Rainfall variability and trends in semi-arid Botswana: Implications for climate change adaptation policy

Rainfall variability is an important feature of semi-arid climates, and climate change is likely to increase that variability in many of these regions. An understanding of rainfall variability and trends in that variability is needed to help vulnerable dryland agriculturalists and policymakers address current climate variation and future climate change. The goals of this paper are to examine this climatic phenomenon in semi-arid Botswana, to investigate these results for signs of climate change, and to explore the policy implications for climate adaptation. To reach these goals, the paper determines rainfall variability and monthly and annual trends in that variability. The results agree with earlier work showing gradients in rainfall and rainfall variability across Botswana. The results also identify a trend towards decreased rainfall throughout the nation, which is associated with decreases in the number of rainy days. Both the drying trend and decrease in rainy days agree with climate change projections for southern Africa. The paper discusses policies that the government could adopt to help its farmers adapt to climate change. (C) 2009 Elsevier Ltd. All rights reserved.