Åsa Gren

A quantitative review of urban ecosystem service assessments: concepts, models, and implementation.

Although a number of comprehensive reviews have examined global ecosystem services (ES), few have focused on studies that assess urban ecosystem services (UES). Given that more than half of the world’s population lives in cities, understanding the dualism of the provision of and need for UES is of critical importance. Which UES are the focus of research, and what types of urban land use are examined? Are models or decision support systems used to assess the provision of UES? Are trade-offs considered? Do studies of UES engage stakeholders? To address these questions, we analyzed 217 papers derived from an ISI Web of Knowledge search using a set of standardized criteria. The results indicate that most UES studies have been undertaken in Europe, North America, and China, at city scale. Assessment methods involve bio-physical models, Geographical Information Systems, and valuation, but few study findings have been implemented as land use policy.

Does aquaculture add resilience to the global food system

Aquaculture is the fastest growing food sector and continues to expand alongside terrestrial crop and livestock production. Using portfolio theory as a conceptual framework, we explore how current interconnections between the aquaculture, crop, livestock, and fisheries sectors act as an impediment to, or an opportunity for, enhanced resilience in the global food system given increased resource scarcity and climate change. Aquaculture can potentially enhance resilience through improved resource use efficiencies and increased diversification of farmed species, locales of production, and feeding strategies. However, aquaculture’s reliance on terrestrial crops and wild fish for feeds, its dependence on freshwater and land for culture sites, and its broad array of environmental impacts diminishes its ability to add resilience. Feeds for livestock and farmed fish that are fed rely largely on the same crops, although the fraction destined for aquaculture is presently small (∼4%). As demand for high-value fed aquaculture products grows, competition for these crops will also rise, as will the demand for wild fish as feed inputs. Many of these crops and forage fish are also consumed directly by humans and provide essential nutrition for low-income households. Their rising use in aquafeeds has the potential to increase price levels and volatility, worsening food insecurity among the most vulnerable populations. Although the diversification of global food production systems that includes aquaculture offers promise for enhanced resilience, such promise will not be realized if government policies fail to provide adequate incentives for resource efficiency, equity, and environmental protection.

Urban ecosystem cervices

We explore the potential of urban ecosystem services for improving resilience and quality of life in cities. First, we classify and categorize important ecosystem services and disservices in urban areas. Second, we describe a range of valuation approaches (cultural values, health benefits, economic costs, and resilience) for capturing the importance of urban ecosystem service multiple values. Finally, we analyze how ecosystem service assessment may inform urban planning and governance and provide practical examples from cities in Africa, Europe, and America. From our review, we find that many urban ecosystem services have already been identified, characterized and valued, and have been found to be of great value and importance for human well-being and urban resilience. We conclude that the use of the concept of urban ecosystem services can play a critical role in reconnecting cities to the biosphere, and reducing the ecological footprint and ecological debt of cities while enhancing resilience, health, and quality of life of their inhabitants.

Operationalising a social–ecological system perspective on the Arctic Ocean

We propose a framework to support management that builds on a social–ecological system perspective on the Arctic Ocean. We illustrate the framework’s application for two policy-relevant scenarios of climate-driven change, picturing a shift in zooplankton composition and alternatively a crab invasion. We analyse archetypical system dynamics between the socio-economic, the natural, and the governance systems in these scenarios. Our holistic approach can help managers identify looming problems arising from complex system interactions and prioritise among problems and solutions, even when available data are limited.

Valuation of oil spill risk reductions in the Arctic

ABSTRACT In this study, data from a contingent valuation (CV) study in Lofoten, Norway, are used to assess the value of ecosystem services at risk from oil spills in the Arctic. It is investigated to which extent subjective opinion about the probability of a potential oil spill steers respondents’ willingness to pay (WTP) for reducing risk. The respondents’ preferences are analysed for ecosystem services. Finally, differences in WTP for two hypothetical spill scenarios are considered: one where measures are taken to reduce the probability of a spill and one where measures are taken to reduce the probability and impacts in the event of an accident. The findings indicate that measures should focus on alleviating the impacts of oil spills on ecosystem services generally, rather than on any specific ecosystem service. Furthermore, respondents’ perception of risk is higher than the estimated objective risk. The findings also suggest that respondents are more concerned about preventing the occurrence of oil spill accidents (usually considered to be more frequent than they actually are) compared to preventing the impacts of a spill. One policy implication is to focus more on policies that decrease the probability of spills than on policies that decrease the subsequent ecological impact.

Capturing the value of green space in urban parks in a sustainable urban planning and design context: pros and cons of hedonic pricing

Sixty percent of the land that will be urban in 2030 has yet to be built. Contemporary urban development is unsustainable and focus is on building dense, often at the expense of urban green space (UGS), at the same time as our understanding of links between green spaces and human well-being, especially health, is increasing. There is a need to better understand and analyze human well-being qualities of UGS in a planning context. Our aim is to increase this understanding by analyzing the pros and cons of hedonic pricing in this context. Hedonic pricing is commonly used for analyzing benefits associated with UGS to make them more visible and to provide support for urban planning. However, the validity of this approach has been questioned. To increase the accuracy of a hedonic pricing method we incorporate state-of-the-art methods to assess the value of public parks in a case study. Although our results suggest that urban parks indeed have a positive effect on property value and that this effect tends to increase with reduced distance to the parks, the hedonic pricing information is not enough to make well-advised decisions in a sustainable planning context. We thus suggest (1) including and quantifying additional health benefit dimensions and (2) replacing straight-line measures with an axial line step distance measure, to better capture accessibility. To better capture the range of benefits generated by urban parks, irrespective of whether these benefits are enjoyed in direct relation to the park or not, we suggest complementing hedonic pricing via (3) applying an ecosystem service lens, thus also improving the accuracy of trade-off and synergy analysis Also, a sustainable planning approach will benefit from (4) taking the surrounding land use configuration into account for optimizing the different values of urban parks.

How smart is smart growth? Examining the environmental validation behind city compaction

Smart growth (SG) is widely adopted by planners and policy makers as an environmentally friendly way of building cities. In this paper, we analyze the environmental validity of the SG-approach based on a review of the scientific literature. We found a lack of proof of environmental gains, in combination with a great inconsistency in the measurements of different SG attributes. We found that a surprisingly limited number of studies have actually examined the environmental rationales behind SG, with 34% of those studies displaying negative environmental outcomes of SG. Based on the insights from the review, we propose that research within this context must first be founded in more advanced and consistent knowledge of geographic and spatial analyses. Second, it needs to a greater degree be based on a system’s understanding of urban processes. Third, it needs to aim at making cities more resilient, e.g., against climate-change effects.