Protecting the Global Commons of Atmospheric Water Content to Meet Humanity's Drinking Water Needs

Image of humidity in the air

Understanding Water Supply

The Target 6.1 of the Sustainable Development Goal 6 “Clean Water and Sanitation” focuses on our need for drinking water: “Universal and equitable access to safe and affordable drinking water for all.” Talyan et al. (2025) find that reaching this Target by 2030 requires a sixfold increase of the current rate of progress. Two billion people are still without reliable access to clean drinking water.

Traditional Water Supply

Traditional water infrastructure for the distribution of drinking water based on extensive pipe systems requires large investments and comes with high maintenance costs. In many areas, existing infrastructure is outdated and creates high losses of water within the networks. Many sources exploited for drinking water are polluted and the tap water provided is of insufficient quality. Many sources are also not sustainably used and are projected to be depleted in the near future. Tackling all these problems makes progress towards Target 6.1 slow and expensive.

Global Water Cycle

In the global water cycle, the atmosphere is a reservoir with very high flows of water in and out. The average residence time of water in the atmosphere is very short, on the order of eight to nine days. The annual flow of water in form of water vapor into the atmosphere due to evapotranspiration is on the order of 505,000 km³, i.e., 0.505 El (exaliters). This corresponds to a flow of 16 Gl/s (gigaliters per second) into and out of the atmosphere. In order to relate this to human needs, this equates on a global scale to 2 l/s/person or roughly 170,000 l/d/person. Even if humanity would extract roughly 20 liters per person per day from the atmosphere, this would be on the order of 0.01% of the total flux into and out of the atmosphere. Energy usage to extract this amount of water from the atmosphere would be on the order of 0.5 GW under optimum conditions (needing 0.25 kWh/l and assuming 24-hour operations) and maybe 1 GW to account for large areas with low humidity and lower temperatures. This amount of energy is extremely small compared to the energy use, e.g., for data centers.

The stock of water in the atmosphere is on the order of 12,000 km³. Taking out 20 l/day per person would amount to roughly 1% of this stock. Considering the very short residence time, the tapping into the stock would have minimal impact on the dynamics in the atmosphere. Considering that the on-going climate change is expected to increase the atmospheric water contents, this reduction has the potential to reduce negative impacts of climate change on atmospheric dynamics.

Sustainability of Atmospheric water Generation

The above shows that utilizing the water vapor in the atmosphere to meet the global demand of high quality drinking water is a sustainable solution. It also is a solution with minimal impact on the environment. If most of the energy required for the extraction of water from air is provided by instantaneous or low-latency solar energy, then this extraction would result in close to zero emissions of carbon dioxide or other Greenhouse gases.

Utilizing rivers and lakes as drinking water resources has several significant challenges. In many areas rivers and lakes are polluted and using the water requires advanced cleaning process with high energy demands. Where reservoirs are built to ensure water supply during droughts, impacts on freshwater ecosystems are often extreme.

In many areas, groundwater is already an overexploited resource. Aquifers, which in general have much longer residence times for water than the atmosphere (in most cases hundreds to thousands of years), can easily be depleted. Lowering the groundwater level in shallow aquifers can have a severe impact on the ecosystems which are not adapted to the lower groundwater levels. Extracting groundwater from aquifers can also result in large subsidence of the surface impacting the built environment significantly. In coastal areas, groundwater extraction can amplify sea level rise.  

Impact of Atmospheric Water Generation

Atmospheric Water Generation

The air to water technology has evolved rapidly over the last decade. There is now a wide range of atmospheric water generators (AWDs) that can be used to provide access to clean potable water where it is needed. Commercially available AWGs come in size from 10 l/day for small homes to 5,000 l/day for larger demands, and water factories producing 1,000,000 l/day for larger communities are also available.   

The prospect of meeting humanity’s needs for clean drinking water for all by utilizing the atmospheric water content comes with the danger of triggering efforts to privatize this global commons. There are already efforts to give the right to utilize water in the air to companies and take it away from communities of individuals. A major effort is needed to permanently protect the atmosphere and the water contained in the atmosphere as one of the global commons. This needs to be paired with the human right of having access to sufficient drinking water, and the right to source this drinking water out of the atmosphere.