The UN conference on climate change – COP26 – in Glasgow this November will be the largest such gathering ever held in the UK. Its significance in the fight against global warming cannot be overestimated. Simon Wyatt looks at the challenge for construction, while Thomas Lane considers the future of whole life carbon assessments

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As the coronavirus threat finally starts to recede, the approach of COP26 should come to dominate the conversation in 2021. As it does so, we need to consider what that means for the built environment.

Postponed from November 2020 because of the global pandemic, and due to take place in Glasgow between 1 and 12 November, the delay has given the industry more time to prepare. Which is just as well, because we needed it.

A year ago, when we were still blissfully unaware of the chaos that the next 12 months would bring, there was almost no conversation around COP26 emanating from the industry. Interest in net zero carbon solutions was starting to grow, but it had not yet reached the fever pitch in demand that we are starting to experience.

Marking five years (now six) since the Paris agreement was signed, COP26 was always going to be a significant milestone in the global fight against climate change. The conference will be the first review of the agreement, which represents the legal commitment of 195 signatory nations to limiting global warming to well below 2ºC.

COP26 will be the largest international conference ever held in the UK. Presidents and prime ministers from around the world will attend and report back on the progress of the past six years, among them Joe Biden, who recently re-signed the Paris agreement on behalf of the US after the Trump administration abandoned it in 2020.

The UK’s committee on climate change recently recommended emissions reductions of 78% by 2035 in order to align with the Paris agreement, and this applies to all sectors, including the construction industry


Since the agreement was signed in 2015, all 195 countries have made climate declarations (so-called nationally determined contributions), but the question is: how do they align with the 1.5ºC to 2ºC targets? As they currently stand, these commitments may only limit warming to 3.3ºC, so the aim of COP26 is to review these and to increase the ambition.

But it is not just the world’s political leaders who will be reporting; industry leaders including those of us in the built environment will also be accountable. The UK’s committee on climate change recently recommended emissions reductions of 78% by 2035 in order to align with the Paris agreement, and this applies to all sectors, including the construction industry which, as we know, is responsible for over 30% of UK emissions.

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Alok Sharma became president of COP26 in January

For the built environment, this reduction applies to new and existing assets, which will all need to be net zero carbon by 2050. But we are already seeing the industry’s preparedness to go much further, with many local authorities setting earlier dates, and developers signing up to initiatives such as the Better Buildings Partnership Climate Commitment and the World Green Building Council’s Net Zero Carbon Buildings Commitment.

Over the past 12 months, the biggest driver in the industry has undoubtedly been finance, with increasing pressure on pension and hedge funds to meet more stringent environmental, social and governance criteria including net zero carbon and climate resilience. Specifically, the recommendations of the taskforce on climate-related financial disclosures, which works to improve reporting of climate-related financial information, have encouraged a considerable increase in reporting. This in turn has helped to ensure increasing pressure on developers from all directions to prioritise net zero carbon and ensure all elements of new and existing buildings meet the challenge.

Assets and portfolios that do not act run the risk of becoming “stranded” and losing value. As decarbonisation requirements increase over time to align with Paris and net zero carbon trajectories, assets that overshoot these targets risk financial penalties, devaluation and potential problems securing funding.

Individual assets’ reduction pathways can be developed to avoid these stranding events using tools such as the carbon risk real estate monitor, which are being used to assess the climate risk of real estate portfolios and highlight potential stranding events. 

As of 24 February, we had just 250 days until COP26. A relatively short period in which we as an industry need to work out what we can do to meet the challenge, and in what timescale.

The UK Green Building Council currently has a taskforce looking at this, and with a dedicated built environment day now confirmed to be part of COP26, we are in a position to showcase the UK’s leadership in net zero carbon to the rest of the world.

Mark Carney, former head of the Bank of England, recently put the urgency of the climate crisis into stark reality, stating that climate crisis deaths “will be worse than covid”. This statement is by no means an exaggeration.

We have already seen one degree of climate change above preindustrial times, and we need to adapt and show resilience if we are to uphold our climate commitments and slow down the rate of change. If we fail even in our short-term goals, we will incur more risk, end up having to adapt more, and ultimate success will come at greater cost – both financial and biological.

Simon Wyatt is the sustainability partner at multi-disciplinary engineering consultancy Cundall 

Our net zero columnist for the countdown to COP26

Simon Wyatt, Sustainability Partner at Cundall

In the months leading up to COP26 Simon Wyatt will be Building’s dedicated net zero columnist, writing regular updates on the construction industry’s progress towards meeting the UK’s targets. 

Simon leads Cundall’s building physics, health, wellbeing and sustainability team. He is a member of the UK Green Building Council’s members advisory committee, the British Council for Offices environment, social and  governance group and chair of the Chartered Institution of Building Services Engineers knowledge generation panel. 

Get a life – a whole life

The London Plan is already putting pressure on developers to reduce carbon emissions from the built environment. A requirement for whole lifecycle assessments now ups the ante. Thomas Lane, group technical editor at Building, reports

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Buried deep in the recently launched London Plan 2021, on page 342, is a new requirement that could be described as a small step for the industry but a giant leap for carbon emissions reduction from construction.

For the first time in regulatory history, big London developers will need to calculate the carbon embodied in the materials, construction, maintenance and demolition of their projects. Policy S1 2 now includes a requirement for developers of schemes referable to the mayor to submit a whole lifecycle carbon assessment and demonstrate actions to reduce emissions.

London has been leading the charge to reduce carbon emissions from the built environment over and above that required by building regulations for a decade. Since 2013 it has insisted on the equivalent of a 35% cut in carbon emissions compared with Part L, a requirement that still stands today. In 2016 it sharpened this policy up by making developers pay a £60 per tonne surcharge for any operational emissions that could not be offset by energy efficiency measures or on-site renewable energy generation. The charge is levied on 30 years of emissions and is payable up front. The new London Plan bumps this up to £95 a tonne.

The requirement to submit a whole life carbon assessment takes London closer to its goal of net zero carbon development. As building energy use reduces, the contribution of the materials, construction and maintenance increases as a proportion of whole life carbon.

There are no compulsory whole life carbon targets in the London Plan but the draft guidance, which will be issued in the summer, includes carbon benchmarks for four building types – offices, retail, education and apartments/hotels. Developers of schemes that don’t meet these benchmarks must explain why.

All of our major clients are considering doing whole life carbon assessments whether they want to or not 

Tom Atkinson, Alinea

 Assessments are required at the pre-planning, planning and completion stages. The last assessment reflects the as-built emissions and again developers are expected to explain why a scheme deviates from the planning stage assessment.

According to Qian Li, a principal engineer at Cundall who specialises in material lifecycle assessment and who advised the Greater London Authority on the whole life carbon guidance, the plan is to use the as-built assessments to set compulsory targets in the next iteration of the London Plan. “They can’t legislate for hard targets because they don’t have enough data to determine what is reasonable or unreasonable,” he says. Li adds the GLA expects to receive 300 to 500 carbon assessments a year, which will be used to build up a whole life carbon database.

Project teams will need to amass a significant amount of information for an assessment. This includes the carbon emissions from raw material extraction, manufacturing and transportation, transport to site, construction, maintenance, repair and replacement, and end-of-life emissions from demolition and waste processing for reuse, recovery or recycling. Developers already have to submit operational emissions calculations as part of a planning application.

The calculations are based on the RICS whole life carbon assessment methodology which in turn is based on a British Standard, BS EN 15978. Li says a lot of the information will come from manufacturers’ environmental product declarations (EPD). Consultants will have to calculate their own EPDs in the absence of manufacturer data. They will also need to use generic data to calculate the carbon impacts of bespoke elements such as cladding systems.

Li says there is an increasing amount of data available and that it is getting more accurate. “The data availability is much better than a couple of years ago,” he says. For example, there was no data available for building services until comparatively recently. Manufacturers are beginning to recognise the value of an EPD for their products. “They are now seeing this as better for them as a marketing tool,” says Li.

According to Li, the development community started embracing whole life carbon assessments last autumn as they wanted to be ready for the launch of the London Plan. Tom Atkinson, an associate at Alinea who is leading the consultant’s carbon initiative, echoes Li’s experience. “All of our major clients are considering doing whole life carbon assessments whether they want to or not, as it is seen as a requirement,” he says. He adds that developers are being driven by tenants who want to occupy net zero offices, with many of the bigger ones adopting ambitious net zero targets.

Unsurprisingly, smaller developers are not as up to speed with whole life carbon assessments, as they are less likely to be involved in schemes where one is needed. Atkinson says smaller developers are likely to embrace whole life carbon assessments whether smaller schemes are referable or not because of tenant pressure, and it is now required as part of a BREEAM assessment.

Who do developers turn to for whole life carbon assessments? The big multidisciplinary firms are well placed to do assessments, including Cundall which has a dedicated sustainability division and long experience of whole life carbon assessment. Li says there is no reason why architects could not do the calculations – Wilkinson Eyre, which did whole life carbon assessments of Gresham St Pauls (see below) says it wants to build up a more thorough understanding of whole life carbon within the practice, including developing the tools to model it. Teams need to collaborate to build up the assessment, structural engineers have the embodied carbon in structural materials at their fingertips, and MEP engineers have the operational data. Li says Cundall kicks off the process in a workshop with the design team to instil an understanding of the impact of material choices on carbon, with the calculations coming at a later stage.

They can’t legislate for hard targets because they don’t have enough data to determine what is reasonable or unreasonable 

Qian li, Cundall

Atkinson cautions that whole life carbon assessment is in its infancy which makes the process much more time consuming. He says people need a bill of quantities – a list of all the materials that go into the building – which is uploaded into a model and combined with carbon metrics for those materials to produce a carbon assessment. “We are providing intricate levels of quantities, probably more than we would do for cost planning at early stages,” he says. “One of the shortfalls of carbon modelling right now is it is still in its infancy; you need to go to a very high level of accuracy at an early stage of the project. Cost planning is the opposite; our cost data has been developed over years and years so we have got composite cost planning rates that we can use at the early design stages so we don’t have to measure everything to the nth degree. We can still give a relatively accurate cost, whereas with carbon you have got to have some representation of all the materials in the model to start with.”

He says that carbon modelling should get easier with time, once more models have been done using as-built data and this knowledge is fed back into the feasibility stage. He says the relatively rudimentary nature of carbon modelling means there could be discrepancies between assessments done at pre-planning, planning and completion stages. “There is a nervousness among those offering carbon calculation as a service if there is likely to be shortfalls in the model. I imagine there is a whole industry discussion about PI [professional indemnity] and how that comes into play if there is going to be a carbon tax and the advice that was given in the carbon model was inaccurate; who is liable for that?” Atkinson adds that Alinea is happy to give high-level early guidance on carbon ranges for building elements where he says it can add the most value but is steering clear of detailed carbon assessments for now.

One of the shortfalls of carbon modelling right now is it is still in its infancy; you need to go to a very high level of accuracy at an early stage of the project

Tom Atkinson, Alinea

 Part of the rationale behind the whole life carbon assessment requirement is to raise awareness of the issue, which will help change behaviours. Atkinson says there is already evidence of this happening. “It is influencing: a project I worked on, we set a carbon budget and broke it down into various components including the superstructure,” he says. “The carbon target directly influenced what frame was adopted for the building; the cost came second to that. The carbon target was higher on the agenda than the cost of the superstructure.” The analysis was carried out on an office building; initially steel was chosen for the frame but this was changed to a timber and steel hybrid once the analysis had been done. “That is a great example of conversations that were never being had as little as two years ago, and now the conversation is directly saying we want to make this structure low carbon, we recognise there is going to be a cost premium, let’s go for it.”

Li agrees that carrying out assessments is changing material choices. “People are specifying locally sourced materials; some are specifying more cement replacements in the structure or aluminium made from recycled content. We have seen more people using timber.” He warns that early decision-making is important to ensure the specification is realised on site and to keep costs in check. “If you leave it to the contractor, it won’t necessarily happen. If you specify this early on it will be cost neutral, but if you change it towards the end it will either be too late or too costly.”

Despite the challenges, Li welcomes the GLA’s move. “For me, I am quite pleased, the next version will have more data behind it, will be more stringent, and the industry will be better prepared,” says Li. “I’ve been doing this for 10 years; it is encouraging to see it becoming more mainstream.” Atkinson is more cautious, because the modelling needs more development, but accepts this will improve. He says: “We will be having a very different conversation in two years’ time, because we will have a lot more data behind the targets and it will be a case of do it, or even better it.”


Reducing carbon at Gresham St Paul’s

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Source: Dirk Lindner

An appraisal of Garrard House, a 1990s office building, revealed that a full refurbishment would have a lower whole life carbon impact than new build.

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Source: Dirk Lindner

The top two floors were removed and replaced with three floors – this added net lettable space and allowed the inclusion of external terraces. Developed as a speculative office, the building is almost fully let

Gresham St Paul’s is a recently completed 10-storey office building in the City of London. Designed by Wilkinson Eyre and developed by Stanhope for building owner Afiaa, the building is a refurbishment of Garrard House, which was completed in 1998 as the headquarters for investment manager Schroders.

An appraisal and feasibility study was carried out to assess how to bring the site up to current grade A office space standards. This considered new build or refurbishment of the existing building, with a whole life carbon assessment carried out as part of the process.

The appraisal established the building had good floor-to-floor heights but the services were worn out and there were not enough lifts or toilets to meet modern standards. Adding these would eat into net lettable space, and digging down to create extra room for plant was not possible because of the archaeological remains under the building. The carbon assessment considered new build as well as a full or light touch refurbishment. “We came to the conclusion a full refurbishment was more efficient,” says Sam Wright, the Wilkinson Eyre director leading the project. “You can bring the building to market much more quickly as it saved six months on the programme.” This option also had the lowest whole life carbon impact.

Extra space was created by infilling an atrium and adding an extra floor to the building. Engineer Waterman had designed the original structure and had the data to demonstrate the steel frame could take the additional loads. Additional risers were needed as the space was now multi-tenanted, with each tenant needing a dedicated services supply. The original Portland Stone facades were good-quality and retained. The aluminium window frames were also kept but modified to accept thicker, more thermally efficient double-glazing units.

The whole life carbon assessment was carried out in accordance with the RICS methodology and includes emissions from partial or full demolition of the existing building, products and materials, maintenance and replacement, construction and operational emissions.

Wilkinson Eyre expresses the whole life carbon impact of the three options in terms of kilograms of CO₂ per person over the building’s 60-year life. This accounts for the fact the original building could accommodate 1,460 people but the refurbished, enlarged building can accommodate 1,970 people, the same as a new build. Leaving the building untouched would result in the lowest carbon footprint, of 63,026 tonnes, equating to 719kg CO₂ per person per year. The refurbished building has a carbon footprint of 65,391 tonnes, slightly higher than doing nothing but as it holds more people this equates to a lower whole life carbon footprint of 553kg/CO₂ per person per year. A new build produces the biggest impact, with a carbon footprint of 72,051 tonnes, although the extra space means this is still better than doing nothing as the lifetime carbon footprint for each person is 610kg/CO₂ per year.



Net Zero Live logo 2021

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