非洲旱灾的时序变化及健康风险评估

为分析25 a 来非洲旱灾的时间变化趋势及其对各国人口健康的风险，利用1990―2014 年国际灾害数据库（EM-DAT）数据对非洲干旱灾害发生次数、百万人口受影响人数等进行统计，分析其年际变化规律；基于灾害风险评估危险性、暴露性、脆弱性、抗灾能力4 要素，建立非洲旱灾健康风险评估模型，并结合非洲旱灾的主要健康效应，建立多指标综合评价体系，确定权重，对各国旱灾健康风险进行定量评估。结果表明：1）受全球气候变化和大尺度环流异常的影响，非洲干旱灾害发生次数呈波动上升趋势。2）霍乱、营养不良作为旱灾的主要健康效应，主要与旱灾发生频次、影响人数、人口总量、获改善饮用水人口比例、获改善卫生设施人口比例、15 岁以下儿童比例、农村人口比例、政府稳定等自然、社会经济因素有关。3）旱灾发生频次较高的地区危险性较大，对人体健康威胁较严重，而人口总量较大的国家对旱灾暴露量较大，增加了健康风险。改水改厕可提高饮 用水的卫生条件，既减小霍乱与其他水传疾病的流行，也对减少营养不良率起着至关重要的作用。政府稳定度高是国家防灾、抗灾能力建设的基本保障，而农村人口比例、15 岁以下儿童比例为粮食不安全的主要脆弱人群，受灾害健康威胁相对较大。4）从西非马里、尼日尔向东延伸至东非之角的索马里，再向南至南非，因旱灾发生频率高、人口暴露量大、脆弱性大且应灾能力相对较弱，成为旱灾健康风险较高地区。

Temporal Variation and Health Risk Assessment of Drought Disasters in Africa

This paper studied the time trend of drought disaster in recent 25 years in Africa and its health risks of 54 African countries. Inter-annual changes of drought frequency and affected rate per million people were analyzed with the data from 1990 to 2014 recorded in the International Disaster Database (EM-DAT). Based on four elements of disaster risk assessment, including hazard, exposure, vulnerability and adaptability, a health risk assessment model of drought disaster in Africa was established. In order to make quantitative health risk assessment of drought disaster, a multi-index comprehensive evaluation system was established and index weight was determined, combined with the main health effects of drought in Africa. The result showed that the occurrence of drought disasters in Africa was fluctuating from 1990 to 2014 due to the impacts of global climate change and large scale circulation anomalies. The main health effects of drought disasters, such as cholera and malnutrition, were significantly correlated to drought frequency, affected population, total population, percentage of the people with access to improved water source and sanitation facilities, percentage of the population in age from 0-14, proportion of rural population, political stability, and absence of violence/terrorism index. Owing to high drought frequency, population exposure, vulnerability and relatively weak disaster adaptation capacities, the high health risk areas were distributed mainly from Mali in West Africa to Somali in the corner of East Africa eastwardly, then to South Africa southwardly. Drought hazards were more severe in the areas with higher drought frequencies, and exposures were bigger in the areas with a larger total population, where human health threats or risks were more serious. Improvements to lavatories and sanitation facilities can upgrade the conditions of population’s drinking water, and reduce the prevalence of malnutrition, cholera and other water-borne diseases. Nations with high degrees of stability provided basic guarantees upon which to build a nation’s disaster prevention capacity and disaster adaptability. Rural populations and children under 15 years of age were more vulnerable population groups when facing drought disasters and/or food insecurity. Hence, the larger the proportion of the rural population was, and the more the children under 15 years of age were, the higher the malnutrition rate and drought risk would be.