IN THE WAY OF DEVELOPMENT: INDIGENOUS LAND‐RIGHTS ISSUES IN MALAYSIA*     

S. ROBERT AIKEN  COLIN H. LEIGH 《Geographical review》2011,101(4):471-496

The Malaysian government regards the country's indigenous peoples as “backward” and in need of “modernization.” It aims to assimilate them into the so‐called mainstream society and to incorporate their lands and resources into national and global markets. These policy objectives leave little scope for indigenous groups to pursue their own life projects. Indigenous communities want to share in the benefits of economic development, but they are not prepared to give up their lands, cultures, and identities to obtain them. They have attempted to ward off the negative consequences of development projects by forming advocacy nongovernmental organizations, engaging in various forms of resistance, and seeking redress of their grievances in the courts. Most of all, they want recognition of their rights to land and place. The efficacy of their agency is severely hampered by a battery of repressive laws and by their own political weakness.  相似文献   

Climate change impacts on Namibia's natural resources and economy     

HANNAH REID  LINDA SAHLéN  JESPER STAGE  JAMES MACGREGOR 《Climate Policy》2013,13(5):452-466

Climate change is likely to exacerbate the dry conditions already experienced in southern Africa. When rainfall does come, it is likely to be in bursts of greater intensity, leading to erosion and flood damage. However, these predictions have had very little influence on policy in southern African countries. Computable general equilibrium (CGE) model simulations for Namibia indicate that over 20 years, annual losses to the Namibian economy could be up to 5% of GDP, due to the impact that climate change will have on its natural resources alone. This will affect the poorest people the most, with resulting constraints on employment opportunities and declining wages, especially for unskilled labour in rural areas. Namibia must take steps to ensure that all its policies and activities are ‘climate proofed’ and that it has a strategy to deal with displaced farmers and farm workers. The need to mainstream climate change into policies and planning is clear, and it is the responsibility of industrialized nations, who have largely created the problem of climate change, to help Namibia and other vulnerable countries cope with climate change impacts and plan for a climate-constrained future.  相似文献   

A first-order analysis of the potential rôle of CO₂ fertilization to affect the global carbon budget: a comparison of four terrestrial biosphere models     

DAVID W. KICKLIGHTER  MICHELE BRUNO  SILKE DÖNGES  GERD ESSER  MARTIN HEIMANN  JOHN HELFRICH  FRANK IFT  FORTUNAT JOOS  JÖRG KADUK  GUNDOLF H. KOHLMAIER  A. DAVID McGUIRE  JERRY M. MELILLO  ROBERT MEYER  BERRIEN MOORE III  REAS NADLER  I. COLIN PRENTICE  WALTER SAUF  ANNETTE L. SCHLOSS  STEPHEN SITCH  UWE WITTENBERG  GUDRUN WÜRTH 《Tellus. Series B, Chemical and physical meteorology》1999,51(2):343-366

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An analysis of regional climate model performance over the tropical Americas. Part II: simulating subseasonal variability of precipitation associated with ENSO forcing     

By ETIENNE TOURIGNY  COLIN G. JONES  † 《地球，A辑:动力气象学与海洋学》2009,61(3):343-356

The El Niño/Southern Oscillation (ENSO) constitutes a major source of potential predictability in the tropics. The majority of past seasonal prediction studies have concentrated on precipitation anomalies at the seasonal mean timescale. However, fields such as agriculture and water resource management require higher time frequency forecasts of precipitation variability. Regional climate models (RCMs), with their increased resolution, may offer one means of improving general circulation model forecasts of higher time frequency precipitation variability.
Part I of this study evaluated the ability of the Rossby Centre regional atmospheric model (RCA), forced by analysed boundary conditions, to simulate seasonal mean precipitation anomalies over the tropical Americas associated with ENSO variability. In this paper the same integrations are analysed, with the focus now on precipitation anomalies at subseasonal (pentad) timescales.
RCA simulates the climatological annual cycle of pentad-mean precipitation intensity quite accurately. The timing of the rainy season (onset, demise and length) is well simulated, with biases generally of less than 2 weeks. Changes in the timing and duration of the rainy season, associated with ENSO forcing, are also well captured. Finally, pentad-mean rainfall intensity distributions are simulated quite accurately, as are shifts in these distributions associated with ENSO forcing.  相似文献   

CHANNEL ADJUSTMENT OF AN UNSTABLE COARSE-GRAINED STREAM: OPPOSING TRENDS OF BOUNDARY AND CRITICAL SHEAR STRESS,AND THE APPLICABILITY OF EXTREMAL HYPOTHESES     

ANDREW SIMON  COLIN R. THORNE 《地球表面变化过程与地形》1996,21(2):155-180

Channel adjustments in the North Fork Toutle River and the Toutle River main stem were initiated by deposition of a 2.5 km³ debris avalanche and associated lahars that accompanied the catastrophic eruption of Mount St. Helens, Washington on 18 May 1980. Channel widening was the dominant process. In combination, adjustments caused average boundary shear stress to decrease non-linearly with time and critical shear stress to increase non-linearly with time. At the discharge that is equalled or exceeded 1 per cent of the time, these trends converged by 1991–1992 so that excess shear stress approached minimum values. Extremal hypotheses, such as minimization of unit stream power and minimization of the rate of energy dissipation (minimum stream power), are shown to be applicable to dynamic adjustments of the Toutle River system. Maximization of the Darcy–Weisbach friction factor did not occur, but increases in relative bed roughness, caused by the concomitant reduction in hydraulic depths and bed-material coarsening, were documented. Predictions of stable channel geometries using the minimum stream power approach were unsuccessful when compared to the 1991–1992 geometries and bed-material characteristics measured in the field. It is concluded that the predictions are not applicable because the study reaches are not truly stable and cannot become so until a new floodplain has been formed by renewed channel incision, retreat of stream-side hummocks, and establishment of riparian vegetation to limit the destabilizing effects of large floods. Further, prediction of energy slope (and consequently stream power) by the sediment transport equations is inaccurate because of the inability of the equations to account for significant contributions of finer grained (sand and gravel) bank materials (relative to the coarsened channel bed) from bank retreat and from upstream terrace erosion.  相似文献   

A garnet–hornblende geothermometer: calibration, testing, and application to the Pelona Schist, Southern California   总被引：1，自引：0，他引：1  

COLIN M. GRAHAM  ROGER POWELL 《Journal of Metamorphic Geology》1984,2(1):13-31

Abstract A garnet–hornblende Fe–Mg exchange geothermometer has been calibrated against the garnet–clinopyroxene geothermometer of Ellis & Green (1979) using data on coexisting garnet + hornblende + clinopyroxene in amphibolite and granulite facies metamorphic assemblages. Data for the Fe–Mg exchange reaction between garnet and hornblende have been fitted to the equation. In K_D=Δ (X_Ca,g) where K_D is the Fe–Mg distribution coefficient, using a robust regression approach, giving a thermometer of the form: with very satisfactory agreement between garnet–hornblende and garnet–clinopyroxene temperatures. The thermometer is applicable below about 850°C to rocks with Mn-poor garnet and common hornblende of widely varying chemistry metamorphosed at low a_O2. Application of the garnet–hornblende geothermometer to Dalradian garnet amphibolites gives temperatures in good agreement with those predicted by pelite petrogenetic grids, ranging from 520°C for the lower garnet zone to 565–610°C for the staurolite to kyanite zones. These results suggest that systematic errors introduced by closure temperature problems in the application of the garnet–clinopyroxene geothermometer to the ‘calibration’data set are not serious. Application to ‘eclogitic’garnet amphibolites suggests that garnet and hornblende seldom attain Fe–Mg exchange equilibrium in these rocks. Quartzo-feldspathic and mafic schists of the Pelona Schist on Sierra Pelona, Southern California, were metamorphosed under high pressure greenschist, epidote–amphibolite and (oligoclase) amphibolite facies beneath the Vincent Thrust at pressures deduced to be 10±1 kbar using the phengite geobarometer, and 8–9kbar using the jadeite content of clinopyroxene in equilibrium with oligoclase and quartz. Application of the garnet–hornblende thermometer gives temperatures ranging from about 480°C at the garnet isograd through 570°C at the oligoclase isograd to a maximum of 620–650°C near the thrust. Inverted thermal gradients beneath the Vincent Thrust were in the range 170 to 250°C per km close to the thrust.  相似文献   

Infiltration of Aqueous Fluid and High Fluid: Rock Ratios During Greenschist Facies Metamorphism: A Discussion   总被引：1，自引：1，他引：1  

WOOD  BERNARD J.; GRAHAM  COLIN M. 《Journal of Petrology》1986,27(3):751-761

Ferry's (1984) analysis of the biotite isograd in pelitic schistsof the Waterville Formation (south-central Maine, U.S.A.) ledto the conclusion that metamorphism had been caused by infiltrationof 1–2 rock volumes of aqueous fluid. We find that thisimportant observation is extremely sensitive to the assumedtemperature of metamorphism and to corresponding uncertaintiesin the thermodynamic data and solution assumptions. Uncertaintiesin the experimental calibrations of the geothermometers areon the order of ? 30?C. In addition, an analysis of the effectsof minor substituents on calcite-dolomite and garnet-biotitegeothermometers indicates that Ferry's (1980) temperatures areabout 40?C too low in the garnet zone. Correcting the phaseequilibria to higher temperatures by this latter amount lowersfluid:rock ratios by an order of magnitude to about 0?1:1. Sincesmall uncertainties have such great effects it is clearly importantto perform careful uncertainty analyses before using Ferry'sapproach to draw wide-ranging conclusions about fluid-rock interactions.Given a 40?C upward revision of temperature it is not necessaryto invoke pervasive infiltration of aqueous fluid as the majoragent of metamorphism. With these low fluid:rock ratios thewater source could reasonably be a thin sequence of underlyingmetapelites and/or the granitic intrusives which accompaniedthe Acadian orogeny.  相似文献   

THE LAST ICE SHEET IN NORTH-WEST SCOTLAND: RECONSTRUCTION AND IMPLICATIONS     

COLIN K. BALLANTYNE  DANNY McCARROLL  ATLE NESJE  SVEIN OLAF DAHL  JOHN O. STONE 《Quaternary Science Reviews》1998,17(12):1149-1184

Recent models of the last Scottish ice sheet suggest that nunataks remained above the ice surface in areas peripheral to the main centres of accumulation. This proposition has been investigated on 140 mountains over an area of 10,000 km² in NW Scotland. Outside the limits of the later Loch Lomond Readvance in this area there is evidence for a single high-level weathering limit that separates glacially eroded terrain from higher areas of in situ frost debris. This limit occurs at altitudes ranging from 425 to 450 m in the Outer Hebrides to >950 m on the mainland, and is best developed on lithologies that resisted breakdown after ice-sheet downwastage. Interpretation of this weathering limit as a periglacial trimline cut by the last ice sheet at its maximum thickness is supported by: (1) joint-depth and Schmidt hammer measurements that indicate significantly more advanced rock breakdown above the weathering limit; (2) a much greater representation of gibbsite (a pre-Late Devensian weathering product) in the clay fraction of soils above the limit; (3) cosmogenic isotope dating of the exposure ages of rock outcrops above and below the limit; (4) the sharpness of the limit at some sites and its regular decline along former ice flowlines; and (5) shear stress calculations based on the inferred altitude and gradient of the former ice surface. Reconstruction of the ice surface based on trimline evidence indicates that the mainland ice shed lay near or slightly east of the present watershed and descended northwards from >900 m to ca. 550 m at the north coast. Independent dispersion centres fed broad ice streams that occupied major troughs. On Skye an ice dome >800 m deflected the northwestwards movement of mainland ice, but the mountains of Rum were over-ridden by mainland ice up to an altitude of ca. 700 m. The Outer Hebrides supported an independent ice cap that was confluent with mainland ice in the Minches. Extrapolation of the trimline evidence indicates that most reconstructions of ice extent are too conservative, and suggests that low-gradient ice streams extended across the Hebridean Shelf offshore. Wider implications of this research are: (1) that blockfields and other periglacial weathering covers are not all of the same age or significance, depending on the resistance of different lithologies to frost weathering; (2) that the contrasting degree of glacial modification in the Western and Eastern Highlands of Scotland may reflect a former cover of predominantly warm-based ice in the former and predominantly cold-based ice in the latter; and (3) that the approach and techniques developed in this study have potential application for constraining ice-sheet models, not only in areas peripheral to the main centres of ice accumulation in Britain and Ireland, but also in other mountain areas where nunataks protruded through warm-based Late Pleistocene ice masses.  相似文献   

'The Time Trail': a lesson learned     

COLIN REID 《Geology Today》1994,10(2):68-69

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