Decarbonising the construction sector

A report commissioned by the New Zealand Green Building Council estimates construction accounts for around 20 per cent of the nation’s carbon emissions.

In Under Construction: Hidden emissions and untapped potential of buildings for New Zealand’s 2050 zero carbon goal researchers say the sector pumps out close to three million tonnes of carbon each year. That’s the same as having a million extra cars on the roads.

The report was written by sustainability consultant Thinkstep. It goes on to say the industry could cut emissions by 1.2 million tonnes, which would have the effect of removing almost half a million cars.

This figure is what is known as “embedded carbon”. It counts the pollution caused by building and building materials. It is separate from the carbon emitted from activities like heating and lighting when the building is in use. Steel and concrete make up more than half the carbon footprint of residential and nonresidential construction.

Thinkstep says there is untapped potential to reduce carbon. It could fall as much as 40 per cent by 2050 — the year government has set for New Zealand to be carbon neutral.

Rather than look for a magic bullet, the consulting firm says the goal is achievable through lots of smaller changes throughout the construction supply chain. The key is for everyone in the sector to co-operate.

Construction material suppliers need to move to low carbon manufacturing technologies. While customers must consciously choose less polluting materials. It would help if public and private procurement policies reflected these priorities. And the New Zealand Emissions Trading scheme has to account for the emissions in imported materials. Thinkstep also recommends improving the availability of data so that everyone can make better informed decisions.