Feature image: The Lakeview West End Heights in Ithaca, New York. Photo copyright 2021 Tim Wilkes. The LEED City of Ithaca is committed to decarbonizing buildings.

Scientists have spelled out our collective climate challenge loud and clear: To prevent catastrophe, we must cut our global carbon emissions by at least 50% by 2030 in order to stay within the critical limit of 1.5 degrees of global warming.

“The whole planet has identified decarbonization as a priority,” says Anica Landreneau, chair of the LEED Steering Committee and global director of sustainable design and consulting at HOK. In the U.S., the White House and the U.S. Department of Energy (DOE) recently released a draft national definition for a zero-emissions building, intended to serve as a common framework for market alignment to move the building sector toward zero emissions.

Decarbonization has become a shorthand term for removing the production of greenhouse gases, predominantly carbon dioxide, from the global economy. To help as many organizations as possible to decarbonize as quickly as possible, USGBC has revamped its programs and initiatives including (but not limited to) LEED according to a newly released 2024–2026 strategic plan. These programs will enable a much broader swath of the building industry and related sectors to take immediate steps toward that goal—and thus have a much larger impact.

“There’s the entire built environment to consider, and all of it are pieces to the puzzle,” says Sean McMahon, vice president of product management at USGBC, who has spent the past year developing a program that supports building energy performance at the portfolio level. “While LEED has been our primary vehicle to advance the mission, there’s a lot of room for us to leverage the infrastructure, capacity and expertise that we’ve built as an organization over the last 30 years,” he says.

Focusing on existing buildings and operational carbon

LEED v5, currently under development, is the newest version of the LEED rating system. This version will prompt participants to curb carbon emissions in all possible ways. These include more obvious and less obvious methods, from going all-electric for heating and cooling systems to disposing of refrigerants in old HVAC systems safely.

“In LEED v5, we’ve laid out principles for the future of LEED, including decarbonizing fairly aggressively,” says Melissa Baker, senior vice president at USGBC. “We’ve addressed it for many years, but now it’s front and center.”

Scheduled to be released for public use next year, LEED v5 will continue to raise the bar and reward leadership in new buildings. For those who think that LEED is not an option for their type of project, it’s time to take another look. The draft for LEED for Operations and Maintenance (LEED O+M) came out first, and for good reason: The only way to meet the 2030 challenge set by the Paris Agreement is to tackle our existing buildings, which collectively account for 30% of global carbon emissions.

The path forward is clear. “There are two big steps: First, electrify your building—stop burning fossil fuel on site,” says Laurie Kerr, principal climate advisor at USGBC. “Second, buildings must reduce their peak heating and cooling loads, because that’s going to drive the size of the power grid.” Another reason to take action: There is also more financial help available. In the U.S., the recent $27 billion Greenhouse Gas Reduction Act unlocks funds for energy retrofits.

A modern glass building at twilight — The LEED Gold TCF Center in Detroit is certified under LEED v4.1 O+M. Photo credit: TCF Center.

Therefore, LEED v5 O+M is arriving at an opportune time. “This version has to work for owners of existing buildings,” says Landreneau. With the overarching goal of getting more buildings on the road to lower carbon, buildings will no longer have to meet certain performance standards, such as Energy Star or ASHRAE 62.2, right away.

Instead, building owners will be prompted to conduct assessments for their carbon trajectory, climate resilience and occupant needs. The rating system rewards energy performance and the development of a decarbonization plan by thinking through building energy usage and sources and installing energy monitors, among other steps.

To make sure that LEED v5 O+M fulfills its promise, USGBC is currently beta testing the draft rating system. The overarching philosophy is to keep things simple and provide clear guidance that allows an organization to take those initial steps without needing to hire specialty consultants.

While LEED v5 meets existing buildings where they are and pushes them ahead, it also provides a recipe for building them right the first time. LEED v5 for Building Design and Construction (BD+C) will likely require more advanced steps for decarbonization, particularly at the higher levels of certification, including electrification, load reduction, grid interoperability and carbon neutrality, says Andreneau.

LEED v5 O+M also introduces a prerequisite that requires safe management and disposal of legacy refrigerants and provides credit for meeting global warming potential (GWP) limits for new refrigerants, which are used in heating and cooling systems; many are potent greenhouse gases that can leak into the atmosphere without proper planning for safe disposal. LEED BD+C also incorporates GWP limits into the prerequisite.

Addressing the complexities of cutting embodied carbon

Of course, the carbon emissions generated by operating a building are only part of a building’s entire carbon footprint. LEED v5 addresses two other categories of carbon emissions: transportation emissions, produced by traveling to and from a building, and the embodied emissions of building materials such as concrete and steel, which require large amounts of energy to produce.

Cutting down embodied energy will have more weight in LEED v5 than it has in the past, with the introduction of an embodied carbon prerequisite into LEED BD+C and considerable emphasis on planning for circularity, existing building reuse and waste diversion in both LEED BD+C and LEED O+M.

An electric bus on a city street. — Cutting transportation emissions is another aspect of decarbonization. Left: An electric bus in LEED Gold Orange County, Florida. Right: Electric vehicle charging in LEED Gold Miami-Dade County.

An electric car charges in an underground parking garage. — Cutting transportation emissions is another aspect of decarbonization. Left: An electric bus in LEED Gold Orange County, Florida. Right: Electric vehicle charging in LEED Gold Miami-Dade County.

LEED v5 concentrates primarily on operational carbon, since that continues to be the largest source of a building’s emissions. “In America, operational carbon is roughly five times the amount of embodied carbon,” notes Kerr. “For now, operational carbon remains the dominant problem from the building side.”

However, LEED v5 gives embodied carbon in buildings, which constitutes 6% of U.S. total carbon emissions, the attention it deserves and prepares the ground for deeper cuts going forward. For building renovations, that means bonus points for reusing rather than buying new. “The credits will emphasize reuse of the most carbon-impactful products and materials, such as structural materials like concrete and steel, as well as finishes that have a lot of embodied carbon, like carpet,” says Wes Sullens, a LEED director at USGBC who focuses on materials and resources.

Whole building reuse, including office-to-housing conversions, will also get credit for heavy lifting. “You don’t have to build a new building from scratch to be eligible for LEED Gold or Platinum certification,” notes Landreneau. “You can take that existing building, focus on aspects such as decarbonization, resiliency, human health and well-being, and you can get that green building label.” Meanwhile, new buildings designed to reduce embodied carbon through a life cycle assessment will see a bump in points.

To address the carbon emissions that exist in a company’s supply chain (scope 3 emissions), LEED v5 will begin rewarding projects for specifying materials and finishes with less embodied carbon.

“We’ve been asking manufacturers to provide information about embodied carbon for the last 10 years, and now we know what the range is, so you can switch to those with less,” says Sullens. “The low-hanging fruit is to use lower-carbon-emissions concrete and steel with the highest percentage possible of recycled content—and, very importantly, not to overengineer your building to begin with.”

As previous versions of LEED have done, LEED v5 will continue to advance and promote a holistic approach to sustainability. “In terms of points, decarbonization accounts for about half, a quarter is human health, and another quarter is ecology and biodiversity,” says Landreneau. “Equity and resilience are a common throughline.”

A student works in a smaller area of a larger floor, framed by steel beams. — Steel saved from the partial demolition of an old mall was reused to frame collaboration areas for the Austin Community College Highland Phase II, and exposed concrete reduced the need for materials overall. Photo credit: Dror Baldinger.

Promoting accountability for entire building portfolios

How do you use market forces to accelerate decarbonization? Setting sustainability targets has become more pressing for the corporate world and governments with the rise of ESG reporting, now mandatory for those doing business in the European Union. In addition to financial disclosures, investment risk analysis and shareholder reports, many institutions have made declarations to become net zero. As a recent report from Net Zero Tracker has found, though, those ambitions often aren’t backed by a robust plan. To ensure accountability and results, there is a clear need for programs that track and verify legitimate progress toward decarbonization.

Leveraging their deep expertise in verifying sustainability achievements, USGBC and GBCI will unveil a new tool at Greenbuild 2024, which will take place in November in Philadelphia. It will provide an accurate measure of real estate portfolio performance, based on a well-defined set of metrics, including decarbonization.

“What’s missing from a lot of organizations’ commitments are the tangible steps and measurable improvements,” says Jeff Benavides, director of performance at scale and portfolios at USGBC. “We can help them quantify those and verify they are actually doing what they claim.”

Using this tool, corporations, government entities and nonprofit organizations alike can add substance to their action plans, create custom targets and verify portfolio-level performance. In the holistic spirit of LEED, it will track decarbonization along with a wide range of environmental and human impacts.

Many solutions working together to solve the decarbonization problem

Another program from USGBC is targeted at the financial sector. Investor Ready Energy Efficiency (IREE) provides third party verification that a potential energy efficiency retrofit of a commercial or multifamily building will indeed deliver the anticipated energy savings and carbon emission reductions. Banks and other investors can thus loan money for these kinds of projects with greater confidence, knowing that they will deliver substantial economic savings and cut carbon emissions.

By lowering risk and transaction costs, IREE is helping pave the way for greater investments in energy efficiency retrofits, which can cut energy usage by 40 percent or more and result in substantial long-term costs savings. The tool has already proven itself in the field: IREE is currently in use by Pacific Gas and Electric and by the Canadian government to evaluate potential projects for $3 billion in green loans.

Three people on the floor of a manufacturing facility hold up LEED certificates — The Colgate-Palmolive facility in Burlington, New Jersey, is the first project in the world to receive LEED Zero certification in all four categories: carbon, energy, water and waste. Photo credit: Marc Everett.

In 2018, USGBC introduced LEED Zero to address the carbon impact of buildings. This rating system certifies LEED buildings that have achieved net zero in at least one of four categories: energy, water, waste or carbon. It encourages projects to focus on operational carbon reduction and renewable energy use. An updated version of LEED Zero Carbon is available in draft alongside the LEED v5 O+M draft and beta. Requirements within this update specify no operational GHG emissions, to help the industry coalesce impactful strategies.

The LEED for Cities and Communities rating system tackles carbon reduction through many of its goals for sustainable urban development, infrastructure and transportation. Local governments are encouraged to adopt policies that promote energy efficiency, renewable energy and overall environmental sustainability; plus, the framework emphasizes community engagement and use of data to make the best decisions.

In addition, USGBC has other programs for specific industries that emphasize decarbonization along with biodiversity and ecosystem restoration, resilience and other desirable impacts, taking advantage of the unique levers that each industry offers. These include SITES for sustainable landscape projects, PEER for optimizing the efficiency and reliability of utility companies and power systems of all sizes, and TRUE, a certification program for zero waste achievements.

“There are the buildings, but then there’s the land that they sit on, the power systems that support them, and the materials and resources that go into and come out of the buildings,” says McMahon. “The suite of tools that we offer address the sustainability and decarbonization implications of all of those components.”

To that end, USGBC’s global community of members and volunteers is committed to improving not only LEED v5, but the entire toolkit. The overarching goal, as USGBC’s strategic plan states, is to “accelerate the role of buildings in decarbonizing economies and promoting equitable, healthy and resilient communities.” Adds McMahon: “We want to help everyone get on board now.”

Decarbonization: Proven solutions at greater speed and scale