Born in Ireland and raised in Northern Ireland originally, he was educated at
Queen's University Belfast, receiving a B.Sc. in applied mathematics in 1960, and completing his Ph.D. in applied mathematics in 1962. McElroy worked in atmospheric science at
Harvard, and led atmospheric science and policy work. He headed Harvard University's Center for the Environment and chaired the Interfaculty Initiative on the Environment. In 1984 he won the
George Ledlie prize for his work on planetary atmospheres. He served as Founding Chair of Harvard's Department of Earth and Planetary Sciences and has focused his research especially on effects of human activities on the
global environment. He recorded two audible books,
The Modern Scholar: Global Warming, Global Threat (2004) and
Fueling the Planet: The Past, Present, and Future of Energy (2009). McElroy died on January 8, 2026, at the age of 86. ==Selected publications==