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To mitigate climate change, individual greenhouse gas emissions need to decline substantially. This paper empirically explores the relationship between individual carbon footprints and carbon literacy as well as socio-economic and attitudinal factors. To operationalize carbon literacy, we distinguish between carbon knowledge and carbon engagement. Our econometric analysis uses widely representative survey data for 1000 individuals in Germany and distinguishes between components of an aggregate carbon footprint and of carbon footprints related with electricity consumption, heating, motorized individual transport, aviation, and dietary choices. We find a negative and sizeable correlation between carbon engagement and the aggregate footprint, as well as the footprints related to electricity consumption and diet. For example, a one-unit increase in our index reflecting carbon engagement corresponds to a decrease in the aggregate carbon footprint of about 4%. Furthermore, for carbon knowledge we find a negative correlation with the carbon footprint from diet. We also find significant correlations between the carbon footprints and gender, age, income, education, environmental preferences, and policy orientation, which generally exhibit the intuitively expected signs, but differ somewhat across activities. Overall, our findings support the notion that fostering carbon engagement represents a more effective strategy for reducing individuals' carbon footprints than enhancing carbon knowledge.

AbstractSemi‐natural mountain grasslands are increasingly exposed to environmental stress under climate change. However, which are the environmental factors that limit plants in these grasslands? Also, is the present management effective against these changes? Fitness‐related functional traits may offer a way to detect changes in performance and provide new insights into their vulnerability to climate change. We investigated changes in performance and variability of functional traits of the mountain grassland target species Arnica montana along a climate gradient in Central German low mountain ranges. This gradient represents at its lower end climate conditions that are expected at its upper end under future climate change. We measured vegetative, generative, and physiological traits to account for multiple ways of plant responses to the environment. Using mixed effects and multivariate models, we evaluated changes in trait values among individuals as well as the variability of their populations in order to assess performance under changing summer aridity and different management regimes. Fitness‐related performance of most traits showed strongly positive associations with reduced summer aridity at higher elevations, while only specific leaf area and leaf dry matter content showed no association. This suggests a higher performance level at less arid montane sites and that the physiological traits are less sensitive to this climate change factor. The coefficient of variation of almost all traits declined steadily with decreasing site aridity. We suggest that this reduced variability indicates a lower environmental stress level for A. montana toward its environmental optimum at montane elevations, especially because the trait performance increased simultaneously. Surprisingly, management factors and habitat characteristics had only low influence on both trait performance and variability. In summary, summer aridity had a stronger effect to shape the trait performance and variability of A. montana under increased environmental stress than management and other habitat characteristics.

Abstract The performance of a multi-level overtopping wave energy converter has been numerically investigated in a three-dimensional wave tank. The device has three extra slots and is positioned on a breakwater. The span length of the breakwater is the main parameter associated with the three-dimensional effects on the hydraulic efficiency of the wave energy device. It has been shown that the device with a finite span yields a lower captured crest energy due to waves falling-down the edges during the run-up process. The result also implies that as the span of the device is increased, the efficiency tends to increase further to resemble the two-dimensional device. The three-dimensional mechanism has a significant influence on the potential energy in the water being stored by the higher reservoirs, while that of lower ones have relatively smaller effects. In addition, a relation between hydraulic efficiencies of two and three-dimensional devices has been proposed.

In 2021, 56% of the global population lived in cities, and by 2050 the ratio of urban-to-rural population is expected to reach 67% [...]

This work focused on the conversion of crude palm kernel oil (CPKO) to biojet fuel via deoxygenation reaction in a fixed bed reactor. The catalyst was Pt supported on activated carbon (Pt/C). The investigation involved the effects of various operating parameters such as reaction temperature (350–420 °C), pressure (250 and 500 psi), flow rate of CPKO (0.02 and 0.04 mL/min), flow rate of hydrogen (17.5, 35.0, and 70.0 mL/min), and the amount of catalyst (0.05 and 0.07 g) on the reaction performance and the fuel properties of product. The biojet yield of 58.29%, with the major content of linear alkane in the range of jet fuel (nC8-nC16) of 27.68% and the productivity of 9.32 g product/g catalyst·h were achieved at the optimal operating conditions (420 °C, 500 psi, CPKO flow rate at 0.02 mL/min, hydrogen flow rate at 17.50 mL/min (H2-to-CPKO molar ratio of 28.02), and 0.07 g of Pt/C catalyst). The oxygen content was reduced from 18.83% (in CPKO) to 14.96% (in the product). To improve the freezing point of biojet fuel via cracking and aromatization, the catalyst bed was modified by adding HZSM-5 as a catalyst bed adjacent to the bed of Pt/C. The freezing point of product was significantly lowered by 30 °C.

Due to its purchasing power, the public food service sector is viewed as a potential transformative driver towards sustainable food systems. Organic meal planning and regional procurement may be a vital implementation strategy towards Planetary Health Diets in the communal catering arena. Capable of unleashing desirable synergies within local foodsheds, this transition pathway can potentially benefit all stages of the value chain, while also positively influencing consumer dietary behavior. Transformation, however, poses complex challenges to caterers, as it demands a shift in mindset regarding the philosophy, organization, and management of cafeteria systems as well as the need for affordable and aggregated supplies of source-identified local organic foods. This action research case study engaged the public caterer of a German University, undergraduate students, and additional stakeholders in a Living Lab to develop a weekly farm-to-table cafeteria menu, including its actual preparation, based on a conceptual sustainability standard. Hence, through an iterative process, involving two feedback cycles, an ambitious set of nutritional and procurement criteria were devised, inspired by the external input from exemplary practitioners in the field of green cuisine and procurement. The resulting meal plan was then subjected to an evaluation vis-á-vis its compliance with (1) dietary recommendations, (2) seasonality, (3) organic certification, (4) a defined foodshed boundary, (5) budget neutrality, and (6) life cycle assessment.

Global-scale hydrological models are routinely used to assess water scarcity, flood hazards and droughts worldwide. Recent efforts to incorporate anthropogenic activities in these models have enabled more realistic comparisons with observations. Here we evaluate simulations from an ensemble of six models participating in the second phase of the Inter-Sectoral Impact Model Inter-comparison Project (ISIMIP2a). We simulate monthly runoff in 40 catchments, spatially distributed across eight global hydrobelts. The performance of each model and the ensemble mean is examined with respect to their ability to replicate observed mean and extreme runoff under human-influenced conditions. Application of a novel integrated evaluation metric to quantify the models' ability to simulate timeseries of monthly runoff suggests that the models generally perform better in the wetter equatorial and northern hydrobelts than in drier southern hydrobelts. When model outputs are temporally aggregated to assess mean annual and extreme runoff, the models perform better. Nevertheless, we find a general trend in the majority of models towards the overestimation of mean annual runoff and all indicators of upper and lower extreme runoff. The models struggle to capture the timing of the seasonal cycle, particularly in northern hydrobelts, while in southern hydrobelts the models struggle to reproduce the magnitude of the seasonal cycle. It is noteworthy that over all hydrological indicators, the ensemble mean fails to perform better than any individual model—a finding that challenges the commonly held perception that model ensemble estimates deliver superior performance over individual models. The study highlights the need for continued model development and improvement. It also suggests that caution should be taken when summarising the simulations from a model ensemble based upon its mean output. Environmental Research Letters, 13 (6) ISSN:1748-9326 ISSN:1748-9318