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Rivers are drying up

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According to a new U.N. report, the world’s rivers had their driest year in at least three decades.  Record heat and droughts in many places contributed to low levels of water in many of the world’s rivers.

The world faces problems of either too much or too little water. The warming climate has fueled both powerful storms with heavy rainfall and intense droughts around the globe. 

Last year was the hottest year on record, and it’s a record that is unlikely to last long.  The Mississippi River and Amazon River basins were at all-time lows.  Major rivers with headwaters in the Himalayas – the Ganges, Brahmaputra, and Mekong Rivers – were all unusually dry.

According to the World Meteorological Organizations State of Global Water Resources Report, nearly half of the nearly 1,000 rivers tracked around the world had below-normal levels of water.  Only 17% had above-average levels.  Over the past 32 years, on average only a quarter of the rivers monitored had below-normal water levels and last-year’s 45% was the largest ever.

Last year’s severe heat shrank glaciers that are a crucial source of meltwater that feeds rivers.  Glaciers lost more ice last year than they have in at least 50 years.

More than half of the world’s population lives within a couple of miles of a body of fresh water.  The places with the highest population densities around the world are almost all near large rivers.  Rivers provide freshwater for irrigation, consumption, and transportation and are an important source of energy. Historically, they have played an important role in the development of human society.  The shrinking of rivers is a big deal.

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World’s Rivers Are Driest They Have Been in Decades

Photo, posted August 22, 2023, courtesy of Radek Kucharski via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

AI’s Environmental Footprint

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Artificial intelligence is everywhere these days.  Some say it is the biggest development since the discovery of fire.  There is a lot of hype regarding AI, and it will be a while before the hype is sorted out from the reality.  But one thing that is certain is that AI is resource-intensive and has a large environmental footprint.

AI use directly produces carbon emissions from its consumption of non-renewable electricity and is also responsible for the consumption of billions of gallons of fresh water.

Various forms of AI run on many types of devices, but the kind of AI we hear about the most – such as ChatGPT – requires specialized computer equipment that runs in large cloud data centers.  There are roughly 10,000 such centers worldwide and more are under construction.  Estimates are that electricity consumption from data centers will double between 2022 and 2026 to a total of 1,000 terawatts, roughly as much electricity as all of Japan uses.

These estimates include all data center activities, not just AI.  Most operators of data centers don’t reveal what percentage of their energy use comes from AI.  One exception is Google, which says machine learning accounts for about 15% of its data center energy use.

Data centers also consume a great deal of water to cool delicate electronics.  In 2022, Google’s data centers consumed about 5 billion gallons of fresh water.

AI has the potential to improve the efficiency of systems, improve climate models, and perhaps help develop new ways to help reduce humanity’s environmental footprint.  But at the moment, it represents an increasing burden on the environment that cannot just be ignored.

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As Use of A.I. Soars, So Does the Energy and Water It Requires

Photo, posted January 23, 2023, courtesy of Aileen Devlin / Jefferson Lab via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Harvesting Fresh Water From Ocean Air | Earth Wise

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Roughly three-quarters of the world population has access to a safely managed water source.  That means that one-in-four people do not have access to safe drinking water.  Even in the wealthy United States, persistent drought in the west is creating problems in places like Phoenix, Arizona.

Water is plentiful on Earth but more than 99% of it is unusable by humans and many other living things because it is saline, frozen, or inaccessible.  Only about 0.3% of our fresh water is found in the surface water of lakes, rivers, and swamps.

There is an almost limitless supply of fresh water in the form of water vapor above the oceans, but this source is untapped.  Researchers at the University of Illinois have been evaluating the feasibility of a hypothetical structure capable of capturing water vapor from above the ocean and condensing it into fresh water.

Existing ways to obtain fresh water like wastewater recycling, cloud seeding, and desalination have met only limited success and present various problems with regard to cost, environmental impact, and scalability.

The researchers have proposed hypothetical large offshore structures measuring 700 feet by 300 feet to capture water vapor that is continually evaporating from the ocean in subtropical regions.   Their modeling concluded that such structures could provide fresh water for large population centers in the subtropics.  Furthermore, climate projections show that the amount of water vapor over the oceans will only increase over time, providing even more fresh water supply.

This is only a theoretical study at this point, but the researchers believe it opens the door for novel infrastructure investments that could address global water scarcity.

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Researchers propose new structures to harvest untapped source of fresh water

Photo, posted June 28, 2009, courtesy of Nicolas Raymond via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Solar-Powered Desalination | Earth Wise

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About 1% of the world’s population is dependent on desalinated water to meet daily needs, but water scarcity is a growing problem that experts believe will affect 14% of the world’s population within the next five years.

Desalination takes much more energy than, for example, transporting fresh water over large distances.  In general, desalination costs are much higher than those associated with fresh water, but beyond costs, freshwater is simply not always available.

Researchers at MIT and Shanghai Jiao Tong University in China have developed a completely passive solar-powered desalination system that could provide more than 1.5 gallons of fresh drinking water per hour for every square meter of solar collecting area.   Such a system could provide an efficient, low-cost water source for coastal areas that are off the grid.

The system uses multiple layers of flat solar evaporators and condensers topped with transparent aerogel insulation.  The key to its efficiency is the way it uses each of its multiple stages to desalinate water.  At each stage, heat released by the previous stage is harnessed instead of wasted.  The proof-of-concept device, which was tested on an MIT building rooftop, produced more than twice as much water as the record amount produced by any previous passive solar-powered desalination system.

The researchers plan further experiments aimed at optimizing the choice of materials and configurations and to test the system under realistic conditions.  The hope is to have a technology that can play a role in alleviating water scarcity in parts of the world where electricity is scarce, but seawater and sunlight are abundant.

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Simple, solar-powered water desalination

Photo courtesy of MIT/researchers.

Earth Wise is a production of WAMC Northeast Public Radio.

A Water Superpower

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In 2008, Israel was on the verge of catastrophe.  A decade-long drought in the Fertile Crescent of the Middle East was scorching the area.  Israel’s largest source of fresh water, the Sea of Galilee, had dropped to within inches of the so-called black line at which point irreversible salt infiltration would flood the lake and ruin it forever.

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