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Title: Community climate simulations to assess avoided impacts in 1.5 and 2 °C futures

The Paris Agreement of December 2015 stated a goal to pursue efforts to keep global temperatures below 1.5 °C above preindustrial levels and well below 2 °C. The IPCC was charged with assessing climate impacts at these temperature levels, but fully coupled equilibrium climate simulations do not currently exist to inform such assessments. Here, we produce a set of scenarios using a simple model designed to achieve long-term 1.5 and 2 °C temperatures in a stable climate. These scenarios are then used to produce century-scale ensemble simulations using the Community Earth System Model, providing impact-relevant long-term climate data for stabilization pathways at 1.5 and 2 °C levels and an overshoot 1.5 °C case, which are realized (for the 21st century) in the coupled model and are freely available to the community. We also describe the design of the simulations and a brief overview of their impact-relevant climate response. Exceedance of historical record temperature occurs with 60 % greater frequency in the 2 °C climate than in a 1.5 °C climate aggregated globally, and with twice the frequency in equatorial and arid regions. Extreme precipitation intensity is statistically significantly higher in a 2.0 °C climate than a 1.5 °C climate in some specific regions (but not all). The modelmore » exhibits large differences in the Arctic, which is ice-free with a frequency of 1 in 3 years in the 2.0 °C scenario, and 1 in 40 years in the 1.5 °C scenario. Significance of impact differences with respect to multi-model variability is not assessed.« less
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  1. National Center for Atmospheric Research, Boulder, CO (United States)
  2. Texas A & M Univ., College Station, TX (United States). Dept. of Atmospheric Sciences
  3. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  4. Univ. of Colorado, Boulder, CO (United States). Dept. of Atmospheric and Oceanic Sciences, Inst. of Arctic and Alpine Research
  5. Sun Yat-Sen Univ., Guangzhou, (China). School of Atmospheric Sciences
  6. National Center for Atmospheric Research, Boulder, CO (United States); ETH, Zurich (Switzerland). Inst. for Atmospheric and Climate Science
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Earth System Dynamics (Online)
Additional Journal Information:
Journal Name: Earth System Dynamics (Online); Journal Volume: 8; Journal Issue: 3; Journal ID: ISSN 2190-4987
European Geosciences Union
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
OSTI Identifier: