Wood the answer to zero carbon status by 2030
University and Scion research shows how New Zealand can achieve ‘‘zero carbon’’ in our thirdbiggest area of emissions, buildings.
Our three main greenhouse gas (GHG) emission sources are transport, agriculture and buildings.
How we build the latter has a significant impact on how well we respond to climate change.
Having visited the Tokyo Car Show this month, it is clear to me that, by 2050, most land transport will be electric. Agriculture is on its own pathway to working out how to play its part in that timeframe.
The potential for a big, early climate change win is in what we build with.
Buildings cause GHG emissions in two ways: the embodied carbon from the extraction, manufacture and transport of the materials used, and the ongoing emissions from the energy used by the building.
Nearly all electricity in New Zealand is from renewable sources so measurement of ongoing energy use, known as ‘‘Life Cycle Analysis’’, is fairly irrelevant in terms of climate change.
Don’t get me wrong, it’s always good to save power for economic reasons, but right now the biggest show in town is climate change.
So when it comes to buildings and climate change, it is only the upfront embodied carbon in the materials that is relevant in New Zealand.
Hands down the products that cause the most climate change damage are concrete and steel.
They account for an estimated 13 per cent of greenhouse gas emissions globally between them. Steel is 5 per cent and cement 8 per cent.
Both require huge amounts of fossil fuels and energy to extract, transport and process. Unfortunately carbon dioxide is also a significant by-product of both.
Contrast this with building in wood.
The trees spend 27 years sequestering CO2 from the atmosphere, are taken short distances to local mills and are then converted to timber using energy derived from the bark and sawdust from the milling process.
This year’s EECA Major Energy User award went to New Zealand’s largest sawmill Red Stag Timber, which generates all its own power and heat, and is effectively carbon neutral.
Speaking at the Architecture Climate Summit in London last month, Dr Michael Ramage, an
Wouldn’t it be smarter if instead of using steel/ concrete and then having to convert farms to forestry to soak up the resulting CO2 we just used more wood in the first place?
architectural engineer and University of Cambridge academic told the audience: ‘‘If we invented concrete today, nobody would think it was a good idea.
‘‘We’ve got this liquid and you need special trucks, and it takes two weeks to get hard. And it doesn’t even work if you don’t put steel in it.’’
The International Energy Agency estimated the cement and steel industries emitted 4.6 billion tonnes of CO2 last year. Meanwhile, all around the world countries are pursuing billion-tree programmes to soak up that very same CO2.
Wouldn’t it be smarter if instead of using steel/concrete and then having to convert farms to forestry to soak up the resulting CO2, we just used more wood in the first place?
I do wonder if farmers with steel sheds realise the irony of them complaining about the farm next door going into trees.
To understand the benefits of substituting steel and concrete with wood, one must look at actual buildings and the relative tonnes of each material used under the different structural material options.
The most comprehensive such study was conducted by University of Canterbury, in conjunction with Victoria University of Wellington and Scion.
The study used a six-storey, 4200- square-metre building and highlights the opportunity for New Zealand. For any given concrete or steel building, we need two wooden buildings to offset the CO2. This 2:1 ratio should be our national target for 2030.
This is now possible. Wood solutions such as Cross Laminated Timber (CLT), LVL and glulam are being used in buildings up to 20 storeys internationally, and locally we now have the engineers, manufacturers and builders with the experience to make it happen.
The success Housing Corporation has had with CLT in cost, speed and earthquake resilience in its mid-rise apartments shows what is possible.
We’re all bit players in the overall climate change solution. We may ask, what impact can I alone have? But many people do have a say in what buildings are made of, and those choices all add up.
If we as a country embrace this target of Zero Carbon in Buildings by 2030, others will follow.
New Zealand’s biggest contribution to climate change may not be our relatively small global contribution, but rather the leadership we show that results in larger countries around the world following suit.
That leadership starts at home in the investors, architects, and engineers responsible for making choices about what materials to use in the buildings they commission going forward.
Already some businesses are asking for ‘‘carbon neutral’’ buildings. This needs to become the norm by 2030 if the country is to hit the Zero Carbon target by 2050 that is now being legislated.
There is no bigger potential for that leadership than with the government, the largest commissioner of building work in the country. That also makes it New Zealand’s largest-single CO2 emitter.
It is fully aware of the university research, as MPI commissioned it, and that is no doubt what underpinned the Wood First policies adopted by all three coalition government partners.
And yet that Wood First procurement policy has not yet been implemented.
Fail to implement it, and the government will not only break an election promise and lose the support of a large industry, but will also be open to claims of emission hypocrisy and not being genuinely serious about climate change.
Implement it, and New Zealand will be a true global leader in climate change, enhancing our pure clean green branding for the benefit of all exporters, giving us credibility in global climate forums and supporting regional New Zealand.