Climate Risk Assessment Understanding Heat Stress in “Tri-River”
Ariam Ford UA 601 | DECEMBER 9, 2014
Contents Introduction ........................................................................................................................................... 2 Climate Change is Happening ................................................................................................................ 2 Risk in Tri-River..................................................................................................................................... 3 Heat Stress ............................................................................................................................................. 4 The Vulnerable ....................................................................................................................................... 5 Threats to Resiliency .............................................................................................................................. 6 The Vulnerable of Tri-River ................................................................................................................... 7 LB: Adaptive Capacity Observations .................................................................................................... 13 Adaptation Strategies ........................................................................................................................... 13 Next Steps ............................................................................................................................................ 17 Works Cited.......................................................................................................................................... 19
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Introduction The purpose of this report is to position the city of “Tri-River” within the context of global climate change. Focusing on the human health risk of climate change to the city, this paper specifically overviews the impacts of heat stress. Beginning with a presentation of current scholarship regarding heat stress and climate change, this paper hopes to build a consensus that action should indeed be taken to adapt to the future climate risk. Next, a study of heat risk vulnerability in Tri-City is undertaken through a geo-statistical analysis of the cities demography, thus, identifying the areas of the city with the highest vulnerability to heat stress. The paper concludes with a discussion of adaptation strategies and suggestions of next steps.
Climate Change is Happening Research shows that anthropogenic emissions of greenhouse gasses are highest in human history. This trend is driven by economic and population growth. Due to these emissions, the atmosphere and oceans have begun to warm, the amounts of snow and ice have decreased, and sea levels have risen. The Intergovernmental Panel on Climate Change reports that without additional mitigation beyond those in place, global warming is likely to exceed 4˚C (7.2 ˚F) by 2100, however risks associated with extreme weather events will be moderate to high at just a 1-2 ˚C increase (1.8 – 3.6 ˚F) (Pittsburgh Climate Initiative, 2012).
Figure 1: Projected change in average surface air temperature U.S. Climate Resilience Toolkit. (n.d.). Retrieved December 10, 2014, from http://toolkit.climate.gov/image/515
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Risk in Tri-River Serious consideration of changes in the global climate is particularly relevant for Tri-River, especially given that the city is the economic center of the metro-region.
Impacts of climate change for Tri-River and the region include: warmer average temperatures heat waves droughts increases in precipitation more frequent storm events increased flooding (Pennsylvania Department of Enviromental Protection, 2013)
Local threats from climate change facing tri-river include: higher prices and shortages of basic goods Higher susceptibility to flooding Increased public expenditures from responses to extreme weather events Higher rates of infectious diseases higher rate of heat related illnesses (Pittsburgh Climate Initiative, 2012) It is important to note that these threats are not just examples of future scenarios; rather they are beginning to take form in the present and are very likely to intensify in the near future. Research shows that the overall increase in average temperature of the state from the 1990s to the 2000s was 2.4ËšF. A substantial portion of this observed warming is directly attributable to the effects of greenhouse gas emissions. (Pittsburgh Climate Initiative, 2012) Climate sensitive sectors, identified by a major research university, include agriculture, ecosystems and fisheries, forests,
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energy, outdoor recreation and tourism, water, and human health. (The Pennsylvania State University, 2013) This particular study is focused on the human health risk caused by changes in the climate. This is because while many risks can be obscure and intangible to the general public, health risk is something that everyone can identify with and understand as urgent, regardless of their level of knowledge on climate science and adaptation strategies.
There are 5 pathways through which human health is affected by climate change: Mortality from temperature stress (heat and cold) Respiratory and heart disease caused by air quality pollution Mortality and injuries associated with extreme weather events Changes in geographical distribution and prevalence of vector borne diseases Changes in water and air-borne infectious disease
Heat Stress Due to the scope of this academic exercise, rather than focusing on all human health risks in Tri-River, this report only covers the risk caused by heat stress. Heat stress is the leading cause of weather related deaths in the country (Pennsylvania Department of Enviromental Protection, 2013). A study of Chicago found that heat related death is projected to increase from 2.6 deaths per 100,000 to 7.1-19.9 deaths per 100,000 by the end of the century. This information is relevant to Tri-River because it has similar summer temperature trends as Chicago. If similar projections of heat related mortality is applied to the Tri-River metropolitan area, the state could see an additional 300 to 1200 heat related deaths per year (Pittsburgh Climate Initiative, 2012). Short of death, heat stress can also lead to heat exhaustion, heat cramps, heat strokes, and the exacerbation of respiratory, cerebral and cardiovascular diseases. (Pennsylvania Department of Enviromental Protection, 2013) 4|Page
Urban areas such as Tri-River are more at risk because they tend to exacerbate heat-related environmental conditions and the associated health problems. They are particularly vulnerable to heat due to high concentrations of susceptible people, poor urban design and planning, and the interaction between air pollution and heat (Huang, et al., 2001). In urban areas, the Urban Heat Island effect is present, causing significant differences between city centers and surrounding suburbs (Shaw, Colley, & Connell, 2007).
Causes of urban heat island effect: Absorption of short wave radiation from sun in low albedo (reflection) materials and trapping by multiple reflections between buildings and streets surface. Air pollution in the urban atmosphere absorbs and re-emits long wave radiation to the urban environment. Obstruction of the sky by buildings results in a decreased long-wave radiative heat loss from street canyons. The heat is intercepted by the obstructing surfaces, and absorbed or radiated back to the urban tissue. Anthropogenic heat released by combustion processes (traffic, space heating, industry). Increased heat storage by building materials with large thermal admittance. Cities have larger surface area than rural areas and thus more heat can be stored. Evaporation from urban area is decreased because of "waterproofed surfaces" (less permeable materials and less vegetation). Consequently, more energy is put into sensible heat and less into latent heat. Turbulent heat transport from within streets is decreased by a reduction in wind speed. (Kleerekoper, L., 2012)
The Vulnerable "Due to ageing populations, hotter summers induced by climate change, trends towards increasing urbanization and greenhouse-intensive airconditioner usage in developed nations, research on adaptation to extreme heat warrants urgent research and policy attention." (Maller & Strengers, 2011)
The intent of this section is to identify those populations that are most vulnerable to the risks of heat stress. Health risk factors contributing to differentiations in vulnerability include differences in physiological sensitivity to high temperatures and air pollution, socioeconomic variables, and
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spatial locations that are hazardous living spaces (Harlan & Ruddell, 2011). In addition, a range of social and contextual factors increase the susceptibility to heat stress. These include a lack of mobility, sleeping on the top floor of a building, living in a structure with poor building performance variables, and living alone. A range of vulnerable populations suggested by academic research is detailed in the chart below.
Harlan & Ruddell, 2011 •elderly •very young •socially isolated •poor •racial/ethnic minorities •pre-existing illnesses •no access to air conditioning
Hung, et al., 2001 •cardiovasular diseases •respiratory diseases •diabetes •mental disorders •elderly
Maller & Strengers, 2011 •older people •low income households •young children •homeless •mentally ill •urban dwellers
Figure 2: Vulnerable Populations of Heat Stress
Threats to Resiliency This paper identifies two major threats to resiliency relative to heat stress. The first is the reactionary response of the “air conditioning’ solution. The attempt to adapt to heat stress by advocating the installation of air conditioning units is neither environmentally or economically sustainable in the long term. In fact, this method will lead peak demand problems for electrical grids, potentially leading to black outs. Additionally, the increased demand on the grid during periods of heat stress will lead to an increase of the cost of electricity in order to maintain the infrastructure, a
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cost that will be directly passed on to the consumer. This increase in energy costs creates an issue of equity, as it potentially compromises the ability of lower income groups to pay their energy bills. This is particularly concerning, considering that low income is a major factor of heat stress vulnerability (Maller & Strengers, 2011). Secondly, there is an inherent difference resiliency depending on an individual’s socioeconomic context, particularly housing. As a social determinant of health, housing quality plays a major role in the susceptibility of vulnerability to heat stress. Housing can be identified as a threat to resiliency given the historic difficulty it takes to ensure that every citizen in safely and properly housed (Maller & Strengers, 2011).
The Vulnerable of Tri-River The following section presents an initial risk assessment of heat stress in Tri-River by using demographic data to locate the most vulnerable populations within the city. The city of Tri-River is located in the western portion of the state. It sits where the A river and the M river meet to form the O river. Historically, the city’s economic engine was driven by the steel production industry. However, the city’s economy has since shifted towards high tech, robotics, health care, nuclear engineering, tourism, biomed, finance, education and services.
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Population: 305,704 Under 5 4.9% Over 65 13.8% Foreign Born 7.1%
Race White: 66% Black: 26.1% Asian: 4.4% Hispanic or Latino: 2.3%
Median Household Income: $38,029 Housing-Yr Structure Built 1939 or earlier: 50.3% 1940-1959: 24% 1960-1979: 14.4% 1980-1999: 7.6% 2000-2009: 3.6%
Disability Total disabled %14 Disabled 65+ 38.3%
Households W/ Children 21% W/ Relatives 65+ .08% 65+ Living alone 8.6%
Education (Age25+) Less than HS diploma 10.2% HS diploma 30.3% Bachelor's Degree 17.9%
Tri-River @ a Glance
Figure 3: Tri-River at a Glance (2008-2012 ACS 5yr)
Method for mapping the vulnerable The purpose of this risk assessment was to provide an initial identification of the geographical location of the most vulnerable populations to heat stress in Tri-River. This analysis uses populations identified by the literature review as most vulnerable. By graphing these populations by census tract, we are able to see the geographical distributions of vulnerable across Tri-River. Then, using the Getis-Ord General G Statistic (a spatial statistic measuring the degree of clustering for either high values or low values), I was able to identify hot spots, clusters of census tracts based on their statistically significant high percentages of vulnerable populations (z scores above 2.0 at the 95% confidence level). Then, by overlaying the hot spot maps, I was able to determine where the highest levels of clustering of various vulnerable groups coincided. The resulting Maps are shown below.
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Vulnerable Population
Measurable Variable
Elderly
% population over 65
Very Young
% population under 5
Impoverished
% of population living below poverty line
Disabled
% non-institutionalized population with a disability
Poorly Educated
% of population with HS Diploma
Sources: Census 2010 SF1-DP1, ACS12 5yr S1701, ACS12 5yr S1810, ACS12 5yr S1501
% Population over 65
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% Population under 5
% Population disabled
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% Population with HS diploma
*Looking for Cold Spots – statistically significant clusters of low values (lacking HS diploma)
% Population in Poverty
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RESULTS Based on the results, the neighborhood of LB was selected because it is the location where the most vulnerable hotspots (3/5) overlap in one place. Those vulnerable populations include population over 65, disabled, and living under the poverty line. Below are maps of the neighborhood and an accompanying profile
The Neighborhood of LB Natural Environment o Located in NE Tri-River o 1.81 square miles o 303 street Trees o 24 acres of park space Park = 2.1% of land area 4.9 acre/person Population o 4,883 total o Population Density = 4.2 people/acre o Poverty rate: 30.4% LB Black Asian White
Population 60+ Population 75+
79.4% 1.7% 16.1%
City Wide 27.2% 2.9% 67.4%
LB
City Wide
20.6 11.4
19.4 8.3
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ď ś Housing o 2,551 units o 20.3% Vacancy o 63.6% Owner occupied o 36.4% Renter occupied o 55.9% built before 1939 o Median Value: $43,767 (decline 22% between 2000 and 2010) ď ś Land Use o Residential = 32.3% o Mixed Use-Commercial = 6.4% o Mixed Use-Industrial = 1.6% o Institutional/Educational/Medical = 17.4% o Open Space = 42.4% o Roads: 30.38 total Miles (City of Pittsburgh, 2014)
LB: Adaptive Capacity Observations Based on the information collected about the neighborhood under consideration, a variety of positive and negative observations can be made about its adaptive capacity. First, there is quite a bit of open space in the neighborhood, even though the ratio of open space per person is still lower than the overall city average. The neighborhood is also situated on the banks of the M river. This is advantageous because water is a prime strategy to mitigate heat stress. Also, the community is primarily owner occupied. This means that any adaptation measures presented at individual house scale are more likely to take hold, given that owners often have a greater stake in the upkeep and maintenance of their properties. Negatives include a dated housing stock that is conceivably inept to meet future heat stress, high poverty rates, and high number of disabled and elderly populations.
Adaptation Strategies After reviewing the literature, this report divides potential adaptation strategies to heat stress into 5 different sectors: Vegetation, Water, Built Form, Material, and Awareness. Vegetation Vegetation cools the environment by passively shading surfaces that would otherwise absorb radiation. It also cools by active evapotranspiration. Types of urban vegetation include urban forests, 13 | P a g e
street trees, private gardens, and green roofs(Kleerekoper, 2013). Green roofs are a valuable addition to a heat stress adaptation toolbox because of their mitigation of urban heat island affect by reducing the amount of radiation reflected back into the atmosphere. They also have the advantages of aiding in storm water runoff management, increasing a roof materials durability, decreasing energy consumption, noise reduction, and providing space for urban wildlife (Santamouris, 2012).
http://www.epa.gov/heatisland/index.htm Water Water cools a space by the process of evaporation. It also serves as a heat buffer by absorbing heat where there is a large water mass. Flowing water cools by transporting heat out of the area, producing an average cooling effect of 1-3ËšC to an extent of approximately 30 to 35 meters from the water. Water as a heat stress adaptation strategy is most effective where there is a large surface or when water is flowing or dispersed, such as a fountain. (Kleerekoper, 2013)
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Built Form Built Form affects heat stress through building density and geometry. These two aspects influence the incidence of radiation on materials that can store and trap heat. Buildings also obstruct the sky, thereby decreasing the radiative heat loss from street canyons. They also reduce wind speed in an area, which would otherwise transport heat away. Encouraging compact buildings with less external facades (reduce heat storage) and slanted roofs (generate wind) are two ways to use built form in a heat stress adaptation strategy. Building Materials Building materials play a large role in addressing heat stress adaptation. The use of impervious surfaces causes a decrease in evaporation in urban areas. This leads to an accumulation of heat. Increasing the albedo (reflectivity) of materials in the urban scape would result in cooler temperatures. Desirable materials also have high emittance levels, meaning that they store less heat. Ideal building materials for adaptation to heat stress include those with high albedo and high emittance. (Kleerekoper, 2013)
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http://www.epa.gov/heatisland/index.htm
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Awareness Finally, any strategy to increase the resiliency of a community to heat stress must include an awareness component. This first involves a program for educating the community about the risks and vulnerabilities of heat stress. Secondly, it must involve the creation of a Heat Health Warning System. The system uses meteorological forecasts to initiate acute public health interventions. Such warnings include media announcements, the opening of cooling centers, home visits and telephone calls to vulnerable populations, and website bulletins. (O’Neil, 2009)
Next Steps In conclusion, this study suggest the creation of a Heat Stress Task Force to carry on the efforts begun in this paper. The purpose of the task force will be to review the vulnerable populations of Tri-River and to create a Heat Stress Climate Action Plan to address those vulnerabilities. The task force will be charged with creating programing material and acquiring funding and cooperation from stakeholder groups. I suggest that one person from each of the following groups in Tri-River be invited to the task force. Finally, the paper ends with the presentation of a list of suggested action areas and strategies for the task force to consider. Overall, this report serves as an initial case study on the state of heat stress vulnerability in Tri-River. The hope is that leadership will recognize the urgency of this issue and take steps to ensure that all citizens of Tri-River are adequately prepared. Heat Stress Climate Action Task Force Mayor’s Office Arts Commission City-County Task Force on Disabilities Housing Authority Shade Tree Commission Sustainability Commission Urban Redevelopment Authority Youth Commission Office of Emergency Management and Homeland Security Tri-River Emergency Medical Services
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Preliminary task force action areas & strategies
Water
Vegitation
Materials
Awareness
• Fountains • Storm water storage in public spaces • Stream daylighting • Increase evening time activities on the river banks during the summer. Ensure that these events are accessible to all vulnerable populations
• Street trees • Private/Public gardens • Green Roofs/Green Infrastructure
• Cool paving materials • Permeable paving • Building materials with high albedo
• Initiate a Heat Health Warning /Alert systems • Senior Check-In Program • Requiring construction using materials with high albedo and incentivizing for housing with green infrastructure. • Switch to using cool paving materials in public spaces • Construction of community fountains and gardens with lighting, as to be accessible in the evenings. • Subsidize residential green roofs
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Works Cited Aubrecht, C., & Ozceylan, D. (2013). Identification of heat risk patterns in the US national Captial Region. Environmental International, 68-77. City of Pittsburgh. (2014). pittsburghpa.gov. Retrieved from CIty of Pittsburgh: http://pittsburghpa.gov/ Demuzere, M. (2014). Mitigating and adapting to climate change: Multi-functional and multi-scale assessment of green urban infrastructure. Journal of Environmental Management, 107-115. Harlan, S., & Ruddell, D. (2011). Climate Change and Health in Cities: impacts of heat and air pollution and potentioal co-benefits from mitigation and adaptation. Environmental Sustainability, 126-134. doi:10.1016/j.cosust.2011.01.001 Huang, C., Barnett, A. G., Wang, X., Vandckova, P., Fitzgerald, G., & Tong, S. (2001). Projecting Future Heat-Related Mortality Under Climate Change Scenarios: A Systematic Review. Online: U.S. Department of Health and Human Serviced. Kleerekoper, L. (2012). How to make a city climate-proof, addressing the urban heat island effect. Resources, Conservation & Recycling, 30-38. Ligeti, E., Penny, J., & Wieditz, I. (2007). Cities Preparing for Climate Change-A Study of Six Urban Regions. Toronto: Clean Air Partnership. Maller, C., & Strengers, Y. (2011). Housing, hear stress and health in a changing climate: promoting the adaptive capacity of vulnerable households, a suggested way forward. Health Promotion International, 26(4), 492-498. National Center for Atmospheric Research. (2014, October). Climate Change Scenarios. Retrieved from NCAR's GIS Climate Change Program: https://gisclimatechange.ucar.edu/ Natural Resources Defense Council. (n.d.). Climate Change Health Threats in Pennsylvania. Retrieved from National Resources Defense Council: http://www.nrdc.org/health/climate/pa.asp
O’Neill, M. (2009). Preventing heat-related morbidity and mortality: New approaches in a changing climate. Maturitas, (2), 98-103. Pennsylvania Department of Enviromental Protection. (2013). Pennsylvania Climate Adaptation Planning Report: Risks and Practical Recommendations. Pennsylvania Department of Enviromental Protection. Retrieved from http://www.elibrary.dep.state.pa.us/dsweb/Get/Document-92911/27000-REDEP4303%20%20Pennsylvania%20Climate%20Adaptation%20Planning%20Report.pdf Pennsylvania Natural Heritage Program. (n.d.). Climate Change Vulnerability Index. Retrieved from Pennsylvania Natural Heritage Program: http://www.naturalheritage.state.pa.us/ccvi.aspx 19 | P a g e
Pittsburgh Climate Initiative. (2012). Pittsburgh Climate Action Plan. Pittsburgh, PA: Green Building Alliance. Retrieved from http://pittsburghclimate.org/wpcontent/uploads/2011/12/Pittsburgh-Climate-Action-Plan-Version-2-FINAL-Web.pdf Santamouris, M. (2012). Cooling the cities – A review of reflective and green roof mitigation technologies to fight heat island and improve comfort in urban environments. Solar Energy, 682703. Shaw, R., Colley, M., & Connell, R. (2007). Climate Change Adaptation by Design: a guide for sustainable communities. London: TCPA. The Pennsylvania State University. (2013). Pennsylvania Climate Impacts Assessment Update. University Park: The Pennsylvania State University. Retrieved from http://www.elibrary.dep.state.pa.us/dsweb/Get/Document97037/PA%20DEP%20Climate%20Impact%20Assessment%20Update.pdf Union of Concerned Scientists. (2008). Climate Change in Pennsylvania. Cambridge, MA: UCS Publications. Retrieved from http://www.ucsusa.org/sites/default/files/legacy/assets/documents/global_warming/Clima te-Change-in-Pennsylvania_Impacts-and-Solutions.pdf U.S. Climate Resilience Toolkit. (n.d.). Retrieved December 10, 2014, from http://toolkit.climate.gov/image/515
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