The 21st Century climate challenge

2Climate shocks: risk and vulnerability in an unequal worldFloods and tropical stormsThere are large margins of uncertainty inprojections for populations exposed to riskfrom flooding. 85 Accelerated disintegration ofthe West Antarctic ice sheet could multiply sealevelrises by a factor of five over and above theceiling predicted by the IPCC. However, evenmore benign scenarios are a source of concern.One model using an IPCC scenario forhigh population growth estimates the numberof additional people experiencing coastalflooding at 134–332 million for a 3–4°C risein temperature. 86 Factoring in tropical stormactivity could increase the numbers affected to371 million by the end of the 21 st Century. 87Among the consequences of a 1-metre rise insea levels:• In Lower Egypt, possible displacement of 6million people and flooding of 4,500km2 offarmland. This is a region marked by highlevels of deprivation in many rural areas,with 17 percent of the population—some4 million people—living below the povertyline. 88• The displacement of up to 22 million peoplein Viet Nam, with losses of up to 10 percentof GDP. Flooding and more intensive stormscould slow human development progressin major population areas, including theMekong Delta (box 2.10).• In Bangladesh, one metre rise in sea level wouldinnundate 18 percent of land area, directlythreatening 11 percent of the population.The impact on river levels from sea rises couldaffect over 70 million people. 89While most of the people affected by risingsea levels live in a small number of countrieswith large populations, the impacts will befar more widely distributed (table 2.5). Formany low-lying small-island states, rising sealevels and storms point to a highly predictablesocial, economic and ecological crisis. For theMaldives, where 80 percent of the land area isless than 1 metre above sea level, even the mostBox 2.10Climate change and human development in the Mekong DeltaOver the past 15 years, Viet Nam has made spectacular progress inhuman development. Poverty levels have fallen and social indicatorshave improved, putting the country ahead of schedule on almostall of the MDGs. Climate change poses a real and imminent dangerto these achievements—and nowhere more so than in the MekongDelta.Viet Nam has a long history of dealing with extreme weather.Located in a typhoon zone, with a long coastline and extensiveriver deltas, the country is close to the top of the natural disastersleague table. On average, there are six to eight typhoonseach year. Many leave an extensive trail of destruction, killingand injuring people, damaging homes and fi shing boats, anddestroying crops. The country’s 8,000 kilometres of sea and riverdykes, some of which have been developed through communallabour over centuries, testify to the scale of national investmentin risk management.The Mekong Delta is an area of special concern. One of themost densely populated parts of Viet Nam, it is home to 17.2 millionpeople. It is also the ‘rice basket’ of the country, playing a criticalrole in national food security. The Mekong Delta produces halfof Viet Nam’s rice and an even larger share of fi sheries and fruitproducts.The development of agriculture has played a pivotal role inpoverty reduction in the Mekong Delta. Investment in irrigation andsupport for marketing and extension services has enabled farmersto intensify production, growing two or even three crops a year.Farmers have also constructed dykes and embankments to protecttheir fi elds from the fl ooding that can accompany typhoons andheavy rains.Climate change poses threats at several levels. Rainfall is predictedto increase and the country will face more intensive tropicalstorms. Sea levels are expected to rise by 33 cm by 2050 and 1metre by 2100.For the low-lying Mekong Delta this is a particularly grim forecast.The sea-level rise projected for 2030 would expose around45 percent of the Delta’s land area to extreme salinization and cropdamage through flooding. Crop productivity for rice is forecast tofall by 9 percent. If sea levels rise by 1 metre, much of the Deltawould be completely inundated for some periods of the year.How might these changes impact on human development inthe Mekong Delta? While poverty levels have been falling, inequalityhas been increasing, driven partly by high levels of landlessness.There are still 4 million people living in poverty in the Delta. Manyof these people lack basic health protection and school drop-outrates for their children are high. For this group, even a small declinein income or loss of employment opportunities linked to floodingwould have adverse consequences for nutrition, health and education.The poor face a double risk. They are far more likely to live inareas vulnerable to flooding—and they are less likely to live in morerobust permanent homes.Source: Chaudhry and Ruysschaert 2007; Nguyen 2007; UNDP and AusAID 2004.100 HUMAN DEVELOPMENT REPORT 2007/2008