Hydroclimatic Extremes in the Basin of the Blue Nile
Taye, M.T. and Willems, P. 2012. Temporal variability of hydroclimatic extremes in the Blue Nile basin. Water Resources Research 48: 10.1029/2011WR011466.
In studying this important river and the region that feeds it, in the words of the two Belgian scientists who conducted the study, "the temporal variability of basin-wide rainfall extremes and river flow extremes from four gauging stations was investigated," and "on the basis of a quantile anomaly analysis method, decadal variations in extreme daily, monthly, and annual quantiles were studied, and the periods of statistical significance were identified."
Results indicated that, in regard to river flows and rainfall depths, "the 1980s had statistically significant negative anomalies in extremes in comparison with the long-term reference period of 1964-2009, while the 1960s-1970s and the 1990s-2000s had positive anomalies, although less significant." Most important of all, however, they report that "there is neither consistent increasing nor decreasing trend in rainfall and flow extremes of recent years." And, therefore, they say that "anticipated trends due to global warming could not be identified."
Once again, for another part of the world, and in spite of the oft-repeated "doom-and-gloom" prognostications of climate alarmists, the global warming experienced over the past half-century or so has not led to either extreme increases or decreases in rainfall and subsequent river flow in Africa's upper Blue Nile Basin.
Conway, D. 2005. From headwater tributaries to international river: Observing and adapting to climate variability and change in the Nile basin. Global Environmental Change 15: 99-114.
Sutcliffe, J.V. and Parks, Y.P. 1999. The Hydrology of the Nile. IAHS Special Publication 5.
Tesemma, Z.K., Mohamed, Y.A. and Steenhuis, T.S. 2010. Trends in rainfall and runoff in the Blue Nile Basin: 1964-2003. Hydrological Processes 24: 3747-3758.
Yates, D.N. and Strzepek, K.M. 1998. Modeling the Nile basin under climatic change. Journal of Hydrologic Engineering 3: 98-108.