The 21st Century climate challenge

2Climate shocks: risk and vulnerability in an unequal worldLosses of productivitylinked to climate changewill increase inequalitiesbetween rainfed andcommercial producers,undermine livelihoods andadd to pressures that areleading to forced migrationThe implications of this projectionshould not be underestimated. While Indiais a high- growth economy, the benefits havebeen unequally shared and there is a largehuman development backlog. Around 28percent of the population, some 320 millionpeople, live below the poverty line, withthree-quarters of the poor in rural areas.Unemployment among rural labourers, oneof the poorest groups, is increasing, andalmost half of rural children are underweightfor their age. 61 Superimposing incrementalclimate change risks on this large humandevelopment deficit would compromise theambition of ‘inclusive growth’ set out inIndia’s Eleventh Five–Year Plan.Projections for other countries in SouthAsia are no more encouraging:• Climate scenario exercises for Bangladeshsuggest that a 4°C temperature increasecould reduce rice production by 30 percentand wheat production by 50 percent. 62• In Pakistan, climate models simulate agriculturalyield losses of 6–9 percent for wheatwith a 1°C increase in temperature. 63National projections for climate change inother regions confirm potentially large-scaleeconomic losses and damage to livelihoods.In Indonesia, climate models simulating theimpact of temperature changes, soil moisturecontent and rainfall on agricultural productivityshow a wide dispersion of results, with yieldsfalling by 4 percent for rice and 50 percent formaize. Losses will be especially marked incoastal areas where agriculture is vulnerable tosalt water incursion. 64In Latin America, smallholder agricultureis particularly vulnerable, partly because oflimited access to irrigation and partly becausemaize, a staple across much of the region, ishighly sensitive to climate. There is considerableuncertainty in climate model projections forcrop production. However, recent models pointto the following as plausible outcomes:• Smallholder losses for maize yields averagingaround 10 percent across the region, butrising to 25 percent for Brazil. 65• Losses for rainfed maize production willbe far higher than for irrigated productionwith some models predicting losses of up to60 percent for Mexico. 66• Increased soil erosion and desertificationcaused by increased rainfall and highertemperatures in southern Argentina, withheavy precipitation and increased exposureto flooding damaging production of soya inthe central humid Pampas. 67Changes in agricultural production linkedto climate change will have important implicationsfor human development in Latin America.While agriculture accounts for a shrinking shareof regional employment and GDP, it remainsthe source of livelihood for a large section of thepoor. In Mexico, for example, around 2 millionlow-income producers depend on rainfed maizecultivation. Maize is the main food staple forproducers in the ‘poverty-belt’ states of southernMexico, such as Chiapas. Productivity in thesestates is currently around a third of the level inirrigated commercial agriculture, holding backpoverty reduction efforts. Losses of productivitylinked to climate change will increase inequalitiesbetween rainfed and commercial producers,undermine livelihoods and add to pressures thatare leading to forced migration.Water stress and scarcityIPCC projection: Changing climate patternswill have important implications for wateravailability. It is very likely that mountainglaciers and snow cover will continue to retreat.With rising temperatures, changes in runoffpatterns and increased water evaporation,climate change will have a marked impact onthe distribution of the world’s water—and onthe timing of flows.Human development projection: Large areasof the developing world face the imminentprospect of increased water stress. Flows of waterfor human settlements and agriculture are likelyto decrease, adding to already acute pressuresin water-stressed areas. Glacial melting posesdistinctive human development threats. In thecourse of the 21 st Century water supply storedin glaciers and snow cover will decline, posingimmense risks for agriculture, the environmentand human settlements. Water stress will figure94 HUMAN DEVELOPMENT REPORT 2007/2008