Enabling adaptation? Lessons from the new ‘Green Revolution’ in Malawi and Kenya     

Sally Brooks 《Climatic change》2014,122(1-2):15-26

This article explores the extent to which efforts to improve productivity of smallholder agriculture through a new ‘Green Revolution’ in Sub Saharan Africa are likely to enhance the capacity of smallholder farmers to adapt to the impacts of climate change. Drawing on empirical material from Malawi and Kenya, the paper finds more conflicts than synergies between the pursuit of higher productivity through the promotion of hybrid maize adoption and crop diversification as a strategy for climate change adaptation. This is despite an oft-assumed causal link between escape from the ‘low maize productivity trap’ and progression towards crop diversification as an adaptive strategy. In both countries, a convergence of interests between governments, donors and seed companies, combined with a historical preference for, and dependence on maize as the primary staple, has led to a narrowing of options for smallholder farmers, undermining the development of adaptive capacities in the longer term. This dynamic is linked to the conflation of market-based variety of agricultural technologies, as viewed ‘from the top down’, with diversity-in-context, as represented by site-specific and locally derived and adapted technologies and institutions that can only be developed ‘from the bottom up’.  相似文献   

Impact of chemical and meteorological boundary and initial conditions on air quality modeling: WRF-Chem sensitivity evaluation for a European domain     

Mathias Ritter  Mathias D. Müller  Oriol Jorba  Eberhard Parlow  L.-J. Sally Liu 《Meteorology and Atmospheric Physics》2013,119(1-2):59-70

This study evaluates the impact of different chemical and meteorological boundary and initial conditions on the state-of-the-art Weather Research and Forecasting (WRF) model with its chemistry extension (WRF-Chem). The evaluation is done for July 2005 with 50 km horizontal resolution. The effect of monthly mean chemical boundary conditions derived from the chemical transport model LMDZ-INCA on WRF-Chem is evaluated against the effect of the preset idealized profiles. Likewise, the impact of different meteorological initial and boundary conditions (GFS and Reanalysis II) on the model is evaluated. Pearson correlation coefficient between these different runs range from 0.96 to 1.00. Exceptions exists for chemical boundary conditions on ozone and for meteorological boundary conditions on PM₁₀, where coefficients of 0.90 were obtained. Best results were achieved with boundary and initial conditions from LMDZ-INCA and GFS. Overall, the European simulations show encouraging results for observed air pollutant, with ozone being the most and PM₁₀ being the least satisfying.  相似文献   

Sedimentary stable carbon isotope evidence of late Quaternary vegetation and climate change in highland Costa Rica     

Chad S. Lane  Sally P. Horn  Claudia I. Mora  Kenneth H. Orvis  David B. Finkelstein 《Journal of Paleolimnology》2011,45(3):323-338

Continuous terrestrial records of paleoclimate and paleovegetation that extend to the late Pleistocene are rare for the circum-Caribbean uplands. In this study we analyzed the bulk and compound-specific carbon isotope composition of lake sediments spanning this period from Lago de las Morrenas 1 (LM1), a glacial lake in the highlands of southern Costa Rica, for evidence of climate and vegetation changes that may not have been apparent in previous analyses. The stable carbon isotope ratios of n-alkanes typically derived from terrestrial plants (δ¹³C_C27–C33) indicate an increased abundance of C₄ plant taxa during the late Pleistocene and earliest Holocene that may be related to decreased atmospheric carbon dioxide concentrations, increased aridity, or habitat availability. These n-alkane isotope ratios also provide evidence of more arid conditions during the early and late Holocene, and more mesic conditions during the middle Holocene, a pattern prevalent in other paleoclimate records from the region that is thought to be related to millennial-scale dynamics of the intertropical convergence zone (ITCZ). The sensitivity of the LM1 paleorecord to trade wind dynamics provides further support for the role of millennial-scale shifts in ITCZ dynamics in driving neotropical environmental change, and indicates that the effects of ITCZ migration were not limited to the lowlands.  相似文献   

LOS and ‘other minerals’     

Sally Meese 《Marine Policy》1983,7(2):123-124

Emphasis on mining of manganese nodules has led to a rules, regulations and procedures lacuna in the provisions for non-nodule minerals mining. Unless the regime governing the exploitation of‘other minerals’ is improved, the mining of polymetallic sulphides and other non-nodule minerals will be seriously affected.  相似文献   

The case for the defence     

Sally Meese 《Marine Policy》1983,7(1):56-57

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Calibrating pollen data in climatic terms: Improving the methods     

Sally Howe  Thompson Webb 《Quaternary Science Reviews》1983,2(1):17-51

When properly calibrated, Holocene pollen data provide an important source of quantitative information about Holocene climates. Multiple linear regression of modern climate and pollen data allows the development of statistical calibration functions that transform percentages of certain pollen types into quantitative estimates of climatic variables, and these functions, when applied to Holocene pollen data, yield estimates of climatic variables for past times. Confidence intervals for the climatic variables provide estimates of the statistical errors. These interval estimates are based upon the following statistical assumptions: (1) the regression model is appropriate; (2) the errors in measuring the climate variables are independent, normally distributed and have constant variance; and (3) no outliers are present. We outline the steps to be followed in calculating calibration functions, including (1) selecting the calibration region; (2) selecting a pollen sum; (3) analyzing scatter diagrams of a given climate variable against each pollen type; (4) deleting outliers and transforming pollen data; (5) performing the regression; and (6) testing the appropriateness of the statistical assumptions. We used available computer programs for most of this study. In addition, we developed new software to compute the Moran statistic to test for spatial autocorrelation among the regression residuals, using the dual of the Voronoi diagram to describe the spatial relationships among the sites. In order to illustrate the sequence of procedures, we used data from the lower peninsula of Michigan to develop a calibration function for July mean temperature and then used Holocene pollen data from central lower Michigan to estimate past temperatures.  相似文献   

Multiple Quaternary erosion and infill cycles in overdeepened basins of the northern Alpine foreland     

Marius W. Buechi  Hans Rudolf Graf  Peter Haldimann  Sally E. Lowick  Flavio S. Anselmetti 《Swiss Journal of Geoscience》2018,111(1-2):133-167

The cumulative effect of repeated extensive glaciations represents a poorly constrained component in the understanding of landscape evolution in mid-latitude mountain ranges such as the Alps. Timing, extent, and paleo-climatic conditions of these glaciations are generally poorly understood due to the often-fragmentary character of terrestrial Quaternary records. In this context, the sedimentary infills of subglacial basins may serve as important archives to complement the Quaternary stratigraphy over several glacial–interglacial cycles. In this study, sedimentary facies, valley-fill architecture, and luminescence dating are used to describe nine erosional and depositional cycles (Formations A–I) in the Lower Glatt valley, northern Switzerland. These cycles can be related to the ‘Birrfeld’ Glaciation (~ MIS2), the ‘Beringen’ Glaciation (~ MIS6), and up to three earlier Middle Pleistocene glaciations that can be tentatively correlated to the regional glaciation history. Evidence suggests that deep bedrock trough incision and/or partial re-excavation last occurred mainly during the ‘Beringen’ and ‘Habsburg’ Glaciations. Second-order, ‘inlaid’ glacial basins document separate glacier re-advances during the Beringen Glaciation. The arrangement of subglacial basins in the Glatt valley with different sub-parallel or bifurcating bedrock troughs, re-excavated segments, and inlaid basins document changes in the magnitude and the spatial focus of subglacial erosion over time. The Glatt valley may thus serve as a key example for the glacial landscape evolution in many other repeatedly glaciated forelands.  相似文献   

The relative role of constructive and destructive processes in dune evolution on Cape Lookout National Seashore,North Carolina,USA     

Paige A. Hovenga  Peter Ruggiero  Evan B. Goldstein  Sally D. Hacker  Laura J. Moore 《地球表面变化过程与地形》2021,46(14):2824-2840

Coastal dunes are dynamic features that are continuously evolving due to constructive (e.g., wind- and wave-driven sediment transport) and destructive (e.g., elevated total water levels during storm events) processes. However, the relative importance of these processes in determining dune evolution is often poorly understood. In this study, ten lidar datasets from 1997 to 2016 are used to determine the relative role of erosion and accretion processes driving foredune change on the coast of Cape Lookout National Seashore, North Carolina, USA. Beach and dune morphometrics reveal that dune toe locations have generally retreated since 1997, while dune crest heights accreted by 0.01–0.02 m/year. We develop three univariate metrics that represent (1) the potential for erosion, i.e., total water level impact hours per year, (2) accretion, i.e., dune building hours per year, and (3) the relative net effect of foredune accretion and erosion processes, i.e., constructive–destructive dune forcing (CDDF) ratio, and test the correlative power of these metrics in explaining changes in foredune morphology. The total water level impact hours per year metric explained as much as 66% and 67% of the variance in dune crest and toe elevations, respectively, across the nearly two decades of dune evolution. The greatest number of dune building hours per year and largest dunes within the study site co-occurred at locations exposed to the dominant cross-shore wind direction as a result of varying shoreline orientation. The CDDF ratio was positively correlated to changes in the dune toe elevation in approximately 70% of dunes within the study site, outperforming the impact and dune building hours per year metrics. Our results show that these three metrics can provide first-order estimates of dune morphometric change across multiple spatial and temporal scales, which may be particularly useful at sites where lidar acquisition is intermittent.  相似文献   

Family or Enterprise? What shapes the business structures of Australian farming?     

Sally Weller  Erin F. Smith  Bill Pritchard 《The Australian geographer》2013,44(2):129-142

Australian farmers navigate their contemporary circumstances through the use of different business and legal arrangements that are shaped by the commercial realities of farming and the aspirations of farm-owning households. In posing the question ‘Family or Enterprise?’, this paper examines the extent to which various household and farm business indicators are associated with different forms of farm ownership, namely sole proprietorships, partnerships, trusts and companies. Results from a postal survey of farm enterprises in Victoria, Australia suggest that both household and enterprise factors contribute to the business structure used, although the strongest determinants appear to be those factors that are less well understood in the rural geographical and sociological literature: household composition, farmer age and farm size. Greater scrutiny of the business instruments deployed by farmers to manage family and enterprise pressures should inform expectations of the fate of family farming in advanced financialised economies.  相似文献   

Economic evaluation of structural and non-structural flood risk management measures: examples from the Mulde River   总被引：2，自引：2，他引：0  

Volker Meyer  Sally Priest  Christian Kuhlicke 《Natural Hazards》2012,62(2):301-324

The concept of flood risk management, promoted by the EU Floods Directive, tries to mitigate flood risks not only by structural, hydraulic engineering measures, but also by non-structural measures, like, e.g., land-use planning, warning and evacuation systems. However, few methods currently exist for the economic evaluation of such non-structural measures and, hence, their comparison with structural measures. The objective of this paper is to demonstrate the potential benefits of employing a wider range of economic appraisal methods for flood projects, in particular, it provides examples and applications of methodologies which may be employed to evaluate non-structural measures and their transaction costs. In two case studies at the Mulde River, Germany, two non-structural measures, a resettlement option and a warning system, are evaluated and compared with structural alternatives with regard to their effectiveness, cost-effectiveness and efficiency. Furthermore, a simple approach is tested in order to show the transaction costs of these measures. Case study results show that the choice of evaluation criteria can have a major impact on the assessment results. In this regard, efficiency as an evaluation criterion can be considered as superior to cost-effectiveness and effectiveness as it is also able to consider sufficiently the impacts of non-structural measures. Furthermore, case study results indicate that transaction costs could play an important role, especially with non-structural measures associated with land-use changes. This could explain why currently these kinds of measures are rarely selected by decision makers.  相似文献