Environmental Pollution 202 (2015) 146e152
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Urban metabolism: Measuring the city's contribution to sustainable development L. Ferreira Leonardo S. Conke*, Taina Sustainable Development Center, University of Brasília, Brazil
a r t i c l e i n f o
a b s t r a c t
Article history: Received 6 November 2014 Received in revised form 19 March 2015 Accepted 21 March 2015 Available online
Urban metabolism refers to the assessment of the amount of resources produced and consumed by urban ecosystems. It has become an important tool to understand how the development of one city causes impacts to the local and regional environment and to support a more sustainable urban design and planning. Therefore, the purpose of this paper was to measure the changes in material and energy use occurred in the city of Curitiba (Brazil) between the years of 2000 and 2010. Results reveal better living conditions and socioeconomic improvements derived from higher resource throughput but without complete disregard to environmental issues. Food intake, water consumption and air emissions remained at similar levels; energy use, construction materials and recycled waste were increased. The paper helps illustrate why it seems more adequate to assess the contribution a city makes to sustainable development than to evaluate if one single city is sustainable or not. © 2015 Elsevier Ltd. All rights reserved.
Keywords: Urban metabolism Urban sustainability Industrial ecology
1. Introduction Among the many challenges concerning sustainable development, one that deserves special attention is urban sustainability. The difficulty in balancing quality of life and preservation of natural resources is evident in urban areas, where expectations about the availability of employment, housing and culture exist together with hopes for pure air, mental and physical health and contact with nature. In these dominated and occupied landscapes, humans reorganize and redistribute resources in order to create opportunities, changing the functioning of ecosystems and causing environmental problems (Alberti et al., 2003). The study of urban sustainability can be carried out through different perspectives. One that has been recognized as adequate and consistent compares the city to an ecosystem or an organism, having inputs, transformation and outputs of material and energy, i.e., a metabolism. It assumes that the maintenance of life involves the conversion of natural resources in goods, services and waste. The first time that this idea was related to an urban system was in the early 1920s, with Burgess (1925). However, the landmark paper of Urban Metabolism was developed by Abel Wolman in 1965,
* Corresponding author. Postal address: Universidade de Brasília, Campus Unirio Darcy Ribeiro, Faculdade de Administraça ~o, Contabilidade e Economia, versita Brasília, 70910-900 DF, Brazil. E-mail address: [email protected] (L.S. Conke). http://dx.doi.org/10.1016/j.envpol.2015.03.027 0269-7491/© 2015 Elsevier Ltd. All rights reserved.
when he studied the impacts of material consumption and waste generation of a hypothetical American city of one million people. Urban metabolism can be understood as “the sum total of the technical and socioeconomic processes that occur in cities, resulting in growth, production of energy, and elimination of waste” (Kennedy et al., 2007). If we assume that sustainable development is the “development without increases in the throughput of materials and energy beyond the biosphere's capacity for regeneration and waste assimilation” (Goodland and Daly, 1996), then the urban metabolism approach represents a comprehensive framework that helps monitor the transformation occurring in cities, as well as their contributions to sustainable development (Hoornweg et al., 2012). Studying the flows of materials and energy throughout a city became (more) useful when human activities started affecting the ber, 2004). If city natural cycles of other living organisms (ab'Sa growth is achieved by increased resource throughput, then environmental issues and economic costs depend on the management of the inputs and outputs of material and energy that takes place in urban spaces (Newman, 1999). Unsustainable metabolic processes can cause the exhaustion of resources, impacting the environment in local and regional scale and turning the relationship between urban growth and natural space into a real problem. According to Kennedy et al. (2011), an urban metabolism analysis serves four main purposes: the first one is related to the assessment of materials and energy flows throughout a city. It is a
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basic accounting effort that can provide scientifically valid and representative data for urban planning. The resultant evaluation shows the efficiency in resource use, its future need, the existence of any environmental burden, the contribution of recycling and the capacity of waste treatment, enabling a better awareness of how much impact human activity (social, economic and political) is causing in the natural environment (Brunner, 2007; Holmes and Pincetl, 2012). The second application aims to quantify greenhouse gas (GHG) emissions, a metric which is part of urban metabolism itself, but it turned into an independent contribution due to its relationship to climate change. Third and fourth applications use material and energy evaluation to support decisions concerning public policy. In order to deal with problems such as pollution, sewage treatment, resource scarcity, water shortage and the formation of heat islands, different options in urban design are assessed with the aid of mathematical models, which shows the choices that best balance greater social and economic advancements with lower ecological effects (Kennedy and Hoornweg, 2012; Hoornweg et al., 2012). Therefore, considering the growing relevance of urban metabolism studies, the purpose of this paper is to measure the changes in material and energy use occurred in Curitiba (Brazil) in the decade of 2000e2010. The gathering of data regarding this city's flows of materials and energy in ten years represents the first step to a more sophisticated analysis, and will hopefully support planning and decision-making regarding its sustainability. Besides the accounting contribution, the paper expands the comprehension of the relationship between urban regions, highlighting how industrialized cities are now more dependent on the land space available (only) beyond its geographical limits.
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methodological obstacle. They represent a more integrative approach where social and economic aspects can be examined in the context of urban metabolism (Kennedy et al., 2014). Although urban metabolism studies have evolved over the years, some difficulties persist. The main ones, as anticipated by Wolman (1965), involve data availability and the gathering of information. One reason is that it is actually impossible to completely evaluate any urban metabolism (Brunner, 2007), as cities are present in global markets and their sustainability depend on resources available elsewhere; thus, a metabolic analysis would only be complete if it was able to identify this complex inter-municipal relationship, with the entire description of the origins and destinations of resources, produced goods and waste. In some cases, data available for the local level is less reliable than for the national level, as international transactions are better controlled (Kennedy et al., 2007; Hoornweg et al., 2012). Another challenge is to increase proficiency in data collection and management. Hoornweg et al. (2012) advises that “data is very fragmented and not regularly collected and the studies very much adopted a ‘best available data’ approach”. Even though Curitiba has a fairly decent official database, quality in reporting and even a department that control statistics, data was still dispersed and its gathering demanded more effort than it should be necessary. Nonetheless, we were able to contribute with a satisfactory overview of how the city has changed its resource consumption and waste production. Also, the ten-year approach represents a step further in usual urban metabolism studies, that due to (not) available data and (not) continuous monitoring, generally show only one moment (one year), reducing the possibility of comparison. 3. Case study
2. Methods Developed over the years, urban metabolism methodology is nowadays sufficiently robust, consistent and well anchored in existing academic literature. Integrated frameworks allow the examination of energy and material flows in complex systems, shaped by various social, economic and environmental forces (Holmes and Pincetl, 2012). The specific framework adopted to assess the urban metabolism of Curitiba was proposed by Kennedy and Hoornweg (2012). They presented the basic data that should be collected in any attempt to evaluate the urban metabolism of one city or region. Requirements for Abbreviated Urban Metabolism Studies refer to inflows (water, construction materials, fossil fuels, electricity etc.) production (food, wood etc.), stocks (minerals, nutrients etc.) and outflows (air emissions, wastewater and solid waste). One of the contributions of this model is the possibility of comparison between different locations around the world, as the essential indicators are suggested along with standardized measuring units. Considering that the main purposes are to provide a quantitative measure of Curitiba's material and energy flow and to understand the city social and economic transformation in ten years, we also included in the analysis some of the variables from the works of Newman (1999) and Kennedy et al. (2014). Newman (1999) is known for extending the metabolism model, in one of the first efforts to add social issues to urban studies, showing how resources are being used to create opportunities. He introduced variables about settlement dynamics and livability, which should be fully integrated in urban metabolism studies (Kennedy et al., 2011). Kennedy et al. (2014) used the Abbreviated Urban Metabolism framework to measure and compare almost 15 megacities. They added parameters to describe how the basic infrastructure and the services offered for households can improve living conditions in the city, reinforcing the need to measure social matters. These adjustments were considered appropriate and did not represent any
Curitiba is located in the south portion of Brazil, and it is the (see Fig. 1). Officially administrative capital of the state of Parana founded in March 29th, 1693, it was first dedicated to mining, agriculture and livestock in the 17th century. Later, with the arrival of several groups of immigrants and the building of railroads connecting it to the sea, Curitiba became one of the biggest industrial production areas of the state. Nowadays, population is about 1.8 million people (the 8th most populated city in Brazil) and population density is 4027 inhabitants/km2. Regarding its economy, Curitiba raised its Gross Domestic Product (GDP) from US$ 8 billion ~o Paulo, Rio de (2000) to about US$ 32 billion (2010), following Sa Janeiro and Brasília as the 4th biggest GDP of Brazil. In the social level, the Human Development Index (HDI) went from 0.750 to 0.823 in the same period, ranking 10th in Brazil (PMC, 2014; IBGE). Curitiba has a land area of about 435 km2 and is located 945m above sea level. With a typical subtropical climate, the average temperature is 21 C in the summer and 13 C in the winter, rather cold for Brazil. The annual solar radiation in Curitiba (1481 kWh/ ~o Paulo (1622 kWh/m2) and Rio de Janeiro m2) is below cities like Sa (1694 kWh/m2) and the average annual precipitation is about 1400 mm (Hoornweg et al., 2012; PMC, 2014; INMET, 2014). Similarly to the whole state, the main biome in Curitiba is the Atlantic Forest, and the city itself is served with 29 parks and 115 million m2 of green areas, which makes an average of 64.5 square meters per capita (m2/cap), above the recommended standard of 40 m2/cap (Medeiros, 1975; Singh et al., 2010). At the same time, the building gross floor area is about 92 million m2, being 69% of residential areas and 31% of non-residential areas. We chose to study the urban metabolism of Curitiba for some reasons. First, the city is widely recognized for its efforts concerning sustainability. In the 1970s, instead of using vacant land to real estate speculation, the option was to create new parks and green areas, an alternative better suited for ecological preservation and
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Fig. 1. Location of Curitiba (city) and Parana (state) in Brazil. Source: IPPUC, IPARDES, IBGE.
population well-being (PMC, 2014). From 1989 to 2004, three consecutive administrations made important changes in urban architecture, public transportation and waste management, planning the city with special attention to the environment. Nevertheless, after this period, Curitiba experienced the same economic and social transition that happened throughout the whole country: an increase of employment and revenue along with an aggravation of violence, traffic and pollution. Hence, the idea was to identify through material and energy flows, if a city known for its dedication to green issues is able to profit from the benefits associate to economic and social growth without worsening problems such as pollution, loss of biodiversity and natural degradation. The second reason is that there appears to be a lack of urban metabolism studies in Latin American cities. In a chronological review, Kennedy et al. (2011) found a total of 36 studies, where none was from a South or Latin American city. One of the first initiatives was found in Hoornweg et al. (2012), with a preliminary assessment of Sao Paulo and Rio de Janeiro in Brazil, and Buenos Aires in Argentina, among other cities in Asia and Africa. Sao Paulo and Rio de Janeiro were again considered among other megacities around the world to be part of the urban metabolism project carried out by Kennedy et al. (2014). Thus, we find it appropriate to expand urban metabolism studies to other big cities, especially in developing countries like Brazil. Understanding the metabolic processes in these countries is relevant because they are (now) also accounted for the responsibilities of natural preservation and GHG mitigation and the need to develop without neglecting environmental issues became more noticeable in such regions. 4. Results Tables 1e3 summarize the Urban Metabolism of Curitiba in 2000 and 2010. Tables 1 and 2 present, respectively, gross and per capita volume of materials and energy consumed and produced in the city, as well as its variation in ten years. In Table 3, selected indicators reveal the livability and the quality of services provided in Curitiba.
Regarding material inputs, Curitiba has shown a slight increase in the total food intake (13%); yet, per capita food intake had almost is the no gain (2%). It is relevant to point out that the state of Parana first in grain production in Brazil, especially soybean and corn. Nonetheless, a completely urban area and without rural households, Curitiba's food, wood and mineral production is minimal, and it has decreased over the years, making the dependency on other external resources more noticeable. Well served by rivers, Curitiba was able to maintain its level of water consumption of about 160 daily liters per capita. Investments made in infrastructure helped spread access to drinkable water to a number of households located outside the center area e only 0.10% of households were without access in 2010. Consumption is below other large cities as S~ ao Paulo (197 l/cap/day) or Rio de Janeiro (292 l/cap/day), which have greater industrial activity and higher temperatures (Hoornweg et al., 2012). However, per capita water consumption in all these cities is inferior to other places in developed countries as Vancouver, Canada (554 l/cap/day) (Moore et al., 2013) and London, England (324 l/cap/day) (IWM, 2002), or even in developing countries as Shenzhen, China (734 l/cap/day) (Zhang and Zhifeng, 2007). Data found also reveals some trends in electricity and energy use. The commercial sector had the greatest increase in electricity use (46%). Apparently, industry adopted other types of energy sources, as natural gas (þ243%) and coal (þ5878%). Even though fossil fuels still represent the most used type of energy, it had the least gain (12%), which will (eventually) help slowing down GHG emissions. Along with energy, the city consumed more construction materials (þ57%). For instance, per capita construction material use was similar to London (3757 kg/cap/yr) (IWM, 2002). This is probably due to the vertiginous growth of the real estate market, which had its peak in 2010, with more than 33,500 construction permits approved. Farm land, formerly used for (family) agriculture had been employed for building, in order to accommodate real estate demands in the city. The results of the economic expansion can be observed in the
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Table 1 Urban metabolism of Curitiba e gross value. Material Category Inputs Food intakea Electricity consumption (total) Residential Industrial Commercial Public Services Other Energy consumption (total) Natural gas Fossil fuelsb Coal (mineral þ vegetable) Biomass/biofuels Construction materials (use) Cement Steel Aggregates (sand, gravel) Water consumption Production Food Wood Construction materials Cement Steel Minerals (clay, gold, crushed stones) Water production (surface water) Stocks Minerals (clay, gold, crushed stones) Landfill waste (accumulated) Outputs Municipal solid waste Domestic and public waste Recyclable waste Healthcare waste Toxic waste Tree and junk waste Wastewater GHG emissionsd Air emissions Total suspended particulate (TSP) Smoke Inhalable particles Sulfur dioxide (SO2) Nitrogen dioxide (NO2)
Unit
2000
2010
%
Source
ton GW/h GW/h GW/h GW/h GW/h GW/h TJ TJ TJ TJ TJ ton ton ton ton ML
503,535 3423 1251 931 897 332 12 58,010 1969 47,184 6 8851 4,221,841 371,432 146,985 3,703,424 90,906
567,457 4239 1498 1057 1314 358 12 76,255 6748 52,949 330 16,228 7,308,036 628,935 239,836 6,439,265 103,529
13 24 20 14 46 8 7 32 243 12 5878 83 73 69 63 74 14
IBGE
ton m3 ton ton ton ton ML
2394 4,110c 940,993 680,506 260,487 30,368 162,771
1303 2738 1,256,202 953,570 302,632 15,173 169,086
46 33 33 40 16 50 4
SNIC, CBIC WSA DNPM SANEPAR, SNIS
ton ton
1,427,256 3,607,122
560,409 8,711,683
61 142
DNPM PMC, IPPUC
ton ton ton ton ton ton ML t-CO2eq mg/m3 mg/m3 mg/m3 mg/m3 mg/m3 mg/m3
702,974 532,135 132,173 3807 7286 27,573 58,594 3,174,630 158 86 22 15 11 24
728,453 462,587 193,470 2704 8495 61,197 90,486 3,515,890 107 36 16 27 3 25
4 13 46 29 17 122 54 11 32 58 29 79 71 3
COPEL, COPEL, COPEL, COPEL, COPEL,
IPPUC IPPUC IPPUC IPPUC IPPUC
COPEL ANP COPEL COPEL SNIC, CBIC IABr ANEPAC, DNPM SANEPAR IBGE, PMC IBGE
PMC, IPPUC PMC, IPPUC PMC, IPPUC PMC, IPPUC PMC, IPPUC SANEPAR, SNIS ECOWOOD IAP IAP IAP IAP IAP
Notes. a Available reliable data for the years 2002 and 2009. b Diesel oil, fuel oil, gasoline, aviation fuel, liquefied Petroleum gas and kerosene oil. c Data from 2004. d The only local GHG inventory made in Curitiba dates from 2008, number used in the column of 2010; for the 2000 calculation, the source was Olivier et al. (2012).
material outflow data, especially on the larger generation of wastewater (54%). The city extended the infrastructure, leaving only 0.62% of the households without sewage treatment. The amount of solid waste per capita produced decreased 6% along with a raise of 33% in the recyclable waste. Comparing to a city with similar population as Budapest (1.7 million people), domestic waste discharged in 2010 was almost half, being 335 kg/yr against 630 kg/ zi and Szabo , 2009). These specific yr of the Hungarian city (Poma results are due to Curitiba's long-time focus on selective collection, being one of the best examples in Brazil. Since 1989, local administration has reinforced the need for recycling and supported continuous programs to maintain domestic and industrial waste separation; the urban metabolism data reveal the efficacy of such investments. Air emissions have dropped 32% in ten years, despite industrial expansion. Excluding the bigger amount of inhalable particles, most components showed descent in the period analyzed. According to local administration, the particles are within acceptable standards, even though it is necessary to improve measurement
techniques and equipment. GHG emissions still close to Brazilian average (2.2 ton cap/year), but way below cities in other developing countries as Russia (12.2 ton cap/year), South Africa (9.2 ton cap/ year) and China (6.2 ton cap/year) (UNDP, 2010). Among the reasons, there is the preservation of the several open spaces, parks and green areas existent in Curitiba, which provide ecosystem services such as air filtration, rainwater drainage and micro climate regulation (Bolund and Hunhammar, 1999). Furthermore, most of Curitiba's electrical supply comes from the hydroelectric power plant of Itaipu, a rather clean energy source. Finally, the excessive number of automobiles and the quality of the public transportation system has reinforced the use of buses and bicycles within the city. Data on livability and on quality of services helps understand the changes between 2000 and 2010 (Table 3), and this variation is reflected in the amount of materials and energy used. Almost all indicators of Curitiba's livability moved upward, showing social improvement; nevertheless, they remain below recommended levels. Employment and income were congruent to national patterns,
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Table 2 Urban metabolism of Curitiba e Per capita value. Material category
Unit
2000
2010
%
Source
Population Inputs Food intake Electricity consumption Residential Industrial Commercial Public services Other Energy consumption Natural gas Fossil fuels Coal (mineral þ vegetable) Biomass/biofuels Construction materials (use) Cement Steel Aggregates (sand, gravel) Water consumption Outputs Solid waste Domestic and public waste Recyclable waste Healthcare waste Toxic waste Tree and junk waste Sewage GHG emissions
Inhabitants
1,587,315
1,751,907
10
IBGE
kg/cap/yr kWh/cap/yr kWh/cap/yr kWh/cap/yr kWh/cap/yr kWh/cap/yr kWh/cap/yr kWh/cap/yr kWh/cap/yr kWh/cap/yr kWh/cap/yr kWh/cap/yr kg/cap/yr kg/cap/yr kg/cap/yr kg/cap/yr l/cap/day
317 2155 788 586 565 208 7.84 10,149 345 8255 0.97 1548 2660 234 93 2333 157
324 2419 855 603 750 204 6.59 12,087 1070 8393 52.32 2572 4172 359 137 3676 162
2 12 8 3 33 2 16 19 210 2 5316 66 57 53 48 58 3
IBGE
SNIC/CBIC IABr ANEPAC, DNPM SANEPAR
kg/cap/yr kg/cap/yr kg/cap/yr kg/cap/yr kg/cap/yr kg/cap/yr l/cap/day t-CO2eq/cap/yr
443 335 83 2.40 4.6 17 101 2.00
416 264 110 1.54 4.8 35 142 2.01
6 21 33 36 6 101 40 0
PMC, IPPUC PMC, IPPUC PMC, IPPUC PMC, IPPUC PMC, IPPUC SANEPAR ECOWOOD, 2008
COPEL, COPEL, COPEL, COPEL, COPEL,
IPPUC IPPUC IPPUC IPPUC IPPUC
COPEL ANP COPEL COPEL
Table 3 Selected indicators for livability and quality of services. Indicator Livability Population Fleet Employment (people employed/EAP)a Formal education (Literate over 15 yrs) Under-five mortality rate (per 1000 births) Violent deaths (100,000 population) Transport fatalities (100,000 population) Monthly average income Gini coefficient Educational attainment Quality of service Population with access to internetb Population with mobile phonesb Households without direct access to water Households without sewagec Wastewater subject to treatment Households without public waste collection Households without grid electricity connectionc
Unit
2000
2010
%
Source
Inhabitants veh/cap % % ratio ratio ratio US$/cap index avrg. yrs.
1,587,315 0.42 85.9 96.6 17.5 21.1 26.8 624 0.59 7.3
1,751,907 0.68 95.1 97.9 10.2 43.5 17.9 922 0.57 8.3
10 62 11 1 42 106 33 48 3 14
IBGE DETRAN IBGE IBGE SESA SESA SESA IBGE IBGE IBGE
% % % % % % %
20.15 54.47 0.27 1.71 80.91 0.7 0.63
52.90 92.22 0.10 0.62 98.71 0.0 0.05
163 69 63 64 22 n/a 92
IBGE IBGE IBGE IBGE SANEPAR SNIS IBGE
Notes. a Economically active population. b Data available from 2003 to 2011. c Data available from 2001 to 2011.
as there was no lack of jobs in Brazil. A greater number of people spent more time in school, which reduced the amount of persons looking for jobs and delayed their entrance in the job market. There was an important reduction in under-five mortality (49%) and life expectancy went from 70 years old (2000) to about 74 (2010). In education, although literacy is among the best values considering cities in corresponding countries (Russia e 99.7% and China e 95.1%) and the value of 97.9% represents high human development, average years spent in formal education (8.3) still lower than in countries like US and Germany (12.9 years), Sweden and Russia (11.7 years) and Chile and Argentina (9.6 years) (UNDP, 2010).
The number of vehicles almost doubled (þ78%), consequence of incentives for the auto industry as well as gain in purchasing power. At the same time, the rate of transport fatalities decreased (33%), even though the gross number of deaths stood elevated (314). Other issues observed are similar to those found in the whole country, especially in big urban centers; they concern unequal wealth distribution and the consequent violence, which represents an attempt to informally balance this disparity. The Gini coefficient, which measures such distribution, has barely changed over ten years (0.59e0.57), indicating that the wealth produced kept concentrated. Meanwhile, violent deaths rose (106%), exposing one
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of the worst problems faced in Brazil. Utilities services are more available: almost all households have access to water (99.90%) and to electricity (99.95%). Public Administration, that controls energy and water companies, expanded infrastructure, and now 99.38% of households have access to sewage. Public waste collection was always exemplary and now serves the entire city, but local administration keeps investing in recycling programs and environmental education. Mobile phones and access to internet grew in admirable rates (69% and 163%, respectively), but the latter has not yet met the expected level. 5. Conclusions Data analysis provided an overview of the urban metabolism of Curitiba in 2000 and 2010. Similarly to other cities in Brazil, we noticed an improvement in quality of life due to higher resource use as well as higher waste generation. When compared to other cities in developed or developing countries, Curitiba's metabolism reveals inferior per capita material and energy use. On the one hand, it shows the potential for an even greater enrichment of living conditions; on the other hand, it reminds that the social and economic expansion implies in more degradation and pollution, and it must be carried out without disregard to environmental preservation. In order to achieve this balance, it will be necessary to face emerging challenges such as the unplanned growth of the territory due to illegal land occupation; the lack of legislation that properly includes ecological services into account; the focus on palliative solutions instead of long-term planning and; budget limitations, influenced by Brazilian economic cycles. As shown by urban metabolism studies, it is difficult (if not impossible) to find cities e especially big industrialized ones e that are self-sufficient. Comparison between Curitiba's production and consumption of resources (food, construction materials, energy etc.) suggest that the city is not capable of producing everything it consumes, and does not have the adequate amount of space to dispose its waste. In order to maintain its sustainability, it uses (directly or indirectly) land spaces beyond its administrative limit, disassociating its ecological location from its geographical location (Steinberger, 2001; Rees and Wackernagel, 1996). This analysis reinforces the problem previously mentioned by Wolman (1965), about the difficulty in completely describing the urban metabolism of a city, due to intense, complex and geographically dispersed economic interactions. The levels of commerce and globalization impede the correct observation of the city's own metabolism, as the demands of natural space will be supplied by other regions, making the environmental impact less visible (Rees and Wackernagel, 1996). Accepting that cities are going farther to acquire the resources needed to survive should change the debate over urban sustainability, as they should be accountable for the transference of environmental costs to other spaces (geographical regions), time (future challenges) and people (next generations). Consequently, it does not seem adequate to try to evaluate if one single city is sustainable or not, but instead, to understand its contribution to sustainable development. This contribution would depend on the production methods, consumption patterns and disposal amounts, as well as the level of well-being and opportunities created. Wachsmuth (2012, p. 515) then argues that problems in the city are not necessarily problems of the city. And he raises the question: “why should we look for municipal solutions to the pathologies of urban metabolism when the environmental pressures are universally understood to be regional or indeed planetary?” The case of Curitiba, for instance, helps illustrate the potential and the necessity of regional solutions to urban sustainability. Nowadays, the
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main landfill is located in the metropolitan area (32 km far from downtown), provoking higher costs, obstacles in logistics and an environmental burden. In order to overcome this challenge, the city conceived in 2007, an integrated waste management program (collection, separation, recycling and discharge) with other 21 cities located in the metropolitan area, following the successful experience with public transportation. Curiously, despite strong social concern with correct waste disposal, the project has not been implemented yet, due mainly to the lack of an adequate space for the landfill, disputes over the types of treatments available, disagreement about cost sharing and deficiency in basic contracts and legal requirements. For Curitiba (and any other city that supposedly take sustainability seriously), the need for continuous development should be considered together with the consequent environmental impact, both well measured by the urban metabolism approach. This evaluation of the production and consumption of resources and the generation of waste should be a mainstream activity that would surely help urban planning, design and decision-making. In future studies, besides monitoring the metabolic flow, there should be an analysis of the distribution of materials and energy within the city, which may reveal inequalities in use in different areas. Despite the challenges to deal with the balance between development and preservation, cities must be always aware of their contribution to sustainability, in order to prevent ecological and environmental problems from advancing faster than their solutions. Acknowledgements The authors would like to thank Oli Negrelle, Erlete Teresa and Marcio Silveira for their support during the development of this research. They also thank the reviewers for their valuable comments. References ber, A.N., 2004. A sociedade urbano-industrial e o metabolismo urbano (Urab'Sa ban-industrial Society and Urban Metabolism). Coleç~ ao Princípios 71, 54e57. Alberti, M., Marzluff, J.M., Shulenberger, E., Bradley, G., Ryan, C., Zumbrunnen, C., 2003. Integrating humans into ecology: opportunities and challenges for studying urban ecosystems. Bioscience 53 (12), 1169e1179. Bolund, P., Hunhammar, S., 1999. Ecosystem services in urban areas. Ecol. Econ. 29 (2), 293e301. Brunner, P.H., 2007. Reshaping urban metabolism. J. Ind. Ecol. 11 (2), 11e13. Burgess, E.W., 1925. The growth of the city: an introduction to a research project. chapter II. In: Park, R.E., Burgess, E.W., McKenzie, R.D. (Eds.), The City. The University of Chicago Press, Chicago, pp. 47e62. Goodland, R., Daly, H., 1996. Environmental sustainability: universal and nonnegotiable. Ecol. Appl. 6 (4), 1002e1017. Holmes, T., Pincetl, S., 2012. Urban Metabolism Literature Review. UCLA. Institute of the Environment and Sustainability. Center for Sustainable Urban Systems, Los Angeles. http://www.environment.ucla.edu/media/files/Urban-MetabolismLiterature-Review2012-44-fea.pdf (accessed May 2014). Hoornweg, D., Campillo, G., Saldivar-Sali, A.N., Linders, D., Sugar, L., 2012. Mainstreaming urban metabolism: advances and challenges in city participation. In: Sixth Urban Research and Knowledge Symposium 2012 (accessed May 2014). www.dennislinders.com/portfolio/Hoornweg_et_al_URKS6_Urban_ Metabolism.pdf. IWM. Chartered Institution of Wastes Management Environmental Body, 2002. City Limits: a Resource Flow and Ecological Footprint Analysis of Greater London. Best Foot Forward Ltd.. http://www.citylimitslondon.com/downloads/Complete %20report.pdf Kennedy, C., Hoornweg, D., 2012. Mainstreaming urban metabolism. J. Ind. Ecol. 16 (6), 780e782. Kennedy, C., Ibrahim, N., Stewart, I., Facchini, A., Mele, R., 2014. An Urban Metabolism Survey Design for Megacities. Enel Foundation/University of Toronto (accessed May 2014). http://www.enel.com/en-GB/enel_foundation/library/ working_papers/2014/. Kennedy, C., Pincetl, S., Bunje, P., 2011. The study of urban metabolism and its applications to urban planning and design. Environ. Pollut. 159, 1965e1973. Kennedy, C.A., Cuddihy, J., Engel Yan, J., 2007. The changing metabolism of cities. J. Ind. Ecol. 11 (2), 43e59. Medeiros, E.B., 1975. O lazer no planejamento urbano (Leisure in Urban Planning). FGV, Rio de Janeiro.
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Moore, J., Kissinger, M., Rees, W.E., 2013. An urban metabolism and ecological footprint assessment of Metro Vancouver. J. Environ. Manage. 124, 51e61. Newman, P., 1999. Sustainability and cities: extending the metabolism model. Landsc. Urban Plan. 44 (4), 219e226. PMC, 2014. Prefeitura Municipal de Curitiba. Curitiba Urban Administration. www. curitiba.pr.gov.br (accessed May 2014). , E., 2009. Urban metabolism: the case of Budapest. In: Pom azi, I., Szabo nek, M. (Ed.), Urban Metabolism: Measuring the Ecological City. Charles Havra University Environment Center, Prague, pp. 10e28. Proceedings of a ConAccount workshop. Rees, W., Wackernagel, M., 1996. Urban ecological footprints: why cities cannot Be sustainable e and why they are a key to sustainability. Environ. Impact Assess. Rev. 16, 223e248. Singh, V.S., Pandey, D.N., Chaudhry, P., 2010. Urban Forests and Open Green Spaces: Lessons for Jaipur, Rajasthan, India. Rajasthan State Pollution Control Board. RSPCB_ Occasional Paper No. 1. Steinberger, M.A., 2001. (Re) Construç~ ao de Mitos: sobre a (In) Sustentabilidade do Espaço Urbano ((Re) Thinking Myths about Urban (Un) Sustainability). Rev. Bras. Estud. Urbanos Reg. 3 (4), 9e32. UNDP. 2010. United Nations Development Programme. Human Development Reports. (accessed April 2014). http://hdr.undp.org/en/data. Wachsmuth, D., 2012. Three Ecologies: urban metabolism and the society-nature opposition. Sociol. Q. 53 (4), 506e523. Wolman, A., 1965. The metabolism of cities. Sci. Am. 213 (3), 179e190. Zhang, Y., Zhifeng, Y., 2007. Eco-efficiency of urban material metabolism: a case study in Shenzhen, China. Acta Ecol. Sin. 27 (8), 3124e3131.
Web References and Statistical Sources ~o Nacional das Entidades de Produtores de Agregados para ANEPAC. Associaça ~o Civil. [Nacional Association of Civil Construction Aggregates ProConstruça ducers]. http://www.anepac.org.br/wp/. ^ncia Nacional de Petro leo, Ga s Natural e Biocombustíveis. [National Agency ANP. Age of Petroleum, Natural Gas and Biofuels]. www.anp.gov.br. ^mara Brasileira da Indústria da Construça ~o. [Brazilian Chamber of ConCBIC. Ca struction Industry]. http://www.cbic.org.br/. COPEL. Companhia Paranaense de Energia. [State Energy Company]. Balanço
tico do Parana : 2000 and 2010. [State Energetic Yearbook: 2000 and Energe 2010]. Accessed February 2014. http://www.copel.com/hpcopel/acopel/balanco. jsp. ^nsito do Parana . [State Traffic Department]. www. DETRAN. Departamento de Tra detran.pr.gov.br. ~o Mineral. [National Department of DNPM. Departamento Nacional de Produça rio Mineral Brasileiro: 2000 and 2010. [Brazilian Mineral Production]. Anua Mineral Yearbook: 2000 and 2010]. http://www.dnpm.gov.br/conteudo.asp? IDSecao¼68&IDPagina¼66. Accessed April 2014. rio e balanço de emisso ~es de GEE em Curitiba (Inventory ECOWOOD, 2008. Inventa and balance of GHG emissions in Curitiba) (accessed May 2014). http://www. curitiba.pr.gov.br/multimidia/00118446.pdf. IABr. Instituto Aço Brazil. [Brazilian Steel Institute]. www.acobrasil.org.br. . [State Environmental Institute]. Relato rio de IAP. Instituto Ambiental do Parana qualidade do ar: 2000 e 2010. [Air quality Report: 2000 and 2010]. accessed March 2014. http://www.iap.pr.gov.br/modules/conteudo/conteudo.php? conteudo¼639. IBGE. Instituto Brasileiro de Geografia e Estatística. [Brazilian Institute of Geography and Statistics]. www.ibge.gov.br. INMET, 2014. Instituto Nacional de Meteorologia (National Institute of Meteorology) (accessed July 2014). www.inmet.gov.br. ^mico e Social. [State IPARDES. Instituto Paranaense de Desenvolvimento Econo Institute of Social and Economic Development]. www.ipardes.gov.br. IPPUC. Instituto de Pesquisa e Planejamento Urbano de Curitiba. [Institute of Urban Research and Management of Curitiba]. www.ippuc.org.br. Olivier, J.G.J., Janssens-Maenhout, G., Peters, J.A.H.W., 2012. Trends in Global CO2 Emissions: 2012 Report. PBL Netherlands Environmental Assessment Agency, The Hague, The Netherlands. www.pbl.nl/en. . [Parana State Water Company]. SANEPAR. Companhia de Saneamento do Parana www.sanepar.com.br. SESA. Secretaria de Saúde do Paran a. [Paran a State Health Office]. www.saude.pr. gov.br. SNIC. Sindicato Nacional da Indústria do Cimento. [National Association of Cement Industries]. www.snic.org.br. ~ es sobre Saneamento. [National Database of SNIS. Sistema Nacional de Informaço Sanitation Information]. www.snis.gov.br. WSA. World Steel Association. www.worldsteel.org.
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Environmental Pollution journal homepage: www.elsevier.com/locate/envpol
Urban metabolism: Measuring the city's contribution to sustainable development L. Ferreira Leonardo S. Conke*, Taina Sustainable Development Center, University of Brasília, Brazil
a r t i c l e i n f o
a b s t r a c t
Article history: Received 6 November 2014 Received in revised form 19 March 2015 Accepted 21 March 2015 Available online
Urban metabolism refers to the assessment of the amount of resources produced and consumed by urban ecosystems. It has become an important tool to understand how the development of one city causes impacts to the local and regional environment and to support a more sustainable urban design and planning. Therefore, the purpose of this paper was to measure the changes in material and energy use occurred in the city of Curitiba (Brazil) between the years of 2000 and 2010. Results reveal better living conditions and socioeconomic improvements derived from higher resource throughput but without complete disregard to environmental issues. Food intake, water consumption and air emissions remained at similar levels; energy use, construction materials and recycled waste were increased. The paper helps illustrate why it seems more adequate to assess the contribution a city makes to sustainable development than to evaluate if one single city is sustainable or not. © 2015 Elsevier Ltd. All rights reserved.
Keywords: Urban metabolism Urban sustainability Industrial ecology
1. Introduction Among the many challenges concerning sustainable development, one that deserves special attention is urban sustainability. The difficulty in balancing quality of life and preservation of natural resources is evident in urban areas, where expectations about the availability of employment, housing and culture exist together with hopes for pure air, mental and physical health and contact with nature. In these dominated and occupied landscapes, humans reorganize and redistribute resources in order to create opportunities, changing the functioning of ecosystems and causing environmental problems (Alberti et al., 2003). The study of urban sustainability can be carried out through different perspectives. One that has been recognized as adequate and consistent compares the city to an ecosystem or an organism, having inputs, transformation and outputs of material and energy, i.e., a metabolism. It assumes that the maintenance of life involves the conversion of natural resources in goods, services and waste. The first time that this idea was related to an urban system was in the early 1920s, with Burgess (1925). However, the landmark paper of Urban Metabolism was developed by Abel Wolman in 1965,
* Corresponding author. Postal address: Universidade de Brasília, Campus Unirio Darcy Ribeiro, Faculdade de Administraça ~o, Contabilidade e Economia, versita Brasília, 70910-900 DF, Brazil. E-mail address: [email protected] (L.S. Conke). http://dx.doi.org/10.1016/j.envpol.2015.03.027 0269-7491/© 2015 Elsevier Ltd. All rights reserved.
when he studied the impacts of material consumption and waste generation of a hypothetical American city of one million people. Urban metabolism can be understood as “the sum total of the technical and socioeconomic processes that occur in cities, resulting in growth, production of energy, and elimination of waste” (Kennedy et al., 2007). If we assume that sustainable development is the “development without increases in the throughput of materials and energy beyond the biosphere's capacity for regeneration and waste assimilation” (Goodland and Daly, 1996), then the urban metabolism approach represents a comprehensive framework that helps monitor the transformation occurring in cities, as well as their contributions to sustainable development (Hoornweg et al., 2012). Studying the flows of materials and energy throughout a city became (more) useful when human activities started affecting the ber, 2004). If city natural cycles of other living organisms (ab'Sa growth is achieved by increased resource throughput, then environmental issues and economic costs depend on the management of the inputs and outputs of material and energy that takes place in urban spaces (Newman, 1999). Unsustainable metabolic processes can cause the exhaustion of resources, impacting the environment in local and regional scale and turning the relationship between urban growth and natural space into a real problem. According to Kennedy et al. (2011), an urban metabolism analysis serves four main purposes: the first one is related to the assessment of materials and energy flows throughout a city. It is a
L.S. Conke, T.L. Ferreira / Environmental Pollution 202 (2015) 146e152
basic accounting effort that can provide scientifically valid and representative data for urban planning. The resultant evaluation shows the efficiency in resource use, its future need, the existence of any environmental burden, the contribution of recycling and the capacity of waste treatment, enabling a better awareness of how much impact human activity (social, economic and political) is causing in the natural environment (Brunner, 2007; Holmes and Pincetl, 2012). The second application aims to quantify greenhouse gas (GHG) emissions, a metric which is part of urban metabolism itself, but it turned into an independent contribution due to its relationship to climate change. Third and fourth applications use material and energy evaluation to support decisions concerning public policy. In order to deal with problems such as pollution, sewage treatment, resource scarcity, water shortage and the formation of heat islands, different options in urban design are assessed with the aid of mathematical models, which shows the choices that best balance greater social and economic advancements with lower ecological effects (Kennedy and Hoornweg, 2012; Hoornweg et al., 2012). Therefore, considering the growing relevance of urban metabolism studies, the purpose of this paper is to measure the changes in material and energy use occurred in Curitiba (Brazil) in the decade of 2000e2010. The gathering of data regarding this city's flows of materials and energy in ten years represents the first step to a more sophisticated analysis, and will hopefully support planning and decision-making regarding its sustainability. Besides the accounting contribution, the paper expands the comprehension of the relationship between urban regions, highlighting how industrialized cities are now more dependent on the land space available (only) beyond its geographical limits.
147
methodological obstacle. They represent a more integrative approach where social and economic aspects can be examined in the context of urban metabolism (Kennedy et al., 2014). Although urban metabolism studies have evolved over the years, some difficulties persist. The main ones, as anticipated by Wolman (1965), involve data availability and the gathering of information. One reason is that it is actually impossible to completely evaluate any urban metabolism (Brunner, 2007), as cities are present in global markets and their sustainability depend on resources available elsewhere; thus, a metabolic analysis would only be complete if it was able to identify this complex inter-municipal relationship, with the entire description of the origins and destinations of resources, produced goods and waste. In some cases, data available for the local level is less reliable than for the national level, as international transactions are better controlled (Kennedy et al., 2007; Hoornweg et al., 2012). Another challenge is to increase proficiency in data collection and management. Hoornweg et al. (2012) advises that “data is very fragmented and not regularly collected and the studies very much adopted a ‘best available data’ approach”. Even though Curitiba has a fairly decent official database, quality in reporting and even a department that control statistics, data was still dispersed and its gathering demanded more effort than it should be necessary. Nonetheless, we were able to contribute with a satisfactory overview of how the city has changed its resource consumption and waste production. Also, the ten-year approach represents a step further in usual urban metabolism studies, that due to (not) available data and (not) continuous monitoring, generally show only one moment (one year), reducing the possibility of comparison. 3. Case study
2. Methods Developed over the years, urban metabolism methodology is nowadays sufficiently robust, consistent and well anchored in existing academic literature. Integrated frameworks allow the examination of energy and material flows in complex systems, shaped by various social, economic and environmental forces (Holmes and Pincetl, 2012). The specific framework adopted to assess the urban metabolism of Curitiba was proposed by Kennedy and Hoornweg (2012). They presented the basic data that should be collected in any attempt to evaluate the urban metabolism of one city or region. Requirements for Abbreviated Urban Metabolism Studies refer to inflows (water, construction materials, fossil fuels, electricity etc.) production (food, wood etc.), stocks (minerals, nutrients etc.) and outflows (air emissions, wastewater and solid waste). One of the contributions of this model is the possibility of comparison between different locations around the world, as the essential indicators are suggested along with standardized measuring units. Considering that the main purposes are to provide a quantitative measure of Curitiba's material and energy flow and to understand the city social and economic transformation in ten years, we also included in the analysis some of the variables from the works of Newman (1999) and Kennedy et al. (2014). Newman (1999) is known for extending the metabolism model, in one of the first efforts to add social issues to urban studies, showing how resources are being used to create opportunities. He introduced variables about settlement dynamics and livability, which should be fully integrated in urban metabolism studies (Kennedy et al., 2011). Kennedy et al. (2014) used the Abbreviated Urban Metabolism framework to measure and compare almost 15 megacities. They added parameters to describe how the basic infrastructure and the services offered for households can improve living conditions in the city, reinforcing the need to measure social matters. These adjustments were considered appropriate and did not represent any
Curitiba is located in the south portion of Brazil, and it is the (see Fig. 1). Officially administrative capital of the state of Parana founded in March 29th, 1693, it was first dedicated to mining, agriculture and livestock in the 17th century. Later, with the arrival of several groups of immigrants and the building of railroads connecting it to the sea, Curitiba became one of the biggest industrial production areas of the state. Nowadays, population is about 1.8 million people (the 8th most populated city in Brazil) and population density is 4027 inhabitants/km2. Regarding its economy, Curitiba raised its Gross Domestic Product (GDP) from US$ 8 billion ~o Paulo, Rio de (2000) to about US$ 32 billion (2010), following Sa Janeiro and Brasília as the 4th biggest GDP of Brazil. In the social level, the Human Development Index (HDI) went from 0.750 to 0.823 in the same period, ranking 10th in Brazil (PMC, 2014; IBGE). Curitiba has a land area of about 435 km2 and is located 945m above sea level. With a typical subtropical climate, the average temperature is 21 C in the summer and 13 C in the winter, rather cold for Brazil. The annual solar radiation in Curitiba (1481 kWh/ ~o Paulo (1622 kWh/m2) and Rio de Janeiro m2) is below cities like Sa (1694 kWh/m2) and the average annual precipitation is about 1400 mm (Hoornweg et al., 2012; PMC, 2014; INMET, 2014). Similarly to the whole state, the main biome in Curitiba is the Atlantic Forest, and the city itself is served with 29 parks and 115 million m2 of green areas, which makes an average of 64.5 square meters per capita (m2/cap), above the recommended standard of 40 m2/cap (Medeiros, 1975; Singh et al., 2010). At the same time, the building gross floor area is about 92 million m2, being 69% of residential areas and 31% of non-residential areas. We chose to study the urban metabolism of Curitiba for some reasons. First, the city is widely recognized for its efforts concerning sustainability. In the 1970s, instead of using vacant land to real estate speculation, the option was to create new parks and green areas, an alternative better suited for ecological preservation and
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Fig. 1. Location of Curitiba (city) and Parana (state) in Brazil. Source: IPPUC, IPARDES, IBGE.
population well-being (PMC, 2014). From 1989 to 2004, three consecutive administrations made important changes in urban architecture, public transportation and waste management, planning the city with special attention to the environment. Nevertheless, after this period, Curitiba experienced the same economic and social transition that happened throughout the whole country: an increase of employment and revenue along with an aggravation of violence, traffic and pollution. Hence, the idea was to identify through material and energy flows, if a city known for its dedication to green issues is able to profit from the benefits associate to economic and social growth without worsening problems such as pollution, loss of biodiversity and natural degradation. The second reason is that there appears to be a lack of urban metabolism studies in Latin American cities. In a chronological review, Kennedy et al. (2011) found a total of 36 studies, where none was from a South or Latin American city. One of the first initiatives was found in Hoornweg et al. (2012), with a preliminary assessment of Sao Paulo and Rio de Janeiro in Brazil, and Buenos Aires in Argentina, among other cities in Asia and Africa. Sao Paulo and Rio de Janeiro were again considered among other megacities around the world to be part of the urban metabolism project carried out by Kennedy et al. (2014). Thus, we find it appropriate to expand urban metabolism studies to other big cities, especially in developing countries like Brazil. Understanding the metabolic processes in these countries is relevant because they are (now) also accounted for the responsibilities of natural preservation and GHG mitigation and the need to develop without neglecting environmental issues became more noticeable in such regions. 4. Results Tables 1e3 summarize the Urban Metabolism of Curitiba in 2000 and 2010. Tables 1 and 2 present, respectively, gross and per capita volume of materials and energy consumed and produced in the city, as well as its variation in ten years. In Table 3, selected indicators reveal the livability and the quality of services provided in Curitiba.
Regarding material inputs, Curitiba has shown a slight increase in the total food intake (13%); yet, per capita food intake had almost is the no gain (2%). It is relevant to point out that the state of Parana first in grain production in Brazil, especially soybean and corn. Nonetheless, a completely urban area and without rural households, Curitiba's food, wood and mineral production is minimal, and it has decreased over the years, making the dependency on other external resources more noticeable. Well served by rivers, Curitiba was able to maintain its level of water consumption of about 160 daily liters per capita. Investments made in infrastructure helped spread access to drinkable water to a number of households located outside the center area e only 0.10% of households were without access in 2010. Consumption is below other large cities as S~ ao Paulo (197 l/cap/day) or Rio de Janeiro (292 l/cap/day), which have greater industrial activity and higher temperatures (Hoornweg et al., 2012). However, per capita water consumption in all these cities is inferior to other places in developed countries as Vancouver, Canada (554 l/cap/day) (Moore et al., 2013) and London, England (324 l/cap/day) (IWM, 2002), or even in developing countries as Shenzhen, China (734 l/cap/day) (Zhang and Zhifeng, 2007). Data found also reveals some trends in electricity and energy use. The commercial sector had the greatest increase in electricity use (46%). Apparently, industry adopted other types of energy sources, as natural gas (þ243%) and coal (þ5878%). Even though fossil fuels still represent the most used type of energy, it had the least gain (12%), which will (eventually) help slowing down GHG emissions. Along with energy, the city consumed more construction materials (þ57%). For instance, per capita construction material use was similar to London (3757 kg/cap/yr) (IWM, 2002). This is probably due to the vertiginous growth of the real estate market, which had its peak in 2010, with more than 33,500 construction permits approved. Farm land, formerly used for (family) agriculture had been employed for building, in order to accommodate real estate demands in the city. The results of the economic expansion can be observed in the
L.S. Conke, T.L. Ferreira / Environmental Pollution 202 (2015) 146e152
149
Table 1 Urban metabolism of Curitiba e gross value. Material Category Inputs Food intakea Electricity consumption (total) Residential Industrial Commercial Public Services Other Energy consumption (total) Natural gas Fossil fuelsb Coal (mineral þ vegetable) Biomass/biofuels Construction materials (use) Cement Steel Aggregates (sand, gravel) Water consumption Production Food Wood Construction materials Cement Steel Minerals (clay, gold, crushed stones) Water production (surface water) Stocks Minerals (clay, gold, crushed stones) Landfill waste (accumulated) Outputs Municipal solid waste Domestic and public waste Recyclable waste Healthcare waste Toxic waste Tree and junk waste Wastewater GHG emissionsd Air emissions Total suspended particulate (TSP) Smoke Inhalable particles Sulfur dioxide (SO2) Nitrogen dioxide (NO2)
Unit
2000
2010
%
Source
ton GW/h GW/h GW/h GW/h GW/h GW/h TJ TJ TJ TJ TJ ton ton ton ton ML
503,535 3423 1251 931 897 332 12 58,010 1969 47,184 6 8851 4,221,841 371,432 146,985 3,703,424 90,906
567,457 4239 1498 1057 1314 358 12 76,255 6748 52,949 330 16,228 7,308,036 628,935 239,836 6,439,265 103,529
13 24 20 14 46 8 7 32 243 12 5878 83 73 69 63 74 14
IBGE
ton m3 ton ton ton ton ML
2394 4,110c 940,993 680,506 260,487 30,368 162,771
1303 2738 1,256,202 953,570 302,632 15,173 169,086
46 33 33 40 16 50 4
SNIC, CBIC WSA DNPM SANEPAR, SNIS
ton ton
1,427,256 3,607,122
560,409 8,711,683
61 142
DNPM PMC, IPPUC
ton ton ton ton ton ton ML t-CO2eq mg/m3 mg/m3 mg/m3 mg/m3 mg/m3 mg/m3
702,974 532,135 132,173 3807 7286 27,573 58,594 3,174,630 158 86 22 15 11 24
728,453 462,587 193,470 2704 8495 61,197 90,486 3,515,890 107 36 16 27 3 25
4 13 46 29 17 122 54 11 32 58 29 79 71 3
COPEL, COPEL, COPEL, COPEL, COPEL,
IPPUC IPPUC IPPUC IPPUC IPPUC
COPEL ANP COPEL COPEL SNIC, CBIC IABr ANEPAC, DNPM SANEPAR IBGE, PMC IBGE
PMC, IPPUC PMC, IPPUC PMC, IPPUC PMC, IPPUC PMC, IPPUC SANEPAR, SNIS ECOWOOD IAP IAP IAP IAP IAP
Notes. a Available reliable data for the years 2002 and 2009. b Diesel oil, fuel oil, gasoline, aviation fuel, liquefied Petroleum gas and kerosene oil. c Data from 2004. d The only local GHG inventory made in Curitiba dates from 2008, number used in the column of 2010; for the 2000 calculation, the source was Olivier et al. (2012).
material outflow data, especially on the larger generation of wastewater (54%). The city extended the infrastructure, leaving only 0.62% of the households without sewage treatment. The amount of solid waste per capita produced decreased 6% along with a raise of 33% in the recyclable waste. Comparing to a city with similar population as Budapest (1.7 million people), domestic waste discharged in 2010 was almost half, being 335 kg/yr against 630 kg/ zi and Szabo , 2009). These specific yr of the Hungarian city (Poma results are due to Curitiba's long-time focus on selective collection, being one of the best examples in Brazil. Since 1989, local administration has reinforced the need for recycling and supported continuous programs to maintain domestic and industrial waste separation; the urban metabolism data reveal the efficacy of such investments. Air emissions have dropped 32% in ten years, despite industrial expansion. Excluding the bigger amount of inhalable particles, most components showed descent in the period analyzed. According to local administration, the particles are within acceptable standards, even though it is necessary to improve measurement
techniques and equipment. GHG emissions still close to Brazilian average (2.2 ton cap/year), but way below cities in other developing countries as Russia (12.2 ton cap/year), South Africa (9.2 ton cap/ year) and China (6.2 ton cap/year) (UNDP, 2010). Among the reasons, there is the preservation of the several open spaces, parks and green areas existent in Curitiba, which provide ecosystem services such as air filtration, rainwater drainage and micro climate regulation (Bolund and Hunhammar, 1999). Furthermore, most of Curitiba's electrical supply comes from the hydroelectric power plant of Itaipu, a rather clean energy source. Finally, the excessive number of automobiles and the quality of the public transportation system has reinforced the use of buses and bicycles within the city. Data on livability and on quality of services helps understand the changes between 2000 and 2010 (Table 3), and this variation is reflected in the amount of materials and energy used. Almost all indicators of Curitiba's livability moved upward, showing social improvement; nevertheless, they remain below recommended levels. Employment and income were congruent to national patterns,
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Table 2 Urban metabolism of Curitiba e Per capita value. Material category
Unit
2000
2010
%
Source
Population Inputs Food intake Electricity consumption Residential Industrial Commercial Public services Other Energy consumption Natural gas Fossil fuels Coal (mineral þ vegetable) Biomass/biofuels Construction materials (use) Cement Steel Aggregates (sand, gravel) Water consumption Outputs Solid waste Domestic and public waste Recyclable waste Healthcare waste Toxic waste Tree and junk waste Sewage GHG emissions
Inhabitants
1,587,315
1,751,907
10
IBGE
kg/cap/yr kWh/cap/yr kWh/cap/yr kWh/cap/yr kWh/cap/yr kWh/cap/yr kWh/cap/yr kWh/cap/yr kWh/cap/yr kWh/cap/yr kWh/cap/yr kWh/cap/yr kg/cap/yr kg/cap/yr kg/cap/yr kg/cap/yr l/cap/day
317 2155 788 586 565 208 7.84 10,149 345 8255 0.97 1548 2660 234 93 2333 157
324 2419 855 603 750 204 6.59 12,087 1070 8393 52.32 2572 4172 359 137 3676 162
2 12 8 3 33 2 16 19 210 2 5316 66 57 53 48 58 3
IBGE
SNIC/CBIC IABr ANEPAC, DNPM SANEPAR
kg/cap/yr kg/cap/yr kg/cap/yr kg/cap/yr kg/cap/yr kg/cap/yr l/cap/day t-CO2eq/cap/yr
443 335 83 2.40 4.6 17 101 2.00
416 264 110 1.54 4.8 35 142 2.01
6 21 33 36 6 101 40 0
PMC, IPPUC PMC, IPPUC PMC, IPPUC PMC, IPPUC PMC, IPPUC SANEPAR ECOWOOD, 2008
COPEL, COPEL, COPEL, COPEL, COPEL,
IPPUC IPPUC IPPUC IPPUC IPPUC
COPEL ANP COPEL COPEL
Table 3 Selected indicators for livability and quality of services. Indicator Livability Population Fleet Employment (people employed/EAP)a Formal education (Literate over 15 yrs) Under-five mortality rate (per 1000 births) Violent deaths (100,000 population) Transport fatalities (100,000 population) Monthly average income Gini coefficient Educational attainment Quality of service Population with access to internetb Population with mobile phonesb Households without direct access to water Households without sewagec Wastewater subject to treatment Households without public waste collection Households without grid electricity connectionc
Unit
2000
2010
%
Source
Inhabitants veh/cap % % ratio ratio ratio US$/cap index avrg. yrs.
1,587,315 0.42 85.9 96.6 17.5 21.1 26.8 624 0.59 7.3
1,751,907 0.68 95.1 97.9 10.2 43.5 17.9 922 0.57 8.3
10 62 11 1 42 106 33 48 3 14
IBGE DETRAN IBGE IBGE SESA SESA SESA IBGE IBGE IBGE
% % % % % % %
20.15 54.47 0.27 1.71 80.91 0.7 0.63
52.90 92.22 0.10 0.62 98.71 0.0 0.05
163 69 63 64 22 n/a 92
IBGE IBGE IBGE IBGE SANEPAR SNIS IBGE
Notes. a Economically active population. b Data available from 2003 to 2011. c Data available from 2001 to 2011.
as there was no lack of jobs in Brazil. A greater number of people spent more time in school, which reduced the amount of persons looking for jobs and delayed their entrance in the job market. There was an important reduction in under-five mortality (49%) and life expectancy went from 70 years old (2000) to about 74 (2010). In education, although literacy is among the best values considering cities in corresponding countries (Russia e 99.7% and China e 95.1%) and the value of 97.9% represents high human development, average years spent in formal education (8.3) still lower than in countries like US and Germany (12.9 years), Sweden and Russia (11.7 years) and Chile and Argentina (9.6 years) (UNDP, 2010).
The number of vehicles almost doubled (þ78%), consequence of incentives for the auto industry as well as gain in purchasing power. At the same time, the rate of transport fatalities decreased (33%), even though the gross number of deaths stood elevated (314). Other issues observed are similar to those found in the whole country, especially in big urban centers; they concern unequal wealth distribution and the consequent violence, which represents an attempt to informally balance this disparity. The Gini coefficient, which measures such distribution, has barely changed over ten years (0.59e0.57), indicating that the wealth produced kept concentrated. Meanwhile, violent deaths rose (106%), exposing one
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of the worst problems faced in Brazil. Utilities services are more available: almost all households have access to water (99.90%) and to electricity (99.95%). Public Administration, that controls energy and water companies, expanded infrastructure, and now 99.38% of households have access to sewage. Public waste collection was always exemplary and now serves the entire city, but local administration keeps investing in recycling programs and environmental education. Mobile phones and access to internet grew in admirable rates (69% and 163%, respectively), but the latter has not yet met the expected level. 5. Conclusions Data analysis provided an overview of the urban metabolism of Curitiba in 2000 and 2010. Similarly to other cities in Brazil, we noticed an improvement in quality of life due to higher resource use as well as higher waste generation. When compared to other cities in developed or developing countries, Curitiba's metabolism reveals inferior per capita material and energy use. On the one hand, it shows the potential for an even greater enrichment of living conditions; on the other hand, it reminds that the social and economic expansion implies in more degradation and pollution, and it must be carried out without disregard to environmental preservation. In order to achieve this balance, it will be necessary to face emerging challenges such as the unplanned growth of the territory due to illegal land occupation; the lack of legislation that properly includes ecological services into account; the focus on palliative solutions instead of long-term planning and; budget limitations, influenced by Brazilian economic cycles. As shown by urban metabolism studies, it is difficult (if not impossible) to find cities e especially big industrialized ones e that are self-sufficient. Comparison between Curitiba's production and consumption of resources (food, construction materials, energy etc.) suggest that the city is not capable of producing everything it consumes, and does not have the adequate amount of space to dispose its waste. In order to maintain its sustainability, it uses (directly or indirectly) land spaces beyond its administrative limit, disassociating its ecological location from its geographical location (Steinberger, 2001; Rees and Wackernagel, 1996). This analysis reinforces the problem previously mentioned by Wolman (1965), about the difficulty in completely describing the urban metabolism of a city, due to intense, complex and geographically dispersed economic interactions. The levels of commerce and globalization impede the correct observation of the city's own metabolism, as the demands of natural space will be supplied by other regions, making the environmental impact less visible (Rees and Wackernagel, 1996). Accepting that cities are going farther to acquire the resources needed to survive should change the debate over urban sustainability, as they should be accountable for the transference of environmental costs to other spaces (geographical regions), time (future challenges) and people (next generations). Consequently, it does not seem adequate to try to evaluate if one single city is sustainable or not, but instead, to understand its contribution to sustainable development. This contribution would depend on the production methods, consumption patterns and disposal amounts, as well as the level of well-being and opportunities created. Wachsmuth (2012, p. 515) then argues that problems in the city are not necessarily problems of the city. And he raises the question: “why should we look for municipal solutions to the pathologies of urban metabolism when the environmental pressures are universally understood to be regional or indeed planetary?” The case of Curitiba, for instance, helps illustrate the potential and the necessity of regional solutions to urban sustainability. Nowadays, the
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main landfill is located in the metropolitan area (32 km far from downtown), provoking higher costs, obstacles in logistics and an environmental burden. In order to overcome this challenge, the city conceived in 2007, an integrated waste management program (collection, separation, recycling and discharge) with other 21 cities located in the metropolitan area, following the successful experience with public transportation. Curiously, despite strong social concern with correct waste disposal, the project has not been implemented yet, due mainly to the lack of an adequate space for the landfill, disputes over the types of treatments available, disagreement about cost sharing and deficiency in basic contracts and legal requirements. For Curitiba (and any other city that supposedly take sustainability seriously), the need for continuous development should be considered together with the consequent environmental impact, both well measured by the urban metabolism approach. This evaluation of the production and consumption of resources and the generation of waste should be a mainstream activity that would surely help urban planning, design and decision-making. In future studies, besides monitoring the metabolic flow, there should be an analysis of the distribution of materials and energy within the city, which may reveal inequalities in use in different areas. Despite the challenges to deal with the balance between development and preservation, cities must be always aware of their contribution to sustainability, in order to prevent ecological and environmental problems from advancing faster than their solutions. Acknowledgements The authors would like to thank Oli Negrelle, Erlete Teresa and Marcio Silveira for their support during the development of this research. They also thank the reviewers for their valuable comments. References ber, A.N., 2004. A sociedade urbano-industrial e o metabolismo urbano (Urab'Sa ban-industrial Society and Urban Metabolism). Coleç~ ao Princípios 71, 54e57. Alberti, M., Marzluff, J.M., Shulenberger, E., Bradley, G., Ryan, C., Zumbrunnen, C., 2003. Integrating humans into ecology: opportunities and challenges for studying urban ecosystems. Bioscience 53 (12), 1169e1179. Bolund, P., Hunhammar, S., 1999. Ecosystem services in urban areas. Ecol. Econ. 29 (2), 293e301. Brunner, P.H., 2007. Reshaping urban metabolism. J. Ind. Ecol. 11 (2), 11e13. Burgess, E.W., 1925. The growth of the city: an introduction to a research project. chapter II. In: Park, R.E., Burgess, E.W., McKenzie, R.D. (Eds.), The City. The University of Chicago Press, Chicago, pp. 47e62. Goodland, R., Daly, H., 1996. Environmental sustainability: universal and nonnegotiable. Ecol. Appl. 6 (4), 1002e1017. Holmes, T., Pincetl, S., 2012. Urban Metabolism Literature Review. UCLA. Institute of the Environment and Sustainability. Center for Sustainable Urban Systems, Los Angeles. http://www.environment.ucla.edu/media/files/Urban-MetabolismLiterature-Review2012-44-fea.pdf (accessed May 2014). Hoornweg, D., Campillo, G., Saldivar-Sali, A.N., Linders, D., Sugar, L., 2012. Mainstreaming urban metabolism: advances and challenges in city participation. In: Sixth Urban Research and Knowledge Symposium 2012 (accessed May 2014). www.dennislinders.com/portfolio/Hoornweg_et_al_URKS6_Urban_ Metabolism.pdf. IWM. Chartered Institution of Wastes Management Environmental Body, 2002. City Limits: a Resource Flow and Ecological Footprint Analysis of Greater London. Best Foot Forward Ltd.. http://www.citylimitslondon.com/downloads/Complete %20report.pdf Kennedy, C., Hoornweg, D., 2012. Mainstreaming urban metabolism. J. Ind. Ecol. 16 (6), 780e782. Kennedy, C., Ibrahim, N., Stewart, I., Facchini, A., Mele, R., 2014. An Urban Metabolism Survey Design for Megacities. Enel Foundation/University of Toronto (accessed May 2014). http://www.enel.com/en-GB/enel_foundation/library/ working_papers/2014/. Kennedy, C., Pincetl, S., Bunje, P., 2011. The study of urban metabolism and its applications to urban planning and design. Environ. Pollut. 159, 1965e1973. Kennedy, C.A., Cuddihy, J., Engel Yan, J., 2007. The changing metabolism of cities. J. Ind. Ecol. 11 (2), 43e59. Medeiros, E.B., 1975. O lazer no planejamento urbano (Leisure in Urban Planning). FGV, Rio de Janeiro.
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