Water under pressure
L. BONAVENTURE/AFP/GETTY IMAGES
More than a billion people do not have access to safe drinking water and two billion have inadequate sanitation. This is despite two international decades, a millennium declaration goal, two international years and a string of global celebratory days — all dedicated to drinking-water or sanitation. Why has progress been so slow?
One reason could be that the current global targets — the Millennium Development Goals — do not provide sufficient incentives for all nations to ensure that everyone has access to water and sanitation (see page 283). Another reason is that the pressures on water resources are continuing to rise: whether through population growth, economic development or climate change (see page 270).
The effects of water shortages are already spilling over from health and sanitation into key economic activities such as agriculture and energy production. Here the challenges are clear, if not fully appreciated: agriculture could easily require twice as much water in the next few decades (see page 273). And the global demand for energy is projected to rise by 57% by 2030 (see page 285).
It we want to improve global access, it is time to rethink our strategies to water, and to respond to global trends in food and energy production.
New concepts are emerging, with experts and policy-makers stressing simple solutions to improve crop yields in the rain-fed areas where many of the world's rural poor live. This is preferable to expanding the area of irrigated farmland, which is already the biggest consumer of freshwater worldwide.
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Growing energy demands will require a more integrated strategy for managing freshwater — to prevent cities and farms, or upstream and downstream users, from coming into conflict. This sort of joined-up policy-making has been sorely lacking, but will be crucial to water management at the river basin, and at both regional and transnational scales (see page 253).
Elsewhere in the issue, a Review Article (see page 301) highlights the purification technologies that scientists hope will improve access to safe drinking water. An Essay (see page 291) explains how physicists still argue over theories about the structure of water. And Books & Arts reviews a television documentary on the privatization of water supplies (see page 288).
译文:
日益紧张的用水问题
日益紧张的用水问题
勒.博纳旺蒂尔/AFP/加蒂 拍摄
尽管我们制定的两个国际行动十年，联合国千年发展目标，两个国际年以及一系列的全球纪念日都是致力于解决饮水或卫生设备，但全球仍有超过10亿的人无法饮用到安全的水，与此同时，还有20亿的人没有最够的卫生设备。人们不禁要问为什么进展如此缓慢？
其中的一个原因便是当今世界的发展方向。联合国千年发展目标并不足以让每个国家都有足够的动力来保障人人都能有安全的饮用水和卫生设备。（看第283页）另一原因则是日益增长的用水压力，无论是来自人口增长，还是经济发展，亦或是气候变化。（看第270页）
水资源匮乏所产生的效应已经不仅仅局限于健康和卫生问题，其影响已经扩散到了诸如农业和能源生产这类核心经济活动。如今我们所面临的挑战是显而易见的。如果再不给予充分的重视，在未来的数十年中，农业生产将轻松地耗费掉现如今所需两倍的水。到2030时，全球能源需求将上涨57%。
如果我们想要改善这样的状况，重新思考用水战略，根据食物和能源生产趋势做出反应刻不容缓。
新的概念逐步浮现，专家和政策制定者把更多的目光投向用简单的方法来提高旱作地区庄稼产量，而这些地区往往又是农村贫困人口的聚居地。对于早已是全球淡水消耗第一大户的农田灌溉而言，采用这样的方法比之进一步扩大农田灌溉面积来解决问题，孰优孰劣，一目了然。
建议
日益增长的能源需求更需要一个综合的淡水管理策略，以防城市和农村，上游和下游的用户产生冲突。目前这种加入政策制定的行动还很少见，但这对于江河流域，以及地区性和跨国界的水资源管理是非常重要的。(看第253页）
另外在这个问题上，有一片评述文章（看第301页）强调科学家希望能够用净化科技提高饮用水安全。还有一篇文章（看第291页）解释了物理学家们仍在争论水的结构。书本和艺术这一栏目则回顾了关于供水私有化的电视纪录片。