Politics and society largely dictate the ambitions of climate policy and therefore the trajectory of greenhouse gas emissions, but models and projections of climate change rarely include political and social drivers. A study from the University of California, Davis simulated 100,000 possible future policy and emissions trajectories to identify relevant variables within the climate-social system that could impact climate change this century.
The study, published today in the journal Natureindicates that public perceptions of climate change, the future cost and effectiveness of climate mitigation and technologies, and how political institutions respond to public pressure are all important determinants of the extent to which the climate will change during the 21st century.
“Small changes in certain variables, such as the responsiveness of the political system or the level of public support for climate policy, can sometimes trigger a cascade of feedbacks that trigger a tipping point and dramatically alter the trajectory of emissions over the century” , said the leader. author Frances C. Moore, assistant professor in the Department of Environmental Science and Policy at UC Davis. “We are trying to understand what it is about these fundamental socio-political-technical systems that determine emissions.”
Coupling climate and politics
The authors note that the greatest uncertainty in understanding long-term climate impacts is what emissions will be in the future. Most climate and energy modeling treats politics as something outside the models. But to prepare for climate impacts, adaptation planners need to understand the likelihood of different temperature outcomes for decades to come.
For this study, the authors modeled 100,000 possible future pathways for climate policy and greenhouse gas emissions. They used an integrated, multidisciplinary model that connected data across a wide range of social, political, and technical domains. These scenarios included public and political support, social perceptions of climate change, how quickly collective action or carbon pricing responds to changes in public opinion, and other inputs.
The trajectories fell into five groups, with warming in 2100 varying between 1.8 and 3.6 degrees Celsius above the 1880-1910 average, but with a high probability of warming between 2 and 3 degrees Celsius at the end of the century.
The results indicate that the perceptions of people and social groups, improvements in mitigation technologies over time, and the responsiveness of political institutions are the main drivers of future emissions, even more so than individual actions.
The study is not prescriptive. Rather, it examines the socio-political and technical system that determines future emissions, integrates this information into existing climate models, and relates it to individual, community, national, and global scales.
“Understanding how societies respond to environmental change and how policies flow from social and political systems is a key issue in sustainability science,” Moore said. “I see it pushing this research and also being useful for climate adaptation and impact planning.”
The study’s co-authors are Katherine Lacasse of Rhode Island College, Katharine Mach of the University of Miami, Yoon Ah Shin of Arizona State University, Louis Gross of the University of Tennessee, and Brian Beckage of the University from Vermont.
The study was supported by the National Socio-Environmental Synthesis Center with funding from the National Science Foundation.
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Material provided by University of California – Davis. Original written by Kat Kerlin. Note: Content may be edited for style and length.