Climate change impacts and development-based adaptation pathway to the Nile River Basin

Abstract

Nile River basin is a complex hydrological system which consists of distinct hydrological regimes at the different reaches of the river system. The runoff response of the system to the change in future climate is greatly associated to the variation in the behavior of the hydrological regimes of the river system. Developing an appropriate basin, wide adaptation strategies that promote water development in the basin requires an understanding of the sensitivity of the different hydrological regimes of the basin to climate change. From the experimental sensitivity study and existing information in the Nile basin, four distinct hydrological regimes are broadly distinguished: the water source regime, water accumulation regime (energy source regime), water-losing ecosystem regime, and the water use regime. The water source and energy source regimes are both highly sensitive to climate change. It has high stored potential energy due to the flow accumulation and elevation advantage towards the exit from the source regime. The water-losing regime consists of the extended swamps in southern Sudan and the southwestern part of Ethiopia. Building multi-year storage schemes upstream of the swamps provides flexible means of water use, maintenance of ecosystem services, and management of disruptive floods or water losses. This regime is highly vulnerable to unsustainable water abstraction than it is to climate change. If development is carefully and scientifically planned and implemented, not only water availability is improved but also the economic and physical freedom of people living around the swamps may be enhanced. Furthermore, adaptive options can be leveraged from water-saving activities through modernizing irrigation schemes and enhancing the efficiency and productivity of currently existing large-scale irrigation schemes in Sudan and Egypt. Using less water and improving allocative efficiency add up to the list of upstream adaptive measures. We conclude that there is scientific means and strong justification to adapt to climate change in the Nile basin without undermining the development needs of the riparian countries. It must, however, be underlined that without basin-wide integrated planning and management framework, the transferability of the suboptimal regime-based adaptive measures to basin-wide benefit will remain constrained. Effective basin-wide planning and management requires high-level scientific and political cooperation, institutional mechanism, and legal instruments, which currently do not exist. Integrated basin-wide climate change adaptation must be seen as an opportunity for cooperative engagement in the basin.