Studies on the short- to medium- term effects of a disaster on poverty abound.3 Many survivors of disasters, rich and poor, recover fully, but a few do not. Healthy people survive temporary deprivation, but elder people and women are particularly vulnerable. Even temporary malnourishment could perma- nently stunt growth and lower cognitive abilities among children younger than three. While much has been written on short-run effects, panel data to examine the longer term effects on human welfare, some more subtle than others, are scant; but the absence of data does not mean the absence of a problem. Some new studies explore the sufferings of survivors, particularly children.
Declines in schooling and health
Enrollment rates for children aged 7–15 fell by about 20 percent in parts of Côte d’Ivoire with extreme rainfall changes between 1986 and 1987 rela- tive to unaffected regions (Jensen 2000). Earthquakes had similar effects: school attendance fell by almost 7 percent among households heaviest hit by the two strong earthquakes that affected El Salvador in 2001 (Santos 2007). Children in households most affected were about three times more likely to work than attend school.
Temporary withdrawal from school sometimes becomes permanent: chil- dren withdrawn from schools during droughts in Central Mexico between 1998 and 2000 were about 30 percent less likely to resume their studies (de Janvry and others 2006). Boys in Tanzania worked longer hours after a drought: a 5.7 hour increase in work reduces their schooling by a year, observed 10 years later (Beegle, Dehejia, and Gatti 2006).
Complementing these country studies in a background paper for the report, Cuaresma (2009) conducts a cross-country analysis of the link between disasters and human capital accumulation (measured by second- ary school enrollment). The fi ndings are that those more exposed to earth- quakes between 1980 and 2000 have lower secondary school enrollment rates: 1.65 percentage points lower for a country with mean occurrence of quakes compared with a country with no quakes.4 Another study fi nds that households with a higher probability of experiencing fl oods in Ban- gladesh are more likely to “hold” extra years of schooling relative to land (Yamauchi, Yohannes, and Quisumbing 2009a, 2009b). In Ethiopia and Malawi, exposure to highly frequent droughts in some cases reduced school- ing investment. And asset holdings prior to disasters, especially household human capital stock, help maintain schooling investments.
Disasters reduce school enrollment: parents want education for their children but may pull them out temporarily after a disaster to help with more pressing tasks, or because schools have been disrupted. Resuming education requires effort, and a permanent loss or decline may be because many children (or parents) give up or because teaching remains disrupted. In either case, something must be done; what, depends on the details. More- over, cognitive and analytical abilities—only imperfectly related to school- ing—could be affected even without reductions in school enrollment.
Visits to the doctor decline after a disaster, but with little effect on health. After Hurricane Mitch in 1998, sick children in affected areas were 30 per- cent less likely to be taken to clinics but with no signifi cant difference in the prevalence of illness. The larger point: outputs, like cognition or health, are harder to measure than declines in school enrollment or doctor visits.5 Increased stunting . . .
Malnourishment has adverse effects, especially on young children, and this occurs during extended droughts, especially in Africa. Children who lose weight may catch up later (Foster 1995), but while “wasting” (low weight-
Chapter 2: Measuring Disasters’ Many Effects 45
to-height ratio) is reversible, “stunting” (low height-to-age ratio) is almost always permanent (fi gure 2.1).
In a group of 400 rural households, children aged 12 to 24 months at the time of the 1982–84 droughts in Zimbabwe were 2.3 centimeters shorter in late adolescence (Alderman and others 2006). In the Kagera region of Tan- zania, children younger than 5 years exposed to a drought in 1991–94 were roughly 1 percent shorter than the population’s median height 10 years after (Alderman and others 2009). In Ethiopia, children either in uterus or younger than 36 months affected by the 1984 famine were 3 centimeters shorter than other comparable children 10 years later (Porter 2008). In China, rural adults who were children in the 1959 and 1962 famines were 3.03 centimeters shorter (Chen and Zhou 2007). And in Indonesia, females born in a year with 20 percent higher rainfall are 0.14 centimeters taller (Maccini and Yang 2008).
. . . and diminished cognitive abilities
Malnutrition that causes stunting also diminishes cognitive skills by inhib- iting learning (reducing schooling) and productivity. In rural Zimbabwe and rural Tanzania, malnutrition reduces the years of schooling completed. In both cases, after fi nding that droughts reduce children’s height, their
Figure 2.1 Undernourished children become shorter adults
Note: Z-scores (standard deviation scores) are a system by which a child or a group of children can be compared
to the reference population. For population-based assessment—including surveys and nutritional surveillance— the z-score is widely recognized as the best system for analysis and presentation of anthropometric data. (WHO, http://www.who.int/nutgrowthdb/about/introduction/en/index4.html)
Source: Victora and others 2008.
Attained adult height (centimeters)
180 A. Males
Height-for-age Z score at 2 years Height-for-age Z score at 2 years 175 170 165 160 155 150 145 140 135 < –3 –3 to –2.01 –2 to –1.01
> = –1 Attained adult height (centimeters)
180 B. Females 175 170 165 160 155 150 145 140 135 < –3 –3 to –2.01 –2 to –1.01 > = –1
educational achievements as adolescents were regressed on their height when they were younger. In Zimbabwe, the 12- and 24-month stunted children during the 1982–84 droughts had delayed school enrollment (3.7 months) and lowered grade completion (0.4 grades) 13 to 16 years later. And in Tanzania, schooling at adolescence in 2004 was nearly a year more for a boy in the 95th percentile of height distribution than for another in the 80th percentile, when they were under 5 and exposed to the 1991–94 drought.
Children between 12 and 36 months who are moderately or severely stunted compared with not stunted (height-for-age greater than one nega- tive standard deviation) have reduced cognitive skills (measured through IQ tests) in later childhood (Grantham-McGregor and others 2007).6 For example, in the Philippines, reading and math test scores for children at age 8 who were stunted during childhood were 0.75 standard deviations below that of children not stunted (table 2.1).
Malnourished children become less productive adults: their lower body mass makes manual labor less productive, and their lower cognitive skills make skilled work more diffi cult.7
. . . reduce subsequent earnings
Children malnourished during the 1982–84 drought in Zimbabwe had a 7 percent loss in (extrapolated) lifetime earnings (Alderman and oth- ers 2006). The 1991–94 drought in the Kagera region of Tanzania also reduced lifetime earnings by about 1 percent, a smaller but still signifi cant effect because the sample included older children who were less vulnerable. Similarly, the 1959–61 birth cohort (malnourished in famine) earned less as adults: the 1959 cohort in areas where the death rate is higher by 1 in 1,000 earns 2 percent less per capita (Chen and Zhou 2007).8
Table 2.1 Stunted children have lower cognitive scores
Philippines
South
Africa Indonesia Brazil1 Peru Jamaica2
Cognitive score (8 years, n = 2489) Ravens Matrices (7 years, n = 603)3 Reasoning and arithmetic (9 years, n = 368) Attained grades (18 years, n = 2041) WISC IQ (9 years, n = 72) WAIS IQ (17–18 years, n = 165)3 Reading and arithmetic (17–18 years)3 Not stunted 56.4 0.17 11.2 8.1 92.3 0.38 0.4 Mildly stunted 53.8 (–0.21) 0.05 (–0.12) 10.3 (–0.26) 7.2 (–0.4) 89.8 (–0.20) Moderately or severely stunted 49.6 (–0.54) –0.23 (–.040) 9.7 (–0.43) 6.5 (–0.7) 79.2 (–1.05) –0.55 (–0.93) –0.60 (–1.00)
Note: Data are mean (effect size as unadjusted difference from non-stunted children in z scores).
1. Males only.
2. The sample comprised stunted (< –2SD) children participating in an intervention trial and a non-stunted (> –1SD) comparison group.
3. SD scores.
WISC = Wechsler Intelligence Scale for Children. WAIS = Wechsler Adult Intelligence Scale.
Chapter 2: Measuring Disasters’ Many Effects 47
This effect of nutrition on earnings may act through cognitive skills. Poor nutrition in Guatemala lowered cognitive skills and reduced earnings (Hod- dinott and others 2008). For two groups with 25–42 year olds, those who got nutritional supplements as 0 to 3 year old children had higher wages. Mental health falls—but can recover
Income, consumption, and health are poor proxies of welfare, and Amar- tya Sen suggests measuring welfare by functionings and capabilities—what people accomplish with income, health, and education (Sen 1987). Physical or psychological trauma diminishes welfare even if earnings do not fall.
There is justifi ed concern with the psychological effects of disasters. Nor- ris (2005) reviews 225 studies in developing and developed countries and fi nds that many suffer from post-disaster psychological disorders. But most of these studies address small samples (150 people on average) and very few studies have systematically followed larger samples of affected people over several years. A background paper for this report, using household data employing a baseline collected ten months prior to the 2004 Aceh tsunami, examines the mental health of its adult survivors (Frankenberg and others 2009). Annual follow up surveys in the subsequent four years provided a “before and after” indication of mental wellbeing. For 9,000 adult survivors of the 2004 tsunami in Aceh, post-traumatic stress reaction (PTSR) scores for each respondent in affected areas were high in heavily affected areas as much as 6 to 14 months after the tsunami. But even without treatment, these scores declined with time (fi gure 2.2).
This analysis also addressed the association between disaster-induced PTSR and key socioeconomic outcomes such as physical health, demographics
Figure 2.2 Post-traumatic stress reaction (PTSR) scores fall over time in all tsunami-affected areas
Source: Frankenberg and others 2009.
Mean PTSR score 4 2005 2006 2007 2008 6 8 10 Exposure to
(widowhood), work, income, and household wealth. It controlled for com- munity-fi xed effects and damage area as well as the age, gender, and edu- cation of each respondent, fi nding little infl uence of initial PTSR on most outcomes.9
It may not be possible to generalize the Aceh fi ndings, especially because mental health issues are culture and condition sensitive. But if these fi nd- ings hold in other contexts, they have important policy implications. And though mental health counseling was relatively unavailable in the after- math of Aceh, much PTSR faded over time and no long-term socioeco- nomic effects were reported. This suggests that it may be better to channel scarce resources in a disaster’s immediate aftermath toward traditional relief activities as opposed to early-stage mental health interventions. The enduring response, however, may say otherwise. As reconstruction begins, PTSR declines, but new cases of adverse behavior may emerge among some people. And these people may benefi t from targeted mental health interven- tions. Clearly though, more work is needed to explore the links between mental health and disasters. Future research should consider the composi- tion of this more vulnerable group and how to help them lead better lives after a disaster.