Modelling global water stress of the recent past: on the relative importance of trends in water demand and climate variability
Modelling global water stress of the recent past: on the relative importance of trends in water demand and climate variability
复制标题
DOI：
10.5194/hess-15-3785-2011
复制
发表时间：
2011-12
影响因子：
6.3
通讯作者：
Y. Wada;L. V. Beek;M. Bierkens
中科院分区：
文献类型：
--
作者：
Y. Wada;L. V. Beek;M. Bierkens
抽象的。在过去的几十年里，人类的用水量增加了一倍多，但可用的淡水资源有限。因此，世界各地区普遍存在缺水现象。在这里，我们首次以0.5°的空间分辨率对过去水资源胁迫的发展进行了全球评估，不仅考虑了气候变化，而且还考虑了1960-2001年期间不断增长的水需求、淡化水的使用和不可再生的地下水开采。农业用水需求是根据过去灌溉面积和牲畜密度估算的。我们根据国内生产总值、能源和家庭消费以及电力生产来估算过去的经济发展，这些数据随后与人口数字一起用于估计工业和生活用水需求。气候变异性是通过全球水文模型PCRGLOBWB由河流、湖泊、湿地和水库中的淡水定义的模拟蓝水可获得性来表示的。因此，我们通过常用的缺水指数将蓝色水的可获得性与相应的净蓝色水总需求量进行比较来定义蓝色水胁迫。结果表明，由于主要用于灌溉的用水需求不断增长，生活在缺水(即中度到高度缺水)条件下的全球人口急剧增加，在1960年至2000年期间，从1708/818年增至3708/1832km3yr−1(毛数/净额)，增加了一倍多。我们估计，1960年有8亿人或27%的全球人口生活在缺水条件下。这一数字最终将增加到26亿，即2000年的43%。结果表明，水资源需求的增加是印度和中国北部等地区水分胁迫加剧的决定性因素，使水分胁迫强度增加了200%，而气候变化往往是极端事件的主要决定因素。然而，我们的结果也表明，在一些新兴和发展中经济体(如印度、土耳其、罗马尼亚和古巴)，过去的一些极端事件是由人类活动驱动的，原因是水需求增加，而不是气候导致的。
Abstract. During the past decades, human water use has more than doubled, yet available freshwater resources are finite. As a result, water scarcity has been prevalent in various regions of the world. Here, we present the first global assessment of past development of water stress considering not only climate variability but also growing water demand, desalinated water use and non-renewable groundwater abstraction over the period 1960–2001 at a spatial resolution of 0.5°. Agricultural water demand is estimated based on past extents of irrigated areas and livestock densities. We approximate past economic development based on GDP, energy and household consumption and electricity production, which are subsequently used together with population numbers to estimate industrial and domestic water demand. Climate variability is expressed by simulated blue water availability defined by freshwater in rivers, lakes, wetlands and reservoirs by means of the global hydrological model PCR-GLOBWB. We thus define blue water stress by comparing blue water availability with corresponding net total blue water demand by means of the commonly used, Water Scarcity Index. The results show a drastic increase in the global population living under water-stressed conditions (i.e. moderate to high water stress) due to growing water demand, primarily for irrigation, which has more than doubled from 1708/818 to 3708/1832 km3 yr−1 (gross/net) over the period 1960–2000. We estimate that 800 million people or 27% of the global population were living under water-stressed conditions for 1960. This number is eventually increased to 2.6 billion or 43% for 2000. Our results indicate that increased water demand is a decisive factor for heightened water stress in various regions such as India and North China, enhancing the intensity of water stress up to 200%, while climate variability is often a main determinant of extreme events. However, our results also suggest that in several emerging and developing economies (e.g. India, Turkey, Romania and Cuba) some of past extreme events were anthropogenically driven due to increased water demand rather than being climate-induced.