You can’t see any water in the air unless it is raining, or you are watching the clouds. But really? HOW CAN YOU GET WATER JUST FROM THE AIR?
If you have been following the WaterSeer blog, you already know a couple of things that make this such an interesting question. If you haven’t, just keep reading; you will want to go back and read them all later!
In the last few blogs, we discussed that the amount of clean fresh water is a lot smaller than everyone used to think, that the fresh water remaining is running out; that we are draining wells and aquifers fast than they are being replenished, that the aquifer drain is in the areas of highest population, that the water that comes through your tap is polluted with chemicals and micro-particles, that we need water for everything, that you can live for only four days without fresh water, and that the needs for clean water for health, sanitation, agriculture, farming, industry and everything else we do is rising, that global warming is making it worse, and finally, that no one has water security and independence.
We also discussed that the only untapped, unowned, and unused source of fresh water was in the air, that there is more than enough for all 7.5 Billion people to have water in abundance daily, and that it is replenished every day as fast as it was taken out.
So, we all need fresh water, it is everywhere around us, it is never-ending.. This should be easy!
Well, getting water from the air only seems easy, with apologies to Mother Nature. Everyone who has taken a cold container out of a cooler or refrigerator notices immediately that that surface becomes damp, then moist, then dripping wet, and finally creates puddles all around it. But if getting water from the air was easy, anyone could do it. It has been tried over and over stretching back to ancient pre-technical cultures. Getting water out of the air in sufficient qualities in an energy efficient scalable way is actually a wicked hard problem and the physics is brutal and inescapable.
However, it is a very worthy problem to solve. Getting the water from the air offers such a tremendous benefit and the need is so great, that it is challenge we must solve. No matter how difficult, the reward is worth the effort. If we can get water from the air, we can have water abundance, water security, and water independence for all.
Let’s get started with the physics of water vapor. Water vapor is one of the most miraculous things about water, which is an exceptionally miraculous substance. It is water in its molecular state, as a gas, in single molecules. You can not see water vapor. Water vapor is not fog, clouds, or steam, or what you see floating above boiling water or hot food; that is water droplets, which is liquid water floating in the air.
Although you cannot see water vapor you can detect it when it is in transition. For example, the bubbles that form at the bottom of a boiling pot of water are created by water vapor pressure pushing out against the surrounding water. If you watch water boiling, you can see the bubbles rise to the surface, but other than the occasional splash, the bubbles shrink and disappear as the bubbles get closer the surface. The water vapor inside the bubbles cools, the vapor pressure decreases, and the vapor condenses back into steam and water. Make sense, right? How would air get to the bottom of the boiling pot anyway?
This vapor, which can exist a very low atmospheric temperatures, is almost anywhere there is an atmosphere. You can find water vapor in the atmosphere of the sun, the extremely cold atmospheres of comets and on other stars and exoplanets. Water vapor is particularly abundant in the Earth’s atmosphere and is the key component of the warmth and the habitability of the earth's surface. In fact, water vapor is the most influential greenhouse gas, according to the American Chemical Society, accounting for 60% to 90% of global warming effect. The percentage water vapor in the air varies from 0.01% at 44 °F to 4.24% at 86 °F. That means there is a lot of water in the air (3100 cubic miles), enough to keep Niagara Falls running for over 250 years.
This water vapor is highly energetic, zipping around at tremendous speeds, and contains enormous amounts of energy. The warmer the air, the faster the water vapor molecules move (and the more energy and pressure, but let’s not get started on Bernoulli, Boyle and Maxwell). Bottom line is a typical water vapor molecule moves at 480 meters per second! That is over 1000 miles per hour! It is nearly twice as buoyant as air, and because of this buoyancy and energy it increases in density at an exponential rate as the air heats up. In other words, there is much more water vapor in warm air than in cool air.
Water vapor enters the atmosphere by evaporation from liquid water (mostly sea water) and by sublimation from ice (mostly Antarctica). During evaporation, each individual water molecule gains kinetic energy as it becomes vapor (one reason why it is so speedy). Warm air actually sucks up all the molecular water vapor it can from everything it touches (water, ice, ground, you); it is just the physics of the thing. This means that as the global warming increases there is more water in the air, and less in everything else. In practical terms, you have to keep filling up your swimming pool all summer. How much? A normal sized pool you will lose 25,000 to 50,000 gallons of water per year or about 100 gallons per day. That’s a lot of water disappearing every day that you are paying for! And the world isn’t making any more water!
OK, so we now know how water vapor gets into the air, that water vapor exists everywhere there is an atmosphere, that there is a lot of it, and that the atmosphere is sucking it up at faster rate as the world warms up. The next challenge, and the next blog, is getting it back where it belongs!
Want to know more? (www.waterseer.org) Want your own water security and Independence? (LINK: WaterSeer Reserve and WaterSeer California Video) Want to help the world get water abundance? (LINK: WaterSeer for the World Foundation) Let’s get busy!
Sources: University of Arizona Geotechnical, Rock and Water Resources Library; American Chemical Society; NOAA; Wikipedia