C02 EMISSIONS + URBANISM: OFFSETTING OPPORTUNITIES WITH URBAN FARMING
C02 emissions are a fundamental contributor to greenhouse gases in our environment, majority of these emissions are directly created from urban behaviors. These behaviors are prompted by how we choose to plan our infrastructure (transportation, energy,waste) and the spatial configurations/use types of our urban forms. This project began as an investigation of how C02 emissions are correlated to urbanism/density growth by examining two rather contrasting cities, and identifying pre existing density patterns in the forms of population, urban growth, land use, and C02 distribution. The initial goal was to explain how C02 emissions, as caused by urban behaviors, are threatening human life.
By using data driven methods of graphical visualization a new understanding of growth relationships emerged. And then resulted in a reinterpretation of how the city of Detroit could be replanned so that C02 emissions could be offset from industrial processing, while at the same continuing to support urban growth.
The two cities used for this research project were Detroit,MI and Greenfield,CA. Detroit was selected because it is a city with a densely developed metropolitan area, that is also heavily reliant on vehicular transportation. Greenfield is quite the opposite where it is a very dense agricultural city, and majority of the land is allocated to agricultural production.
By reviewing satellite images it is easy to identify how contrastingly different the land use of these two cities are.
In order to begin to compare the two cities it is necessary to compare population densities. Surely a larger city will produce more C02 per year. That alone is a function of scale. However, by looking at the cities in population mile blocks a comparative analysis could be achieved. Using Arc GIS to overly population blocks , comparative density measurements were made as related to geographic location. The population data was obtained from ArcGIS online, and was authored by ERSI in 2010 . The orange block in Greenfield corresponds to the city fabric of the developed portion of the city. The HTML popup tool was used in ArcGIS to reveal more precise numbers of individual blocks. To much surprise the developed orange areas in Greenfield and Detroit came out to average nearly 6,000 people per square acre of development. In theory this indicates similar C02 emission quantities should be present in the orange urbanized areas of both cities.
C02 vs URBAN DEVELOPMENT
Using ArcGIS a C02 emission array was overlaid with urbanized areas. US census bureau data was used to define urbanized areas (expressed as a cross hacth); the data set was retrieved from ARCGIS online. And the C02 emissions data set came from ArcGIS online and was prepared by Purdue students. Overlaying the urban and C02 data indicates how C02 emissions may follow urban growth patterns. While also indicating how densities of C02 is related to various urbanized areas of a city. And thereby also indicating the threat CO2 could have to human urban dwellers. In the maps the darker gradation indicate a higher density of C02 .
In Detroit the C02 emissions seem to loosely follow urbanized areas. However, the density of CO2 seems geographically unrelated to population density. Meaning there is indeed a correlation between urban growth and CO2. But it does not seem to be associated with population densities. Yet it is rather clear that higher densities of C02 are rather present in urban spaces. And In Greenfield the CO2 emissions seem to almost move away from the urbanized portions of the city. And similar to Detroit they do not appear to be associated with population density.
After understanding how C02 emissions are impacting, and related to, urbanized areas of the two cites it became necessary to understand precisely how C02 emissions are being created.
C02 emission data and percentages was obtained from the EPA emission inventory warehouse. According to the EPA the percentages of C02 in Detroit are broken down as depicted here. As can be noted from the chart refineries are by far the largest contributor of C02 emissions in Detroit. The question then becomes where are these emissions taking place in the city? And furthermore how are consumption of resources driving emissions upward?
Further obtaining C02 emission data for the primary manufacturing and industrial facilities in Detroit from the EPA emissions warehouse; a map was made using Data Appeal and formatted Excel data. This map geospatially located the polluting facilitates, and proportionally expressed the annual tons of C02 emissions created from each facility. The west side of Detroit by far suffers the worst from C02 emissions due to the oil refinery (largest triangle)
In Greenfield C02 emissions are relatively difficult to quantify with precision. This is because the agricultural farming fields function as natural C02 sinks . Sinks store C02 , preventing it from harming the environment and human health, while also aiding in agricultural production. Additionally the quantity of C02 emissions is significantly reduced as indicated from the C02 vs Urban development analysis.
Therefore it is more beneficial to determine how many tons of C02 the farming fields in Greenfield can hold. Creating a map with the online California Important Farmland Finder an analysis was done to determine how much farmland was in existence within the city Greenfield. Then using a factor of 50 tons of C02 per every hectare, the capacity of C02 that the farming fields could contain on an annual basis was determined.
The next logical step was then to relate CO2 emissions to human health.
Looking at facilities that directly relate to urban behavior-oil, waste, energy, and water treatment, it was determined how many units each facility would need to produce per day in order to start polluting the air enough to start killing people with C02. The annual emissions of each facility was converted to a daily unit, then a bench mark of 1,600 PPM (death within 4hrs of exposure) of C02 was used to find the tipping point to human death. After organizing the data and formulas in Excel geospatial comparisons were made to understand how this sort of growth may affect additional coverage of urban spaces. While also identifying just how threatening C02 emissions are .
The results are rather outlandish quantities. However, it is successfully illustrated how when these sort of facilities produce more to accommodate urban growth, the air quality of surrounding areas can be effected substantially.
Since C02 emissions are not on the rise in Greenfield, due to the sink effect of the agriculture, it was determined how many daily units could be manufactured without exceeding the C02 limits that would be offset with vegetated land. Using the same percentage break downs as Detroit, tipping point limits were then determined if similar urbanistic manufacturing demands were present in Greenfield as in Detroit.
Utilizing the knowledge that was gained from the previous research, a twenty year modified growth scenario was animated for the city of Detroit. The scenario assumes a 2% annual growth of CO2 emissions. Then associates an agricultural envelope that would need to be created to proportionally offset the growth in emissions.
This study introduces a feasible hybrid form of land use, in reaction to urban demands, where industrial and agricultural urban forms are developed conjointly. In the particular case of Detoit a new source of economic revenue could also be introduced by providing farming lands adjacent to these industrial facilities. And furthermore indicates the benefits of high density development (more room for farm lands), while providing a beneficial utilization of abandoned portions of the city
Particular thanks to Professor Constance Budurow , of Lawrence Technological University, for facilitating the graduate seminar that incubated this research.
This project is also featured in a Data Appeal blog post . http://www.dataappeal.com/co2-emissions-and-urbanism/
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