According to researchers, there is a virtually infinite supply of fresh water in the form of water vapor above the oceans of the Earth. In order to address the world’s limited fresh water supply, a new study from the University of Illinois Urbana-Champaign is the first to advocate investing in new infrastructure that can collect oceanic water vapor.
The study, led by civil and environmental engineering professor and executive director of Prairie Research Institute Praveen Kumar, assessed the viability of a hypothetical structure capable of capturing water vapor from above the ocean and condensing it into fresh water while doing so in a way that will remain feasible in the face of ongoing climate change at 14 water-stressed locations around the world.
Kumar, graduate student Afeefa Rahman, and atmospheric sciences professor Francina Dominguez published their findings in the journal Nature Scientific Reports.
“Water scarcity is a global problem and hits close to home here in the U.S. regarding the sinking water levels in the Colorado River basin, which affects the whole Western U.S.,” Kumar said. “However, in subtropical regions, like the Western U.S., nearby oceans are continuously evaporating water because there is enough solar radiation due to the very little cloud coverage throughout the year.”
The researchers noted that previous desalination, cloud seeding, and wastewater recycling methods have had only patchy success. Desalination facilities are used in several regions of the world, but their production of brine and wastewater containing heavy metals poses sustainability problems. As a result, California has rejected plans to build more desalination plants.
The climate projections show that the oceanic vapor flux will only increase over time, providing even more fresh water supply. So, the idea we are proposing will be feasible under climate change. This provides a much-needed and effective approach for adaptation to climate change, particularly to vulnerable populations living in arid and semi-arid regions of the world.
Afeefa Rahman
“Eventually, we will need to find a way to increase the supply of freshwater as conservation and recycled water from existing sources, albeit essential, will not be sufficient to meet human needs. We think our newly proposed method can do that at large scales,” Kumar said.
The researchers conducted atmospheric and economic assessments to determine the best location for fictitious offshore constructions that were 210 meters wide and 100 meters tall.
The researchers’ calculations led them to the conclusion that many water-stressed places throughout the world could benefit from trapping moisture over ocean surfaces. Large subtropical population centers could receive fresh water from the predicted water yield of the proposed structures.
Wet areas will become more wet, and dry areas will become drier, according to one of the most reliable predictions of climate change.
“The current regions experiencing water scarcity will likely be even drier in the future, exacerbating the problem,” Dominguez said. “And unfortunately, people continue moving to water-limited areas, like the Southwestern U.S.”
However, the new ocean vapor-harvesting technique benefits from this forecast of increasingly drier circumstances.
“The climate projections show that the oceanic vapor flux will only increase over time, providing even more fresh water supply,” Rahman said. “So, the idea we are proposing will be feasible under climate change. This provides a much needed and effective approach for adaptation to climate change, particularly to vulnerable populations living in arid and semi-arid regions of the world.”
The fact that this suggested solution mimics the natural water cycle is one of its more elegant aspects, according to the researchers.
“The difference is that we can guide where the evaporated water from the ocean goes,” Dominguez said. “When Praveen approached me with this idea, we both wondered why nobody had thought about it before because it seemed like such an obvious solution. But it hasn’t been done before, and I think it is because researchers are so focused on land-based solutions but our study shows other options do, in fact, exist.”
According to the researchers, this study opens the way for cutting-edge infrastructure investments that can successfully manage the growing global freshwater shortage.
The University of Illinois Urbana-Champaign, the Lovell Professorship in the department of civil and environmental engineering, The University Scholar Program, and the National Science Foundation supported this research.
