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LEVERAGING EXISTING AND HISTORIC BUILDINGS FOR CLIMATE ACTION by Stevens Krug, AIA, PE, LEED AP, AEE Fellow; Lori Ferriss, AIA, PE, LEED AP BD+C; Channing Swanson, AIA; & Michael Ingui, AIA, NCARB, Certified Passive House Designer
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xamples of reuse of historical elements and adaptive reuse can be found throughout history. Using appropriate physical assets created by previous generations is important to reducing greenhouse gas emissions. In this article, the complexities of renovations and reuse will be covered, helpful strategies and opportunities will be identified. First, we will discuss some truths about climate change. We will describe why the reuse of the existing building stock is one of the most effective tools we have in addressing GHG emissions in the environment. Next, two case studies will show how architects can address climate change through adaptive reuse and green energy retrofits. First, we will illustrate how an adaptive reuse project can anchor urban revitalization and redevelopment through sustainable design. Then we will describe an approach to address historic masonry Passive House retrofits, which you can apply to all kinds of masonry buildings.
EXISTING BUILDINGS AS AN ASSET IN CLIMATE ACTION We have created a climate emergency. To have the greatest chance staying below 1.5 degrees Celsius, the ambitious target suggested by the Paris Agreement, emissions must be reduced by 65% by 2030 and to net zero by 2040. Thus, there is a time value to carbon emissions; to reduce the rate of emissions dramatically and quickly, carbon mitigation strategies that
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yield immediate reductions are more valuable than those that take years. This is where existing buildings enter as a key asset in climate action. Globally, 37% of greenhouse gas emissions come from buildings. Of that, roughly two thirds of emissions come from operation of existing buildings; the rest represent embodied emissions from construction and manufacturing of buildings. In urban centers like New York City, buildings’ contribution is much higher, frequently around 70%. These numbers reveal a tremendous opportunity for climate action in our existing built environment—by reusing and upgrading buildings, we can drive down and decarbonize building operations with minimal upfront, embodied carbon. According to the Zero Net Carbon Collaboration for Existing and Historic Buildings, renovating a building can yield as much as a 75%-80% reduction in embodied carbon compared to replacing it with standard new construction, supporting the need for near-term carbon reductions. Case studies have shown that even if new construction can achieve higher levels of energy efficiency, it can take decades, frequently well beyond 2030 or even 2050, for the higher embodied carbon investment of new construction to pay back through energy savings. Additionally, building reuse, conservation, salvage, and deconstruction offer co-benefits like support of local economic growth, preservation of cultural heritage, and strengthening of community.
