2月24日,，美國(guó)《科學(xué)》雜志刊登的一篇研究報(bào)告顯示,，曾在墨西哥尤卡坦半島和中美洲興盛一時(shí)的瑪雅文明的崩潰，可能與中等程度的干旱有關(guān),。
科學(xué)界長(zhǎng)期以來(lái)一直懷疑,，瑪雅人歷時(shí)100多年的緩慢衰敗與周期性的干旱有關(guān)，但未能確認(rèn)瑪雅社會(huì)在崩潰前經(jīng)歷了多大程度的干旱,。墨西哥尤卡坦科研中心和英國(guó)南安普頓大學(xué)研究人員分析了來(lái)自尤卡坦半島的湖泊和石筍記錄后發(fā)現(xiàn),，在公元800年至950年間的瑪雅文明衰敗期，由于夏季風(fēng)暴減少,，該地區(qū)降雨量曾不時(shí)地減少,，有些降雨量減少的時(shí)期可長(zhǎng)達(dá)10年，總體而言,，瑪雅社會(huì)經(jīng)歷的年度降水量比此前的正常期少大約25％至40％,。這使該地區(qū)河流、湖泊等“開(kāi)放水源”的蒸發(fā)量超過(guò)降水量,。
研究人員表示,，夏季是瑪雅人耕作并對(duì)貯水系統(tǒng)進(jìn)行補(bǔ)充的主要季節(jié)，而中等程度的降水減少就導(dǎo)致部分沒(méi)有河流或其他水源的地區(qū)經(jīng)歷比較嚴(yán)重的水荒,，“社會(huì)解體,、城市被拋棄就成為水荒的可能后果，特別是因?yàn)槌掷m(xù)多年的干旱頻繁發(fā)生”,。
研究人員表示,，這項(xiàng)發(fā)現(xiàn)凸顯了尤卡坦半島和中美洲對(duì)中度干旱情況的敏感性，這對(duì)現(xiàn)代社會(huì)也具有警示意義——即便現(xiàn)代人擁有更先進(jìn)的抗旱手段,，降水量的持續(xù)減少也可能產(chǎn)生深遠(yuǎn)影響,。
doi: 10.1126/science.1216629
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Collapse of Classic Maya Civilization Related to Modest Reduction in Precipitation
Martín Medina-Elizalde, Eelco J. Rohling.
The disintegration of the Classic Maya civilization in the Yucatán Peninsula and Central America was a complex process that occurred over an approximately 200-year interval and involved a catastrophic depopulation of the region. Although it is well established that the civilization collapse coincided with widespread episodes of drought, their nature and severity remain enigmatic. We present a quantitative analysis that offers a coherent interpretation of four of the most detailed paleoclimate records of the event. We conclude that the droughts occurring during the disintegration of the Maya civilization represented up to a 40% reduction in annual precipitation, probably due to a reduction in summer season tropical storm frequency and intensity.
