Integrated Earth System Model – iESM

The iESM project is a collaboration between three national laboratories to create a first generation earth system model with a fully integrated human systems component. We are coupling the GCAM integrated assessment model with the CESM earth system model. The GCAM integrated assessment model is housed and developed at PNNL and is used in the coupled model to represent human activities affecting land use and greenhouse gas emissions. The CESM teams include a group at ORNL working with the Community Land Model and a team at LBNL working with the full CESM model.  The objective is to produce a fully integrated model code coupling these elements, and to exercise the coupled system to explore the future evolution of bioenergy systems, hydrology, climate adaptation and climate mitigation. The iESM is a 5 year project begun in 2009 and sponsored by the US Department of Energy Office of Science. 

Why This Is Important

  • In the present world emissions mitigation analysis is undertaken under the assumption that the climate is not changing.  E.g. crop yields are unchanged, water resources are unchanged, and energy systems don’t have to cope with a changing climate.
  • Climate impacts analysis is undertaken with the assumption that no resources are being diverted to address climate change.  E.g. no land is being used for reforestation, no land is being used to grow bioenergy, and energy prices are unchanged.
  • Climate simulations are done under specified land-cover/land-use changes (if any), e.g. no land is being used for bioenergy, reforestation, feeding an additional 3-4 billion people, and energy use is only considered indirectly via emissions.
  • The development of an iESM means that fully consistent analysis of potential future climate change, emissions mitigation options, and impacts and adaptation options will be possible.

In collaboration with: