There is a growing recognition that responding to climate change necessitates urban adaptation. We sketch a transdisciplinary research effort, arguing that actionable research on urban adaptation needs to recognize the nature of cities as social networks embedded in physical space. Given the pace, scale and socioeconomic outcomes of urbanization in the Global South, the specificities and history of its cities must be central to the study of how well-known agglomeration effects can facilitate adaptation. The proposed effort calls for the co-creation of knowledge involving scientists and stakeholders, especially those historically excluded from the design and implementation of urban development policies.

The U.S. Department of Energy's Office of Scientific and Technical Information

The cost and efficiency of direct air capture (DAC) of carbon dioxide (CO₂) will be decisive in determining whether this technology can play a large role in decarbonization. To probe the role of meteorological conditions on DAC we examine, at 1 × 1° resolution for the continental United States (U.S.), the impacts of temperature, humidity, atmospheric pressure, and CO₂ concentration for a representative amine-based adsorption process. Spatial and temporal variations in atmospheric pressure and CO₂ concentration lead to strong variations in the CO₂ available in ambient air across the U.S. The specific DAC process that we examine is described by a process model that accounts for both temperature and humidity. A process that assumes the same operating choices at all locations in the continental U.S. shows strong variations in performance, with the most influential variables being the H₂O gas phase volume fraction and temperature, both of which are negatively correlated with DAC productivity for the specific process that we consider. The process also shows a moderate positive correlation of ambient CO₂ with productivity and recovery. We show that optimizing the DAC process at seven representative locations to reflect temporal and spatial variations in ambient conditions significantly improves the process performance and, more importantly, would lead to different choices in the sites for the best performance than models based on a single set of process conditions. Our work provides a framework for assessing spatial variations in DAC performance that could be applied to any DAC process and indicates that these variations will have important implications in optimizing and siting DAC facilities.

Brelsford, C., M. Dumas, E. Schlager, B. J. Dermody, M. Aiuvalasit, M. R. Allen-Dumas, J. Beecher, U. Bhatia, P. D'Odorico, M. Garcia, P. Gober, D. Groenfeldt, S. Lansing, K. Madani, L. Méndez-Barrientos, E. Mondino, M. F. Müller, F. C. O'Donnell, P. M. Owuor, J. Rising, M. R. Sanderson, F. A. A. Souza, and S. C. Zipper. 2020. Developing a sustainability science approach for water systems. Ecology and Society 25(2):23. https://doi.org/10.5751/ES-11515-250223

Bioenergy with carbon capture and storage (BECCS) is one strategy to remove CO₂ from the atmosphere. To assess the potential scale and cost of CO₂ sequestration from BECCS in the US, this analysis models carbon sequestration net of supply chain emissions and costs of biomass production, delivery, power generation, and CO₂ capture and sequestration in saline formations. The analysis includes two biomass supply scenarios (near-term and long-term), two biomass logistics scenarios (conventional and pelletized), and two generation technologies (pulverized combustion and integrated gasification combined cycle). Results show marginal cost per tonne CO₂ (accounting for costs of electricity and CO₂ emissions of reference power generation scenarios) as a function of CO₂ sequestered (simulating capture of up to 90% of total CO₂ sequestration potential) and associated spatial distribution of resources and generation locations for the array of scenario options. Under a near-term scenario using up to 206 million tonnes per year of biomass, up to 181 million tonnes CO₂ can be sequestered annually at scenario-average costs ranging from $62 to $137 per tonne CO₂; under a long-term scenario using up to 740 million tonnes per year of biomass, up to 737 million tonnes CO₂ can be sequestered annually at scenario-average costs ranging from $42 to $92 per tonne CO₂. These estimates of CO₂ sequestration potential may be reduced if future competing demand reduces resource availability or may be increased if displaced emissions from conventional power sources are included. Results suggest there are large-scale opportunities to implement BECCS at moderate cost in the US, particularly in the Midwest, Plains States, and Texas.

Strategies for creating quantitative projections for human systems, especially impervious surfaces, are necessary to consider the human drivers of climate and ecosystem change. There are models that generate predictions of how impervious surfaces may change in response to different potential futures, but few tools exist for validating those predictions. We seek to fill that gap. We demonstrate a statistically robust sublinear scaling relationship between population and urban imperviousness across a 15 year history. We show that Integrated Climate and Land‐Use Scenarios (ICLUS) urbanization projections are also consistent with theory. These results demonstrate a theory that can be used to validate other models' predictions of urban growth and land cover change, analogous to the ways in which allometric scaling laws in biology have been used to validate process‐based models of ecosystem composition under different climate scenarios.