the earth still has an abundance of water, chronic misuse and abuse will lead to 3.6 billion people without safe access to it by 2050.  

The system most tied to the climate crisis is the atmosphere, the sky above you. In addition to being saturated with particulate matter, the atmosphere has grown increasingly thick with greenhouse gas emissions that trap heat on the earth’s surface. There are currently 420 particles of carbon dioxide per million particles in the atmosphere, the highest concentration for millions of years. 

The very term “greenhouse gas” refers to the “hothouse” effect seen in greenhouses, where temperatures climb much higher than the surrounding area. As the entire planet experiences this heating effect, all of the earth’s other systems are being disrupted, with increasingly disastrous outcomes.

For example, warming temperatures have rearranged global rain patterns, inundating some areas with floods of biblical proportions, while stripping other areas of all moisture. Similarly, warming temperatures are making it harder to get water (hydrosphere), melting the remaining ice caps (cryosphere), drying out soil (geosphere), and killing animal and plant life (biosphere). 

These impacts have cascading effects on public health, and disproportionately impact the world’s poorest and most marginalized communities that lack the wealth to adapt. Already, more than 13 million people die each year from climate impacts — and those are only deaths that can be clearly attributed. It’s likely that many more deaths can be tied to food and water shortages, and extreme levels of pollution — problems that will only get worse in the years ahead if we don’t take action. 

But the actions to stop this crisis are well-known and readily available. 

Planetary Health 

As the planet heals, so too does human health. 

But turning the planet into a source of continuous health will require transformative actions across human society and the development of new value systems, according to the Planetary Health Alliance and Indigenous leaders the world over. 

First and foremost, the fossil fuels that are heating up the planet need to be phased out and replaced with alternative sources of clean energy, while countries also work to increase energy efficiency in infrastructure worldwide. If countries can halve emissions by 2030, then the pathway to keep temperatures from rising more than 1.5 degrees Celsius above pre-industrial levels remains viable, and the worst aspects of the climate crisis can be avoided.

The health gains of transitioning beyond fossil fuels would be immediate in the form of cleaner air and water and less deadly heat waves.

The second major way to advance planetary health is by conserving and restoring wildlife, protecting 50% of the world’s land and marine environments from excessive human exploitation. Robust biodiversity provides humanity with food, clean water, clean air, and medicine, and shields human communities from natural disasters that would otherwise cause harm, according to the World Health Organization. 

The vast majority of humanity will live in cities by the middle of the century and planetary health advocates call for turning urban centers into wildlife refuges, full of green spaces, food production, and recreational opportunities. Many of the largest cities in the world are sites of extreme pollution due to an overreliance on gas-powered cars and little regulation of factories. By replacing cars with buses, bikes, trains, and ridesharing electric vehicles, cities can become healthier environments that ease rather than inflame asthma. 

Another way to improve both human and planetary health is by transforming food systems. Currently, the primary modes of food production worldwide — factory farms, industrial agriculture, trawling the ocean — are depleting and degrading wildlife and natural resources. These practices are guided by the pursuit of short-term gains, with little thought given to long-term resilience, and have no place in the future. 

By adopting regenerative forms of agriculture, countries can produce more food, while healing the planet’s forests, grasslands, and bodies of water. By creating global marine regulations, fish populations can rebound and thrive once again. And by adopting plant-based diets, the highly damaging model of factory farms can be phased out. 

In fact, scientists have even created a “planetary health” diet that, if broadly adopted, would ease stress on the planet, while also generating enough calories to feed all humans. 

The planet is remarkably resilient and can heal if humanity becomes a partner rather than foe. All human health and well-being stems from Earth, from the oxygen we inhale to the nutrients we consume to the water we drink to the medicines we ingest. And all of us have a role to play in championing the vision of planetary health.

“The moment we face calls for more than rapid innovation in our technologies and practices,” said Sam Meyers, the director of the Planetary Health Alliance. “Underneath the ecological crisis we have created and the global health crisis that it is precipitating, is a spiritual crisis."

He added: “We will need to weave a new fabric, with threads from Indigenous knowledge, the world’s faith traditions, literature, and the arts, that reasserts our spiritual connection to the natural world. Our story of human exceptionalism, of extraction, domination, and scarcity, and ultimately extinction, will need to give way to new stories and values of interdependence, equity, abundance, regeneration and renaissance.”