BRACE 1.5 Project: Climate Change Impacts of 1.5°C and 2°C Warming

BRACE 1.5 logoIn 2015, 195 countries negotiated the Paris Agreement on climate change, which set long-term goals of limiting global mean warming to well below 2°C, and possibly 1.5°C. Sanderson et al. (2017) recently completed the first set of global climate model simulations with NCAR's Community Earth System Model (CESM) explicitly designed to meet those targets for use by the research community. The Benefits of Reduced Anthropogenic Climate changE (BRACE) 1.5 project builds on the recently completed original BRACE project, which examined the difference in impacts between two higher scenarios resulting in about 2.5°C and 3.7°C warming by late this century.

graphic from Sanderson et al. showing global average temperature pathways for the three temperature scenariosBRACE 1.5 aims to analyze impacts at 1.5°C and 2°C warming, to understand whether impacts differ substantially between the two climate scenarios. Approaches include direct analysis of differences in physical climate outcomes, assessment of methods for emulating 1.5°C and 2°C climate scenarios,economic analysis of agricultural impacts, both a process-based and an empirical crop model, a model of spatial population change, and models of potential health impacts. Results will help inform the ongoing Intergovernmental Panel on Climate Change (IPCC) Special Report on impacts of 1.5°C warming, as well as the larger scientific literature on the impacts of low warming scenarios. 

Special collection on Climate Change Impacts of 1.5°C and 2°C Warming

A special collection on "Climate Change Impacts of 1.5°C and 2°C Warming" is in progress for the journal Environmental Research Letters. Papers for the collection include:

  • Economic and biophysical impacts on agriculture under 1.5°C and 2°C warming (Ren X., Lu Y., O'Neill B.C., Weitzel M.)
  • Differences, or lack thereof, in wheat and maize yields under three low-warming scenarios (Tebaldi C., Lobell D.)
  • Changes in a suite of indicators of extreme temperature and precipitation under 1.5 and 2 degrees warming (Aerenson T., Tebaldi C., Sanderson B., Lamarque J-F.)
  • Is 1.5°C just three quarters of 2°C? Approximating low warming scenarios by higher ones (Tebaldi C., Knutti R.)
  • Projections of US heat wave-related mortality under 1.5°C and 2°C warming (Anderson G.B., et al.).
  • Avoided Economic impacts of energy demand changes by 1.5 and 2 °C climate stabilization (Chan, Fujimori, et al.)
  • Global exposure and vulnerability to multi-sector climate change hotspots (Byers E., Gidden M., Burek P., Ebi K., Greve P., Havlik P., Johnson N., Kahil T., Krey V., Langan S., Leclère D., Obersteiner M., Palazzo A., Pachauri S., Parkinson S., Rao N., Rogelj J., Satoh Y., Wada Y., Willaarts B., Riahi K.)

Related papers

Many of the BRACE 1.5 papers draw on climate model simulations documented in: Sanderson B.M., Xu Y., Tebaldi C., Wehner M., O'Neill B.C., Jahn A., Pendergrass A.G., Lehner F., Strand W.G., Lin L., Knutti R., and Lamarque J.F., 2017. Community climate simulations to assess avoided impacts in 1.5 and 2°C futures. Earth System Dynamics, 8, 827-847. DOI: 10.5194/esd-8-827-2017.

A related paper was also published in Geophysical Research Letters: Lehner F., Coats S., Stocker T.F., Pendergrass A.G., Sanderson B.M., Raible C.C., Smerdon J.E. 2017. Projected drought risk in 1.5°C and 2°C warmer climates. Geophysical Research Letters, 44, 7419–7428. DOI: 10.1002/2017GL074117.