When I first sat down to speak with Icelandic architect Arnhildur Pálmadóttir, I was a bit skeptical. Since 2018, his company, SAP, has been researching how to harness molten lava from Iceland’s myriad volcanoes and use it as a natural building material.
The concept sounded wildly eccentric, but the more she talked, the more I realized something. If humans can drill for oil 20,000 feet below the ocean, why can’t we make the same kind of effort to mine other material that springs from the earth?
The architect‘s exploration has now resulted in a project called Lavaforming, which recently featured in an exhibition in Reykjavík. The idea came as a radical response to the climate crisis.
Currently, construction and building materials are responsible for 11% of annual global CO2 emissions. This has led to a growing movement among architects and developers to use materials that have a lower carbon footprint than concrete and steel, and come from local sources: think adobe for much of the Africa, bamboo for China and even agave waste for Mexico.
In Iceland, lava seemed such an obvious contender that Pálmadóttir was genuinely surprised no one had thought of it before. “We don’t have a lot of natural resources, we have rock and lava fields,” she says.
Now the architect has unveiled three ideas for how the lava would be mined: digging trenches for the lava to flow when a volcano erupts, drilling into the magma (before it erupts and turns in lava) and 3D print bricks with molten lava. The proposal focuses on Iceland, but it could apply to the other 1,500 active volcanoes scattered around the world.
Here’s how it might work. The first scenario is based on a natural eruption, which in Iceland occurs on average every five years. (The last took place in March 2021, 25 miles southwest of the capital Reykjavík, but as National geographic reported, it may have triggered decades of frequent volcanic eruptions.)
So the next time a volcano erupted, slow-flowing lava would flow through a network of pre-dug trenches. These could be used to redirect lava and protect nearby critical infrastructure. The trenches could also be used to form the foundations of a new city since the lava cools into solid rock. And if you were to dig the ground around the trenches, now filled with solidified lava, those trenches could become walls.
In this scenario, the architects would rely on prediction models that scientists are currently working on, such as weather forecasts, but for volcanoes. Designed to predict where and when the next eruption will occur, these models could be linked to a design model, “so that we can predict where to place the city,” says Arnar Skarphéðinsson, architect at SAP (and son of Pálmadóttir).
When there are no volcanic eruptions on the horizon, architects want to rely on ongoing scientific research into geothermal energy. Iceland is divided by a fault that divides the country from east to west. At the bottom of this fault, pockets of fiery magma transfer heat to the rocky mantle of the Earth above: if properly harnessed, this so-called geothermal heat could be used to generate huge amounts of electricity.
Such research is already underway near the Krafla volcano in northern Iceland. If architects could use similar equipment, they could drill even further and hit pockets of magma that they can extract. The material could then be molded into bricks or manipulated into a 3D printing material.
And yes, it could be the plot of a disaster movie, but as Pálmadóttir notes, the Massachusetts Institute of Technology is already printing with molten glass. Why wouldn’t it work with molten lava?
Despite all their crazy ideas, the architects remain somewhat realistic. “We think it’s a good idea, but we realize it might not happen in our lifetime,” says Skarphéðinsson. For him, the radical nature of the project illustrates how devastating the building materials crisis is and how desperate architects are to find a more sustainable solution.
But there is something else too. In 2012, Iceland held a constitutional referendum. One question asked whether citizens wanted natural resources on the island that are not already private to be declared national property. The answer was yes, but Skarphéðinsson claims that “nothing has been done” since then.
“If we had this constitution and we could build a lava city, the whole city would be state owned and we think that’s a big step in the climate crisis,” he says, because citizens would have more control over the country’s natural resources, which could help promote climate equity. “We don’t want Elon Musk to own the lava.”