Department of Design

Helsinki Biochar Project

The City of Helsinki explores the practical pathways for improved carbon sequestration, circular waste systems, and thriving urban vegetation via increasing the use of biochar on selected demonstration sites across public green structures. During years 2022-23, different kinds of organic waste materials are being tested as potential feedstocks for manufacturing local biochar. The project is set out to spread awareness about the benefits of, and providing practical know-how of using biochar among the city administration and citizens.
Biochar samples sorted according to size
Biochar samples sorted according to size

Biochar to reach a climate- neutral city

The city of Helsinki has set an ambitious program to be carbon neutral by 2030, and all means necessary need to be taken to achieve that goal. Emissions are being cut throughout the city and to reach the target, 20 % of emissions, equalling to 702 kt CO2- eq., can be compensated. By 2040, the city will offset all remaining emissions through carbon sinks located within the city´s geographical boundaries, which is where biochar is needed

In addition to a means to sequester carbon, biochar has potential to play a role in climate adaptation strategies. Biochar can be added as a soil amendment changing the absorption capacity and structure of the soil. Increasing the capacity of urban soils to be more resilient to extreme weather events, such as storms and prolonged periods of drought, could potentially serve as one of multiple means for urban climate adaptation.


Intended experimental sites in Helsinki

Currently, a number of sites that are currently being designed for construction have been selected to be amended with biochar. The list is evolving, and the plans are subject to change. The information in the list is constantly being updated.

Events related to the Helsinki Biochar Project

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Upcoming events

Biochar. In the City?
On the 16th of March had a public discussion about the role of biochar in the climate work of cities. The project responsibles, Mikko Jalas (Aalto) and Susanna Kankaanpää (Helsinki) presented their current views and answered to questions from the public. The event was a part of NODUS Talks continuum at the Helsinki Design Museum and its recording can be viewed on Aalto Youtube channel.

Graphic design. On the right side of the visual there is a volcanic landscape with beautiful rocky pathway towards a mountain. Left side of the visual is fading to black. On the top left corner: Sustainability Science Days text is displayed with Swear Display font, and Aalto University and Helsinki University logos below on the left hand side of the visual.
Upcoming events

Join us on the upcoming Sustainability Science Days 2023 in the session "Scaling Up Urban Carbon Sinks with Urban Green Infrastructure". The Sustainability Science Days is an international, multi-day conference organised jointly by Helsinki Institute of Sustainability Science (HELSUS) and Aalto University on 23 - 26th of May 2023.

The session brings together climate, material, soil and social scientists; landscape architects and urban planners; practitioners and businesses; and municipalities and governmental bodies. The aim is to bring forward academic knowledge and practices on the conditions and current ways of scaling up urban carbon sinks and developing carbon smart Urban Green Infrastructure for development of municipal strategies and decision-making, planning, as well as construction and maintenance practices. 

The Helsinki Biochar Project builds on previous collaboration projects on biochar

Carbon Lane -project

Carbon Lane (CarLa) is an EIT Climate-KIC funded project which takes place during 2019. The project explores practical carbon drawdown solutions for urban green areas

Illustration of a tree in soil with details of roots, carbon, nutrients

Hiilipuisto - Carbon Park

Hiilipuisto project launches scientific monitoring of biochar-based planting soils and develops sustainable practices in the green building sector.

Kuva: Esko Salo
City of Helsinki
Aalto University
Helsinki Region Environmental Services HSY
VTT Technical Research Centre of Finland Ltd

Project responsibles

  • Susanna Kankaanpää, Helsinki Urban Environment Division, Climate Unit
  • Prof. Mikko Jalas, Aalto University

Contact persons:

  • Tuuli Markkanen, Project Coordinator, Aalto University tuuli.markkanen[at]
  • Will van Twuijver, Coordinator in citizen engagement, Aalto University, will.vantwuijver[at]

Funding and support from abroad

Bloomberg Philanthropies announced that seven cities from Europe and the United States will receive support to adopt Stockholm’s 2014 Bloomberg Philanthropies’ Mayors Challenge Winning Biochar Project, which turns plant waste from parks and homes into a charcoal-like substance that residents can then use in their yards and gardens to help combat climate change. 

Darmstadt, Helsingborg, Sandnes, Helsinki, Cincinnati, Lincoln, and Minneapolis, will receive funding, along with implementation and technical support from Bloomberg Philanthropies to develop city-wide biochar projects and engage residents in the fight against climate change. Participating cities will also benefit from robust best practice sharing and peer-to-peer networking to share lessons learned in implementing their efforts

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