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​​​RIC Assistant Professor of Psychology Katherine Lacasse stands next to an electric vehicle charging station on the RIC campus.

Katherine Lacasse, assistant professor of psychology at Rhode Island College, is among the co-authors of a new study that concludes human behavior can have a major impact on climate change. Lacasse said the study, published in the journal Nature Climate Change, Vol. 8, is rare because prior climate change studies don’t tend to include how the public’s responses to climate change may impact global temperature change. 

“Most climate models have been created by individuals who focused more on natural systems and perhaps economic processes, but not on human risk perception and behavior. And that’s the new piece we’ve added,’’ Lacasse said, noting that the study took four years to complete and more than 700,000 simulations to obtain results. 

Lacasse was among a dozen professors from a variety of disciplines, including biology, geography, mathematics and psychology, to work on the study, which was a combined effort of the Working Group on Human Risk Perception and Climate Change at the National Institute for Mathematical and Biological Synthesis (NIMBioS) at the University of Tennessee, Knoxville and the National Socio-Environmental Synthesis Center (SESYNC) at the University of Maryland. Both institutes are supported by the National Science Foundation. Other authors of the study included faculty and scientists from the University of Vermont, Dartmouth College, the State University of New York at Buffalo, Arizona State University, Utah State University, Oak Ridge National Laboratory and Climate Interactive.

“When we started the study we asked whether human responses to climate change would even matter at all,’’ she said. “However, our findings show it is important because our model predicts a range of temperature increases by the year 2100, from 3.4 to 6.2 degrees Celsius. If humans respond to the increasing number of extreme weather events and change their behavior to reduce their emissions, we will more likely see temperature changes on the lower end of that range.’’

The study found that long-term, less easily reversed behavioral changes, such as insulating homes, installing solar panels or purchasing hybrid cars, had a greater impact on mitigating greenhouse gas emissions, which reduce climate change. Changes that require repeated performance, such as manually adjusting thermostats in homes or offices and trying to drive fewer miles, had less impact on greenhouse gas emissions, the study showed.

“People are likely to make behavior changes if they perceive it’s easy to do, inexpensive and accessible,’’ Lacasse said. “Programs or policies that help reduce the cost and difficulty of making long-term changes can help support people to take big steps that have a meaningful impact on the climate. For example, many community solar programs are emphasizing that those who have solar panels meet with neighbors who don’t to answer questions about pricing and financing options, and learn the best ways to install them.’’

Lacasse, who has taught social psychology and research methods courses at RIC since 2015, said much of her previous work looks at what motivates people to be environmentally friendly. A 2007 Providence College graduate, Lacasse earned her master’s and doctoral degrees in social psychology from Clark University in Worcester, Massachusetts. 

“Climate change is one of the biggest global issues that faces our society,’’ she said. “I was really motivated to study it because I believe psychologists have a lot to say about why people act the way they do and how we can solve climate change issues.’’

Lacasse said she plans to share aspects of the climate change study with students in her RIC courses in the spring semester.

“Each semester my students come up with research questions and ways to test those questions to determine real world impact,’’ she said. “I think my study will be a useful example for students.’’

She said she’s encouraged by the positive feedback the study has received from climate researchers.

“It’s a little too early to know the impact,’’ she said. “But our goal was for this to play a role in future climate models and research. We have plans to expand our model by by looking at how the behavior of one population may have an impact on another population, and see if that will yield different results.’’

For more information on the climate change study, contact Lacasse via email at