March 26 (UPI) -- New models suggests water scarcity is not just a local problem, but one with global consequences.
Not only can local scarcity trigger wide-ranging economic impacts, but shifts in global demand can alter the pressure on river basins around the world.
The models, described Friday in the journal Nature Communications, suggest the ripple effects of water scarcity can exacerbate the effects of global warming.
"We're finding that water scarcity dynamics are more complicated than traditionally acknowledged," lead study author Flannery Dolan said in a press release.
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"Changing water supply due to climate change is only part of the story. Regional water scarcity is also driven by changes in global water demands that are often hard to anticipate," said Dolan, a graduate student at Tufts University.
To build their models, scientists accounted for all the inputs that can alter hydrologic conditions in 235 major river basins, including climate change, land management, global trade and population growth.
Simulations showed local water scarcity can influence trade and consumption patterns across a diversity of industries, including agriculture, energy, transportation and manufacturing.
The models also showed the socioeconomic impacts of water scarcity depend on where the water is coming from -- rainfall, snowmelt and ground water -- and where its going, whether to farms, power plants or sinks and showers in the city.
When groundwater supply in the lower Colorado River basin is low and population growth is high, the economic impacts of water scarcity are especially negative, but under some hydrological conditions, high population growth is beneficial.
Conversely, in the Indus Basin in Pakistan, simulations showed global land use policies intended to curb carbon emissions can lead to added pressure on the region's groundwater supply.
"What is happening elsewhere in the world through differences in regional choices related to energy transitions, how land is being managed, as well as different regional water demands and adaptive choices, can shape relative advantages and disadvantages of a region's water intensive economic activities," said co-author Patrick Reed, professor of civil and environmental engineering at Cornell University.
The economic ripple effects of water scarcity are usually negative, but in some water-rich places, like Venezuela, scarcity elsewhere can offer an economic advantage.
According to the models, the different water-related feedback loops produced by human activities can amplify the impacts of climate change on hydrological conditions.
Though the models suggest river basins around the world are vulnerable to unsustainable consumption patterns, the complexity of factors influencing any one basin's hydrological conditions make a one-size-fits-all solution an impossibility.
"It is noteworthy that the lower Colorado River basin has some of the most uncertain and widely divergent economic outcomes of water scarcity of the basins analyzed in this study," Reed said.
"This implies that assumed differences in regional, national and global human activities as well as the intensity of climate change can dramatically amplify the uncertainty in the basin's outcomes," he said.
