Exploring Alternative Methods of Environmental Analysis

While the majority of businesses focus on economic repercussions of business decisions, almost all Civil Engineering infrastructure projects have an impact on the environment as well. The most traditional method of analyzing environmental impacts of projects is through a Life Cycle Analysis, which tracks emissions such as Carbon Dioxide (CO2) or Greenhouse Gasses through the production, construction, use, and end of life of projects. However, there are several other tools that can be used, including Ecological Footprint and Planet Boundary. These two tools are introduced with discussion on how to incorporate them into pavement design. The concept of Ecological Footprint, or EF, originated in the early 1990s. The concept is based on nature’s capital, and the fact that certain needs are necessary for human life. These needs include healthy food, energy for mobility and heat, fresh air, clean water, fiber for paper, and clothing and shelter. The goal of the EF was to develop a scientifically sound calculation and that could relate to clear policy objectives. In addition, it needed a clear interpretation, to be understandable to non-scientists, and to cover the functioning of a system as a whole. Finally, the metrics had to be based on parameters that are stable over long periods of time so that minor or local fluctuations would not compromise quantifications. The concept of Planet Boundary was first proposed in 2009 and is defined as a “safe operating space” for humanity. According to this theory, if human activities stay within the safe space, the earth is able to absorb the human activities with no long-term harm to the environment; however, if the human activities move outside of the safe space, the Planet Boundary theory states that long-term harm may occur to the environment. These spaces are associated with the earth’s biophysical subsystems and processes. support systems, genetic diversity, species, and ecosystems. Seven years later the UN released the Brundtland Commission Report, which is probably the most recognizable milestone in the UN’s sustainability development (Brundtland, 1987). The primary theme of the Brundtland Commission reads that sustainability “meets the needs of the present without compromising the ability of future generations to meet their own needs.” This theme is independent of protecting the environment, but the concept of the environment is still woven into the fabric of the theme. In 2002 the UN hosted a World Summit on Sustainable Development, which for the first time defined what are called the three pillars of sustainability: economics, environment, and social (UN, 2002). While the UN has continued to explore the concept of sustainably, the 2002 summit provided the foundation of the three pillars, which are generally accepted as the standard definition of sustainably. It is through this definition that organizations much closer to the pavement community, such as the American Society of Civil Engineers (ASCE), have also embraced the concept of sustainability. 1.2 What is sustainably – the American Society of Civil Engineers (ASCE) ASCE was founded in 1852, is the oldest engineering society in the United States, and has more than 150,000 members across 177 countries. ASCE defines sustainability as: “A set of environmental, economic and social conditions in which all of society has the capacity and opportunity to maintain and improve its quality of life indefinitely without degrading the quantity, quality or availability of natural, economic, and social resources.” This definition clearly incorporates the three pillars of sustainability (economics, environment, social) as developed by the UN. Not only does ASCE have a formal definition of sustainably, but the ASCE Code of Ethics (ASCE, 2006) mentions sustainably on multiple occasions. The ASCE Code of Ethics has four fundamental principles and seven fundamental canons. Sustainability is mentioned at the very beginning of the Code in the first principle: “using [engineer’s] knowledge and skill for the enhancement of human welfare and the environment.” This principle directly addresses two of the three pillars of sustainability, environment and social. In addition to the first principle, sustainability is mentioned in several of the seven canons. Canon 1 says “engineers shall... strive to comply with the principles of sustainable development.” Canon 1 also states that engineers need to work for the advancement of safety, health, and wellbeing of their communities (social pillar) and the protection of the environment (environment pillar). Canon 3 continues the sustainability theme by asking engineers to endeavor to extend public knowledge of engineering and suitable development (social pillar). By incorporating sustainably concepts into both the principles and canons, ASCE enforces the commitment of the civil engineering community in understanding and incorporating sustainable practices. 1.3 Quantifying and qualifying sustainability Using the concept of the three pillars of sustainability, economic, environment, and social, many quantifications and qualifications have been developed. The economic pillar is by far the most developed, with concepts such as Life Cycle Cost Analysis, present/future/annual worth, rate of return, and benefit/cost ratio. On the other end of the spectrum, the social pillar is the least developed. While tools are available, such as the Oxfam Doughnut, Human Development Index, and Social Impact Assessment, there are limited metrics that either quantify or qualify the social aspect of civil engineering projects (Braham and Moon, 2016). The development of the environment pillar lies somewhere in between the economic and social pillars. There has been significant work performed on Life Cycle Analysis (LCA). For example, LCA has been utilized to compare flexible pavement to rigid pavement (Weiland & Muench, 2010), pavement life (Harvey et al., 2016), and has provided the foundation for a Pavement Life Cycle Assessment Workshop held at the University of California Davis in May, 2010. Other tools have been developed in roadways as well, such as the Greenroads rating system. Greenroads, founded as a company in summer 2010 by Jeralee Anderson and Steve Muench, has eleven categories of project requirements and thirty-seven voluntary requirements. Project requirements that revolve around environment concepts range from runoff flow control to ecological connectivity to environmental training (Anderson & Muench, 2013). Finally, tools have been utilized in order to better capture environmental influences of pavements through Environmental Impact Assessments (EIA) (Moretti et al., 2013). EIAs allow for a systemic analysis of the impact of pavement design, production, construction, use, and end of life on the environment. While tools such as LCA, Greenroads, and EIA have been utilized for pavements, there are two tools that have been developed that have not been utilized for pavements. These tools are Ecological Footprint and Planet Boundary. This report will provide an overview of these tools, along with recommendations for how to potentially leverage these tools to better understand the environmental impact of pavements. 2 ECOLOGICAL FOOTPRINT Ecological Footprint, or EF, was developed at the University of British Colombia in the early 1990s (Wackernagel, 1994). The concept is based on nature’s capital, and the fact that certain needs are necessary for human life. These needs include healthy food, energy for mobility and heat, fresh air, clean water, fiber for paper, and clothing and shelter. The goal of the EF was twofold: develop a scientifically sound calculation and clearly relate to policy objectives. In addition, it needed to have clear interpretation, be understandable to non-scientists, and cover the functioning of a whole system. Finally, the metrics had to be based on parameters that are stable over long periods of time so that local or other minor fluctuations would not compromise quantifications. EF is based on taking specific economy or activity’s energy needs, and converting that energy and matter to land and water needs. In short, this is determined through a five step calculation. First, the consumption of either a city, region, state, or country is calculated and split into food, housing, transportation, consumer goods, and services. Second, land area of the analysis zone is appropriated into either cropland, grazing, forest, fishing ground, carbon footprint, or built-up land. Cropland is land available to produce food and fiber for human consumption, feed for livestock, oil crops, and rubber. Grazing is land that can raise livestock for meat, dairy, hide, and wool products. Forest provides the land for lumber, pulp, timber products, and wood for fuel, while fishing ground covers the primary production area required to support the fish and seafood caught. While forest is one category for providing wood products, the carbon footprint is the amount of forest land required to absorb CO2 emissions. Finally, the last category is builtup land, which is the area of land covered by human infrastructure. Once the consumption and land use is identified, both resource and waste flow streams are calculated, which is the third step in the calculation. The fourth step is the construction of a consumption/land-use matrix. This matrix shows all categories of both consumption and land use and indicates where there is not enough land for certain consumptions as well as which land is excess land. The deficiencies give numbers greater than one while the excess give numbers less than one. The fifth and final step sums all of the numbers and provides an estimate of EF for a region. These five steps are summarized in Table 1. Table 1. Five-step calculation for Ecological Footprint Step Description of each step One Consumption of food, housing, transportation, consumer goods, and services determined Two Land area appropriated into cropland, grazing, forest, fishing ground, carbon footprint, or built-up land Three Resource and waste flow streams calculated Four Construction of a consumption/land-use matrix Five Sum all of the numbers, provide an estimate of EF for a region When considering EF from a country level, it is interesting to note that the highest EF countries are from the Middle East according to a 2010 report published by the Global Footprint Network (Ewing et al., 2010). This report states that the United Arab Emirates (UAE) and Qatar were producing EFs greater than 10.0 global hectares per person. This number states that if every person in the world was living the standard of living of the average UAE citizen living on UAE’s resources, we would need over ten earths to sustain life. The next grouping down consists of western, fully developed countries, which required approximately 5-8 earths to maintain their standard of living. The list continues down through second world, developing, and third world countries. According to the report, it is interesting to note that the countries requiring less than one earth is quite diverse both geographically and socio-economically, from the Democratic Republic of the Congo (population 63 million) to Bangladesh (population 158 million) to Puerto Rico (population 4 million). One study that has been performed is using impervious surfaces, which includes pavements, as a proxy measure for EF (Sutton et al., 2009). Since it is relatively easy to calculate constructed areas per person from satellite images, it is convenient to use this measurement to determine EF instead of more difficult measures such as fiber and fuel wood consumption, two traditional inputs into an EF analysis. By using aerial photographs from thirteen cities in the United States, impervious surfaces (such as rooftops, sidewalks, parking lots, and roadways) were identified and the ratio of impervious surfaces to pervious surfaces (such as lawns, parks, and golf courses) over 100 random points across the image were classified. An R2 value of 0.78 was found between the impervious surfaces and the EF, providing decent correlation between percentage of impervious surfaces and EF. Sutton et al. (2012) continued work in this area by developing a monetary correlation between impervious surfaces and consumption of ecosystem services. There are, of course, some drawbacks to the EF concepts. First, the physical consumptionland conversion factor weights do not necessarily correspond to social weights. The analysis focuses one hundred percent on the metrics at hand, but do not consider the social choices people have to make. Second, the EF does not distinguish between sustainable and unsustainable use of land, only that land is being consumed. Therefore, forest could be clear-cut or sustainably harvested, two processes to extract wood from nature, but the EF would treat these practices as the same. A third criticism is that in the EF model there are many options to compensate for CO2 emission and CO2 assimilation, such as by forest, chemosynthesis, and autotrophs. However, the EF model only compensates for CO2 emission and assimilation by forest, neglecting the other options. A fourth criticism is that there is a significant correlation between population density and resource endowment. As populations move away from rural living to urban living, the EF will increase significantly, especially as the analysis zone shrinks. This artificially inflates the EF of urban areas while perhaps underestimates the true EF of rural areas. The fifth and final criticism discussed here is that EF is hard to use as a planning device. While it is noble to attempt to decrease the EF, there are few tangible concepts that agencies can focus on to begin the reduction, making it difficult to leverage. While no measure is truly perfect, these deficiencies have led to the development of other metrics, including the Planet Boundary.