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Finnish City’s Environmental Success Wasn’t Built in a Day

Lahti, a small city of 120,000 in the south of Finland, is basking in newfound global fame as the 2021 recipient of the European Green Capital award, an honor extended each year to the most environmentally progressive metropolises in Europe.

Lahti from atop the ski slopes of its sports center ©Kallerna/Wikimedia Commons
Lahti from atop the ski slopes of its sports center. ©Kallerna/Wikimedia Commons

Lahti Wasn’t Always So “Green”

Lahti is among the oldest habited sites in Finland. Its name (in English, simply meaning “bay”) reflects its geographical location on the southern shore of a bay on Lake Vesijärvi in the Päijänne Tavastia region, where Lahti is the capital.

Lahti was first mentioned in documents in the 15th century. Industrialization of the city began from 1870 following the completion of the Riihimäk, Finland, to St. Petersburg, Russia, railway line.

Sometimes called the “Chicago of Finland,” Lahti was once known for its slaughterhouses and high crime rates. The city’s first municipal slaughterhouse was established in 1914 and private meat processing plants soon followed, the most well-known being the Liha Heinonen slaughterhouse. Substantial pollution issues commonly surrounded slaughterhouses at the time, and those of Lahti were no exception.

Lahti also had a considerable timber trade at one time, leading to its other moniker, “City of Carpenters.” In addition, Lahti also had glassworks, breweries, and clothing and machine-tooling factories.

First Steps in a Sustainable Direction

The city of Lahti began to take its initial steps toward becoming a green city in 1987 with the Lake Vesijärvi Project.

In the 1970s, Lake Vesijärvi (pronounced “veh-she-yahr-vee”) was one of the most polluted lakes in the country as a result of industrial waste and sewage runoff being directly discharged into the lake. This practice ended when a wastewater treatment plant was built in 1976.

The plant improved Lahti’s water quality, but a new problem arose soon after with the appearance of cyanobacteria—toxic blue-green algal blooms—in the lake fueled by an excess of nutrients through a process called eutrophication. To counter this problem, city authorities introduced a treatment pioneered by Finnish biologist Ilkka Sammalkorpi called biomanipulation, or the introduction of new forms of life to clean up pollution.

Lake Vesijarvi at night ©StAn/Wikimedia Commons
Lake Vesijarvi at night. ©StAn/Wikimedia Commons

The bioremediation project commenced in the early 1980s. Limnologist (a scientist who studies inland bodies of water) Juha Keto discovered that eighty-five percent of the fish in the lake consisted of roach. Roach are often the last species of fish to disappear when a body of water is polluted because they are bottom feeders whose food sources lie beneath the organic materials that remain unsettled and suspended in the water. To correct this imbalance, over a million kilograms (over a thousand tons) of roach were replaced by over a million individual pike perch. This strategy was effective in reducing the algal blooms, and the water began to clear.

By the 1990s, the condition of the lake had improved to such an extent that fishermen began to return. Unfortunately, other people took note and built houses close to the shore. Around the turn of the millennium, the harmful algae pollution had returned. The response this time was to initiate a second conservation project in which local people were taught about the lake and how to protect it. Many were eager to help, and today the health of the lake is constantly maintained through processes such as water aeration and selective fishing.

The Growth of Environmental Awareness in Lahti

The Lake Vesijärvi Project inspired the University of Helsinki to establish its Department of Environmental Ecology in Lahti. The university began to study and generate information on topics such as stormwater management, algae, green roofs, soil health, and the circular economy. The result of this initiative can be seen in new developments that manage stormwater via urban wetlands, infiltration basins, and green roofs. The city established a targeted stormwater project in 2011 that has continued research and efforts in this particular area, including the 2018 establishment of a project called Stormwater Smart & Clean.

Sustainable Energy and Climate Action Plan

Lahti’s Sustainable Energy and Climate Action Plan (SECA) was developed as part of an initiative called the 2030 EU Covenant of Mayors for Climate & Energy. It is currently in implementation and contains over ninety measures for adapting to climate change, including managing stormwater, decarbonizing traffic, and increasing citizen awareness. It sets a target of eighty percent reduction in emissions (compared to 1990 levels) by 2025 and a requirement for monitoring progress every other year, carried out by the city itself, with a new emissions calculation every four years. Areas identified for adaptation measures include infrastructure and land use, health and well-being, residential spaces, parks and green areas, the economy, and inter-sector impacts.

Lahti is located on what has always been an important trade route, connecting Finland’s capital city, Helsinki, to the Russian city of St. Petersburg. The city is also known as a cultural hub and a center of winter sports, particularly skiing. For all these reasons, an efficient transport system is essential for Lahti, but with climate change occurring, the city required that its transport services be sustainable and resilient, too. Lahti’s SECA has set a target for local transport to run off electricity and biogas by 2030. There is also a system of personal carbon trading in place with regard to transport. It is based on an app which directs people to the most sustainable ways of getting around.

Lahti lies on a key trade route, connecting Helsinki to St. Petersburg ©Ojp/Wikimedia Commons
Lahti lies on a key trade route, connecting Helsinki, Finland, to St. Petersburg, Russia. ©Ojp/Wikimedia Commons

Making housing more energy efficient is another priority for Lahti, including increasing the energy efficiency of the rented housing stock and repairing or replacing older buildings.

The city is also discussing a circular economy strategy, including the development of new sharing services and is contemplating how to increase citizen awareness of sustainability and climate issues through environmental counseling, both of citizens directly and through housing associations.

Lahti’s City Strategy 2030

Lahti has established a “City Strategy” to achieve key environmental targets that promote sustainable urban development. These targets cover carbon neutrality, greenhouse gas emissions (to be cut by eighty percent by 2025 compared to 1990 levels), a zero-waste circular economy by 2050, protection of natural resources including surface water and ground water, and sustainable transport, such as walking, cycling, and public transport.

Lahti’s 1.5 Degree Lifestyle Project is aimed at reducing the carbon footprint of families while collecting information on how municipal authorities can support sustainable lifestyles. This pilot project has helped many families in the city—even though many were already leading sustainable lifestyles—to reduce their carbon footprint by around nine percent.

The city also raises awareness among the next generation by making its schools and kindergartens energy efficient, a program that began in 2011 with the installation of energy measurement devices.

Sustainable Energy Advancements

In Lahti, the former coal fired Kymijärvi I power plant has now been replaced with a new bioenergy plant called Kymijärvi III. The city was the first in Finland to abandon coal with the new plant being fueled by recycled and local certified wood. This changeover has helped to reduce Lahti’s carbon emissions from energy by 600,000 metric tons per year.

Lahti has another green power plant called Kymijärvi II, which runs on solid recoverable fuel (SRF). The fuel is obtained from waste that would otherwise go to landfill. It is gasified, cooled, and cleaned and then combusted, producing about 280-300 GWh of electricity as well as 680-700 GWh of heat annually. The plant, the world’s first SRF gasification plant, is owned and operated by Lahti Energia Oy, a company owned directly by the city. The technology it utilizes was supplied by Finnish company Valmet Technologies Oy.

Beyond the Award, Lahti Leads for a Greener Future

Lahti’s comprehensive approach to sustainability was the main factor that led to the city being awarded the 2021 European Green Capital Award by a unanimous vote. Lahti performed strongly across a number of key environmental indicators, from air quality to waste, green growth, green innovation, and governance. Beyond the award, Lahti continues to exemplify an awareness of the urgency of the global climate crisis. Lahti has set an advanced environmental target to be carbon neutral by 2025—ten years ahead of Finland’s national target and twenty-five years ahead of the European Union’s 2050 goal.


*Robin Whitlock is an England-based freelance journalist specializing in environmental issues, climate change, and renewable energy, with a variety of other professional interests including green transportation.


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