by Nicholas Mott

Every civilization has its rise and fall. But no culture has fallen quite like the Maya Empire, seemingly swallowed by the jungle after centuries of urban, cultural, intellectual, and agricultural evolution.

What went wrong? The latest discoveries point not to a massive eruption[爆發(fā)], quake, or plague[瘟疫] but rather to climate change. And faced with the fallout[附帶結(jié)果], one expert says, the Maya may have packed up and gone to the beach.

But first came the boom[繁榮] years, roughly A.D. 300 to 660. At the beginning of the so-called Classic Maya period, some 60 Maya cities—each home to between 60,000 and 70,000 people—sprang up[萌芽，出現(xiàn)] across much of modern-day Guatemala, Belize, and Mexicos Yucatán Peninsula[半島].

Surrounded by pyramids, plazas, ball courts[球場(chǎng)], and government buildings, the urban Maya discussed philosophy, developed an accurate solar-year calendar, and relished[品味] the worlds first hot chocolate.

Farmers, too, were riding high, turning hillsides into terraced[使成梯形地] fields to feed the growing population.

Then came the bust[蕭條時(shí)期], a decline[衰落] that lasted at least two centuries. By 1100 the residents[居民] of once thriving[繁榮的] Maya cities seem to have just packed up and left. But where did they go, and why?

In the 19th century, when explorers began discovering the ruins of “l(fā)ost cities,” people imagined an large volcanic eruption or earthquake or superstorm—or maybe a pandemic[流行性疾病].

But today, scientists generally agree that the Maya collapse[崩潰] has many roots—overpopulation, warfare, famine[饑荒], drought[干旱]. At the moment, the hottest discussion centers on climate change, perhaps of the Mayas own doing.

Flowering[發(fā)展，興旺] with the Rain

The latest Maya climate-change study, published in the journal Science, analyzes[分析] a Belizean caverns[洞窟] stalagmites[石筍] to link climate swings[擺動(dòng)] to both the rise and fall of the empire.

Formed by water and minerals dripping from above, stalagmites grow quicker in rainier years, giving scientists a reliable[可信賴(lài)的] record of historical precipitation[沉淀；降雨量] trends.

Among the trends revealed by the Belizean stalagmites: “The early Classic Maya period was unusually wet, wetter than the previous thousand years,” according to study leader Douglas Kennett, an environmental anthropologist[人類(lèi)學(xué)家] at Pennsylvania State University. “During this time, the population proliferated[激增],” aided by a growth in agriculture.

During the wettest decades, from 440 to 660, cities grew very quickly. All the hallmarks[標(biāo)記，特點(diǎn)] of Maya civilization—clever political systems, monumental[紀(jì)念碑的] architecture[建筑], complex religion—came into full flower during this era.

Climate Shift Causes Conflict[沖突]

But the 200-year-long wet spell[一段時(shí)間] turned out to be a one-off. When the climate pendulum[鐘擺] swung back, hard times followed.

“Mayan systems were founded on those [high] rainfall patterns, ” Kennett said. “They could not support themselves when patterns changed.”

The following centuries, from about 660 to 1000, were characterized by repeated and, at times extreme, drought. Agriculture declined and social conflict rose, Kennet says.

The Maya religious and political system was based on the belief that rulers were in direct communication[交流] with the gods. When these connections failed to produce rainfall and good harvests, tensions likely developed.

But times would get even harder.

The stalagmite record suggests that between 1020 and 1100, the region suffered its longest dry spell of the last 2,000 years. With it, the study suggests, came Maya crop failure, famine, mass migration[移民], and death.

By the time Spanish conquistadors注 arrived in the 16th century, inland Maya populations had decreased by 90 percent, and urban centers had been largely abandoned[放棄]. Farms had become overgrown[簇葉叢生的] and cities reclaimed[收回] by forest.

A Cautionary[警戒的] Tale?

The collapse, though, wasnt exactly all natural. To some extent[某種程度上], the Maya may have designed their own decline.

“There were tens of millions of people in the area, and they were building cities and farms at the expense of[在損害……的情況下] the forest,” climate scientist Benjamin I. Cook said.

注：尤指16世紀(jì)入侵墨西哥、中美洲或秘魯印第安的西班牙士兵。

Widespread deforestation[采伐森林] reduced the flow of moisture from the ground to the atmosphere[大氣], interrupting the natural rain cycle and in turn reducing precipitation, says Cook, of NASAs Goddard Institute for Space Studies and the Lamont-Doherty Earth Observatory[觀(guān)測(cè)所].

This could be a cautionary tale for modern society, according to Cook. Today, as more and more forestland is turned into farms and cities, and as global temperatures continue to rise, we may risk the same fate that befell the Maya, he says.

But, according to Arizona State University professor of environment and society B.L. Turner, “the Mayan situation is not applicable[可適用的] today—our society is just so different now.”

In a study published in last August by the journal Proceedings[（科學(xué)文獻(xiàn)）匯編] of the National Academy of Sciences, Turner attempts to correct some common misconceptions, beginning with the idea that Maya civilization vanished[消失] after the conquistadores arrived.

“It didnt cease[停止] to exist; there are still today Mayan people in the area. The culture, the traditions have been maintained,” he said. But the cities, historically, have not—and thats odd.

Throughout global history, he said, “rarely can you find a large population that just left and never came back,” Turner said.

Turners study concludes that the natural environment recovered rather quickly after the dry centuries. Why, then, didnt the Maya reclaim their cities?

Turner points to the coasts. Fleeing[逃走] starving, warring inland cities, many Maya went for the shore. Trade also shifted, from overland[陸路的] paths to coastal routes, he suggests.

With life relatively[相對(duì)地] comfortable on the coast, the inland Mayan cities may have simply been forgotten, Turner says. No terrible earthquake, no plague, no curse, but rather a gradual migration to the beach, where life was a bit more comfortable.

That is, until the Spanish arrived.

每個(gè)文明都有自己的興衰，但沒(méi)有哪個(gè)文明像瑪雅帝國(guó)一樣，在經(jīng)過(guò)數(shù)百年的城市、文化、智慧和農(nóng)業(yè)發(fā)展之后，竟然像被叢林吞沒(méi)一樣消失得無(wú)影無(wú)蹤。

問(wèn)題出在哪里？最新的發(fā)現(xiàn)顯示，原因不是大型的火山爆發(fā)、地震或瘟疫，而是氣候變化。一位專(zhuān)家稱(chēng)，面對(duì)氣候變化的影響，瑪雅人可能收拾行裝，向海灘進(jìn)發(fā)。

讓我們先回到大約公元300至660年，也就是瑪雅文明的繁榮時(shí)期。在所謂的“古典期”之初，該地區(qū)興起了大約六十座瑪雅城市，散布于今天的危地馬拉、伯利茲以及墨西哥的尤卡坦半島等地，每座城市約有六至七萬(wàn)人口。

這些瑪雅城市周?chē)h(huán)繞著金字塔、廣場(chǎng)、球場(chǎng)和政府大樓；城里的瑪雅人探討著哲學(xué)，發(fā)明了精確的太陽(yáng)歷，品嘗著世界上最早的熱巧克力。

農(nóng)民也向高處遷移，把山坡開(kāi)墾成梯田，以養(yǎng)活不斷增長(zhǎng)的人口。

隨后瑪雅文明走向蕭條，在至少兩個(gè)世紀(jì)的時(shí)間里持續(xù)衰退。到了1100年，一度繁華的瑪雅城市中的居民似乎全都卷起鋪蓋，棄城而去。他們?nèi)チ四睦锬?？又是出于什么原因?/p>

19世紀(jì)，當(dāng)探險(xiǎn)家開(kāi)始探索這些“失落之城”的遺址時(shí)，人們?cè)O(shè)想這里可能發(fā)生過(guò)一場(chǎng)大型的火山爆發(fā)、地震、超級(jí)風(fēng)暴，或者是瘟疫。

然而今天，科學(xué)家們普遍同意瑪雅文明的衰落有多方面的原因，比如人口過(guò)多、戰(zhàn)爭(zhēng)、饑荒和干旱等等。目前最熱門(mén)的討論焦點(diǎn)是氣候變化，而這或許是瑪雅人咎由自取的結(jié)果。

與雨水共繁榮

發(fā)表在《科學(xué)》期刊上有關(guān)瑪雅氣候變化的最新研究對(duì)伯利茲一處洞穴的石筍進(jìn)行了分析，從而把氣候變化與瑪雅帝國(guó)的興衰聯(lián)系在了一起。

石筍由洞穴頂部滴落的水和礦物質(zhì)形成。在多雨的年份，石筍生長(zhǎng)的速度會(huì)更快。這給科學(xué)家提供了一份關(guān)于沉淀物變化趨勢(shì)的可靠歷史記錄。

在伯利茲石筍透露出來(lái)的變化趨勢(shì)當(dāng)中，“古典瑪雅時(shí)期的早期，氣候異常潮濕，比那以前的一千年更加潮濕。”該研究負(fù)責(zé)人——（美國(guó)）賓夕法尼亞州立大學(xué)環(huán)境人類(lèi)學(xué)家道格拉斯·肯尼特說(shuō)，得益于農(nóng)業(yè)的增長(zhǎng)，“在這段時(shí)間內(nèi)，人口大量繁殖”。

公元440年至660年這最潮濕的幾十年間，城市以極快的速度發(fā)展?，斞盼拿鞯囊磺袠?biāo)志，如巧妙的政治制度、紀(jì)念碑般的建筑和復(fù)雜的宗教等，都在這個(gè)時(shí)期走向全面繁榮。

氣候變化引發(fā)沖突

然而，持續(xù)200年的雨水期此后一去不返。當(dāng)氣候的鐘擺往回?cái)[動(dòng)，艱難的日子也隨之而至。

“瑪雅的各種制度都是以（高）降雨量模式為基礎(chǔ)建立的，”肯尼特說(shuō)?！爱?dāng)這種模式發(fā)生改變，他們便無(wú)法自給自足?！?/p>

肯尼特說(shuō)，在接下來(lái)從約公元660年至1000年的幾百年間，瑪雅文明經(jīng)歷了反復(fù)的干旱，有時(shí)甚至是極度干旱。農(nóng)業(yè)衰退，社會(huì)矛盾上升。

瑪雅人相信統(tǒng)治者能直接與神明溝通，這也是瑪雅宗教和政治制度的根基。當(dāng)這種聯(lián)系無(wú)法帶來(lái)降雨和豐收，就可能引發(fā)沖突。

然而，前面的光景更加艱難。

石筍記錄表明，從公元1 0 2 0年到1100年，該地區(qū)遭遇了過(guò)去2 0 0 0年來(lái)持續(xù)時(shí)間最長(zhǎng)的旱災(zāi)。研究顯示，這場(chǎng)旱災(zāi)導(dǎo)致瑪雅糧食歉收，引發(fā)饑荒、大遷徙和死亡。

到16世紀(jì)西班牙征服者到達(dá)這里時(shí)，內(nèi)陸的瑪雅人口已經(jīng)減少了90%，大部分城市中心已被遺棄。農(nóng)田雜草叢生，城市重新被森林占領(lǐng)。

警世寓言？

不過(guò)，瑪雅文明的衰敗并不能完全歸咎于自然原因。在一定程度上，瑪雅人的衰敗可能是咎由自取。

氣候?qū)W家本杰明·I·庫(kù)克說(shuō)：“該地區(qū)有數(shù)以千萬(wàn)計(jì)的人口，他們?yōu)榱私ㄔ斐鞘泻娃r(nóng)場(chǎng)不惜砍伐森林?！?/p>

庫(kù)克任職于美國(guó)國(guó)家航空航天局（NASA）的戈達(dá)德太空研究所和拉蒙特-多哈提地球觀(guān)測(cè)站。他說(shuō)，大面積的森林砍伐令從地面升上大氣的水分減少，阻斷了自然降水循環(huán)，從而令降雨量減少。

根據(jù)庫(kù)克的說(shuō)法，這或許可以作為現(xiàn)代社會(huì)的警世寓言。如今，越來(lái)越多的林地被改造成農(nóng)場(chǎng)和城市，而隨著全球氣溫的不斷上升，我們可能面臨著曾經(jīng)降臨到瑪雅人身上的同樣命運(yùn)。

不過(guò)，（美國(guó)）亞利桑那州立大學(xué)環(huán)境與社會(huì)教授B·L·特納說(shuō)：“瑪雅的情況并不適用于今天——我們現(xiàn)今的社會(huì)與他們已經(jīng)大為不同了?！?/p>

海岸的魅力

在其去年8月發(fā)表在《美國(guó)國(guó)家科學(xué)院院刊》的一份研究報(bào)告中，特納試圖糾正一些常見(jiàn)的誤解。首先一個(gè)誤解，就是認(rèn)為瑪雅文明是在西班牙征服者到達(dá)之后消失的。

“瑪雅文明并沒(méi)有消失，今天在這個(gè)地區(qū)依然有瑪雅人，他們的文化和傳統(tǒng)保留了下來(lái)，”他說(shuō)。然而歷史上的瑪雅城市卻沒(méi)有保存下來(lái)，這一點(diǎn)很不尋常。

他說(shuō)，縱觀(guān)全球歷史，“你很難找到大量人口一去不返的例子”。

特納的研究結(jié)論認(rèn)為，在經(jīng)歷數(shù)百年的干旱之后，自然環(huán)境迅速恢復(fù)。那么瑪雅人為什么沒(méi)有奪回他們的城市呢？

特納轉(zhuǎn)向了海岸。許多瑪雅人從被饑餓與戰(zhàn)爭(zhēng)蹂躪的內(nèi)陸城市逃往沿海地區(qū)。他說(shuō)，瑪雅人所從事的貿(mào)易也發(fā)生了變化，從陸路變成了海路。

特納認(rèn)為，瑪雅人生活在相對(duì)舒適的海岸，可能就把內(nèi)陸的城市給忘了?，斞懦鞘兄员贿z棄，既不是因?yàn)榭膳碌牡卣?，也不是因?yàn)槲烈呋蛘咴{咒，而是因?yàn)樗麄冎鸩竭w徙到了生活更為舒適的海灘。

——直到西班牙人的到來(lái)。