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Record climate extremes are reducing urban liveability, compounding inequality, and threatening infrastructure. Adaptation measures that integrate technological, nature-based, and social solutions can provide multiple co-benefits to address complex socioecological issues in cities while increasing resilience to potential impacts. However, there remain many challenges to developing and implementing integrated solutions. In this Viewpoint, we consider the value of integrating across the three solution sets, the challenges and potential enablers for integrating solution sets, and present examples of challenges and adopted solutions in three cities with different urban contexts and climates (Freiburg, Germany; Durban, South Africa; and Singapore). We conclude with a discussion of research directions and provide a road map to identify the actions that enable successful implementation of integrated climate solutions. We highlight the need for more systematic research that targets enabling environments for integration; achieving integrated solutions in different contexts to avoid maladaptation; simultaneously improving liveability, sustainability, and equality; and replicating via transfer and scale-up of local solutions. Cities in systematically disadvantaged countries (sometimes referred to as the Global South) are central to future urban development and must be prioritised. Helping decision makers and communities understand the potential opportunities associated with integrated solutions for climate change will encourage urgent and deliberate strides towards adapting cities to the dynamic climate reality.

Editor's note: This article is adapted from the Worldwatch Institute report Renewable Revolution: Low-Carbon Energy by 2030 (www.worldwatch.org/node/6340). Janet Sawin is a World-watch senior fellow and coordinating lead author of [...]

Economic modelling of the global carbon cost of harvesting wood from forests shows a much higher annual cost than that estimated by other models, highlighting a major opportunity for reducing emissions by limiting wood harvests.

‘We have kicked the can down the road once again – but we are running out of road.’ – Rachel Kyte, Dean of Fletcher School at Tufts University.We, in our capacities as scientists, economists, governance and policy specialists, are shifting from warnings to guidance for action before there is no more ‘road.’ The science is clear and irrefutable; humanity is in advanced ecological overshoot. Our overexploitation of resources exceeds ecosystems’ capacity to provide them or to absorb our waste. Society has failed to meet clearly stated goals of the UN Framework Convention on Climate Change. Civilization faces an epochal crossroads, but with potentially much better, wiser outcomes if we act now.What are the concrete and transformative actions by which we can turn away from the abyss? In this paper we forcefully recommend priority actions and resource allocation to avert the worst of the climate and nature emergencies, two of the most pressing symptoms of overshoot, and lead society into a future of greater wellbeing and wisdom. Humanity has begun the social, economic, political and technological initiatives needed for this transformation. Now, massive upscaling and acceleration of these actions and collaborations are essential before irreversible tipping points are crossed in the coming decade. We still can overcome significant societal, political and economic barriers of our own making.Previously, we identified six core areas for urgent global action – energy, pollutants, nature, food systems, population stabilization and economic goals. Here we identify an indicative, systemic and time-limited framework for priority actions for policy, planning and management at multiple scales from household to global. We broadly follow the ‘Reduce-Remove-Repair’ approach to rapid action. To guide decision makers, planners, managers, and budgeters, we cite some of the many experiments, mechanisms and resources in order to facilitate rapid global adoption of effective solutions.Our biggest challenges are not technical, but social, economic, political and behavioral. To have hope of success, we must accelerate collaborative actions across scales, in different cultures and governance systems, while maintaining adequate social, economic and political stability. Effective and timely actions are still achievable on many, though not all fronts. Such change will mean the difference for billions of children and adults, hundreds of thousands of species, health of many ecosystems, and will determine our common future.

We have developed a home energy conservation exercise that illustrates the ways in which heat energy is lost from a home and ultimately, how it can be conserved. Students are asked to calculate the heat loss from a model home before and after applying energy conserving modifications. The difference in these calculations represents the amount of heat energy that could be conserved by making the modifications. To calculate total heat loss for each version of the home, students must account for convection, (heat transfer via air movement), and conduction, (heat transfer through solid materials). Students are provided with a list of building material costs and a budget of $5,000 and are asked to retrofit the un-insulated home in such a way as to conserve the maximum amount of energy and heating cost per heating month. Introductory geology courses commonly include material on resources, energy, and the environment. Current news topics include discussion of the energy resources in the Artic National Wildlife Refuge and the shortage of natural gas. This exercise takes a practical approach to energy conservation and applies it directly to conservation of a geological resource. When used in conjunction with classroom discussions concerning the detrimental effects of the use of fossil fuels and their limited supply, it is an effective way of demonstrating the concept of conservation as a source of energy and a means to preserve the environment. It is also a practical way to incorporate quantitative reasoning into the classroom.

Environmental Kuznets curve (EKC) analysis links changes in environmental quality to national economic growth. The reduced form models, however, do not provide insight into the underlying processes that generate these changes. We compare EKC models to structural transition models of per capita CO2 emissions and per capita GDP, and find that, for the 16 countries which have undergone such a transition, the initiation of the transition correlates not with income levels but with historic events related to the oil price shocks of the 1970s and the policies that followed them. In contrast to previous EKC studies of CO2 the transition away from positive emissions elasticities for these 16 countries is found to occur as a sudden, discontinuous transition rather than as a gradual change. We also demonstrate that the third order polynomial 'N' dependence of emissions on income is the result of data aggregation. We conclude that neither the 'U'- nor the 'N'-shaped relationship between CO2 emissions and income provide a reliable indication of future behaviour.

We have investigated the global warming potential (GWP) of CFC‐I I, CFC‐12, and their replacements, HCFC‐I23 and HFC‐I34a, based on a life‐cycle methodology for refrigeration. We have extended the definition of the total equivalent warming impact (TEWI), which considers the GWP (direct) and GWP (indirect) warming potential of each chemical compound, by adding the GWP (chemical production), GWP (recycling), and GWP (atmospheric breakdown products) for each chemical. We call the new index “life‐cycle warming impact” (LCWI).We find that the GWP (chemical production) contributes by no more than 1% to LCWI, and that the GWP (indirect) is highly dependent on refrigerator eficiency and the fuel mix of the electricity source used to operate the appliance. The GWP (atmospheric breakdown products) may also have a significant impact on LCWI.

Human activity is altering the composition of the atmosphere in unprecedented ways. Fossil fuel combustion, which currently releases 5.6 billion metric tons of carbon annually, in combination with deforestation, has increased atmospheric concentrations of carbon dioxide 25% above pre-industrial levels. Carbon dioxide and other greenhouse gases trap infrared radiation from the earth altering its thermal balance. While carbon dioxide is anticipated to contribute about one-half of human induced global warming, the world energy sector is responsible for an estimated 57% of future global warming when contributions from additional combustion related pollutants are included. In order to stabilize atmospheric concentrations of carbon dioxide even at current elevated levels, computer models suggest the need to reduce emission rates by approximately 75%. Present patterns of energy use are also contributing to major air pollution problems. An analysis of policy options shows that a combination of vastly improved energy efficiency strategies and carbon free energy production technologies are essential to simultaneously slow the rate of global warming and improve air quality. This paper summarizes current knowledge of the greenhouse effect and its consequences, and examines how photovoltaic electricity can contribute to atmospheric stabilization goals. Some specific examples and strategies will be given that may accelerate the rate at which photovoltaic technologies can penetrate the market. Should these strategies succeed, it will have majot implications for materials science including increased attention to pollution problems associated with the manufacture of many promising photovoltaic technologies.