The Ingenious Ice Towers of the Himalayas
17. Sometimes the Best Tech for Climate Change Adaptation Is Simple (8 min read)
If you have been to any North American city where it snows a lot, the picture above might be familiar. Snow plows and clearing vehicles accumulate snow from streets and parking lots and pile them onto a small hill. The “snow hill” can range anywhere from a few feet high to the gigantic dirt covered snow mountains like the one in Boston a few years ago:
The urban planning wisdom is to deposit snow removed from the roads to wherever you can find unused space. By the time spring and summer roll in, the heat would melt it to water, which would go down the stormwater drainage system.
While a pile of fresh snow can provide infinite recreational opportunities, a dirty pile of snow covered by soot from automobiles and industry can be an eyesore. Such was the monstrosity in Boston, and the situation was met with varying degrees of amusement and annoyance from the public and the city government. There were some legitimate worries: Small piles of snow by the street melt in Spring. But the larger it gets, the harder it is to melt. And the Boston pile was becoming so big that some worried if it would ever fully melt.
But melt it did, and it was announced with much fanfare (and disappointment to some who had grown affectionate to its presence).
This post is not about Boston, though. It’s all about the date this pile melted on - July 14th - when summer was already months in. Winter was firmly in the rear-view mirror.
Why does it take so long to melt? And why am I writing about a pile of snow by the road?
Welcome to this week’s Climatonomics.
(My apologies for the delay with this week’s issue - I spent a bit too much time playing in the fresh mountain snow ;-))
The Ice Stupas
Here is another pile of snow, but in extremely different conditions. And of course, much cleaner. While the Boston pile was an inconvenience resulting from some uninspired snow management in a big city with, let’s just say, creative layout of roads (hey, drive in Boston and you’ll complain too), this pile… known as the ice stupa, results from a much more deliberate and serious enterprise.
This snow mountain is man made and is in the beautiful Indian state of Ladakh. Ladakh lies in the Himalayas, where elevation is at least 9000 feet above sea level. Unlike several mountain regions in the world, we characterize Ladakh as a high desert, with little rain and snowfall to feed to communities that live there. Ladakh has a unique culture and the vast area has several villages, some as high as 13,000 feet. Thousands of people here live in one of the dryest and coldest mountain regions in the world, which gets barely more rain than the Sahara desert, but temperatures drop to negative 30 Celsius1.
Life here is hard: the sheer remoteness of this place from major cities, not to mention geopolitical and military skirmishes between India and neighboring China, ensures that urban infrastructure development here is non-existent.
And people here desperately need water. Climate change has made the region even drier than it has been, and the situation has got worse enough that parts of the region run out of water in the summer. With these unique sets of circumstances, the people and the many Buddhist monks that call this region home have been extremely self-sufficient. And they realized the water crisis also requires them to roll out their own solution, which has to be simple, yet effective. Easy to maintain, yet cheap to build.
Enter the Ice Stupas. Stupas are tall Buddhist shrines, which are popular in the region. The Ice stupa is much the same, except that they make it of snow. Snow, much like the Boston pile, that melts slowly well into the summer.
Except that here, the snow melt provides life-sustaining water for communities nearby. Farmers grow crops from this water, instead of relying on unpredictable rains, which are growing scarcer with climate change. The ice stupa is essentially a water reservoir, but importantly, without the complexities - and the expense - of a traditional building.
How do the Ice Stupas Work?
When I first read about these, I was intrigued by how austere the stupas looked.
The lack of complexity and cost is something we do not appreciate in urban areas. But repeatedly, we have seen that the communities bearing the brunt of climate change impacts are rural, remote and often lacking the financial and technological resources to maintain sophisticated technology to deal with climate adaptation.
Now, the average temperature in Ladakh is below freezing for nearly 8 months in a year, with summers seeing an average high of just 10 degree C.
The Ice Stupa designers saw the frigid 8 months as an opportunity. If water can be frozen as ice, they can store it for most of the year until next summer with minimal risk of melting. When water flows naturally from glacier melts, a pipeline transports this water to the location where the villagers want an ice stupa. Typically, this is on the outskirts of the village, near farms, where irrigation is a necessity for food security. The pipeline then turns 90 degrees facing the sky and shoots out the water high as a fountain, aided by gravity and water pressure (so it needs no electricity). The freezing weather ensures that the water freezes as it comes down and deposits around. Gradually, the ice builds up as long as the water fountain keeps operating and temperatures are freezing.
The result is majestic:
While most stupas melt completely in summer, the holy grail of ice stupa engineering is making it permanent: If the stupa becomes big enough during the melt season, then it’s less likely to melt fully. If the stupa still has some ice left before the next melt season starts, it will theoretically keep growing every year and become a perennial water source, much like any natural glacier. A few stupas have indeed got to this point over several years, but its rare.
Why are ice stupas so effective when natural glaciers melt faster? The basic physics is that of surface area vs. volume. Ideally, we want more volume for lesser surface area, so that there is less heat transfer to the interior, where the bulk of the ice is stored. Ice is a great insulator, as the Inuit and native peoples of the arctic have showed for millennia with igloos.
The stupa follows the same concept, and the conical shape was chosen because it can provide one of the best surface-area-to-volume ratios: While there are many more mathematically optimal shapes, such as a sphere and octagon, these are hard to build2. But the cone is simple, and naturally builds itself as water freezes around a fountain.
Challenges and “Sciencing” the Stupas
The Ice stupa has transformed how people in Ladakh use water. But it’s not without its shortcomings: As temperatures keep rising, the ice stupas are not lasting as long as they used to. I read reports that people in Ladakh are building fewer stupas now than before, because it is too warm to be viable. In short, climate change has outpaced what we can do with simple technology.
While intuitive engineering based on basic physics can show as a viable proof of concept, making the technology work reliably well needs far more scientific sophistication. The challenge now is to optimize the design to extend stupa life by even a few weeks, which can make a massive difference for communities.
There are several practical challenges in building pipelines in harsh, remote terrain and to ensure the fountain works exactly as intended. Water can freeze inside the pipeline (a pain to fix). Determining the exact location of the stupa so that it melts slowly is also important. Also, not all water is converted to ice, resulting in wastage.
Academic researchers have been making inroads into this problem. An exciting approach presented this year shows an ice stupa can be far more effective than we know today. To quote the authors:
… tested an automated system that controlled how much water was sprayed, when, and for how long, based on models and weather data. Preliminary results from drone measurements found the automated system dispensed 13% of the amount of water used by the manual fountain system to create ice stupas that delivered the same or more meltwater. The automated systems also did not require winter maintenance.
So.. just around one-tenth of the water can still be used to create stupas where pipelines can work reliably year round. And this is just the first iteration of this technology, and much like others, I expect this to get considerably better when scientific resources are devoted to it.
Local Solution, Global Adoption?
Despite the recent setbacks, one thing is certain: Ice stupas provide a solution to a problem where few others have. Another notable point is that this tech was entirely envisioned, built and demonstrated by the Ladakhi people themselves, particularly Sonam Wangchuk, who was, incidentally, immortalized in the internationally acclaimed Indian movie 3 idiots3.
This illustrates another crucial, yet overlooked, point in climate change adaptation: Local problems often need local solutions. While academics and scientific labs can help, the people at ground zero have a far superior understanding of the environment and problem to make a first attempt at the solution. Climate change is geography-specific, and so should be the solutions. Empowering the local population is the best shot we have at adapting to the changing planet, and Ladakh has led by example.
And now, their simple but ingenious tech is getting attention from another major high-desert region on the other side of the planet: The Nilus project aims to replicate the success of the ice stupas in Ladakh in the dry regions of the Andes, and initial testing is already underway.
It’s stories like these that give me hope for the future - low tech, cheap and rapidly deployed. Last week’s issue focused on something similar, and I will be on the lookout for more such emerging tech from the ground zero of climate change.
In the 21st century, simplicity is often undervalued, but that attitude has to change if we are adapt to climate change. What do you think?
And hey, thanks for reading! Wish you all a very happy, successful and prosperous 2023!
Did you like this edition of Climatonomics? Subscribe to get more awesome content every week.
Know someone who might find this useful? Climatonomics is free so go ahead and share!
Ladakh is also on the shadow-side of the world’s highest mountains - the Himalayan range - which blocks most rain-bearing clouds from entering the region. Result: The region entirely depends on snow melt during the summer, but rising temperatures mean that a lot of the snowmelt is lost as runoff sooner and not providing a consistent, summer-round supply as it used to.
For the more mathematically inclined, here is a paper studying the energy transfer mechanism in ice stupas and predicting how long they can stay without fully melting.
While movie recommendations are not under the purview of Climatonomics, I will make a strong exception here. The movie’s idea of academics being only worthy when a thirst for knowledge is paired with social good is an urgent message in today’s world, and resonated in several nations with hyper-competitive academic pressure.
Fascinating! How much water does a stupa provide a community and is it transported with another pipeline?