The processes through which the landscape emerges. Earth’s landscapes reflect the interaction of climate, tectonics, and denudational processes operating over a wide range of spatial and temporal scales; these processes can be considered catastrophic or continuous, depending on the timescale of observation or interest.

Perron and Fagherazzi (2012) ESPL 37, 1, 52 suggest a sequence of landscape evolution. Firstly, variability in initial conditions can give rise to steady-state landscapes in which the characteristics of individual landforms vary about the mean, even in a homogeneous system with constant forcing. Secondly, landforms can have a range of mean equilibrium dimensions, either because different initial conditions evolve to different ‘attractor’ states, or because landscapes evolving from different initial conditions towards a single state converge too slowly to reach equilibrium under natural conditions. Thirdly, a landscape that experiences a perturbation or a change in process may begin to evolve towards a different equilibrium state, potentially leading to hysteresis or rapid changes in topography. See Himsah and Korup (2012) ESPL 37, 2, 249 for an overview of key themes in landscape evolution.

A landscape evolution model is a mathematical theory describing how the actions of various geomorphic processes drive and are driven by the evolution of topography over time. Tucker and Hancock (2010) ESPL 35, 1, 28 provide a useful summary. Dymond and Rose (2011) Geomorph. 132, 1–2, 29 offer an alternative phenomenological approach to modelling landscape evolution, and compare their model to the highly erodible Waipaoa catchment in New Zealand. There is good agreement between the predicted and observed topography.