20 Years On: The California Academy of Sciences Green Roof
This story is adapted from a presentation given by Senior Research Associate Jonah Susskind as part of the Landscape Architecture Foundation’s (LAF) Case Study Investigation (CSI) program. Jonah served as the firm liaison for the project, working with the University of California, Berkeley’s Gustavo Coronilla, Matt Roberts, and Nate Kauffman. Watch the full presentation here, starting at 36:23. View the case study brief from LAF here.
The California Academy of Sciences green roof carbon-performance study is an XL Lab project. It is the firm’s seventh partnered study with LAF and an academic team.
In recent years, “biophilia” has become such a popular catch-all term in architecture that it approaches cliché, but what does it really mean? For many, it may be a broad gesture at sustainability and well-being—we’ve all seen the Pinterest-worthy renderings of glassy facades uniformly blanketed with vines and mature trees hoisted into the sky; corporate interiors shrouded in cascading tropical gardens; macro features and micro details lifted directly from nature’s playbook. In fewer instances, it may be a deeply investigated design ethos, shaping both the form and function of buildings. Either way, and regardless of actual versus promised impact, it’s hard to deny the upward tick in so-called “living buildings” and ecologically-inspired design over the past two decades. For landscape architects, the word is almost redundant; nature is both our palette and product.
The California Academy of Sciences, whose current home within Golden Gate Park was completed by Renzo Piano Building Workshop (RPBW) in 2008, may be a rare example of biophilic architecture in service of landscape rather than vice versa. Inspired by the undulating hills that give San Francisco its famous slopes and Bay views, the redesigned Academy is housed beneath a 2.5-acre green roof that is the building’s defining feature, giving form to seven sculpted hills and four domes, one of which hosts a four-story rainforest exhibit, another containing a planetarium. Throughout its extent, the roof supports over half a million native California plants—a living laboratory that changes with the seasons and years.
Background
The Academy had several previous lodgings. In 1906, the Great San Francisco Earthquake destroyed nearly 80% of the city, including the original William W. Thayer-designed building on Market Street. Relocated soon after into the newly opened Golden Gate Park, the Beaux-Arts building for the Academy by Lewis P. Hobart was damaged, yet again, in the 1989 Loma Prieta Earthquake.
Seeking a fortified building that could accommodate the institution’s evolving needs alongside modern seismic safety standards, a RPBW-led team was selected to consolidate its various functions under a single roof. As the green roof-centric approach came into form in the early 2000s, SWA collaborated with RANA Creek to lead the technically complex landscape strategy underpinning the design. Today, the roof is an attraction unto itself, able to host 200 visitors on a 3,500-square-foot observation deck. In 2023 alone, over 540,000 individuals passed through the museum, 49% of whom visited the roof.
A blueprint for living buildings
Nearly two decades after completion, the California Academy of Sciences is still an iconic example of green roof design, serving as a reference for countless projects across the globe. In response to a challenging design brief—a contiguous landscape with grading up to 60%—SWA created a full-scale mock-up to test the anchoring system, multilayered soil drainage, gabion channels, and coconut-husk planting trays that would decompose upon installation. At the time, strategies to reduce embodied carbon (even the very phrase) were not widely popularized in A/E/C, yet the design was an early adopter of these techniques, setting the stage for future efforts.
Installed with over 50,000 trays, the roof accommodates more than 70% California native plants that, in turn, support over 36 species of pollinators and insects. The research team studied the carbon capture performance of different species, weighing them in terms of efficacy: first was grasslands, making up the largest area; then herbaceous and woody species in smaller clusters. Altogether, the roof’s plant matter locks in 450 kg of carbon, equivalent to the emissions from a one-way drive from San Francisco to Aspen, Colorado.
Thermal performance
Beyond carbon capture, the roof also reduces the energy demands of the building at large, playing a key role in its 2008 certification as the first-ever double LEED platinum building in the world. Astonishingly, the building also self-regulates in temperature—skylights across the roof are outfitted with heat sensors that open to the air when the interior needs to cool down.
As part of initial studies, the team also compared the design’s performance to an irrigated lawn in Golden Gate Park and the neighboring Children’s Museum. Using thermal imaging cameras to test the green roof versus open lawns, the group monitored the sites multiple times a day, gathering data on sun exposure and shading. Between the three, the green roof had the lowest average temperature by over 12 degrees, due in part to the topography creating sheltered microclimates. Today, it reduces overall temperatures by up to 18 degrees.
Looking ahead
Since 2013, SWA has conducted formal post-occupancy studies to ensure high-performance outcomes in the field. The firm’s Climate Action Plan, published in 2024, commits to reducing project emissions by 50% by 2030. Projects like the California Academy of Sciences green roof serve as important landmarks in the firm’s portfolio of carbon-conscious designs, providing guidelines for future work, including the Giant Interactive Headquarters in Shanghai. Additionally, this study furthers SWA’s efforts in research-informed design, ensuring long-term performance in our projects.