A conceptual framework and its application for addressing leakage: the case of avoided deforestation

One of the most challenging technical issues associated with project-based mechanisms is that of leakage. A conceptual framework is proposed for the identification and analysis of leakage potentially generated by a project. The categorization of leakage based on the actors responsible for their manifestation is proposed, which divides sources of leakage into primary and secondary types. It is the actors or agents responsible for the baseline activities that cause primary leakage. Secondary leakage occurs when the project’s outputs create incentives for third parties to increase emissions elsewhere. This distinction, based on the source of leakage, provides a basis for the analysis outlined in the paper. The extent and type of leakage will vary depending on the project typology and design. Using a decision tree approach, the process of identifying potential sources of leakage is demonstrated for the case study of avoided deforestation projects. If the main elements determining a baseline are properly identified and understood, in particular the ‘baseline agents’, a combination of the decision tree approach and apportioning responsibility, can assist in the quantification and monitoring of primary leakage. An analysis at the project design stage can also assist in minimizing the risk of future leakage. Econometric methods may prove more useful in analyzing secondary leakage.     

Imagining difference: the experiences of 'transnational' Indian IT professionals in Germany

In this paper we explore the motivations to migrate and the migration experiences of 22 Indian IT professionals in Germany. When studying skilled migration, Germany is an interesting case as it struggled with waves of extreme right activities whilst trying to attract IT professionals from outside the European Union at the same time. In this context, we are interested in the conflicts that the migrants may experience as a result of their desire or obligation to move, their specific cultural baggage and the way in which they encounter the different sides of German society.     

Magnitude and variation in the contribution of bank erosion to the suspended sediment load of the River Severn,UK

The wide range of studies describing the role of bank erosion in fluvial sediment supply have mostly lumped amounts of bank erosion into coarse temporal units, such as years. This paper investigates sediment yields from individual bank erosion events within the upper River Severn, UK (basin area 380 km²). Manual erosion pins and photo-electronic erosion pins were used to estimate bank erosion, and turbidity meters were used to determine suspended sediment transport. At the annual time-scale, the silt-clay fraction of bank-derived sediment accounted for an equivalent of 17 per cent of the suspended load, increasing to an average of 38 per cent at the monthly timescale, and then to an average of 64 per cent at the event timescale. This research highlighted that for an upland catchment, bank erosion was an important supply of suspended sediment, and that for some flood events bank erosion can supply more sediment than is transported. © 1997 John Wiley & Sons, Ltd.     

Modeling the early evolution of Vesta

The early evolution of the asteroid Vesta has been extensively studied because of the availability of relevant data, especially important new studies of HED meteorites which originated from Vesta and the Dawn mission to Vesta in 2011–2012. These studies have concluded that an early melting episode led to the differentiation of Vesta into crust, mantle, and core. This melting episode is attributed to the decay of ²⁶Al, which has a half‐life of 7.17 × 10⁵ yr. This heating produced a global magma ocean. Surface cooling of this magma ocean will produce a solid crust. In this paper, we propose a convective heat‐transfer mechanism that effectively cools the asteroid when the degree of melting reaches about 50%. We propose that a cool solid surface crust, which is gravitationally unstable, will founder into the solid–liquid mix beneath and will very effectively transfer heat that prevents further melting of the interior. In this paper, we quantify this process. If Vesta had a very early formation, melting would commence at an age of about 1,30,000 yr, and solidification would occur at an age of about 10 Myr. If Vesta formed with a time delay greater than about 2 Myr, no melting would have occurred. An important result of our model is that the early melting episode is restricted to the first 10 Myr. This result is in good agreement with the radiometric ages of the HED meteorites.     

The daily‐scale entrance dynamics of intermittently open/closed estuaries

Intermittently open/closed estuaries (IOCE) are a dynamic form of estuary characterised by periodic entrance closure to the ocean. Entrance closure is a function of the relative balance between on and offshore sediment transport with closures occurring during periods of low fluvial discharge whereby the estuary ebb‐tidal prism is reduced. Although the broad scale processes of entrance closure are becoming better understood, there remains limited knowledge on channel morphodynamics during an individual closure event. In this study, the entrance dynamics of three IOCE on the coast of Victoria, Australia, were monitored over a daily timescale following both artificial and natural openings. The influence of changing marine and fluvial conditions on the relative sedimentation rate within the entrance channel was examined. IOCE in Victoria showed two distinct modes of entrance closure: (a) lateral accretion, whereby the estuary gradually closes by longshore drift‐driven spit growth during low river flows; and (b) vertical accretion, where the channel rapidly aggrades under high (> 2 m), near‐normal waves. During storms, when fluvial discharge and wave heights simultaneously increase, large swells will not always close the mouth due to an increase in the ebb‐tidal prism. The estuary water depth and the maximum channel dimensions following opening were not proportional to the opening duration, with this being a function of the wave and fluvial conditions occurring following lagoon drainage. Based on the findings of this work, implementing a successful artificial entrance opening is dependent on reduced onshore sedimentation rates which occur when wave energy is low (< 2 m Hs) relative to river flow. Copyright © 2017 John Wiley & Sons, Ltd.     

Soil water movement and nutrient cycling in semi-arid rangeland: vegetation change and system resilience

Recent decades have seen rapid intensification of cattle production in semi-arid savannah ecosystems, increasingly on formalized ranch blocks. As a result, vegetation community changes have occurred, notably bush encroachment (increased bush dominance) in intensively grazed areas. The exact causes of this vegetation change remain widely debated. Previous studies have suggested: (i) increased leaching of water and nutrients into the subsoil in intensively grazed areas provides deeper rooting bush species with a competitive advantage for soil water and nutrients, and (ii) nutrient leaching may be exacerbated by nutrient inputs from cattle dung and urine. Our research in the Eastern Kalahari showed that in infertile sandy soils both the magnitude of soil water and concentration of soil nutrients leached into the subsoil is largely unaffected by the ecological and biochemical effects of increased cattle use. We found that despite the high soil hydraulic conductivity ( &greaterno;12 cm h⁻¹), relatively high subsoil moisture contents and the restriction of water movement to matrix flow pathways prevent leaching losses beyond the rooting zone of savannah grass species. No significant differences in patterns of soil water redistribution were noted between bush dominant and grass dominant sites. We also found that the low nutrient status of Kalahari soils and leachate movement as matrix flow combine to allow nutrient adsorption on to soil particles. Nutrient adsorption ensures that nitrogen and phosphorus cycling remains topsoil dominated even following the removal of vegetation and direct nutrient inputs in cattle dung and urine. This conclusion refutes environmental change models that portray increases in the leaching of soil water and available nitrogen as a major factor causing bush encroachment. This provides a possible explanation for the now widely cited, but hitherto unexplained, resilience of dryland soils. We suggest that infertile sandy soils appear resilient to changes in soil water distribution and nutrient availability caused by increased cattle use. Hence, soil characteristics contribute to the resilience to permanent ecological change that is increasingly recognized as an attribute of semi-arid rangelands. © 1998 John Wiley & Sons, Ltd.     

The deglaciation of the western sector of the Irish Ice Sheet from the inner continental shelf to its terrestrial margin

This paper provides a new deglacial chronology for retreat of the Irish Ice Sheet from the continental shelf of western Ireland to the adjoining coastline, a region where the timing and drivers of ice recession have never been fully constrained. Previous work suggests maximum ice-sheet extent on the outer western continental shelf occurred at ~26–24 cal. ka BP with the initial retreat of the ice marked by the production of grounding-zone wedges between 23–21.1 cal. ka BP. However, the timing and rate of ice-sheet retreat from the inner continental shelf to the present coast are largely unknown. This paper reports 31 new terrestrial cosmogenic nuclide (TCN) ages from erratics and ice-moulded bedrock and three new optically stimulated luminescence (OSL) ages on deglacial outwash. The TCN data constrain deglaciation of the near coast (Aran Islands) to ~19.5–18.5 ka. This infers ice retreated rapidly from the mid-shelf after 21 ka, but the combined effects of bathymetric shallowing and pinning acted to stabilize the ice at the Aran Islands. However, marginal stability was short-lived, with multiple coastal sites along the Connemara/Galway coasts demonstrating ice recession under terrestrial conditions by 18.2–17. ka. This pattern of retreat continued as ice retreated eastward through inner Galway Bay by 16.5 ka. South of Galway, the Kilkee–Kilrush Moraine Complex and Scattery Island moraines point to late stage re-advances of the ice sheet into southern County Clare ~14.1–13.3 ka, but the large errors associated with the OSL ages make correlation with other regional re-advances difficult. It seems more likely that these moraines are the product of regional ice lobes adjusting to internal ice-sheet dynamics during deglaciation in the time window 17–16 ka.     

Simulation of the 2004 tsunami of Les Saintes in Guadeloupe (Lesser Antilles) using new source constraints

Natural Hazards - The arc of the Lesser Antilles is associated with a significant tectonic activity due to the subduction of the Atlantic oceanic plate under the Caribbean plate. Earthquakes in...     

Effects of iron limitation on intracellular cadmium of cultured phytoplankton: Implications for surface dissolved cadmium to phosphate ratios

This study compares intracellular Cd content (Cd:C) of cultured marine phytoplankton grown under various Fe levels, with estimated particulate Cd:P ratios derived from regression slopes of Cd versus PO₄³⁻ relationships from a global dataset. A 66-fold difference in Cd:C ratios was observed among the seven species grown under identical Fe concentrations, with oceanic diatoms having the highest Cd quotas and prymesiophytes the lowest. Interestingly, all species significantly increased their Cd:C ratios under Fe-limitation (on average 2-fold). The global data set also showed that the mean estimated Cd:P ratio of surface water particulates in HNLC (high nutrient low chlorophyll) regions were approximately 2-fold higher than non-HNLC regions. A sequence of events are proposed to explain high Cd:P ratios in HNLC waters. First, the seasonal relief from Fe-limitation in HNLC regions leads to blooms of large chain forming diatoms with high intrinsic Cd:P ratios. These large blooms may, in theory, deplete surface water CO₂ and Zn concentrations, which ultimately, would result in increased Cd uptake. Eventually these blooms will run out of Fe, which has been shown to further increase intercellular Cd via growth biodilution and increased Cd uptake through non-specific Fe(II) transporters. Ultimately, Fe-limited diatoms with enhanced Cd quotas will sink out of surface waters leading to pronounced regional differences in Cd:P ratios between HNLC and non-HNLC waters in the global ocean.