By Ed Dean, Director of Development

With just a few years left to avoid climate catastrophe, we need to tackle a massive driver of global heating – our buildings. How we build new ones, how we use the ones we currently have, and how we make old ones more efficient. That’s the message behind World Green Building Week, which ends on Sunday.

Construction and use of buildings is responsible for 39% of global energy-related emissions, according to the World Green Building Council – so a more sustainable approach is crucial as we fight to reach net zero carbon emissions as soon as possible. But focusing on sustainability can also create places we are truly happy to live, work and play in. Buildings that are more comfortable, more beautiful, and that reconnect us with nature.

The task ahead is huge, but we can do it if we keep two key principles in mind. The first is considering the carbon impact of a building’s entire life – from the creation of the first brick or roof beam, to how the building performs a century later. Second, we need to make sustainable buildings that really meet people’s needs and desires – recognising that green design is an opportunity, not a burden.

The success of Ashden Award winning-innovators shows that many of the ideas we need have already been proven – now we need the investment and political will to scale them up.

There are willing hands ready to take on the challenge. Last week’s Architecture of the Emergency event at London’s Barbican centre brought together architects, campaigners and academics. Their message was clear: a new, more radical approach is urgently needed.

It was great to see the energy of Extinction Rebellion and others mesh with the expertise of forward-looking practitioners and thinkers. Collaboration and new partnerships will be vital as we take on this enormous challenge. One big talking point was the need for more innovation at the beginning and end stages of the building life cycle.

Seeds of change: better buildings through nature

More than one third of the emissions generated by our buildings are ‘embodied carbon’ – emissions created during the construction process, including making construction materials and moving them to their final destination. But this vital area is often overlooked, and as new buildings are built to higher standards of efficiency, the embodied carbon can become even more significant.

So what solutions are out there? One, championed by event speaker and sustainability-focused architect Andrew Waugh, is cross-laminated timber (CLT). Growing trees absorb CO2, but slow down as they mature. Using mature trees to make building material such as CLT, and planting young trees in their place, creates a cycle that encourages allows construction and protects our climate.

How else can natural materials lower emissions? Innovations such as hempcrete (made from hemp and lime) help builders replace concrete – a huge driver of global warming – with a plant-based alternative. As well as providing efficient insulation, hempcrete helps to control humidity, and past Ashden winner Hembuild used its hempcrete product in homes, shops and schools around the UK. Another innovator, this time tackling the use of fired bricks, is the Haileybury Youth Trust, which is training people in Uganda to build with interlocking compressed earth blocks made mainly using local soil. The process is much more sustainable than building with fired bricks, and can produce better quality buildings.

A Haileybury Youth Trust Project

Retrofit: collaborate and think big to improve old buildings

Another overlooked area is retrofitting – making older buildings more energy efficient. Many buildings stay in use for well over a century, but even those built recently can be shockingly inefficient.

Here, too, there are effective and proven solutions. The Energiesprong model uses off-site manufacturing to quickly deliver high-impact, whole-house retrofits. Crucially, it’s designed to deliver the benefits households really want – comfortable temperatures and enough electricity and hot water to meet their everyday needs.

Retrofitting can also tackle the pain of fuel poverty. The Cosy Homes in Lancashire scheme has seen councils band together to increase their buying power as they commission retrofit work such as solid wall insulation. The partnership seeks out those most in need of support, and works closely with local health agencies – another example of great collaboration.

The most promising kind of retrofit innovation allows us to work quickly and deliver big impact. One great example is Q-Bot – the company uses a robot to improve under-floor insulation in older homes. A job that once took weeks can now be done, with minimal disruption, in a day.

Energy in use: Passive design and software solutions

While embodied carbon and retrofitting are particularly neglected areas, the way we use and manage energy in our buildings can also be radically improved. Solutions range from the high tech to the elegantly  simple.

In the latter category is ‘passive design’ – championed by architects such as Architype, and bodies such as the Passivhaus Trust – which uses building layout and material choices to minimise or even get rid of the need for artificial heating and cooling. Other innovators, such as software start-ups Demand Logic and Equota Energy, are using ‘big data’ and artificial intelligence to transform how energy in buildings is measured and managed.

The climate emergency grows every year, and our ambition and effort need to keep pace. Will investors and politicians think big enough – and can they match the energy that lit up the Barbican Centre last week?