Southern Africa's 2012–13 Violent Storms: Role of Climate Change

AbstractThis study which sought to understand the phenomenal events surrounding numerous, intense and violent storms in southern Africa, was inspired by the unusually active 2012-2013 season. In addition to improving the Early warning system, the study supports the evaluation and calibration of the weather forecasting guidance NWP products and RCMs alike. The study also sought to investigate the role of Climate Change in the occurrence of these storms in addition to understanding the science behind them, the causes and possible return periods for better impact, vulnerability and adaptation studies as well as integration of Climate Risk Management practices like Weather Index Insurance and climate resilience planning into development. Preliminary analyses categorized Chivi storm as a Dry Macro-burst as the region experienced serious delayed onsets of rainfall and high temperatures, Chilonga and Mt Darwin as squall lines and nados respectively, whereas Bindura and Mberengwa cases were all Wet Macro-bursts. Density currents from nearby mountain ranges coupled with extreme temperature rises, influx of moisture into dry regions prior to these events were identified as the possible triggers which were aided by prolonged dry spells in the rain season. Rapid Climate Change is thought to have enhanced and prolonged the 2012-2013 storm activity which stretched until April which is cooler. Global warming which increases the atmospheric water vapour holding capacity, according to the Clausius-Clapeyron theory, also provides energy which fuels these violent storms. Thus as Climate Changes, the study hypothesize more intense storms, heavily impacting life, property and development

Changes in Climate Extremes and Their Effect on Maize (Zea mays L.) Suitability Over Southern Africa

Southern Africa has been identified as one of the hotspot areas of climate extremes increasing, at the same time many communities in the region are dependent on rain-fed agriculture, which is vulnerable to these rainfall and temperature extremes. The aim of this study is to understand changes in extreme indices during the agricultural season under climate change and how that affect the modeling of maize suitability in Southern Africa. We analyze the changes in rainfall and its extreme indices (consecutive dry days, heavy rain events and prolonged rainfall events), and temperature and its extreme indices (hot night temperatures, hot day temperatures and frequency of very hot days) from the past (1986–2014) to the future (2036–2064) and integrate these into a maize suitability model. Temperature extremes are projected to increase in both duration and intensity, particularly in the eastern parts of the region. Also, consecutive dry days are projected to increase over larger areas during the agricultural season, while rainfall will be less in sums, heavier in intensity and less prolonged in duration. Including extreme climate indices in maize suitability modeling improves the efficiency of the maize suitability model and shows more severe changes in maize suitability over Southern Africa than using season-long climatic variables. We conclude that changes in climate extremes will increase and complicate the livelihood-climate nexus in Southern Africa in the future, and therefore, a set of comprehensive adaptation options for the agricultural sector are needed. These include the use of heat, drought and high-intensity rainfall tolerant maize varieties, irrigation and/or soil water conservation techniques, and in some cases switching from maize to other crops