It has become assumed that most humans will live in cities going forward and that they can be made to mitigate their environmental impacts. These assumptions come out of a period that has enjoyed ample energy from fossil fuels, and invisible to most, enormous resource flows from non-urban areas. For cities to reduce their GHGs, that means they must be reduced in resourcing areas, challenging our current deep dependence on fossil energy. This perspective suggests there is a need for new research that investigates how to reduce GHGs in resourcing areas through intensive agroecology, how to build climate appropriate, low embedded GHG emissions buildings, low energy technologies, to move to a future where we begin to live within the limits of the planet.

Urban forests are increasingly being seen as an important infrastructure that can help cities remediate their environmental impacts. This work reports on the first steps in implementing a million tree program in Los Angeles and the ways such a biogenic—living—infrastructure has been approached. Numbers of studies have been done to quantify the benefits of urban forests, but little has been written on the process of implementing urban tree planting programs. The investigative methods were primarily qualitative, involving interviews, attending meetings and conducting literature reviews. Results indicate that multiple nonprofit and city agency programs are involved in planting and maintaining trees and this has required coordination among groups that here-to-fore were unaccustomed to having to collaborate. The main finding that emerge from this research is that the implementation of such a program in Los Angeles is more complicated than it may seem due to several interacting factors: the need to rely on multiple public and private organizations to put trees into the ground and to maintain them; coordination of these multiple efforts must be centralized, but requires a great deal of time and effort and maybe resisted by some of the partners; funding for planting and long term maintenance must be pieced together from multiple sources; acceptance of trees by residents varies by neighborhood as does tree canopy cover; appropriate nursery supply can be limited; the location of the program within the city administration is determined by who initiates the program.

I argue that the tension between cities and nation states go through the countryside, or rural areas, at least in the U.S. Further, cities are decidedly constrained in their abilities to effectuate many of the changes associated with them: addressing climate change, economic inequality and more. What is missing is the way in which rural alienation from economic prosperity plays out politically.

Cities are human creations where many of the emissions causing climate change originate. Every aspect of daily life in cities, which spans buildings, transit, food, energy, and water, relies on fossil fuels that materially contribute to climate change. This paper explores the need for research to better uncover the processes driving urbanization in order to develop novel ways to mitigate climate impacts on Earth. Areas of fruitful research include better quantification of teleconnections between cities and their hinterlands and coupling those to the socio-economic drivers and organization of those relationships; the financialization of much urban policy; understanding where cities fit in the global economic order and their role in generating economic growth, and the ways in which they are also seen as leaders of sustainability and climate actions, but constrained in so-doing by the nested and tiered layers of institutions they operate within. This paper concludes by outlining ways for cities to transition toward nurturing human well-being and reducing their impacts on planetary processes resulting in the proposed new Earth epoch – the Anthropocene.

Cities have become a central focus for questions of sustainability futures. Most discussion has to do with their activities and how they are governed and the strategies to reduce their environmental impacts while increasing their equity. Yet few ask yet a more fundamental question: what are cities for and how might that affect their futures? This commentary raises questions about the role of cities especially in a potential post carbon age.

California is widely seen as a climate and environmental policy leader in the U.S. and beyond. However, allowing local land use decisions to proceed as usual represents a major gap in the state's climate policy framework. Climate mitigation rules and formulae are utilized to claim zero net emissions for large-scale land development at the urban fringe. Such developments continue to destroy habitats and radically transform landscapes. Newhall Ranch, a subdevelopment at the edge of urbanized Los Angeles County, has claimed emissions offsets such that the development of 60,000 homes will have less than zero greenhouse gas emissions. Offsets largely rely on using disadvantaged communities, and significant threats to endangered species on site are compensated by payments to the project's environmental opponents. The net result is land development as usual, with a veneer of solarization and investments in GHG mitigation projects with poor quantification and verification. This situation demonstrates the enduring structures of land use development that drive GHG emissions and environmental change, and calls for stronger requirements for local compliance with state emissions-reductions targets.

Henri Laborit, a neuro-biologist and surgeon specializing in stresses to organisms and a member of the Groupe des Dix, is the author of an interdisciplinary pedagogical and scientific experiment with urban planners at the University of Paris-Vincennes. His book L'Homme et la ville (1971) describes the city as a complex eco-system in which man exercises dominant relations in history (class, race, nation, etc. relationships) under the control of an archaic brain. But can the city be compared to a living organism? Does it have a brain? Is it a machine? The systemic approach and the cybernetic theory, shared by other members of the Groupe des Dix, allows an analysis of complex systems, from cellular societies to human societies (Edgar Morin), from the microscope to the macroscope (Joël de Rosnay). But the city system remains a human "production", an anthropo-ecosystem, while its evolutionary "trend"is made up of social, economic and ecological equilibria. What organizational models are able to regulate a sustainable urban metabolism?.

Cities across the globe manage stormwater to enhance water supplies. Capturing and using stormwater in urban watersheds can have benefits for groundwater recharge, reduced pollutant loading in downstream watersheds, and habitat management. In California, metropolitan areas in the southern coastal regions of the state have for decades captured an average of 493 Million Cubic Meters (400,000 acre-feet) of runoff annually to recharge groundwater. But in a state with highly managed watersheds and seasonal precipitation, capturing stormwater for water supply goals can affect urban streamflows. Using a model with simulation and optimization of regional urban water resources management in Los Angeles County (Artes), we analyze the potential effects of increasing stormwater capture and infiltration on urban streamflow volumes. Results indicate that for many watersheds in LA, further increasing stormwater capture and use would significantly reduce urban streamflow volumes, especially in downstream basins. But in some basins, streamflows are increased to preferentially direct water to existing stormwater capture basins. Results illustrate potential tradeoffs in water supply, in-stream water flows, and aquatic habitat that must be considered when looking to increase use of local water sources through more stormwater capture.

The Public Interest Energy Research (PIER) Program of the California Energy Commission has recognized the importance of sustainable communities to improving the efficiency, cost, and social and environmental impacts of energy use in California.In order for sustainable communities research, development, and demonstration (RD&D) funded by the PIER program to be effective, it is important to understand and optimize the energy-related aspects of land use planning and community design. In this white paper, a research teamfrom the UCLA Institute of the Environment identifies a unifying framework for sustainable communities researchby the PIER Program that explicitly considers sustainability with respect to energy production and use in California communities. In this context, a sustainable community is one that minimizes throughputs of energy and materials through efficient and socially sensitive production, distribution, use, and reuse of those materials and energy. The research team identifies an urban metabolism framework as the most effective framework to meet the criteria and needs of the PIER Program. Ideally, this framework for sustainable communities will guide and integrate research efforts among the PIER Program’s seven subject areas so that sustainable communities RD&D funded by the PIER Program can provide optimal benefits to California.