BRACE | Benefits of Reduced Anthropogenic Climate changE
The Benefits of Reduced Anthropogenic Climate changE (BRACE) project is the first study undertaken by NCAR's Climate and Human Systems Project. BRACE explores impacts of climate change that could be avoided in a scenario where climate change is driven by lower emissions and radiative forcing (the Representative Concentration Pathway 4.5 scenario (RCP 4.5) versus a scenario where climate change is driven by a higher emissions and radiative forcing scenario (the RCP 8.5 scenario). The results of this study are being summarized in a special issue of Climatic Change, currently in progress. Data output and model projections are also available for some papers.
A recent assessment report from the Intergovernmental Panel on Climate Change (IPCC) shows that the RCP 8.5 scenario would likely lead to ~2.6-4.8 °C of warming, relative to recent temperatures, while the RCP 4.5 scenario would likely limit warming to 1.1-2.6 °C. The benefits of the reduction in climate change in RCP 4.5 would be the impacts avoided, as well as a potential reduction in the costs of adaptation. Understanding and quantifying avoided impacts is critical in order to weigh these potential benefits against the mitigation and geoengineering costs that would be incurred to reduce climate change from the higher to the lower climate change pathway.
The BRACE project involves 23 individual analyses and more than 50 authors from NCAR and from 18 partner institutions. Analyses address differences in physical climate outcomes between RCPs 4.5 and 8.5, statistical methods for measuring such differences, and consequent differences in societal impacts. The study draws on Coupled Model Intercomparison Project Phase 5 (CMIP5) simulations, a “medium ensemble” produced using NCAR's Community Earth System Model (CESM) for RCP 4.5, and a large ensemble of RCP 8.5 simulations from the CESM1 (CAM5) Large Ensemble Community Project.
Climatic Change Special Issue
A special issue of Climatic Change is currently in progress and features papers on BRACE results. Learn more about the special issue, and read published papers from the issue.
Efforts are underway for a BRACE 1.5 project, which extends BRACE work to look at outcomes under global mean temperature increases of 1.5°C and 2°C, respectively. Studies as part of this effort include global crop yield impacts, economic and biophysical impacts on agriculture, global population exposure to the aedes aegypti mosquito, and U.S. mortality from extreme heat events. Future BRACE efforts may add additional sectors and scenarios and could have a more substantial regional or city focus. Learn more about the BRACE 1.5 project.
BRACE in the News
BRACE authors have given or are planning talks on their analyses at numerous venues. View a list of BRACE talks, and watch an NCAR seminar presentation by Brian O'Neill on the BRACE project.
Several BRACE authors presented their work at the international scientific conference, "Our Common Future under Climate Change," in Paris in July 2015.