Geoscience Reference
In-Depth Information
Modelling land dynamics
The advances in land-change modelling have matched those in remote-sensing
observations, driven in large part the demand for spatially (geographically) explicit
model outputs (Lambin, 1994; Veldkamp and Lambin, 2001; Agarwal et al., 2002).
While little agreement exists regarding model taxonomies, the array of 'integrated'
modelling efforts - combining human and environmental variables to address both
human and environment outcomes - cross cuts ecology (Liu, 2001), economics
(Kaimowitz and Angelsen, 1998; Irwin and Geoghegan, 2001) and the interdisci-
plinary communities (Liverman et al., 1998; Veldkamp and Lambin, 2001). Both
empirical and theoretical models have been directed to projecting land-use/cover
changes down to the pixel level (e.g., Veldkamp and Fresco, 1996; Liverman et al.
1998; Bell and Bockstael, 2000; Walker et al., 2004), as have agent-based models
(Parker et al., 2003; Manson and Evans, 2007). Modelling efforts address the full
array of new GIScience methods (Walsh et al., 1999; Brown et al., 2000; Pijanowski
et al., 2002), are applied from frontier to urban settings (Batty et al., 1997; Geoghe-
gan et al., 2005) and explore environmental or land-cover feedbacks on land use
(Verburg, 2006). The spatially explicit nature of the land-change modelling has also
triggered advances in the measures of the accuracy of the outcomes (e.g., Pontius,
2002).
Coupling and synthesis: future pathways
The research captured in the headings above has not yet reached its maturity, in part
owing to the complexity of land system dynamics and the trans-disciplinary nature
of integrated assessments, which carry with them an array of analytical problems
(Rindfuss et al., 2004). Major advances are expected in each category of research,
however, especially regarding observation-monitoring and modelling, if only because
of the level of research expenditures devoted to them internationally.
Global environmental change and sustainability science, however, place demands
on the land-change community to move rapidly towards synthesis products and
assessments (e.g., Turner et al., 2003a); that is, to move from single 'sector' analyses,
such as 'hot spots' of xeric land degradation or losses in biotic diversity, to issues
of total system resilience-vulnerability (Adger, 2000; Downing et al., 2000; Turner
et al., 2003b) and sustainability (Schellnhuber et al., 1997; Berkes et al., 2003; Clark
et al., 2004). This orientation, in turn, demands that land be treated as coupled
human-environment or social-ecological systems in which the synergy of the sub-
systems sets the conditions of the response of both subsystems to external drivers
(Cutter et al., 2000; Luers et al., 2003; Turner et al., 2003c), as well as the conse-
quences of the coupled system for the earth system at large (e.g., carbon and nitro-
gen cycles).
Implications for Geography
From the IPCC to the ESSP, many geographers have been instrumental in the devel-
opment of global environmental change and sustainability research agenda-setting
and research efforts (Kates et al. 2001; Liverman et al., 2004), in part owing to the
long-standing, geographic traditions of integrated approaches to and synthesis
understanding of earth system processes and human-environment relationships.
