Atmospheric Sciences & Global Change
A Whole Earth Model
Tracking interactions between the Earth's air, land, ocean, ice, chemistry and biology
The Community Earth System Model simulates a complete and complex representation of all components of the Earth System—air, land, water, and ice. Earth system models are important to provide information that will help future energy decisions. Enlarge Image.
Results: A large collaborative community of researchers, including scientists at Pacific Northwest National Laboratory, found a way to simulate a complete and complex representation of all components of the Earth System—air, land, water, and ice. The resulting Community Earth System Model (CESM) produces much more realistic simulations of many aspects of the climate system. The model now includes an improved representation of clouds, atmospheric particles, and the transfer of radiant energy. For the first time, the CESM represents aerosol particle effects on clouds, which results in a more realistic simulation of the surface warming during the last century.
"The U.S. Department of Energy Office of Science funding contributed to a major overhaul of the atmospheric component of the CESM," said PNNL atmospheric scientist Dr. Steve Ghan. "This improvement means that this global climate model will provide more realistic information to inform future energy policy decisions."
Why It Matters: Computer models of the Earth are necessary tools for projecting future effects of increased carbon dioxide in the atmosphere. Humans are affecting the levels of these emissions by burning fossil fuels such as coal, oil and natural gas for heating, transportation and manufacturing. By using large volumes of already collected data to evaluate the simulation of the climate in the past, the community of scientists that developed the CESM showed that the model is more likely to realistically simulate the climate response to future emissions. This information is essential to make informed decisions on future energy sources and use.
Methods: The model is the product of a huge community effort to use satellite and surface-based collected data, quality weather data, and measurements from intensive field studies to test each model component-atmosphere, land, ocean, sea ice, and land ice-separately first and then coupled together.
What's Next? Climate simulations by the CESM have been analyzed for the upcoming report of the Intergovernmental Panel on Climate Change (IPCC). The full behavior of the CESM is not fully understood, and its full potential has yet to be exercised. Applications to paleo-simulations of the onset and end of the Pleistocene ice age and to projections of future sea level rise as Greenland melts are planned in the next few years. The model is available to the scientific community to conduct fundamental research into the Earth's past, present and future climate states.
Sponsors: Development of the CESM was partially funded by the U.S. Department of Energy (DOE) Office of Science Scientific Discovery through Advanced Computing (SciDAC) Program and by the Office of Science Earth System Modeling Program. The CESM project is supported by the National Science Foundation (NSF) and the U.S. DOE Office of Science Biological and Environmental Research program. Computing resources were provided by the National Center for Atmospheric Research (NCAR) Computational and Information Systems Laboratory, sponsored by NSF and other agencies, and the Oak Ridge Leadership Computing Facility at Oak Ridge National Laboratory.
Research Team: James W. Hurrell, M.M. Holland, P.R. Gent, J. E. Kay, J.F. Lamarque, W.G. Large, D. Lawrence, K. Lindsay, M.D. Long, D.R. Marsh, R.B. Neale, M. Vertenstein and J. Kiel, the National Center for Atmospheric Research; Steve Ghan and Phil Rasch, PNNL; P. J. Kushner, University of Toronto Canada; W. H. Lipscomb, Los Alamos National Laboratory; N. Mahowald, Cornell University; S. Vavrus, University of Wisconsin-Madison; D. Bader, Lawrence Livermore National Laboratory; W.D. Collins, Lawrence Berkeley National Laboratory; J.J. Hack, Oak Ridge National Laboratory; and S. Marshall, University of Calgary Canada.
Research Area: Climate & Earth System Science
Reference: Hurrell JW, MM Holland, S Ghan, J Kay, JF Lamarque, D Lawrence, K Lindsey, W Lipscomb, M Long, N Mahowald, D Marsh, R Neale, P Rasch, D Bader, WD Collins, PR Gent, JJ Hack, J Kiehl, P Kushner, WG Large, S Marshall, S Vavrus and M Vertenstein. 2013. "The Community Earth System Model: A Framework for Collaborative Research." Bulletin of the American Meteorological Society 94(9):1339-1360. DOI: 10.1175/BAMS-D-12-00121.1