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Earth Observation Research Cluster

WASCAL

  • Subject: Climate change and land use
  • Study site: Africa
  • Funding: Federal Ministry of Education and Research

Figure 1: Shows the WASCAL focus region, the Sudanian savanna belt in West Africa, as a satellite picture

The Sudanian Savanna of West Africa has been identified as one of the most vulnerable to climate change. Climate models have predicted an increase in the occurrence of droughts and floods by the period 2080-2099. This is as a result of an increase in temperature between 3-4°C and the occurrence of higher rainfall intensity and variability. This situation will drastically increase food insecurity and poverty largely due to the reliance of majority of the populace on rainfed agriculture. In order to forestall these eminent effects of climate change, there is the need to formulate a rigorous and coherent climate change adaptation and mitigation policy based on a sound understanding of the climate and its linkages with other factors such as land use. But the exact effects of climate change on the region are still poorly understood. This poor understanding is due to reasons such as, poor data infrastructure, lack of scientific capacity and limited research on climate change.

In view of the above challenges, the West African Science Service Center on Climate Change and Adapted Land Use (WASCAL) aims to, among other things, strengthen the regional capabilities,

a) to understand the climate change dynamics and implications on ecosystems and society using scientific up-to-date research; and

b) to improve the scientific knowledge base for improved decision making in regard to climate change menaces on ecosystems service provisions and livelihoods.

WASCAL is coordinated by the Center for Development Research (ZEF) of the University of Bonn, and will be implemented in ten West African countries. Collaboration between numerous German and West African Universities will enable the transfer of technology from German scientist to their West African counterparts. WASCAL is sponsored by the German BMBF (Project reference: 01LG1001A) and is currently in the preparatory phase.

The Remote Sensing Department of the University of Wuerzburg is a partner in the WASCAL project and coordinator of the research work package - “Remote sensing based analysis of land cover and land use change pathways and drivers”. The aim of this research work package is to map and monitor spatial explicit land use patterns and dynamics in the Sudanian Savanna of West Africa. Special emphasis will be placed on agricultural land use and the adverse effects of climate change on it and vice versa.

Multi-temporal, spatial and spectral resolution remotely sensed images (e.g. Landsat, RapidEye, MODIS, and possibly Nigeria-Sat) will be assembled to map land use change pathways in the heterogeneous agricultural landscape of West Africa. Assembled satellite images will be temporally aligned with critical cropping stages such as tillage, sowing, flowering, grain filling, growing, maximum phenology, harvest and fallow period. Information on these critical cropping stages will be obtained through field surveys during which an adapted FAO LCCS (Land Cover Classification System) field sampling protocol will be used. Alignment of multi-temporal satellite images to the agro-ecological calendar will enable the derivation, and or extraction, of crop phonological metrics. Through assimilation of the temporal behavior of crops and cropping systems, the separability for instance between irrigated agriculture and rainfed agriculture and between croplands and natural vegetation will enable the accurate mapping of the spatio-temporal changes in crops and cropping systems in the region. Detailed analysis will be conducted at a watershed level (100 – 200km2), while knowledge gained at this level will serve as the basis for up-scaling to the wider Sudanian Savanna region. The accurate information on the actual changes in land use is critical in understanding the drivers of this change, and hence will be utilized to help formulate knowledge-based adaptation and mitigation polices.

The Department of Remote Sensing is also the German counterpart for the WASCAL Graduate School on ‘climate change and land use’ that is being facilitated through the Kwame Nkrumah University of Science and Technology (KNUST) in Kumasi, Ghana.