Threat of Climate Change to the Nile-Lake Victoria
In addition, along its 3,000 km course through arid northern Sudan and southern Egypt, the Nile loses a huge amount of water to evaporation. This makes water supply extremely sensitive to temperature and precipitation changes.
Climate warming models provide diverging pictures of future river flows in the Nile from a 30% increase to a 78% decrease. In addition, saltwater intrusion into coastal freshwater resources (including aquifers) is likely to increase as a result of sea-level rise due to climate warming and would further reduce the availability of freshwater in the delta region.
Climate change may make Egypt drier and warmer, intensifying its dependency on irrigation. In light of the high and growing human demands for water and water-intensive agriculture on the banks of the Nile, reduced water flows under climate change would be catastrophic.
Climate change will also have a significant impact on fisheries, affecting both the productivity of fish populations and how they are distributed. Small changes in temperature can dramatically alter water levels, mixing regimes and fish productivity.
This may result in increased fish productivity in the short term, but not indefinitely. Higher temperatures in Lake Victoria can result in slackened winds, less intense mixing, and changes in the nutrient dynamics which would affect fisheries productivity and completely alter the trophic structures of fish communities.
Sporadic upsurges of the 'oxycline' threshold in the water column, below which waters are starved of oxygen, have risen to depths as shallow as 10 m in Lake Victoria, and have already been associated with fish kills. Reduced fish production could affect food availability, aggravate poverty and possibly exacerbate political instability in the region.
Lastly, the Nile basin traverses the largest number of countries of any basin in Africa; changes in the timing and availability of water under climate change may lead to tension, insecurity and management problems.