No single building in New Zealand symbolises unintended pollution more than the Beehive building. Photo / Mark Mitchell
OPINION:
Ever since the Romans began to build with fired-clay bricks and concrete, construction has been a polluting industry. Buildings account for emissions in three main ways: coal boilers for heating; energy consumption; and the "embodied carbon" resulting from the materials used and the construction process.
The embodied carbon in the materials used is by far the largest component. Local specialist consultancy firm Thinkstep estimates embodied carbon accounts for 10 per cent of New Zealand's greenhouse gas emissions. Concrete and steel make up the lion's share of these emissions. According to the Economist magazine, cement accounts for around 8 per cent of global greenhouse emissions and steel 7-9 per cent. If either was a country it would be the third largest emitter in the world after China and the United States.
Historical use of these hard-to-abate polluting products is to a large degree why the world is now facing a climate change crisis.
And no single building in New Zealand symbolises this unintended pollution more than the Beehive building in Wellington, with its thousands of tonnes of concrete and steel.
This emerging realisation means that in the years to come people will look at such buildings in the same way we look at asbestos or cigarettes now. It is no exaggeration to point out that in the same way fumes and fragments from these products cause cancer when breathed by humans, so too is the carbon dioxide from concrete and steel choking the planet's temperature.
Now the dilemma we have is that steel and concrete are really useful in certain circumstances. Thermal mass on ground floors (concrete), very wide spans (steel). The key in future is to use them only where absolutely required. Fortunately in the past two decades mass timber products and building designs have been developed for practically every building type and application.
The best example of this is the recently opened 85m tall wooden skyscraper in Norway known as the Mjostarnet tower. But more likely the typical New Zealand building will look like the beautiful "25 King" building in Brisbane (pictured below), which was recently developed by Lendlease.
According to Aurecon, the tenants, "The 9-storey plus ground superstructure utilises a combination of revolutionary engineered cross-laminated timber (CLT) and glulam (glue laminated timber). The glulam is used for the structural beams and columns, and the CLT for the floors, lift shafts and escape stairs. The engineered timber has a lower carbon footprint than traditional building materials, and is sourced from certified sustainably-managed forests. It also allows for precise offsite prefabrication and safer onsite construction."
New Zealand's new building stock can achieve carbon neutrality by 2025 by optimising building design to maximise these mass timber products and use concrete and steel only where necessary.
This is where the Government is on the right track with policies and regulations coming into force next year. Its Building for Climate Change programme will home-in on embodied carbon emissions. All buildings will be required to measure their CO2-equivalent emissions, and over time there will be a sinking cap on the amount of CO2 per square metre allowed to comply with the Building Code.
Government-funded projects will be the first needing to comply, with Cabinet announcing in October that from now on the procurement policy is that all such buildings must measure emissions and choose the lowest option or explain why not. Economic Development Minister Stuart Nash is demanding this from agencies and departments and has committed to enforcing it strictly.
It is appropriate that government uses its procurement to lead the way. As the Economist put it "Governments can help nudge the industry to use more wood, particularly in the public sector — the construction industry's biggest client. That would help wood-building specialists achieve greater scale and lower costs. Zero-carbon building regulations should be altered to take account of the emissions that are embodied in materials. This would favour wood as well as innovative ways of producing other materials."
New Zealand is not the first to implement these policies and regulations – governments around the world have led the way. As the Economist observes "Governments in the rich world are now trying to promote greener behaviour by obliging developers to build new projects to 'zero carbon' standards".
Increasingly the scientific advice is that to achieve the Paris Accord target of restricting climate change to 1.5C in 2050, we must make the changes this decade. In September 40 global cement companies committed to delivering a carbon-neutral cement by 2050. Unfortunately, that is just too late. While kids smoking cigarettes can choose not to breathe in, the planet cannot.
- Marty Verry is CEO of the Red Stag group of companies invested in property development, forestry, sawmilling, cross-laminated timber and pre-fabrication.