Could capturing ocean vapour provide limitless water?

An almost limitless supply of fresh water exists in the form of water vapour above Earth’s oceans yet remains untapped, researchers have found.
A new study from the University of Illinois Urbana-Champaign, USA, is the first to suggest the harvesting of oceanic water vapour could augment limited supplies of fresh water in various locations around the world.
The study, led by civil and environmental engineering professor and Prairie Research Institute executive director Praveen Kumar, evaluated 14 water-stressed locations for the feasibility of a hypothetical structure capable of capturing water vapour from above the ocean and condensing it into fresh water.
Kumar, graduate student Afeefa Rahman and atmospheric sciences professor Francina Dominguez published their findings in the journal Nature Scientific Reports.

“We will need to find a way to increase the supply of fresh water as conservation and recycled water will not be sufficient to meet human needs.”
Kumar said, “Water scarcity is a global problem and hits close to home here in the US, regarding the sinking water levels in the Colorado River basin, which affects the whole Western US.
“However, in subtropical regions, like the Western US, nearby oceans are continuously evaporating water because there is enough solar radiation due to the very little cloud coverage throughout the year.
“Eventually, we will need to find a way to increase the supply of fresh water 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 scale.”
The researchers performed atmospheric and economic analyses of the placement of hypothetical offshore structures. They concluded that capturing moisture over ocean surfaces is feasible for many water-stressed regions worldwide. The estimated water yield of the proposed structures could provide fresh water for large populations in the subtropics.
Rahman said, “The climate projections show that the oceanic vapour 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.”
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.”
The researchers said this study opens the door for novel infrastructure investments that can effectively address the increasing global scarcity of fresh water.