In a world where over 50% of the population is now urbanised, cities are increasingly being called to become ‘sustainable’ and ‘resilient’. Alongside an extraordinary acceleration in urbanisation in the developing world – where megacities of 10 million or more have come into existence in an astonishingly short period of time – the idea of sustainable growth and urban resilience has sought to temper fears about this seemingly out-of-control expansion. Since at least the 1980s, the concept of sustainability in relation to architecture has come to be understood in largely technical terms: eco-technical building solutions that are focused on how a building performs, that is, how it generates and disperses the energy it needs to function.
Despite the obvious value of carbon-neutral buildings – with their energy coming from renewable sources and their materials recyclable – sustainable architecture is very rarely discussed in terms of how a building is actually made, namely the sourcing of materials and methods of construction. And this is not surprising, because in almost every case, the materials used for buildings – timber, stone, brick, iron, steel, concrete and plastic – involve subtracting from nature: timber comes from trees cut down in their prime; stones, iron and the aggregate for concrete from rocks laid down millions of years ago (ditto for the clay used for making bricks); plastics from that most unsustainable of materials, oil. Unless we return to living in structures provided by nature – the caves of our distant ancestors – can architecture and cities ever be made without destroying some part of the natural world?
Back in 1970 – as many became consumed with fear about grim urban future of environmental pollution and overpopulation – the architect Wolf Hilbertz and artist Newton Fallis first sketched out a proposal for their Autopia Ampere project – a marine city that would literally grow out of the sea at Seamount Ampere – shallow waters situated about halfway between the Madeira Islands and the tip of Portugal. The city would begin as a series of wire-mesh armatures anchored on top of a sea mountain. Once in place, the wire mesh would be connected to a supply of low-voltage direct current produced by solar panels. Over time, electrochemical reactions would draw minerals from the sea to the armatures, creating walls of calcium carbonate – a natural spiral-shaped dam that would both protect and contain a sizeable population from the otherwise hostile marine environment.
Although Autopia Ampere was never realised, Hilbertz’s visionary ‘growing’ architecture eventually led to his development (in collaboration with the coral scientist Thomas Goreau) of ‘Biorock’ in 1979 (also known as Seacrete or Seament), a substance formed by the electro-accumulation of materials dissolved in seawater. This material has found a viable use in the restoration of damaged coral reefs, with the Biorock grown to attract corals and other marine life in order to rebuild ecosystems and make them more resilient to changes in the constitution (and temperature) of sea water. In a world where coral will become one of the first casualties of climate change (and the recent upsurge in global temperates has already resulted in a huge ‘bleaching’ event on many coral reefs), Biorock is likely to become an important way of creating new marine environments out of the ruins of the old.
We may never see Hilbertz’s growing architecture evolve into habitable buildings, let alone marine cities like Autopia Ampere, but the very fact that such an architecture is possible raises questions about what ‘sustainable’ and ‘resilient’ cities might become in the future. Indeed, the idea of ‘living’ architecture is already being pushed beyond the rather superficial meaning of roof gardens or walls that sprout vegetation (from the green wall of the Caixa Forum in Madrid, installed in 2008 to Stefano Boeri’s skyscraper ‘forest’ recently completed in Milan). For example, in a 2010 TED Talk, urban designed Mitchell Joachim proposed using extruded pig cells to form buildings that are assembled using a 3D printer. He’s also argued for redesigning cities in radically new ways – whether demonstrated in his Fab Tree Hab (architecture grown on site out of trees) or buildings constructed from the rubbish generated by their residents. On an even more ambitious scale, Swedish architect Magnus Larsson has proposed growing a 6,000km long inhabitable green sandstone wall in the Sahara desert using bacterial organisms to transform the sand into a structure that will house the thousands of people displaced by desertification (another consequence of climate change) as well as providing a barrier to the Sahara expanding even more.
These projects may seem fantastical and wildly optimistic in their predictions for a radically new type of urbanism; yet, they have developed from a profound change in how humanity regards its relationship with nature. As Bruno Latour has argued, in a globalized world, there is no outside, no nature that is not already a product of an interaction between humans and the world in which they live. This realisation – and the coining of the term ‘Anthropocene’ to describe it – not only changes how we might think of our buildings and our cities; it actually demands that we do so at the most fundamental level, that is, how we source or produce materials and how we combine those materials to make buildings. Radical as this transformation is, it nevertheless has many precedents: long before Hilbertz developed his structures that grow from nature, the people of Meghalaya in northeast India began an ingenious form of natural engineering: directing the roots of Indian rubber trees to grow robust bridges across rivers that are strong enough to resist frequent flooding. With some of these bridges being as old as 500 years, they show that growing architecture has long been underway; it only remains for the rest of us to catch up.