How to Quantify Human-environment Interactions in the Past: A Global Historical Land Use Data Set for the Holocene

Abstract:

Land use plays an important role in the climate system. Many ecosystem processes are directly or indirectly climate driven, and together with human driven land use changes, they determine how the land surface will evolve through time. To assess the effects of land cover changes on the climate system, models are required which are capable of simulating interactions between the involved components of the Earth system. Since driving forces for global environmental change differ among regions, a geographically (spatially) explicit modeling approach is called for, so that it can be incorporated in global and regional (climate and/or biophysical) change models in order to enhance our understanding of the underlying processes and thus improving future projections.

Some researchers suggest that mankind has shifted from living in the Holocene (~emergence of agriculture) into the Anthropocene (~humans capable of changing the Earth’ atmosphere) since the start of the Industrial Revolution. But in the light of the sheer size and magnitude of some historical land use changes (e.g. the Black Plague in the 14^th century and the aftermath of the Colombian Exchange in the 16^th century), some believe that this point might have occurred earlier in time. There are still many uncertainties and gaps in our knowledge about the importance of land use (change) in the global biogeochemical cycle, and it is crucial that researchers from other disciplines are involved in decreasing the uncertainties.

Thus, integrated records of the co-evolving human-environment system over millennia are needed to provide a basis for a deeper understanding of the present and for forecasting the future. This requires the major task of assembling and integrating regional and global historical, archaeological, and paleo-environmental records. Humans cannot predict the future.

Here I present a tool for such long term global change studies; it is the latest update (v 3.2) of the History Database of the Global Environment (HYDE), which tries to incorporate many of these cross-disciplinary records and create thus new and more accurate estimates of the underlying demographic and agricultural driving factors for the whole Holocene. Estimates include population, cropland, pasture, rangeland, irrigation, rice, and built-up area.