The Underappreciated Benefits of “Green” Urban Brownfields

by Dan McCabe

Sustainable urban planning aims to ensure that urban development patterns do as little ecological harm as possible, but new research suggests that conventional planning approaches neglect a significant contributor to urban environmental health. Mathey et al. (2015) studied the effects of urban brownfields, formerly developed sites that have been abandoned and remain underused, and found that vegetation-rich “green” brownfields provide a variety of valuable ecological services to their areas. The benefits of these services depend on the type and amount of vegetation at a particular site, its location, and human intervention, but green urban brownfields overall show a large potential to aid the goals of sustainable development. Specifically, brownfields provide habitats that support enhanced biological diversity, aid microclimate by cooling the unnaturally warm urban environment, and provide local residents with recreational opportunities. These findings were obtained via a literature review, climate modeling, and a survey of local residents. The authors concluded that green urban brownfields should receive more credit for their ecosystem services and the most effective way to reap their benefits is to leave them mostly wild, while possibly converting some area to recreational spaces. Continue reading

The Power of Green Space for Reducing Surface Temperature in Tel Aviv, Israel

by Dan McCabe

One key objective of sustainable urban planning is to limit the urban heat island (UHI) effect, the increased local temperature in highly built areas due to differences from the natural environment in the absorption and reflection of solar energy at the surface. Previous research has displayed the value of large urban parks in controlling temperature in cities, but less is known about the effect of smaller green spaces. In order to investigate how vegetation and construction levels impact UHI severity, Rotem-Mindali et al. (2015) used ten years of remotely sensed data from two NASA satellites to analyze the relationship between different land uses and land surface temperature (LST) in Tel Aviv, Israel. The authors compiled information on local LST and Normalized Difference Vegetation Index (NDVI), a measure of vegetation cover, and used it to search for a correlation between land use type and mean surface temperature for summer nights. In their analysis, they found an enormous difference of 13°C in mean temperature among different locations in Tel Aviv. There was a strong correlation between land use type and LST, with the most vegetated regions experiencing much lower average temperatures than highly built regions. Continue reading

The Anthropogenic Roots of Increased Flooding in Kano, Nigeria

by Dan McCabe

Intelligent planning for urban development requires an understanding of how different development paths can impact sustainability. In order to better understand what aspects of cities impact sustainability, Barau et al. (2015) investigated historical trends in the environmental resilience of Kano, Nigeria. Kano, northern Nigeria’s largest city with a population of over 2 million, has been a commercial center since the 10th century and has experienced extreme morphological changes in the centuries since then. Recently, the city has been subject to an increasing number of catastrophic flooding events that have caused deaths, exacerbated the spread of infectious diseases, and forced the relocation of hundreds of thousands of residents. As the frequency of extreme weather threatens to increase due to global climate change, Kano’s ability to respond to flooding is of great concern. Barau et al. therefore sought to determine how the city’s evolution has made it especially prone to severe floods. Continue reading