Introduction

This short note proposes a particular approach to integrating the human dimensions of global climate change with global climate models. It takes a similar approach to EMICs (Earth System Models of Intermediate Complexity), that is, a more balanced approach to integrating various elements of the earth system at a "sufficient" level of complexity (ie "good enough") rather than remaining at the behest of the "Tyranny of the Atmosphere" of the established global climate models.

HDMICs are intended to play an analogous role by trying to take a balanced but not too detailed (ie "good enough") view of how humans interact with the earth system. However, just as with global climate models we do not want to be necessarily be caught in the "Tyranny of Massive Agent-Based Models" since at least at this stage it would be a huge undertaking to construct massive ABMs (Agent Based Models) of the global aspects of the human activities that interact with global climate change. A more parsimonious approach is probably more appropriate at this stage.

One Suggested Approach

The following are the elements of one suggestion for constructing such a HDMIC, which uses ideas of complex networks, agent-based models and scaling relations from the complexity sciences:

1. The anthropocene is partitioned into relatively "homogeneous" regions, with the proviso that the (larger) urban centres are treated as separate regions since they possess an important and different dynamic to them. We can consider these regions as nodes in a complex network/s ... there may be a number of these networks based on the relationships we are interested in between the regions.
2. We take a macrosocial/macroecological approach to the network of regions and to the regions themselves, such as using scaling relations between say the size of the region and phenomena of interest. As a simple example, we know the distribution of cities (the set of urban nodes) follows a Zipf distribution.
3. As for urban centres we can make use of recent work by Bettencourt and others on different scaling relations in cities, both currently and historically. Such work is also found under the Urban Metabolism label. We can then estimate variables of interest based on the size of cities. And since global urbanization is currently such a pervasive trend, it behoves us to treat cities as important sites of interest.
4. This urban scaling work also relates to similar work by others say on Tsallis q statistics (which is gaining interest in the statistical mechanics of both extensive and non-extensive systems) and cities in history, etc.
5. Of course it is natural to forge the relationship between urban metabolism (and of course Regional Metabolism) and the industrial ecology focus on material flows and energy flows, as well as the work on the Physical Economy.
6. Population growth rates will drive the size and number of these nodes according to scaling and other relations, but probably will be constrained in some way by the physical economy.
7. From the scaling relationships we can then associate both ecological footprints and financial/economic footprints, thus forging a link to the earth system and economic general equilibrium models.

Refining the above ideas would be an important next step to assess the "intellectual feasibility" of the proposition proposed.