Growing Freshwater Scarcity From Disruptive Climate Change Leads to Aerial Water Harvesting Invention

In 2023 I wrote, “Drylands cover more than 46% of the global land area where three billion people live. Nearly 30% of humans today have no indoor drinking water. The risk of desertification is growing.” The Middle East and North Africa (MENA) is home to four of the Earth’s five most water-stressed countries. They are Qatar, Bahrain, Kuwait and Lebanon. MENA countries have devised a drought index to help monitor the severity of water-stressed areas. Among the innovations MENA countries are developing include new varieties of drought-tolerant crops and best practices in water conservation. In addition, however, inventors in MENA countries are finding ways to harvest freshwater from bone-dry air.

Numerous techniques and inventions help harvest water from the air even in the desert. Many use the heat of the Sun interacting with different types of hydrophilic materials to distill water vapour from the air.

In 2017, the water harvester seen above was developed to convert energy from sunlight which was passed through a porous metal material that per kilogram in weight can harvest up to 2.8 litres of freshwater every 12 hours even in air with humidity levels as low as  20%. How dry is that? At 20% body moisture gets sucked out of you leading to dangerous dehydration.

The water harvester invention in the above picture was developed in 2022 in Saudi Arabia. It combines solar panels with an underlying hydrogel that condenses water from the air.

Water harvesters can be as simple as a terra cotta clay pot that can serve multiple purposes, drawing water from dry air or purifying water poured into it using the heat generated within the confined space and the hydrophilic properties of zinc-plated metal sheets to yield up to 5 litres of liquid per day.

To those mentioned above and many other water harvesting technologies, we can now add Janus crystals.

What are they? Panče Naumov, Professor of Chemistry at Jilin University in Abu Dhabi heads a team of researchers who have developed a water harvester using three different organic compounds that form Janus crystals. The compounds have all been tested to determine their interactions with airborne water and those chosen to form the crystal combine both hydrophilic and hydrophobic properties. The former attracts water while the latter repels it. The combined material forms a porous matrix of crystals that are highly efficient harvesters of water and don’t require any energy input like other water harvesters. Naumov notes that the crystals efficiently capture and collect freshwater from the Earth’s atmosphere. They are “self-sensing, and efficient surface-active harvesters which, when used at a larger scale, can help us combat water scarcity at a societal level.”

The crystals are tiny. A microlitre water droplet is larger than the width of one. Constructing a water harvester from them requires positioning them to optimally take advantage of the crystal’s attraction and repulsion characteristics.

Today over 3.8 billion live in areas where people experience freshwater scarcity at least once each month. The problem is expected to grow to encompass 5 billion by 2050 as climate change exacerbates water stress over a larger area of the planet. Even the United States will see freshwater scarcity as an increasing problem, particularly in the U.S. Southwest, Midwest and Southeast.

Freshwater scarcity contributes to illnesses linked to inadequate water supplies including cholera, typhoid, polio, hepatitis A, diarrhea and more. The threat to food security is potent as well as climate change contributes to droughts and other extreme weather conditions. The cascading effects will only grow without action on climate change. Without addressing that elephant in the room the technological fixes described here will provide only a modicum of relief.