Just a few weeks ago the IPCC issued its latest report with a stark warning about how long we have left to moderate CO2 emissions and to halt global warming. It is no longer enough to reduce emissions, we need to start actively reducing the CO2 already in the atmosphere.
The planting of more trees is the only realistic method we have of reducing atmospheric carbon but moves to encourage more forests are failing to generate anywhere near the levels of required.
Furthermore, trees are only really effective at carbon absorption during the growth stages. Once they mature, the wood needs to be harvested and new trees planted. To reduce carbon on an industrial scale, we need to be generating working, sustainable forests that are geared towards the massive task in hand.
Grants and encouragement rarely work. The simple truth is that we will only create more forests at the scale required if we massively increase demand. We also need a use for the harvested timber to ensure that the CO2stored is permanently secured.
When we use cross-laminated timber (CLT), we create long-term storage and we also offset the potential emissions from materials such as concrete and steel, which have high levels of embodied energy. The more we build using CLT, the more carbon we can store and we create a market for timber that will drive reforestation.
The UK has led the world in the adoption and development of a CLT architecture, and our recently published 100 Projects UK CLT book demonstrates the breadth and diversity of the buildings that have been delivered in recent years.
It showcases projects by a range of architects, including Duggan Morris Architects, Haworth Tompkins and Feilden Clegg Bradley Studios, as well as leading developers, such as Berkeley Homes and Lendlease, and blue-chip clients, including GlaxoSmithKline, Sky UK, Jaguar Land Rover, Maggie’s, and the Education Funding Agency.
It shows that this material is not a trend but represents a fundamental change in the way we deliver buildings – a construction revolution.
Buildings constructed from CLT can be carbon neutral or carbon positive, meaning the construction of the buildings either does not increase global greenhouse gas emissions or better, acts as a carbon store, taking carbon emissions out of the environment.
Because CLT is sourced from sustainable forests, a renewable resource, CLT construction provides a natural and scalable form of carbon sequestration.
The book demonstrates that the quantity of carbon sequestered through the construction of the 100 buildings is equivalent to 19,819 tonnes of waste being recycled instead of going to landfill, or the emissions produced by:
- 12,180 passenger vehicles in a year; or
- 23,700 personal return flights to New York; or
- 6,142 homes in a year
Just over 100 years ago, structural concrete was given new possibilities through innovative engineering. Concrete was first widely used by the Romans for sea defences and later for ambitious structures such as the Pantheon. The first practitioners of modern concrete in the late 19th century mimicked the architecture of masonry, however, as the engineering possibilities developed, a new architecture emerged that is now emblematic of the 20th century. From this new form of construction came a new urbanism that is now global and characterises at least a part of most cities of the world.
A century after the introduction of modern concrete, engineered timber is following a similar trajectory. Early adopters of the new material mimic the existing architectural forms, but as the new engineering possibilities are developed, a new architecture emerges, which is emblematic not just of the characteristics of the material but of our relationship with our environment.
The transition from the age of concrete to the age of timber reflects the changing relationship of humanity to the planet as we are called to account for the impact of the last century on our climate and ecosystems.
Architecture is political, and as architects we have the responsibility to address the principal issues of our age. None is more critical and with such a severe potential as the threat of climate breakdown.
The built environment is the primary source of CO2 emissions, we must address the embodied energy in our construction. Using CLT is not simply ‘good for the environment’, it has the potential to save the world.
100 Projects Uk CLT is available to download here
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