Inside classrooms, clinics and Congress, Dr. Paul Epstein fervently defended the health of both humans and the environment. He understood the powerful connections between the two -- how losing more of the world's forests or ice sheets, for example, could translate into the loss of more human lives.
The public health expert now leaves that work to his students and the countless others he taught and inspired over many years. Dr. Epstein passed away from lymphoma at his Boston home on Sunday. He was 67.
"This is a terrible loss for all of humanity," James McCarthy, a professor of biological oceanography at Harvard University and long-time colleague and friend, tells The Huffington Post.
Dr. Epstein, a physician and associate director of the Center for Health and the Global Environment at Harvard Medical School, started his medical career working in low-income communities, from East Cambridge to the east coast of Africa. After spending 1978 through 1980 in Mozambique with his wife, Andy, a nurse, he enrolled in a master's program in tropical public health at Harvard. Soon he was making critical connections between the emergence and re-emergence of infectious diseases and climate change.
But it was while attending the United Nations Conference on Environment and Development in Rio de Janeiro in June of 1992 that Dr. Epstein's public health mission became solidified. There, he and Dr. Eric Chivian, a Harvard psychiatrist and now director of the Center they co-launched in 1996, noticed something alarming: While wolves, whales, oceans and trees garnered ample attention, "no one was talking about human beings," recalls Dr. Chivian.
The pair responded by holding a press conference in which Dr. Epstein linked the cholera epidemic then going on in Peru with environmental changes, including rising ocean temperatures and discharges of sewage that had become a nutrient soup in which cholera bacteria could grow. In an interview with HuffPost this July, Dr. Epstein said that, "in general, warmer sea surface temperatures and a warmer atmosphere lead to increasingly frequent and heavy rain." He added: "These intense rains can flush nutrients, organisms and chemicals into coastal marine habitat and trigger an algal bloom."
"We shared the belief that policy makers and increasingly the general public were acting as if they had a choice about whether they preserved and protected the natural world or not," Dr. Chivian said. "We both felt that was a very dangerous delusion. Humanity doesn't have a choice -- our lives depend on it."
Over the next several years, Drs. Epstein and Chivian continued to make the concept of global environmental change both concrete and personal for people, primarily by relating those changes to human health.
That meant connecting the dots between our health and our choices, including the continued reliance on fossil fuels as our primary energy source, notes Richard Clapp, professor emeritus at Boston University School of Public Health and another of Dr. Epstein's long-time colleagues and friends.
Dr. Epstein was one of the first people to recognize the less obvious health effects of greenhouse gases, from ragweed pollen to extreme weather events.
"His passion for addressing societal ills, and yet his patience for finding effective solutions to problems at the intersection of environmental change and human health, were endearing qualities that students in his classes came to respect and revere," says McCarthy.
A case in point can be found in the Boston Globe's guest book: "Paul became an instant mentor of mine the minute we met during my internship at Cambridge Hospital in 1991. His was the life I wanted to live, the career I wanted to emulate," wrote Timothy Holtz of Bangkok, Thailand. "He was the total package, primary care physician, scientist, author, social justice activist, and a great husband and father. Paul linked me up with his progressive medical contacts in South Africa in 1993, and I've never looked back."
For 15 years, Dr. Epstein and McCarthy co-taught an undergraduate course at Harvard. "Every year I looked forward to a two-hour lecture of his that stretched across a long blackboard," says McCarthy. "He methodically worked from the smallest organism to larger ones as he revealed his encyclopedic knowledge of pathogens and disease vectors whose abundance and/or virulence can be influenced by environmental conditions."
This was one of the many concepts that were imparted in Dr. Epstein's "Human Health and Global Environmental Change" course at Harvard Medical School, which has since been adapted by medical schools, colleges and high schools around the world. The Center is currently developing a similar program for middle schools.
"As Earth's climate changes, it will do far more than maroon polar bears amid melting ice," Dr. Epstein wrote in the introduction to his 2011 book "Changing Planet, Changing Health." He went on to link climate change with deadly heat waves and heavy rains, and explained how it is a driving force for the spread of malaria-carrying mosquitoes and shrinking supplies of clean water.
"Clearly," he wrote, "climate change is hazardous to our health."
The efforts to spread that message continue. "It's been frustrating, especially in recent years, when it seems like we're taking many steps back," says Dr. Chivian. "It's hard to believe that only one Republican candidate for president accepts the science when all the major scientific academies of the world, all major medical academies and major colleges have issued warnings about where we're headed in altering the global environment."
"That's why it so important to identify the medical consequences of these changes," he adds. "And that's what Paul did so effectively."
Full disclosure: This reporter attended Dr. Epstein's class at Harvard Medical School in 2004.