Crop response to climate change in southern Africa: A comprehensive review

Abstract

Concern over future food security in southern Africa has led to various studies that assess the impact of climate change on crops in the region. The results vary according to applied methods and tools. This study reviewed and consolidated results from 19 recent studies which quantitatively project the impact of climate change on crops for the 21 st century in southern Africa. Results were assessed according to crop modelling techniques, which included process-based, statistical and economic (Ricardian) modelling. Studies were assessed for their reporting and recommendations concerning adaptation and CO 2 fertilisation. Results suggest that the aggregate impact of climate change on crops in southern Africa will be negative. Maize yields are projected to decline on average by 18%. The collective impact of climate change on all crop yields shows a median decline of-11% and-14% respectively under process-based and statistical methodologies. Median impacts show declining crop yields through the 21 st century. No significant change in the near future,-18% for the mid century and-30% for late century. GCM driven Ricardian projections are highly variable. However, uniform climate scenarios project a median revenue decline. Notwithstanding the challenges of such a review; lack of data, bias towards reported methods and tools, uncertainty, scale etc., results indicate that climate change may impact southern African crops in important ways thereby making adaptation essential. Adaptation and CO 2 fertilisation could potentially moderate the negative impacts of climate change. This implies a need for studies into future adaptation that consider CO 2 fertilisation.

Impacts of Climate Variability and Change on Rainfed Sorghum and Maize: Implications for Food Security Policy in Tanzania

“…Other studies in SSA show some evidence of negative climate change impact on crop yield for major staple cereal food crops like maize, sorghum and millet (Schlenker & Lobell, 2010;Knox, Hess, Daccache, & Wheeler, 2012;Berg, De Noblet-Ducoudre, Sultan, Lengaigne, & Guimberteau, 2013;Zinyengere, Crespo, & Hachigonta, 2013;Waha, Müller, & Rolinski, 2013). These studies give generalized and broad conclusions about the impact of climate change which are not manifest in crop production to address increased food security concerns.…”

Climate and southern Africa's water–energy–food nexus

“…Some crop models simulate sizable yield losses for southern Africa 47 , suggesting that the region's food system could be particularly vulnerable to climate change 48 . However, differences in climate scenarios, impact models, spatial and temporal scales, and processes represented restrict our ability to reliably define impacts for specific sectors and, importantly, secondary effects across the water-energy-food nexus.…”

In the Presence of Climate Change, the Use of Fertilizers and the Effect of Income on Agricultural Emissions

“…Moreover, the literature shows global and country-level specific studies investigating crop-switching, the Ricardian method, and temperature affects under future climate scenarios [3][4][5]. Zinyengere, Crespo and Hachigonta [6] and Chen et al [7] provide extensive literature reviews on crop-response projections for South Africa and China, respectively. Existing studies with the Ricardian method assume that farmers alter their inputs, outputs, and practices in response to climate change [3].…”

“…This suggests that their results may be spurious and hence may have indicated incorrect EKC turning points. More recent studies have looked into the causal relationship between income and CO 2 and SO 2 emissions by including energy consumption in their models [6,32,37,38].…”