Lecture 6: Desertification 2 Flashcards
The scale of the problem : global desertification assessments
World Desertification Map (1977) UNCOD (UNEP, FAO, UNESCO, WMO). Using bioclimatic criteria, inherent vulnerability of the Earth and animal/human pressure. Soil map+veg map+population density map. Transparent map overlay
UNEP (1984) Plan of action to combat desertification (PACD) map.
UNEP/ISRIC (1990) International Soil Reference and Information Centre.
World Desertification Atlas (UNEP, 1992). Using computer GIS of factors e.g. soil, veg, population
The scale of the problem : global desertification assessments- problems
lack of data
simplicity of causal factors
complexity of feedbacks unaccounted for
vested interest - hype and alarmist.
not particularly useful in mitigation studies.
no account of cultural and economic context
very little info on causes and change over time
GLADA – Global Land Degradation Assessment in Drylands, 2003
Remote sensing analysis of what has actually happened
Based on change in NDVI (vegetation vigour) 1981-2003
Productivity decline
RUE
Bright spots
Processes of Desertification
Aridification (positive feedback)
Soil erosion and soil degradation (positive feedback)
Changes to infiltration/runoff partitioning (runoff)
Salinisation of soil and groundwater
Loss of soil fertility (because of erosion)
Declining productivity and veg. cover (as a result of the above, positive feedback)
Soil erosion and soil degradation
Rainsplash erosion Wash erosion Rill, gully erosion Wind erosion Dependent on : Erosivity (flow concentration) soil erodibility Slope angle Vegetation protection
SOLUTIONS: UNCCD - United Nations Convention to Combat Desertification
47.2% of earth’s territory is dryland; 1.2 billion inhabitants; many impoverished;
UNCCD adopted in 1994 to promote measures for combating desertification and to facilitate international cooperation;
UNCCD with 192 members;
More than 60 countries have adopted national action programmes;
Sub-regional and regional cooperation has been promoted through action programmes;
Promoting cooperation on scientific and technical matters through UNCCD Group of Experts and Committee on Science and Technology
Global Environment Facility (GEF) designated as a financing mechanism; 1.1 billion USD was allocated in 2012-2013
Measures for combating desertification & mitigating drought impacts
Biophysical aspects
Water resource management
Sustainable forest management/reforestation
Sustainable agriculture development
Biodiversity conservation
Climate change mitigation
Socio-economic aspects
Poverty eradication
Desertification control and drought mitigation measures – Early warning systems and their response measures
Prediction of desertification/drought- short term
water conservation- supply and watering for irrigation
conversion to water use efficient/drought resistant crops (medium term)
culling/disposal of
fallowing farmland
reforestation/ecosystem (long term)
legislation on the land owners responsibility for combatting desertification/ mitigating droughts (long term)
