Yet the opportunity they represent to tackle global warming and therefore climate change, as well as energy security and resource scarcity, continues to be missed.
It has become second nature in the construction industry to consider ‘operational carbon’ – the emissions related to the energy needed to run a building. These are the numbers you see in the Energy Performance Certificate of your home.
However, ‘embodied carbon’ is still often no more than an afterthought. Yet addressing the emissions related to the construction of a building – from the manufacture and transport of building materials to maintenance of the building fabric through to dismantling and disposal – could result in enormous savings for the environment.
It is like fretting over the day-to-day bills while happily ignoring the mortgage.
While you can intervene along the way to improve the carbon emissions of a building’s energy use, there is nothing you can do later about the emissions during construction. Not only that, interventions to improve a building’s energy efficiency actually make the total embodied carbon worse. This short-term thinking characterises most of the current approaches by governments and regulatory bodies worldwide.
But there is no reason why ‘mortgage’ and ‘bills’ cannot be thought of together to achieve better performance and reduce the environmental impacts caused by buildings over their life cycle, not just while we use them.
Mitigation strategies are many, and everyone has a role to play – from policymakers to us, the building users.
Building standards, for example, currently just tell people to build energy-efficient buildings from an operational perspective. But with the Paris Agreement and the Climate Change Act, the UK has strict carbon budgets to meet in the coming years. It is vital that we address carbon emissions throughout the entire life cycle of a built asset.
New materials need to be developed that can deliver the buildings of the future in harmony with the one planet we have.
Timber is great, of course, but it will not meet future demands because of population growth, increased urbanisation, and issues such as deforestation and land use change. So it is time to move away from sentimental discourse and look at hard facts.
Construction activities will need to catch up with the technological development that all other sectors have seen in the past decades. In spite of some very modest advancement, we are still building as we did in the past. No other sector has shown such a reluctance to embrace what new technologies can offer, and this needs to improve quickly.
Buildings will also need to be designed in a different manner, taking into account that resources will be so scarce in the future that built assets will have to be disassembled, not demolished.
This concept likens buildings to ‘material banks’ that borrow materials from nature for their service life in order to return them when they are no longer needed, be it in 25 years’ time or two centuries from now, an approach in line with the transition to a circular economy. At Edinburgh Napier’s Resource Efficient Built Environment Lab (REBEL), we are investigating how to lessen the impact of building structures and structural materials on the environment whilst guaranteeing the same levels of safety, performance, and resilience.
We are also looking into issues related to phenomena currently neglected in the quantitative assessments of the sustainability of our built environment that could, however, adversely affect human health, such as air quality and pollution.
We are developing strategies that are in line with the circular economy, and will assess the availability of resources when devising potential pathways towards the built environment of tomorrow.
This holistic thinking will need to become mainstream in the future if sustainability targets are realistically to be achieved. Focusing on one part of the building’s life and not the other is puzzling to say the least – we are effectively trying to take the carbon out of our energy bills while paying no attention to the carbon in the buildings themselves.
The good thing is that the financial case does exist to pursue a different avenue; less carbon means less energy and/or less materials and therefore lower costs. This often should, and indeed does, turn into a saving for the customer.
Addressing these issues will therefore make the buildings of the future cheaper, and this will be crucial given the housing challenges we are about to face.
Dr Francesco Pomponi, Principal’s Research Fellow at Edinburgh Napier University and head of the Resource Efficient Built Environment Lab (REBEL).