• Energy Research

AbstractGeoengineering has been proposed to stabilize global temperature, but its impacts on crop production and stability are not fully understood. A few case studies suggest that certain crops are likely to benefit from solar dimming geoengineering, yet we show that geoengineering is projected to have detrimental effects for groundnut. Using an ensemble of crop‐climate model simulations, we illustrate that groundnut yields in India undergo a statistically significant decrease of up to 20% as a result of solar dimming geoengineering relative to RCP4.5. It is somewhat reassuring, however, to find that after a sustained period of 50 years of geoengineering crop yields return to the nongeoengineered values within a few years once the intervention is ceased.

AbstractNumerous studies in epidemiology, meteorology, and climate change research have demonstrated a significant association between abnormal ambient temperature and mortality. However, there is a shortage of research attention to a systematic assessment of potential mitigation measures which could effectively reduce the heat-related morbidity and mortality risks. This study first illustrates a conceptualization of a systems analysis version of urban framework for climate service (UFCS). It then constructs a system dynamics (SD) model for the UFCS and employs this model to quantify the impacts of heat waves on public health system in Shanghai and to evaluate the performances of two mitigation measures in the context of a real heat wave event in July 2013 in the city. Simulation results show that in comparison with the baseline without mitigation measures, if the hospital system could prepare 20% of beds available for emergency response to heat waves once receiving the warning in advance, the number of daily deaths could be reduced by 40–60 (15.8–19.5%) on the 2 days of day 7 and day 8; if increasing the minimum living allowance of 790 RMB/month in 2013 by 20%, the number of daily deaths could be reduced by 50–70 (17.7–21.9%) on the 2 days of day 8 and day 12. This tool can help policy makers systematically evaluate adaptation and mitigation options based on performance assessment, thus strengthening urban resilience to changing climate.

Brazil plays a major role in the global biofuel economy as the world’s second largest producer and consumer and the largest exporter of ethanol. Its demand is expected to significantly increase in coming years, largely driven by national and international carbon mitigation targets. However, biofuel crops require significant amounts of water and land resources that could otherwise be used for the production of food, urban water supply, or energy generation. Given Brazil’s uneven spatial distribution of water resources among regions, a potential expansion of ethanol production will need to take into account regional or local water availability, as an increased water demand for irrigation would put further pressure on already water-scarce regions and compete with other users. By applying an environmentally extended multiregional input-output (MRIO) approach, we uncover the scarce water footprint and the interregional virtual water flows associated with sugarcane-derived biofuel production driven by domestic final consumption and international exports in 27 states in Brazil. Our results show that bio-ethanol is responsible for about one third of the total sugarcane water footprint besides sugar and other processed food production. We found that richer states such as São Paulo benefit by accruing a higher share of economic value added from exporting ethanol as part of global value chains while increasing water stress in poorer states through interregional trade. We also found that, in comparison with other crops, sugarcane has a comparative advantage when rainfed while showing a comparative disadvantage as an irrigated crop; a tradeoff to be considered when planning irrigation infrastructure and bioethanol production expansion.

China has experienced rapid urbanization in the last three decades, with more than half of the population living in cities since 2012. The extent of urban production and urban lifestyles has become one of the main drivers for China's CO2 emissions. To analyze drivers of CO2 emissions we use a consumption-based accounting approach that allocates all emissions along the production chain to the product and place of final consumption, whereas a production-based approach would allocate all emissions to the place of origin. In this study, we focus on the spatial distribution of production activities leading to CO2 emissions across China as a consequence of final consumption in four Chinese mega cities: Beijing, Shanghai, Tianjin, and Chongqing. Urban consumption not only causes a large amount of emissions within its territory, but also imposes even much more emissions to its surrounding provinces via interregional supply chains. Results show that more than 48% of CO2 emissions related to goods consumed in Chongqing and more than 70% for Beijing, Shanghai and Tianjin occurred outside of the respective city boundary. In addition to the usual focus on efficiency, our analysis adds insights into the causes of CO2 emissions by looking at the drivers and types of consumption. Addressing consumption patterns in China's cities is critical for China's low carbon development.

This paper proposes an index-based assessment tool to consolidate diverse opinions of various stakeholders on their assessments of sector-specific risks posed by climate change, and to aggregate these opinions into intuitive and comparable graphs. This tool enables cities to measure and monitor the multiple factors that contribute to their resilience towards climate risk and hazard in the long term. We applied this tool to five key infrastructure sectors in six representative cities in the Yangtze River Delta region. The graphs generated provide for the first time first-hand insights into the aggregative understanding of various stakeholders with regard to the current and future climate risk in their concerned sectors and cities. Our results indicate that a high level of exposure is not automatically associated with a high level of vulnerability across our selected cities. While all cities need to make efforts to reduce their vulnerability towards climate hazards, those characterized by “lower level of exposure but higher level of vulnerability” need to make more urgent and much greater efforts.

Abstract China, like many other countries, is promoting the development of liquid biofuel, including bioethanol and biodiesel. The Chinese government has set biofuel development targets for the coming decade and sanctioned a series of supportive policies. This paper provides a comprehensive overview of current liquid biofuel development in China, related government policies, and the potential opportunities and challenges for its future expansion. Our assessment is based on two rounds of in-depth fieldwork and a thorough literature review. The assessment shows that the prevailing concern on food security has pushed China to move from cereal-based to non-cereal-based biofuel production. Emphasis has also been put on utilizing new marginal land for feedstock production. Our assessment indicates that the targets of China's biofuel development are cautious and feasible, but on the other hand there are still severe challenges for the sustainability of such development. A better understanding of China's experience in striking a balance between energy security, food security and environmental protection would inform the debates across country boundaries and contribute to the efforts for global sustainability.