Landscape architects are increasingly focused on decarbonizing design to reduce the carbon footprint of parks, plazas, and residential communities. According to Marieke Lacasse, FASLA, principal at GGLO, decarbonization is an essential part of the design process rather than a separate consideration. Lacasse highlighted practical strategies that landscape architects can implement to minimize the carbon footprint of their projects.
The carbon footprint of a landscape largely depends on the materials used, such as concrete, steel, and aluminum, which have high embodied carbon compared to materials like wood. To reduce climate impacts, designers can minimize hard surfaces and structures by incorporating more softscape, including trees, plants, and soils. Tools like Climate Positive Design’s Pathfinder can help landscape architects assess the carbon impacts of the materials they choose.
Climate Positive Design and the ASLA Field Guide to Climate Action recommend that 70% of landscapes be covered in softscape and 30% in hardscape. By reducing unnecessary concrete surfaces and using alternatives such as decomposed granite, local stone, or recycled materials, landscape architects can lower carbon emissions. Swapping conventional asphalt for pervious asphalt and reusing existing asphalt are also effective ways to reduce carbon-intensive materials.
In addition to reducing emissions, increasing carbon sequestration in landscapes is crucial for achieving climate positivity. Biodiverse landscapes with layers of trees and understory plants store more carbon. Despite the complexity of maximizing carbon storage, keeping existing trees and incorporating evergreen and deciduous trees can significantly contribute to carbon sequestration efforts.
A case study in Seattle demonstrated how design changes, such as using recycled materials and wood elements, can significantly reduce the time it takes for a landscape to become climate positive. Tools like Carbon Conscience, iTree, Tally, and the Embodied Carbon in Construction calculator enable landscape architects to measure and manage carbon in their projects effectively.
By prioritizing low-carbon materials and incorporating carbon considerations into their design workflow, landscape architecture firms can play a significant role in reducing emissions and mitigating the effects of climate change. It is essential for designers to focus on reducing emissions upfront, as sequestration occurs over time. Embracing decarbonization as an integral part of the design process can help create more sustainable and environmentally friendly landscapes.
