New research sheds light on the disappearance of an ancient society

新研究揭示了一个古文明社会的消失

A The Harappan Civilisation of ancient Pakistan and India flourished 5,000 years ago, but a thousand years later their cities were abandoned. The Harappan Civilisation was a sophisticated Bronze Age society who built 'megacities' and traded internationally in luxury craft products, and yet seemed to have left almost no depictions of themselves. But their lack of self-imagery - at a time when the Egyptians were carving and painting representations of themselves all over their temples - is only part of the mystery.

A 古巴基斯坦和印度的哈拉帕文明在五千年前非常繁荣，但是一千年后这里的城市便被废弃。哈拉帕文明曾是一个精细复杂的青铜时代社会，他们建造了许多“大型城市”并进行奢华工艺品的国际贸易，但似乎关于他们自身的描述几乎都没有留下，但是哈拉帕文明自身形象的缺失——在一个埃及人已经在庙宇中到处雕刻和绘制自身象征的时代——只是这个谜题的一部分。

B 'There is plenty of archaeological evidence to tell us about the rise of the Harappan Civilisation, but relatively little about its fall,' explains archaeologist Dr Cameron Petrie of the University of Cambridge. 'As populations increased, cities were built that had great baths, craft workshops, palaces and halls laid out in distinct sectors. Houses were arranged in blocks, with wide main streets and narrow alleyways, and many had their own wells and drainage systems. It was very much a "thriving" civilisation.' Then around 2100 BC, a transformation began. Streets went uncleaned, buildings started to be abandoned, and ritual structures fell out of use. After their final demise, a millennium passed before really large-scale cities appeared once more in South Asia.

B “有许多考古学证据可以告诉我们有关哈拉帕文明的崛起，但相比之下没有什么关于其没落的证据”，剑桥大学考古学家 Cameron Petrie博士解释道。“随着人口增加，他们建立了在不同区域分布着大型浴场、工艺品工厂、宫殿和会堂的城市。房屋按照街区布置，有宽敞的大街和狭窄的卷子，很多有自己的水井和排水系统。这在很大程度上是一个‘发展兴旺’的文明。”在公元前2100年左右，变化开始发生。街道不再清洁，建筑物开始被遗弃，仪式建筑也被废止使用。在它们最终衰落之后，过了一千多年真正的大型城市才再一次在亚洲南部出现。

C Some have claimed that major glacier-fed rivers changed their course, dramatically affecting the water supply and agriculture; or that the cities could not cope with an increasing population, they exhausted their resource base, the trading economy broke down or they succumbed to invasion and conflict; and yet others that climate change caused an environmental change that affected food and water provision. 'It is unlikely that there was a single cause for the decline of the civilisation. But the fact is, until now, we have had little solid evidence from the area for most of the key elements,' said Petrie. 'A lot of the archaeological debate has really only been well- argued speculation.'

C 有些人认为巨大的冰川河流改变了线路，对供水和农业产生了显著影响；或者城市无法应对增长的人口，资源被消耗殆尽，贸易经济体系受到破坏。或者它们毁于侵略和冲突；而有些人认为气候变化导致了环境变化，这种变化影响了食物和水资源供应。“不太可能是单一的因素导致了一种文明的衰亡，但事实是，迄今为止，我们在这一地区对一些关键要素没有什么确凿证据”， Petrie说。“许多考古学的辩论只是一些论证充分的推断。

D A research team led by Petrie, together with Dr Ravindanath Singh of Banaras Hindu University in India, found early in their investigations that many of the archaeological sites were not where they were supposed to be, completely altering understanding of the way that this region was inhabited in the past. When they carried out a survey of how the larger area was settled in relation to sources of water, they found inaccuracies in the published geographic locations of ancient settlements ranging from several hundred metres to many kilometres. They realised that any attempts to use the existing data were likely to be fundamentally flawed. Over the course of several seasons of fieldwork they carried out new surveys, finding an astonishing 198 settlement sites that were previously unknown.

D 一个由 Petrie带领的研究团队，与贝拿勒斯印度教大学的 Ravindanath Singh博士一起，在他们调查的早期发现许多考古学遗址并不位于人们假设的地方，这完全改变了人们过去对于这一区域位置的理解。当他们调查完更大地区的位置与水资源的关系，他们发现已发布的古老定居地点的地理位置存在看从几百米到几公里不等的误差。他们意识到使用现有数据进行的任何尝试可能从根本上就是存在缺陷的。经过几个季度的野外考察，他们完成了新的报告，发现了198个之前并不为之所知的定居位置，这非常令人惊讶。

E Now, research published by Dr Yama Dixit and Professor David Hodell, both from Cambridge's Department of Earth Sciences, has provided the first definitive evidence for climate change affecting the plains of north-western India, where hundreds of Harappan sites are known to have been situated. The researchers gathered shells of Melanoides tuberculata snails from the sediments of an ancient lake and used geochemical analysis as a means of tracing the climate history of the region. 'As today, the major source of water into the lake is likely to have been the summer monsoon,' says Dixit. 'But we have observed that there was an abrupt change about 4,100 years ago, when the amount of evaporation from the lake exceeded the rainfall - indicative of a drought.' Hodell adds: 'We estimate that the weakening of the Indian summer monsoon climate lasted about 200 years before recovering to the previous conditions, which we still see today.'

E 如今，来自剑桥大学地球科学系的 Yama Dixit博士和 David Hodell教授发表的研究提供了第一个真凭实据，说明了气候变化对印度西北部平原的影响，而数百个哈拉帕定居点就位于这里。研究者们在一个古代湖泊的沉积物中发现了瘤拟黑螺的贝壳，并使用地球化学分析作为追测该地区气候历史的方法。“像今天一样，湖的中的水或许主要来自夏季季风”，Dixit说。“但是我们观测到大约4100年前发生了突然的变化，当时湖泊的蒸发量超过了降雨量，这预示着干早的发生。" Hodell补充道:“我们估计印度夏季季风气候的减弱持续了大约200年，之后才恢复成我们如今依然能够看那种环境。

F It has long been thought that other great Bronze Age civilisations also declined at a similar time, with a global-scale climate event being seen as the cause. While it is possible that these local-scale processes were linked, the real archaeological interest lies in understanding the impact of these larger-scale events on different environments and different populations. 'Considering the vast area of the Harappan Civilisation with its variable weather systems,' explains Singh, 'it is essential that we obtain more climate data from areas close to the two great cities at Mohenjodaro and Harappa and also from the Indian Punjab.'

F 长久以来人们认为其他伟大的青铜时期文明也在相似的时间衰亡，并将全球范围的气候事件视为其衰亡的原因。尽管这些地区规模性的事件或许存在联系，真正的考古兴趣在于理解这些全球范围的事对不同环境和不同人群的影响。“考虑到哈拉帕文明的广大地域以及多变的天气系统，" Singh解释道，“我们在摩亭佐达罗和哈拉帕这两座大型城市以及印度旁遮普周围的地区得到更多气候数据是丰常重要的。''

G Petrie and Singh's team is now examining archaeological records and trying to understand details of how people led their lives in the region five millennia ago. They are analysing grains cultivated at the time, and trying to work out whether they were grown under extreme conditions of water stress, and whether they were adjusting the combinations of crops they were growing for different weather systems. They are also looking at whether the types of pottery used, and other aspects of their material culture, were distinctive to specific regions or were more similar across larger areas. This gives us insight into the types of interactive networks that the population was involved in, and whether those changed.

G Petrie和Singh的团队如今正在调查考古记录并试图细致了解人们五千年前是如何在这里生活的。他们分析当时培育的谷物，并试图发现它们是否种植在极端的水压环境下，以及人们是否根据不同的天气系统调整种植谷物的组合方式。他们同样关注人们使用的陶器种类，以及他们物质文化的其他方面，是特定区域独有的还是在更大的区域内类似的。这使得我们深入了解人们的交互模式，以及是否发生过变化。

H Petrie believes that archaeologists are in a unique position to investigate how past societies responded to environmental and climatic change. 'By investigating responses to environmental pressures and threats, we can learn from the past to engage with the public, and the relevant governmental and administrative bodies, to be more proactive in issues such as the management and administration of water supply, the balance of urban and rural development, and the importance of preserving cultural heritage in the future.'

H Petrie相信考古学家在调查过去社会如何应对环境和气候变化方面处在独一无二的位置。“通过调查对环境压力和威胁的应对方式，我们可以向过去的人们学习。从而与公众和相关的政府及行政机关进行沟通，使他们将来在一些问题的处理上更有前瞻性，比如水资源的管理、城乡发展的平衡，以及文化遗产保护的重要性。”