irrigation

Bananas and climate change

April 17, 2025 By EarthWise Leave a Comment

Bananas are one of the most widely produced fruits globally, with more than 100 million tons grown every year. They are a key export crop worth approximately $11 billion annually. Bananas are also a staple food in many tropical countries, playing a vital role in both the economies of these nations and in global food security.

The Cavendish variety of banana dominates commercial exports, accounting for nearly 47% of global production. However, the Cavendish banana is highly susceptible to diseases like Panama disease, prompting ongoing efforts to develop disease-resistant alternatives. The spread of these diseases is exacerbated by climate change, which alters growing conditions and weakens banana plants. Additionally, climate change poses further threats to the banana industry by impacting crop yields and distribution patterns.

In fact, a new study led by researchers from the University of Exeter in the U.K. has found that by 2080, rising temperatures will make growing bananas for export economically unsustainable in many regions of Latin America and the Caribbean. Colombia and Costa Rica will be among the countries most negatively impacted as they are expected to become too hot for optimal banana cultivation.

The study, which was recently published in the journal Nature Food, found that 60% of the regions currently producing bananas around the world will struggle to grow the fruit unless there are urgent interventions to tackle climate change. The researchers propose several adaptation strategies, including expanding irrigation systems, developing heat- and drought-resistant banana varieties, and helping banana producers manage climate-related risks.

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Climate change threatens future of banana export industry

Photo, posted June 26, 2024, courtesy of JJ Musgrove via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Saving the Great Salt Lake

January 27, 2025 By EarthWise Leave a Comment

For many years, scientists have warned that the Great Salt Lake in Utah is headed toward a catastrophic decline. While the size of the Great Salt Lake fluctuates naturally with seasonal and long-term weather patterns, the lake has been experiencing significant and steady declines for decades. In fact, the Great Salt Lake has lost more than 15 billion cubic yards of water over the past three decades, and it’s getting shallower at the rate of four inches a year.

This reduction is primarily due to excessive water diversions from rivers and streams that feed into the lake for agricultural, industrial, and municipal use. These diversions, combined with prolonged drought and rising temperatures due to climate change, have significantly reduced the lake’s water level.

According to a new study led by researchers from Oregon State University, 62% of the river water bound for the Great Salt Lake is diverted for human use, with agricultural activities responsible for nearly three-quarters of that percentage. The analysis, which was recently published in the journal Environmental Challenges, found that reducing irrigation is necessary to save the lake.

In order to stabilize and begin refilling the lake, the research team proposes cutting human water consumption in the Great Salt Lake’s watershed by 35%. The researchers emphasize that farmers and ranchers facing income losses from using less water would require taxpayer-funded compensation.

The Great Salt Lake is a biodiversity hotspot, sustaining more than 10 million migratory birds. The lake also directly supports 9,000 jobs and fuels $2.5 billion in economic activity annually.

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Reducing irrigation for livestock feed crops is needed to save Great Salt Lake, study argues

Photo, posted January 14, 2024, courtesy of Olaf Zerbock via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Rivers are drying up

November 4, 2024 By EarthWise Leave a Comment

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

Strawberries and climate change

August 12, 2024 By EarthWise Leave a Comment

The demand for strawberries continues to climb around the world. According to data from World Population Review, China remains the global leader in strawberry production, a spot it’s held since 1994. Last year, China produced 3.3 million tons of strawberries, followed by the United States at 1.05 million tons, Egypt at 597,000 tons, and Mexico at 557,000 tons.

While strawberries are grown coast to coast in the U.S., California and Florida are the top two strawberry-producing states due to their favorable climate conditions. In fact, California produces more than 90% of the domestic strawberry crop. But Florida plays a key role in domestic strawberry production as well by growing the majority of the winter crop.

A new study by researchers from the University of Waterloo in Canada has examined the effect of climate change on California’s strawberry crop. According to the research team, strawberries could be fewer and more expensive because of the higher temperatures caused by climate change. The report, which was recently published in the journal Sustainability, found that a 3° Fahrenheit rise in temperature could reduce strawberry yields by up to 40%.

According to the researchers, the impact of climate change on strawberry production could be mitigated by implementing certain sustainable farming practices. These include optimizing irrigation to ensure adequate water supply during heat waves and using shading plants and shade structures to mitigate heat stress.

Understanding how rising temperatures affect crop yields should encourage farmers and governments to develop sustainable agriculture responses to global warming.

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Influence of Regional Temperature Anomalies on Strawberry Yield: A Study Using Multivariate Copula Analysis

Strawberry Production by Country 2024

Researchers predict fewer, pricier strawberries as temperatures warm

Photo, posted June 3, 2007, courtesy of David Slack via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The East Coast is sinking

March 11, 2024 By EarthWise Leave a Comment

Most of the world’s largest cities are located in coastal regions and coastal regions are on the front lines of the climate crisis. Human populations continue to migrate towards low-elevation coastal areas at the same time that sea level rise is accelerating. Coastal communities worldwide are increasingly vulnerable to the dangers of flooding and erosion. With these hazards occupying a great deal of attention, there has been less attention paid to the dangers of land subsidence.

A recent study by researchers at Virginia Tech and the US Geological Survey using satellite data shows that parts of America’s east coast are sinking, and the culprit is the withdrawal of too much water from the aquifers beneath these coastal areas.

A series of overlapping aquifers extends all the way from New Jersey to Florida along the coast, providing a reliable source of water for drinking, irrigation, and industrial uses. Even though these areas get regular rainfall, the deeper aquifers can take hundreds or even thousands of years to refill once water is pumped out. Once water is removed, soils can compress and collapse, causing the land surface to sink.

Cities that were built on drained marshland or on fill soil are especially vulnerable to compaction.

Seal level rise is slow, but it is insidious and continuous. Add land subsidence to the mix and effects multiply. Places like Boston, New York, Washington DC, Roanoke, Savannah, Jacksonville, and Miami, among others, all are increasingly vulnerable to these coastal hazards. The combined effects of sea level rise and subsidence may even triple the prospects for flooding areas over the next few decades.

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As Aquifers Are Depleted, Areas Along The East Coast Of The US Are Sinking

Photo, posted August 7, 2015, courtesy of Tracy Robillard / NRCS Oregon via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Groundwater and climate change

February 22, 2024 By EarthWise Leave a Comment

Groundwater is the vast reserve of water beneath Earth’s surface. It’s an essential resource for humans, plants, animals, and other living organisms. According to the United States Geological Survey, about 30% of all readily available freshwater in the world is groundwater. In areas lacking sufficient surface water supply from rivers and reservoirs, groundwater is critical for meeting the region’s drinking water and food production needs.

But climate change, as well as global population growth, is stressing groundwater resources. As precipitation becomes less reliable due to climate change, surface water bodies can drop too low to provide the needed water. As a result, people turn to groundwater. Depletion of groundwater is already a significant problem, and over-pumping will only increase further as climate change makes traditional sources of water less reliable.

According to a new study led by researchers from the University of Michigan, farmers in India have adapted to warming temperatures by intensifying the withdrawal of groundwater used for irrigation. The study, which was published in the journal Science Advances, found that the rate of groundwater loss could triple by 2080 if this trend continues, further threatening India’s food and water security.

India is the second-largest global producer of common cereal grains such as rice and wheat, and recently passed China as the world’s most populous nation. Without interventions to conserve groundwater, the research team finds that warming temperatures will likely amplify India’s groundwater depletion problem, further threatening the country’s food and water security.

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Groundwater depletion rates in India could triple in coming decades as climate warms, study shows

Where is Earth’s Water?

Photo, posted August 2, 2013, courtesy of Rajarshi MITRA via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Groundwater loss

December 21, 2023 By EarthWise Leave a Comment

Groundwater is the water found underground in the cracks and spaces in soil, sand, and rock. It is held in aquifers and bubbles up naturally into springs, streams, and rivers, but also is pumped out for use by people. Groundwater provides almost half the drinking water in the U.S. and is a main source of water for agriculture.

The world’s supply of groundwater is steadily declining. The combination of climate change and human population growth is increasingly diminishing groundwater.

A study by the Desert Research Institute published in the journal Nature Communications has mapped the global permanent loss of aquifer storage capacity for the first time. Computer modeling with advanced machine learning techniques has provided a detailed picture of the world’s groundwater situation.

The study found that global aquifer storage capacity is disappearing at a rate of 10 miles a year, about the size of 7,000 Great Pyramids of Giza. The loss of groundwater storage is permanent, forever reducing the amount of water that can be captured and stored because the pumping of groundwater can cause the ground surface above to sink, collapsing the space where water can be stored.

About 75% of this subsidence is occurring over cropland and urban regions. The United States, China, and Iran account for most of the global groundwater storage loss but many other places in the Middle East and Asia are experiencing significant groundwater withdrawal as well.

Most regions of the world do not have monitoring programs for groundwater pumping. The study underscores the need to better understand this issue on a global scale and take appropriate action before it is too late.

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Scientists Map Loss of Groundwater Storage Around the World

Photo, posted August 7, 2015, courtesy of NRCS Oregon via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Floating Sea Farms | Earth Wise

October 18, 2023 By EarthWise Leave a Comment

Researchers at the University of South Australia have designed a self-sustaining solar-driven system that turns seawater into fresh water and grows crops without any involvement. In theory, such a system could help address the growing problems of freshwater shortages and inadequate food supplies as the world’s population continues to increase.

The system can be described as a vertical floating sea farm. It is made up of two chambers: an upper layer similar to a greenhouse and a lower chamber for water harvesting.

Clean water is supplied by an array of solar evaporators that soak up seawater, trap the salts in the evaporator body and, heated by the sun, release clean water vapor into the air which is then condensed on belts that transfer the water into the upper plant growth chamber.

The researchers tested the system by growing broccoli, lettuce and bok choi on seawater surfaces without maintenance or additional clean water irrigation. The system was powered entirely by solar light.

The design is only a proof-of-concept at this point. The next step is to scale it up using an array of individual devices to increase plant production.

The futuristic potential for such technology would be huge farm biodomes floating on the ocean. The UN estimates that by 2050, nearly 2.5 billion people are likely to experience water shortages while the global supply of water for irrigation is expected to decline by 19%. Nearly 98% of the world’s water is in the oceans. Harnessing the sea and the sun to address growing global shortages could be the way to go.

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Floating sea farms: a solution to feed the world and ensure freshwater by 2050

Photo, posted February 11, 2015, courtesy of Ed Dunens via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Lakes Are Shrinking | Earth Wise

September 11, 2023 By EarthWise Leave a Comment

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

August 25, 2023 By EarthWise Leave a Comment

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

July 5, 2023 By EarthWise Leave a Comment

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

September 27, 2022 By EarthWise Leave a Comment

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

September 2, 2022 By EarthWise Leave a Comment

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

June 10, 2022 By EarthWise Leave a Comment

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

May 19, 2021 By EarthWise Leave a Comment

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

December 9, 2020 By EarthWise Leave a Comment

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

March 25, 2019 By EarthWise Leave a Comment

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

February 6, 2019 By EarthWise Leave a Comment

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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