The world lost many conservationists, Indigenous leaders, and environmentalists in 2024.

Their lives were devoted to safeguarding the planet’s biodiversity, protecting vulnerable communities, and advocating for justice in the face of profound challenges. While each had a unique story, they shared a commitment to the environment, often working on the frontlines of conservation or battling entrenched systems of exploitation.

Not included here are the many brave conservation rangers who lost their lives in the line of duty—unsung heroes whose sacrifices ensure the continued survival of endangered species and ecosystems around the globe.

From towering figures like George Woodwell, who shaped the world’s understanding of climate change, to grassroots advocates like Nancy Wallace, who transformed urban landscapes into green sanctuaries, this list celebrates the extraordinary impact of these individuals. It remembers Ryan Killackey, whose documentary gave voice to the Amazon rainforest and its people, and Tuíre Kayapó, whose fearless leadership became a symbol of Indigenous resistance.

Their legacies remind us of the complexity and urgency of the global environmental crisis. Some, like Sumit Sen and Marian Newman, used science and activism to preserve wildlife; others, like Carlos Andrés Ascué Tumbo and Maria de Fátima Muniz, defended their ancestral lands with their lives.

Environmental stewardship often demands not only expertise and dedication but also immense courage. Their work endures as an inspiration to continue the struggle for a more verdant future.

Of course this is not a complete list. If there are people you feel should be included in this list, let Mongabay know.

Rabbi Ellen Bernstein, 70 (U.S.)

Rabbi Ellen Bernstein, a trailblazing environmentalist who integrated Jewish theology with ecological stewardship, died on February 27th at the age of 70.

In 1988, Rabbi Bernstein founded Shomrei Adamah (Keepers of the Earth), the first national Jewish environmental organization, linking ancient scriptural teachings to contemporary ecological concerns. Her work redefined the relationship between faith and environmentalism, emphasizing that Judaism inherently embodies ecological values. Through books such as Ecology & the Jewish Spirit (2000) and The Splendor of Creation (2005), she explored the biblical roots of environmental ethics, focusing on creation stories and the natural cycles described in Jewish texts.

Rabbi Bernstein’s vision extended beyond scholarship. She developed curricula, organized conferences, and wrote an ecological version of the Haggadah, The Promise of the Land (2020), to inspire deeper reflection on humanity’s responsibility to the earth. Her influence reached progressive congregations and academia alike, including her tenure as spiritual advisor at Hampshire College.

Her belief that science alone could not inspire ecological care led her to frame environmentalism as a spiritual imperative. As she wrote in 2024’s Toward a Holy Ecology, “The first step toward ecological repair is to love and identify with the natural world.”

Read more: New York Times

Chuck Bieler, 84 (U.S.)

Chuck Bieler, a transformative figure in wildlife conservation and former director of the San Diego Zoo, died on December 12th at the age of 84.

Bieler’s journey to the zoo began inauspiciously in the 1960s when, with no prior experience in wildlife, he joined the San Diego Zoo to lead group sales. Over the decades, he rose through the ranks, becoming a leader known for his indefatigable advocacy for wildlife conservation.

Under his guidance, the San Diego Zoo expanded its mission from a local attraction to a globally recognized institution for wildlife conservation and research. Bieler was instrumental in developing the Safari Park and fostering partnerships that advanced species recovery programs, including efforts to protect the California condor and African elephants.

A recipient of the Association of Zoos and Aquariums’ R. Marlin Perkins Award for Professional Excellence in 2016, Bieler was celebrated for his ability to inspire collaboration among conservationists, legislators, and the public. His leadership extended beyond the zoo, as he championed environmental education and advocated for stronger protections for endangered species.

Bieler’s legacy is encapsulated in Heart of the Zoo, a 2022 biography detailing his remarkable career.

Read more: San Diego Union Tribune

Joseph E. Bodovitz, 93 (U.S.)

Joseph Bodovitz, a leader in environmental regulation and public policy, passed away on March 9th at the age of 93. Over four decades, he played a central role in shaping California’s approach to conservation, leaving an indelible mark on the San Francisco Bay, the state’s coastline, and beyond.

Born in Oklahoma City in 1930, Bodovitz pursued journalism after earning degrees from Northwestern and Columbia. A reporter at the San Francisco Examiner, he covered urban development, honing the skills that would later define his career in public service. In the 1960s, his work at the San Francisco Planning and Urban Research Association (SPUR) led to his appointment as study director of the San Francisco Bay Conservation Study Commission. The resulting Bay Plan became a landmark guide for balancing development with conservation, and in 1965, Bodovitz was named the founding executive director of the San Francisco Bay Conservation and Development Commission (BCDC).

His success at BCDC set the stage for his leadership of the California Coastal Commission, established in 1972 to protect the state’s 1,100-mile coastline. Later, as executive director of the California Public Utilities Commission and president of the California Environmental Trust, he tackled issues ranging from utility deregulation to regional planning.

Read more: Legacy.com obituary

Christophe Boesch, 72 (U.S.)

Christophe Boesch, a pioneering primatologist whose studies of chimpanzees revealed their cultural complexity and underscored the urgency of their conservation, died on January 14th, at the age of 72.

Boesch began his career in Côte d’Ivoire’s Taï National Park in 1979, establishing the first long-term study of wild chimpanzees in a rainforest. His work there, alongside his wife Hedwige Boesch-Achermann, uncovered groundbreaking behaviors, including the use of tools to crack nuts and cooperative hunting strategies. Unlike previous studies in savannah habitats, Boesch’s research in the dense forest provided a richer understanding of chimpanzee social structures and ecological adaptations.

As director of the Department of Primatology at the Max Planck Institute for Evolutionary Anthropology, Boesch expanded the study of chimpanzee cultures across Africa, demonstrating how human activities erode these traditions. His ambitious projects linked primate behavioral diversity with conservation, advocating that preserving chimpanzee cultures required safeguarding their habitats.

In 2000, Boesch co-founded the Wild Chimpanzee Foundation, which spearheaded the creation of protected areas, including Guinea’s Moyen-Bafing National Park. He lobbied industries and governments, often facing bureaucratic and corporate resistance with unrelenting determination.

Boesch’s legacy endures in the forests of West Africa, where his work has ensured that the behaviors and habitats of chimpanzees continue to be studied, celebrated, and protected.

Read more: Nature

David Bonderman, 82 (U.S.)

David Bonderman, who died on December 11th at the age of 82, was best known as a titan of private equity, acclaimed for turning undervalued companies into lucrative ventures. Over decades, his sharp instincts and strategic acumen at TPG—formerly Texas Pacific Group—yielded control of firms as diverse as Continental Airlines, J. Crew, and Petco. His successes made him a billionaire, but his lesser-known legacy lay far from corporate boardrooms, amidst the savannas and forests of Africa.

Through The Wildcat Foundation, Bonderman invested tens of millions of dollars into wildlife conservation, with an emphasis on addressing elephant ivory and rhino horn trafficking. His philanthropy supported anti-poaching initiatives, leveraged technology to aid rangers, and backed efforts to create sustainable livelihoods for communities living alongside wildlife. For Bonderman, effective conservation required addressing the intertwined fates of animals and humans.

His approach was pragmatic, focusing on scalable solutions. Under his aegis, drones monitored vast parks, and resources flowed into training rangers. Yet, he acknowledged the limits of technology alone, emphasizing that conservation was fundamentally about people. During the pandemic, when tourism-dependent safari operations faltered, his investments ensured employees stayed on payroll and conservation efforts continued—a reflection of his commitment to long-term thinking in protecting nature.

Read more: David Bonderman: The Investor Who Championed Conservation

Albert K. Butzel, 85 (U.S.)

Albert K. Butzel, a lawyer whose strategic brilliance shaped the fight to protect the Hudson River’s natural integrity, died on January 26th at the age of 85. His legal career was defined by two landmark victories: the defeat of the Westway highway project in Manhattan and the halt of a hydroelectric plant at Storm King Mountain. These triumphs not only preserved the Hudson’s ecosystem but also established legal precedents in environmental law.

Butzel’s pivotal role in the Westway battle—an ambitious $4 billion landfill and highway project—exposed environmental impact misrepresentations that would have devastated the striped bass nursery in the river. His work culminated in the project’s cancellation in 1985, redirecting federal funds to bolster New York’s transit system. Similarly, his efforts against the Storm King power plant safeguarded the Hudson Highlands and catalyzed the recognition of citizen standing in environmental lawsuits.

Beyond litigation, Butzel championed the transformation of Manhattan’s neglected waterfront into Hudson River Park, a greenway now cherished by millions.

Read more: New York Times

Adriana Casas, 53

Adriana Casas Isaza, an advocate for biodiversity and environmental policy, died on December 17th, aged 53. Hers was a life devoted to safeguarding nature and mentoring the next generation of environmental stewards.

Born in Chicago and raised in Bogotá, Colombia, Ms. Casas studied law at the Universidad de Los Andes, graduating in 1994, and later earned a degree in environmental policy from Yale University’s School of Forestry and Environmental Studies. Her career began at Colombia’s Ministry of the Environment, where she co-authored one of the first comprehensive texts on genetic resource access and benefit-sharing, aligning with the objectives of the United Nations Convention on Biological Diversity.

Ms. Casas’s legacy includes co-founding the fondo de becas Colombia Biodiversa, a scholarship fund established as a wedding gift with her husband, Cristián Samper. Administered by the Fundación Alejandro Ángel Escobar, the fund has supported 175 Colombian students in biodiversity research, embodying her vision for sustainable conservation.

Throughout her life, Ms. Casas held various influential roles, including as a fellow at Conservation International and a board member of Nature and Culture International. Her work on the environmental impacts of illegal mining in the Amazon highlighted her dedication to protecting vulnerable ecosystems.

Read more: Green Cremation Obituary

Jimmy Carter, 100

James Earl Carter Jr., the 39th president of the United States, died on Sunday at his home in Plains, Georgia. He was 100 years old.

Known to the world as Jimmy Carter, his presidency was marked by foresight, humility, and an enduring commitment to the environment that would define his legacy long after he left the White House.

While his tenure lasted only a single term, Carter’s achievements in conservation and environmental stewardship were monumental. Chief among these was the passage of the Alaska National Interest Lands Conservation Act (ANILCA) in 1980, a law that protected 157 million acres of pristine wilderness. This sweeping legislation doubled the size of the National Park System and created a constellation of parks, wildlife refuges, and conservation areas. For Carter, ANILCA was not just policy; it was deeply personal. He later described it as one of the proudest accomplishments of his life, a sentiment echoed by conservationists who hailed it as an unparalleled victory for the natural world.

Carter’s environmental vision was not confined to Alaska. He established the Chattahoochee River National Recreation Area in Georgia, safeguarded wilderness areas across the Western United States, and championed the Surface Mining Control and Reclamation Act, curbing the environmental damage of strip mining. Yet perhaps his most prophetic contribution was the Global 2000 Report, a document warning of the catastrophic consequences of unchecked fossil fuel dependence and biodiversity loss. Written decades before climate change became a central political issue, it underscored his ability to see beyond the immediate pressures of the presidency to the existential challenges of the planet.

Carter’s environmental ethos was rooted in a belief that nature’s riches were not boundless. He appointed James Gustave Speth, a co-founder of the Natural Resources Defense Council, to educate him on emerging environmental threats, including acid rain and carbon emissions. Carter’s installation of solar panels on the White House roof symbolized his aspiration for a cleaner, renewable energy future—a vision thwarted by political tides but vindicated by history.

In retirement, Carter’s environmental activism endured. Through his work with the Carter Center, he continued to champion human rights, global health, and environmental preservation. His voice, often modest yet resolute, inspired a generation to view conservation as both a moral duty and a civic responsibility.

Jimmy Carter may have hailed from a small town in Georgia, but his impact on the planet was vast. He leaves behind a legacy of preserved wilderness, a call to environmental action, and a reminder that leadership, at its best, is rooted in stewardship.

Read more: Rolling Stone

Chhoeung Chheng, 63 (Cambodia)

In the gathering dusk of December 4th, Chhoeung Chheng, a Cambodian journalist with a dogged commitment to exposing illegal logging, was shot near Beng Per Wildlife Sanctuary. He succumbed to his injuries three days later.

Chheng, 63, had been no stranger to peril. For five years, he chronicled the relentless destruction of Cambodia’s forests for Kampuchea Aphiwat News, undeterred by the threats against him. On that fateful evening, alongside his colleague, Moeun Ny, Chheng was documenting the shadowy trade that has gnawed away 72% of Beng Per’s primary forest cover over two decades. Their presence provoked the ire of a tractor-riding logger, who gunned him down.

His death marked the first killing of a Cambodian journalist since 2014, yet it felt less an anomaly than a continuation of a grim pattern. Environmental reporters around the world continued to be silenced, their work seen as a threat by both state and private actors.

Cambodia’s forests lost a defender that evening. The world lost a voice, silenced for daring to seek the truth.

Read more: Cambodia’s forests lost another defender | Environmental journalist in Cambodia shot and killed by suspected logger

Simon Cowell, 72 (U.K.)

Simon Cowell, the founder of the Wildlife Aid Foundation (WAF) and host of the long-running television series Wildlife SOS, died on October 29th. A former broker in London, Cowell turned a backyard passion for rescuing animals into a career dedicated to rehabilitating injured and orphaned wildlife.

Cowell began his work in the early 1980s, rescuing animals from his home in Surrey. By 1987, his efforts had grown into a formal charity, the Wildlife Aid Foundation, which provided care for countless species and became a hub for conservation education. Through Wildlife SOS, Cowell brought the challenges of wildlife rehabilitation to millions, combining humor and candor to advocate for often-overlooked species.

A tireless campaigner for wildlife, Cowell was awarded an MBE in 2005 for his contributions to conservation. He also launched iDot (I Do One Thing), an initiative encouraging individuals to take small, daily actions to benefit the environment.

Read more: BBC

Frans de Waal, 75 (U.S.)

Frans de Waal, a primatologist whose research into animal cognition and behavior challenged human exceptionalism, died on March 14th at his home in Stone Mountain, Georgia. He was 75.

Born in the Netherlands, de Waal earned his Ph.D. in biology from Utrecht University in 1977 and began his career studying chimpanzees at the Arnhem Zoo. His early work, including his 1982 book Chimpanzee Politics, revealed the complex social strategies of primates, drawing parallels to human political behavior. The book gained cultural significance when then-House Speaker Newt Gingrich recommended it to new members of Congress.

De Waal’s research demonstrated that primates exhibit reconciliation, empathy, fairness, and cultural transmission—traits once considered uniquely human. His 2003 experiment with capuchin monkeys, where inequitable rewards led to protests, became a viral illustration of animals’ sense of justice.

At Emory University, where he directed the Living Links Center, de Waal expanded his studies to bonobos and other primates, advocating for their similarities to humans. His work popularized terms like “alpha male” and challenged the idea of anthropomorphism, arguing instead against “anthropodenial,” the refusal to acknowledge shared traits between humans and animals.

Through his bestselling books, including Are We Smart Enough to Know How Smart Animals Are?, de Waal brought scientific insights to global audiences, reshaping public understanding of animal behavior. His career bridged science and storytelling, offering a profound reexamination of humanity’s place in the natural world.

Read more: New York Times

Dingo Dinkelman, 44 (South Africa)

Graham “Dingo” Dinkelman, a charismatic wildlife presenter and conservationist who captivated audiences with his daring work with venomous snakes and his passionate advocacy for African wildlife, died on October 28th, following complications from a green mamba bite. He was 44.

Born in Pietermaritzburg, South Africa, Dinkelman owned and operated Dingo’s Farm and Reptile Park in KwaZulu-Natal. With a natural flair for storytelling, he turned his fascination with wildlife into an educational mission, reaching millions through his YouTube channel and Discovery Channel appearances. Often compared to the late Steve Irwin, Dinkelman balanced thrilling encounters with an enduring message of conservation and reverence for nature.

His videos showcased high-stakes interactions with venomous snakes, crocodiles, and other dangerous animals, but they also highlighted critical conservation efforts. Dinkelman worked on dehorning rhinos to deter poaching, collaring elephants for monitoring, and relocating predators like lions to ensure ecological balance.

“My purpose,” he once said, “is to help people connect with animals, to inspire those who have never experienced nature to become advocates for wildlife.”

Read more: NBC News

Peter Dykstra, 67 (U.S.)

Peter Dykstra, a journalist whose sharp wit and tenacity brought environmental issues to the forefront of mainstream media, died on July 31th in Atlanta at the age of 67.

A pioneer in environmental journalism, Dykstra began his career in activism as the U.S. media director for Greenpeace, where he honed his ability to capture attention for urgent environmental causes. Transitioning to journalism, he joined CNN in 1991, where he rose to senior executive producer of the science, technology, and environment unit. His team earned accolades, including an Emmy and a Peabody, for coverage of events like Hurricane Katrina and the Indian Ocean tsunami.

At CNN, Dykstra was an early advocate for accurate reporting on climate change, challenging newsroom norms that gave undue weight to climate deniers. His efforts helped shift the narrative, though he often lamented the industry’s reluctance to fully embrace the science.

In 2008, after CNN disbanded his unit, he became the publisher of Environmental Health News and The Daily Climate, where he continued to mentor journalists and amplify underreported stories. Even as health challenges confined him to a wheelchair in later years, he remained a vital voice on the public radio program Living on Earth.

With humor and unwavering commitment, Dykstra transformed complex environmental issues into stories that educated and inspired.

Read more: Mongabay | New York Times 

Ross Gelbspan, 84 (U.S.)

Ross Gelbspan, a dogged journalist and relentless voice for climate truth, passed away on January 27th, at the age of 84. A former editor and reporter for newspapers including The Boston Globe and The Washington Post, Gelbspan redirected his talents late in his career to uncovering the deliberate efforts of fossil fuel interests to undermine climate science and policy.

Born in Chicago in 1939, Gelbspan earned his B.A. at Kenyon College and began a distinguished three-decade career in journalism. At The Boston Globe, he conceived and edited a Pulitzer Prize-winning series on racial discrimination in employment. His investigative work also included exposing domestic abuses tied to the Iran-Contra affair and chronicling Soviet dissidents during the Cold War.

In retirement, Gelbspan turned his focus to climate journalism, publishing The Heat Is On (1997) and Boiling Point (2004). These books laid bare the fossil fuel industry’s campaigns of denial and delay, galvanizing a generation of activists and inspiring the creation of DeSmog, a leading platform for exposing climate disinformation.

Gelbspan’s contributions reached beyond his writing. He spoke globally, from Oxford to the World Economic Forum, and mentored many in the fight against climate inaction.

Read more: DeSmog

Elva Gemita, 44 (Indonesia)

Elva Gemita, a steadfast advocate for wildlife and forest conservation in Indonesia, passed away on November 24th at the age of 44.

Born and raised near Kerinci Seblat National Park, she developed an early connection with the biodiversity that would define her life’s work. Her career began in the forests of Jambi Province, dismantling illegal animal traps and conducting wildlife surveys. This unglamorous but vital fieldwork typified her approach: methodical, grounded, and unyielding.

By the mid-2000s, she was immersed in tiger monitoring programs at the Zoological Society of London (ZSL), building the expertise that would underpin her later contributions to the survival of the Critically Endangered Sumatran tiger.

Her work was not confined to cataloging loss. At Hutan Harapan, one of Indonesia’s largest ecosystem restoration projects, Elva served as Head of Environment, Research, and Development. Here, she helped turn 100,000 hectares of degraded rainforest into a living laboratory for conservation.

Elva was instrumental in creating Forum Harimau Kita, a national tiger conservation network. She trained the next generation of conservationists, instilling in them the discipline and resolve she embodied.

Her passing leaves a void not just in the conservation community but in the forests she sought to protect. Elva Gemita’s legacy is one of enduring dedication—an example of how one life, lived with purpose, can shape the fate of a species and the land it calls home.

Read more: Obituary for Indonesian conservationist Elva Gemita

Victorio Dariquebe Gerewa, 61 (Peru)

Victorio Dariquebe Gerewa met a tragic end on April 19th in Kosñipata, Cusco, Peru. A devoted guardian of the Amarakaeri Communal Reserve, his life’s work was the defense of one of the Amazon’s most threatened ecosystems. Returning home to his community of Queros on a motorbike alongside his 18-year-old son, Gerewa was ambushed by unknown assailants who fatally shot him in the chest with a shotgun. His son, though beaten and restrained, managed to escape the attack.

Gerewa, a member of the Harakbut people, was no stranger to danger. His role as a park ranger placed him on the frontlines of combating illegal mining, deforestation, and narcotrafficking—forces that have long plagued the Amazon. Escalating threats against him suggest his murder is tied to these illicit industries.

For nearly a decade, Gerewa served with the Amarakaeri reserve, courageously reporting on illegal activities encroaching on the protected area. His commitment to safeguarding the forest extended beyond enforcement; he carried the wisdom of his ancestors and an unyielding dedication to his people and the environment.

His death marked the 34th environmental defender slain in Peru since 2013, underscoring the peril faced by those who dare to protect nature in one of the world’s most biodiverse regions.

Read more: Ojo Publico obituary

Matthew Gompper (U.S.)

Matthew Gompper, a wildlife ecologist and Head of the Department of Fish, Wildlife, and Conservation Ecology at New Mexico State University, died on March 26th. His career spanned decades of research on mammals, wildlife diseases, and the intricate dynamics of ecosystems across the globe.

Born in New York, Gompper’s academic journey spans several roles before he joined New Mexico State University in 2019. Along the way he developed a reputation for intellectual rigor, collaborative spirit, and an unrelenting curiosity about the natural world.

Gompper’s research took him from the Adirondacks of New York to the grasslands of India, the Brazilian Pantanal, and the Terai of Nepal. His work examined how resource subsidies shape predator populations, how parasites interact with their hosts, and how species distribution is influenced by ecological pressures. He was particularly known for his studies on feral dogs and their ecological impacts.

A mentor, scholar, and adventurer, Gompper left behind a legacy of scientific contributions and global fieldwork, enriching the field of wildlife ecology.

Tulsi Gowda, 86 (India)

Tulsi Gowda, a revered environmentalist and Padma Shri awardee, was known as the “Encyclopedia of the Forest,” her deep knowledge of native flora and unwavering commitment to conservation earned her admiration from local and national communities alike.

Born into the Halakki tribe in rural Karnataka, Tulsi lost her father at the age of two and began working alongside her mother as a laborer in a forest nursery. Despite lacking formal education, she became an authority on forest ecosystems, planting over 30,000 saplings and contributing to reforestation efforts over a career spanning more than six decades with the Karnataka Forest Department. Her ability to identify mother trees and collect seeds at optimal germination periods was unmatched.

In 2021, Tulsi was awarded the Padma Shri, India’s fourth-highest civilian honor, recognizing her lifelong dedication to nurturing forests. Beyond her work with trees, she actively mentored children in her village, imparting her knowledge of the natural world and its conservation.

Tulsi’s contributions extended to social causes, where she stood as a defender of women’s rights within her community. Her life’s work left an indelible mark on Karnataka’s landscapes and its people.

Read more: Hindustan Times

Marty Griffin, 103 (U.S.)

Loyal Martin Griffin Jr., 103, a tireless advocate for California’s coastlines and waterways, died on May 22th. Known to many as Marty, he was instrumental in preserving the Marin-Sonoma coast, protecting vast swathes of land and ensuring their natural beauty for future generations.

Born in 1920 in Utah and raised in California, Griffin was a physician by training but found his life’s calling in conservation. In the 1960s, he emerged as a leader in thwarting ambitious development plans that threatened the North Bay landscape. He played a central role in saving Bolinas Lagoon, Richardson Bay, and Tomales Bay, often employing strategic land acquisitions and deft political maneuvering.

Griffin’s efforts extended to derailing a proposed freeway through Marin and Sonoma and halting the construction of a nuclear power plant at Bodega Bay. His book Saving the Marin-Sonoma Coast chronicled these battles, leaving a blueprint for future conservationists.

As a founder of Audubon Canyon Ranch, he secured critical habitats, including the heron and egret nesting grounds that captivated him as a boy. His leadership also helped establish the Environmental Forum of Marin, training advocates to continue the work he began.

A relentless and effective campaigner, Griffin was as uncompromising in his defense of nature as he was generous in mentoring others. His preserved landscapes stand as testaments to his vision and determination.

Read more: Press Democrat

Karsten Heuer, 56 (Canada)

Karsten Heuer, a conservationist whose work spanned from the Canadian Rockies to the Arctic tundra, died on November 5th, at the age of 56. His career blended science, adventure, and advocacy, leaving a lasting impact on wildlife conservation and ecological restoration.

Heuer began his journey as a Parks Canada warden, where his early tracking studies influenced wildlife corridors in Banff, significantly increasing wolf activity in the area. This foundational work propelled him into the large-landscape-scale conservation movement, advocating for interconnected ecosystems rather than isolated reserves.

In the late 1990s, Heuer undertook a 3,400km trek from Yellowstone to Yukon, embodying the principles of the Yellowstone to Yukon Conservation Initiative, which he later led. His account, Walking the Big Wild, became a celebrated work of conservation literature.

In 2003, Heuer and his wife, Leanne Allison, followed the Porcupine caribou herd for 1,500km across Alaska and the Yukon, documenting the journey in the award-winning film Being Caribou. He later spearheaded the ambitious reintroduction of bison to Banff National Park, restoring a species absent for 140 years.

Read more: Explorers Web

AJT Johnsingh, 77 (India)

A.J.T. Johnsingh, a pioneering Indian wildlife biologist and conservationist who devoted his life to understanding and preserving the country’s natural heritage, died on June 7 at the age of 77.

Johnsingh’s contributions to wildlife science and policy were vast, spanning decades of field research and mentorship. As Dean of the Faculty of Wildlife Sciences at the Wildlife Institute of India (WII), he trained hundreds of forest officers and biologists, fostering a generation of conservationists. His work encompassed a range of species, from the iconic Asian elephant to the elusive Nilgiri tahr, and his field studies were instrumental in shaping conservation strategies.

Known for his boundless curiosity and unmatched energy, Dr. Johnsingh was a relentless advocate for field-based conservation. His ability to transform the jungle into a classroom and vice versa left a lasting impression on his students. His research, which included over 70 scientific papers and 80 popular articles, significantly influenced wildlife management policies across India.

Read more: Mongabay-India

Tuíre Kayapó, 57 (Brazil)

Tuíre Kayapó, a fearless environmentalist and Indigenous leader whose iconic protest against the Belo Monte Dam in 1989 galvanized global attention to the rights of Brazil’s Indigenous peoples, died on August 10 at 57. Her death, attributed to uterine cancer, marks the end of a remarkable life of advocacy for her people and the Amazon rainforest.

Born in Kokrajmoro, deep in the Kayapó Indigenous Territory, Tuíre emerged as a leader at a young age. In 1989, at just 19, she confronted Eletronorte officials at the First Meeting of Xingu Indigenous Peoples in Altamira, Pará, wielding a machete to symbolically challenge the company’s plans for the Kararaô (later Belo Monte) Hydroelectric Plant. Her dramatic gesture, immortalized in photographs, delayed the dam’s construction for two decades.

Over the years, Tuíre expanded her activism, addressing Congress, speaking at international forums, and opposing destructive projects such as mining on Indigenous lands and legislation limiting Indigenous territorial claims. In 2019, she co-organized Brazil’s first March of Indigenous Women, amplifying the voices of women in the Indigenous rights movement.

As one of the first women chiefs in the Kayapó community, Tuíre’s leadership inspired generations. She worked tirelessly to protect the Amazon’s ecosystems, declaring that “the rivers, the forests, the Indigenous peoples—it is their survival I defend.”

Read more: Brasil de Fato | ISA

Gerardo Keimari Enrique, 25 (Peru)

Gerardo Keimari Enrique, a Matsiguenka leader, was found dead on October 7 in the Madre de Dios River near his community’s territory, amid escalating violence against Indigenous defenders.

His death came just months after AIDESEP, an organization representing the Indigenous peoples of the Peruvian Amazon, declared a state of emergency in July following the murder of another leader, Mariano Asacama.

Keimari had been leading efforts to expand his community’s land title, facing imminent threats from illegal mining and drug trafficking. Members of the Shipetiari community had reported gunfire and death threats to Peruvian authorities. Despite these warnings, Keimari was murdered, exposing a failure in the government’s protective measures. His death adds to a growing list of Indigenous leaders who have lost their lives defending Amazonian territories.

Read more: SPDA (Spanish) | Amazon Watch

Bob Kennedy, 76 (U.S. / Philippines)

Robert “Bob” Kennedy, an ornithologist and conservationist whose work spanned continents, passed away on July 20th, at the age of 76. Known for his tireless dedication to avian conservation, Kennedy made an indelible mark on wildlife preservation, particularly in the Philippines.

Kennedy first arrived in the Philippines in 1972 as a Peace Corps volunteer, where he collaborated with the Philippine Parks and Wildlife Office to establish a conservation program for the critically endangered Philippine Eagle. His efforts helped transform the fledgling “Monkey-eating Eagle Conservation Program” into the Philippine Eagle Foundation, now a cornerstone of global avian conservation. He also played a pivotal role in renaming the species to “Philippine Eagle,” a change symbolizing national pride and ecological awareness.

A prolific researcher, Kennedy co-authored the definitive Guide to the Birds of the Philippines (2000), a landmark work that cataloged the nation’s rich avian biodiversity. His field expeditions yielded the discovery of numerous new species, further cementing his legacy in conservation science. Beyond his work in the Philippines, Kennedy championed the protection of wetlands and water habitats in New England, where he inspired community-driven conservation initiatives.

Read more: Legacy.com obituary

Ryan Patrick Killackey, 46 (U.S.)

Ryan Patrick Killackey, who died at 46 on October 4th, was a man of singular purpose. Born in Homewood, IL, he grew up with a fascination for nature that would eventually drive him to the farthest reaches of the Amazon. But his journey was no simple adventure; it was defined by hardship, loss, and a fierce dedication to preserving the natural world and its people.

It was in the verdant heart of Yasuni National Park in the Ecuadorian Amazon that his life found its true direction. This was a place where nature’s abundance defied comprehension: a single hectare held more tree species than the entire continental U.S. Yet this sanctuary was threatened, not by nature’s hand, but by the insatiable thirst for oil buried deep below.

When Ryan arrived in Ecuador, he went not only as a biologist but also as an artist, with a camera slung over his shoulder and a mission to chronicle the fragility of what he encountered. His work soon became more than a job; it grew into a seven-year labor of love and perseverance: his documentary, Yasuni Man.

The film brought into sharp focus the struggle of a people and a forest, capturing the spirit and anguish of a community besieged by industry. In 2023, the film’s impact helped sway the tide. Ecuadorians voted to end oil drilling in Yasuni—a victory that, though small and bittersweet for Ryan, who was by then weakened by illness, brought some solace.

His life’s work reminds us that even when faced with overwhelming odds, there is value in bearing witness. For Ryan, the rainforest was not simply a subject for his lens; it was a living entity, breathing, enduring, and longing to be seen.

Read more: The life and legacy of Ryan Killackey, the filmmaker who rallied international support for Yasuni (Obituary)

Estella Bergere Leopold, 97 (U.S.)

Estella Bergere Leopold, a pioneering botanist whose study of ancient pollen shed light on climate change and whose activism preserved natural treasures like the Florissant Fossil Beds and Mount St. Helens, died on February 25th in Seattle. She was 97.

The youngest child of Aldo Leopold, a titan of 20th-century ecology, Estella forged her own path while championing her father’s ethos of land stewardship. Trained as a palynologist, she studied fossilized pollen to reconstruct ancient climates, revealing how ecosystems evolved in response to environmental shifts. Her early research demonstrated how plants adapted to fluctuating conditions, insights that profoundly shaped the understanding of modern climate change.

In the 1960s, Leopold led efforts to save Colorado’s Florissant Valley from suburban sprawl. As a founder of the Defenders of Florissant, she combined grassroots advocacy and legal action, resulting in the creation of Florissant Fossil Beds National Monument in 1969. Later, at the University of Washington, she turned her attention to seismic research and successfully campaigned to protect Mount St. Helens after its eruption.

Leopold’s environmental legacy extended to the Aldo Leopold Foundation, which she co-founded in 1982 to preserve her father’s work and advance ecological awareness.

Read more: New York Times

Donald Lindburg, 91 (U.S.)

Donald Lindburg, a trailblazing conservationist whose work spanned continents and species, died on December 14th at the age of 91. From modest beginnings in Depression-era South Dakota and Montana, he forged a path that revolutionized the care and preservation of wildlife, notably cheetahs and giant pandas, at the San Diego Zoo.

Lindburg began his career studying anthropology, which led him to observe rhesus macaques in India and primates in Borneo. He joined the San Diego Zoo in 1979, where his behavioral research brought transformative change. His innovative approach to cheetah breeding—including introducing lure-chasing to mimic natural hunting behaviors—led to record-setting reproduction rates, establishing the zoo as a leader in cheetah conservation.

In 1996, Lindburg was tasked with leading the zoo’s Giant Panda Project. Under his guidance, Hua Mei, the first surviving giant panda cub born in the United States, arrived in 1999, captivating a nation and igniting “Pandamania.” His efforts extended globally, fostering collaborations with China to bolster panda conservation.

Throughout his life, Lindburg promoted naturalistic enclosures to ensure animals’ psychological well-being. He retired in 2006, but his legacy endures in the thriving populations and conservation programs he helped shape.

Read more: Legacy.com obituary

Juan López, 46 (Honduras)

Juan López, 46, a courageous defender of Indigenous lands and environmental rights, was assassinated on September 14th in Tocoa, Honduras. His murder, outside a church where he had attended Mass, highlighted the dangers of environmental activism in one of the world’s most dangerous countries for environmental defenders.

Born in Tocoa, López was deeply rooted in his community. As a leader of the Municipal Committee for the Defense of Common and Public Goods, he fought against open-pit iron oxide mining in the Carlos Escaleras National Park, a protected area vital to the Lenca Indigenous community for its water, forests, and biodiversity. His work often put him at odds with powerful local and national interests, including politicians and corporations tied to the mining industry.

In 2019, López was awarded the Letelier-Moffitt Human Rights Award in Washington, D.C., in recognition of his efforts to protect the Guapinol and San Pedro rivers. Despite international accolades, he faced constant threats, prompting protection measures from the Inter-American Commission on Human Rights.

López’s death was widely condemned, including by Pope Francis and human rights organizations. His legacy lives on in the forests and rivers he sought to protect, and in the determination of those who continue his fight.

Read more: American Magazine | AP News

Maria de Fátima Muniz, 52 (Brazil)

Maria de Fátima Muniz, known to her people as Nega, a spiritual leader and defender of Indigenous land rights, was fatally shot on January 21th in Bahia, Brazil. She was 52.

Born into the Pataxó Hã-Hã-Hãe community, Maria dedicated her life to preserving the traditions and lands of her ancestors. A midwife and community organizer, she guided her people through prayer, song, and ritual. She held her maracá—a ceremonial rattle—in her hands as she fell, a testament to her dedication to her culture.

Maria’s death occurred during a violent clash over land rights in Caramuru-Catarina Paraguassu, part of her community’s ancestral territory. Alongside her brother, Chief Nailton Muniz, she led efforts to reclaim the land, planting crops and asserting their rightful ownership. Their actions were met with hostility from armed landowners, allegedly supported by members of the Bahia Military Police. The confrontation resulted in Maria’s death, drawing international attention to violence against Indigenous activists.

Maria’s life was marked by a steadfast commitment to justice. She represented her people at political forums and organized cultural exchanges to amplify Indigenous voices. Her legacy endures in the forests her community has restored and the lives she touched. “She has become a legend for our people,” her nephew, Mukunã, said. “Her spirit remains in our songs, rituals, and every step of our journey.”

Read more: Al Jazeera

Marian Newman, 80 (U.S.)

Marian Newman, an advocate for wildlife conservation who championed the protection of species as diverse as kangaroos, whales, and elephants, died on October 30th. She was 80.

Born in Rochester, New York, Newman’s early life was steeped in activism. Her upbringing in a socially conscious household laid the foundation for her lifelong commitment to environmental justice. In the early 1970s, her efforts to save kangaroo populations in Australia earned her the moniker “The Kangaroo Lady.” Her work helped secure endangered species status for two kangaroo species, marking a significant victory in wildlife advocacy.

Over her career, Newman collaborated with leading organizations, including the Animal Welfare Institute, the International Fund for Animal Welfare, and the International Wildlife Coalition. Her ability to navigate complex legislative landscapes contributed to policies that protected seals, whales, and countless other species. Most recently, her campaign against the use of kangaroo skin in athletic shoes led major brands to discontinue its use, a testament to her enduring impact on the welfare of wild animals.

Read more: Legacy.com obituary 

Orrin H. Pilkey, 90 (U.S.)

Orrin H. Pilkey was a towering figure in the fight to protect America’s fragile coastlines, known for his blunt advocacy against coastal development and engineering solutions like sea walls and beach nourishment. A geologist by training and a communicator at heart, Pilkey’s message was simple but powerful: “Beaches are dynamic landscapes that thrive when left alone.” He famously quipped, “Where there are no buildings, there is no erosion problem.”

His influence extended far beyond academia. Pilkey’s work at Duke University and his founding of the Program for the Study of Developed Shorelines provided the scientific grounding for legislative victories like North Carolina’s bans on sea walls and restrictions on coastal development. He also spearheaded the controversial but ultimately successful effort to relocate the Cape Hatteras Lighthouse, demonstrating the feasibility of retreat in the face of rising seas.

While his critiques of development earned him accolades from environmentalists, they also drew ire from developers and politicians. Pilkey’s outspoken style blurred the line between science and advocacy, but his legacy—a coastline more attuned to natural processes—is undeniable. His books, including The Beaches Are Moving and Useless Arithmetic, remain essential reading for those grappling with the realities of sea-level rise and climate change.

Read more: New York Times

Bob Sallinger, 57 (U.S.)

Bob Sallinger, a tireless champion for wildlife conservation and urban greenspaces, died on October 30th, at the age of 57. His decades of advocacy reshaped environmental protections across Oregon.

For over 30 years, Sallinger served as the conservation director of the Bird Alliance of Oregon, where his efforts helped safeguard key species and habitats. His work with peregrine falcons, including securing protections for their nesting sites on Portland’s bridges, transformed the Fremont Bridge into one of Oregon’s most productive falcon habitats.

Sallinger’s expertise extended beyond urban conservation. As an architect of the Elliott State Research Forest, he fostered collaboration among diverse stakeholders to ensure Oregon’s first research forest balanced public access, ecological preservation, and scientific study. His recent tenure as executive director of Willamette Riverkeeper saw him champion legislative initiatives, including the Beaver Bill, which reclassified beavers as a protected species.

Widely respected for his dedication, Sallinger was described in media reports as “the face of conservation in Portland.”

Read more: Oregon Public Broadcasting | Oregon Live

Sumit Sen, 69 (India)

Sumit Sen was a pioneering ornithologist and digital archivist. A former director at American Express Bank, Sen’s passion for birdwatching and photography transformed him into a leading figure in documenting and preserving the avian life of Bengal and beyond.

In 1999, driven by his daughter’s inquiry about bird information that he found lacking, Sen founded kolkatabirds.com, an early digital archive. This platform became an important resource for bird enthusiasts and researchers, featuring meticulously collected and scanned photographs, and was at one point the only such repository in India. His work not only spotlighted Bengal’s bird species but also influenced ornithological studies nationwide.

Sen’s contributions extended to conservation. He funded crucial studies, such as research on endangered vultures, and mentored a generation of ornithologists. Colleagues remember him as a staunch advocate for ethical birdwatching, opposing practices like using bird calls to attract subjects for photography.

Beyond birds, Sen expanded his archival efforts to include fish species from the Sundarbans, leaving a broader legacy of natural history documentation. A beloved mentor and tireless conservationist, Sumit Sen’s work remains an invaluable resource and inspiration for future generations.

Read more: Times of India

Carlos Andrés Ascué Tumbo (Colombia)

Carlos Andrés Ascué Tumbo, known to friends and comrades as “Lobo,” or “Wolf,” was no stranger to the forces that threatened his land and his people.

The son of Colombia’s Andes mountains, he belonged to a long line of Indigenous Nasa defenders and was a dedicated educational coordinator and leader.

But in a country labeled as the world’s deadliest for environmental defenders, his commitment came at a steep cost. On August 29th, while picking up his daughter from swimming lessons in the village of Pescador, Carlos became the 115th social leader killed in Colombia this year.

For Lobo, leadership was not just about grand gestures but a lifelong devotion to his community. From childhood, he trained with the Indigenous Guard, the Kiwe Thegnas, the unarmed force responsible for defending Indigenous lands in Cauca from illegal armed groups.

He grew up learning that the land was more than a resource; it was a living entity, a spirit to be cherished and protected. His comrades remembered how he would patrol the hills in the dead of night, carrying only a ceremonial baton marked by green and white strings. This symbol of identity and resilience was all the Indigenous Guard carried against heavily armed drug traffickers encroaching on their ancestral territories.

Read more: The underreported killing of Colombia’s Indigenous land guardian, ‘The Wolf’

Nancy Wallace, 93 (U.S.)

Nancy Wallace, whose relentless efforts turned the Bronx River from an industrial dumping ground into a vibrant greenway, passed away on February 15th. She was 93.

A career educator and civic leader, Wallace joined the Bronx River Restoration board in 1982, initially as a temporary volunteer. Instead, she became the driving force behind its transformation, serving as executive director for 22 years. At the time, the Bronx River—a rare freshwater course in New York City—was a forgotten wasteland of rusting cars and discarded appliances. Under her leadership, it became a haven for wildlife and a recreational corridor for New Yorkers.

Wallace mobilized diverse coalitions, from suburban Westchester towns to underserved Bronx communities, raising funds and securing political support to reclaim the riverbanks. She persuaded local businesses to donate supplies, galvanized volunteer groups like Boy Scout troops, and orchestrated cleanups and riverbank restoration projects. Her efforts helped establish urban oases like Starlight Park and laid the groundwork for the Bronx River Greenway.

Read more: New York Times

George Woodwell, 95 (U.S.)

George Woodwell, a visionary ecologist who founded the Woods Hole Research Center and shaped global understanding of climate change, died on June 18th. He was 95.

Woodwell’s scientific legacy is immense. His early research on DDT revealed its persistence in ecosystems and accumulation in food chains, providing critical evidence for the U.S. ban on the pesticide in 1972. He was also instrumental in founding the Environmental Defense Fund, a groundbreaking organization combining scientific and legal expertise to advocate for environmental protection.

Climate change became his central focus. As early as 1972, he convened the first international conference on what he termed “the carbon dioxide problem.” His testimony before Congress in 1986 highlighted permafrost thaw and deforestation as urgent climate threats—issues that remain at the forefront of research.

Beyond research, Woodwell played key roles in founding the Natural Resources Defense Council and World Resources Institute and contributed to the creation of the Intergovernmental Panel on Climate Change. His work blended scientific inquiry with activism, a hallmark of his career.

Read more: Woodwell Climate | New York Times

If there are people you feel should be included in this list, let Mongabay know.

Updates:

• 12/29/24 (7:30 pm Pacific): Added Jimmy Carter.