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21.
ABSTRACT

Changes in agricultural practices can play a pivotal role in climate change mitigation by reducing the need for land use change as one of the biggest sources of GHG emissions, and by enabling carbon sequestration in farmers’ fields. Expansion of smallholder and commercial agriculture is often one of the main driving forces behind deforestation and forest degradation. However, mitigation programmes such as REDD+ are geared towards conservation efforts in the forestry sector without prominently taking into account smallholder agricultural interests in project design and implementation. REDD+ projects often build on existing re- and afforestation projects without major changes in their principles, interests and assumptions. Informed by case study research and interviews with national and international experts, we illustrate with examples from Ethiopia and Indonesia how REDD+ projects are implemented, how they fail to adequately incorporate the demands of smallholder farmers and how this leads to a loss of livelihoods and diminishing interest in participating in REDD+ by local farming communities. The study shows how the conservation-based benefits and insecure funding base in REDD+ projects do not compensate for the contraction in livelihoods from agriculture. Combined with exclusive benefit-sharing mechanisms, this results in an increased pressure on forest resources, diverging from the principal objective of REDD+. We note a gap between the REDD+ narratives at international level (i.e. coupling development with a climate agenda) and the livelihood interests of farming communities on the ground. We argue that without incorporating agricultural interests and a review of financial incentives in the design of future climate finance mechanisms, objectives of both livelihood improvements and GHG emission reductions will be missed.

Key policy insights
  • REDD+ is positioned as a promising tool to meet climate, conservation and development targets. However, these expectations are not being met in practice as the interests of smallholder farmers are poorly addressed.

  • REDD+ policy developers and implementers need more focus on understanding the interests and dynamics of smallholder agriculturalists to enable inclusive, realistic and long-lasting projects.

  • For REDD+ to succeed, funders need to consider how to better ensure long-term livelihood security for farming communities.

  相似文献   
22.
Traditional approaches to risk communication ignore the emotional, cognitive and social factors that interact to influence the meaning people attribute to hazards and protective actions. The aim of this study was to investigate the emotional and cognitive factors predicting preparedness intention and community’s preparedness for flood hazards. A cross-sectional study was conducted between June and July 2015, in Dire Dawa town, Ethiopia. Using stratified systematic random sampling, a structured questionnaire was administered to individuals aged 18 and over in 660 households. Data were analyzed using structural equation modeling (SEM) (STATA version 13.0). The study participants’ mean age was 34 years, ranging from 18 to 80 (SD?=?12) with equal gender balance. SEM analysis revealed that the total effects of preparedness intention (path coefficient (β)?=?0.202, 95% CI: [0.036, 0.369]), past flood disaster experience (β?=?0.034, 95% CI: [0.008, 0.061]), trust (β?=?0.100, 95% CI: [0.059, 0.142]), anxiety (β?=?0.026, 95% CI: [0.018, 0.034), positive outcome expectancy (β?=???0.139, 95% CI: [??0.253, ??0.026]), negative outcome expectancy (β?=?0.105, 95% CI: [0.062, 0.149]), perceived flood likelihood (β?=?0.049, 95% CI: [0.012, 0.086]) and consequence (β?=???0.040, 95% CI: [??0.077, ??0.003]) on community preparedness for flood hazards were statistically significant. The main implication of these findings is that people affected by hazard events in the past experience more anxiety and are more likely to participate in community preparedness activities than those who were not affected.  相似文献   
23.
24.
Estimation of sedimentation in reservoirs helps in the management and design of the reservoir's useful capacity. This research was done on the Awash River basin at the Koka Dam Reservoir in Ethiopia. The method applied was the loose integration of the Soil and Water Assessment Tool(SWAT) model and Hydrologic Engineering Center-River Analysis System(HEC-RAS) model for the estimation of the sediment load reaching the reservoir. The SWAT model was used for the estimation of erosion at the catchment level,and the HEC-RAS model was applied to estimate the sediment transport in the river channel. The implemented method allows sedimentation in the floodplains and bed shear stress to be considered in the sediment modeling, which cannot be considered in the SWAT model. In addition, the river cross sectional properties and the hydrodynamic processes in the rivers were considered in the modeling process. The data used in this study are a combination of i) observed data collected by government agencies, ii) data available online in data repositories, and iii) data extracted from remote sensing in the Shuttle Radar Topographic Mission(SRTM) Digital Elevation Model(DEM). The calibration and validation of the SWAT model was done by using Sequential Uncertainty Fitting(SUIF-2) calibration and validation tools. The HEC-RAS model was calibrated by adjusting the roughness factor. The output from the integrated approaches gives better estimates of flow and sediment near the inlet to the reservoir, with coefficients of determination of 0.85 and 0.67, respectively, and Nash Sutcliffe coefficients of model fit efficiency of 0.90 and 0.62, respectively, for daily simulations.  相似文献   
25.
Abstract

Knowledge of rainfall characteristics is important for estimating soil erosion in arid areas. We determined basic rainfall characteristics (raindrop size distribution, intensity and kinetic energy), evaluated the erosivity of rainfall events, and established a relationship between rainfall intensity I and volume-specific kinetic energy KEvol for the Central Rift Valley area of the Ethiopian highlands. We collected raindrops on dyed filter paper and calculated KEvol and erosivity values for each rainfall event. For most rainfall intensities the median volume drop diameter (D50) was higher than expected, or reported in most studies. Rainfall intensity in the region was not high, with 8% of rain events exceeding 30 mm h-1. We calculated soil erosion from storm energy and maximum 30-min intensity for soils of different erodibility under conditions of fallow (unprotected soil), steep slope (about 9%) and no cover and management practice on the surface, and determined that 3 MJ mm ha-1 h-1 is the threshold erosivity, while erosivity of >7 MJ mm ha-1 h-1 could cause substantial erosion in all soil types in the area.
Editor Z.W. Kundzewicz; Associate Editor Q. Zhang  相似文献   
26.
Abstract

The feasibility of using a geographic information system (GIS) to evaluate the subsurface transport of volatile organic compounds (VOCs) is evaluated. A GIS analysis based on selected soil properties and a flow path model were used to demonstrate the visualization of a probable path taken by diffusing VOC vapors in the vadose zone. The model uses soil properties such as texture, organic matter content, water content, bulk density, and permeability as path finding indices. The values of the soil properties used in the validation of this model were obtained from the respective County Soil Survey Reports. The various combinations of these soil properties resulted in deviations from the anticipated path taken by the diffusing organic vapors as they migrated through the subsurface.

The model was evaluated using two soil systems and estimated diffusion coefficients. A proportionality constant (k) was calculated and used in conjunction with the assigned soil property values in the calculation of diffusion coefficients (Df) for trichloroethylene (TCE) vapors for each soil system. For each case, the model depicts the probable path taken by the VOC vapors as being the route through the soils having characteristics most favorable for chemical migration. Specifically, the soils along the predicted flow path have combinations of high moisture contents, low bulk densities, clay and organic matter contents as well as higher porosity and permeability than soils along any other possible flow path in the given soil systems.  相似文献   
27.
We studied current recruitment failure of Dobera glabra, an important famine-food throughout the dryland parts of the Horn of Africa. The species has previously been found to have recalcitrant seeds, a strategy not common for plants in dryland areas. We experimentally tested (1) how germination capacity of D. glabra is affected by seed form, storage period and moisture under nursery conditions, and (2) how seed predation by vertebrate herbivore and seed exposure at germination site affect germination under field conditions in northern Afar rangelands, Ethiopia. D. glabra seeds that received either mulching or supplementary watering (3 days/week) had a higher germination success than controls. The seeds are probably desiccation sensitive since stored seeds had poor germination performance compared to fresh seeds. Seeds in the rangeland plots protected from herbivores had significantly higher germination success compared to open plots. Our findings demonstrate that seed predation and moisture limitation highly reduced the germinability of the recalcitrant D. glabra seeds, indicating that the species might have persisted due to past wetter periods and low herbivore density in dry environments.  相似文献   
28.
The magnetic fields in the solar atmosphere structure the plasma, store free magnetic energy and produce a wide variety of active solar phenomena, like flare and coronal mass ejections (CMEs). The distribution and strength of magnetic fields are routinely measured in the solar surface (photosphere). Therefore, there is considerable interest in accurately modeling the 3D structure of the coronal magnetic field using photospheric vector magnetograms. Knowledge of the 3D structure of magnetic field lines also help us to interpret other coronal observations, e.g., EUV images of the radiating coronal plasma. Nonlinear force-free field (NLFFF) models are thought to be viable tools for those task. Usually those models use Cartesian geometry. However, the spherical nature of the solar surface cannot be neglected when the field of view is large. In this work, we model the coronal magnetic field above multiple active regions using NLFFF extrapolation code using vector magnetograph data from the Synoptic Optical Long-term Investigations of the Sun survey (SOLIS)/Vector Spectromagnetograph (VSM) as a boundary conditions. We compare projections of the resulting magnetic field lines solutions with their respective coronal EUV-images from the Atmospheric Imaging Assembly (SDO/AIA) observed on October 15, 2011 and November 13, 2012. This study has found that the NLFFF model in spherical geometry reconstructs the magnetic configurations for several active regions which agrees to some extent with observations. During October 15, 2011 observation, there are substantial number of trans-equatorial loops carrying electric current.  相似文献   
29.
Measurements of magnetic fields and electric currents in the pre-eruptive corona are crucial to the study of solar eruptive phenomena, like flares and coronal mass ejections (CMEs). However, spectro-polarimetric measurements of certain photospheric lines permit a determination of the vector magnetic field only at the photosphere. Therefore, there is considerable interest in accurate modeling of the solar coronal magnetic field using photospheric vector magnetograms as boundary data. In this work, we model the coronal magnetic field above multiple active regions with the help of a potential field and a nonlinear force-free field (NLFFF) extrapolation code over the full solar disk using Helioseismic and Magnetic Imager (SDO/HMI) data as boundary conditions. We compare projections of the resulting magnetic field lines with full-disk coronal images from the Atmospheric Imaging Assembly (SDO/AIA) for both models. This study has found that the NLFFF model reconstructs the magnetic configuration closer to observation than the potential field model for full-disk magnetic field extrapolation. We conclude that many of the trans-equatorial loops connecting the two solar hemispheres are current-free.  相似文献   
30.
Extrapolation codes for modelling the magnetic field in the corona in Cartesian geometry do not take the curvature of the Sun’s surface into account and can only be applied to relatively small areas, e.g., a single active region. We apply a method for nonlinear force-free coronal magnetic field modelling of photospheric vector magnetograms in spherical geometry which allows us to study the connectivity between multi-active regions. We use Vector Spectromagnetograph (VSM) data from the Synoptic Optical Long-term Investigations of the Sun (SOLIS) survey to model the coronal magnetic field, where we study three neighbouring magnetically connected active regions (ARs 10987, 10988, 10989) observed on 28, 29, and 30 March 2008, respectively. We compare the magnetic field topologies and the magnetic energy densities and study the connectivities between the active regions. We have studied the time evolution of the magnetic field over the period of three days and found no major changes in topologies, as there was no major eruption event. From this study we have concluded that active regions are much more connected magnetically than the electric current.  相似文献   
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