GROWING UP in Connecticut and New Jersey, Harvey Brooks Professor of International Science Bill Clark was the classic outdoorsy kid, wading in streams, looking under rocks, and catching critters, preferably snakes. As a Yale college student in the late 1960s—pulled between ecology and political science—he worked on environmental policy in New York City under Mayor John Lindsay and in Washington, D.C., for the federal government of Richard Nixon. In grad school in the 1970s, Clark studied resource management, shinnying up balsam fir trees and using computer modeling to understand how rare but catastrophic insect outbreaks periodically destroyed boreal forests and forest-based jobs in eastern Canada and the United States.

Those early experiences led to Clark’s lifelong interest in applying scientific knowledge to public problems, particularly the need to promote responsible stewardship of planet Earth through sustainable development. As a young scientist, he ran one of the first government reviews of greenhouse gas emissions and climate change, won a 1983 MacArthur Foundation “genius” grant, and directed an ambitious new program, “Sustainable Development of the Biosphere,” at an international think tank in Austria.

man standing at a sustainability presentation

Clark was ahead of his time, a pioneer in a field in which he has had a profound impact throughout his 45-year career, which includes more than three decades at the Kennedy School. Today “sustainability” is a ubiquitous idea, with ambitious sustainable-development goals being set by businesses, universities, nonprofits, and governments around the world.

“There’s been a transformative revolution at all levels, from individuals to global organizations,” says Clark, as people “take notice of how our present actions can damage our neighbors today and our children in the future.” Increasingly, people “accept responsibility to act on that knowledge,” he adds. “A new norm is emerging for sustainable development.” 

“Bill helped create the foundation of the house that the field of sustainability is built upon. He’s made enormous contributions,” says HKS colleague Henry Lee, Jassim M. Jaidah Family Director of the Belfer Center’s Environment and Natural Resources Program. Longtime HKS Professor John Holdren, a former science advisor to President Barack Obama, says, “Bill Clark has a deeper understanding of the science of sustainability and the intersection with public policy than anyone else I know.” Stanford University Professor and former Dean Pamela Matson, who started working with Clark in the late 1990s on a National Academy of Sciences Board on Sustainable Development, says, “Bill has the ability to bring everyone to the table, harnessing their ideas and knowledge in ways that advance science and problem-solving.” Clark cochaired a major National Academy study, “Our Common Journey: A Transition toward Sustainability,” that helped launch sustainability science in the United States and around the world.

Matson, Clark, and Krister Andersson coauthored an influential 2016 book, Pursuing Sustainability: A Guide to the Science and Practice, that synthesized the big ideas in the field today. It explored sustainable development as an effort to meet “the needs of the present without compromising the ability of future generations to meet their own needs,” a formulation of sustainability goals first advanced in 1987 by the World Commission on Environment and Development. With his coauthors of the 2016 book, Clark echoed that commission’s call for global action, urging “informed agitation” to meet sustainable development challenges ahead. “Our ability to prosper now and in the future,” they wrote, “requires increased attention not just to economic and social progress but also to conserving Earth’s life support systems: the fundamental environmental processes and natural resources on which our hopes for prosperity depend.” 

man standing with bicycle

We have to get through this shock in ways that help people today while rebuilding in ways that will help people tomorrow to cope better with the shocks that the future inevitably holds for them.

Bill Clark

The book, together with an ongoing online update of the field edited by Clark and Alicia Harley PhD 2018, summarize an emerging framework for pursuing sustainability grounded in a broad set of resources or capital assets. These include not only natural capital (land, ecosystems, climate) but also human capital (population size and distribution, education and health), manufactured capital (buildings and infrastructure), social capital (culture, norms, rules), and knowledge capital. Together, these assets constitute the foundations on which well-being can be built—but only by those with access to them. For sustainability, the capacity of these assets to support development must be conserved into the future and access to them must be more equitably distributed. Many of these foundational assets, however, are now being threatened by human activities that degrade not only our climate and ecosystems but also our trust in knowledge and institutions.  And access to them is becoming more rather than less inequitable. 

“The damages to our asset base are serious and getting worse,” says Clark, “exacerbated through multiple acts of vandalism by the Trump administration. I have to believe that the Biden-Harris administration is going to pay more attention to science, justice, and the common good.  I’m hopeful for better days ahead. The long-term quest for sustainable development has obviously been severely damaged by the COVID-19 pandemic, as it has by earlier pandemics, economic collapses, and wars. We have to get through this shock in ways that help people today while rebuilding in ways that will help people tomorrow to cope better with the shocks that the future inevitably holds for them.” 

Clark is encouraged that global progress is underway as an increasing number of organizations—from communities to corporations to countries—draw up and implement sustainability plans, measure how well they are doing in achieving their goals, and provide more transparency about their efforts. Stakeholders in the activities of these organizations are demanding more accountability on the sustainability front. Local governments set targets for everything from building efficiency to public transit. Universities develop plans for greener buildings, a reduced carbon footprint, and more-equitable access to their teaching and research. 

Since coming to the Kennedy School, in 1987, Clark has kept sustainability at the forefront of his work. He was the founding director of Harvard’s Sustainability Science Program, which has cultivated a generation of scholars and practitioners, training more than 140 fellows since its start, in 2006. He has continued his own research through a “Sustainability Science” project that has sought to promote research and technological innovations that can inform practice in areas such as agriculture, health, and energy. Clark has also long been a leader in Harvard’s University-wide climate and sustainability efforts as well as those at HKS. 

outside a building and some solar panels
Clark’s academic accomplishments have come hand in hand with his practical work in making Harvard University a more sustainable institution.

“Bill Clark has been a very important leader of the University and Kennedy School efforts to become more sustainable,” says HKS Dean Doug Elmendorf. “He understands that big institutions generally have a lot of inertia, and moving them requires consistent persistence, which Bill has shown. Bill also understands that universities depend on evidence in making choices. He has worked tirelessly to collect and use evidence about what’s happening in the world and what actions the Kennedy School and the University can take for the world.” Heather Henriksen MC/MPA 2008, who has led the University’s Office for Sustainability since 2008, says, “Harvard would not be where we are on sustainability today without Bill Clark. He has been such a pioneer and visionary.”

Clark cochaired the first two University-wide greenhouse gas emission task forces under President Emeritus Drew Gilpin Faust. Harvard adopted the 2008 task force recommendation to reduce the University’s carbon footprint by 30 percent by 2016 (from a 2006 baseline)—an ambitious target that was met on time, says Henriksen, who first met Clark when she was a Kennedy School student. That was achieved by changing energy supply and demand, including building efficiency, cleaner on- and off-site energy sources, and more renewable energy. Harvard’s latest Climate Action Plan seeks to make the University fossil fuel–neutral by 2026 and fossil fuel–free by 2050: aggressive targets based on recommendations from the 2016–2017 Climate Change Task Force.

Clark was also a faculty cochair of a committee that created the 2015 Harvard University Sustainability Plan, which addressed energy use, water use, waste, and landscaping. Annual reports and an online sustainability data hub provide transparent updates on how well Harvard is doing. Clark is currently co-chairing for President Lawrence Bacow a committee to formulate a second-generation sustainability plan for 2021–2030. It will expand the first plan to include issues such as healthy buildings, food services, air travel, investments, and overall well-being of the greater Harvard community. “We are on track to complete our initial report by the end of this academic year,” he says. 

Clark has taken on numerous leadership roles at the Kennedy School, including cochairing the HKS Sustainability Leadership Council. Elmendorf notes that sustainability efforts already underway at HKS have included installing solar panels on the roofs, reducing food waste and the use of plastic in food services, and shrinking the School’s carbon footprint. “We still have a tremendous amount to do,” he says. “We can do this work. Bill has taught me how to think about these problems in ways I had not thought of before.” 

Clark has also served as the longtime faculty area chair of the Kennedy School’s International and Global Affairs (IGA) program. Most recently, at Elmendorf’s request, he has co-led an effort to evaluate HKS course offerings and activities in the broad climate domain, an area of key concern to students. 

“Bill has an extraordinary degree of determination to get the job done,” says Holdren, Teresa and John Heinz Professor of Environmental Policy at HKS. “He’s an iron fist in a velvet glove who works well with others in a very collegial way. He’s a pillar of commitment and performance.” Amanda Sardonis, the associate director of the School’s Environment and Natural Resources Program, says, “Bill has very strong views and can be provocative. But he also recognizes that real progress is made through collaboration, good will, and determination. And when goals are met, he’s quick to give praise, share credit, and encourage celebration.”

There’s been a transformative revolution at all levels, from individuals to global organizations, [as people] take notice of how our present actions can damage our neighbors today and our children in the future.

Bill Clark

Teaching has also been a key priority for Clark, who is particularly proud of teaching awards he has received at both HKS and the College. One of his students was Alicia Harley, who met Clark in 2005 during her freshman year at Harvard, took his environmental policy course, and later earned a PhD in public policy under him.

“He’s an incredibly driven intellect who moves fast to connect ideas,” says Harley, who coteaches Clark’s undergraduate sustainability course and coauthored with him a recent review of sustainability science. “He expects rigor from his students, but he’s incredibly compassionate.” Beyond Harvard, “he’s a star in the field of sustainability science,” she says. 

As a world-recognized expert on sustainability science and its applications, Clark has long juggled his professional responsibilities at Harvard with diverse global sustainability projects in agriculture, public health, natural resource management, ecosystem services, and climate change. His lengthy list of accolades includes election to the prestigious National Academy of Sciences in 2002 as a “premier analyst” of “environmental science and policy.” 

Clark’s life personifies the adage “Think globally, act locally.” He puts into practice what he preaches. He has long biked to campus or taken public transportation from his home in Watertown. Harley recalls a time when Clark arrived to teach his sustainability course with a bloody leg from a bike accident, which he ignored until class was over. He and his wife, Anni, who is retired from a career in finance, own one car, a hybrid plug-in Prius. “She is my conscience and a practical genius in finding ways to conduct our daily lives that walk the talk of my professional life,” says Clark.

His self-admitted “sin” is occasional air travel to southern Austria, where he summers with his family in Kniezenberg—a town in the scenic Steiermark region where his wife grew up—and hikes, listens to classical music, and enjoys good food and wine. The couple, who met in the early 1970s at the International Institute for Applied Systems Analysis outside Vienna, have been married for 40 years and have two sons, Adam and Graham. 

At the end of this academic year, Clark will start a new chapter. He’ll retire from his longtime HKS duties in teaching and administration and move to research professor status, with far more time to pursue lifelong sustainability interests and be with family. “He told me he wanted to retire when he was still young enough to scamper up and down mountains,” says Elmendorf. “I’m going to miss Bill terribly. But he will remain a part of our community.” 

Clark says he also wants to make way for more-junior faculty members: “I personally accepted a moral obligation to get out of the way and give others the opportunities I had.” But he will continue to fight the good fight on the sustainability front. “Bill’s very passionate about the injustices and inequities in the world,” says Harley. “But fundamentally, he’s an optimist. You can’t devote yourself to the science of how to get the world to a better, more sustainable place without believing it’s possible.”

Cristine Russell, a longtime science journalist, is a senior fellow at the Kennedy School’s Environment and Natural Resources Program, Belfer Center for Science and International Affairs

Follow her on Twitter @russellcris.

Banner and inline portraits by Raychel Casey; Bill Clark/Harvard Sustainability photo by Kris Snibbe/Harvard University

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