Society-nature interactions in sustainable cities:
Helsinki as a case study
Eeva Huttunen a , Gerald Krebs b , Odenna Sagizbaeva a ,
Theresa Willerstorfer a
a
University of Helsinki, Finland
b
Aalto University, Finland
March 31, 2011
Abstract
The challenge to achieve sustainable urban development has been in political agendas since the
mid 1990’s and becomes increasingly important as urban areas already replaced rural areas as the
dominant human habitat. Population densification is associated with land cover change, high energy
and resource demands, and disposal of used goods, such as waste, water, and polluted air. Ecosystem
service areas needed for ecological resilience of cities exceed the geographical borders of cities by far,
creating a dependency between cities and their hinterlands. This dependency shows that sustainable
urban development does not only mean a city sustaining its own existence, but a city that contributes
to even global sustainability. This report analyzes and questions the necessary efforts and
developments toward urban sustainability, and their implementation in the City of Helsinki, Finland.
We focus on four major issues of urban sustainability: water management and land-use, energy
production and consumption, waste management, and transportation. We investigate common current
practices, sustainable approaches, and targets and their implementation in the City of Helsinki to
conclude with questions on the sustainable urban socio-ecological system.
1
1. Introduction
of
sustainable
cities
“The increasingly harmful impacts of cities on the natural environment are rooted in their origins.
Cities are artificial habitats created primarily for one species […]” (McKinney, 2010, p.289). This
quote gives us an insight into the city’s role as major driver of and responder to environmental change.
The topic of interest, the following report is dealing with, is the aim of a so called sustainable city.
Nowadays almost 50% of the global population - more than 3 billon people - is living in cities and this
proportion is going to rise within the twenty-first century (Grimm et al., 2008; McKinney, 2010)
(Figure 1).
Fig. 1. Urbanization rates during the last 100 years. (Arnulf Grubler, IIASA)
High population densities of cities accompany high resource demand and release of waste, which
exceed the ecological and geographical boundaries of a city by far. On the other hand there is the
potential of concentrating human impact to a certain amount of area – e.g. a high population density
leads to a lower per capita energy demand and environmental impact due to efficient use of physical
infrastructure such as transport (McKinney, 2010). “Generally, the efficiency savings of more compact
city development as compared with market driven suburbanization can be as high as 7 to 54% in land
resources, 5 to 20% in the construction of local roads and 5 to 8% savings in the provision of water
and sewage facilities” (MVV Consulting 2007, p.62). Thus a compact city is the exact opposite of a
sprawling city and contributes to a lower demand of energy and other resources such as land.
Trade-offs and interdependences between nature and society can be explained within the concept
of society-nature coevolution and metabolism.
1.1
Society­nature
coevolution
and
metabolism
Co-evolution offers a useful logic for studying interactions between ecological and social systems.
It is a tool to demonstrate, how everything is related to something else. Two systems coevolve, when
at least one of them is evolving through variation, inheritance and selection, and they have a causal
influence on each other’s evolution (Kallis and Norgaard, 2009). The relationship between the systems
can be co-operative, but also for example competitive or predatory, i.e. exclusive. Kallis and Norgaard
distinguish five types of coevolution: Biological, social, gene-culture, bio-social and socio-ecological
coevolution. Here we concentrate on socio-ecological coevolution.
2
Gual and Norgaard (2010) proposed a conceptual framework to support coevolutionary thinking
(Fig. 2). They suggested that it is useful to make a distinction between systems and processes when
looking at coevolution. They define three embedded systems: biophysical, biotic and cultural. These
systems evolve by processes that are interconnected in many ways. Coevolutionary theory focuses on
studying the basic units, characteristics and modes of these processes and on how these processes
relate to one another.
The process of cultural evolution affects both the biological processes of microevolution and
macroevolution. This can happen
(1)
(2)
(3)
through large-scale biophysical impacts (e.g. waste water emissions causing changes in
coastal species composition)
through consciously designed cultural products that act as selection forces in
coevolutionary events (e.g. pesticides-pests stories)
deliberately manipulating genetic information.
In socio-ecological coevolution a social system affects the bio-physical environment, which in turn
affects the evolution of social systems (Gual, Norgaard, 2010). Bio-physical system doesn’t evolve in
a Darwinian sense, but is manipulated by evolving social systems. For example, evolving water
technology changes the consumption patterns and ways in which water is used, which affects the water
resources and ecosystems, which in turn is a new challenge to water technology.
Fig. 2. Conceptualizing coevolution. (Gual and Norgaard, 2010)
A city can be seen as a socio-ecological system, where social and ecological processes interact.
There are also many systems of different level inside a city, such as technological systems, economic
systems and institutional systems. It is important to take into account, that a city is not an independent
system, but changes in systems at national and global scale also have an impact on society-nature
interactions in regional systems (Krausmann et al. 2011). It is difficult to study nature-society
coevolution in a city without historical data from longer period, therefore in this work we concentrate
mainly on interactions between nature and society.
One way of studying interactions in socio-ecological systems is to study the metabolism between
society and culture. Krausmann et al. (2008) used the concept of socio-metabolic regimes (originally
3
by Sieferle, 1997) to represent the dynamic equilibria of society-nature interactions. These interactions
are characterized by typical metabolic profiles. Krausmann and Fischer-Kowalski (2011) emphasized
the role of energy in social metabolism, because the amount and availability of energy place limits on
resource use and other forms of altering nature. Transitions from one socio-metabolic regime to
another have been studied empirically, such as the industrial revolution (transition from agrarian to
industrial regime), which is a still ongoing process (Krausmann, Fischer-Kowalski, 2001).
An ideal sustainable city might be seen as an example of a new socio-metabolic regime, where
material and energy flows are closed and sustainability taken into account in all processes.
1.2.
Sustainable
city
How can environmental goals towards a sustainable city be achieved in terms of adapted resource
and energy use? First of all it is necessary to ask what comes to our mind when we are talking about
sustainability. The term sustainability was defined in 1987 as “development that meets the needs of the
present without compromising the ability of future generations to meet their own needs” (Brundtland
Report, 1987). “A ´sustainable` city is thus not just a city that sustains its own existence. Rather it is a
city that contributes to the long-term persistence of the biosphere and indeed the global environment”
(McKinney, 2010, p.287). Hence a certain city can be seen as a microcosm of changes which occur
globally. 78% of carbon emissions, 60% of residential water use and 76% of industrial wood can be
attributed to cities although only 3% of the global terrestrial surface is urban area. This leads to land
cover change, altered biogeochemical cycles and hydro systems, biodiversity loss and climate change
(Grimm et al., 2008).
Major resource inputs into a city´s social metabolism are construction materials, water and energy.
There are huge disposals of waste and emissions which do not enter the metabolic cycle again.
Referring to that, the most important goal is to move beyond linear flows of material and energy
(McKinney, 2010).
There are two main ways of reducing the metabolism of a city mentioned in literature – the
increase of energy efficiency by technological inventions and progress, and the reduction of material
demand by means of reuse and recycling of goods (McKinney, 2010). A third possibility which has
almost never brought up is the reduction of resource and energy demands by less consumption of
goods or rather an alternative living standard.
Another issue which should be taken into account is the option to increase resource efficiency by
redesigning the city itself. “[...] rethinking the way that cities are designed, constructed and maintained
could significantly reduce the total and per capita anthropogenic impact on the natural environment, as
well as maintain a high quality of life for humans” (McKinney, 2010, p.292).
2. Sustainable
development
in
Helsinki
City as an organization has various impacts on the environment as it uses natural resources and
causes environmental degradation through its functions. City also creates operational preconditions for
growth-based production, which causes pressure to the environment locally and globally (City of
Helsinki, 2009). A city could be seen in different roles as a cause of environmental problems, definer
of problems, sufferer of the ecological, social and economic impacts and as a problem-solver.
In the end of 2010 Helsinki had 588 549 inhabitants (Tilastokeskus) and the Metropolitan area
including Espoo and Vantaa over 1 million. It is one of the fastest growing metropolitan areas in
Europe and the rapid growth causes pressure on social as well as ecological systems.
4
Sustainability has various definitions (e.g. Brundtland report 1987). In 1995 the Finnish National
Commission on Sustainable Development defined sustainable development as “a continuous, guided
process of societal change at global, national, regional and local levels aimed at providing every
opportunity to present and future generations to live a good life”. Biodiversity must be preserved and
economic and other activities adjusted to our global natural resources and nature's carrying capacity in
order to reach ecologically sustainable society (City of Helsinki, 2002).
Actions towards sustainability as we now understand it were taken in Helsinki before the concept
existed, for example improving water management systems has had a great effect on the state of
coastal ecosystems. Helsinki City Council began to discuss the sustainability issues in Helsinki in the
1990s, but they were first brought to political agenda in 1997, when the City Council decided to
launch the Local Agenda 21 process. Main goals of this sustainability plan were to reduce greenhouse
gases, protect biodiversity, increase citizen interaction and participation, and develop methods for
measuring and evaluating sustainable development and to implement suburban renewal according to
the principles of sustainable development. In 1997 sustainable development was specified for the first
time as one of the city's common strategies. In 2002 the City Council approved the Helsinki Action
Plan for Sustainability. The main goals of this plan were to adapt the city's long-term development to
the ecological boundary conditions set by the global environment (City of Helsinki, 2002).
City as a decision-making system is not independent, and it is influenced by larger-scale systems.
Changes in the environmental legislation in Finland and EU have had a positive effect on the decisionmaking process on city-scale from an environmental perspective (Kansanen, 2004). A new housing
area in Viikki is an example of this. A unique totality of nature conservation area and cultivated fields
was a challenge for the city planners, who were to build a new housing area. In the beginning of the
process in 1989 there was no legislation to follow to measure the environmental impacts of such a
project, but the planners took a voluntary experiment and did the very first environmental impact
report for this project. The recommendations of the report led, for example, to changing the proposed
built areas further away from the nature conservation area (City of Helsinki, 2005).
As a part of Agenda 21 indicators used to measure sustainable development in Helsinki were
developed. These indicators are divided into five themes:
−
−
−
−
−
global-scale sustainability perspective (e.g. ecological footprint, GHG emissions),
local state of and pressure on the environment (e.g. water and energy consumption per capita)
socioeconomic factors (e.g. health, level of education)
comfortability and service level of immediate surroundings (e.g. safety)
participate and responsible action (e.g. environmental attitudes, voting activity). (City of
Helsinki, 2006)
In this work we concentrate on the first two of these themes, as they represent the metabolism
between social and ecological systems. The city of Helsinki serves us as case example for our
examination with this topic since there has been great effort to include environmental management as
part of the city government (City of Helsinki, 2008). We focus on four major issues relating to
sustainable cities: land use and water management, energy production, waste management and
transportation.
2.1
Water
management
and
land­use
Urbanization is commonly associated with construction of building facilities and infrastructure to
inhabit growing population with increased structure density. These changes in land-use lead to higher
levels of impervious cover within urban developments and reduce the availability of ecosystem
services provided by green areas within the city borders. These services reach from air filtering, noise
5
reduction, and recreational values to stormwater drainage and sewage treatment (Bolund and
Hunhammar, 1999) and are directly related to human health (Tzoulas et al., 2007). Areas providing
ecosystem services can be natural areas such as forests and water bodies, but also manmade areas such
as lawns, parks, playgrounds and even golf courses (Bolund and Hunhammar, 1999). Increasing
densification of urban areas is beneficial concerning public traffic availability or energy efficiency, but
increases the dependency of urban agglomerations on their hinterlands to provide required resources
and to receive city emissions (such as air, water, and waste). For the Baltic Sea region required
ecosystem support areas were estimated 500-1000 times larger than the actual city areas (Folke et al,
1997) (Fig. 3).
Fig. 3. Location of the 29 largest cities in the Baltic Sea drainage basin and their ecosystem area demand.
(Folke et al., 1997)
Water is among the most essential sources needed for human life. Thus sustainable clean water
supply, stormwater management, and wastewater treatment have become a major challenge for urban
planning and management (Biswas, 2006). Whereas the supply of clean water for urban areas in
developed countries works mostly satisfactory, the disposal of used water (both wastewater and
stormwater), even after treatment, to the environment is seen increasingly unsustainable (Daigger,
2009). Two traditional ways are in use for water disposal in urban areas: 1) separate wastewater and
stormwater sewer network, where wastewater is directed to wastewater treatment plants (WTP) and
stormwater discharged untreated to water bodies and 2) combined sewer networks, where both
wastewater and stormwater are processed in treatment plants before discharged to the environment.
Even though these systems have been working in some areas for the last century already, the change
toward a more sustainable approach is needed for two reasons: 1) Maintenance of current sewer
networks is expensive and requires resources, especially when considering the age of most of the
urban networks (Smith, 2009) and 2) direct discharge causes hydraulic stress to water bodies and
contains pollutant loads, even after the water has been treated (Lee and Heaney, 2003; Beighley et al.,
2009). Furthermore, the combined water sewer network is usually designed to discharge water
exceeding the WTP capacity during a storm event, directly to the environment. This excess water
transport, despite being diluted, still pollutants found in domestic wastewater (Smith, 2009). The
stormwater collected through separate sewer networks, transports pollutants from contaminated
surfaces (such as roads, parking lots, and roofs) and discharges to the environment without adequate
infiltration (Bannerman et al., 1993; Ruth, 2003).
6
Besides quality and quantity impacts on surface waters, water cycle changes caused by
urbanization also affect the groundwater recharge and quality (Haase, 2009; Arnold and Gibbons,
1996), hence affecting also supply of drinking water in many areas. Furthermore local flooding,
caused by storm events, implies risk to property and human health.
2.1.1
Sustainable
water
management
and
land­use
A suitable approach to achieve sustainable urban water management has to modify both, current
land-use planning principles and water collection and treatment processes. Today’s used “end-of-thepipe” solutions concerning water collection and treatment in centralized facilities is proving
increasingly unsustainable (Daigger, 2009). Decentralized water treatment options, referred to as low
impact development (LID) or best management practices (BMP) are understood to be insufficient to
fully replace water networks in urban areas (Smith, 2009), but they can play an important role to
increase treatment capacity, decrease pollutant loads and reduce hydraulic stress, especially in respect
to stormwater. BMP and LID practices aim to reduce the quantity of surface runoff (for example by
using pervious surface materials) and utilize pollutant removal techniques as close to the event scene
as possible.
Techniques for water treatment have been copied from nature, such as infiltration, or retention and
detention in wetlands. For the Kylmäoja watershed in Vantaa, Finland, a surface runoff reduction
potential of up to 8% was found if 20% of current asphalt surfaces were replaced by pervious
materials (Krebs, 2009). An important aspect of LID is the building layout. A residential area designed
in a way to minimize connection roads (for example with one common parking lot instead of lots in
front of every door) reduces the creation of surface runoff potential (Schueler, 1994). The conceptual
design of wetlands and ponds for local water treatment has been well documented (Schueler and Galli,
1992; Smith 2009). As the surface material is the main parameter to influence surface runoff, the
reduction by using green roofing has also been studied (Mentens et al., 2006). Reduction of the second
main parameter besides the surface material, the size of the surface was studied in Vantaa (Krebs,
2009). The increase in building height – for the same given net floor area – resulted in a reduction of
roof surface. The reduction in surface runoff was modeled to reach 16% for high rise building areas
(Krebs, 2009). The reuse of rainwater and greywater has been widely discussed for irrigation
purposes. This would reduce the water loads reaching WTP’s and nutrients would be reused for
cultivation, reducing eutrophication in water bodies.
2.1.2
Water
management
and
land­use
in
Helsinki
Water supply in Helsinki is currently operated with two water treatment plants in Pitkäkoski and
Vanhakaupunki. In these plants raw water taken from Lake Päijänne, transported through a 120
kilometer long rock tunnel is purified to obtain clear domestic water. The overall water supply
network length in the Metropolitan area (Helsinki, Espoo and Vantaa) is about 2900 kilometers, of
which 300 kilometers are water mains. HSY Water, responsible for water services in the Helsinki
Metropolitan areas, takes about 86 million cubic meters of water per year from Lake Päijänne.
Treatment plant processes include the removal of humus, ozone and carbon dioxide treatment, and
activated carbon filtration. Average water consumption in Helsinki is 158 liters per day. The
introduction of a wastewater charge in the 1970’s helped to decrease the per capita consumption by
35% between 1975 and 2008. (Helsingin seudun ympäristö palvelut, 2011)
Water in the Helsinki metropolitan area is collected using a separate sewer system for wastewater
and stormwater mostly, except the Helsinki city center, which is served by a combined sewer system.
HSY Water operates two wastewater treatment plants today in Viikinmäki, Helsinki and Suomenoja,
Espoo, treating a total of 100 million cubic meters per year. The per capita generation of wastewater is
7
about 160 liters per day. The sewer network of the Helsinki metropolitan area spans over 2000
kilometers. Even though it was designed to operate by gravity alone, 500 wastewater pumping stations
are needed mainly due to city expansion to lower areas. Due to deterioration, HSY Water plans to
renovate all water and sewer pipes in the region built before 1970 by 2030. (Helsingin seudun
ympäristö palvelut, 2011)
2.1.3
Efforts
taken
toward
sustainable
water
management
in
Helsinki
The city of Helsinki covers a total area of 715 square kilometers, of which the sea accounts for the
biggest ecosystem support area with 503 square kilometers (City of Helsinki, 2010). Green areas
account for 40% of the land area and in 2004, 98% of Helsinki residents lived less than 300 meters
from a green area and 100% less than 700 meters (City of Helsinki, 2008). The goals set in the
Helsinki Action Plan for Sustainability (2002) for land-use promote the reduction of greenhouse gas
emissions and safeguard biodiversity with the emphasis on compaction, densification, and infill of
areas of land-use change, as former industrial areas and port facilities. Concerning water supply and
wastewater treatment is mainly based on technical measures. Protection of the Baltic Sea through
nitrogen and phosphorus removal thresholds, discharge reduction of hazardous substances to the
environment and improvement in snow clearance and handling practices are promoted (City of
Helsinki, 2002). Efforts made for Baltic Sea protection can be nowadays seen as improvement in
water quality (Fig. 4). Furthermore the City Board approved a stormwater management strategy in
2007 (target year 2013) to decrease dispersed discharges and non-point source pollution to the Baltic
Sea through the stormwater drainage system (City of Helsinki, 2010).
Fig. 4. Water quality of the Baltic Sea off Helsinki and Espoo 1974-1976 (left) and 2004-2006 (right). The ends of the
treated wastewater discharge pipes are marked with an arrow. (City of Helsinki, 2008)
In the mid 1990’s plans for an eco-village in Viikki, Helsinki (ECO-Viikki) were initiated and
implemented with the focus on urban sustainability. Ambitious goals were set for the pollution, use of
natural resources, health, biodiversity, and nutrition for both, construction and living. To achieve these
goals, special building designs, street layouts, and were implemented. Concerning water, the goal was
set to a water consumption of 125 liters per person per day at the minimum and 85 liters per day. Same
parameters were defined for waste generation, energy consumption, and air emissions. The design of
the village includes a surface water runoff network and water reuse for irrigation. Common saunas for
apartment blocks aimed to minimize water use and maximize social integration at the same time. First
results were presented in 2005. The water consumption measured over the test period was 126 liters
per person per day, slightly higher than the minimum goal set of 125 liters, but 22% less than the
Helsinki average consumption. One reason issued was the high share of families with small children in
8
the area, thus the water consumption is expected to decrease with time. Surveys in the village also
showed, that even though for the majority of residents the main driving force to move to ECO-Viikki
was not sustainability in first place, residents got more aware of environmental issues during the time
living there (City of Helsinki, 2005).
2.2
Energy
production
2.2.1.
Energy
production
in
Helsinki
Comparing to many other European capitals, the challenge of energy production in Helsinki is the
cold climate, which increases energy consumption and emissions greatly during winter months.
Helsingin Energia is one of the largest energy companies in Finland and produces electricity and
heat for over 400 000 people. It supplies 90 percent of the heating demand in Helsinki with district
heating and produces district cooling in Helsinki area as well (Helsingin Energia). Helsingin Energia
causes 4/5 of all greenhouse gas emissions in Helsinki (City of Helsinki, 2010). Helsingin Energia has
five power plants in Helsinki that are based on co-production of electricity and heat and nine power
plants producing distric heating. Co-production is cost-efficient and produces less CO2 than separate
power plants, but is, however, based on fossil fuels. Only a small part of the electricity supplied by
Helsingin energia is produced by renewable energy sources as the major energy sources are gas and
coal (Helen annual report 2009).
1.2.2. Towards
sustainable
energy
production
In the Action Plan for Sustainability (City of Helsinki, 2002) energy is one of the key issues. The
main goals for increasing sustainability in energy production are developing co-production of heat and
electricity (which already is on a very high level) and reducing fossil-fuel dependence in Helsinki
region by increasing use of renewable energy sources. The plan is to do this in such a way that it
remains possible to use coal in the co-generation plants until the end of their functional technical or
economic life. These two goals can be seen as contradictory in a way, unless the increase of renewable
energy sources means decrease in the share of nuclear energy. The Action Plan also emphasizes the
role of investigating possibilities for new technology, such as solar, wind, biofuels and waste-derived
fuels. Also emissions of sulphur dioxide, nitrogen oxide and particles should be kept under the
emission limits. (Action Plan for Sustainability 2002.)
Aim in the Action Plan was to reduce the total emissions of greenhouse gases generated in the City
of Helsinki to the 1990 level by 2010. This includes all emissions from different sectors, but energy
production is in the biggest role with its over 4/5 share of total greenhouse gas emissions. This target
was reached easily and in the year 2009 emissions were already 13 percent lower than in 1990. A
slowly declining trend in emissions accelerated in the end of the period mostly because of the
economic crisis. (City of Helsinki, 2009).
In 2008 City Council approved new, a bit more strict energy policy guidelines that follow the
goals of European Union that were presented the same year. Greenhouse gas emissions must be
reduced with 20 per cent and the share of renewable energy sources in energy production must be
increased up to 20 per cent by year 2020 (City of Helsinki 2010).
A more ambitious goal is the carbon neutral production by 2050, a target which Helsingin Energia
and other major European energy companies have set. To reach this goal the use of forest-based
biofuels and wind power must be increased. Helsingin Energia is planning to build wind power
9
offshore. According to the plan nuclear power is also needed to reach the goal of carbon-free energy
production (Helsingin Energia 2010).
2.3
Waste
management
Waste management includes collecting, transportation, processing, recycling or disposal, and
monitoring of waste materials produced by human activity, the aim of the process is reducing of waste
effect on health, the environment or aesthetics. Waste management is also carried out to recover
resources from it (Wikipedia.org).
Modern systems of waste management include municipal waste (includes household waste,
commercial waste, demolition waste), hazardous waste, biomedical waste and explosives waste.
Waste attracts rodents and insects which cause health risk for humans. Exposure to hazardous
wastes, particularly when they are burned, can cause various other diseases including cancers. Waste
can contaminate surface water, groundwater, soil, and air which cause more problems for humans,
other species, and ecosystems. Waste treatment and disposal produces significant green house gas
emissions (notably methane) are contributing to global climate change according to U.S.
Environmental Protection Agency.
The economic costs of managing waste are high, and are often paid for by municipal governments.
Waste recovery can curve economic costs because it avoids extracting raw materials (Wikipedia.org).
2.3.1
Methods
of
disposal
Waste management system includes landfill, incineration, recycling and biological processing.
Landfill is traditional management method. Disposing of waste in a landfill is a common practice
that involves burying the waste. A properly designed and well-managed landfill can be a hygienic and
relatively inexpensive method of disposing of waste materials. The poorly managed landfills can
create a number of adverse environmental impacts such as wind-blown litter, attraction of vermin, and
generation of liquid leachate. Another common byproduct of landfills is gas (mostly composed of
methane and carbon dioxide), which is produced as organic waste can create odour problems, kill
surface vegetation, and is a greenhouse gas. (Wikipedia.org)
Incineration is a practical method of disposing of certain hazardous waste materials (such as
biological medical waste). This method is useful for disposal of residue of both solid waste
management and solid residue from waste water management. Incineration is a form of thermal waste
treatment, and it can be considered to have four objectives: reduction of the waste volume,
stabilization of the waste, recovery of energy from waste and sterilization of waste. But it is a
controversial method of waste disposal, due to issues such as emission of gaseous pollutants. In Life
cycle assessment report (Dahlbo et al., 2005) incineration is divided into the stages: incineration
process, energy recovery, emission control, and treatment of solid residues.
Recycling is processing of used material into new products to prevent waste of potentially useful
materials. Recyclable materials include many kinds of glass, paper, metal, plastic, textiles, and
electronics. Although similar in effect, the composting or other reuse of biodegradable waste – such as
food or garden waste – is not typically considered recycling. Undoubtedly, benefit from the recycling
is great: decrease of air pollution and greenhouse gases from incineration, reduce of hazardous waste
leaching from landfills, reduce of energy consumption, and reduce of waste and resource consumption,
which leads to a reduction in environmentally damaging mining and timber activity (Table 1).
10
Table 1. Environmental effects of recycling (Wikipedia.org)
Material
Energy savings
Aluminum
95%
Air pollution
savings
95%
Cardboard
24%
-
Glass
5-30%
20%
Paper
40%
73%
Plastics
70%
-
Steel
60%
-
Biological reprocessing includes recycling of the organic materials using biological composting
and digestion processes to decompose the organic matter. The resulting organic material is then
recycled as mulch or compost for agricultural or landscaping purposes. In addition, waste gas from the
process (such as methane) can be captured and used for generating electricity and heat maximizing
efficiencies. The intention of biological processing in waste management is to control and accelerate
the natural process of decomposition of organic matter.
Energy recovery means the use of the waste as a direct combustion fuel, or indirectly by
processing them into another type of fuel. Recycling through the thermal treatment ranges from using
waste as a fuel source for cooking or heating to anaerobic digestion, and the use of the gas fuel to fuel
for boilers to generate steam and electricity.
2.3.2
Sustainability
and
life
cycle
assessment
Sustainable waste management, however, will not resolve of continuous production of waste.
While the production and consumption of goods increases, waste amounts will also grow. The
durability and long life of products and consumption of non-material experiences reduce the waste
amounts. The more effective use of natural resources reduces waste amounts related to production.
Waste minimization or prevention has been set as the first priority of waste management in the
waste policy of the European Union. Prevention is hierarchically followed by material recycling,
recovery as energy and, as the last option, safe final disposal.
According to Dahlbo et al. 2003, increased recycling and energy recovery of waste materials have
raised the profile of waste management as one of the critical sectors contributing to sustainable
management of natural resources. The environmental dimension of sustainability in waste
management addresses on one hand pollution and on the other hand resource conservation. Concerns
over conservation of resources have led to calls for a) general reductions in the amount of waste
generated, i.e. waste minimization or waste prevention, and b) ways to recover the material and/or
energy in the waste, so that they can be used again. Recovery of resources from waste should slow
down the depletion of non-renewable resources, and help to lower the use of renewable resources to
the rate of their replenishment.
Life cycle assessment (LCA) is an environmental management tool that aims to predict the overall
environmental interventions of a product, service or function. Integrated waste management using
LCA attempts to offer the most benign options for waste management. The main aim of integrated
waste management is to develop more sustainable waste management systems. It is an approach that
11
emphasizes the environmental effectiveness, economic sustainability and social aspects of a waste
management system.
As the example of the approach, the joint project of Finnish environment institute (SYKE) and the
University of Helsinki called “Life cycle approach to sustainability of waste management – A case
study on newspaper” can be considered (Dahlbo et al., 2005). The modeled area was the Helsinki
Metropolitan area (MHA) as the most densely populated area in Finland (the area is 0.2% of the whole
country, but ~20% of Finland's population lives there). The paper waste was studied because it is one
of the largest fractions of municipal solid waste. The current waste management system is based on
separation at source. The project paper describes the current situation in HMA (Fig. 5).
Fig. 5. Newspaper waste management in HMA. (Dahlbo et al., 2005)
Discarded newspapers are collected either separately or with mixed waste. The separately
collected newspapers are recycled as material for the manufacturing of newsprint and the mixed waste
is landfilled. The separately collected newspapers are first transported to the processing plant of
Paperinkeräys Oy, where they are loaded into lorries either baled or loose, and then transported further
to the Kaipola mill for newsprint manufacturing. Newspaper in the mixed waste is collected and
transported to the Ämmässuo landfill maintained by the YTV Waste Management. Newspaper in the
mixed waste is in the present situation landfilled in the only operational landfill in the HMA, the
Ämmässuo landfill. This landfill for non-hazardous waste became operational in 1987. The anaerobic
degradation of organic material produces landfill gas which is collected with drainage and suction well
systems. In 2002, 75% of the landfill gas was collected and flared off without energy recovery at the
Ämmässuo landfill. Energy recovery of the landfill gas was started, however, in the end of 2004. The
gas is currently used for producing heat for district heating.
2.3.3
Waste
management
as
part
of
Helsinki’s
sustainability
strategy
Waste management in Helsinki Metropolitan Area (HMA) is considered in the present report.
From the Environment Centre of Helsinki report (City of Helsinki, 2010) residents are notified that
Helsinki Region Environmental Services Authority (HSY) is responsible for arranging the waste
management and transport for residential buildings and the properties of the public administration
throughout the metropolitan area. There are several recyclable wastes that are collected. These include
organic waste, paper, carton, cardboard, metal, glass, wood and hazardous wastes.
12
Waste prevention. According to waste prevention strategy (City of Helsinki, 2002), the top
priority in the waste management sector is waste prevention and reducing of the amount of waste and
hazardous waste for final placement at refuse tips. In accordance with the national waste plan, the aim
is to increase the degree of utilization of household and building waste. Other major goals are to make
sorting and sending for utilization cheaper than for mixed waste and to reduce the impact of waste and
waste management on health and the environment through more effective transportation and
supervision (City of Helsinki, 2002). Compost made from organic waste is used in landscaping.
Biogas is also collected from old landfills and waste treatment plants.
In 2006 the Helsinki Metropolitan Area Council (YTV) changed the waste management strategy in
the region. It resolved that source-separated mixed waste should in future be used to produce energy.
A new incineration plant is being planned (City of Helsinki, 2007). The average inhabitant in Helsinki
produces annually 300kg of household waste, and about 55% of it recycled or reused informs (City of
Helsinki, 2010). HSY states that domestic recycling has generally become more popular, that over
90% of the residents state that they recycle paper, nearly 80% recycle cardboard and approximately
70% recycle glass waste on a regular basis (City of Helsinki, 2010).
Currently in Finland producers are also responsible for the organization of the waste management
for their products. The principle already applies to waste from electrical and electronic appliances,
used tyres, paper products, end-of-life vehicles, batteries, and to some extent packages and packaging
waste (City of Helsinki, 2010).
Waste-Fired Power Plant Project. HSY is granted the environmental permit to build the gas
power plant, which will use biogas collected from the Ämmässuo landfill (HSY). Reducing
greenhouse gas emissions is still a major challenge for Helsinki, This challenge is being taken into
consideration in many development plans and programs under preparation in Helsinki and the
metropolitan area. HSY promises to increase the efficiency of organic waste management by
constructing a biogas digester to extract biogas from the collected organic waste before the
composting process.
Vantaa Energy Ltd will erect a waste-power plant in Vantaa (Vantaa Långmossebergen) during
2011-2014. The output of the plant is electricity and heat will be used for municipal district heating.
The prognoses from the plants about ashes, slag, and airborne emissions look very optimistic. A plant
incinerating some 320 000 tons of waste, generates ~70.000 tons of incineration residue per year. A
portion of the incineration residue is recyclable. After treatment, the remainder will be forwarded to
HSY’s waste treatment centre in Ämmässuo. Flue gases are efficiently purified by the best available
technology (BAT). The purity of the flue gases released from the plant meet the requirements defined
in the decree on waste incineration. The emissions are insignificant compared to those of a coal-fired
or peat-fired power plant, for example (HSY).
2.4.
Transportation
One major challenge for cities to become more sustainable is the shift to and improvement of
public transport. In 2006 there were approximately 491 million inhabitants in the European Union (EU
27). The covered distance was 34 km per capita per day - 26 km of which by passenger car. The
number of cars in the EU-27 grew from 1990 to 2006, at an average yearly rate of 2.4% and the
number of busses and coaches 0.7% yearly on average (Eurostat, 2009, p.39). The final energy
consumption was with a share of 26% highest in Road transport and therefore contributed to 93% of
greenhouse gas emissions in the transport sector – excluding air and maritime transport, as well as
electrical traction for Rail. 40% of these emissions are due to Urban Transport (Eurostat, 2009; MVV
Consulting, 2007). In 2005 56% of the total energy consumption in Road transport was covered by
13
private cars. Over the period 1995 to 2006 the annual growth rate of final energy consumption in Road
transport was 1.8%. Despite an average decrease in greenhouse gas emissions of 0.5% from 1990 to
2006, transport was the only sector without reductions in the EU-27 – quite the contrary an annual
growth rate of 1.5% was recorded (Eurostat, 2009).
2.4.1.
The
transport
system
of
Helsinki
Setting the boundaries of a city as the administrative unit of a certain area, issues taken into
account are only referring to transport taking place within this area. Thus we are looking at the
transport system of Helsinki city but not at the transport habitats of each inhabitant when it exceeds
the boundaries of the city.
Helsinki has pursued a policy of favoring public transport since the 1970s and transport system
plans with a four year planning cycle have been created by the Helsinki Region Environmental
Services Authority since the 1990s (City of Helsinki, 2010). The length of public transport system as
well as the bicycle network per capita is above the average of the European Union due to a low
population density (Eurostat, 2009; Urban Audit, 2004).
In general 30% of all trips in Helsinki region are made by car, 32% by public transportation, 29%
on foot and 7% by bicycle (City of Helsinki, 2010, p.19). 62% of the commuters used public transport
to the city centre of Helsinki during the years 2004-2006 (City of Helsinki, 2007). Compared to cities
like Copenhagen or Amsterdam where 46 to 60% of the residents go to work or training place by bike,
the amount of cyclists is with approximately 10% in Helsinki rather low (European Commission,
2010).
Fig. 6. Modes of transport in the daily travel in the Helsinki region, 2008. (HSY Litu 2008)
As we can see in Figure 6 the proportion of people using private cars is higher in the suburbs than
in the city centre, presumably due to a low public transportation. Urban sprawl can be understood as
the expansion of non-densely populated urban areas across large areas and accompanies increased
transport related energy consumption and therefore higher CO² emissions. It has not only negative
effects on the environment but also on the economy and society in general (MVV Consulting 2007).
2.4.2.
Helsinki
Region
Public
Transport
System
Plan
HLJ
2011
HLJ is a comprehensive planning system that takes not only traffic patterns but also land use and
urban structure into account. It covers 14 different municipalities and the total population covered is
1.3 million over an area of 3751 km². The impacts of the plan are monitored and assessed by the Act
on the Assessment of the Impacts of the Authorities' Plans, Programs and Policies on the Environment
(SEA Act).
14
The main goal of HLJ is to achieve a high quality, eco-efficient public transport system which
promotes development and well being in the region of Helsinki. Considered impacts are those on the
environment, on land use, as well as on the functionality and safety of the public transport system
(HLJ, 2011) (Fig. 7).
Fig. 7. Strategy Framework of HLJ, based on the previous transport system plan PLJ 2007. (HLJ 2011)
2.4.3.
Satisfaction
with
Public
Transport
Systems
across
Europe
According to a survey of the Austrian automobile and motorcycle club ÖAMTC in collaboration
with 15 other European motoring clubs, Helsinki is second regarding to the satisfaction of the
residents with the public transport services. If we compare the results with the rates from the Survey
on perception of quality of life of the European Commission there are slight differences. According to
the European Commission Helsinki is first among 75 European cities with a rate of 42% of people
who are very satisfied with the public transport system (ÖAMTC, 2010; European Commission,
2010). But it should be considered that the ÖAMTC survey was carried out by motoring clubs and
therefore it is probably not as objective as the other one.
A high satisfaction with the public transport services is - at least theoretically - a driving force for
the frequent use of public transport. Hence it should correlate with the percentage of the population
using public transport as the main mean of transportation, and according to the Survey on perception
of quality of life the amount of people who use public transport every day is with 43% rather high in
Helsinki. Furthermore 30% of the respondents took a mean of public transport at least once a week
and only 3% said that they never used public transport. Helsinki is sixth among 75 cities (European
Commission 2010).
2.4.4.
Efforts
towards
a
Sustainable
Transport
System
in
Helsinki
city
The references we have been working with in this report are not suitable for making
generalizations about the quality of Helsinki’s transport system, but they give us an overview of the
efforts which have been taken in the last years to reduce energy consumption and emissions caused by
transport.
According to the report of the City of Helsinki, 2010, large scale projects such as the extension of
the metro-line to the city of Espoo, the construction of a railway connection to the airport and the
increase of cyclists to 15% by 2020 are at the planning stage. Referring to the use of clean energy
technologies the bus transport of Helsinki has started using sulphur free diesel fuel in 1994 and natural
gas driven busses in 1998 (City of Helsinki, 2007). According to a survey of the International
15
Association of Public Transport almost 20% of the buses in Helsinki are running on compressed
natural gas. But it should be taken into account that CNG is still a fossil fuel used as a substitute for
petrol, diesel and propane. Its combustion releases greenhouse gases although it is causing less impact
on the environment (Wikipedia, 2010). In addition, the use of public transport is much more efficient
than using a private car in general. Compared to other capital cities the number of registered cars per
1000 inhabitants is with 355 below the European average of 393. With ~28 km/km² Helsinki has the
third longest public transport network of 18 European cities (Urban Audit, 2004). In the long run a
goal for Helsinki´s public transport system is the use of renewable synthetic diesel fuels which are
produced from non-edible materials to close the entire life cycle of the fuel (City of Helsinki, 2008).
HLJ has tested and planned to use palm oil based biofuel produced by NESTE oil for public transport.
Political critics concerning major environmental and ethical questions from palm oil production have
led to a controversial debate if this can be seen as a sustainable solution for public transport. There is
pressure from political and non -governmental organizations to change the biodiesel production to
domestic based raw-materials (e.g. YLE uutiset 08.03.2011).
As mentioned in the beginning urban sprawl is also an important reason for high energy
consumption levels of transport. In our opinion the efficiency of public transport could be increased by
preventing further urban sprawl. For this attempt the collaboration with urban planners and designers
is needed.
3. Concluding
remarks
and
questions
Society-nature interaction in urban developments occurs in different levels. The way humans use
resources changes their availability, which again changes consumption patterns and poses challenges
on both, technological and political levels. After decades of strong technological development, to a
great share opposing natural processes, society started to copy nature behavior as a way to achieve
sustainability. This practice can be seen i.e. in urban stormwater management approaches, where the
trend clearly leads toward natural systems replacing or compensating engineering structures. Whereas
water management can use examples from nature for disposal, natural processes to dispose artificially
produced waste or to provide sufficient energy are not available. Concerning energy and waste, the
way to achieve sustainability is reduction of energy consumption and prevention of waste production.
In Helsinki, decreasing the use of coal and gas in energy production is an important step towards more
sustainable city. Finally, we end up with three questions:
1. Environmental issues and changes needed in practices and processes (waste, water, or air
management) toward ecological sustainability are not considered necessary and urgent by the
population, before actual effects can be seen (pollution, availability and prices of resources, damages,
and changes in life quality), which is late and sometimes too late. Science often knows problems and
works on solutions earlier, but is unable to promote results well enough to reach people’s minds. This
is an interesting issue to think about and forces us to ask what could be done to improve the social
acceptance for environmental issues and create awareness at an earlier stage.
2. Urban sustainability does not only mean a city sustaining its own existence, but a city
contributing to long-term persistence of the biosphere. In what spatial and temporal scale a city system
can be called sustainable? And can efforts taken within the city borders be called sustainable, if other
regions in national or even global scale are affected in an unsustainable manner (example of palm oil
bio-fuel used for Helsinki public traffic busses)?
3. Credibility of promises and forecasts, and uncertainty involved in research is used as an
argument against changes (sources for climate change, disease-pollution relations, and noise16
depression relation). How could people be convinced that changes concerning environmental issues
are needed even though their influences and causes cannot be 100-percent proven scientifically?
17
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