Annotation 1.
Hoffman, Jeremy S., et al. “The Effects of Historical Housing Policies on Resident Exposure to Intra-Urban Heat: A Study of 108 US Urban Areas.” Climate, vol. 8, no. 1, Jan. 2020, p. 12. Crossref, https://doi.org/10.3390/cli8010012.
Researchers from Portland State University Hoffman, Shandas, and Pendleton explore the relationship between historical housing policies, particularly “redlining,” and current disparities in exposure to urban heat. Their study analyzes Landsat-derived land surface temperatures and found a consistent pattern across 108 U.S. urban areas, with areas previously redlined experiencing higher temperatures than their non-redlined counterparts by up to 7°C. The study suggests that historical housing policies have a lingering effect on current urban heat exposure, exacerbating the urban heat island effect in specific neighborhoods, often those inhabited by marginalized communities.
Hoffman et al offer a compelling quantitative analysis linking historical policy decisions to present-day environmental challenges, aligning with growing concerns over environmental inequities. The comprehensive analysis of multiple U.S. cities offers a broader context, which can be instrumental in understanding and addressing San Francisco's unique challenges within this national phenomenon.
I plan to utilize this study to showcase how urban heat islands disproportionately affect marginalized communities and use it as a starting point to further investigate this relationship within San Francisco. This will be an invaluable resource for my website’s “Disproportionate Risk” page, where I may include some of the graphics in this study that show the difference in surface temperature in historically redlined and non-redlined areas – these graphics will be key to catching the attention of website visitors and stress the nature of current climate inequity. Similarly, I plan to utilize this study to justify the need for better public urban design, such as building plans that include significantly more green spaces.
Annotation 2.
Wang, Xun, et al. "The effectiveness of cool and green roofs in mitigating urban heat island and improving human thermal comfort." Building and Environment 217 (2022): 109082.
This 2022 study by Xun Wang, Huidong Li, and Sahar Sodoudi, examines the impact of cool and green roofs on mitigating the urban heat island (UHI) effect and improving human thermal comfort in urban settings. The study contributes significant insights into urban planning and climate mitigation strategies, especially relevant for densely populated cities. Key findings include that cool roofs, especially those with high albedo, are more effective than green roofs in reducing urban temperatures, particularly at night, but that both strategies lead to reductions in mean radiant temperature and wind speed, and an increase in relative humidity. Notably, when green and cool roofs are implemented, the duration of strong heat stress is reduced from 7 hours to 5 hours.
This study provides empirical evidence on the effectiveness of urban cooling strategies, which could inform recommendations for policy and design interventions in San Francisco. In addition to green and cool roofs, I plan to explore more urban design strategies to combat urban heat islands, but the detailed analysis of cool and green roofs' performance under various conditions will be instrumental in shaping the content and recommendations on my website.
In my website’s “Urban Design Solutions” section, I plan to highlight various sustainable design strategies to mitigate the urban heat island effect and compare the benefits and downsides of implementing different types of strategies. While this study only compares green and cool roofs, I would similarly like to explore how different strategies like living walls or grid-like vegetation and pavement systems can reduce rising temperatures and urban heat islands. I would also like to connect the study’s findings on the reduction in heat stress duration to my findings on inequity in the “Disproportionate Risk” page – showcasing that there are solutions that can be implemented to address climate-change induced inequities.
Annotation 3.
Huang, Kangning, et al. "Projecting global urban land expansion and heat island intensification through 2050." Environmental Research Letters 14.11 (2019): 114037.
Huang, Li, Liu and Seto present a comprehensive study on the global trends of urban land expansion and the intensification of urban heat islands up to 2050. They utilize advanced modeling techniques to predict the spatial and temporal patterns of urban growth and their impact on urban heat islands, emphasizing the dual influence of urban land changes and greenhouse gas emissions. They found that the urban heat island effect could cause extra warming in cities and is largely the result of less evapotranspiration. In particular, they estimated that the effect will contribute to half the warming caused by climate change by 2050, meaning a 2-degree increase in temperature from climate change would compound with an extra 1 degree of warming from the urban heat island effect.
I plan to utilize this study in my “Urban Heat Islands Effect” page to provide greater context for how climate change and urban heat islands interact with each other. Additionally, this study will be invaluable in stressing the importance of an urgent response to mitigate the effects of urban heat islands on a growing population. I plan to narrow this larger relationship between anthropogenic climate change and urban heat islands to San Francisco and highlight how San Francisco’s unique site will experience significantly greater ambient temperatures as a result of climate change. This will motivate site visitors to be more supportive of solutions outlined in my “Urban Design Solutions” page.