Members of the public find the risks of climate engineering technology more likely than any of the benefits, according to an article published in the current edition of the Proceedings of the National Academy of Sciences. Authored by scholars from the NSF Center for Nanotechnology in Society at the University of California, Santa Barbara (CNS-UCSB) and the University of British Columbia, the article, titled "Using Decision Pathway Surveys to Inform Climate Engineering Policy Choices," describes a new method for understanding public concerns regarding the ethics and governance of new technologies, and sheds light on public sentiment towards technologies that either capture greenhouse gases or reflect sunlight away from Earth's surface.

Such research is crucial because even if the goal of reducing global temperatures by two degrees Celsius -- as set forth in the Paris Agreement signed onto by 195 nations in December -- is achieved, it will not halt the impacts of global climate change, including sea-level rise, shifts in rainfall, and extreme weather events . Given this context, a growing number of scientists are advocating for climate engineering technologies, also referred to as "geoengineering." In choosing whether and in what manner to implement such technologies, policymakers must inform the public about their benefits and risks while also listening to public input on policy options.

The two most typical methods of gauging public opinion are surveys and deliberative focus groups. The former allows for greater sample sizes while the latter allows for dialogue and learning. The topic of climate engineering poses challenges to both of these methods, however, because such technology is not well-understood by the public and its outcomes are uncertain.

Understanding public perceptions of emerging technologies is one of the central research objectives at CNS-UCSB. In order to assess public views of climate engineering, researchers affiliated with CNS-UCSB have devised a tool called a "decision pathway survey." In combining the strengths of both surveys and deliberations, these decision pathway surveys include learning through tutorials, providing explanation of how the values and ethics of respondents inform their decision-making process in general and as they learn more about climate change and climate engineering technology.

CNS-UCSB Director Barbara Herr Harthorn explains, "The pathway approach provides a more conversation-like form of survey that can tell us more about why public views develop rather than just the end judgments at which the public arrives."

The two climate engineering approaches introduced in the study are sunlight reflection technologies (SRTs) and carbon dioxide removal technologies (CDRTs). Notable results of the surveys were as follows: