The answer to more sustainable buildings might be beneath our feet

Icelandic architect Arnhildur Pálmadóttir has successfully designed houses with only 40% of the carbon footprint of comparable conventional buildings. Her efforts to improve sustainability in the vital construction sector earned her, earlier this month, the Environment Prize of the Nordic Council. To achieve her remarkable results, she not only reuses existing materials but has also introduced a revolutionary method called "lavaforming", which is an attempt at harnassing lava from volcanic eruptions to produce a sustainable building material.

UNRIC visited Pálmadóttir's architecture studio in Reykjavík to find out more about her work. She runs the Icelandic branch of the Danish architecture and innovation company Lendager, which specializes in sustainability and circularity in construction.

Biggest emitter of CO2

Although much more focus is placed on the impact of emissions from the aviation industry, the construction sector is by far the largest emitter of greenhouse gases. It accounts for a staggering?37% of global emissions , according to the UN Environment Programme (UNEP).

Progress in this sector is imperative since cutting emissions by nine per cent annually until 2030 is needed to limit global temperature rise to 1.5 degrees Celsius. The UN Secretary-General argued in favour of this in his opening speech at COP29, the UN’s climate change conference currently being held in Baku, Azerbaijan.

“Although it varies from country to country, we can assume that half of the emissions come from the production of construction material,” Pálmadóttir says. “Earlier, the emissions that originated, for example, in China or wherever the material was produced, were not taken into account. Now, we are more honest and therefore the numbers have sky-rocketed.”?

Neglected field

According to a recent study by UNEP, attempts to reduce building emissions have focused on heating, cooling, and lighting. Considerable progress has been made in this field, but solutions have lagged in mitigating buildings’ emissions originating from the design, production, and deployment of materials such as cement, steel, and aluminium.

And this is where Pálmadóttir’s efforts come in.

Reusing material to cut emissions

She quotes several UN reports that show that if the G7 – the club of the world’s richest countries – would focus on reusing material that has already emitted carbon and change certain systems, drastically reducing construction emissions would be possible. “Right now, we are tearing down entire mountains and using coal and oil in this sector,” Pálmadóttir says.

“To reuse the material which has already emitted CO2 would make a huge difference.”

Unfortunately, at the moment, in modern urban areas, it is more common to see concrete buildings being torn down and trucks moving concrete, steel and glass to the next landfill than it is to see reusable materials being employed. This is short-sighted, according to Pálmadóttir.

We need to break up a pattern

“The Danish architecture company that I work with has successfully taken old industrial buildings and transformed them into offices and apartments. They have, for example, used the material from two old houses to build a kindergarten.”

She says many processes and systems need changing. In some cases, buildings have been condemned, and insurance companies have already paid out the indemnities.

“At this stage, I can’t jump in and say: “This can be reused“. We face many similar challenges”, she says.

“When it was decided to condemn buildings and tear them down, companies accepted their bids and showed up with their machines. We would prefer they first call us so we can reuse the material. However, that means that the deconstruction has to be organized in a different manner, which increases the costs. However, at the end of the day, I don’t think profits would decrease, although they would move around, not forgetting that this new way would foster invention.”

Life Cycle Assessment

Denmark has been a pioneer on the international stage in introducing a Life Cycle Assessment (LCA) obligation in the construction sector.

?“This means that the carbon footprint or emissions have to be calculated, and there is a certain ceiling,” Pálmadóttir explains. “Right now, this only applies to the construction of public buildings, but it is the best there is. In addition, the ceiling is supposed to be lowered and applied to more buildings. This opens the way for taxing buildings that use polluting material and compensating those who use more sustainable material.”

Science fiction?

In her native Iceland Pálmadóttir had considered ways of making construction more sustainable. Although local materials such as minerals are largely used, energy is consumed to break them down, and cement is imported. She turned her attention to lava simply because it is local and abundant, and in the 2020s, there have been several volcanic eruptions in the country.

“Nature creates and forms itself, but my question is whether we can use this and manage the flow of lava to create building material.”? She takes inspiration from history.

“Before the 1920s, using steam from volcanic activity to create energy was considered science fiction, but now it is commonly used in our country to generate electricity. So even if this looks weird, who knows….”

Using the building material of the earth

Her idea, which she calls Lavaforming, would see controlled lava flows from volcanic eruptions being used to create building material, which, according to Pálmadóttir, would be considerably more sustainable than steel and concrete.

“Lavaforming means using the building material of the Earth,” Pálmadóttir says. “The Earth’s long building process is taken over and managed. Potentially, a whole city for humans can be created in a few weeks,” Palmadóttir says. “A sustainable source of building material is created, which in addition produces the energy needed to handle and process it.”

One possible way of “Lavaforming” is to drill boreholes into the earth to reach molten lava and subsequently direct it into controlled flows and the required forms in cooling chambers, afterwards using it as building material.

Lavaforming was first exhibited in Reykjavík in 2022 but will be introduced on the international stage, appropriately in another country known for volcanic activity: Italy. Lavaforming will be Iceland’s contribution to the Venice Biennale of Architecture in May next year.