The high resolution images from the spacecraft Artemis struck me as I am sure they did all of you. Our blue world seen from halfway to the moon is unlike any celestial body in our known universe. The photos broadcast abundant water. But, do they?
Water covers 71% of the Earth’s surface, yet only around 3% of that is freshwater and of that small percentage less is truly “fresh enough” for human consumption and agriculture.
Roughly a quarter of the Earth’s population (2.4 billion) lives with water stress. That is expected to climb to nearly a third by 2050. Water stress is far beyond what we typically label water scarcity. By water stress, we are talking about demand (usage) exceeding supply. And climate change is playing havoc on even those models.
The impacts of water stress are economic, social, environmental, agricultural and even geopolitical. When a country loses its ability to sustain its population, civil strife and the international order are threatened.
A host of terms are bantered around: Water stress, water bankruptcy. They all label the same problem. When water demand exceeds water supply, economic insecurity and food insecurity result. Food stocks are affected (agriculture accounts for 70% of the world’s freshwater usage).
In observing our planet from afar, the solution may seem obvious: Desalination. It isn’t. First some words about the process of desalination. Desalination is the removal of TDS (total dissolved salts…think calcium, magnesium, sodium) either by heating water to vapor or forcing high TDS water through membranes, a process typically referred to as reverse osmosis or RO. To do either requires energy and the production of energy is not only costly, but itself consumes freshwater (the exception being power generation by certain renewables like geothermal, wind, and solar that do not consume water).
Two sources of water are candidates for desalination: Brackish water and seawater. Brackish water is usually found underground and ranges in TDS from 1,000 to 10,000 mg/liter. Seawater’s TDS level is roughly 35,000 mg/liter. The higher the TDS level the more pressure (energy) is needed to force water through the membranes.
Brackish water desalination means the plant need not be near a coastline. That’s the good news. The bad news is that the process results in a concentrated stream of high TDS water that must be disposed of. That usually means deep well injection or returning the water to the ocean.
The US has constructed over 400 desalination plants just since 1970, with the Carlsbad, California plant being the largest (54mgd or roughly enough to supply 400,000 people). The plants are primarily sited in California, Florida, and Texas. Take Texas as an example, of its 31 aquifers, 27 are considered brackish and that’s where it employs desalination. Florida leads the nation in desalination plants (over 130 plants, mostly brackish desal but some seawater).
A problem of desalination is taste. RO water has a taste, a bit flat and oily. Take a sip of distilled water and you will see what I mean. It’s best blended with other sources to eliminate the taste factor.
For some countries, it is their only option. In Israel, 65% of the domestic water supply comes from desal. In the UAE it’s 50%. In Kuwait, its 90% and in Qatar its 99%. My March 15th Substack focused on the targeting of desalination plants in the Iran War . While a war crime under the Geneva Conventions, that hasn’t stopped Iran from hitting its neighbor’s desal plants (or hitting the electrical generating lants that power them). The US has threatened to target Iran’s plants (and apparently hit one). Desal plants have become very vulnerable targets of opportunity just as a 2010 CIA report forecasted. But with water essential to life, hopefully, cooler minds will prevail.
The serene view of Earth from 120,000 miles away shows possibilities. It’s time that the rest of us on this rock focus on the positives as well. A third of a billion people are counting on that.