来源：《新科学家》
原文刊登日期：2021年6月16日
本文适合英语二考生
More than half the world’s rivers stop flowing for at least one day per year, according to the first detailed global map of river flow. More rivers than that are expected to run dry if climate change and water management issues aren’t addressed.
根据首份详细的全球河流流动地图，世界上一半以上的河流每年至少断流一天。如果气候变化和水资源管理问题得不到解决，预计将有更多的河流干涸。
Many rivers and streams have natural disruptions to their flow – for example, Himalayan streams that freeze solid in winter and Saharan rivers that dry up for long stretches between rainy seasons. Others sometimes dry up when too much water is extracted for crop irrigation or other human uses.
许多河流和小溪的流动受到了自然干扰——例如，喜马拉雅的河流在冬天会冻结成固体，撒哈拉的河流在雨季之间很长一段时间内会干涸。当太多的水被提取出来用于作物灌溉或其他人类用途时，其他一些河流有时会干涸。
To find out how many rivers have intermittent flows, Mathis Loïc Messager at McGill University in Canada and his colleagues analysed data from 5600 global river flow measurement stations. Next, they used machine learning to predict the probability of intermittent flows along the rest of the global river network, based on each section’s climate, soil, geology and other environmental factors.
为了找出有多少河流是间歇性流动的，加拿大麦吉尔大学的Messager和他的同事分析了全球5600个河流流量测量站的数据。接下来，他们利用机器学习，根据每个河段的气候、土壤、地质和其他环境因素，预测全球其余河网中间歇性流动的概率。
From this, they estimated that water ceases to flow for at least one day per year along up to 60 per cent of the world’s 64 million kilometres of mapped rivers and streams.
据此，他们估计，在世界上6400万公里已绘制地图的河流和溪流中，有60%的河流每年至少断流一天。
Even more rivers could start to run dry in the future as climate change drives more severe, frequent droughts in some regions, says Ton Snelder at LWP, a water management consulting firm in New Zealand, who co-authored the study.
该研究的合著者、新西兰水资源管理咨询公司LWP的Snelder说，随着气候变化在一些地区导致更严重、更频繁的干旱，未来可能会有更多的河流开始干涸。
This could be exacerbated by disagreements over how to allocate river water, he says. “There are conflicting values about how to use water resources in pretty much every country in the world,” he says.
他说，在如何分配河水方面的分歧可能会加剧这种情况。“在世界上几乎每个国家，关于如何使用水资源的价值观都存在冲突。”
At the same time, global warming may cause some naturally intermittent rivers to start flowing continuously. For example, rivers in usually cold climates may freeze over less, says Snelder.
与此同时，全球变暖可能会导致一些自然间歇的河流开始持续流动。例如，通常在寒冷气候带的河流结冰的面积变小了，Snelder说。
These changes to river systems could affect biodiversity, he says. “The balance may shift in favour of some species and push others to local extinction.”
他说，这些河流系统的变化可能会影响生物多样性。“平衡可能会向有利于某些物种的方向转变，而将其他物种推向局部灭绝。”
More rivers drying up could also make it harder for some communities to access enough water for drinking, farming and other important uses, says Snelder.
斯纳尔德说，更多的河流干涸也可能使一些社区更难获得足够的饮用水、农业用水和其他重要用途所需的水。
The researchers hope the study will allow changes to river flows to be better monitored in the future and improve regulation of rivers, for instance by avoiding taking too much water from rivers with intermittent flows.
研究人员希望这项研究能在未来更好地监测河流流量的变化，并改善河流的管理，例如避免从断断续续的河流中抽取过多的水。