The United States was the world’s largest source of carbon emissions for more than a century. In a new analysis, researchers document the changing trends in U.S. carbon emissions from the late 19th century to the early 21st century, focusing on emissions from fossil fuels and industry. They discuss the main factors that contributed to the rollercoaster of changes in historical carbon emissions. The authors close by offering lessons from the U.S. experience for developing countries.
The analysis, written by researchers at Carnegie Mellon University, the University of Montreal, and Boston College, will appear in the Journal of Economic Perspectives .
“The growth rate of U.S. carbon emissions and carbon emissions per capita shows striking variation over time,” explains Karen Clay, professor of economics and public policy at Carnegie Mellon’s Heinz College, who coauthored the analysis. “Yet our understanding of this historical variation in carbon emissions is surprisingly limited.”
The authors divide their analysis into four periods—the years before 1920, 1920 to 1960, 1960 to 2005, and the years after 2005—and discuss the main drivers of national carbon emissions, as well as trends in carbon emissions in the electricity sector. They conclude with a discussion of implications for decarbonization efforts, particularly in developing economies where energy demand is rising rapidly.
While each country faces unique institutional, political, and technological constraints, historical patterns offer useful guidance on avoiding carbon-intensive development paths and navigating the complex tradeoffs between local and global environmental objectives. Among the implications:
“Looking to the future, effective climate and energy policy must draw on historical experience to design frameworks that minimize unintended consequences,” suggests Akshaya Jha, associate professor of economics and public policy at Carnegie Mellon’s Heinz College, who coauthored the analysis. “Developing countries can avoid some of the pitfalls encountered by the United States by investing in efficient technologies, avoiding overreliance on coal, responding strategically to geopolitical shocks, and crafting environmental regulations that reflect both local and global pollution objectives.
“By fostering innovation, maintaining regulatory flexibility, and holistically accounting for environmental externalities, policymakers can meet their climate goals more effectively while ensuring access to energy and fostering economic growth.”
The analysis was funded by the Wilton E. Scott Institute for Energy Innovation at Carnegie Mellon University.
Journal of Economic Perspectives
Carbon Rollercoaster: A Historical Analysis of Decarbonization in the United States
14-Jul-2025