Investigating green roofs' CO2 sequestration with cold- and drought-tolerant plants (a short- and long-term carbon footprint view).

Mohammad Reza Seyedabadi,Jafar Nabati,Mohsen Karrabi

doi:10.1007/s11356-021-16750-w

Mohammad Reza Seyedabadi, Jafar Nabati + Show 1 more

Open Access

https://doi.org/10.1007/s11356-021-16750-w

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Abstract

In recent years, green roofs have become the subject of increasing interest because of their good aesthetic qualities, energy conservation, and ability to reduce thermal island effect and absorb greenhouse gases, especially carbon dioxide (CO2). Given the typically significant carbon emission of construction activities, adding any extra component to a structure increases the amount of carbon to be released during the execution stage. This also applies to green roofs, which require more materials and more extensive construction activities than traditional roofs. However, plants of green roofs absorb substantial amounts of CO2 during their lifetime, thus leaving both short- and long-term positive impacts on the building's carbon footprint. This study investigated the short- and long-term effects of green roofs on carbon footprint, as compared to conventional roofs. For this investigation, the CO2 uptake of eight plant species with suitable drought- and cold-resistant properties was measured by infrared gas analysis (IRGA), and the effect of green roof on the building's carbon footprint was analyzed using the software Design Builder. The results showed that building a green roof instead of a traditional roof increases the carbon emission of the construction process by 4.6 kg/m2 of roof area. Investigations showed that, under high light intensities (1500-2000 μmol/m2 s), Sedum acre L. has the best performance in compensating the extra carbon emission imposed on the construction process (in 264 days only). Under low light intensities (1000-1500 μmol/m2 s), Frankenia laevis showed the best increase in the amount of carbon uptake (2.27 kg/m2 year).

Highlights

With the continued use of fossil fuels in numerous industries and vehicles, there is a clear view of the impact of greenhouse gas emissions on the acceleration of climate change, as this phenomenon is having undeniable effects on the environment, society, and economy (González and Navarro 2006)
The results show that plant species Sedum acre L, Sedum spectabile boreau, Frankenia laevis, and Vinca major have higher CO2 uptake rates than the others and a higher potential to offset the extra carbon produced during the construction of the green roof
This study intends to investigate the CO2 uptake of eight plant species namely Sedum acre L, Sedum spectabile boreau, Frankenia laevis, Vinca major, Phyla nodiflora, Potentilla reptans, Aptenia cordifolia and Carpobrotus edulis when used as green roof vegetation and determine the time it takes for the roof to offset the extra carbon produced during the construction process for each case

Summary

Introduction

With the continued use of fossil fuels in numerous industries and vehicles, there is a clear view of the impact of greenhouse gas emissions on the acceleration of climate change, as this phenomenon is having undeniable effects on the environment, society, and economy (González and Navarro 2006). The building sector accounts for roughly 30% of the global CO2 emission, and should, be given a high priority in the efforts to devise and develop sustainable solutions to reach an acceptable level of carbon emission (Jeong et al 2012). One of these efforts is to promote the use of building materials with low environmental impacts. Given the ability of green roofs to reduce the energy consumption of buildings, the effective use of this structural element can be very helpful in decreasing the buildings’ overall carbon footprint. The vegetation of these roofs can absorb CO2 by photosynthesis, thereby reducing the amount of carbon released to the atmosphere

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