Climate change is a long term trend that will affect human dynamics in cities. This is not a section on how to solve climate change, rather an understanding of how it affects people on a cognitive and physiological level.
There are 3 key phenomena to focus on.
Motor vehicle traffic is a major contributor to climate change due to the release of greenhouse gases. In the US cars account for 26% of greenhouse emissions.
Urban expansion also means deforestation which increases impervious surfaces, making city more vulnerable to flooding. Flooding in turn erodes storm water into water streams, increasing the risk of disease contagion.
The third climate change phenomena is urban heat island (UHI) effect, which makes cities several degrees warmer than surrounding areas. The fourth element related to climate change is the rise in extreme weather. This means more frequent floods, hotter summers, colder winters, and hurricane systems.
The demand for new infrastructure in cities as a result of urbanisation is pushing a city’s resilience to breaking points. The replacing of nature with built environments destabilise an ecosystems natural ability to mitigate extreme environmental activities, such as flooding. A recent example of this was the devastation caused by hurricane Harvey in Houston, Texas. One of the major contributors to the high levels of flooding was the ratio of concrete pavement to natural green areas. This caused the city of Houston to become water repellent increasing the expansion and levels of flooding.
There is an argument that flooding in cities is a zoning problem, the allocation of land for development (sidewalks, buildings, roads) rather than for green spaces (parks, natural reserves) is causing cities to flood uncontrollably. Hurricane Harvey damaged over 200,000 homes and nearly 40,000 people were displaced to shelters, other cities, and hotels. This is a significant amount of human disruption. Relating this back to neuroscience, we propose that the displacement of people via these natural disasters has mental health implications. The first is post traumatic stress disorder (PTSD) from the initial shock of experiencing extreme trauma. PTSD has devastating long term effects, such as depression and anxiety. As more extreme weather conditions arise and force people to leave well established lives for new and possibly alien environments, industry should think about how this contributes to isolation and alienation.
The second consideration is the UHI effect occurring in urban areas, which is generated from urban structures, such as buildings or large areas of concrete re-radiating the heat coming from vehicles, power plants, air conditioners, and other heat sources. A lack of natural heat-mitigating elements such as trees providing shade and ventilation can result in people increasingly living in “hot ovens”, with no respite. The UHI effect causes demand for more energy as people struggle to keep buildings cool, which in turn adds more pollutants into the air.
It increases ground level ozone layer, which can be very harmful to children and infants. Most of the current literature concentrates on UHI’s effect on general health and mortality, which are very important factors to consider. However, it is also important to consider what effects UHI has on cognitive performance and in turn productivity due to stress caused by elevated temperatures. Heat stress affects cognitive performance differently, depending on the type of cognitive task and exposure levels. However, one core correlation is that heat contributes to lower cognitive performance as it competes for attentional resources. In other words, as attention is being allocated to respond to the stress of heat it distracts focus from the task at hand. Additional research should be considered to investigate if UHI has an effect on brain development and structure, which could have further effects on productivity.
We need to understand more about the cognitive and psychological effects of displacement. This will help urban designers and engineers understand what type of design interventions and social systems are needed for cities taking in displaced people. Research should especially focus on the effects of social cohesion and social capital. Industry should start to consider how extreme weather might change people’s interaction with the built environment.
Do colder winters or hotter summers cause children and adults to choose shelter over outside activities? What will be the health implications of these new behaviours?
What will staying indoors mean for human-to-human interaction?
Will it change how we socialise? Social cohesion? Could it increase isolation in varied demographics such as the elderly?
What will extreme weather do for economically challenged demographics in terms of quality of life, if they cannot afford to mitigate the effects of weather?
UHI deteriorates the experience of the city as it thermal comfort decreases, this could have an effect on dwell and general engagement with city activities and resources.
A prospective study of depression and posttraumatic stress symptoms after a natural disaster: the 1989 Loma Prieta Earthquake. Nolen-Hoeksema S1, Morrow J. 1991 - https://www.ncbi.nlm.nih.gov/pubmed/1890582
Post-traumatic stress disorder following disasters: a systematic review. Neria Y1, Nandi A, Galea S. 2008 - https://www.ncbi.nlm.nih.gov/pubmed/17803838
A review on the generation, determination and mitigation of urban heat island. Memon RA1, Leung DY, Chunho L. 2008 - https://www.ncbi.nlm.nih.gov/pubmed/18572534
The urban heat island and its impact on heat waves and human health in Shanghai. Tan J1, Zheng Y, Tang X, Guo C, Li L, Song G, Zhen X, Yuan D, Kalkstein AJ, Li F. 2010 - https://www.ncbi.nlm.nih.gov/pubmed/19727842
Effects of heat stress on cognitive performance: the current state of knowledge. Hancock PA1, Vasmatzidis I. 2003 - https://www.ncbi.nlm.nih.gov/pubmed/12745975