• Energy Research
• 11. Sustainability close
• 7. Clean energy close
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Long-duration gamma-ray bursts (GRBs) release copious amounts of energy across the entire electromagnetic spectrum, and so provide a window into the process of black hole formation from the collapse of massive stars. Previous early optical observations of even the most exceptional GRBs (990123 and 030329) lacked both the temporal resolution to probe the optical flash in detail and the accuracy needed to trace the transition from the prompt emission within the outflow to external shocks caused by interaction with the progenitor environment. Here we report observations of the extraordinarily bright prompt optical and gamma-ray emission of GRB 080319B that provide diagnostics within seconds of its formation, followed by broadband observations of the afterglow decay that continued for weeks. We show that the prompt emission stems from a single physical region, implying an extremely relativistic outflow that propagates within the narrow inner core of a two-component jet.

Hot carrier solar cells overcome the fundamental limitations of conventional devices where charge carriers are photogenerated over a broad energy spectrum but rapidly lose energy to the lattice and are extracted at the lowest energy of the system. In a hot carrier photovoltaic cell, carriers are extracted at higher energies than the absorption threshold, and extraction proceeds sufficiently quickly to avoid dissipative energy loss. We demonstrate a new hot carrier photovoltaic device where a broad spectrum of light is absorbed in metallic layers tens of nanometers thick. Using a semiconductor quantum well resonant tunnel structure we demonstrate energy selective hot carrier extraction from the metal film and show a unique hot carrier signature in the device IV characteristics. Using a multiple beam experiment, we further prove that these carriers arise from a hot electron population rather than via internal photoemission; a necessary requirement for high efficiency photovoltaic operation.

Climate change and biodiversity loss trigger policies targeting and impacting local communities worldwide. However, research and policy implementation often fail to sufficiently consider community responses and to involve them. We present the results of a collective self-assessment exercise for eight case studies of communications with regard to climate change or biodiversity loss between project teams and local communities. We develop eight indicators of good stakeholder communication, reflecting the scope of Verran’s (2002) concept of postcolonial moments as a communicative utopia. We demonstrate that applying our indicators can enhance communication and enable community responses. However, we discover a divergence between timing, complexity and (introspective) effort. Three cases qualify for postcolonial moments, but scrutinising power relations and genuine knowledge co-production remain rare. While we verify the potency of various instruments for deconstructing science, their sophistication cannot substitute trust building and epistemic/transdisciplinary awareness. Lastly, we consider that reforming inadequate funding policies helps improving the work in and with local communities.

The profitability of uncontrolled logging can be a significant obstacle to sustainable forest management, especially in the tropics. Rice et al. (1997) have argued that not only does traditional selective logging provide higher returns but also incurs less damage to forests than sustainable forest management systems that involve harvesting of many species and the creation of large gaps in the forest canopy to foster regeneration of light-demanding species. They claimed that protected areas were the only viable way to conserve forest ecosystems and proposed that loggers be allowed to log forests selectively once, after which the forests should become parks. Here we respond to the challenge posed by Rice et al. by exhaustively reviewing the evidence regarding the viability and desirability of sustainable forest management in the tropics. Following Rice et al., we use the term conventional timber harvesting to refer to existing practice, which typically pays little attention to maintaining long-term timber supply. Sustainable timber management implies taking steps to ensure forests continue to produce timber in the longer term, while maintaining the full complement of environmental services and non-timber products of the forest. Empirical studies tend to confirm the conclusion of Rice et al. (1997) that although sustainable timber management sometimes provides reasonable rates of return, conventional timber harvesting is generally more profitable. This implies that without additional incentives, one cannot expect companies to adopt sustainable management. The shortsightedness of many loggers, the slow rise in international timber prices, political uncertainty, and tenure insecurity simply reinforce this tendency. However, we reject the claim that sustainable timber management generally damages forests more than conventional logging. Rice et al. base their conclusion largely on the particular case of mahogany extraction in Bolivia, and even there it may not hold. In many cases, sustainable timber management performs better in terms of carbon storage and biodiversity conservation than conventional logging approaches, as well as producing more timber. If new carbon markets emerge, sustainable forest management might compete effectively with conventional timber harvesting. Timber certification systems may also provide a sufficient incentive for sustainable forest management in certain circumstances.

Abstract Energy consumption in the household sector has become an important issue in China's energy consumption and an important unit of China's clean energy transformation. Currently, the potential air pollution, carbon emissions and health risks caused by energy consumption in many areas cannot be ignored, and refined and regionalized index-based research data necessary to support decision making are lacking. Based on household-level survey data collected from Qinghai Province, China, we estimated greenhouse gas (GHG) and air pollutant emissions from spatial perspectives, including household energy consumption in pastoral, agropastoral, and agricultural zones. The findings suggest that the total annual GHG and pollutant emissions per capita in the area was 2296.32 kg per year. The highest amount of pollutants was emitted from the pastoral zones, followed by the agropastoral and agricultural zones. CO2 is the primary GHG emitted by household energy consumption. Dung burning was the cause of the high PM2.5 emissions in the pastoral areas, while the use of coal was the primary cause of GHG and pollutant emissions in the agropastoral and agricultural zones. These findings highlight the need to integrate household energy policies with rural development to enable a complete transition towards cleaner fuels.