本文格式为Word版，下载可任意编辑英文—土地退化控制及其全球环境效益 land degradation Revised 12June 2022;Accepted 22December 2022 ABSTRACT Acknowledged by world leaders as a global problem,land degradation has been taken seriously in three ways:its extent and the proportion of the global population affected;international environmental policy responses;and its inter-relation with other global environmental issues such as biopersity.Messages about land degradation have,however,suffered from abuses,which have rendered appropriate policy responses ineffective.For control to be effective,the paper argues that the synergies between land degradation and the two other main global environmental change components (biopersity and climate change)should be more fully exploited.A focus on the interlinkages,of which there are six possible permutations,is fully supported by empirical ?ndings that suggest that land degradation control would not only technically be better served by addressing aspects of biopersity and climate change but also that international ?nancing mechanisms and the major donors would ?nd this more acceptable.The DPSIR (Driving Force,Pressure,State,Impacts,Response)conceptual framework model is used to illustrate how land degradation control could be more effective,tackling not only the drivers of change but also major developmental issues such as poverty and food insecurity.Copyright #2022John Wiley global environment;UN environmental conventions;synergies;biopersity;climate change LAND DEGRADATION IN GLOBAL CONTEXT Land degradation is widely recognized as a global problem associated with deserti?cation in arid,semiarid and dry sub-humid zones,commonly called the ‘drylands’.Yet,land degradation is a contested topic in its determinants,degree,distribution and effects.While long associated with drylands,which cover some 47per cent of the globe’s surface (UNEP,1997),land degradation is considered by many observers to be highly variable,discontinuous,arising from different causes and affecting people differentially according to their economic,social and political circumstances (e.g.Mortimore,1998).Uncertainty as to the extent and impact of land degradation is rife.Some sources routinely report that up to 70per cent of all drylands are ‘deserti?ed’;others suggest that the ?gure is no more than 17per cent (see Reynolds et al.,2022).Amidst such discrepancies,it is dif?cult to identify whether and how land degradation should be an issue of global concern.The overall aim of this paper,then,is to explore how the process of land degradation,which impacts upon people locally and differentially,can also be considered to be of global interest with global implications. There are three principal ways that land degradation can be perceived to be global.First,it affects a large number of people over a signi?cant proportion of the earth’s surface.Adams and Eswaran (2000)estimate that it Copyright #2022John Wiley United Nations University,Tokyo;FAO–GEF Land degradation assessment in drylands project;United Nations Environment Programme,Nairobi. 100G.GISLADOTTIR AND M.STOCKING impacts2á6billion people in more than a hundred countries,covering over33per cent of the earth’s land surface. Around73per cent of rangelands in drylands are currently being degraded,together with47per cent of marginal rainfed croplands and a signi?cant percentage of irrigated croplands.The science behind the actual extent of land degradation is open to debate,especially in dryland parts of Africa(Stocking,1996).However,even restrained estimates show that it affects the poor and most marginal rural people world-wide disproportionately.Taking only the world’s drylands,37per cent of the world’s total population live on land that is either potentially or actually 4606e4f8941ea76e58fa04fa,Africa and South America have the largest populations living in drylands,both in terms of numbers and percent:1á4billion,268million and87million people,or42,41and30per cent of each region’s population respectively.The drylands are the home of the world’s poorest and most marginalized people, economically and geographically.The number of poor rural people living in drylands is estimated to be close to one billion(Dobie,2022). Second,land degradation has prompted a stream of national and international policy responses.The Dust Bowl era of the1930s United States prompted the?rst national research programme on soil erosion and its impact (Trimble,1985).Other countries and regions soon emulated this lead:e.g.Brazil(Lal,1977);Sri Lanka(Joachim and Pandithasekera,1930);and the Federation of Rhodesia and Nyasaland,now Zambia,Zimbabwe and Malawi (Jackson,1960).With major increases in funding for erosion research and surveys of soil degradation,a number of international projects were initiated:e.g.the Provisional Methodology for Soil Degradation Assessment(FAO, 1979).Other initiatives included the United Nations Conference on Deserti?cation(UNCOD)in1977and the United Nation。