In November last year, Norwegian architecture firm Snøhetta came out with a bold claim: that its global practice would aim beyond carbon neutrality and strive to make all its buildings carbon negative within the next 20 years. Co-founder Kjetil Thorsen said that would mean initiating projects over the next 10 years that would become CO₂ negative in the cradle-to cradle/circular economy/regenerative design definition.

Snøhetta’s buildings would create an environmental benefit, generating enough energy to compensate for carbon emitted during the production of building materials, construction, operation, decommissioning at the end of the building’s life and reuse beyond.

Reaching that goal begins with counting – understanding the embodied energies of materials used in a building. In Snøhetta’s estimates, 85 per cent of a building’s carbon emissions are generated by materials and construction, and just 15 per cent are produced over the building’s operational lifetime and during decommissioning. Thorsen argues for repaying the carbon debt of the building by producing clean energy from day one. In the Snøhetta vision, that means generating power using photovoltaic panels.

Today’s photovoltaics don’t make that easy. Snøhetta reckons it takes around 60 years before a building’s solar panels have generated enough power to pay back all the carbon emitted over the building’s lifetime. Not to mention that it takes around six years to pay back the embodied carbon in the solar panels themselves. 

Thorsen puts his faith in advances in nano-technology solar panels – micro-scale 3D surfaces, possibly with built-in batteries – which will allow buildings to generate clean energy more efficiently and become carbon positive more quickly. Bravo, although I always have some unease when arguments are reduced to ‘technology saves the day’. 

But Snøhetta also recognises there are other pathways to low embodied carbon via using more carbon sink materials – mostly timber – more efficiently. I caught a glimpse of what this future might look like last November at Crown Research Institute Scion’s new three-storey campus building rising up in Rotorua. The structural innovation here – a collaboration by Irving Smith Architects, RTA Studio and Dunning Thornton Consultants – is the building’s exceptionally slender engineered timber diagrid, which take the building’s structural load. 

Despite the doing-more-with-less innovation, it’s distressing to hear the building cost is still about five per cent more expensive than it would be if the structure were steel. That’s without factoring in any CO₂ emissions. Do that costing and the timber structure is streets ahead in helping the planet. 

As this building nears completion, it’s vital that it’s assessed properly, taking into account all CO₂ emissions involved in the building process, including the way in which the timber was harvested. We know timber – especially pinus radiata – is very energy efficient, producing few CO₂ emissions during production and capturing carbon for its entire lifespan. What we need to know is whether that adds up to carbon neutral or better. Setting benchmarks for whole-life carbon modelling and post-occupancy evaluation will be vital for making a difference in the climate crisis and for providing useful indicators on the way forward. 

Let’s hope Scion, specialising in research, science and technology development for the “forestry, wood and wood-derived materials and other biomaterial sectors”, moves soon to make this a priority. With the passing of the Zero Carbon Act last year setting New Zealand on a path to a zero-carbon future, such actions seem more relevant than ever. The Act means major decisions made by the government will now be considered under a climate change lens. It also requires a ‘climate impacts assessment’ for policy and legislative proposals that are designed to reduce emissions, or which are likely to have consequential impacts on greenhouse emissions of greater than 250,000 tonnes a year. 

If the government is serious about such aims, you would hope it might take a leadership-by-example approach, beginning with an energy audit of all the buildings it occupies, including those it rents. That might lead to an upgrading of existing buildings and perhaps even promoting the design of regenerative buildings that take carbon out of the atmosphere. Giving back more than we take. Such a proposition has huge implications for architecture and would mean, for example, a massive rethink of proposals like Warren and Mahoney’s speculative master plan for Ngāti Whātua Ōrākei for a vacated Ports of Auckland site (see page 20). Surely, the proposition of moving the port first needs to be subjected to a government ‘climate impacts assessment’ and any design proposal rigorously scrutinised under a climate change lens: scrutiny that, sadly, seems absent at present.  

Schemes like this raise a question: Are New Zealand architects on board with any of this? Yes, we have Architects Declare and some 93 firms signed up to its ambitions but, as yet, the NZIA has not expressed a view. In contrast, the RIBA is aiming for net-zero – or better – whole life carbon for new and retrofitted buildings by 2030.

Is New Zealand architecture currently stuck in an outdated mitigation paradigm where, at best, firms are striving for architecture that’s operationally carbon neutral and only sustains its own existence? Surely that has to change. What’s the point in buildings that perform magnificently in use if it takes decades or more to pay back the carbon enissions that went into their construction? Where is the New Zealand version of Snøhetta, striving to give back more than it takes?

This article first appeared in Architecture New Zealand magazine.

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