Home > Intersection of Human and Planet Health

Traditionally, the study of human health has focused on individual and collective groups, rather than outside forces. In recent years, however, we’ve seen the scope of nutrition expanded to include environmental components, with the introduction of new terms like “sustainable nutrition” and “planetary health.”

Prior to the COVID-19 pandemic, the global population was considered “healthier” than previous years, based on metrics including increased life expectancy, decreased child mortality and decreased global poverty levels. This “healthier” status was acknowledged by the Rockefeller Foundation-Lancet Commission on Planetary Health to be a direct result of increased use — and, in some cases, misuse — of resources such as energy and water use, deforestation and carbon dioxide emissions. While the impact of COVID-19 on this “healthier population” status is still largely unknown, a report from the Population Reference Bureau in August 2021 found that the current trajectory indicates a global population of 9.7 billion by 2050, a nearly 24% increase over 2020.

The growing population will put a greater strain on the ecosystem and resources, further contributing to climate change, which is observed through increased temperatures, rising sea levels and severe weather patterns. These factors impact human health, both directly and indirectly. “We can no longer separate the health of the environment from the health of humans.

Impact of Climate Change on Human Health and Nutrition:

Altered weather patterns directly affect yields and crop production, which along with non-climate factors, can impact the four pillars of food security: availability, access, utilization and stability. Displacement from homes, decreased access to resources such as health care and illness due to exposure to extreme temperatures can have long-term health consequences.

For example, the extreme drought in Ethiopia in 2016 caused widespread crop failure and resulted in nearly 10 million people requiring food aid. Similarly, in the U.S., 2021 brought Hurricane Ida to the Gulf Coast, killing an estimated 91 people. When the storm subsided, extreme heat followed, which was particularly dangerous given many had lost their homes or electricity in the hurricane. Widespread power outages left people with limited access to essentials including groceries, clean water and, in some instances, home health devices such as at-home dialysis.

The challenge of feeding more people using the current food systems poses a threat to biodiversity. For example, overfishing, which involves non-sustainable practices that deplete or endanger species, can result in biodiversity loss. Conversely, “the more variety of crops grown in one farming system, the more resilient that system is,” Purdy says. “The less biodiversity you have in an ecosystem, the more susceptible it is to pests, crop failure and soil degradation, including the soil microbiome; as we know, there is a significant connection between the soil microbiome and human gut microbiome.”

As more ecosystems and species become threatened, biodiversity will continue to decrease, which will impact the entire food chain. Each organism and species plays a role in the food chain; altering that chain will have a domino effect, which could impact human health in numerous ways, such as altering typical eating habits based on availability and in some cases resulting in nutrition insecurity, reducing gut microbiome and impacting the availability of some medicinal resources.

Inequities of Climate Change:

Climate change cannot be addressed in isolation — environmental justice must be part of the conversation. Environmental justice addresses how climate change disproportionately impacts groups and communities in underdeveloped and low-income regions. According to Greenpeace, environmental justice “acknowledges how privilege, power and oppression are integral to our understanding of how we are impacted by climate change and our environment.”

Role of Food Systems in Climate Change:

While greenhouse gas emissions are hard to quantify, the understanding that food systems contribute a significant portion of total global emissions is widely accepted. One study from 2015 estimated that food systems (production, processing, transportation, packaging, consumption and disposal) were responsible for about one-third of global carbon emissions, at 18 gigatons of carbon dioxide equivalent per year globally. That’s the equivalent of emissions from more than 3.5 billion passenger vehicles in a year. Another recent study indicates that production of animal-based foods accounts for about twice the amount of greenhouse gas emissions of plant-based foods.

Alternatively, alterations in temperature or weather patterns can impact crop growing cycles. Natural disasters such as droughts and floods can cause interruptions and sometimes destruction of crops and farming practices.

Sustainable and Equitable Policy Reform:

Legislation such as the Farm Bill, which is updated every five years, is one tool the U.S. is using to help support evolving food systems. The Farm Bill addresses agriculture and food programs including the Supplemental Nutrition Assistance Program and crop insurance for farmers.

Sustainability is a global problem and requires a global solution. The Paris Climate Agreement, adopted by 193 countries as of February 2022, is an international action plan to fight climate change and its negative impacts through a reduction in greenhouse gas emissions and slow the rate of global temperature increase to 1.5 degrees Celsius by 2050. However, a recent report indicates that without immediate and large-scale changes, it may already be too late to achieve this goal.

In November 2021, global leaders at the United Nations’ COP26 Climate Change Conference discussed progress toward the Paris Agreement’s framework and negotiated commitments and partnerships. The conference came on the heels of the UN Food Systems Summit, which focused on necessary transformation of food systems specifically to achieve the UN’s 17 Sustainable Development Goals by 2030. The goals are a framework to address health, inequality, economics and sustainability. Commitments at the summit included 150 organizations agreeing to green agriculture innovation and 45 nations promising policy reform.

Future of Food Systems:

As a direct result of the current stress on food systems, new innovative techniques and resources are arising, such as heat-resistant seeds, procurement and production methods that use fewer natural resources; developing cell-based meat; regenerative agriculture solutions that draw carbon out of the atmosphere to achieve net-zero emissions and more. Experts recommend following the lead of indigenous people, who manage a quarter of the Earth’s surface and preserve most of the remaining biodiversity.

We also can expect recommendations for food consumption to shift toward eating patterns that balance health and sustainability. Addressing this topic, the EAT-Lancet Report published in 2019 was the first full scientific review and recommendation for a healthy diet from a sustainable food system to support a future population of 10 billion people. However, these new approaches are not fool proof. The EAT-Lancet Report received criticism about assumptions and methods used to demonstrate noncommunicable disease mortality rates, the affordability of the diet and the impact a global implementation could have on people’s health and livelihoods, since the diet promotes a primarily plant-based eating pattern.

Individual Advocacy and Action:

Registered dietitian nutritionists are uniquely positioned to advocate for a more sustainable and equitable future. Those working in foodservice may think creatively about reducing food waste and packaging. Those in community settings can help people and communities grow and prepare their own food. Those in clinical and counselling settings may recommend ways for people to incorporate more plant-based options. Those in media and communications can use their platforms for strategic storytelling about human and planetary health.

“From planting that seed in the ground to how we grow and harvest the food or raise and slaughter the animal, to how we transport, store, distribute, process, package, prepare, consume and dispose of it — all of those parts of the food system have an impact on the environment, which have an impact on human health. “We can help dictate how all these processes occur to benefit both people and the planet.”

The Academy and its Foundation offer resources including the Future of Food Initiative; the Hunger and Environmental Nutrition dietetic practice group; the Food and Culinary Professionals DPG’s agriculture subgroup; Food System Sustainability: An Academy Advocacy Priority; Cultivating Sustainable, Resilient, and Healthy Food and Water Systems: A Nutrition-Focused Framework for Action; and the Revised 2020 Standards of Professional Performance for Registered Dietitian Nutritionists (Competent, Proficient and Expert) in Sustainable, Resilient and Healthy Food and Water Systems. Purdy also recommends Food and Planet, a dietitian-run organization, Planetary Health Collective and Johns Hopkins free Coursera courses on sustainable diets.

In addition to food waste reduction, people can advocate for a more sustainable and equitable future with their purchasing power. Buying from companies that have sustainable practices and commitments in place and shopping locally and seasonally can be great ways to make a difference. While these actions may seem small, if done at scale, they could largely affect overall greenhouse gas emissions and climate change, helping to protect both humans and the planet for years to come.

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