Climate Change and Global Agricultural Potential: A Case Study of Nigeria

Voortman RL, Sonneveld BGJS, Langeveld JWA, Fischer G, & van Velthuizen HT (1999). Climate Change and Global Agricultural Potential: A Case Study of Nigeria. Centre for World Food Studies, International Institute for Applied Systems Analysis (IIASA) , Amsterdam, Netherlands; IIASA, Laxenburg, Austria. DOI:wp-99-06.

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Abstract

This study presents a spatially specific assessment of the potential impacts of the greenhouse effect on crop production potentials and land productivity in Nigeria. To this effect a large number of scenarios were used consisting of results from experiments with General Circulation
Models (GCM’s) as well as sensitivity scenarios in which single variables were changed. Each scenario is characterised by level of increase of atmospheric CO2, change of stomatal resistance and climate change in terms of temperatures, rainfall and radiation. The effects of such changes have been assessed within the framework of the agro-ecological zones methodology, that was adapted and expanded for the purpose of the present study. Climate changes are applied to observed baseline conditions for the period 1960-1990 and simulated climate is used in combination with soil and landform conditions, plant physiological adaptations to elevated CO2 and a number of sustainability criteria (e.g. fallow period requirements) to calculate crop production potentials and land productivity. Scenario outputs are compared with current conditions to assess potential impacts and sensitivity of agricultural production to global change phenomena.
A large number of maps and tables summarise the potential impacts on crop production potentials and land productivity. The low predictive value of GCM’s and large differences between GCM’s only allow to draw conclusions of policy relevance taking into account a cautionary bandwidth of possible events. The Nigerian middle belt will hardly be affected because changes are likely to be limited and farmers may adapt by choosing other crop varieties.
The north of the country is very sensitive to changes of climate and the prevailing crops show little response to elevated CO2 levels. GCM’s are consistent in indicating climatic changes that lower land suitability for perennial crops in the south. The south-west, with a bimodal rainfall tendency, is particularly sensitive to climate change. Here small changes in scenario may cause either one long growing period or two short ones. However, lower productivity due to climate change, if any, is likely to be more than compensated by the effects of enhanced CO2 levels.
Prevalent crops in the south have a C3 photosynthesis pathway, that is responsive to enhanced
CO2 levels, which is likely to result in increased of productivity of annual crops such as yams and cassava. Global change may thus exacerbate the current disparities of crop production potentials between the north and the south of the country.

Item Type: Other
Research Programs: Modeling Land-Use and Land-Cover Changes (LUC)
Depositing User: IIASA Import
Date Deposited: 15 Jan 2016 02:09
Last Modified: 20 Jul 2017 16:29
URI: http://pure.iiasa.ac.at/5484

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