Date of Completion

1-14-2016

Embargo Period

1-14-2016

Keywords

Climate Change Impact, Crop Yield, Land Use Modeling, Climate Modleing, West Africa

Major Advisor

Dr. Guiling Wang

Associate Advisor

Dr. Chuanrong Zhang

Associate Advisor

Dr. Richard Anyah

Associate Advisor

Dr. Amy Burnicki

Associate Advisor

Dr. Liangzhi You

Field of Study

Environmental Engineering

Degree

Doctor of Philosophy

Open Access

Open Access

Abstract

Projection of climate change impact on anthropogenic land use and the resulting feedback to the regional climate in West Africa is the core focus of this research. In the first part, we evaluate climate change impact on future crop yield, a key factor affecting agricultural land use in a region. Using a process-based crop model at a regional scale, we project future changes in cereal crop yields as a result of climate change for the West African countries. Without agricultural adaptation, the long-term mean of crop yield is projected to decrease in most of the countries by the middle of the century, while the inter-annual variability of yield increases significantly. This increase of yield variability is attributed to an increase of inter-annual variability of growing season temperature and/or precipitation in future climate.

Using the projected crop yield as an input, we then develop a cropland projection model (LandPro_Crop), based on a balance between food supply and demand, to compare the contributions of climate change and socioeconomic development to potential future changes of agricultural land use in West Africa. The model accounts for the impact of socioeconomic drivers on the demand side and the impact of climate-induced crop yield changes on the supply side. The climate-induced decrease of crop yield together with increase of food demand are found to cause a significant increase in agricultural land use at the expense of forest and grassland by the mid-century. The increase of agricultural land use is primarily climate-driven in the western part of West Africa and socioeconomically driven in the eastern part. Analysis of multiple “what-if” scenarios suggests that human adaptation characterized by science-informed decision making can potentially minimize land use changes in many parts of the region.

Using the future land use maps projected by LandPro_Crop, we perform multiple future-climate experiments to assess the land use-climate interactions in West Africa. We employ an asynchronous coupling between the land use model and the regional climate model RegCM 4.3.4-CLM 4.5 to capture the transient trends in dynamics of agricultural land use and its implication on the regional climate projections. Projections from the climate experiments indicate that land use feedback could significantly affect the future climate changes in West Africa. Projected change in climate variables caused by the greenhouse gas forcing would be modified in many cases because of the changes in leaf area index and surface albedo resulting from the future crop area expansion replacing natural vegetation.

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