Towards urban water sustainability: Analyzing management transitions in Miami,Las Vegas,and Los Angeles

As climate change challenges the sustainability of existing water supplies, many cities must transition toward more sustainable water management practices to meet demand. However, scholarly knowledge of the factors that drive such transitions is lacking, in part due to the dearth of comparative analyses in the existing transitions literature. This study seeks to identify common factors associated with transitions toward sustainability in urban water systems by comparing transitions in three cases: Miami, Las Vegas, and Los Angeles. For each case, we develop a data-driven narrative that integrates case-specific contextual data with standardized, longitudinal metrics of exposures theorized to drive transition. We then compare transitions across cases, focusing on periods of accelerated change (PoACs), to decouple generic factors associated with transition from those unique to individual case contexts. From this, we develop four propositions about transitions toward sustainable urban water management. We find that concurrent exposure to water stress and heightened public attention increases the probability of a PoAC (1), while other factors commonly expected to drive transition (e.g. financial stress) are unrelated (2). Moreover, the timing of exposure alignment (3) and the relationship between exposures and transition (4) may vary according to elements of the system’s unique context, including the institutional and infrastructure design and hydro-climatic setting. These propositions, as well as the methodology used to derive them, provide a new model for future research on how cities respond to climate-driven water challenges.     

Success and failure of grassroots innovations for addressing climate change: The case of the Transition Movement

Grassroots innovations emerge as networks generating innovative solutions for climate change adaptation and mitigation. However, it is unclear if grassroots innovations can be successful in responding to climate change. Little evidence exists on replication, international comparisons are rare, and research tends to overlook discontinued responses in favour of successful ones. We take the Transition Movement as a case study of a rapidly spreading transnational grassroots network, and include both active and non-active local transition initiatives. We investigate the replication of grassroots innovations in different contexts with the aim to uncover general patterns of success and failure, and identify questions for future research. An online survey was carried out in 23 countries (N = 276). The data analysis entailed testing the effect of internal and contextual factors of success as drawn from the existing literature, and the identification of clusters of transition initiatives with similar internal and contextual factor configurations. Most transition initiatives consider themselves successful. Success is defined along the lines of social connectivity and empowerment, and external environmental impact. We find that less successful transition initiatives might underestimate the importance of contextual factors and material resources in influencing success. We also find that their diffusion is linked to the combination of local–global learning processes, and that there is an incubation period during which a transition initiative is consolidated. Transition initiatives seem capable of generalising organisational principles derived from unique local experiences that seem to be effective in other local contexts. However, the geographical locations matter with regard to where transition initiatives take root and the extent of their success, and ‘place attachment’ may have a role in the diffusion of successful initiatives. We suggest that longitudinal comparative studies can advance our understanding in this regard, as well as inform the changing nature of the definition of success at different stages of grassroots innovation development, and the dynamic nature of local and global linkages.     

Elaborating global private meta-governance: An inventory in the realm of voluntary sustainability standards

Voluntary sustainability standards and certification schemes are expanding in a variety of economic sectors. The relatively uncoordinated coexistence of multiple competing schemes has created a very fragmented governance system. One way to analytically approach the search for solutions to this fragmentation is grasped with the relatively new concept of meta-governance. Meta-governance as we understand it draws attention to the management of plurality with the aim to induce more coherence in the governance of an issue area. In political science, meta-governance has mainly been attributed to governmental authorities. However, over the past decade, a number of voluntary standards setters have – with or without the support of UN agencies – started to address the need for meta-governance as well. Their efforts generally entail the coming together of a number of frontrunner schemes and the organizations backing them to jointly address the challenges their self-created regulatory systems face and produce greater coherence among their efforts. This paper studies private meta-governance attempts in the fields of fair labor (JO-IN), sustainable tourism (GSTC), and organic agriculture (ITF), as well as a meta-governance initiative that aims to improve the credibility of private standards as governance mechanisms (ISEAL Alliance). Based on document analysis and interviews we analyze how these meta-governance initiatives have given shape to their aspirations, how successful their efforts have been in effecting change, and what determining factors are. From the empirical research, we distil some more general lessons and insights about the politics and practice of private meta-governance.     

Water on an urban planet: Urbanization and the reach of urban water infrastructure

Urban growth is increasing the demand for freshwater resources, yet surprisingly the water sources of the world's large cities have never been globally assessed, hampering efforts to assess the distribution and causes of urban water stress. We conducted the first global survey of the large cities’ water sources, and show that previous global hydrologic models that ignored urban water infrastructure significantly overestimated urban water stress. Large cities obtain 78 ± 3% of their water from surface sources, some of which are far away: cumulatively, large cities moved 504 billion liters a day (184 km³ yr⁻¹) a distance of 27,000 ± 3800 km, and the upstream contributing area of urban water sources is 41% of the global land surface. Despite this infrastructure, one in four cities, containing $4.8 ± 0.7 trillion in economic activity, remain water stressed due to geographical and financial limitations. The strategic management of these cities’ water sources is therefore important for the future of the global economy.     

Trees,forests and water: Cool insights for a hot world

Forest-driven water and energy cycles are poorly integrated into regional, national, continental and global decision-making on climate change adaptation, mitigation, land use and water management. This constrains humanity’s ability to protect our planet’s climate and life-sustaining functions. The substantial body of research we review reveals that forest, water and energy interactions provide the foundations for carbon storage, for cooling terrestrial surfaces and for distributing water resources. Forests and trees must be recognized as prime regulators within the water, energy and carbon cycles. If these functions are ignored, planners will be unable to assess, adapt to or mitigate the impacts of changing land cover and climate. Our call to action targets a reversal of paradigms, from a carbon-centric model to one that treats the hydrologic and climate-cooling effects of trees and forests as the first order of priority. For reasons of sustainability, carbon storage must remain a secondary, though valuable, by-product. The effects of tree cover on climate at local, regional and continental scales offer benefits that demand wider recognition. The forest- and tree-centered research insights we review and analyze provide a knowledge-base for improving plans, policies and actions. Our understanding of how trees and forests influence water, energy and carbon cycles has important implications, both for the structure of planning, management and governance institutions, as well as for how trees and forests might be used to improve sustainability, adaptation and mitigation efforts.     

The influence of urban development dynamics on community resilience practice in New York City after Superstorm Sandy: Experiences from the Lower East Side and the Rockaways

While (urban) resilience has become an increasingly popular concept, especially in the areas of disaster risk reduction (DRR) and climate change adaptation (CCA), it is often still used as an abstract metaphor, with much debate centered on definitions, differences in approaches, and epistemological considerations. Empirical studies examining how community-based organizations (CBOs) “practice” resilience on the ground and what enables these CBOs to organize and mobilize around resilience are lacking. Moreover, in the growing context of competitive and entrepreneurial urbanism and conflicting priorities about urban (re)development, it is unclear how urban development dynamics influence community-based resilience actions. Through empirical research conducted on the Lower East Side, a gentrifying neighborhood in Manhattan, and in Rockaway, a socio-spatially isolated neighborhood in Queens, we investigate community organizing of low-income residents for (climate) resilience in a post-disaster context. Results show that both the operationalization of resilience – how resilience is “practiced” – and the community capacity to organize for the improved resilience of low-income residents are strongly influenced by pre-existing urban development dynamics and civic infrastructure – the socio-spatial networks of community-based organizations – in each neighborhood. The Lower East Side, with its long history of community activism and awareness of gentrification threats, was better able to mobilize broadly and collectively around resilience needs while the more socio-spatially isolated neighborhoods on the Rockaway peninsula were more constrained.     

辽宁北部典型流域水生态功能区水生态安全评价

基于流域水生态功能分区的水生态安全评价是指导流域水生态“分类、分区”综合管理的前提,本文在流域中小尺度上依据水生态空间格局分异的自然特征和社会属性,以辽河流域的清河和凡河支流为对象,在流域水生态功能三级分区的基础上,运用“压力-状态-响应模型”（PSR）,通过对流域社会经济压力指标、环境压力指标、城市发展指标、资源环境发展指标、投资指标、治理指标等因素分析,筛选出13个评价指标。利用生态安全综合指数法,将流域水生态安全划分为极不安全、不安全、基本安全、安全、非常安全五个级别。其中,清河流域Ⅳ-5-9、Ⅳ-5-10、Ⅳ-5-11、Ⅳ-5-12、Ⅳ-5-14区处于基本安全,Ⅳ-5-8、Ⅳ-5-13属于不安全;凡河流域4个水生态功能三级区中,Ⅳ-5-1、Ⅳ-5-2、Ⅳ-5-3区属于基本安全、Ⅳ-5-4区为较安全。基于水生态功能分区的水生态安全评价和级别划分可为辽河流域水生态保护与流域生态管理提供科学依据。     

全球定位系统的可降水量资料在北京地区快速更新循环系统中的同化试验

针对发生于2006年8月和2007年6-8月的28次降水过程,在3 h快速更新循环同化预报系统平台上分别进行了有无同化局地GPS可降水量资料的试验.结果表明,局地GPS可降水量的同化可以使模式对大阈值降水的时段、强度和落区的预报性能均获得全面的提高,此现象在模式积分最初的0-6小时表现得更为明显.由于同化所用的GPS可降水量观测资料主要集中在极为局地的京津冀地区,而且GPS-PWV资料的同化仅能对模式中的水汽含量发生影响,因此该资料的同化与否并不能为模式总体预报性能带来明显差异.但从以54511测站为代表的北京地区局地常规要素预报效果来看,快速更新循环的同化方式能使高时空分辨率的GPS可降水量在北京局地的同化效果得以累积,并为气象要素在局地的预报效果带来显著的正面影响.通过对一次强对流个例进行分析可以发现,以快速更新循环的方式可以同化较高时间频率的GPS可降水量观测,从而对模式大气的初始湿度条件起到持续累积的影响.在一定的动力和热力条件下,由GPS可降水量同化带来的累积的模式大气增湿也有望在模式中形成利于局地对流形成和发展的环境,提高模式对局地对流的预报水平.     

On the scavenging of SO2 by cloud and raindrops: II. An experimental study of SO2 absorption and desorption for water drops in air

For the purpose of testing our previously described theory of SO₂ scavenging a laboratory investigation was carried out in the UCLA 33 m long rainshaft. Drops with radii between 250 and 2500 m were allowed to come to terminal velocity, after which they passed through a chamber of variable length filled with various SO₂ concentrations in air. After falling through a gas separating chamber consisting of a fluorocarbon gas the drops were collected and analyzed for their total S content in order to determine the rate of SO ₂ absorption.The SO₂ concentration in air studied ranged between 1 and 60% (v). Such relatively large concentrations were necessary due to the short times the drops were exposed to SO₂ in the present setup. The present experimental results were therefore not used to simulate atmospheric conditions but rather to test our previously derived theory which is applicable to any laboratory or atmospheric condition. Comparison of our studies with the results from our theory applied to our laboratory conditions led to predicted values for the S concentration in the drops which agreed well with those observed if the drops had radii smaller than 500 m. In order to obtain agreement between predicted and observed S concentrations in larger drops, an empirically derived eddy diffusivity for SO₂ in water had to be included in the theory to take into account the effect of turbulent mixing inside such large drops.In a subsequent set of experiments, drops initially saturated with S (IV) were allowed to fall through S-free air to determine the rate of SO ₂ desorption. The results of these studies also agreed well with the results of our theoretical model, thus justifying the reversibility assumption made in our theoretical models.In a final set of experiments, the effects of oxidation on SO₂ absorption was studied by means of drops containing various amounts of H₂O₂. For comparable exposure times to SO₂, the S concentration in drops with H₂O₂ was found to be up to 10 times higher than the concentration in drops in which no oxidation occurred.