World Green Building Council Calls for Radical Reduction in Upfront Carbon Emissions

©. World Green Building Council

People are finally beginning to take this issue seriously.

Upfront Carbon Emissions (UCE) is a term first used on TreeHugger to describe the CO2 emitted during the construction of a building, the carbon burp that comes from making the materials that go into a building, transporting them and assembling them. I thought it was a better term than "embodied carbon" that is traditionally used in the industry, because, well, it is not embodied at all; it's out there in the atmosphere now.

The biggest problem with embodied carbon calculations is that they get plugged into a lifecycle analysis to see, for example, if more foam insulation saved more money in operating energy over the life of the building (say, 50 years) than one used making the foam. This gets complicated. Having a short attention span, I wrote forget about lifecycle analyses, we don't have time. What matters is the carbon we are pumping out now.

More and more people are beginning to think this way. At a recent Architecture of Emergency climate summit in London, Andrew Waugh complained, and was quoted in Dezeen:

We have BREEAM and LEED that look to control or reduce the amount of carbon at construction puts into the atmosphere, but this is measured over a period of 50 years. If you build a building now it's in 50 years' time when the carbon is measured from that building. We don't have 50 years.

The World Green Building Council is recognizing this problem, too, and has issued a new report: Bringing Embodied Carbon Upfront.

Buildings are currently responsible for 39% of global energy related carbon emissions: 28% from operational emissions, from energy needed to heat, cool and power them, and the remaining 11% from materials and construction.

But as buildings become more efficient and operational emissions are reduced, then the emissions from materials and construction go up in proportion.

Towards the middle of the century, as the world’s population approaches 10 billion, the global building stock is expected to double in size. Carbon emissions released before the built asset is used, what's referred to as ‘upfront carbon’, will be responsible for half of the entire carbon footprint of new construction between now and 2050, threatening to consume a large part of our remaining carbon budget.

The WGBC has a dramatic and radical proposal:

  • By 2030, all new buildings, infrastructure and renovations will have at least 40% less embodied carbon with significant upfront carbon reduction, and all new buildings are net zero operational carbon.
  • By 2050, new buildings, infrastructure and renovations will have net zero embodied carbon, and all buildings, including existing buildings, must be net zero operational carbon
  • .

They explain the difference between embodied and upfront emissions in greater detail in the report:

Carbon emissions are released not only during operational life but also during the manufacturing, transportation, construction and end of life phases of all built assets – buildings and infrastructure. These emissions, commonly referred to as embodied carbon, have largely been overlooked historically but contribute around 11% of all global carbon emissions. Carbon emissions released before the building or infrastructure begins to be used, sometimes called upfront carbon, will be responsible for half of the entire carbon footprint of new construction between now and 2050, threatening to consume a large part of our remaining carbon budget.

Many people and groups have been calling for buildings to be net zero in their operating carbon emissions, but this is the first time that I know of that anyone has ever called for net zero embodied carbon, defined as:

A net zero embodied carbon building (new or renovated) or infrastructure asset is highly resource efficient with upfront carbon minimised to the greatest extent possible and all remaining embodied carbon reduced or, as a last resort, offset in order to achieve net zero across the lifecycle.

The report does not take a simplistic "ban concrete" position, noting that the concrete and steel industries are taking action to clean up their carbon footprint. However, it does put a deadline on it; hitting the 2030 deadline alone will mean a dramatic reduction in their footprint or their replacement with renewable materials. The 2050 deadline is much, much tougher; everybody, not just concrete and steel, has to get on the case fast or be left behind.

Many other materials such as gypsum, glass, aluminium and plastics also contribute to total embodied carbon. These materials perform important functions in the same way concrete and steel do. While there may be lower carbon alternatives, these are not always available at scale, and achieving net zero embodied carbon will require significant decarbonisation efforts within all these sectors. Encouragingly, for these and other heavy industries, significant emissions reduction opportunities already exist, both in their production and in how they are specified and used. In some parts of the world, sectoral decarbonisation roadmaps have already been established.
Development stages

© World Green Building Council

Every material we use, including my beloved mass timber, has a carbon footprint. That's why the WGBC first principles are so important, where Principle 1 is to Prevent, to "question the need to use materials at all, considering alternative strategies for delivering the desired function, such as increasing utilisation of existing assets through renovation or reuse." That's what we have been calling Sufficiency: what do we actually need? What is the least that will do the job? What is enough?

Principle 2 is to Reduce and Optimize, to "apply design approaches that minimise the quantity of new material required to deliver the desired function." This is what we have been calling Radical Simplicity: everything we build should be as simple as possible. Also:

Prioritise materials which are low or zero carbon, responsibly sourced, and which have low lifecycle impact in other areas, including the health of the occupant, as determined through a product specific environmental product declaration where available. Choose low or zero carbon construction techniques having maximum efficiency and minimum waste on site.

Principle 3 is to Plan for the future, designing for disassembly and deconstruction, and finally, Principle 4 is to offset. "As a last resort, offset residual embodied carbon emissions either within the project or organisational boundary or through verified offset schemes."

Different kinds of carbon

© World Green Building Council

The problem in convincing people about the problem of embodied carbon is that it has always been complicated by the calculations and the Life Cycle Analyses, and even calculating the Upfront Carbon Emissions can get complicated. But we all have to keep banging this drum. The WGBC notes:

Embodied carbon and the tools and methods needed to calculate it are relatively complex and new to many and the methods for addressing it are generally not well understood. By contrast, operational carbon and energy efficiency are more well established concepts with clear drivers and incentives for addressing them. Moreover, the false perception that embodied carbon is relatively insignificant compared to operational emissions over the lifecycle persists.

I am not sure it has to be so hard; manufacturers know what goes into their products.

All this results in a lack of market demand for low embodied carbon materials and construction methods and affects the perceived value of conducting LCA, meaning it may not be pursued at all due to cost and resourcing implications.

So forget about the LCA and just measure the UCE, the upfront emissions. Tell the manufacturers that you won't specify their products unless they tell you what the UCE are.

Stimulating demand will require a major shift in awareness across all parts of the value chain combined with concerted action to create market, fiscal policy and regulatory demand drivers and incentives.

This is a good time to start. It should be noted that, back at the Architecture of Emergency climate summit, some architects were far more radical, according to Dezeen:

"If you came here with the hope of one clear action for what you can do in the office tomorrow – stop it with the concrete," said Maria Smith, founder of architecture studio Interrobang..."If we invented concrete today, nobody would think it was a good idea," said Michael Ramage, an architectural engineer and University of Cambridge academic.

The World Green Building Council is perhaps a bit more realistic; concrete does make very nice foundations. They have also set tough but realistic deadlines. They have not been dogmatic. What they propose is achievable. And most critically, they are stressing the significance of Upfront Carbon in a way that I have not seen before. This is ground-breaking and important stuff.

Download and read the whole report here.