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LU-CDM, A Conceptual Model of Desertification

Författare:
  • Ulf Helldén (Professor)
Publiceringsår: 2008
Språk: Engelska
Dokumenttyp: Konferensbidrag

Sammanfattning

This paper presents a generic system dynamic model to simulate and analyze a desertification system and its stability for different desertification syndromes.

The study is one of many desertification related modelling approaches carried out by different project partners within the frames of DeSurvey (A Surveillance System for Assessing, Monitoring and Modelling Desertification; 2005-2010). DeSurvey is an EU FP6 Integrated Project (IP) on desertification considering the inter-action and importance of socio-economy, climate and landscape vulnerability to land degradation.

The model integrates socio-economic drivers with bio-physical drivers of land degradation and desertification. It is based on the UN and GEF definitions of desertification. It illustrates the concept of desertification through differential equations, simulation output graphics and through causal loop diagrams demonstrating the existing feed-back mechanisms. It may be useful for land use system stability/equilibrium condition analysis and for sustainable strategic land policy and management decision support.

The model relates population pressure and dynamics over time to the removal and availability of biomass resources. The population stock is described as a function of growth rate, death rate and resources dependent in and out migration of people. The relative growth rate of the stock of resources is modeled as a function of climate and exploitation pressure affecting soil erosion and water availability. Biomass recovery from serious degradation/desertification status follows the logistic growth function modified by population pressure, erosion and water availability conditions.

The conceptual desertification model is applied for the Sahelian syndrome using input data from the Sudan to illustrate a 150 years period (1900-2050). The model indicates that it is very difficult to generate irreversible desertification in a system where there is a free market and free population mobility unless serious climate change and/or extremely serious soil erosion creates long term wasteland conditions and ultimate land abandonment.

Disputation

Nyckelord

  • Earth and Environmental Sciences
  • Desertification
  • Land degradation
  • System dynamic modelling
  • Conceptual model

Övriga

Wengen Workshop on Global Change Research: Edition 2007; Climate Change and Desertification: Monitoring, Modelling and Forecasting
2014-09-11
Hotel Regina, Wengen, Switzerland
  • EU DG Research
Submitted
  • FP6, DeSurvey IP 2005-2010, A Surveillance System for Assessing and Monitoring Desertification
Yes
  • EU, FP6 DeSurvey, WP 1.3.3 LUS Vulnerability;Integration and Dynamic Systems modeling
  • not yet known

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