CCEM stands for “coupling coarse earth models”. It is an extension to the IAM  (Integrated Assessment Model) concept - computer simulation of the coupling between energy, ecomnomy, and climate - that became famous thanks to the MIT “Limits to Growth” model and William Nordhaus DICE model. CCEM's originality stems from : making beliefs explicit, a finer-grain analysis of energy/economy coupling, together with an extension “warming to impact to feedback” retroaction loop that is often overlooked in IAMs. 


Purpose of CCEM

CCEM (Coupling Coarse Earth Models) is a simulation model representing the earth as a complex system and focusing on feedback loops associated with global warming. CCEM combines five simpler models, addressing energy availability, economic adjustment to energy scarcity, energy transition, global economy and CO2 emissions, and the impact of CO2 emissions on warming and society. The model aims to make implicit beliefs explicit and demonstrate that the same mental model can support various viewpoints by changing beliefs associated with "known unknowns." Five "known unknowns" include the future availability and cost of energy, energy needs and affordability for the economy, the speed of energy substitution, expected GDP growth, and the economic and societal consequences of global warming. These "known unknowns" have no consensus answers but making them explicit in models can help clarify differences in conclusions based on varying assumptions. CCEM, as an Integrated Assessment Model (IAM), enriches the feedback loop from global warming to the energy/economy system by representing the impacts of global warming and the associated retroactions. The model introduces a "pain factor" as a non-linear trigger for redirection, accounting for pain from warming, economic results, and energy shortages. It emphasizes that the complex system of energy, economy, climate, and society will evolve chaotically through redirections, making forecasting and planning difficult 


CCEM is the combination of five simpler model that represent energy production, energy consumption, energy transition, world economy and ecological redirection

CCEM makes explicit the hypotheses (inputs to the model) that are "known unknowns":  size and availability of energy sources, speed of adaptation, impact of scarcity, global warming damages ....

Energy transition requires to build new renewable energy sources and to shift energy usage from one primary source to another through vectors such as electricty or hydrogen. The "viscosity" of such changes is a key parameter of CCEM.

the concept of "Redirection"  recognizes the unpredictable and chaotic evolution of the interconnected energy, economy, climate, and society systems. Evolution is likely to be a non-linear series of reaction to crises.