Glaciers are not just spectacular indicators of climate change as they shrink and disappear due to global warming. They are also, for many communities, an irreplaceable source of fresh water.

During the melting season in summer, a portion of mountain glacier surface releases water that is essential to the ecosystem in the valleys below, supplying vast cities – and industries – in places like South America and India.

But this meltwater is also essential to many remote rural communities for drinking water and crop irrigation. These include those living in the Ladakh Valley, a beautiful, 470km valley sandwiched between the Greater Himalayan and Karakoram mountain ranges, and home to 300,000 people up to 4000m above sea level.

These iconic ranges have an abundance of glaciers, but large areas also fall within the monsoon rain shadow zone, which means they are extremely arid, because rain is blocked by the mountains. The Ladakh Valley is one of the most arid and coldest mountain regions in the world, with annual rain and snowfall rarely exceeding 100mm – little more than the Sahara Desert – and winter temperatures as low as -30°C.

Severe water shortages are a fundamental issue for the people who live in this cold desert. Their existence relies on the success of their crops, which can only be cultivated over a few short months of the year, often irrigated by diverted glacier meltwater. However, climate change over the past decades has meant that glaciers in the region have been shrinking, or disappearing altogether at a worrying rate, thus reducing the short growing season further.

An increasingly viable solution to this problem is the construction of ice stupas – artificial glaciers built to store winter water for use in the arid months of late spring and early summer, when meltwater is scarce. Invented in 2013 by engineer Sonam Wangchuk in Ladakh, the idea is to conserve this tower of ice as long into the year as possible so that, as it melts, it feeds the fields until the real glacial meltwaters start flowing again later in the summer.

In a collaboration with Jawaharlal Nehru University in New Delhi, our Cryosphere and Climate Change research group has been conducting a study looking at 2,200 glaciers in the wider Ladakh region. We’ve found that 86% have experienced a rise in the height of the snowline of around 300m over the past 42 years. This rate has increased to almost 10m a year over the last two decades.

Combined with drier winters, this situation has led to frequent and extended droughts, which are now threatening life-sustaining crops in rural communities. Unsurprisingly, entire villages have already been abandoned, or will be soon.

The wider issues can only be resolved through the action of governments and society as a whole, so many hopes are pinned on positive outcomes from COP26. But any solutions to augment the limited, and now declining, glacier-derived meltwater could help guarantee a sustainable future for these communities.

Locally, ice stupas offer an answer, or at least a partial way to offset the effect of shrinking glaciers in the short term. Using basic and inexpensive techniques, a conical structure of wood and steel is built and then gravity, rather than electricity, is used to bring water diverted from a nearby streams during the rainy season, and sprayed this into the air like a fountain.

The sub-zero temperatures quickly freeze the water into the conical structure, so that a mass of ice begins to grow. The end result has the same high, narrow dome-shape typical of Buddhist shrines, hence the “stupa” part of the name, which slows down subsequent melting because the surface area exposed to the sun and warm temperatures is minimised.

When the warmer, arid growing season arrives, the lower altitude streams quickly dry up and there is little water available again until June when the glaciers provide meltwater again. It is in this crucial window that the ice stupas start melting, offering an invaluable source of water for irrigation early in the growing season, extending the cropping season by a few weeks – which makes all the difference in this extreme agricultural environment.

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Constructing artificial ice reserves is not new, but in the past these were built in less efficient shapes and much higher up the mountains, making them difficult to manage. Now, these ice stupas are built next to where the water is needed most, right on the outskirts of villages, near their fields. The size and shape make them particularly efficient, inexpensive and easy to maintain, and they are able to produce millions of litres of water each year.

We’re now hoping to explore how stupas can best be used to tackle this problem. Our project is still in its infancy and more work is needed to improve some technical aspects. These include finding further sites both in the Ladakh region and other parts of the world, ways to avoid water freezing in the supply pipelines and how best to distribute water to the many villages and other users. By establishing a long-lasting collaboration with local ice stupa teams and research colleagues, we hope to provide some of the solutions.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Follow all of the Expert Voices issues and debates — and become part of the discussion — on Facebook and Twitter. The views expressed are those of the author and do not necessarily reflect the views of the publisher. This version of the article was originally published on Live Science.

Could artificial mini glaciers bring water to the driest, coldest places on Earth?

Erfan Yousefi

A series of small earthquakes northwest of Columbia, South Carolina, are caused by a man-made lake built more than 40 years ago, according to geologists.

The tiny temblors — magnitude 2.0 and less — are jangling nerves near South Carolina's Lake Monticello, according to The State newspaper, but the tremors are not unprecedented. The reservoir set off a series of minor earthquakes when it was first filled in the late 1970s. Another small swarm occurred between 1996 and 1999. Since Oct. 25, there have been seven earthquakes detected near the lake, according to the South Carolina Department of Natural Resources.

These quakes are so small that someone standing on the surface might only notice them if they were right over the epicenter and there was no rumbling traffic nearby.

"We haven't had any large earthquakes at Monticello," said Pradeep Talwani, a professor emeritus of geology at the University of South Carolina who spent his career studying earthquakes caused by man-made lakes. Going all the way back to 1977, all of the quakes in the area have been less than a magnitude 3, he said. Quakes under magnitude 3 are rarely felt.

What's happening at Lake Monticello is called "reservoir-induced seismicity." This phenomenon happens at relatively few reservoirs around the world, Talwani told Live Science. Regardless of location, the physics are always the same: A reservoir is built over rocks that contain fluid-filled fractures. When more water is loaded on top, it seeps into the fractures, causing the fluids to migrate and build up pressure. Ultimately, the pressure causes the rocks to slip and rattle the surrounding earth. This is the same reason that pumping fluids into oil wells for the purpose of fracking can cause earthquakes.

Mostly, these man-made earthquakes are small. Globally, only three reservoir-induced quakes with a magnitude of 6 or higher have ever occurred, Talwani said. (Earthquake damage can vary based on the local conditions and building materials, but magnitude 6 is typically the line at which serious damage occurs.) These damaging quakes occurred at deep reservoirs with more than 328 feet (100 meters) of water, Talwani said. In comparison, Lake Monticello is 89 feet (27 m) deep at its deepest.

It has been, however, a very well-monitored puddle. Researchers first learned about reservoir-induced seismicity in the 1960s in Denver, Colorado. Operators at a chemical weapons facility called the Rocky Mountain Arsenal drilled a deep well and began injecting waste fluid into what turned out to be highly fractured rock, triggering more than 700 earthquakes in five years, according to a 1966 article in the journal The Mountain Geologist.

Thus, scientists knew about the possibility of reservoirs triggering earthquakes by the time Monticello was constructed. Talwani and his team were already monitoring and studying small swarms at reservoirs such as Jocassee near the North Carolina-South Carolina border.

Lake Monticello was constructed in the 1970s as a water source for the nearby Virgil C. Summer Nuclear Power plant. Because scientists already knew that reservoirs could produce earthquakes, the Nuclear Regulatory Commission required careful monitoring of seismicity in the area. Talwani's research group conducted most of this monitoring, which gave them a stunningly detailed view of tiny earthquakes that wouldn't normally be picked up by U.S. Geological Survey equipment.

The lake has been the source of thousands of tiny quakes over the years, most far too subtle to be felt. The initial swarm of earthquakes after the reservoir filled wasn't surprising. But the quakes in the 1990s, 20 years after Lake Monticello was constructed, were a little more mysterious. Thanks to their detailed seismic monitoring, Talwani and his colleagues were able to figure out what had happened. Over time, they found, water from the lake had dissolved mineral "caps" that had been sealing off fractures in the rock. With these new fractures opened, water was able to move into them, again building up pressure and causing the rocks to slip.

Something similar is probably happening at Monticello now to cause the new earthquakes, Talwani said. However, it's impossible to say because the fine-grain seismic monitoring system is no longer in place. That means researchers can see only the largest quakes, not the miniscule ones that help them localize the origin of the seismicity.

"Now we have no idea what is going on, because we just have one [seismic] station in that area," Talwani said.

Researchers at the University of South Carolina may soon deploy more seismometers in the area, said Scott Howard, a state geologist at the South Carolina Department of Natural Resources. The quakes are likely to peter out or continue at the current levels of magnitude, Howard told Live Science.

Strange earthquakes in South Carolina traced to man-made lake

Milad Azami

In the 1930s, a Swiss astronomer named Fritz Zwicky noticed that galaxies in a distant cluster were orbiting one another much faster than they should have been given the amount of visible mass they had. He proposed than an unseen substance, which he called dark matter, might be tugging gravitationally on these galaxies.

Since then, researchers have confirmed that this mysterious material can be found throughout the cosmos, and that it is six times more abundant than the normal matter that makes up ordinary things like stars and people. Yet despite seeing dark matter throughout the universe, scientists are mostly still scratching their heads over it. Here are the 11 biggest unanswered questions about dark matter.

First and perhaps most perplexingly, researchers remain unsure about what exactly dark matter is. Originally, some scientists conjectured that the missing mass in the universe was made up of small faint stars and black holes, though detailed observations have not turned up nearly enough such objects to account for dark matter's influence, as physicist Don Lincoln of the U.S. Department of Energy's Fermilab previously wrote for Live Science. The current leading contender for dark matter's mantle is a hypothetical particle called a Weakly Interacting Massive Particle, or WIMP, which would behave sort of like a neutron except would be between 10 and 100 times heavier than a proton, as Lincoln wrote. Yet, this conjecture has only led to more questions ­ — for instance…

If dark matter is made from WIMPs, they should be all around us, invisible and barely detectable. So why haven't we found any yet? While they wouldn't interact with ordinary matter very much, there is always some slight chance that a dark-matter particle could hit a normal particle like a proton or electron as it travels through space. So, researchers have built experiment after experiment to study huge numbers of ordinary particles deep underground, where they are shielded from interfering radiation that could mimic a dark-matter-particle collision. The problem? After decades of searching, not one of these detectors has made a credible discovery. Earlier this year, the Chinese PandaX experiment reported the latest WIMP nondetection. It seems likely that dark-matter particles are much smaller than WIMPs, or lack the properties that would make them easy to study, physicist Hai-Bo Yu of the University of California, Riverside, told Live Science at the time.

Ordinary matter is made up of everyday particles like protons and electrons, as well as a whole zoo of more exotic particles like neutrinos, muons and pions. So, some researchers have wondered if dark matter, which makes up 85 percent of the matter in the universe, might also be just as complicated. "There is no good reason to assume that all the dark matter in the universe is built out of one type of particle," physicist Andrey Katz of Harvard University said to Space.com, Live Science's sister site. Dark protons could combine with dark electrons to form dark atoms, producing configurations as diverse and interesting as those found in the visible world, Katz said. While such proposals have increasingly been imagined in physics labs, figuring out a way to confirm or deny them has so far eluded scientists. [Strange Quarks and Muons, Oh My! Nature's Tiniest Particles Dissected]

Along with additional particles of dark matter, there is the possibility that dark matter experiences forces analogous to those felt by regular matter. Some researchers have searched for "dark photons," which would be like the photons exchanged between normal particles that give rise to the electromagnetic force, except they would be felt only by dark matter particles. Physicists in Italy are gearing up to smash a beam of electrons and their antiparticles, known as positrons, into a diamond, as Live Science previously reported. If dark photons do exist, the electron-positron pairs could annihilate and produce one of the strange force-carrying particles, potentially opening a brand-new sector of the universe.

As physicists increasingly fall out of love with WIMPs, other dark-matter particles are starting to gain favor. One of the leading replacements is a hypothetical particle known as an axion, which would be extremely light, perhaps as little as 10 raised to the 31st power less massive than a proton. Axions are now being searched for in a few experiments. Recent computer simulations have raised the possibility that these axions could form star-like objects, which might produce detectable radiation that would be quite similar to mysterious phenomena known as fast-radio bursts, as Live Science previously reported.

Astronomers discovered dark matter through its gravitational interactions with ordinary matter, suggesting that this is its main way of making its presence known in the universe. But when trying to understand the true nature of dark matter, researchers have remarkably little to go on. According to some theories, dark-matter particles should be their own antiparticles, meaning that two dark-matter particles would annihilate with one another when they meet. The Alpha Magnetic Spectrometer (AMS) experiment on the International Space Station has been searching for the telltale signs of this annihilation since 2011and has already detected hundreds of thousands of events. Scientists still aren't sure if these are coming from dark matter, and the signal has yet to help them pin down exactly what dark matter is.

Because it so massively outweighs ordinary matter, dark matter is often said to be the controlling force that organizes large structures such as galaxies and galactic clusters. So, it was strange when, earlier this year, astronomers announced that they had found a galaxy named NGC 1052-DF2 that seemed to contain hardly any dark matter at all. "Dark matter is apparently not a requirement for forming a galaxy," Pieter van Dokkum of Yale University told Space.com at the time. However, over the summer, a separate team posted an analysis suggesting that van Dokkum's team had mismeasured the distance to the galaxy, meaning its visible matter was much dimmer and lighter than the first findings and that more of its mass was in dark matter than was previously suggested.

A long-standing mystery in particle physics are the puzzling results of a European experiment known as DAMA/LIBRA. This detector — located in an underground mine below the Gran Sasso mountain in Italy — has been searching for a periodic oscillation in dark matter particles. This oscillation should arise as the Earth moves in its orbit around the sun while flying through the galactic stream of dark matter surrounding our solar system, sometimes called the dark matter wind. Since 1997, DAMA/LIBRA has claimed to see exactly this signal, though no other experiment has seen anything like this.  

A signal from the beginning of time has led some physicists to suggest that dark matter might have an electrical charge. Radiation with a wavelength of 21 centimeters was emitted by stars in the universe's infancy, just 180 million years after the Big Bang. It was then absorbed by cold hydrogen that was around at the same time. When this radiation was detected in February of this year, its signature suggested that the hydrogen was much colder than scientists had predicted. Astrophysicist Julian Muñoz of Harvard University hypothesized that dark matter with an electrical charge could have drawn heat away from the all-pervasive hydrogen, sort of like ice cubes floating in lemonade, as he told Live Science at the time. But the conjecture has yet to be confirmed.

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Could artificial mini glaciers bring water to the driest, coldest places on Earth?

Strange earthquakes in South Carolina traced to man-made lake

The 11 biggest unanswered questions about dark matter