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This study measures the impact of fanya juu terraces on the net value of crop income in a high‐rainfall area in the Ethiopian highlands using cross‐sectional multiple plot observations. Using propensity score matching methods we find that the net value of crop income for plots with fanya juu terraces is lower than for plots without fanya juu terraces. This finding makes it difficult to avoid concluding that while the technologies might reduce soil erosion and associated off‐site effects, they do so at the expense of poor farmers in the Ethiopian highlands. Therefore, fanya juu terraces cannot be characterized as a “win‐win” measure to reduce soil erosion. New agricultural technologies need to be profitable to the farmer if they are to be adopted and sustained.  相似文献   

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Evidence from cross-sectional growth regressions suggests that economies dependent on natural resource exports have had slower growth than resource scarce economies. Explanations for this “curse of resources” focus on institutional and market failures caused by resource abundance. With a simple two sector model exhaustible resource model, we demonstrate that the correlation between growth and natural resource abundance can be negative in the absence of market and institutional failures. Since there is no way to distinguish between efficient and inefficient equilibria on the basis of the negative correlation between growth and resource abundance, finding that correlation is not sufficient to conclude resources are a curse, nor is it necessary to find a positive correlation between growth and resources to overturn the resource curse interpretation. We show whether resources are a curse or a blessing for an economy can only be determined by an investigation of the correlation between resource abundance and income levels. Using panel data for U.S. states for the period 1970-2001, we show that resource abundance is negatively correlated with growth rates but positively correlated with income levels.  相似文献   

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Whether a city develops into a more compact one with a higher density or a more sprawling one may affect multiple aspects of the urban environment, including ecosystem health, greenhouse gas emissions, and quality of life. Using panel data gathered from China's cities from 2000 to 2010, we take advantage of the significant variation in the temporal change of density across cities to estimate the relationship between gross urban population density and multiple indicators of urban greenness. Fixed‐effects estimates support the widely held belief that density improves air quality and reduces the per capita carbon footprint. Results also suggest that higher density reduces the growth of road infrastructure and vehicle ownership and promotes walking. While density often translates into proximity and accessibility, higher density does reduce a city's per capita urban park and green space. This study strengthens the urban policy and planning literature with much needed longitudinal evidence. Our overall findings support higher density as opposed to lower density urban development in China.  相似文献   

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It is well established that wet environment potential evapotranspiration (PET) can be reliably estimated using the energy budget at the canopy or land surface. However, in most cases the necessary radiation measurements are not available and, thus, empirical temperature‐based PET models are still widely used, especially in watershed models. Here we question the presumption that empirical PET models require fewer input data than more physically based models. Specifically, we test whether the energy‐budget‐based Priestley‐Taylor (P‐T) model can reliably predict daily PET using primarily air temperature to estimate the radiation fluxes and associated parameters. This method of calculating PET requires only daily minimum and maximum temperature, day of the year, and latitude. We compared PET estimates using directly measured radiation fluxes to PET calculated from temperature‐based radiation estimates at four humid AmeriFlux sites. We found good agreement between P‐T PET calculated from measured radiation fluxes and P‐T PET determined via air temperature. In addition, in three of the four sites, the temperature‐based radiation approximations had a stronger correlation with measured evapotranspiration (ET) during periods of maximal ET than fully empirical Hargreaves, Hamon and Oudin methods. Of the three fully empirical models, the Hargreaves performed the best. Overall, the results suggest that daily PET estimates can be made using a physically based approach even when radiation measurements are unavailable.  相似文献   

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Climate change in Australia has become a political risk (for political parties) and a physical, transitional, and regulatory risk for businesses. Not‐for‐profits (NFPs) and for‐purpose (FPs) organisations, for example, Climate Alliance Limited, have acted in the absence of national climate risk policy, to support businesses to become better informed to manage their exposure to this risk, and helping them to set their own commitments and pathways to low and net zero carbon businesses. The objective of this article is to demonstrate, through the case study method, how one Australian NFP/FP has influenced the business sector and regulation. Climate Alliance Limited has done this through its interventions of (1) sharing case studies (best practices) on successful transitions to a low carbon business model and linking climate risk to business risk; (2) bringing thought leaders (advocacy) from the Bank of England and UK Prudential Regulator into the Australian finance and business sector; and (3) by offering a program (reward and recognition), showcasing how business leaders have and are adapting to climate risks and capturing business value.  相似文献   

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In spring 2011, an unprecedented flood hit the complex eastern United States (U.S.)–Canada transboundary Lake Champlain–Richelieu River (LCRR) Basin, destructing properties and inducing negative impacts on agriculture and fish habitats. The damages, covered by the Governments of Canada and the U.S., were estimated to C$90M. This natural disaster motivated the study of mitigation measures to prevent such disasters from reoccurring. When evaluating flood risks, long‐term evolving climate change should be taken into account to adopt mitigation measures that will remain relevant in the future. To assess the impacts of climate change on flood risks of the LCRR basin, three bias‐corrected multi‐resolution ensembles of climate projections for two greenhouse gas concentration scenarios were used to force a state‐of‐the‐art, high‐resolution, distributed hydrological model. The analysis of the hydrological simulations indicates that the 20‐year return period flood (corresponding to a medium flood) should decrease between 8% and 35% for the end of the 21st Century (2070–2099) time horizon and for the high‐emission scenario representative concentration pathway (RCP) 8.5. The reduction in flood risks is explained by a decrease in snow accumulation and an increase in evapotranspiration expected with the future warming of the region. Nevertheless, due to the large climate inter‐annual variability, short‐term flood probabilities should remain similar to those experienced in the recent past.  相似文献   

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Foreign direct investment is an engine of economic growth. However, it may affect environmental quality (improve or deteriorate it), depending on the context. Under a multivariate framework, this paper aims to investigate the relationship between foreign direct investment and deforestation for Sub‐Sahara African countries with economic growth, trade openness and urbanization as additional determinants of deforestation. The analyses reveal that all variables are non‐stationary and cointegrated based on recent panel data techniques. On applying dynamic ordinary least squares, the long‐run results suggest the validity of the pollution haven hypothesis for some countries, and that of the pollution halo hypothesis for other countries. The findings are also mixed across Sub‐Sahara African countries for trade openness and urbanization. The results from this study suggest that Sub‐Sahara African countries should continue attracting foreign direct investment, while a certain number of them should put more emphasis on controlling deforestation associated with foreign direct investment inflows to limit greenhouse gas concentrations in the atmosphere.  相似文献   

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Community‐based water supply (CBWS) is an example of how a community manages common pool resources (CPR). This results in an alternative approach to solve water supply problems in developing countries by enhancing community participation in managing water supply. This research evaluates the sustainability of five CBWS projects in Cikarang, Indonesia by using Ostrom's design principles, with additional sustainability factors found in the Sustainable Development Goal (SDG) on drinking water and groundwater sustainability. Quinn et al. (2007) criteria were used in the analysis, and the results show that the management of four CBWS institutions were absent and one CBWS institution was weak. With regards to the SDG's drinking water target, the CBWS institutions were unable to comply with safe water standards, and in terms of groundwater sustainability, efforts to monitor and sustain groundwater tables were absent. Results from this research suggest that more focus must be placed on water quality and groundwater sustainability for CBWS projects.  相似文献   

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《中国环保产业》2005,(7):46-47
由福州桑莱思科技开发有限公司开发的G201光催化剂适用于新型环保建材光净化陶瓷和玻璃。主要技术内容一、基本原理利用高效光催化剂的强氧化性与超亲水性原理,以特定技术将上述高效光催化剂镀在陶瓷表面,形成的光催化膜可将光能转化为化学能,起到分解油污、降臭味、耐脏和自动杀灭细菌等作用。光催化膜本身也是一种纳米陶瓷涂层,生产该种陶瓷无需改变原有的陶瓷(包括瓷砖、卫生陶瓷和日用瓷等)生产工艺,仅需附加少量装置和增加两道工序。二、技术关键首先是使用专用高效光催化剂,其次是喷涂和热处理技术。光催化瓷砖环保性能优异,同时能保…  相似文献   

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Changing climate and growing water demand are increasing the need for robust streamflow forecasts. Historically, operational streamflow forecasts made by the Natural Resources Conservation Service have relied on precipitation and snow water equivalent observations from Snow Telemetry (SNOTEL) sites. We investigate whether also including SNOTEL soil moisture observations improve April‐July streamflow volume forecast accuracy at 0, 1, 2, and 3‐month lead times at 12 watersheds in Utah and California. We found statistically significant improvement in 0 and 3‐month lead time accuracy in 8 of 12 watersheds and 10 of 12 watersheds for 1 and 2‐month lead times. Surprisingly, these improvements were insensitive to soil moisture metrics derived from soil physical properties. Forecasts were made with volumetric water content (VWC) averaged from October 1 to the forecast date. By including VWC at the 0‐month lead time the forecasts explained 7.3% more variability and increased the streamflow volume accuracy by 8.4% on average compared to standard forecasts that already explained an average 77% of the variability. At 1 to 3‐month lead times, the inclusion of soil moisture explained 12.3‐26.3% more variability than the standard forecast on average. Our findings indicate including soil moisture observations increased statistical streamflow forecast accuracy and thus, could potentially improve water supply reliability in regions affected by changing snowpacks.  相似文献   

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This paper provides examples from the last fifty years of scientific and technological innovations that provide relatively easy, quick and affordable means of addressing key water management issues. Scientific knowledge and technological innovation can help open up previously closed decision‐making systems. Four of these tools are discussed in this paper: a) the opportunities afforded by virtual water trade; b) the silent revolution for beneficial use of groundwater; c) salt water desalination; and finally, d) the use of remote sensing and geographic information systems (GIS). Together these advances are changing the options available to address water and food security that have been predominant for centuries in the minds of most water decision‐makers.  相似文献   

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Wetland protection and restoration strategies that are designed to promote hydrologic resilience do not incorporate the location of wetlands relative to the main stream network. This is primarily attributed to the lack of knowledge on the effects of wetland location on wetland hydrologic function (e.g., flood and drought mitigation). Here, we combined a watershed‐scale, surface–subsurface, fully distributed, physically based hydrologic model with historical, existing, and lost (drained) wetland maps in the Nose Creek watershed in the Prairie Pothole Region of North America to (1) estimate the hydrologic functions of lost wetlands and (2) estimate the hydrologic functions of wetlands located at different distances from the main stream network. Modeling results showed wetland loss altered streamflow, decreasing baseflow and increasing stream peakflow during the period of the precipitation events that led to major flooding in the watershed and downstream cities. In addition, we found that wetlands closer to the main stream network played a disproportionately important role in attenuating peakflow, while wetland location was not important for regulating baseflow. The findings of this study provide information for watershed managers that can help to prioritize wetland restoration efforts for flood or drought risk mitigation.  相似文献   

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Land management agencies commonly use rapid assessments to evaluate the impairment of gravel‐bed streams by sediment inputs from anthropogenic sources. We question whether rapid assessment can be used to reliably judge sediment impairment at a site or in a region. Beyond the challenges of repeatable and accurate sampling, we argue that a single metric or protocol is unlikely to reveal causative relations because channel condition can result from multiple pathways, processes, and background controls. To address these concerns, a contextual analysis is needed to link affected resources, causal factors, and site history to reliably identify human influences. Contextual analysis is equivalent in principle to cumulative effects and watershed analyses and has a rich history, but has gradually been replaced by rapid assessment methods. Although the approaches differ, rapid assessment and contextual analysis are complementary and can be implemented in a two‐tiered approach in which rapid assessment provides a coarse (first‐tier) analysis to identify sites that deserve deeper contextual assessment (second‐tier). Contextual analysis is particularly appropriate for site‐specific studies that should be tailored to local conditions. A balance between rapid assessment and contextual analysis is needed to provide the most effective information for management decisions.  相似文献   

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