Moving academic conferences online: Aids and barriers to delegate participation

In‐person academic conferences are important to disseminate research and provide networking opportunities. Whether academics attend in‐person conferences is based on the cost, accessibility, and safety of the event. Therefore, in‐person conferences are less accessible to academics and stakeholders that are unable to overcome some of these factors, which then act as a barrier to equal and inclusive participation. Additionally, the carbon footprint of conference travel is increasingly becoming a factor in deciding on whether to attend a conference. Online conferences may provide opportunities to mitigate these challenges. Here, we illustrate how a learned society can move their conference online. Then, comparing data acquired from the virtual conference and previous in‐person conferences, we explore the aids and barriers influencing the decision of delegates to attend the meetings. Ultimately, moving meetings online aids delegate participation by removing concerns about travel, cost, and carbon emissions, but there remains a barrier to participation as online meetings are perceived as less effective for networking and social opportunities.     

A plant‐specific model approach to assess effects of repowering measures on existing biogas plants: The case of Baden‐Wuerttemberg

Up to the latest versions of the German renewable energy act (EEG), there had been a constant growth of new biogas plants (BGPs). After reaching a stagnation in the last years, today the focus has shifted to improving the existing BGPs. Assuming that most plants have not reached the technical end of life, the question arises on how an operation can be realized beyond the initial EEG support period of 20 years. In addition, new legal and economic conditions require the implementation of adjustments, that is, “repowering measures.” Based on a method review, a plant‐specific model approach is presented to assess repowering measures for a wide range of BGPs differing in capacity, substrate mixture and agricultural structures. The techno‐economic model includes different performance indicators like levelized cost of electricity (LCOE) and temporal aspects like technical progress. Using a data set for BGPs in the state of Baden‐Wuerttemberg (Germany), results are illustrated for the different model modules and three repowering scenarios of an extended operation period of ten years. The scenarios regard different options to meet the requirements of the current EEG, namely the flexibilization and restrictions on energy crops, in comparison with a reference case. While in repowering scenarios, the number of plants decreases between 54% and 69% and the overall power capacity changes between ?48% and 13% until 2035. The results further show a reduction potential in the specific area demand and GHG emission up to 12% and 24%, respectively. Technical progress, additional revenues and capacity premiums are shown to be an important factor for efficient substrate utilization, low LCOE and thereby the enabling of an extended operation period. The scenario results indicate that the agricultural areas for energy crop cultivation and the amount of manure used in BGPs will be reduced considerably, inducing new chances and challenges in the future.     

Otoacoustic emissions from insect ears having just one auditory neuron

Sensitive hearing organs often employ nonlinear mechanical sound processing which produces distortion-product otoacoustic emissions. Such emissions are also recorded from insect tympanal organs. Here we report high frequency distortion-product emissions, evoked by stimulus frequencies up to 95 kHz, from the tympanal organ of a notodontid moth, Ptilodon cucullina, which contains only a single auditory receptor neuron. The 2f1–f2 distortion-product emission reaches sound levels above 40 dB SPL. Most emission growth functions show a prominent notch of 20 dB depth (n = 20 trials), accompanied by an average phase shift of 119°, at stimulus levels between 60 and 70 dB SPL, which separates a low- and a high-level component. The emissions are vulnerable to topical application of ethyl ether which shifts growth functions by about 20 dB towards higher stimulus levels. For the mammalian cochlea, Lukashkin and colleagues have proposed that distinct level-dependent components of nonlinear amplification do not necessarily require interaction of several cellular sources but could be due to a single nonlinear source. In notodontids, such a physiologically vulnerable source could be the single receptor cell. Potential contributions from accessory cells to the nonlinear properties of the scolopidial hearing organ are still unclear.     

Sectoral Aggregation Error in the Accounting of Energy and Emissions Embodied in Trade and Consumption

Correctly accounting for the energy and emissions embodied in consumption and trade is essential to effective climate policy design. Robust methods are needed for both policy making and research—for example, the assignment of border carbon adjustments (BCAs) and greenhouse gas emission reduction responsibilities rely on the consistency and accuracy of such estimates. This analysis investigates the potential magnitude and consequences of the error present in estimates of energy and emissions embodied in trade and consumption. To quantify the error of embodied emissions accounting, we compare the results from the disaggregated Global Trade Analysis Project (GTAP 8) data set, which contains 57 sectors to results from different levels of aggregation of this data set (3, 7, 16, and 26 sectors), using 5,000 randomly generated sectoral aggregation schemes as well as aggregations generated using several commonly applied decisions rules. We find that some commonly applied decision rules for sectoral aggregation can produce a large error. We further show that an aggregation scheme that clusters sectors according to their energy, emissions, and trade intensities (net exports over output) can minimize error in embodied energy and emissions accounting at different levels of aggregation. This sectoral aggregation scheme can be readily used in any input‐output analysis and provide useful information for computable general equilibrium modeling exercises in which sector aggregation is necessary, although our findings suggest that, when possible, the most disaggregated data available should be used.     

Reducing CO<Subscript>2</Subscript> Emissions from Domestic Travel: Exploring the Social and Health Impacts

The importance and meaning of social and recreational travel for a diverse group of Auckland residents is explored in this article. Study participants identified a range of social and health benefits, including maintaining social connections with family and friends, opportunities to participate in physical activity, and reducing stress. However, many of these trips are by car. New Zealand has one of the highest rates of private car ownership internationally, low-density urban development, and a poor public transport infrastructure. Social and recreational trips make up a sizeable proportion of domestic travel and are contributing to New Zealand’s increasing rate of CO₂ emissions. There is an obvious need to address the negative ecological impacts of human activity. Our findings suggest that alongside strategies to reduce CO₂ emissions, it also is important to introduce measures to maintain the benefits from social and recreational travel. Suggestions are made for further areas of research.     

Product specific emissions from municipal solid waste landfills

For the inventory analysis of environmental impacts associated with products in Life Cycle Assessment (LCA) there is a great need for estimates of emissions from waste products disposed at municipal solid waste landfills (product specific emissions). Since product specific emissions can not be calculated or measured directly at the landfills, they must be estimated by modeling of landfill processes. This paper presents a landfill model based on a large number of assumptions and approximations concerning landfill properties, waste product properties and characteristics of various kinds of environmental protection systems (e.g. landfill gas combustion units and leachate treatment units). The model is useful for estimation of emissions from waste products disposed in landfills and it has been made operational in the computer tool LCA-LAND presented in a following paper. In the model, waste products are subdivided into five groups of components: general organic matter (e.g. paper), specific organic compounds (e.g. organic solvents), inert components (e.g. PVC), metals (e.g. cadmium), and inorganic non-metals (e.g. chlorine,) which are considered individually. The assumptions and approximations used in the model are to the extent possible scientifically based, but where scientific information has been missing, qualified estimates have been made to fulfill the aim of a complete tool for estimation of emissions. Due to several rough simplifications and missing links in our present understanding of landfills, the uncertainty associated with the model is relatively high.     

The potential of Miscanthus to sequester carbon in soils: comparing field measurements in Carlow,Ireland to model predictions

Growing bioenergy crops such as Miscanthus has the potential to mitigate atmospheric carbon dioxide emissions by the replacement of fossil fuels and by storing carbon (C) in the soil due to land use change. Here we compare direct measurements of soil organic C fractions made in Carlow (Ireland) to model predictions made by RothC and a cohort model. Our results show that when Miscanthus is grown on land previously under arable agriculture, the soil organic C will increase to a level above that of native pasture, as Miscanthus organic material is shown to have a slow decomposition rate. In addition we demonstrate that for measured organic C, fractions of different lability are similar to the C pools used in RothC. Using the model predictions from RothC and Miscanthus yields from MISCANFOR, we predict that in Ireland, changing the land use from arable to Miscanthus plantations has the potential to store between 2 and 3 Mg C ha^?1 y^?1 depending on the crop yield and the initial soil organic C level.     

Evolutionary adaptations of cochlear function in Jamaican mormoopid bats

Mormoopid bat species have their echolocation system adapted to different hunting strategies. To study the corresponding mechanical properties of their inner ear, we measured distortion-product otoacoustic emissions to assess cochlear sensitivity and tuning. Mormoops blainvillii, Pteronotus macleayii and P. quadridens use frequency-modulated echolocation signals, sometimes preceded by a short narrowband signal component. Their distortion-product otoacoustic emission-threshold curves are most sensitive between 30 and 50 kHz and show no adaptation to the narrowband echolocation components. In contrast, the constant-frequency bat P. parnellii always uses long constant-frequency call components. Its inner ear is maximally sensitive at 62 kHz, the echo-frequency of the dominant constant-frequency component, and pronounced insensitivities at 61 and 93 kHz (CF2 and CF3 call frequency) are the major evolutionary change in comparison to its relatives. Furthermore, in P. parnellii, the optimum cochlear frequency separation is minimal at 62 and 93 kHz, associated with enhanced cochlear tuning, while for the other mormoopids there is no indication of enhanced tuning. The phylogeny of mormoopids, assessed by mitochondrial DNA analysis, shows a close relationship between the Pteronotus species. This suggests that major cochlear redesign, associated with the acquisition of echolocation-call specific cochlear processing in P. parnellii, has occurred within a relatively short evolutionary time scale. Accepted: 30 April 1999     

Global relative species loss due to first‐generation biofuel production for the transport sector

The global demand for biofuels in the transport sector may lead to significant biodiversity impacts via multiple human pressures. Biodiversity assessments of biofuels, however, seldom simultaneously address several impact pathways, which can lead to biased comparisons with fossil fuels. The goal of the present study was to quantify the direct influence of habitat loss, water consumption and greenhouse gas (GHG) emissions on potential global species richness loss due to the current production of first‐generation biodiesel from soybean and rapeseed and bioethanol from sugarcane and corn. We found that the global relative species loss due to biofuel production exceeded that of fossil petrol and diesel production in more than 90% of the locations considered. Habitat loss was the dominating stressor with Chinese corn, Brazilian soybean and Brazilian sugarcane having a particularly large biodiversity impact. Spatial variation within countries was high, with 90th percentiles differing by a factor of 9 to 22 between locations. We conclude that displacing fossil fuels with first‐generation biofuels will likely negatively affect global biodiversity, no matter which feedstock is used or where it is produced. Environmental policy may therefore focus on the introduction of other renewable options in the transport sector.     

Net land‐atmosphere flows of biogenic carbon related to bioenergy: towards an understanding of systemic feedbacks

The notion that biomass combustion is carbon neutral vis‐a‐vis the atmosphere because carbon released during biomass combustion is absorbed during plant regrowth is inherent in the greenhouse gas accounting rules in many regulations and conventions. But this ‘carbon neutrality’ assumption of bioenergy is an oversimplification that can result in major flaws in emission accounting; it may even result in policies that increase, instead of reduce, overall greenhouse gas emissions. This commentary discusses the systemic feedbacks and ecosystem succession/land‐use history issues ignored by the carbon neutrality assumption. Based on recent literature, three cases are elaborated which show that the C balance of bioenergy may range from highly beneficial to strongly detrimental, depending on the plants grown, the land used (including its land‐use history) as well as the fossil energy replaced. The article concludes by proposing the concept of GHG cost curves of bioenergy as a means for optimizing the climate benefits of bioenergy policies.