In response to my post yesterday on the Klein Goldewijk et al paper, Dallas Staley alerted me to the following related paper.
Erle C. Ellis, Kees Klein Goldewijk, Stefan Siebert, Deborah Lightman and Navin Ramankutty, 2010: Anthropogenic transformation of the biomes, 1700 to 2000. Global Ecology and Biogeography, (Global Ecol. Biogeogr.) (2010) 19, 589–606.
The abstract reads
Aim To map and characterize anthropogenic transformation of the terrestrial biosphere before and during the Industrial Revolution, from 1700 to 2000. Location Global.
Methods Anthropogenic biomes (anthromes) were mapped for 1700, 1800, 1900 and 2000 using a rule-based anthrome classification model applied to gridded global data for human population density and land use. Anthropogenic transformation of terrestrial biomes was then characterized by map comparisons at century intervals.
Results In 1700, nearly half of the terrestrial biosphere was wild, without human settlements or substantial land use. Most of the remainder was in a seminatural state (45%) having only minor use for agriculture and settlements. By 2000, the opposite was true, with the majority of the biosphere in agricultural and settled anthromes, less than 20% seminatural and only a quarter left wild. Anthropogenic transformation of the biosphere during the Industrial Revolution resulted about equally from land-use expansion into wildlands and intensification of land use within seminatural anthromes. Transformation pathways differed strongly between biomes and regions,with some remaining mostly wild but with the majority almost completely transformed into rangelands, croplands and villages. In the process of transforming almost 39% of earth’s total ice-free surface into agricultural land and settlements, an additional 37% of global land without such use has become embedded within agricultural and settled anthromes.
Main conclusions Between 1700 and 2000, the terrestrial biosphere made the critical transition from mostly wild to mostly anthropogenic, passing the 50% mark early in the 20th century. At present, and ever more in the future, the form and process of terrestrial ecosystems in most biomes will be predominantly anthropogenic, the product of land use and other direct human interactions with ecosystems. Ecological research and conservation efforts in all but a few biomes would benefit from a primary focus on the novel remnant, recovering and managed ecosystems embedded within used lands.”
The conclusion contains the text
“There remain tremendous uncertainties in our understanding and ability to model even current global patterns of ecosystem function and biodiversity across the anthropogenic biosphere….We need human systems models that are as theoretically strong, predictive and useful as the best current biophysical models of natural biospheric pattern, process and dynamics, and we need these models to be coupled together to produce useful predictions of global ecological patterns, processes and dynamics….Given that most of the terrestrial biosphere is now anthropogenic, the future of all species, including ours, will depend on understanding and modelling the past, present and potential future ecology of our anthropogenic biosphere as we continue to directly alter and manage it.”
The concept of “ecosystem function” is, of course, just an integral component of the climate system. This recognition of the importance of the human role in ecosystem function is yet another example that illustrates the complexity of the climate, as well as the diversity of ways humans influence this system.