By Churchill Okonkwo
Beltsville Center for Climate System Observation (BCCSO), Howard University
The tremendous importance of water in society and nature underscores the necessity of understanding how a change in global climate is affecting the availability and variability of regional water resources. Lake Chad for instance, located in one of the poorest and most drought-prone regions of the world ÛÒ the Sahel region of sub Saharan Africa – has shrunk from around 25,000 square-kilometers in the early 1960s to less than 2,000 square kilometers today (Grove, 1996). The Sahel region today may receive just enough precipitation. The lessons from the current drought in Horn of Africa, however, is a reminder of the potential threat facing the more than 30 million inhabitants of the Lake Chad Basin (LCB).
The United Nations estimates that 12 million people have been affected in East Africa by the worst drought in more than half a century. The urgency of the humanitarian assistance needed to save more than 3 million internally displaced and starving populations (UN, 2011) has raised the question of reliability of early warning mechanisms and water question in drought prone regions of Africa.
Unlike Somalia, will an effective mechanism be put in place to detect onset of drought in LCB? Most importantly, what needs to be done to minimize adverse effects of drought in LCB? In this essay, scientific perspectives will be applied to explain and compare the complex nature of the current drought in Somalia and Lake Chad Basin (LCB). The similarities between hydro-meteorological variables in both cases were analyzed. The objective of the study is to provide a comparative analysis of spatial and temporal variability of drought indices in Somalia and LCB with the view to identifying trends and onset of drought. The result from this comparison will hopefully serve as timely input for policy makers in LCB and international organizations for sustainable water resources development and management in LCB
There are three unique similarities between Somalia and LCB. First is the striking similarity in the 30-year annual precipitation (Figure 1) from 1961 to 1990. There is a general southward increase in the mean 30-year annual precipitation in both regions of the basin. Second is the distribution of surface water bodies in both cases compared to the rest of the African continent (Figure 2). While the northeast and northwest regions are characterized by pertinent water bodies, the southern parts have a few perennial rivers that act as a lifeline to agricultural activities and human needs. The aridity index in both cases (Figure 3) provides a simple way to express the ratio of precipitation to evaporation, where a high aridity index means a humid climate and a low aridity index means an arid climate.
The third is the insurgence by Islamic militants that tend to capture the attention of the rest of the world much more than the threat of drought and famine. In Somalia, there is the Al-Shabab with links to al-Qaida while the Boko Haram operate in the southeast of LCB (Maiduguri, Nigeria) and are also linked with al-Qaida. The activities of these militants have captured the attention of international communities in the global fight against terrorism. The danger is that the socio-economic issues like the present drought in the Horn of Africa are getting secondary attention as a result. The question then is, like in Somalia, will the local policy makers in LCB and international community fail to detect onset of drought in LCB?
The difficulty in developing a definition to describe drought and an index to measure it is due to its diverse geographical and temporal distribution, the many scales drought operates in and the variety of disciples it affects. Despite these difficulties, McKee et al., (1993) developed an effective drought index ÛÒ the Standardized Precipitation Index (SPI) ÛÒ which facilitates temporal analysis of drought. In contrast to complex drought indices like the Palmer Drought Severity Index (PDSI; Palmer, 1965), SPI has the advantage of requiring only precipitation data and is not affected by geographical differences (Lana et al., 2001). Palmer’s indices, on the other hand, are water balance indices that consider water supply (precipitation), demand (evapotranspiration) and loss (runoff).
From the understanding of the science of drought in LCB based on the similarities and differences of locational attributes of temporal and spatial drought data, the following action plan is advised:
Û¢ A preliminary early warning alert may be issued in LCB for SPI values less than -1;
Û¢ A further decline in SPI value below -1.5 may serve as threshold at which a drought watch alert should be issued basin wide.
In effect, it will be safe to say there is an effective scientific tool for early drought detection and monitoring. The rest of what is needed in early drought mechanism implementation is political. This is where lessons from the current drought in the Horn of Africa are vital for LCB. The close hydro meteorological similarities should also serve as timely scientific insight for policy makers in LCB
Policy perspective and recommendations
Expert value judgment about potential risks from drought and what should be done is the role of policy makers and not scientists. Yet, it is the scientists that will help policy makers evaluate what Û÷criticalÛª drought entails by laying out the element of risk. It is apparently clear that even if the element of risk of the current drought in Somalia was made available to relevant government agencies, the financial, administrative and political structure to fully take necessary action was not in place. Moreso, the organs of the United Nations that ordinarily would have filled this gap were slow to act because the attention of the world was on Islamic insurgence operating in Somalia. From socio-policy perspective, therefore, the activities of Islamic insurgence linked with al-Qaida diverted attention away from the threat of drought.
Had attention been paid to a drought early warning mechanism and action taken in time; a fraction of the millions of dollars currently being raised to save the starving population in the Horn of Africa would have been enough to adequately coordinate resettlement away from the worst-hit areas. This would have enabled relevant authorities and agencies to start making financial and logistical arrangements to accommodate the large population of human beings and animals that will be displaced as they move south in search of water resources. Unlike Somalia, it is hoped that the activities of Boko Haram around the Lake Chad will not take attention away from the potential threat of drought in LCB.
The lesson from Somalia is that just as animals cannot survive when disconnected with their habitats; neither can humans live disconnected from the water cycle that has evolved to maintain it. The challenge to international organizations, developed countries and individual African countries is to ensure effective implementation of an early drought warning mechanism in LCB and other drought prone regions of Africa on a more sustainable basis for all users. The urgent need to move from analysis to action also underscores the need to have trained scientists proactively communicating the policy-usefulness of research findings to relevant governments and agencies.
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Okonkwo, CO A Comparison of the Spatial and Temporal Variability of Drought Indices in Somalia and Lake Chad Basin, African Journal of Environmental Science and Technology.
Churchill Okonkwo is research assistant at Beltsville Center for Climate System Observation (BCCSO), Howard University, Washington, D.C. His current research is on improving the understanding of biophysical and hydrological aspects of Land Surface Models in simulating the impacts of land-cover change on Lake Chad in the Sahel region of sub Saharan Africa. The primary tools for his research are GIS technology and variety of climate models including CWRF. He has a special interest in educating the public on the emerging issues of sustainable environment and development in Africa.