Cities are responsible for around 70% of carbon emissions globally, while buildings account for more than half of this. In the transition towards a zero-carbon economy, the built environment is therefore pivotal.

As one of the first global cities to commit to becoming carbon neutral by 2050, London is at the forefront of developing solutions to combat the many challenges. Last year, New London Architecture (NLA), a membership organisation comprising public and private sector members from across the built environment, published Zero Carbon London, a report that looks at how this is can be done. NLA’s programme director Barbara Chesi explains.

“Probably the most significant priority right now is retrofitting, and built environment professionals are recognising the importance of it. When you demolish a building to create a new one you create a lot of waste, and carbon emissions are part of that. Finding ways to reuse existing buildings is therefore the most effective way of reducing embodied carbon, boosting energy efficiency, and cutting overall emissions in the lifetime of the building. The importance of retrofitting is such that there are calls for this to represent 90% of the work of built environment professionals.

“Another key priority is the focus on long-life, loose-fit, low-energy buildings that can be quickly and easily adapted for different purposes, for example transforming housing into offices, hotels and retail, etc. It is a great example of the flexibility that is needed right now.”

What are the biggest challenges to reducing carbon emissions?

“In our recent member survey, respondents identified the biggest challenge as policy and regulation. For example, a government consultation last May looked at a ban on the use of combustible materials in buildings, including timber. Yet, from a built environment perspective, timber is becoming very important in the reduction of embodied carbon in our buildings.

“The second biggest challenge was a lack of green finance and the fact that the transition to a low-carbon economy is not supported by adequate investment from the government, and that current financial models don’t take into account the longer-term issues of climate change. More investment is needed in order to implement better green finance solutions.

“The third biggest challenge was a lack of common standards and shareable data, notably in relation to measuring and disclosing carbon emissions. There are lots of tools to measure embodied carbon and they are all quite different, producing data that is not comparable. We need to standardise measurements and share more.”

What are the possible solutions within the built environment to tackle carbon emissions?

“In our survey, respondents were asked to name the solutions they believed will make the biggest impact in tackling carbon emissions. Not surprisingly, number one was retrofitting. Number two was adopting a truly circular economy approach, where buildings are designed with elements that can be taken apart and reused, and number three was continuing the transition to clean energy and decarbonisation of the grid.

“These solutions will take time to implement in a way that will make a significant impact; however, we can start doing other things which are equally important and that don’t require long-term transformations. For most of them, we have already the knowledge, skills and technology.

“One of them is to design new buildings that are net zero carbon, for example, using renewable energy sources, and also by using the Passivhaus approach, which is based on the principle of reducing heating demand to a very low level rather than relying on renewables. With efficient insulation, these buildings need less energy in the first place.

“Another important approach is to start calculating the whole-life carbon, including the embodied carbon emissions, of a building. If the building is going to be up for 60 years, you can do a deep retrofit to make it more energy efficient. That will come with some carbon emissions as part of that retrofit process, but they will be offset during the lifetime of the building. Greater London Authority has published a draft guidance on whole-life carbon, and we should be in a position to adopt this approach fairly soon to make better decisions.

“A third quick win is to increase green infrastructure, for example, incorporating more greenery into public spaces. While not directly related to decreasing carbon emissions, the environmental benefits of this are huge.”

“From a business point of view, some of the best opportunities can be seen in the real estate market. Portfolio owners and investors are taking the environmental credentials of their buildings seriously. In the office market, occupiers are increasingly demanding sustainable buildings, not just for the future cost savings on energy bills, but to enhance their ability to attract future talent. Today’s employees want to know that their employer is serious about the climate agenda, and having a truly sustainable building is a clear demonstration of this.

“In the commercial sector, some retrofitted buildings are really pushing the bar in terms of environmental standards. One example is 81 Newgate Street in the City, a retrofit of a 1980s office building that is transforming it into a sustainable, mixed-use building, avoiding demolition and new construction, reducing overall embodied carbon, and improving environmental performance, through natural ventilation and daylighting. It also has more than 1,300 cycle spaces, to encourage sustainable transport, while the greening of roof terraces and other spaces will significantly enhance biodiversity.

“Another example of an extremely sustainable commercial building, this time a new build, is Old Paradise Street in Waterloo – a highly sustainable office space, still in planning, with a mix of workspace and leisure space. It is also a negative-carbon project, a timber-framed building with a cross-laminated timber structure. Timber is a truly renewable material that sequesters carbon as it grows and reduces the embodied carbon of the building.”

What are the likely effects of Covid-19 on the drive to reduce emissions?

“A survey we conducted on this subject last September found that 91% of respondents saw the pandemic as an opportunity to change how we live and become more sustainable. Since the first lockdown, in spite of the tragedy of the pandemic, things we thought could never be done in a short space of time actually happened.

Has the impact of the pandemic changed public opinion on this issue?

“From March to May 2020, carbon emissions in London dropped by 60%. People were aware of the improved air quality, while access to nature became important to their well-being, as they started using active travel, such as cycling and walking. Many of these changes can continue beyond the pandemic but they need support from the city and more green infrastructure: for example, better footpaths and cycle lanes. Without it, things could go the other way.

How has NLA responded to the government’s Ten Point Plan...

...for a Green Industrial Revolution, which was announced last year?

“The general feeling was one of positivity to see the government taking the issue of climate change so seriously, with a plan for achieving zero-carbon targets. However, given the huge amount of emissions that come from buildings, we felt that the built environment should have featured higher on the agenda. We are seeing more investment in new technology for more effective solutions, which is important, but there are things we can do now that will have a more immediate impact.”