The real world. No place for wishful thinking. Part 3. (Water) Pollution.

Earlier LOTRW posts revisited the two of the three simultaneous challenges to living on the real world – building resilience to Earth’s hazards, and accessing Earth’s resources (with a focus on water). Today’s post returns to the third: minimizing the pollution resulting from the first two efforts.

The enemy here is the iron reality imposed by the second law of thermodynamics: the entropy (or disorder) of the universe always increases. Building order in one sector of the universe (Florida, say, or your kitchen or desk – or even closer to home, ordering the thoughts in your mind) always requires energy, and necessarily involves polluting/degrading the environment elsewhere.

Recent studies and associated news reports have shown a spotlight on such problems as they relate to water. Take, for instance, today’s NYT report on water use in Dubai. The article opens this way: For a desert city, Dubai appears like a water wonderland. Visitors can scuba dive in the world’s deepest pool or ski inside a mega mall where penguins play in freshly made snow. A fountain — billed as the world’s largest — sprays more than 22,000 gallons of water into the air, synchronized to music from surrounding speakers.

But to maintain its opulence, the city relies on fresh water it doesn’t have. So it turns to the sea, using energy-intensive desalination technologies to help hydrate a rapidly growing metropolis.

All of this comes at a cost. Experts say Dubai’s reliance on desalination is damaging the Persian Gulf, producing a brackish waste known as brine which, along with chemicals used during desalination processing, increases salinity in the Gulf. It also raises coastal water temperatures and harms biodiversity, fisheries and coastal communities.

The article goes on to note: The Dubai Electricity and Water Authority supplies water to more than 3.6 million residents along with the city’s active daytime population of more than 4.7 million visitors, according to a 2022 sustainability report. By 2040, the utility expects these numbers to grow, increasing the demand for clean water.

The city desalinated approximately 163.6 billion gallons of water last year, according to the sustainability report. For each gallon of desalinated water produced in the Gulf, an average of a gallon and a half of brine is released into the ocean.

In Dubai, the Jebel Ali Power and Desalination Complex — the largest facility of its kind in the world — pipes water from the sea, sending it through a series of treatment phases, then to the city as drinkable water. But Jebel Ali’s 43 desalination plants are powered by fossil fuels. The U.A.E. produced more than 200 million tons of carbon in 2022, among the highest emissions per capita worldwide.

Before we start clucking our tongues stateside, the next paragraph notes: Seawater desalination has been a lifeline in the United Arab Emirates for almost 50 years, but other coastal regions, like Carlsbad, Calif., have recently adopted the technology in the face of severe drought. Florida is a national leader in desalination, and farther inland, Arizona is considering piping desalinated water from Mexico.

The links focus on urban drinking water, but recall that agriculture is by far the biggest water consumer. In this respect, a recent study by a University of Maryland researcher, Sujay Kaushal, and coauthors is causing a bit of a stir. From their abstract: …Anthropogenic activities have accelerated the processes, timescales and magnitudes of salt fluxes and altered their directionality, creating an anthropogenic salt cycle. Global salt production has increased rapidly over the past century for different salts, with approximately 300 Mt of NaCl produced per year. A salt budget for the USA suggests that salt fluxes in rivers can be within similar orders of magnitude as anthropogenic salt fluxes, and there can be substantial accumulation of salt in watersheds. Excess salt propagates along the anthropogenic salt cycle, causing freshwater salinization syndrome to extend beyond freshwater supplies and affect food and energy production, air quality, human health and infrastructure. There is a need to identify environmental limits and thresholds for salt ions and reduce salinization before planetary boundaries are exceeded, causing serious or irreversible damage across Earth systems.

Rather dry prose, but the implication is that human activity is affecting the salinity of agricultural soils globally over an area comparable to that of the United States. Soil salinity resulting from irrigation-based farming is a problem that has been with us for thousands of years (it contributed to the downfall of Mesopotamia) – but when evident on this global scale (even toning down some of the alarmist rhetoric) the problem is sobering.

Space and time limits prevent fuller description here, but entropy is also the root cause of the crumbling water infrastructure currently challenging many US urban water systems.

In all these instances, overcoming the ravages of entropy can only be accomplished locally (entropy decreases always occur at the expense of entropy increases in some larger system) and always involves the input of energy. Use of renewable energy instead of fossil fuels buys time (but only buys time; infrastructure comprising windmills and solar panels need continual maintenance and has a finite life cycle). Ultimately, the solar source of this energy will itself run its course, but that problem is hopefully a billion or so years distant.

Energy of course has its own surrogate – money. A look at that reality in the next post.

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