Your Green Building Has a Carbon Problem

The designers of the “Sustainability Pavilion” at the heart of Expo 2020 Dubai described their brainchild as the embodiment of a low-carbon future. The structure’s vast oval canopy was fitted with photovoltaic panels designed to harvest the desert sun. Eighteen “energy trees” rose around the building, providing shade and capturing solar power. A water management system collected condensation from the air and mixed it with water desalinated onsite to provide potable water. Inside, visitors were invited to consider how their everyday choices shape environmental impact.

Yet for sustainability consultant Simon Sturgis, the most important emissions associated with the building were the ones visitors could not see. Based on his own calculations, Sturgis estimated that the carbon released through the pavilion's construction—from the extraction and manufacture of its materials to their transport and assembly—may have exceeded 18,000 tons, roughly twice the level he would consider appropriate for a building of its size.

"People's intentions are good," Sturgis told tBE in an interview. "I suspect they probably did the best they could at the time. This is a journey and we are all learning."

Whether or not his estimate proves precise, it points to a growing challenge for the building industry. For decades, efforts to make buildings more sustainable have focused primarily on reducing the energy they consume once occupied. But as electricity grids decarbonize and energy-efficiency standards tighten, attention is increasingly shifting to embodied carbon—the emissions associated with extracting raw materials, manufacturing building products, transporting them to site, constructing buildings, and eventually demolishing them. According to the World Green Building Council, upfront embodied carbon will account for roughly half of the total carbon footprint of new construction between now and 2050.

Despite its growing importance, embodied carbon remains difficult to address. Part of the challenge is technical: calculating it requires emissions data that spans complex global supply chains and thousands of individual building components. Part of it is institutional: the certification systems that have come to define sustainable architecture were largely developed around operational energy use rather than material consumption. And part of it is cultural: The building features most commonly associated with sustainable design—solar canopies, living walls, tree-covered towers—are highly visible, while the emissions embedded in concrete, steel, foundations, and structural systems are largely hidden from view.

The consequences are significant. Roughly 10.5% of global greenhouse gas emissions stem from the production of cement and steel, meaning a great deal of a building’s carbon footprint is established before a single light is switched on. Researchers and sustainability experts increasingly warn that without addressing these upfront emissions, even highly energy-efficient buildings will continue to carry a substantial environmental cost.

"When you examine embodied carbon, you're looking at the efficiency with which we use materials," Sturgis said. "To build buildings, we're pulling huge quantities of resources from the surface of the planet. We can't do that forever."

The Measurement Problem

One of the central challenges of reducing embodied carbon is figuring out how to measure it. Unlike operational carbon, which can be quantified using energy meters and standardized calculations, embodied carbon requires a comprehensive accounting of emissions embedded across an entire supply chain, from material extraction and manufacturing to transport, construction, maintenance, and eventual demolition. As of yet, the AEC industry lacks a widely-accepted methodology for calculating embodied carbon, making its use limited and implementation uneven.

Even defining the boundaries of such an analysis is contested. Embodied carbon can be calculated across multiple stages, from cradle-to-gate (material production only) to cradle-to-grave (including demolition and disposal). In practice, many assessments omit key stages such as construction site activity or end-of-life processing. These omissions can significantly alter the final carbon tally.

One of the reasons for these omissions is data availability. Many assessments rely heavily on industry averages rather than product-specific Environmental Product Declarations (EPDs), introducing further uncertainty. A 2025 case study by Stanford University researchers Giulia Scagliotti and Martin Fischer found that only about 20% of a building’s embodied carbon is typically calculated using product-specific data, while the remaining 80% depends on generalized databases. Even basic quantities are often incomplete: just 11% of material data in their study was extracted directly from Building Information Models (BIM), with the rest assembled from 2D drawings and fragmented sources.

This dearth of data limits the ability for policy interventions to strengthen building codes and ultimately decarbonize the AEC sector. As researchers wrote in a 2021 study examining the use of embodied carbon calculations in the U.S. construction industry, “[I]t is unclear whether we have adequate knowledge infrastructure to incorporate embodied carbon into national model codes.”

Some within the industry have begun developing standardized frameworks aimed at making carbon accounting more consistent and actionable. Among them is the RICS Professional Statement: Whole Life Carbon Assessment for the Built Environment, first published in 2017 and substantially expanded in 2023. Developed by a team led by Sturgis, the framework provides a detailed methodology for calculating both embodied and operational emissions—what practitioners refer to as “whole life carbon.”

RICS offers “a methodology so that anybody designing a building can assess and calculate the amount of carbon in it,” Sturgis said. The updated 2023 edition, which expanded the first edition from roughly 30 pages to more than 200, reflects both the increasing sophistication of carbon accounting and the urgency of its standardization.

According to Sturgis, the framework is now widely used in the UK and increasingly adopted internationally, including by major firms working on large-scale urban projects. Crucially, it applies not only to new construction, but also to refurbishment and infrastructure—areas where emissions reductions can be significant.

Sturgis emphasized that the point is not simply better measurement, but a shift in how the industry understands its role in curbing climate change. “Embodied is half the picture; operational is the other half,” he said. “If you don’t measure both, you don’t understand the total impact.”

Maintaining green landscapes in arid and semi-arid climates requires vast inputs of water, often supplied artificially rather than through rainfall. A 2021 study published in Energies by researchers at the University of Lisbon and the Instituto Superior Técnico found that irrigation is the dominant component of water consumption in urban green spaces, particularly in water-scarce contexts, where green areas are often maintained through substantial artificial watering regimes.

In arid environments, such water use is not only resource-intensive but also linked to greenhouse gas emissions. Across many cities in the Middle East and Gulf region, water is supplied through long-distance pumping, deep groundwater extraction, and, increasingly, through energy-intensive desalination plants.

According to a 2020 peer-reviewed review in Sustainability, desalinating 1,000 cubic meters of water can consume the equivalent of about 37 barrels of oil and produce roughly 10 tons of carbon dioxide emissions. The same study notes that in the Middle East, the growing reliance on desalination is expected to significantly increase energy demand, with the water sector’s share of total electricity consumption projected to rise to 16 percent by 2040, up from 9 percent in 2015.

In the Gulf states in particular, desalination is a major component of electricity demand and is structurally integrated into national energy systems, reinforcing the interdependence between water supply and fossil fuel based power generation. As a result, irrigated urban “greening” is embedded within infrastructure systems that carry significant indirect emissions.

It’s also worth considering the volume of water that urban greening can demand. A 2023 study in Sustainability examining urban green spaces in Chinese cities found that irrigated landscapes can account for more than 20 percent of residential water use.

While these green spaces can reduce urban temperatures by around 1 to 2 degrees Celsius, they achieve this through constant water and energy inputs rather than natural adaptation, showing the high resource cost behind what is often presented as “natural” urban cooling.

As landscape architect Gareth Doherty argues in his book Paradoxes of Green, the reliance on resource-intensive systems to sustain visibly “green” environments produces the veneer of sustainability, while depending on continuous resource inputs to remain viable.

As such, the color green becomes not a neutral marker of ecological virtue, but a culturally and historically specific ideal — one that does not translate easily across the globe.

The Visibility Problem

Embodied carbon is not only difficult to calculate, but difficult to see.

For decades, the image of sustainable architecture has been shaped by features like rooftop solar panels, green walls, planted terraces, rainwater harvesting systems, and lush landscaping. These elements signal environmental responsibility in a way that concrete mixes, structural optimization, and material efficiency cannot. As researchers have begun paying closer attention to embodied carbon, some have argued that sustainable design remains disproportionately focused on visible environmental features, while the emissions embedded in materials, structures, and infrastructure often receive less scrutiny.

This tension is particularly apparent in projects such as Milan's Bosco Verticale, whose tree-covered balconies have become one of the most recognizable symbols of sustainable architecture globally. Widely celebrated for bringing vegetation into a dense urban environment, the towers also demonstrate a reality that embodied-carbon researchers have increasingly sought to quantify, namely that environmental features often require additional materials, engineering, and carbon-intensive infrastructure.

“To support the extensive planters that house the ‘green facade’, the architects designed cantilevered concrete terraces to sustain the added weight of the vegetation,” wrote researchers at the World Green Building Council. “This meant that additional building materials were used in its construction and therefore added to the embodied emissions and natural resources required to achieve the benefits [of the design].”

The certification problem

Green building certification systems contribute to the industry’s failure to account for construction-related carbon emissions. The dominant frameworks used to define “sustainable” buildings—most notably the Leadership in Energy and Environmental Design (LEED) certification system and its European counterpart, BREEAM—were developed in an earlier era of environmental thinking, when operational energy use was the primary concern. According to civil engineer and researcher Ali Amiri, they continue to reflect that legacy.

“People considered a building as green if it used less energy and water,” Amiri told tBE in an interview. For years, this emphasis drove meaningful improvements in efficiency. But it also created a blind spot. “We realized that we are making buildings energy efficient, but at the same time we [were continuing to] use extra material in construction,” he said.

That tradeoff is now central to the critique of certification systems. In a Life Cycle Assessment (LCA) study co-authored by Amiri, different structural scenarios—including concrete, hybrid concrete-wood, and timber buildings—were compared for their embodied emissions. Timber construction showed the lowest overall environmental impact. Yet within the LEED framework, only a small portion of that difference was captured: of 110 available points, just three were directly tied to embodied emissions related to material selection.

The result is a system that rewards buildings for reducing operational energy while overlooking the carbon cost of the materials required to achieve those reductions. In some cases, Amiri said, this opens the door to a form of greenwashing, since lower levels of certification can be achieved without meaningful reductions in total life-cycle emissions. This allows firms to market their projects as sustainable while their embodied carbon remains largely unaddressed.

At higher certification levels, such as LEED Gold or Platinum, this becomes more difficult—but not impossible. The structure of the system still allows project teams to accumulate points across a wide range of categories, often prioritizing easier or more familiar credits over more complex forms of analysis. As Amiri noted, certification also carries clear market value: it is “a brand you can put on your website,” one that can increase a building’s appeal to buyers and tenants.

For Simon Sturgis, this points to the need to incorporate vetted carbon counting systems like RICS into rating systems like LEED.

“LEED doesn’t give you a detailed methodology for calculating the carbon in a steel frame,” he said. “It’s more generic.” Frameworks like the RICS standard, by contrast, are designed to produce consistent, comparable carbon calculations. In practice, he added, the two should be seen as complementary: methodologies establish the numbers, while certification systems set targets for them.

Rewriting the rules of building

Several countries are now moving to translate embodied-carbon accounting into enforceable standards. In the UK, emerging net-zero building frameworks propose progressively stricter limits on whole-life carbon emissions per square meter. Under such systems, methodologies such as RICS would be used to calculate a building's carbon footprint, while regulatory and certification frameworks would determine whether it meets the required thresholds.

Recent updates to LEED suggest that a similar shift may be underway within the certification landscape. The latest version, LEED v5, places greater emphasis on whole-life carbon, incorporating credits for whole-building Life Cycle Assessment, Environmental Product Declarations, and material reuse strategies.

“I think they are moving forward,” Amiri said, noting that embodied emissions are now more clearly acknowledged within the system.

Yet even with these improvements, the broader challenge remains: reducing emissions is not only a matter of better accounting, but of using fewer resources in the first place.

This requires rethinking how buildings are designed at a fundamental level: using mechanical connections instead of adhesives to allow disassembly, using optimization algorithms to produce efficient building designs, and rethinking sustainable design away from visual spectacle toward material reduction. It also means confronting a larger systemic issue: global demand for construction materials continues to rise, driven by urbanization and new development, even in regions with stable populations.

Both Amiri and Sturgis point toward the same conclusion. Better measurement is essential, but it is not sufficient. Without frameworks that prioritize whole-life carbon—and without a broader shift toward reusing and reducing materials—the construction industry will struggle to align with climate targets.

The question is no longer whether buildings are energy efficient. It is whether the systems used to define sustainability are capable of accounting for the full cost of construction.