Green infrastructure: microclimatic effects for climate change adaptation and plant health in an urban warming scenario

Author(s)

Daniel Felipe Outa Yoshida

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Arquitetura e Urbanismo (FAU/SBI)
• Defense date: 2022-12-06

Examining board members

Denise Helena Silva Duarte; Maria Solange Gurgel de Castro Fontes; Humberto Ribeiro da Rocha

• Advisor: Denise Helena Silva Duarte

Abstract

Climate change is accompanied by rising temperatures and increasing frequency and intensity of heat waves, phenomena that are amplified in urban areas. Due to the microclimatic potential of green infrastructure, it becomes an important strategy for climate change adaptation in cities. Therefore, this research quantifies the effects of green infrastructure on urban microclimate under current climate conditions and future climate projections in the city of São Paulo, answering the following questions: 1) Based on the urban and climate context of the city of São Paulo, what are the microclimatic effects of green infrastructure in the city, under current and future climate? 2) How will green infrastructure react to increasing temperatures, from the point of view of plant health, and what are the impacts on their microclimatic effects? To this end, this work uses the Local Climate Zones - LCZ classification for urban morphology, some microclimatic and vegetation parameters collected in the field, the future climate projections of IPCC AR5 / RCP 8.5 of the PROJETA/INPE platform and the high-resolution microclimate model ENVI-met V5, to simulate the microclimatic effects of vegetation in different scenarios and also the vitality of plants. The green infrastructure utilized in the simulations are street trees. Overall, for LCZ 3, 6 and 8, the most commonly found in São Paulo, at the hottest times of the day vegetation reduced air temperature by up to 0.72°C in the current climate, up to 0.5°C in the future climate 2079-2099, with virtually no reduction on the most extreme heat day in November 2099. At the same time, vegetation reduced the mean radiant temperature by up to 14°C in the current climate and up to 8°C in future climate projections; surface temperature was also reduced by up to 14°C in the current climate and up to 13°C in future projections. In all simulations the comfort indices PET and TEP reach thermal discomfort levels of warm and very warm, and can reach very high thermal sensations, 60°C for PET and close to that in TEP, within the worst-case climate scenario. However, the presence of vegetation in the simulations reduced the PET and TEP values, on average, by 5°C in the current climate, by 4.5°C in the future climate 2079-2099, and by 2.5°C on the most extreme heat day in November 2099. There was a change in thermal sensation from very hot to hot within TEP with the presence of vegetation in the current scenario. As an indicator of plant health in the face of urban warming, leaf temperature averaged 28°C in the current climate, 31°C in the future climate 2079-2099, and up to 48°C on the most extreme heat day, suggesting, in the latter case, cessation of evapotranspiration and the risk of irreversible damage to vegetation. In view of the results, it is evident that vegetation reduces heating and improves the feeling of urban thermal comfort, especially diurnal; however, there are limitations on the microclimatic effects of vegetation, especially when it is subjected to high temperatures. (AU)

• FAPESP's process: 20/01610-0 - Green infrastructure: microclimate effects to climate adaptation and plant health in an urban warming scenario
• Grantee: Daniel Felipe Outa Yoshida
• Support Opportunities: Scholarships in Brazil - Master