1) Which are the main environmental and social challenges Aarhus is facing with?
Aarhus Municipality is facing rapid urban growth, with the number of inhabitants rising from the current 340,000 to additional 75,000 inhabitants by 2030. The urban strategy specifies the induced housing need for additional 50,000 housing units to be met through densification of the city to limit further sprawl.
The rapid growth poses a rising challenge to accommodate both nature, water and the built environment on limited space. It also challenges adequate solutions to the general negative tendencies with falling numbers of pollinators, wildlife and natural habitats.
At the same time projections of a future with increasing rainfalls, extreme weather events and higher ground water levels challenges the urban growth. Aarhus is centered partly in low laying areas of valleys and along the Aarhus Bay and therefore water becomes an increasing challenge for the city growth. The need of finding space for delaying excess water on the surface is challenged with a denser city with an increasing paved area.
2) Which actions is Aarhus city currently taking to address these challenges and which actors are involved?
Aarhus Municipality has several ambitious goals for enhancing the conditions for nature and biodiversity and for finding space to handle more water in the future.
One goal is to improve the quality and double the area of nature and biodiversity within 2030. An example of that is the new nature area Geding-Kasted Mose. The area is a wetland in the top of Egå River Valley and is grazed by water buffalos. It is situated close to the city serving both as recreational area, nature area and furthermore it has the potential to store water in case of extreme events.
Another goal is to double the forested area in Aarhus to 8000 ha. and at the same time protecting the groundwater and moving towards CO2-neutrality before 2030. Aarhus Municipality is in the coming years going to plant 500 ha of new forest new the village True together with the National Nature Department. The project is named True Forest for Everyone and has multiple purposes such as afforestation, groundwater protection, CO2-reuction and recreational purposes.
To face the expected increase in precipitation and rising ground water level the City Council have decided, that the public owned waste water company Aarhus Water A/S move towards a full separation of rainwater from the sewage system during the coming 50 – 70 years. Furthermore, Aarhus Water A/S is testing a new decision-making method for handling excess water on the surface and at the same time creating added values in a pilot area named Åbyhøj. The large-scale implementation of separating and handling rainwater on the surface also offers an opportunity to create more green and recreational spaces in the city.
Aarhus Municipality wants to strengthen the blue and green infrastructures in the future in a way that also improves the accessibility for the citizens to green and recreational areas both inside and outside the city. In 2021 the city council is expected to adopt a new Municipal Plan of Blue and Green Infrastructures. The aim of the plan is to support and reinforce the possibility of finding space for more green areas and for handling of surface water while the city is developing.
1) Which are the main environmental and social challenges Velika Gorica is facing with?
European cities give us plenty of inspiring examples on how to improve the urban environment, leading to better physical and mental health of their citizens, among others. Whether it is landscaping of new or expanding existing urban green space, new pedestrian or bicycle routes, creating habitats for urban biodiversity, or different health care measures, the city population is entitled to, and the city governments have a duty to ensure ecologically sound urban environment.
Many cities around the world are adapting to climate change, and a solution has been found in converting abandoned industrial sites, planting new trees, greening facades, rooftops and sidewalks to reduce the effect of thermal islands that can cause temperature differences between downtown and the environment by up to 12 degrees Celsius hot summer nights.
The city of Velika Gorica, like many other Croatian cities, does not exactly brag about activities of this magnitude, and in the media there are more and more “negative” news, such as the disappearance of Croatian forests and wagons full of logs that usually leave the country, just like its population. Despite this classic problem of most of the new member states of the European Union, the City of Velika Gorica continues to strive to adapt the city to the needs of the modern urban population, as well as to climate change, by greening the city’s public spaces for different groups of citizens.
2) Which actions is Velika Gorica currently taking to address these challenges and which actors are involved?
The City of Velika Gorica has a Commission for Green Public Areas with a goal to prevent the unnecessary removal of trees and other green plantations in public urban areas and to give advice to city’s administration on planning new plantations. Commission members receive requests from citizens, tenants’ representatives, presidents of local neighborhoods and settlements regarding the removal or evaluation of status of trees in green public areas. According to the request, the site is visited, expertly assessed and the decision is made on how the trees will be treated. In addition, the City is currently working on the first city’s green cadaster, which contains a list of all city’s greenery, stored in one place under the GIS system.
Another project worth mentioning is „Landscaping of gardens and construction of mini-recycling yards for schools and kindergartens in the City of Velika Gorica“, where elementary schools and kindergartens received support to design their school yards as permaculture gardens and construct composters and mini-recycling yards, allow the youngest to get in touch with nature, learn and adopt permaculture principles. The project was also supposed to integrate the establishment of local school „seed banks“, in which children would learn how to collect seeds and store them under right conditions. Unfortunately, at that time no funding for such project could have been found, so it has stopped at the level of a project proposal.
Within REGREEN project, Velika Gorica is going to explore possibilities to implement different “Nature Based Solutions” (NBS) for adaptation to climate change in the urban environment. The project will also help improve governance system, as the city administration aims to include citizens in planning, development and implementation of those solutions, which will fit beautifully with the aforementioned projects and city’s long-term intentions. Despite the climate change is already
inevitable, REGREEN project can contribute to creating a future for the sustainable development of the City of Velika Gorica and better living environment for all its citizens.
1) Which are the main environmental and social challenges Paris Region is facing with?
Paris Region, also called “Île-de-France”, is a province located in the north-central part of France. It includes the city of Paris and 1,275 municipalities around the capital-city. Paris region is the most populated province of France (20% of the French population but only 2% of France area). Twenty-three percent of the territory is urban cover (including 16% totally sealed). The outer parts of the Ile-de-France remain largely rural with agricultural landscapes (51% – mainly intensive open fields) and forests (24 %).
Although urbanization has slowed down over the last few years, the mean land take is still high (840 hectares per year) and occurs mostly on agricultural land. Moreover, half of wetlands and aquatic environments have shut down over the 20th century, grasslands and heathlands have decreased substantially, hedges and copses have almost disappeared in agriculture landscapes. Biodiversity loss in Paris Region rarely cause extinction of species, but the decline of several populations is increasing: between 25% and 40 % species are threatened . All of these changes have significant implications for ecosystem function and their ability to provide goods and services on which human well-being depends.
Simultaneously, climate change is a reality. The metropolitan area has faced several flood events in the past years (2016 and 2018) and strong heat waves (2013, 2018). Scenarios and forecasting models indicate an increasing number of imminent changes for Paris Region. According to Météo-France, climate change will result in an increase in overall global temperatures, an effect which will be particularly noticeable during the summer months especially in built up areas affected by the phenomenon of Urban Heat Islands
2) Which actions are Paris Region’s cities currently taking to address these challenges and which actors are involved?
An increasing number of municipalities are interested in nature-based solutions as a strategy towards resilience and a way to address both climate and biodiversity issues.
Nature-based solutions stand for the preservation, restoration or creation of ecosystems. When designed and managed properly, these NBS can provide multiple benefits, including habitats for biodiversity, carbon storage, water retention, pollution removal, etc., at low cost and with social benefits in terms of public health and well-being . Over the last decade, nature-based solutions have been studied by scientists and implemented by cities. Scientific papers as well as experiments in cities show that NBS can be very efficient.
Paris Region has launched in 2017 a “Green Plan” to create new green spaces and make them accessible to every citizens less than 15 minutes’ walk. Green spaces is one thing, but the ecological management of these green spaces is another important issue, to increase biodiversity and adapt these spaces to climate change: this includes zero use of pesticides and chemical fertilizers, but also encouraging native plants and low management. Since 2017, 67% of cities in Île-de-France has completely stopped using pesticide. In urban areas, we observed that the number of plant species has increased by 92% in just 7 years. Moreover, nearly one quarter of Paris and its inner suburbs’ green spaces have be awarded with an eco-label (named EcoJardin) for their ecological management.
Some municipalities in Paris region have also carried out river restoration and stream daylighting operations aiming in order to improve water quality in cities, reduce runoff, flood risk and create new habitats. In Sarcelles, a town north of Paris, the restoration of the Petit Rosne has provided interesting benefits for biodiversity and water regulation, including new recreative places for citizens.
The area of impervious surfaces in Paris are still very important. Thus, there is a huge opportunity to turn these impervious surfaces (concrete and asphalt) into natural habitats and nature-based solutions. Such a “depaving strategy” will be one of the axis developed by Paris ULL in REGREEN.
 Maxime Zucca, Grégoire Loïs, Audrey Muratet, Ophélie Ricci, 2019. Panorama de la biodiversité francilienne. ARB îdF, Paris. 40 pages.
 Note rapide | Les communes franciliennes s’engagent pour le « zéro pesticides » (2019)
 Muratet A., 2016. Etat de santé de la biodiversité en Île-de-France – Apport du programme de sciences participatives Vigie-Nature. Natureparif, Paris. 22 pages.