In a paper published earlier this month, Ohio State professor Skyler Cranmer and his colleagues conducted first of its kind research on international treaties. Credit: Courtesy of Skyler Cranmer

Peer pressure isn’t just for high schoolers. It plays out on larger scales too. In fact, it plays out on the largest stage out there: international diplomacy.

By using a complex data set of different countries, Ohio State associate professor Skyler Cranmer, Ph.D. candidate Benjamin Campbell and their colleagues have discovered how nations influence others to ratify environmental treaties.

Their research consisted of looking at different treaties throughout history and seeing the effect a country like the United States would have on overall ratification. This was done by looking at how long it took other countries to sign — or not sign — after a powerful country had made its decision.

The research began in mid-2014 when Cranmer and his colleague Tobias Bohmelt, a professor at Essex University in England, submitted a grant proposal to the National Science Foundation.

They were then notified of funding in 2015 and then added Campbell as well as Frank Marrs, a Ph.D. candidate in statistics, and Bailey Fosdick, an assistant professor of statistics, both from Colorado State University

In the end, the research produced a model that could predict how other countries would react when an individual country ratified an international environmental agreement between 1972 and 2000.

In one example, the researchers looked at how the signing of the United Nations Framework Convention on Climate Change by the United States in 1992 might have had an influence on Russia to ratifying the treaty.

Cranmer said that the United States’ decision seemed to significantly impact the actions of not only Russia, but also other countries around the world.

“Many nations influence each other and part of what we have developed is a general tool for understanding who and by how much,” Cranmer said. “In the paper, we focus on the UNFCCC and how the U.S. seems to influence Russia, France and Mexico quite a bit.”

Campbell said the research doesn’t just reflect and model past treaties though. He said it also has implications for today’s treaties and their conclusions are reflected in current events.

“In regards to when President Trump pulled the United State out of the Paris Climate Agreement in 2017, this affects more than just the United States,” Campbell said. “Our research should indicate that should have profound implications, not just in how other countries ratify that one treaty, but how they they ratify other treaties.”

The paper was finished up in late 2018 and published March 2019 in the PLOS ONE, a nonprofit open-access science, technology and medicine publisher.