Paper co-authors: Eliška Krkoška Lorencová, Silvia Ferrini, Davina Vačkářová
Summary: The impacts of climate change on urban life require response in terms of adaptation planning. We investigated perceptions of and economic preferences for urban climate adaptation through nature-based solutions (NBS) in Prague and found that: (i) increased use of NBS is likely to generate significant economic public value; (ii) people perceive the species diversity of the NBS measures positively; (iii) NBS implemented in public spaces are preferred over those implemented on public buildings; and that (iv) negative experience with heat waves is likely to lead to stronger support for adaptation policy through NBS.
Climate change is influencing the quality of life in cities in Europe and globally. Heat waves in particular are a concern as they endanger health of vulnerable population (especially children and the elderly) and decrease quality of life for all urban citizens with possible detrimental effects on productivity and economic production. It is becoming increasingly clear that cities must protect people from extreme heat. Vulnerability to extreme heat—an indicator developed by The Lancet countdown initiative on the health impacts of climate change—has been rising worldwide since 1990, with Europe being the most vulnerable continent particularly due to its ageing population, and because the majority of its population lives in cities. In the period between 1991 and 2015, heat waves were the deadliest extreme weather events in Europe.As the new IPCC report states, it is virtually certain that hot extremes such as heat waves have become more frequent and intense across most of the world since the 1950s; similarly the recent heat wave in North America was ‘virtually impossible’ to happen without climate change.
In order to respond to these risks, cities are increasingly developing adaptation plans that complement their mitigation activities. In contrast to climate mitigation—whereby the goal is to take measures that decrease green house gas emissions and hence decrease the extent of climate change—adaptation to climate change aims to help to cope with the impacts of climate change which include flash floods, storm surges or heat waves. Nature based solutions (NBS) can contribute to both adaptation and mitigation and potentially provide cost-effective solutions for urban issues. They focus on the multi-functionality of green and blue infrastructure interventions and help to address multiple societal challenges in cities and landscapes. NBS include a wide range of measures such as green roofs and facades, street trees, rain gardens, urban gardens, permeable surfaces and infiltration strips (see Table 1 for examples), but also larger-scale projects such as urban parks, green corridors or rivers (see e.g. Urban Nature-based Solutions for examples from the world).
But do citizens support nature-based adaptation planning? And if so, can we understand the preferences for NBS policies in such a way that would be useful to urban planners? Precisely these questions were the drivers of a new study from our department, recently published in journal Landscape and Urban Planning. The study used an online survey instrument that investigated the perception of and economic preferences for adaptation to climate change through nature-based solutions in Prague to inform its planning policy. In the first part of the survey, we investigated the perceptions of climate change and heat waves. Our sample (n = 525) is clearly worried about the changing climate, and the majority perceive it as a risk for themselves, the neighbourhoods they live in, the city of Prague and future generations (see Fig 1.). Heat waves are not perceived well; 63% of the sample experience the adverse effects of heat waves (48% do not feel well, 15% perceive a negative effect of heat waves on their health – see Fig. 2), and a significant majority of the sample perceives heat waves as a risk to Prague and the current quality of life in the city (79%).
In the second part of the survey, the study employed a choice experiment. This is an economic technique in which survey respondents are repeatedly asked to choose between alternative scenarios of changes and staying with the current situation; in this study, the proposed change was a policy that would lead to an increase use of six commonly used nature-based solutions (as per Table 1 above) in public spaces and on public buildings across the city. The proposed policy changes varied in their characteristics: where the NBS would be located (more in public spaces, more on public buildings, or evenly implemented), what the species composition of the NBS would be (single species, few species, or many species – think here of varying species of trees or grass strips composed of different flowers), and what the potential costs such a policy change would imply for the respondents in terms of increased municipal charges. The respondents always had the option not to choose any of the changes and to opt to stay with the current situation with no implied costs instead. Using statistical methods to analyse the repeated choices made by the representative sample of Prague respondents, we were able understand what the important aspects of the NBS policy are for Prague citizens, and whether the respondents are willing to pay for the proposed changes.
There are four major messages that arose from the analysis. Our results showed that:
- the NBS policy is widely supported by the public over the status quo, and that this preference is mirrored in the citizens’ concerns about climate change and the risks posed by heat waves in particular,
- species diversity matters in the portrayed scenarios, suggesting that (bio)diverse NBS generate additional public value over single-species measures and that policy which targets biodiversity may gain support,
- implementation of NBS in public spaces (e.g., street trees, rain gardens) is preferred over measures implemented on public buildings (green roofs and facades),
- adverse experiences with heat waves have increased support and willingness to pay for the policy.
The presented results provide evidence that adaptation planning through NBS is likely to generate significant economic public value, which is expected to increase with the intensifying effects of climate change.
The final part of the survey focused on the perception of individual NBS and their benefits. Regarding the latter, over 70% of the respondents rated air quality, microclimate regulation and water retention as the most important benefits of urban NBS, justifying our inquiry into the use of NBS for climate adaptation (see Fig.3). According to the respondents, NBS should focus both on the reduction of temperatures during heat waves and on storm water management (57%) rather than on either heat waves or storm water management only (30% and 13%, respectively). Regarding individual NBS interventions, the respondents were asked which of the proposed interventions they would like to see implemented in Prague or their neighbourhood (see Fig. 4). The highest scores were given to street trees and rain gardens (57% and 47%, respectively), followed by permeable surfaces (24.5%), green facades (20%), green roofs (15.3%) and infiltration strips (14.5%).
As adaptation planning, including the use of NBS, will shape how the cities we live in look in the future, it is important that the public is involved. Our survey showed that this is something our respondents support. Over half of our sample would be interested in participating in adaptation planning in their municipalities. The most preferable form of such participation would be via surveys (71%) and other online formats such as interactive maps (48%), while in-person—and more demanding—formats, such as focus groups, workshops or seminars for the public were of interest to around third of our respondents.
The use of blue-green measures and NSB feature in the new EU Strategy on Adaptation to Climate Change, while cities over 20,000 inhabitants were called upon to develop Urban Greening plans in the new EU Biodiversity Strategy. Looking into the future, it is clear from our research that having more nature in Prague designed for multiple purposes is likely to be supported by the public and can create significant public value. The city states in its implementation plan for 2020-2024 of the Adaptation Strategy that NBS and ecosystem-based adaptation measures should be used primarily, where possible. Similarly, guidelines to improve the care for street trees have been developed recently, reflecting the fact that many street trees are in a dire shape. Looking into the future, we hope that Prague (and other cities in the Czech Republic, EU and beyond) will not only become a city that is more resilient to climate change, but also a greener city that welcomes nature back into its heart.
Do you want to read more on topics related to urban sustainability, nature-based solutions and climate adaptation? See these previous blog posts:
- Started from the bottom: a new track for strategic green space planning in cities?
- What is the value of a tree’s shadow?
- Making re-naturalisation of cities a common practice
- Getting a grasp on urban challenges and futures in face of the climate crisis: The collaborative scenario-based techniques.
- Urban ecosystem services in the light of population needs: Why do they matter to urban planning?