Six Steps For De-Carbonizing Construction

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Robison Wells

At an October construction technology conference in Singapore, Atkins CEO Keith Clarke told executives that if global temperatures rise two degrees Celsius in the next 20 years then instead of worrying about their pensions they should instead “buy a shotgun” because of “mass migrations, upheaval, and extinctions.”

While it’s easy to find such language extreme and alarmist, there truly is no denying that the world is facing a reality where lowering carbon emissions is a public, political, and scientific issue.

Describing a world where such rapid climate change happens, Clarke compares the kind of cultural change something that has only ever happened so rapidly during wartime, “and never on this kind of scale.”

In regards to the changes that we will need to go through, he said “Technology is going to come to your site. The question is, does science come to your boardroom?”

The University of Leeds, and the international cities group C40 Cities, has produced a list of six items that need to be on the minds of construction companies:

• Use materials more efficiently;

• Use existing buildings better;

• Switch to lower-emission materials;

• Use low-carbon cement;

• Recycle building materials and components;

• Use low-emission construction machinery.

Taken together, the Leeds study anticipates that a progressive estimate in carbon emissions would be a 29% decrease, and 44% as an ambitious estimate.

In detail, the items offers these benefits:

1) Material efficiency: The idea of material efficiency is that quite a bit of carbon emissions come from concrete and steel, and studies from Cambridge University shows that, on average, 10,000 studied steel beams are carrying half the load they were designed for. By decreasing the size of the steel and concrete in these structures, we would save significant carbon emissions.

2) Use existing buildings better: the study shows that the number of long-term vacant buildings in the study (based around Cambridge) showed 216,186 long-term vacant buildings, while 70,430 households were homeless or threatened with homelessness. By designing buildings in such a way that would have they can be repurposed to use the buildings around the clock, leaving them unoccupied for a shorter amount of time.

3) Switch to lower-emission materials: The goal here is to use sustainable timber instead of steel and concrete. Timber (trees) absorb carbon from the atmosphere, so growing more trees and harvesting them on a grander scale can save carbon emissions. Plus, timber weighs less, leading to lower concrete costs. This is not a pipe dream. As we have reported here before, architects are racing to get to the tallest tower made from timber.

4) Develop low-carbon cement: because production requires limestone to be heated to extreme temperatures, cement is a big beast in the world of polluters. Studies calculate that four billion tons of cement are produced each year, which accounts for 8% of all global CO2 emissions.

5) Recycling building materials and components: Construction waste accounts for as much as 30% of all waste according to the Cambridge Study—everything from bricks, gypsum, wood, glass, plastic, metals, solvents, and asbestos. In 2017, Amsterdam realized the potential benefit and began what they call “urban mines,” repurposing steel, copper, aluminum, and zinc.

6) Low-emission construction technology: Caterpillar and Volvo are already working on this, developing electric diggers. Adopting low and zero emission construction machinery, through electric and biofuel vehicles, would cut emissions in cities by up to 10%.

As Clarke said in his address in Singapore, “There are no pathways to getting there without all aspects of the economy doing their bit.”

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