Water resources and climate change

This century human-induced global warming will result in huge change to the Earth’s climate system. The most immediate impact will be on the hydrological cycle, as increased energy drives a more intensive process of evaporation and precipitation.

The regional impacts of this change will vary, but are anticipated to include in different places more intensive but shorter precipitation events and increased drought risk. By 2020, in Africa, for example, from 75-250 million people will be subject to increased water stress as a result of climate change. In particular, there are major dangers associated with changes to river systems including the Niger in West Africa.

These changes will not only be direct on human populations, reducing access to water and increasing risk of inundation, but also indirect and longer-term as ecosystems shift in space and in species composition, and agro-ecological boundaries accommodate new growing seasons. Immediate impacts may include reduced access to water and food, as well as increased hazards as exposure to disease vectors change (e.g. Anopheles mosquitoes carrying the Malaria parasite). In a country like Uganda, the potential impacts are immense. It is estimated that a rise in temperature of 2 Celsius this century will wipe out the production of coffee on which some 5 million people depend, with potentially severe direct impacts on poverty. In Ethiopia, rising temperatures will increase the spread of Malaria-carrying mosquitoes from lowland to some highland areas where there are far higher population concentrations, including in Tigray and Amhara regions.

In parts of Africa and South Asia, inter-annual variability in rainfall is already an immediate challenge for the poorest households. These future changes are likely to increase their risk burden which is why an increasing sense of urgency surrounds investment planning in water. This includes a focus on improving adaptive capacity and building climate resilience into economic and social planning decisions at all levels.

The sections below provide a brief snapshot of three key issues: the anticipated development impacts of climate change, including implications for adaptation to changes in water availability and access; the wider challenge of interpreting and using climate data at different scales in order to plan the development of water resources more effectively; and the larger institutional issue of how global water and climate communities can more meaningfully be brought together.

Development impacts

Poorer households already struggle to access clean water and safe sanitation facilities. Major changes to the hydrological cycle will increase risks associated with inadequate access, including greater food insecurity, disease burden and low availability of livelihood assets (in particular land, labour and finance). More...

Complex science

Although there is a strong consensus that global warming is leading to major climate change, a major challenge remains in transferring the science into practical decision making environments at national level and below, particularly (though not exclusively) in developing country contexts. More...

The Water-Climate nexus

There is a strong convergence of water, climate, energy and food security issues at the current time. In part this is driven by the impact of climate change science on development policy and the aid environment, and, specifically, the push to mainstream responses to climate change across development sectors. More...