This study reviewed first available frameworks for climate change adaptation in the public health arena. The authors propose a conceptual framework with a three‐step procedure to assess climate change vulnerabilities.   First, the study team identified and modeled heat stress, environmental, social, and health factors that are closely related to climate change and vulnerability. Second, the team quantified the cumulative impacts of four high‐priority factors at regional level using the cumulative environmental hazard inequality index. Third, the team applied the environmental justice screening tool to map the four high‐priority factors to identify areas with increased vulnerability to the health impacts of climate change. In addition to the heat stress estimated using air monitoring data, the team applied satellite data to create models of the land surface temperature at 30‐meter resolution and provided a measure of small‐scale variations in the urban heat island. Regionally, based on the cumulative environmental hazard inequality index, adaptive capacity had the greatest cumulative inequality in both the San Francisco Bay Area and Fresno regions, and those inequalities were largely contributed by inequalities from tree canopy shading. Social and health vulnerability had the second largest cumulative inequality in both regions. Lack of car ownership was the major impact in creating such inequalities. Air pollution inequality came third, based on the main pollutants in both regions, and this was mainly contributed by inequalities from diesel particulate matter exposure. By contrast, cumulative inequalities in heat stress were the least. However, heat stress inequality was still significant different from the equality line. Locally, based on the environmental justice screening tool, downtown urban areas for both Fresno County and the San Francisco Bay Area showed cumulatively higher vulnerability than more outlying areas, with the exception of the rural western portion of Fresno County. The cumulative inequalities calculated by the cumulative environmental hazard inequality index and the environmental justice screening method can be a useful tool for highlighting areas of greatest vulnerability for targeting adaptation planning.

Permafrost and methane hydrates are large, climate-sensitive old carbon reservoirs that have the potential to emit large quantities of methane, a potent greenhouse gas, as the Earth continues to warm. We present ice core isotopic measurements of methane (Δ14C, δ13C, and δD) from the last deglaciation, which is a partial analog for modern warming. Our results show that methane emissions from old carbon reservoirs in response to deglacial warming were small (<19 teragrams of methane per year, 95% confidence interval) and argue against similar methane emissions in response to future warming. Our results also indicate that methane emissions from biomass burning in the pre-Industrial Holocene were 22 to 56 teragrams of methane per year (95% confidence interval), which is comparable to today.

Human-driven environmental changes shape ecological communities from local to global scales. Within cities, landscape-scale patterns and processes and species characteristics generally drive local-scale wildlife diversity. However, cities differ in their structure, species pools, geographies and histories, calling into question the extent to which these drivers of wildlife diversity are predictive at continental scales. In partnership with the Urban Wildlife Information Network, we used occurrence data from 725 sites located across 20 North American cities and a multi-city, multi-species occupancy modelling approach to evaluate the effects of ecoregional characteristics and mammal species traits on the urbanization-diversity relationship. Among 37 native terrestrial mammal species, regional environmental characteristics and species traits influenced within-city effects of urbanization on species occupancy and community composition. Species occupancy and diversity were most negatively related to urbanization in the warmer, less vegetated cities. Additionally, larger-bodied species were most negatively impacted by urbanization across North America. Our results suggest that shifting climate conditions could worsen the effects of urbanization on native wildlife communities, such that conservation strategies should seek to mitigate the combined effects of a warming and urbanizing world.