The number of people living in could hit nearly 700 million by the end of the century, more than triple the number today. The total area of land affected could also more than double by 2100.
Yadu Pokhrel at Michigan State University and his colleagues have modelled how the amount of water stored on land will change under varying degrees of climate change.
They studied a measure known as terrestrial water storage, which represents the sum of all water available on land, including water stored in canopies, snow, rivers, lakes and groundwater, by using hydrological models, to predict the movement and distribution of water. These models take into account variables including rainfall, temperature, humidity and wind speed.
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Under a high-emissions scenario, in which global carbon emissions peak around 2080 and decline afterwards, 688 million people, or 8 per cent of the world鈥檚 projected future population, could be in extreme to exceptional drought by 2100, compared with 200 million, or 3 per cent, in the period between 1976 to 2005. The global land area under extreme drought would also rise to 7 per cent, up from 3 per cent.
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People in the southern hemisphere will probably be disproportionately affected, particularly those living in Australia and the Amazon basin. Under such a scenario, two-thirds of land would also experience a reduction in terrestrial water storage.
鈥淭here鈥檚 a need to impose stringent climate mitigating measures, and where possible to increase water use efficiency, primarily in the agricultural sector,鈥� says Pokhrel.
鈥淚f we continue using water at the same rate as the rate that we do, and if climate change continues at the same rate, the impacts are going to be really severe,鈥� he says.
Nature Climate Change
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