A brightly colored map of the world, covered in plants and flowers.

Healthy Planet, Healthy People

Promising solutions to our environmental crises are already making a difference. Now is the time to accelerate them.

By Dean Ellen J. MacKenzie, PhD ’79, ScM ’75

In the 1990s, Santiago, Chile, had an alarming wastewater problem. With less than 3% of the wastewater treated, the Mapocho River ran a steady stream of raw sewage through the center of the city. Hepatitis A, typhoid, and cholera outbreaks followed.

In 2000, the country hired a utility company to manage the wastewater treatment infrastructure and turn two wastewater treatment plants into “biofactories.” The plants generated renewable energy for surrounding homes (and the plants themselves), fertilizer for local fields, and clean water for irrigation. The process was economically self-sufficient and increased wastewater treatment to 100% by 2015. The river, once a place to avoid, is now surrounded by parks. 

More research is needed to fully understand the direct impact this made on disease rates, but the Mapocho River’s rebirth shows that when it comes to the future of our planet and our health, we can make positive change. 

In fact, many solutions are within our reach, according to Sam Myers, a leading thinker on the human health impacts of the accelerating disruptions to Earth’s natural systems. 

Planetary health is a relatively new term and new field, but it provides a powerful framework for transforming our relationship to our physical world. While it is concerned with climate change, planetary health is more broadly focused on the global health implications of the Earth crisis—all the ways that human activity is transforming our planet’s natural systems. This includes disruptions to biodiversity; the pollution of air, water, and soil; and changes in land use, such as deforestation and dams.

“The Earth crisis is at a scale where it’s essentially degrading our natural life support systems and that degradation is likely to drive a very large share of the global burden of disease of the next century,” Sam told me. “We can no longer think about public health without thinking about planetary health.” 

Consider: Since 1950, the human population has increased by more than 200%. We now use close to half of the planet’s livable surface to feed ourselves. We are driving species extinct at 1,000 times the historic rate. 

We see the effects on human health in everything from dams causing more schistosomiasis in West Africa to climate change fueling deadly extreme weather. Greater challenges are still to come. If rising temperatures reduce the capacity for physical labor in South Asia, where will people migrate to, and how might their movement fuel conflict? If rising carbon dioxide levels decrease the iron and zinc in crops, how many people will be driven into micronutrient deficiency? 

“We can no longer think about public health without thinking about planetary health.”

The work to reverse those trends will be daunting and complex, but my conversations with Sam left me surprisingly encouraged. When we look at the rapid shift to renewable energy, the rise of precision agriculture, or the creation of new meat substitutes, we see that human innovation is already making a difference. 

In 2016, Myers became the founding director of the Planetary Health Alliance, an international consortium of more than 380 universities, NGOs, and other organizations committed to addressing the impacts of global environmental change on human health and well-being. I am excited that the PHA is now housed at the Johns Hopkins University Bloomberg Center in Washington, D.C., and that Myers has joined the Bloomberg School and will work with colleagues from across the University to establish the Johns Hopkins Institute for Planetary Health, which will harness powerful cross-disciplinary expertise to confront these pressing challenges.  

Our School, and public health more broadly, is designed to think big, at population levels. Embracing planetary health is a natural step for scaling up our goals to build a world that is healthier, safer, more equitable—and sustainable. Having the Alliance and the Institute join our School will synergize some of our long-standing efforts. These include the Center for a Livable Future’s work to build a more equitable and resilient food system; the Center for Humanitarian Health’s efforts to respond to and prepare for climate-related and other emergencies; and the Center for Indigenous Health’s powerful cultural knowledge and other resources for creating a healthier planet. 

“What, globally, we do with this moment is going to determine how much suffering will follow,” Sam said. “But what better time for a world-class university to step into that space and accelerate the process, with research, with educating the world's leaders, with developing enlightened policy, with creating the new technologies?”

Our School will continue to explore new ways to bridge disciplines and collaborate with partners around Johns Hopkins to face the challenges ahead, both in pursuing new discoveries and interventions and in the vital work of implementation. From the pioneering research at the Morton K. Blaustein Department of Earth and Planetary Sciences in the Krieger School of Arts & Sciences to the SNF Agora Institute’s focus on nurturing global civic engagement, our University is positioned to push for large-scale, structural changes in how we live. 

We are at an inflection point when it comes to the health of our world. It is possible to look one way and see our failures, including frightening weather patterns, the loss of pollinating insects, and the trauma experienced by displaced communities. But it is possible to look the other way and see the promising solutions that scientists and policymakers are generating, as well as the growing groundswell of support for serious change. 

Over the course of 20 years, the Mapocho River was transformed from a sewage dump to a thriving urban wetland. If we act with urgency, we will be able to look back—decades from now—and see these types of environmental revivals all across the world. 

It’s vital that we see this vision not as a dream, but as a critical goal to work toward. We must achieve it to protect the health of future generations.