As the world’s attention turns toward the Amazon ahead of the 2025 United Nations climate summit in Belém, Brazil, new research is shining a spotlight on a truth Indigenous communities have known for generations: healthy forests are not just vital for biodiversity and climate—they are essential for human health. A sweeping, peer-reviewed study published in Communications Earth and Environment, part of the Nature Group, has found that forests managed by Indigenous peoples across eight Amazonian countries dramatically reduce the spread of 27 diseases, protecting millions from respiratory, cardiovascular, and infectious illnesses.
Led by the International Union for Conservation of Nature (IUCN), the study analyzed two decades of data from 1,733 municipalities—covering over 74% of the Amazon region in Bolivia, Brazil, Colombia, Ecuador, Peru, Suriname, Venezuela, and French Guiana. The findings are striking: municipalities closest to well-preserved Indigenous forests face significantly less risk from diseases linked to forest fires and those transmitted from animals and insects, such as malaria and Chagas disease. Between 2001 and 2019, nearly 30 million cases of fire-related, zoonotic, and vector-borne diseases were reported in the vast rainforest. The study’s lead authors argue that recognizing and enforcing Indigenous land rights is not just a matter of justice or conservation—it’s a public health imperative.
“Indigenous forests in the Amazon bring health benefits to millions,” said Paula Prist, Senior Programme Coordinator of the Forests and Grasslands Programme at IUCN. “We have long known that the rainforest is home to medicinal plants and animals that have cured countless illnesses. This study offers new evidence that forests themselves are a balm for fire-related threats to people’s lungs and hearts, to illnesses like Chagas, malaria and spotted fevers. Ensuring Indigenous communities have strong rights over their lands is the best way to keep forests and their health benefits intact.”
The study, titled “Indigenous territories can safeguard human health depending on the landscape structure and legal status,” drew on 20 years of data and focused on 21 fire-related diseases and six that are either zoonotic or vector-borne. The illnesses studied included Chagas disease, malaria, hantavirus, visceral and cutaneous leishmaniasis, and spotted fevers—diseases that disproportionately affect the Amazon’s 33 million inhabitants and for which cures are often difficult to access.
Forest fires, which are often intentionally set by illegal actors seeking to clear land for agriculture or cattle grazing, have become a particularly acute threat in the Amazon. According to the IUCN, exposure to smoke from these fires is directly linked to a surge in hospitalizations for respiratory and cardiovascular ailments. In the Brazilian Amazon alone, between 2002 and 2011, forest fires caused an average of 2,906 premature deaths each year from cardiopulmonary disease and lung cancer. “These fires fill the air with thick, choking smoke, sending droves to the hospital for respiratory ailments,” noted Ana Filipa Palmeirim, visiting professor at the Federal University of Pará and co-first author of the study. “As daily life comes to a complete standstill, children and the elderly must stay home to avoid hospital visits. Even when fires take place in remote forest areas, winds spread the pollution far and wide, creating deadly public health emergencies.”
The research adds to mounting evidence that Indigenous stewardship of land is a linchpin in the fight against climate change, biodiversity loss, and now, as the data reveal, the spread of disease. The study found that Indigenous territories consistently decrease disease incidence, but also highlighted that the health benefits are most pronounced when forest cover is maintained above 40%. This threshold, while debated by some external experts, underscores the importance of robust forest protection. Magdalena Hurtado, an anthropology and global health professor at Arizona State University, praised the study for its ambition but cautioned about the precision of the findings: “They claim that Indigenous territories only protect health when forest cover is above 40%. And so that that feels like, why 40%? Why not 35? Or why not a range? It doesn’t mean that the study is wrong, but it means that we need to be cautious because the patterns could change if different, more precise methods were used.”
Still, the consensus among scientists and Indigenous leaders is clear: the legal recognition and enforcement of Indigenous land rights is crucial not only for environmental reasons but for the health and well-being of millions. Francisco Hernández Cayetano, president of the Federation of Ticuna and Yagua Communities of the Lower Amazon (FECOTYBA), put it succinctly: “The ‘forest man’ or ‘man forest,’ according to the Indigenous perspective, has always been linked to the reciprocity between human health and the natural environment where one lives. If each state does not guarantee the rights and territories of Indigenous peoples, we would inevitably be harming their health, their lives, and the ecosystem itself.”
The timing of these findings is particularly significant. With the United Nations climate summit (COP30) scheduled for November 2025 in Belém, the so-called gateway to the Amazon, the role of Indigenous communities in climate action and conservation is expected to take center stage. As Julia Barreto, an ecologist and data scientist who contributed to the study, observed, “It is not only one country, and the whole world is depending on it somehow.” The research team, comprising scientists from multiple nations, aimed to make their data publicly accessible and to raise global awareness about the Amazon’s critical role in both environmental and human health.
External experts such as University of Washington health and climate scientist Kristie Ebi hailed the study as “impressive,” noting that it highlights the complex web of factors influencing human health and the vital role Indigenous communities play in shaping those outcomes. James MacCarthy, a wildfire research manager with the Global Forest Watch team at the World Resources Institute, echoed the sentiment, stressing that while Indigenous land tenure is essential, maintaining forest cover outside Indigenous-stewarded areas is also important to maximize health and environmental benefits.
Paula Prist, reflecting on the broader implications of the study, emphasized the need for balance: “It would be naive to suggest that all forest landscapes stay exactly as they are, especially with the land needs of farming and livestock production. The world needs landscapes that provide economic services, but also services that protect people’s health.”
As policymakers, activists, and scientists prepare to gather in Belém, the message from the Amazon is unambiguous: safeguarding Indigenous land rights and preserving forest cover are not just environmental issues—they are matters of life and death. The evidence is mounting, and the stakes could hardly be higher.