A new paper published in Science has examined how regions around the world are coping with variable and unpredictable freshwater resources caused through drought or floods, and how this affects economic output.
The analysis compares low and high income countries and their ability to cope with changes in freshwater supply and quality. At least three types of hydrologic variability cause harm: seasonal and monthly; year-to-year; and unpredictable timing and intensity of extremes. When these three combine, the situation is 'most challenging – a wicked combination of hydrology that confronts the world's poorest people', says the paper led by Professor Jim Hall, Director of the University's Environmental Change Institute. Examples include Ethiopia, where there has been 38% less economic growth than would have been expected based on average rainfall.
The challenge is that the scale of economic losses depends on factors that are difficult to isolate. While high-income countries suffer fewer economic losses than lower income ones because they are better placed to invest resources in managing risk, when their infrastructure deteriorates and extreme events become more frequent, losses can be pushed 'beyond the tolerability threshold, as seen from US impacts of hurricanes Katrina and Sandy', says the paper.
The team's analysis shows that in river basins where there has been low investment in complex hydrology, economic output is low. River basins with better hydrology are wealthier even if the investment in water management has been modest. Where the hydrology is highly variable, the paper argues that additional investment is needed to move from water-insecure to secure. It recognises, however, that the poorest countries are least able to afford to invest in improvements and the task for them is often the hardest to deliver. Critically, while investment can help move some areas towards greater water security, climate change can undermine that work.