Poorer Urban Areas Suffer Worse Heat:

A recent study in New York community districts and United Hospital Fund neighbourhoods shows that there is a higher rate of heat-related mortality in poorer areas.

According to an article in the Harvard Gazette, there were higher heat related deaths in southern and western Bronx, central Brooklyn, northern Manhattan, and the eastern side of midtown.

The poorer residents mainly occupy these smaller heat islands. The study showed a strong correlation between excess deaths and poverty, poor housing quality, hypertension, and impervious land cover.

“It is known that there is an unequal distribution of risk from climate change around the world,” Joyce Klein Rosenthal, an assistance professor of urban design, told the Gazette. “What’s less known is that there is a significant variability of risks from climate change and extreme events within American cities, related to poverty and conditions in the built environment.”

She added that it is very important to recognise that “designers, architects, and urban planners have the capacity and agency to improve urban conditions”. Rosenthal said that by understanding vulnerability within cities, there is a better chance to implement more “effective adaptive strategies with communities”.

Several cities have already started ways to ease the heat for the most vulnerable of residents through “longstanding programs to distribute fans and air-conditioners and open cooling centres on the hottest days”.

“Studies like this provide health outcome-related evidence supporting adaptive interventions. We have health disparities in the spatial distribution of excess mortality of seniors during heat events. The types of characteristics we found to be associated [with that mortality] are within the collective ability of municipalities to intervene,” Rosenthal told the Gazette.

She said that heat, like ground-level ozone, is an environmental stressor, “unevenly distributed in places where there are less trees, less green space, and associated with poorer housing quality”.

According to the study, income levels are associated with surface temperatures. It showed that poorer neighbourhoods are hotter while wealthier neighbourhoods are cooler.

“Urban design strategies can make a difference in reducing urban micro-heat islands,” Rosenthal said.

She added that if the aging population, hotter climate, and lack of affordable housing are not addressed, it may constitute a “perfect storm for future heat wave deaths”.

Rosenthal said the study proves that greening a neighbourhood should be taken seriously. “The disciplines of the built environment – urban planning, architecture, landscape architecture, and urban design – have the knowledge and responsibility to make a difference.”

Nature Trails Detrimental to Urban Forests:

Being close to nature has its downside that is detrimental to the environment, according to a latest study by scientists from Curtin University and Griffith University.

Remnant urban forests are popular sites for recreational activities like hiking, biking, and motorised recreation. However, the study said this could result in the “formation of extensive trail networks, fragmenting vegetation into patches separated by modified edge effects and ultimately contributing to the degradation of the ecosystem as a whole”.

The study used a Geographic Information System (GIS) approach to assess the extent and diversity of trail-based fragmentation across 17 remnants of endangered urban forest in southeast Queensland, Australia (a total area of 829 hectares).

The study mapped out 14 different trail types totaling 46.1km of informal biking and hiking. More than 47 hectares or 5.7 percent of forest have been lost to trails and their edge effect, nearly equal to the area recently cleared for urban development.

“The degree of fragmentation in some remnants was in the same order of magnitude as found for some of the most popular nature-based recreation sites in the world. In localised areas, the fragmentation was particularly severe as a result of wide trails used by motorised recreation, but these trails were generally uncommon across the landscape (five percent). Spatial regression revealed that the number of access points per remnant was positively correlated with the degree of fragmentation,” the study said.

An article by Science Network Western Australia said experts from both universities and co-authors, Mark Ballantyne, Dr Ori Gudes and Professor Catherine Pickering, found these forest area trails result in changes to soil microbiology, compaction, erosion, the introduction of weeds and pathogens and wildlife disturbance.

“[All trail types] have an environmental impact. Each one has its own communities of animals and plants that rely on that area to live in. However, overall I fell the largest loss would be stress as they have a very limited trunk area and a large canopy, so for every tiny bit of trunk removed a large canopy [is also removed] so they’re not proportional,” Ballantyne told Science Network.

He added that the lack of planning plus the informal trails coming from tourists and park-goers leads to “networks of damaging trails that need to be structured and maintained for effectiveness”.

“We encourage more landscape-scale research into trail-based fragmentation due to its capacity to impact extensive areas of endangered ecosystems. Management should seek to minimise the creation of informal trails by hardening popular routes, instigating stakeholder collaboration and centralising visitor flow,” the study said.

Image from Friends of Grand Rapids Parks.

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