He also became the first director of the United Nations Convention on Biological Diversity and the founder of the African Center for Technology Studies in Nairobi, Kenya, a pioneering group that married government policy with science and technology to spur sustainable development and foster distinctly African perspectives on science.
Professor Juma died on Dec. 15 at his home in Cambridge, Mass. He was 64. His wife said the cause was cancer. At his death he was widely credited as having been an important force in ensuring that biotechnology would play a critical role in improving economic life in many developing countries, especially in sub-Saharan Africa.
“Calestous understood that people often resist the changes that come with innovation, and that overcoming this resistance can be very important in enabling societies to move ahead,” said Douglas W. Elmendorf, dean of the Kennedy School. “So he tried to understand why people resist innovation, and what can be done to make them feel comfortable with change.”
Professor Juma’s latest book, “Innovation and Its Enemies” (2016), described how technological change is often greeted with public skepticism. Beneath such opposition, he argued, is the belief that only a small segment of society will benefit from potential progress, while the much broader society bears the greatest risk.
Successful policymaking must take into account people’s feelings, he believed. When Professor Juma helped design a stove for use in developing countries, its metallic cylinder was replaced with a clay lining to improve efficiency. But the prototype caused less smoke — attracting more mosquitoes — and villagers worried that metal workers could lose their jobs. A later model used metal and clay.
“Ultimately, all development is experimental; no one knows what they are doing,” Professor Juma said with a laugh in 2014. “Africans need the chance to experiment as well. They will make mistakes, but they can learn from them, too.”
Professor Juma could be lighthearted in the classroom or in public in order to make his points. With more than 100,000 followers on Twitter, he shared with them cartoons that teased skeptics of science and innovation. One of his last posts featured a game show called “Facts Don’t Matter.” In it, a contestant is told: “I’m sorry, Jeannie, your answer was correct, but Kevin shouted his incorrect answer over yours, so he gets the points.”
“Calestous was very serious about getting his work right, but he was not serious about himself,” Mr. Elmendorf said. “He shared his enjoyment of the research and teaching, though he was working on life-or-death issues for many people. He was incredibly optimistic.”
Professor Juma was born to John Kwada Juma and Clementina Nabwire Juma in the village of Busia, in western Kenya, on June 9, 1953. He grew up nearby in Port Victoria.
“Port Victoria was as remote as it gets — a small fishing village on Lake Victoria at Kenya’s westernmost point,” said Ken Kobe, who taught Professor Juma while serving as a Peace Corps volunteer there in 1969-70.
After graduating from Egoji Teachers’ Training College in central Kenya in 1974, Professor Juma became a science teacher in Mombasa, a port city on the Indian Ocean. He went on to write so many letters to the editor of the Nairobi-based newspaper The Daily Nation that it hired him in 1978 to be its first full-time science and environment correspondent.
Wangari Maathai, the environmentalist who became the first African woman to win a Nobel Peace Prize, hired Professor Juma to work at a nonprofit in Nairobi. Encouraged by Ms. Maathai, he won a scholarship and earned a doctorate in science and technology policy studies in 1987 from the University of Sussex in England.
He met his wife, who also works in sustainable development, at a conference in Montreal. They married in 1987 and moved to Kenya.
Professor Juma experienced two major ecological disruptions in his childhood, Ms. Field-Juma said. One was the introduction of Nile perch to Lake Victoria to help the fishing industry. Though it did benefit the area economically for a time, it also contributed to the depletion, to near-extinction, of stocks of many other types of fish in the lake.
The second change was the British colonial government’s deforestation of much of the Port Victoria region, which dried out what had been a wet and fertile area. “The microclimate of that region was irreversibly changed,” Ms. Field-Juma said.
On his return to Kenya with his wife, he sought a scientific solution to the agricultural crisis.
“I started to run into all the people who had collected seeds of fruits and vegetables, mostly fruits, that had disappeared,” he said in an interview in 2003. “And some of them explained to me that those fruits have disappeared because the area had dried up. And they would pose this question to me: ‘You scientists, are you able to grow these fruits in places where there is less water?’ ”
Professor Juma recognized the potential of genetic modification to address such issues and to help solve Africa’s broader agricultural problems, distilling his thinking in the 1989 book “The Gene Hunters.”
The book helped pave the way for the Convention on Biological Diversity, a United Nations treaty signed by more than 150 governments in 1992 to protect the survival of diverse species and ecosystems.
Besides his wife, he is survived by his son, Eric, and his sister, Roselyda Nanjala.
Until he was hospitalized, Professor Juma had planned to host about 20 international students for Thanksgiving in Cambridge. Instead, he joined them from the hospital by Skype, sharing stories and discussing development with them.
“It was just what he wanted,” Ms. Field-Juma said, “and he wasn’t even there.”