Social justice advocate and early wind farm programmer Larry Rosenberg, 73, of Cambridge, died on May 2. Passionate about international development, he worked in both his professional and personal life to make the world a better place.

Raised in Pittsburgh, Lawrence Eric Rosenberg was the first child of Irwin and Mildred Rosenberg, and brother to Ilene. He loved math so much he would sleep with his slide rule under his pillow. Nonetheless, he once agreed to miss a day of school to attend the historic seventh game of the 1960 World Series.

Larry set out to study at Princeton but found it too constricting amidst the burgeoning anti-war, feminist, and civil rights movements that were capturing his attention. After two years, he transferred to the University of Michigan, where he became active in Students for a Democratic Society. He received a B.A. in psychology in 1970.

He later moved to Somerville, where new friends were pursuing a countercultural lifestyle. He met Judy Somberg within days. They lived for years in a collective household, Oakbyte. Among other pursuits, Larry played violin in Swingshift, a political rock band, drawing on his childhood classical music training.

When Larry and Judy decided to have children, they initially planned not to marry, in solidarity with same-sex couples who were denied that right. However, months away from the birth of their first child, they acceded to parental pressure and married, on April Fools’ Day. They welcomed a daughter, Lucia, and three years later a son, Ben—and gave both their mother’s last name.

Larry’s early work included a stint as a hospital orderly—a position he took to start a labor-organizing campaign. He was once fired on the first day of a bus-driving job for refusing to carry strikebreakers across a picket line.

He held several technology-focused positions, spending half of the 1980s programing computers for the nation’s first major wind farm developer. He later directed staff at a research institute that worked in opposition to the proliferation of military weapons.

After earning a master’s degree at the Harvard Kennedy School, Larry began a new career in international development. His projects ranged from producing a UN-published book on municipal solid waste management in developing countries to supervising an international working group planning the incorporation of information technology in the Bolivian education system. He researched and managed projects at the Harvard School of Public Health for more than a decade.

Outside of work, Larry was active in many political causes, including advocating in the 1980s for a negotiated peace agreement in Central America. Larry and Judy took their young kids to Nicaragua in 1989 to support the country’s then-socialist government while immersing themselves in another culture. Larry spent that year teaching national education ministry employees how to use computers.

Later, Larry advocated for many years for a two-state solution to the Israeli-Palestinian conflict, focusing on outreach to the Jewish community in greater Boston. He subsequently turned his focus to climate change, championing clean energy bills in the state legislature and opposing new fossil fuel infrastructure. He wrote and published many letters to the editor in newspapers across the state.

When Larry was diagnosed with lymphoma in 2008, he and Judy stepped up their international travel. Larry wanted to understand what was really going on in a place. He’d learn some of the language, meet anyone’s distant contacts, and ask taxi drivers about the economy and their lives. In the summers, he backpacked with friends Ferd and Steve in California. Often, he could be spotted walking around Cambridge with a backpack filled with rocks, for training.

Larry visited his granddaughter, Simone, frequently—singing to her, telling her stories, and when she was six years old, helping her make a spreadsheet of everyone she knew. He took immense joy from being with his family and friends.

Larry was admired as an inquisitive conversation partner, and a sharp-eyed editor eager to help any friend with a resume or letter. He was a critical thinker remembered by many for engaging them in political discussion and challenging them to hone their arguments. He took a deep interest in everyone he met.

Shortly after the pandemic began, Larry’s lymphoma transformed into an aggressive type. When treatments no longer worked, he continued his commitment to science and the public good and arranged to donate his body to the UMass Medical School.

Larry is survived by his wife Judy; his daughter Lucia Somberg, her wife Connie Yip, and their daughter Simone Yip; son Ben Somberg and his partner Jess Luna; sister Ilene Price and her husband Jeff; and many cousins, nieces, and nephews.

In lieu of flowers, the family welcomes donations to climate-focused organizations such as 350.org. Larry’s presentation about the climate crisis that he honed in his final days is available at bit.ly/larry-climate.