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Lakes Are Shrinking | Earth Wise

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A study by the University of Colorado Boulder has found that more than half of the world’s largest lakes have shrunk over the last three decades.  This is a very big problem because about one-quarter of the Earth’s population lives in the basin of a drying lake.  People depend on lakes for drinking water and irrigation and lakes are central to the survival of local ecosystems as well as migrating birds.  Lakes cover only about 3% of the planet, but they hold nearly 90% of the liquid surface freshwater.

The study used satellite observations from 1992 to 2020 to estimate the area and water levels of nearly 2,000 freshwater bodies.  These account for 96% of Earth’s total natural lake storage and 83% of that in man-made reservoirs.  About 53% of the world’s lakes have clearly shrunk, while only 22% have gained water.  The study estimates that about 160 trillion gallons of water has been lost over the 28-year period.  That’s about 17 times the maximum capacity of Lake Mead, the largest reservoir in the United States.

Many of the world’s most significant lakes have been shrinking. The dramatic declines in Lake Mead have been headline news for years.  The Caspian Sea, which is the world’s largest inland body of water – has long been declining.

The main causes of the decline in natural lakes are climate change and human consumption.  Reservoirs face an additional major problem of sediment buildup which reduces their storage capacity and diminishes their benefits of water supply, flood control, and hydropower.

Lake loss is a big problem.

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More than half of the world’s largest lakes are drying up

Photo, posted April 10, 2018, courtesy of Ninara via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Solar Panels On Canals | Earth Wise

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There has been growing interest in installing solar panels on top of reservoirs to make use of the available space to make electricity and reduce evaporation.  There has been far less interest in installing solar on canals and aqueducts.  But that is changing and a new project in California is part of that change.

A study by the University of California, Merced estimates that 63 billion gallons of water would be saved by covering California’s 4,000 miles of canals with solar panels.  All that installed solar would generate a significant amount of electricity.

The idea is going to be tested in the Turlock Irrigation District in Central California with Project Nexus, which is the installation of solar panels over 1.8 miles of canals that are between 20 and 110 feet wide.  The panels will sit between 5 and 15 feet off the ground.  UC Merced researchers will study impacts ranging from evaporation to water quality and use the results to make recommendations with respect to wider use of the technology.

California isn’t the first place to put solar on a canal.  India pioneered it on one of the largest irrigation projects in the world.  The Sardar Sarovar dam and canal project brings water to hundreds of thousands of villages in the dry, arid region of India’s Gujarat State.

Meanwhile, the Gila River Indian Community in Arizona received funding from the Bipartisan Infrastructure Law to install solar panels on their canals in an effort to save water and reduce stress on the struggling Colorado River.

The world of water infrastructure does not embrace change easily but covering canals with solar panels is an idea whose time may have come.

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Solar panels on water canals seem like a no-brainer. So why aren’t they widespread?

Photo, posted December 11, 2005, courtesy of Dave Parker via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Keeping The Colorado River Flowing | Earth Wise

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The Colorado River supplies drinking water to 40 million Americans in seven states as well as to many Mexicans and provides irrigation to 5.5 million acres of farmland.  Electricity generated by dams on the Colorado powers millions of homes and businesses in the West.

A combination of drought, population growth, and climate change has reduced the river’s flows by a third in recent years compared with historical averages.  Further reductions could trigger a water and power catastrophe across the Western states.

California, Arizona, and Nevada all get water from Lake Mead, the reservoir formed by the Colorado at Hoover Dam.  The Interior Department determines how much water each of these three states receives.  The other states that use Colorado River water get it directly from the river and its tributaries.  Last summer, water levels in Lake Mead and Lake Powell fell enough that officials feared that the hydroelectric turbines at the Colorado’s dams would soon cease functioning.

The three states have recently struck an agreement with the federal government to take less water from the Colorado.  The reductions amount to about 13% of the total water use in the lower Colorado.  The government will pay about $1.2 billion to irrigation districts, cities, and Native American tribes for temporarily using less water.  The states have also agreed to make additional cuts to generate the total reductions needed to prevent the collapse of the river.

The agreement runs only through the end of 2026.  At that point, all seven states that rely on the river – which includes Colorado, New Mexico, Utah, and Wyoming – may well be facing a deeper reckoning.  The forces driving the decline of the Colorado are not going away.

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A Breakthrough Deal to Keep the Colorado River From Going Dry, for Now

Photo, posted June 16, 2017, courtesy Karen and Brad Emerson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A Miracle Tree | Earth Wise

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The world needs to be fed without destroying the environment.   We need to grow more trees to store more carbon on earth and reduce the amount in the atmosphere.  But meanwhile, we decimate rainforests to produce palm oil and grow soybeans.

A startup company in California called Terviva thinks they have a solution.  It’s called pongamia, which is an ordinary looking tropical tree.  It produces beans packed with protein and oil, much like soybeans.  However, it has the potential to produce much more nutrition per acre than soybeans and it is hardy enough to grow on pretty much any kind of land without the use of pesticides, fertilizers, or irrigation.  In short, it is a miracle crop for a hot and hungry planet that is running out of fertile farmland and fresh water.

Pongamia is not a new or rare tree.  It is common in India but grows all over the world.  It is often planted as an ornamental here in the U.S.

The initial idea for making use of the hardy tree was to use its oil as a biofuel.  The seeds of pongamia are known to have a bitter taste and disagreeable odor, which is why the seeds or oil were never used for human or animal feed.  However, Terviva has developed a way to de-bitter pongamia oil.  Once this is done, it becomes a golden-colored substitute for olive oil. It also has enormous potential as a protein for plant-based milks and meats, since it contains all nine essential amino acids.

Terviva has raised more than $100 million to further develop pongamia and is now partnering with Danone, a $25 billion multinational food company, to develop pongamia as a climate-friendly, climate-resilient, non-GMO alternative to soy and palm oil.

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This super-tree could help feed the world and fight climate change

Photo, posted December 15, 2015, courtesy of Lauren Gutierrez via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Tepary Beans | Earth Wise

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Tepary beans are an ancient crop native to the northern part of Mexico and the southwestern part of the U.S..  They have been grown in those places by native peoples since pre-Columbian times.  They are still grown in Native American reservations in Arizona’s Sonoran Desert.  One can purchase them from some small farms in that region. 

What sets tepary beans apart from other beans is that they are among the most drought- and heat-tolerant legume crops in the world.  They can be grown without irrigation under conditions that are not viable for other crops.  They can be consumed by people like many other kinds of beans, and they can also provide forage for livestock with better nutrition content than many other plants.  They seem to be a very attractive option for a crop in the changing climate.  What is lacking, at present, is large supplies of tepary seeds to be planted.

Researchers at Texas A&M have been funded to bring tepary beans into modern cropping systems and diets.  The goal is to develop tepary bean cultivars with high biomass and yield that are still well-suited to drought and heat conditions.  Getting the beans to the point of widespread commercialization will take several years.  The end result should be of interest to pulse growers, seed industries, and food companies across the U.S.

Tepary beans are higher in fiber and protein than most other beans.  They come in several different colors, each of which has unique flavor and texture characteristics.  The white ones have a naturally sweet flavor.   The brown beans are slightly nutty in flavor and are similar to pinto beans.  If the Texas program is successful, we may all be eating tepary beans some day.

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Tepary Beans Offer Producers A Low-Input, Climate-Resilient Legume Alternative

Photo, posted August 25, 2017, courtesy of Katja Schulz via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Scourge Of Salt | Earth Wise

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Rising seas are increasing saltwater intrusion on land and rising temperatures are causing greater evaporation.   The result is mounting levels of salt in waters and in soils.

Rising sea levels cause salty ocean water to push further into river deltas.  There is already a surge in saltiness across all inhabited continents.   Seawater works its way further upstream when dams hold back water.  Pumps that remove fresh water from underground sources for irrigation and drinking supplies add to the problem.  In dry regions, irrigation systems delivering water to crops increasingly bring salt onto fields.

People add to the problem by pouring saline drainage water from mines into rivers and by using salt to de-ice roads in the winter.

A modeling study pinpointed hotspots for climate change-induced salinization in numerous locations including the U.S. Southwest, wide areas of Australia, Mexico, South Africa, Brazil, central India, northern China, and more.

Some ecosystems are adapted to saline environments but major alterations in the balance between saline and fresh water is creating growing problems for ecosystems, lake fisheries, crop growing, and even human health.

The damage caused by salt is likely to be so severe that salinization will become a major cause of environmental refugees when the land they live on can no longer sustain them. 

Salt will be a growing threat to the world’s food supplies, especially where farmers depend on artificial irrigation.  About a third of the world’s food is grown in irrigated fields, and a fifth of those fields are deemed to already be salt-contaminated.  Ultimately, only a halt to climate change will be capable of combatting the scourge of salt.

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Salt Scourge: The Dual Threat of Warming and Rising Salinity

Photo, posted June 3, 2017, courtesy of Jason Jacobs via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Global Assessment Of Groundwater Wells | Earth Wise

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Water is a fundamental need for every human being on the planet.  Each person requires more than five gallons of clean and safe water a day for drinking, cooking, and keeping clean.

Groundwater wells remain one of the primary sources of drinking water.  In fact, more than half of the world’s population gets its drinking water from groundwater wells.  Groundwater wells also sustain more than 40% of irrigated agriculture.

Researchers from UC Santa Barbara have recently compiled the most comprehensive assessment of groundwater wells to date.  Their research, which was recently published in the journal Science, spanned 40 countries, which collectively account for more than 50% of all groundwater pumping. 

According to the survey’s findings, many wells are at risk of running dry – up to one in five wells, to be exact.  The researchers compared the depths of water tables against well depths. They found that 6% to 20% of the wells in the study were at risk of running dry if water levels continue to decline by just a few meters.

In many areas where groundwater levels are declining, the research team found that new wells are not being drilled deeper to keep pace with the falling water table. As a result, newer wells are just as vulnerable as older wells should groundwater levels continue to decline.  

The researchers hope to expand on this study to include data from China, Iran, and Pakistan, three major users of groundwater from which the researchers could not obtain records.  The researchers also plan to investigate how quickly water tables are dropping and where the trend is accelerating.   

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The largest assessment of global groundwater wells finds many are at risk of drying up

Photo, posted January 20, 2018, courtesy of François Molle via Water Alternatives Photos on Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Self-Watering Soil | Earth Wise

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Researchers at the University of Texas at Austin have created a new type of soil that can pull water from the air and distribute it to plants.  Such soil has the potential to expand the map of farmable land to previously inhospitable places as well as to reduce water use in agriculture in an era of growing droughts.

The team’s atmospheric water irrigation system makes use of super-moisture-absorbent gels to capture water from the air.  When they are heated to a high enough temperature, the gels release the water, making it available to plants.

The gels in the soil pull water out of the air during cooler, more humid periods at night and when the sun heats the soil during the day, the water-containing gels release their contents into the soil.

Each gram of soil can extract about 3-4 grams of water.  Depending on the specific crop, somewhere between a couple of ounces and 2 pounds of the soil can provide enough water to irrigate a square yard of farmland.

Experiments on the soil found that it retains water better than the sandy soils found in dry areas and needs much less water to grow plants.

In one experiment, radish plants germinated in the soil all survived a 14-day period without any irrigation beyond the initial watering when they were planted.  Radish plants in ordinary sandy soil irrigated for the first four days of the experiments lasted no more than two days further without watering.

The Austin group has been developing gel-polymer materials that work like super-sponges for two years.  These materials extract large amounts of water from the ambient air, clean it, and release it when heated with solar energy.

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Self-Watering Soil Could Transform Farming

Photo, posted October 21, 2020, courtesy of the U.S. Department of Agriculture via Flickr. USDA Media by Lance Cheung.

Earth Wise is a production of WAMC Northeast Public Radio.

Glaciers And Water Supply

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The world has roughly 150,000 glaciers covering about 200,000 square miles of the earth’s surface.  Over the last 40 years they’ve lost the equivalent of a layer of ice 70 feet thick.  Most of them are getting shorter as well.  Some have shrunk to nothing; many smaller glaciers in places like the Rockies and the Andes have disappeared entirely.

Glaciers represent the snows of centuries, compressed over time to form flowing rivers of ice.  They always change over time, accumulating snow in winter and losing ice to melting in summer.  But in recent times, the warming climate has allowed the melting to outpace the accumulation.

Much of the discussion about the retreating glaciers relates to sea level rise, catastrophic floods, debris flow, and the effects on rivers and ecosystems.

But in some places, the biggest impact of the loss of glaciers is on the supply of water for people and agriculture.  In Kazakhstan, Almaty, the country’s largest city depends on glacier-fed rivers for drinking water for its 2 million people and for irrigation water for crops.  All across the Tibetan Plateau and the Himalayan and Karakmoram mountain ranges, hundreds of millions of people rely on glacier-fed rivers for their water supplies. 

A melting glacier can at first increase stream flow but eventually reaches a tipping point and meltwater begins to taper.  In the short term, the melting glaciers may provide increased amounts of water coming down from the mountains, but eventually the flow in the rivers will begin to decline and populations will face a crisis.

It will be essential for people in many places to carefully plan for their future water needs in a changing world.

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Glaciers Are Retreating. Millions Rely on Their Water.

Photo, posted September 16, 2011, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Collecting Clean Water From The Air

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Clean water is an essential requirement for human life and there are many places where it is a scarce commodity.   In the world’s deserts, getting water to people requires feats of engineering and irrigation that can be cumbersome and expensive.

Researchers at Ohio State University have produced a couple of new studies that explore options for gathering water from fog and condensation that are based on principles of biomimicry:  copying strategies already in use by plants and animals.

The researchers looked at how cactus, beetles and desert grasses all collect water condensed from nighttime fog, gathering droplets from the air and filtering them to roots or reservoirs.

The cactus they studied collects water on its barbed tips before guiding droplets down conical spines to the base of the plant. They learned that conical shapes gather more water than do cylindrical shapes.  This is because of a physics phenomenon called the Laplace pressure gradient.

The beetles they studied collect drops of water on waxy, water-repellent bumps on their backs.  The water then slides towards the beetle’s mouth on the flat surface between the bumps.  Based on this, the researchers experimented with structures that include multiple hydrophilic cones with spaces in between where water droplets can coalesce.

From grasses, they learned that grooved surfaces move water more quickly than ungrooved surfaces – in fact, about twice as much.

The work so far has been on a laboratory-level, but the researchers envision scaling up to structures in the desert that can gather water from fog or condensation and supplement public systems or wells either on a house-by-house basis or on a community-wide basis.  Copying cacti, beetles and grasses could supply clean water to people in the desert.

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Collecting clean water from air, inspired by desert life

Photo, posted February 7, 2010, courtesy of Remko van Dokkum via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And Barley

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The impacts of increased carbon dioxide and the changing climate are often complicated and, it turns out, not always negative.  In some areas of the world, people can actually benefit from increased CO2 and climate change. Barley, the most important feed crop for beef production in Alberta, Canada, as well as the province’s beef industry itself actually stand to gain from the changes that are most assuredly not a good thing for much of the world.

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The Great Salt Lake Is Shrinking

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Utah’s Great Salt Lake is the largest salt water lake in the Western Hemisphere and is the largest body of water in the United States after the five Great Lakes.  When the pioneers first arrived in the area back in the middle of the 19th century, the lake spread across about 1,600 square miles.   Now, the lake covers an area of only about 1,050 square miles, a reduction of about 35%.

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