"The primary goal of the Community Earth System Model (CESM) project is to develop a state-of-the-art climate model and to use it to perform the best possible science to understand climate variability and global change. We will strive to build a CESM community of users who are interested in participating in this project."

Earth System Modeling Challenge

Identify and model the physical, chemical, biological, and human components that govern the climate system; quantify the certainties and uncertainties in Earth-system feedbacks on timescales up to centuries and longer.

Reliable information on expected climate conditions and impacts is needed to better inform societal decisions. Climate variability and change is determined by the functioning of the Earth’s physical, chemical, biological, and human systems and the interactions among them. To further understand climate system behavior, it is critical to maintain CESM as a world-class, community-based, state-of-the science, and comprehensive Earth System Model. This requirement depends on the translation of fundamental research on climate system processes into new and better parameterizations. It also necessitates the evaluation of model simulation behavior against process knowledge, observations and proxies from the distant past to the present.


  • Enhance capability for Earth system modeling of the physical climate system coupled with chemistry, biogeochemistry, biology and human systems.
  • Improve model representation of Earth system processes through the incorporation of new components, parameterizations and dynamical cores.
  • Use existing and new observations to test Earth system models at a process level and quantify the relative importance of different feedbacks.
  • Enable CESM community to conduct competitive climate research on a full range of computing platforms, through specific software developments and by hosting visitors and training tutorials.
  • Provide relevant datasets to the greater climate research community, accompanied by the collective knowledge gained from our experience.
  • Contribute knowledge to national and international assessments (e.g. IPCC).