歷史中東:新月沃土,富饒不再

THE Middle East is arid. But it is also home to some of the world’s most fertile rivers, such as the Nile. So it is all the more alarming that one of its great river basins, the Tigris-Euphrates—which flows through the so-called fertile crescent that gave birth to agriculture itself—is getting drier. According to a study in Water Resources Research, an American scientific journal, between 2003 and 2009 the region that stretches from eastern Turkey to western Iran lost 144 cubic kilometres of fresh water.

中東地區氣候乾旱、土地貧瘠，但世界上孕育沃土的幾大河流均發源於此，尼羅河就是其中之一。“底格里斯河—幼發拉底河”流域屬世界之最，其河水流經“新月沃土”——昔日當地的農業發源地。如今兩河卻日漸枯竭，讓人格外憂心。據美國科學期刊《水資源研究》的一項研究顯示，2003至2009年間，土耳其東部至伊朗西部地區共失去了144立方千米的淡水。

That figure is vast. It is equivalent in volume to the Dead Sea and, according to the study’s senior author, Jay Famiglietti of the University of California, Irvine, implies that the region is suffering the world’s second-fastest rate of water depletion after northern India. The water table sank by 0.3 metres (one foot) a year in 2006-09. At the point where the Euphrates crosses from Syria into Iraq, it now flows at only 70% of the rate it once did. All this in an area that already faces severe water shortages.

這相當於一個死海的容量，數字十分龐大。據該研究的指導作者——加州大學歐文分校的簡?費米格利提（Jay Famiglietti）所示，如今該地區的水資源耗竭速度僅次於印度北部地區，爲世界第二。2006至2009年間，地下水位每年降低0.3米（1英尺）。在敘利亞、伊拉克邊境處的幼發拉底河，水流速度僅爲過去的70%。該地區的水資源本來就嚴重短缺，如今更是雪上加霜。

The study provides the first accurate estimate of all the water in the basin. National statistics are flawed and incomplete; some figures are even state secrets. But the study uses satellite data from America’s NASA which is not subject to these restrictions. These satellites not only measure surface water by photographs but, thanks to precise measurements of the effect of bodies of water on the atmosphere, can even calculate the amount of water in the aquifer below them.

該研究首次爲兩河流域的所有河流提供了一份準確的評估。各國國家統計局的數據並不準確，而且還不完整；有些數據甚至屬於國家機密。但該研究使用的是美國國家宇航局（NASA）發來的衛星數據，所以並不會受到這些限制的影響。那些衛星不僅可以通過照片測量地表水的容量，甚至還可以計算出地下的蓄水層所含水量，因爲衛星能夠精準地測量水體對大氣的影響。

The main reason for the depletion turns out to be that more water is being taken out of the underground aquifer, mainly by farmers. The rate of loss accelerated after drought hit the region in 2007. Between 2007 and 2009, in response to reduced flows of water in the rivers, Iraq’s government dug 1,000 new wells and abstracted four-fifths of all its groundwater reserves. The aquifer is not being replenished at anything like that rate, so this cannot continue for long.

原來，水資源之所以耗竭，主要是因爲人們（主要是農民）從地下蓄水層抽出的水過多。2007年該地區遭遇了旱災，因而水資源流失速度加快。在2007至2009年間，由於河流的水量減少，伊拉克政府新挖了1000口井，境內4/5的地下水資源都被抽乾。水資源消耗速度如此之快，蓄水層卻一直無法恢復到正常水量。所以這種狀況也持續不了多久。

The rapid depletion has implications for managing the basin, which is shared by Turkey, Syria, Iraq and Iran. All the countries have extensive dams, reservoirs and other sorts of infrastructure on both rivers which control the water’s flow. But they have no international treaty governing when and by how much they can shut the flow down.

水資源的迅速枯竭爲兩河流域的治理帶來了一定啓示。該地區爲土耳其、敘利亞、伊拉克和伊朗共有，所有國家都在兩河上建了大量水壩、水庫和其他基礎設施，對水流進行控制。但他們並沒有達成國際條約，約定應何時阻截水流、以及阻截多少。

Over the years, this has not mattered much. The countries have rubbed along, sometimes amicably, sometimes not, with downstream ones (notably Syria and Iraq) assuming there would always be enough water in the upstream reservoirs of Turkey for them all. But if the new study is any guide, that assumption may not hold for much longer. As Mr Famiglietti says, “The region is ripe for collaborating on the science of water management. Whether it is ready for an international legal framework, I have no idea.”

多年來，這並沒有造成很大影響。國家之間也算相安無事，有時相處融洽，有時也不盡然，因爲下游區域的國家（尤其是敘利亞和伊拉克）總認爲土耳其在上游區域的水庫能爲他們提供充沛的水資源。但如果這份新研究有可借鑑之處，那樣的說法可能就撐不了多久了。正如費米格利提所說，“兩河流域地區是該共同合作、科學管理水資源了。不過，我不清楚它是否願意接受國際法律框架的束縛。”