There is some evidence that such thinking is beginning to take hold.
Global use of cement is forecast to expand by 1.0% per year to 4.1 billion metric tons in 2023, and that will have substantial environmental impacts. Producing one metric ton of cement requires three metric tons of construction sand (a non-renewable resource that’s in increasingly short supply), generates a lot of CO2 and can use as much as 305 liters of water. Under growing pressure from governments, clients and end-users, builders are innovating to reduce the negative environmental impact of their buildings. Cement technicians are working hard on developing more environmentally sustainable forms of concrete such as one that is claimed to absorb CO2 as it hardens.
Meanwhile, reports seem to indicate that structural timber is making a strong comeback with a big assist from technology to create engineered wood or “mass timber”. For example, pressure-bonding layers of timber together into CLT (Cross Laminated Timber) produces fire-resistant wooden slabs and sections that can match and even beat the performance of concrete and steel to make big structures. The world’s tallest wooden building is now the Mjøstårnet in Norway, standing at 85.4 meters. That building is slated to be overtaken by the proposed 80 stories of the River Beech Tower in Chicago. Environmentally aware proponents of mass timber reckon that it’s a far more sustainable building material than cement. Wood captures and locks in carbon as it grows, and building with it generates much less carbon than building with cement. With well-managed sustainable forestry, experts don’t anticipate any trouble meeting increasing demand.
For a fast-growing and sustainable building material, however, bamboo performs incredibly well. Being a “woody grass” rather than a wood, it grows much faster. It takes most trees 25-50 years to be ready for harvesting, whereas bamboo can be harvested after 3-6 years. One of the 1,000 species of bamboo holds the record for the fastest growing plant at 91cm per day. In the tropics some species can grow up to 40 meters tall. Bamboo is also more efficient than most trees at capturing carbon and releasing oxygen, so bamboo forests have up to four times the carbon density per hectare of spruce forests over the long term.
It’s cheap, light, strong and widely available. In many parts of the world, very tall buildings have been built using bamboo scaffolding—even in Hong Kong, where it’s long been used for building skyscrapers. It may look rickety but apparently traditional builders know from experience what engineers have been able to measure scientifically: that bamboo has higher compressive strength than wood, brick or concrete, and a tensile strength on par with steel. Now these qualities are being harnessed in “engineered bamboo” that’s processed into laminated products. These are apparently comparable with or better than timber for some building applications.
Just a few decades ago few people gave a second thought to the environmental impact or sustainability of construction materials. Now there’s a growing desire for designing sustainability into the whole lifecycle of a building—from sourcing the materials, through constructing, running and maintaining the building to its eventual demolition and recycling.
This is just one example, but there’s now a vast amount of activity and content dedicated to what is increasingly being recognized as the biggest question facing the human race: What changes do we need to make to preserve our environment for future generations? It’s clear that there is an urgent need to apply rigorous design thinking to our problem solving. This means placing an issue in its correct context as part of a bigger system, itself part of a bigger interconnected whole, and designing solutions accordingly. It’s a big challenge, but an exciting opportunity, and one to which inventors and designers the world over are gleefully rising.
