, 刘倩, 陈鑫鑫Spatial-temporal evolution of early history of north China (1600 BC-300 AD) and dynastic cycle driven by climate change
CHENSha, LIUQian, CHENXinxin通讯作者:
收稿日期:2016-07-22
修回日期:2017-06-7
网络出版日期:2017-09-30
版权声明:2017《地理学报》编辑部本文是开放获取期刊文献，在以下情况下可以自由使用：学术研究、学术交流、科研教学等，但不允许用于商业目的.
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1 引言
对于气候变化与中国历史演化之间关系,尽管争议颇多,大致还是取得了如下共识：气候适宜期（暖湿期）：经济繁荣、民族统一、社会稳定、国家强盛;气候恶化期（冷干期）：经济衰退、灾害频发、饥民流民增多、政局动荡、游牧民族南侵、战争高发、国家分裂、社会政治经济文化重心南移,区域人类社会面临严重的生存危机[1-8]。这就是说,气候环境变化对中国社会历史演化具有重要影响[9]。这种以朝代更迭为特征的中国历史,在中晚全新世的气候演化背景之上,在以中原地区为中心的中国北方多次重演,构成了中国历史特有的以治—乱为主题的旋回式演化模式[10-11]。历史学家Toynbee 1972年曾把这种社会历史结构,称为中国模式,并认为这种模式适用于各文明发展的晚期阶段,从而认定这种模式是一种纯粹的社会发展模式[10]。
在解释这种模式的内在机制时,历史学家们注意到了伴随着社会历史发展旋回的是政权腐败、贫富差距和政府官员道德的循环以及人口、司法约束、政府规模的循环、自耕农递减特征与公共财政的短缺循环等社会问题[11-14]。这就是说,在解释中国社会历史演化时,全球变化研究的视角认为气候环境变化对社会历史进程产生了重大影响,但还没有拿出令人信服的非统计式的证据;历史学家则更认同社会的演替需要从社会历史演化内部寻找原因这一逻辑,对气候环境能导致社会历史的演替的认同还有待深化。
这一方面,是因为在将高分辨率地质记录与社会历史演替的具体过程联系在一起[7]时,出现过诸多无法一致甚至相反的情况[15];指示了气候变化与中国社会历史进程之间的关系也并非如上所说的那样简单。另一方面,从新石器时代中晚期仰韶文化阶段到中国社会历史时期演化的整个时段,现在的农牧交错带年降水为300~400 mm的中国北方的温度变化也仅有2~4 ℃、年降水变化幅度最大也不超过200 mm[16-19]。也就是说,即使是在极端恶劣的气候期,祖先生存的亚洲东部大部分地区,环境也从未恶劣到绝对无以生存的境地。因此,气候变化对中国社会历史演化的影响,或者说气候变化对中国的朝代更替的作用,从来不是简单的毁灭,而是一个治—乱—治的演化旋回,涉及到方方面面的因素,需要从多学科多角度相互联系的视角才能获得更客观更深刻的认识。
大量的证据证实气候变化确实能对人类与人类社会产生重大影响[20-23],在多数情况下,均涉及到灾难、疾病、人口、经济变化、环境适应甚至社会管理等一系列自然—经济—人文系统等方面的众多因素[24-29]的反馈作用。Webster 1975年曾提出在资源有限和人口增长情况下,战争是一种生态性适应的观点[24]。葛全胜等[9]借用国际科联环境问题科学委员会（SCOPE）的观点,认为气候变化对中国社会的影响,沿自然—经济—人文子系统的各个环节而逐级传导,具有多个层次的冲击与社会的适应,指示中国社会对环境恶化同样存在积极的反馈作用。但这种对气候环境变化的自组织适应性是否具有普遍性,对中国社会历史影响如何?这是研究中国社会历史发展与气候变化关系的关键,随着全球变化的深化,这些问题需要密切联系中国社会历史人文系统的诸多特点深入探讨,但目前这方面的研究尚比较少见。
本文基于气候代用指标记录的气候环境的演化过程与中国早期社会历史进程的对比,从地理环境、气候变化的角度,沿着环境—农业—人口—社会体制这个链条,从某一历史时段的个案研究出发,尝试分析东亚季风区环境与气候变化影响社会历史演化的途径与方式。选择中国历史早期这个时段来研究,主要是考虑到这是中国历史上气候变化幅度最大的时期,是考察气候变化对社会历史演化的最佳时段;另外,历史早期社会政治结构和社会经济结构相对简单,所涉及的因素较少,易于展开相关研究。
2 代用指标揭示的中国北方早期历史时期气候环境变化特点
气候与环境的代用指标记录,主要来自于内蒙古黄旗海H6剖面。此剖面年代框架精度高,分辨率较高（平均约25年/样品）,代用指标（粒度、元素和孢粉）的环境指示意义较为明确[30-31]。考虑到单一记录区域代表性不足的弱点,将其与内蒙古岱海[32-33]、黄土高原中西部六盘山天池[34]湖泊沉积、贵州董哥洞石笋氧同位素[35]、广东湛江的湖光玛珥湖[36]等记录进行了对比,以考察H6记录的代表性。各记录的地理位置如图1所示。
显示原图|下载原图ZIP|生成PPT图1黄旗海区域位置及本文所涉及的几个记录的地理位置示意图
-->Fig. 1Geographical location of Huangqi Lake basin and the records used in this paper
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H6剖面为全新世黄旗海湖泊萎缩过程中河流下蚀而在现代湖泊一级阶地的前缘形成的天然剖面。剖面总厚310 cm,本文所涉及的部分,层厚130 cm,包括3种沉积相（图2）：滨湖相（深295~305 cm）、深湖相（深240~295 cm）、浅湖相（深170~240 cm）。以1.5 cm间隔对剖面进行系统采样,进行了粒度、元素地球化学和孢粉分析[30-31]。在不同深度（主要在沉积相变化界线附近）分取4个样品,提取碳屑与孢粉[30],进行AMS14C年代分析,样品在美国迈阿密BETA实验室测试。
年代结果表明（图2）,本文所涉及的H6剖面湖相沉积时代为3580-1800 cal a BP（日历年,为了与历史记录对比,本文将0 cal a BP视为2010年而不是传统的1950年,这样基本与公元纪年保持同步,方便阅读与理解）。根据沉积相及代用指标的变化特点,H6剖面所反映的晚全新世气候变化大致分为3580-3050 cal a BP、3050-1800 cal a BP两个时段。
显示原图|下载原图ZIP|生成PPT图2黄旗海H6剖面地球化学元素和风化指数记录的3600-1800 cal a BP时段气候环境变化
-->Fig. 2Climate change during 3600-1800 cal a BP recorded by geochemical elements, weathering index and other proxies from H6 section in Huangqi Lake basin
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3580-3050 cal a BP时期,沉积相与粒度揭示,H6剖面位置为深湖湖泊环境,沉积颗粒较细,粉砂为主,指示水动力弱;古湖面高出现代湖面（1270 m,1976年水位）近20~25 m,达到1295~1300 m[30]。其时,剖面所在的水深约为19~24 m。孢粉分析出现了大量的盘星藻科的孢子（Pediastraceae）,证实黄旗海是个淡水广域湖泊。针叶树孢粉（Pinus）浓度最高,并出现了一些落叶树孢粉,推测流域出现以针叶林为主的针阔混交林[30]。元素地球化学指示流域化学风化淋溶较强（图2）。这些证据一致地指示了流域气候环境湿润,夏季风较强,流域有效降水高,湖泊扩涨。
3050-1800 cal a BP时期,沉积相指示黄旗海为浅湖湖泊环境;较上一阶段,粒度显著变粗,揭示随着水位下降,湖泊水深变浅,水动力变强。古湖面大致维持在1285~1290 m,显著萎缩[30]。阔叶树孢粉浓度降低并消失,针叶树孢粉浓度快速降低,蒿、黎等草本花粉浓度显著增加,指示了一个干燥气候的到来;并且,蒿/黎比值在这其间逐渐增加,指示气候具有越来越干燥的趋势[30]。推测针阔混交林消失,干草原出现并逐渐扩展。元素地球化学也指示逐渐减弱的化学风化状况（图2）。
这个时期大致又可分为6个亚期：① 3050-2930 cal a BP西周气候快速恶化期;② 2930-2700 cal a BP西周干燥期;③ 2700-2430 cal a BP春秋湿润期;④ 2430-2330 cal a BP战国干燥期;⑤ 2330-1980 cal a BP秦—西汉湿润期;⑥ 1980-1800 cal a BP东汉干燥期（图4）。
H6剖面指示的这种气候演化的特点,与南、北方众多高分辨率气候记录[32-36]及南方洞穴石笋[35]等在测年误差范围内存在较好的对比关系（图3）：黄旗海记录的气候干旱期,基本上对应董哥洞石笋氧同位素记录的夏季风强度减弱和湖光玛珥湖记录的冬季风强度增加相一致;并且与史料记载的气候环境变化[37-41]也极为吻合。夏末商初（3.6-3.5 cal ka BP）、商末（3.6-3.5 cal ka BP）、西周末年（2.8-2.7 cal ka BP）、战国（2.45-2.35 cal ka BP）和公元前后的诸多干旱事件[40-41],都在黄旗海的湖泊沉积中有清晰的记录。
显示原图|下载原图ZIP|生成PPT图3东亚季风区气候记录[
-->Fig. 3Comparison of the climate records[
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这种跨越不同纬度的气候代用指标的一致性及其与中原地区史料记载的一致性,揭示季风气候演化在数十年—百年尺度上的同步性。这意味着,黄旗海H6剖面气候记录不仅仅代表了本流域的气候演化,同时也能反映至少中国北方较广阔区域的环境变化,具有较强的代表性。
3 气候环境变化与北方早期社会历史时空演进
与气候环境的演化相对应,早期中国历史的演化,也大致经历了3580-3050 cal a BP、3050-1800 cal a BP前后两个阶段（图4）。不同的阶段,社会政治生态也具有不同的宏观格局。具体表现如下：（1）商代湿润期,这是全新世大暖期即将结束时的一个稳定湿润期,其续存时间与商王朝这个中国历史上延续时间最久的王朝的政治续存期高度吻合（按夏商周断代工程对商王朝的时间界定为（1600-1046 BC[42],相当于本文3610-3056 cal a BP）,社会政治生态单调。而在随后的从西周到东汉的干燥阶段,由奴隶社会过渡到封建社会,政治生态复杂多样,既有诸侯割据的混乱,也存在大一统的强盛王朝。从商—西周—东周—秦—西汉—东汉—三国,政权更迭频繁,说明政治生态压力大,各派政治势力之间的关系也较紧张,也说明中国社会历史进程显著提速。
（2）年代对比发现（图3）,商代夏、周代商、西周东迁、西汉与东汉的灭亡等社会政治事件,都发生在沉积记录所指示的气候环境的剧烈变化（恶化）期。
商代夏：商取代夏,夏商周断代工程（以下简称工程）（2000）证实为1600 BC,这与H6剖面指示3580±30 cal a BP之前的低湖面相吻合,指示商之前存在一个干燥的气候阶段。考古史料揭示原先居住于太行山麓的商人正是在这样的气候背景下南下的[43]。史料也记载这个干燥的气候期一直延续到商代早期：昔者汤克夏而正天下,天大旱,五年不收（吕氏春秋—顺民）;商凅旱,汤犹发师以信伊尹之盟（吕氏春秋—慎大览）。
周代商：周取代商,夏商周断代工程（2001）确定为1046 BC年。商代湿润期,从3150 cal a BP开始趋于干燥,3041±30 cal a BP年前后（相当于1031 BC年）开始了一个剧烈恶化阶段（图4）。
显示原图|下载原图ZIP|生成PPT图4H6剖面记录的环境演变与中国早期历史各王朝都城变迁[
-->Fig. 4Relationship between climate change recorded by H6 profile and the present precipitation of the capital cities of dynasties in early Chinese history
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平王东迁：历史记载的平王东迁,发生在770 BC年,这正是从3150 cal a BP开始的气候干燥期的极值点。
西汉建立与灭亡：春秋战国末年最为激烈的兼并战争发生在256-221 BC年间,随后,中国历史上第一个真正意义上的大一统王朝—秦朝就诞生了,而这正对应H6指示的一个干燥阶段的结束,下一个湿润期的开始（图4）。
西汉灭亡在公元九年（9 AD）,而在公元前后,气候开始趋干变冷[8],直到东汉与三国阶段,气候都没有明显的回返。也就是说,西汉的建立—发展—灭亡这一生灭过程与气候的干—湿—干演化阶段相吻合（图5）。
显示原图|下载原图ZIP|生成PPT图5西汉气候演化特点及流民情况
-->Fig. 5Comparison of climate change and refuge records over the Han Dynasty
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整个时段,以都城为标志的各王朝的重心,地理位置与现代降水呈现有规律的变化（图4）;这种规律恰好与上述指示风化强度与湖泊波动气候变化记录[30]具有反向关系,指示在气候湿润期,王朝的都城更趋于西北干旱区,气候干燥期则相反。这与周氏族在3550-2200 cal a BP期间由于气候变化而造成的迁移[45]是极其相似的,相信气候变化在其中起决定作用。
都城的选择,可能涉及方方面面的因素,自然环境的影响时时可起主导作用[46]。众多研究表明,在历史早期以农业为主且交通运输条件不发达的情况下,粮槽转运成本高,王朝的都城,如果不处在全国农业重心附近,社会维护成本就会增加,不利于保障统治集团的物资供应[47-48]。因此,都城往往与全国的农业重心有关,都城的变迁,标示了王朝的农业重心有所变化。而农业重心的变化,则与气候带的变迁有关联。对全新世季风变迁的研究表明,在东亚季风区,随着气候变化,夏季风的强弱也发生变化,气候带往往存在整体向西北扩展、向东南萎缩的特点[17, 49],但整体格局与现在相似。
综上所述,气候环境变化与早期中国历史社会演替之间存在密切关系：气候环境稳定,有助于社会的稳定与发展;气候环境的恶化,可引起社会动荡并进而造成王朝的更迭。3600-3050 cal a BP期间气候湿润,商王朝恰逢其时地稳定存在了500余年;3050-1800 cal a BP这个时段,气候逐渐变干,中国北方生存环境恶化,王朝的重心,渐趋南移。许多社会政治事件,往往与气候的变迁存在莫大关系。这些证据再次证实了中国社会历史演化与气候环境变化之间存在的耦合关系,“冷抑暖扬”的韵律[8]在中国早期历史也是存在的。
这种关系的内在机制如何?许多****从不同的角度有所阐述,但一直没有令人信服的解释。本文尝试从地理环境背景与王朝社会兴衰过程中经济状况两个因素做具体剖析,希望对这一问题的科学阐释,有所裨益。
4 中国北方地理环境特点及其对社会历史的影响
黄河流域所在的东部亚洲,处在青藏高原以东,亚洲内陆沙漠东南,东、东南靠太平洋,尽管地理空间较为广阔,但在交通工具相对原始的历史早期,山脉和海洋均是交通的屏障,造成这个区域相对比较独立与封闭,并具有典型的折扇形态。近东西偏南走向的昆仑山脉、秦岭、大别山脉与东北—西南走向的海岸带是扇形地带的两个边缘,扇面呈半圆弧形向东北、西北辐散开来。它是东亚冬季风的腹地、夏季风的边缘区域。夏季,季风来自西太平洋,是湿润气候的主导因素;冬季,季风来自于西北内陆和西伯利亚,与纬度地带性一起,是气温的主控因素。这种格局的气候,使区域气候环境与生态环境具有东南—西北的梯度变化特点：西北地区寒冷干燥,生物营养源相对匮乏,东南地区温暖湿润,生物营养源相对丰富。尤其值得注意的是,随着冬夏季风的强弱变化,气候带具有沿西北—东南方向整体推进的特征与趋势[17, 49];毋庸置疑,这也使得这种环境或生态梯度具有同步变化的特点。这种特有的气候环境特点与地理环境格局,使区域人类演化表现出如下几个方面的特点：
（1）气候暖湿期,夏季风强盛,气候带向西北内陆推进,为农业的发展拓展了新的空间,诱使人类向西北方向迁移。湿润的气候,造成生物营养源增加,激发出一个人口增加、经济繁荣的太平盛世。中全新世大暖期时的仰韶文化,便是这种气候期催生的一典型区域文化[50]。
（2）气候恶化期,夏季风减弱,气候带向东南方向萎缩。西北区气候干燥、生物营养源匮乏,便不能支撑如暖湿期那样多的人口规模,人类会向东南方向迁移。尤其是沿着西南、东南两个边缘的迁移,在新石器时代及早期文明阶段曾经多次出现[9, 39, 45, 51]。夏末,祖居太行山南麓的商人[43]与商末世居渭水流域的周人[45]就是在这种气候恶化期沿着这两个边缘向湿润区迁移的。从而造成相对狭小的东南地区区域人口密度增加,为争夺资源而引起的纷争产生并加剧,纷争的结果就是商代夏、周代商。
这种气候变化与区域人类演化的关系,具有Dorigo等[52]1983年所说的推拉效应特点,它能产生气候或生态移民,并且移民的方向是确定的,沿着扇形地貌的生态梯度最大的方向（西北—东南方向）开展,暖湿向西北,冷干向东南。这种人口迁移特征,在暖湿期可以缓解东南区的人口压力,从而舒缓了社会矛盾,有利于社会稳定;在冷干期则增加东南区域的人口压力,加剧了区域社会矛盾,引起社会的动荡与纷争。这也就使中原地区成为考古学上所说的民族大熔炉[53],融合各种区域文化而成就一统。
5 小农经济对气候变化的敏感性及其对社会的冲击：方式与机制
中国北方地理环境格局为气候变化如何影响中国社会、以何种方式影响中国社会的研究提供了契机,这是一种环境背景,同时也是一种影响,它使中国古代社会具有对环境变化的敏感响应。具体到对某个历史时期或某朝某代的影响,则是另外一个层次的影响。本文以西汉王朝为例,考察这种影响的方式及其特点。考察这个王朝的兴衰,本文从考察其生产关系的部分特点开始：① 西汉的食利集团与生产集团：前者包括皇族、贵族地主、官僚地主、工商地主和豪强地主、中小地主;后者包括自耕农、雇农、佃农、半佃农、奴婢等,自耕农是其主体。蒙文通[54]1957年认为,自耕农能够持续生存下去是西汉各种所有制共生共荣的基本经济条件。② 西汉的赋税：主要有算赋、口赋和田税。算赋的征收对象年龄在15~56岁,征收数量120钱/人（年）;口赋的征收对象年龄在7~14岁,数量23钱/人（年）。算赋、口赋以人头计算,无分贫富,达到纳税年龄,必须缴纳,上自王侯下至饥民与奴婢。田税为十五税一或三十税一;西汉初年为十五税一,到公元前155年（汉景帝前元二年）为三十税一,并成为西汉定制。土地所有者按照规定向政府如实申报其占有田亩,按亩数征收田租。田租的征收额根据每亩历年的平均产量来定数,即不论年岁的丰歉,也不计土地的肥瘩[55]。③ 西汉的徭役,包括卒更与正卒。服徭役的年龄,从23~56岁。每个成年男子每年服一个月徭役,称为卒更（不能亲自服役者,出钱二千由政府雇人代役）。此外,每年要戍边三天,不去者缴纳更赋三百钱。正卒（也就是兵役）,一生服两年;一岁为卫士,守卫都域或边疆,一岁为材官、骑士或楼船兵,驻守本郡。
上述兵役、徭役和赋税,表面上具有普遍性与无差别性,但实际上完全不是如此。例如兵役、徭役、宗室、诸侯、功臣的后代及两千石以上官员等,全家可以免役。地主、富人以钱财入于官府等方法,也可以博取免役特权。因此,徭役、兵役都要落在自耕农身上。《汉书·食货志》与《汉书·鲍宣传》记载,一个五至八口之家,往往是“其服役者不下二人”,以致“农桑失时”。而徭役、兵役就实际情况而言,执行也不严格,有时可以随意征发和任意延长;这对自耕农而言,又是一个沉重的负担。如果免除徭役,就要付代役金[54]。这对自耕农而言,无疑是雪上加霜。
一般而言,正常年份且没有意外情况发生（其实就是一个平均状态,也就是图6所示的温饱线）,一个五至八口之家的自耕农家庭,有田百亩,是能够维持劳动者及其家庭生活的;但情况往往是五六十亩,不足或严重不足。即便这样,他们也比雇农、佃农、半佃农情况要好得多[56-57]。
表1按照五口之家估算的西汉一般自耕农家庭的收支情况,有田60亩,男耕女织,总收入11400钱,总支出10340钱（这种收支平衡,对纺织一项收入估计或许过于乐观）。这约略指示,在无天灾或人祸的正常年份,总收入比总支出盈余10%左右,自耕农家庭处在温饱线上下,可勉强度日。
Tab. 1
表1
表1西汉自耕农家庭年收支情况
Tab. 1The economy budget of an owner-peasant family
| 家庭年收入 | 家庭年支出 | ||||||
|---|---|---|---|---|---|---|---|
| 粮 120石 | 园圃/家禽10石 | 纺织10匹 | 生存消费 | 简单再生产 | 租赋负担 | 其他 | |
| 7200 | 600 | 4000 | 口粮 80石,4800 食盐 1.8石,900 衣着 5匹,2000 | 留种 6石,360 饲料10石,600 农具 7石 420 | 赋敛 11石,660 田租 4石,240 | 祭祀/人际和医药 6石,360 | |
| 总计 11800 | 总计10340 | ||||||
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如气候暖湿,风调雨顺,收成则较好,盈余增多;如气候冷干,伤农误时,收成就差。这种生产与生活状态,使它们在自然灾害面前,表现的极其脆弱,稍有不慎,即有朝不保夕的担忧,更别说大旱大涝。也就是说,小农家庭对气候变化极其敏感。
自耕农家庭对气候的这种敏感性加上上述所及的西汉王朝不尽合理的社会制度,使自耕农很容易破产。《汉书·食货志》记载,在生活窘迫的情况下,他们可能不得不借贷度日,从而会受到高利贷的盘剥,于是开始卖田宅、鬻子孙以偿债,而沦为雇农、佃农、半佃农或奴婢,依附于豪强地主或者变成游民、流民、盗匪等。
这种现象,史料述及很多,可以说是一种普遍的情况。晁错在他的《论贵粟疏》中就写道：勤苦如此,尚复被水旱之灾,急政暴赋,赋敛不时,朝令而暮当具。有者半贾而卖,亡者取倍称之息（指百分之百的高利贷）。每遇这种情况,借贷、卖田宅、鬻子孙,就是一种必然选择。也就是说,在西汉,自耕农破产并向流民的演化在某种程度上是社会的必然,具体通过以下几个途径：① 气候变化、旱涝不调,② 兵役、徭役,③ 高利贷,④ 豪强兼并等,⑤ 特权阶层往往又通过免兵役、免徭役、免赋税等增加了自耕农的负担。这5个因素,气候变化是自然因素,其余为社会因素,它们往往联系在一起,共同促进自耕农的流失,甚或蜕变成流民（图6）。
图5为黄旗海H6剖面记录的西汉时期气候的干湿变化与流民关系,西汉流民存在两个特点：① 流民是西汉社会普遍的社会现象,在西汉王朝210年的社会历史中,史料记载210年里产生了较大规模的32次流民（15次/百年）;② 流民多与气候干旱或气候由湿润转入干旱的气候阶段有联系（西汉初期除外）。第一个集中暴发阶段是125-100 BC年,一个气候相对干燥期,这个气候期在史料记载中也多有述及[8];第二个集中爆发期在西汉的后期当气候再次趋于干旱化时。这种对比关系表明,流民在西汉的社会体制下,具有对气候变化的敏感响应,而流民主要来自于破产的小农家庭;因此,这种敏感响应,在西汉,其实是自耕农对气候变化的敏感响应的一种具体体现。
同时,这种不尽合理的社会体制,往往造成小农家庭人口增长不及特权阶层,使特权阶层增长过快,越来越庞大,而小农家庭则相对萎缩;这其实是人类社会历史发展过程中的一个普遍特点[10]。对西汉而言,社会群体不能共同承担包括气候所造成的灾难,这副担子就主要交给自耕农来承担;同时,国家每有祸事,首先波及的也是这个群体。因此,自耕农家庭在西汉社会环境下,具有不稳定和脆弱性的特点。而自耕农家庭阶层,作为一个生产阶层,又是西汉社会得以维持发展的焦点,这个阶层稳定,社会发展就进入一个良性循环,社会则稳定繁荣;这个阶层萎缩,社会发展就进入一个恶性循环,经济凋敝,社会衰退。
图6表示随着气候变化,西汉的生产集团与食利集团相对变化趋势：气候适宜期,风调雨顺,自耕农安居乐业,社会稳定;这种情况往往产生于一个王朝的初期或中期,相对清明的社会制度,会对食利集团有所限制,包括自耕农在内的劳动者集团相对庞大而稳定。气候干燥期,部分自耕农不能满足自给自足的生产活动时,只能靠借债和靠出卖田地维持暂时的生计,自耕农就进入上述西汉社会特有的恶性循环中之后,接下来他们的命运就是必然的：沦为流民[58-59]。这种情况往往产生于一个王朝的中晚期,这时,随着王朝早期相对清明的社会体制的消失,自耕农面临着诸多不公平的社会现象也日益突显,这时自耕农集团的减小和食利集团的膨胀之间,形成了一个正反馈作用：自耕农越来越萎缩,势力集团越来越膨胀,直至王朝的经济和社会秩序的崩溃。
显示原图|下载原图ZIP|生成PPT图6西汉自然—经济—人文系统相互作用示意图
-->Fig. 6Diagram of interaction between government, powerful groups and disadvantaged groups
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因此,公元前后,当一个百年尺度的湿润期结束时,随着早期积极安定生产的国家政策消失和赋税劳役等日益严重,统治集团内部“多畜奴婢,田宅无限”,土地兼并严重,灾民与流民的数量恶性膨胀,并最终导致了绿林、赤眉农民—流民大起义。王莽曾积极应对西汉末年的国家现实进行改制,这不失为一种明智的适应,但措施不利,加之王莽不合时宜地篡位,建立新朝,从而进一步激化了方方面面的社会矛盾,加速了西汉的灭亡。
这第二重影响,表面而言是因为自耕农对于气候变化具有敏感的响应,但其实质来自于社会体制内部,是社会不公平的反应。在汉朝以前的中国社会历史的各个发展阶段,理论上都会有所体现,但具体过程与特点,尚需具体分析。另外,不同属性的社会（例如,商代为奴隶制社会）,气候变化对社会发展的这种影响是如何表现的,也需结合具体史料详细考察,不能一概而论。
6 结论
（1）中国北方早期历史,气候环境大致经历了3580-3050 cal a BP、3050-1800 cal a BP两个阶段;前者为稳定的湿润气候期,后者为逐渐趋于干燥的气候期;与这两个阶段相对应,中国早期历史呈现出两种截然相反的政治生态。年代对比发现,商代夏、周代商、平王东迁、西汉甚至东汉灭亡等改朝换代的社会政治事件,都与沉积记录所指示的气候环境的显著变化（恶化）相对应。（2）气候变化影响中国社会历史发展,具有二重性：① 中国北方地理环境空间是扇状的,且自然环境具有梯度变化的特征,这种地理环境格局叠加在气候变化之上,具有特殊的加剧与舒缓区域社会矛盾的作用;② 小农经济具有对气候变化的特殊敏感性。不尽合理的社会体制往往通过一系列反馈作用将这种敏感性在气候恶化阶段“放大”,随之形成一系列连锁反应,由此造成的经济危机成为王朝崩溃重要因素。
The authors have declared that no competing interests exist.
参考文献 原文顺序
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被引期刊影响因子
| [1] | . The article studied the relation between the Climatic change and history in China in different historical periods , by comparing the climatic change and its influence on East Asian, Europe and North America . It pointed out , China ,especial in North China ,based on agriculture, was particularly vulnerable to climatic change .Climatic change could greatly affect all sectors of society . From Neolithic Age to Qing dynasty, the process of climatic change periodically between warm periods and cold periods was the one that nomadic and sedentary peoples conflicted and united. During warm periods, China was flourished ,united ,and prosperous. During cold periods ,climatic change led to the economic deterioration, nomadic inversion, peasant rebellion and even led to the economic and central shift from north to south .At last ,the author pointed out climate might be one of the factors which determined the political fate of North China ,and emphasized the importance of taking climate into account in studying historical events . |
| [2] | |
| [3] | . 本文讨论了历史时期气候变化对中国人口分布、社会经济、政治疆界的关系，试图说明全球气候变化对中国可能产生的人文影响。最后讨论了人地关系。 . 本文讨论了历史时期气候变化对中国人口分布、社会经济、政治疆界的关系，试图说明全球气候变化对中国可能产生的人文影响。最后讨论了人地关系。 |
| [4] | . . |
| [5] | . Abstract The Asian-Australian monsoon is an important component of the Earth's climate system that influences the societal and economic activity of roughly half the world's population. The past strength of the rain-bearing East Asian summer monsoon can be reconstructed with archives such as cave deposits, but the winter monsoon has no such signature in the hydrological cycle and has thus proved difficult to reconstruct. Here we present high-resolution records of the magnetic properties and the titanium content of the sediments of Lake Huguang Maar in coastal southeast China over the past 16,000 years, which we use as proxies for the strength of the winter monsoon winds. We find evidence for stronger winter monsoon winds before the B lling-Aller d warming, during the Younger Dryas episode and during the middle and late Holocene, when cave stalagmites suggest weaker summer monsoons. We conclude that this anticorrelation is best explained by migrations in the intertropical convergence zone. Similar migrations of the intertropical convergence zone have been observed in Central America for the period ad 700 to 900 (refs 4-6), suggesting global climatic changes at that time. From the coincidence in timing, we suggest that these migrations in the tropical rain belt could have contributed to the declines of both the Tang dynasty in China and the Classic Maya in Central America. |
| [6] | . We explore the association between climate change and warfare in eastern China over the past millennium from a macro-historic perspective. High-resolution palaeo-temperature reconstructions and the complete record of warfare incidence in eastern China were compared. Results show that warfare frequency in eastern China (its southern portion in particular) significantly correlated with the Northern Hemisphere temperature oscillations. Almost all peaks of warfare frequency and dynastic changes occurred in cooling phases. We suggest that in historic China, the reduction of thermal energy during cooling phases significantly shrank agricultural production. Such ecological stress interacted with population pressure and China unique historic and geographic setting to bring about the high frequencies of warfare over the last millennium. We recommend scholars take climate change into account as they consider the anthropology of warfare in the historic past. |
| [7] | . Abstract A record from Wanxiang Cave, China, characterizes Asian Monsoon (AM) history over the past 1810 years. The summer monsoon correlates with solar variability, Northern Hemisphere and Chinese temperature, Alpine glacial retreat, and Chinese cultural changes. It was generally strong during Europe's Medieval Warm Period and weak during Europe's Little Ice Age, as well as during the final decades of the Tang, Yuan, and Ming Dynasties, all times that were characterized by popular unrest. It was strong during the first several decades of the Northern Song Dynasty, a period of increased rice cultivation and dramatic population increase. The sign of the correlation between the AM and temperature switches around 1960, suggesting that anthropogenic forcing superseded natural forcing as the major driver of AM changes in the late 20th century. |
| [8] | |
| [9] | . <p> 在前人研究的基础上，系统梳理了中国过去2000年气候变化与社会的自然、经济、人文三大亚系统发展状况间的对应关系，从数百年至数十年的时间尺度上揭示了气候变化的过程在实质上也是社会结构重新构建的过程。具体有以下结论：①尽管并非所有的暖期社会都是繁荣昌盛的，但总体上说来，“冷抑暖扬”的文明韵律十分清晰；②气候变化对社会发展的影响，通过自然—经济—人文亚系统的各个环节而逐级传导，进而产生了五个层次的气候冲击与适应；③在过去2000年气候恶化阶段，与生态环境脆弱性密切相关的贫困人群生存问题是诱发社会动乱的重要原因；④气候只是社会发展的外部条件，人对生产关系的变革才是推动古代社会发展进程的根本动力；⑤随着科学技术的不断发展, 气候变化对古代社会发展的不利影响在总体上渐趋减轻。</p> . <p> 在前人研究的基础上，系统梳理了中国过去2000年气候变化与社会的自然、经济、人文三大亚系统发展状况间的对应关系，从数百年至数十年的时间尺度上揭示了气候变化的过程在实质上也是社会结构重新构建的过程。具体有以下结论：①尽管并非所有的暖期社会都是繁荣昌盛的，但总体上说来，“冷抑暖扬”的文明韵律十分清晰；②气候变化对社会发展的影响，通过自然—经济—人文亚系统的各个环节而逐级传导，进而产生了五个层次的气候冲击与适应；③在过去2000年气候恶化阶段，与生态环境脆弱性密切相关的贫困人群生存问题是诱发社会动乱的重要原因；④气候只是社会发展的外部条件，人对生产关系的变革才是推动古代社会发展进程的根本动力；⑤随着科学技术的不断发展, 气候变化对古代社会发展的不利影响在总体上渐趋减轻。</p> |
| [10] | |
| [11] | |
| [12] | |
| [13] | |
| [14] | |
| [15] | |
| [16] | |
| [17] | |
| [18] | . . |
| [19] | |
| [20] | . This paper presents a Levantine model for the origins of cultivation of various wild plants as motivated by the vagaries of the climatic fluctuation of the Younger Dryas within the context of the mosaic ecology of the region that affected communities that were already sedentary or semisedentary. In addition to holding to their territories, these communities found ways to intensify their food procurement strategy by adopting intentional growth of previously known annuals, such as a variety of cereals. The Levantine sequence, where Terminal Pleistocene and Early Holocene Neolithic archaeology is well known, is employed as a model for speculating on the origins of millet cultivation in northern China, where both the archaeological data and the dates are yet insufficient to document the evolution of socioeconomic changes that resulted in the establishment of an agricultural system. |
| [21] | . In the anoxic Cariaco Basin of the southern Caribbean, the bulk titanium content of undisturbed sediment reflects variations in riverine input and the hydrological cycle over northern tropical South America. A seasonally resolved record of titanium shows that the collapse of Maya civilization in the Terminal Classic Period occurred during an extended regional dry period, punctuated by more intense multiyear droughts centered at approximately 810, 860, and 910 A.D. These new data suggest that a century-scale decline in rainfall put a general strain on resources in the region, which was then exacerbated by abrupt drought events, contributing to the social stresses that led to the Maya demise. |
| [22] | . Several independent trajectories of subsistence intensification, often leading to agriculture, began during the Holocene. No plant-rich intensifications are known from the Pleistocene, even from the late Pleistocene when human populations were otherwise quite sophisticated. Recent data from ice and ocean-core climate proxies show that last glacial climates were extremely hostile to agriculture dry, low in atmospheric CO2, and extremely variable on quite short time scales. We hypothesize that agriculture was impossible under last-glacial conditions. The quite abrupt final amelioration of the climate was followed immediately by the beginnings of plant-intensive resource-use strategies in some areas, although the turn to plants was much later elsewhere. Almost all trajectories of subsistence intensification in the Holocene are progressive, and eventually agriculture became the dominant strategy in all but marginal environments. We hypothesize that, in the Holocene, agriculture was, in the long run, compulsory. We use a mathematical analysis to argue that the rate-limiting process for intensification trajectories must generally be the rate of innovation of subsistence technology or subsistence-related social organization. At the observed rates of innovation, population growth will always be rapid enough to sustain a high level of population pressure. Several processes appear to retard rates of cultural evolution below the maxima we observe in the most favorable cases. |
| [23] | . Climate change is increasingly been called a ‘security’ problem, and there has been speculation that climate change may increase the risk of violent conflict. This paper integrates three disparate but well-founded bodies of research – on the vulnerability of local places and social groups to climate change, on livelihoods and violent conflict, and the role of the state in development and peacemaking, to offer new insights into the relationships between climate change, human security, and violent conflict. It explains that climate change increasingly undermines human security in the present day, and will increasingly do so in the future, by reducing access to, and the quality of, natural resources that are important to sustain livelihoods. Climate change is also likely to undermine the capacity of states to provide the opportunities and services that help people to sustain their livelihoods. We argue that in certain circumstances these direct and indirect impacts of climate change on human security may in turn increase the risk of violent conflict. The paper then outlines the broad contours of a research programme to guide empirical investigations into the risks climate change poses to human security and peace. |
| [24] | . Warfare is seen as an adaptive ecological choice under conditions of population growth and resource limitation. Its major significance in the formation of the state lay in its ability to negate evolutionary constraints inherent in ranked societies. The evolutionary significance of warfare is discussed in terms of processes of cultural change which are largely internal. |
| [25] | . Emerging insights from adaptive and community-based resource management suggest that building resilience into both human and ecological systems is an effective way to cope with environmental change characterized by future surprises or unknowable risks. We argue that these emerging insights have implications for policies and strategies for responding to climate change. We review perspectives on collective action for natural resource management to inform understanding of climate response capacity. We demonstrate the importance of social learning, specifically in relation to the acceptance of strategies that build social and ecological resilience. Societies and communities dependent on natural resources need to enhance their capacity to adapt to the impacts of future climate change, particularly when such impacts could lie outside their experienced coping range. This argument is illustrated by an example of present-day collective action for community-based coastal management in Trinidad and Tobago. The case demonstrates that community-based management enhances adaptive capacity in two ways: by building networks that are important for coping with extreme events and by retaining the resilience of the underpinning resources and ecological systems. |
| [26] | |
| [27] | . The relationship between climate change and the macroeconomy in pre-industrial Europe has attracted considerable attention in recent years. This study follows the combined paradigms of evolutionary economics and ecological economics, in which wavelet analysis (spectrum analysis and coherence analysis) is applied as the first attempt to examine the relationship between climate change and the macroeconomic structure in pre-industrial Europe in the frequency domain. Aside from confirming previous results, this study aims to further substantiate the association between climate change and macroeconomy by presenting new evidence obtained from the wavelet analysis. Our spectrum analysis shows a consistent and continuous frequency band of 60-80 years in the temperature, grain yield ratio, grain price, consumer price index, and real wage throughout the study period. Besides, coherence analysis shows that the macroeconomic structure is shaped more by climate change than population change. In addition, temperature is proven as a key climatic factor that influences the macroeconomic structure. The analysis reveals a unique frequency band of about 20 years (15-35 years) in the temperature in AD1600-1700, which could have contributed to the widespread economic crisis in pre-industrial Europe. Our findings may have indications in re-examining the Malthusian theory. |
| [28] | . The climate–population relationship has long been conceived. Although the topic has been repeatedly investigated, most of the related works are Eurocentric or qualitative. Consequently, the relationship between climate and population remains ambiguous. In this study, fine-grained temperature reconstructions and historical population data sets have been employed to statistically test a hypothesized relationship between temperature change and population growth (i.e., cooling associated with below average population growth) in China over the past millennium. The important results were: (1) Long-term temperature change significantly determined the population growth dynamics of China. However, spatial variation existed, whilst population growth in Central China was shown to be responsive to both long- and short-term temperature changes; in marginal areas, population growth was only sensitive to short-term temperature fluctuations. (2) Temporally, the temperature–population relationship was obscured in some periods, which was attributable to the factors of drought and social buffers. In summary, a temperature–population relationship was mediated by geographic factors, the aridity threshold, and social factors. Given the upcoming threat posed by climate change to human societies, this study seeks to improve our knowledge and understanding of the climate–society relationship. |
| [29] | . Recent studies have shown strong temporal correlations between past climate changes and societal crises. However, the specific causal mechanisms underlying this relation have not been addressed. We explored quantitative responses of 14 fine-grained agro-ecological, socioeconomic, and demographic variables to climate fluctuations from A.D. 1500-1800 in Europe. Results show that cooling from A.D. 1560-1660 caused successive agro-ecological, socioeconomic, and demographic catastrophes, leading to the General Crisis of the Seventeenth Century. We identified a set of causal linkages between climate change and human crisis. Using temperature data and climate-driven economic variables, we simulated the alternation of defined "golden" and "dark" ages in Europe and the Northern Hemisphere during the past millennium. Our findings indicate that climate change was the ultimate cause, and climate-driven economic downturn was the direct cause, of large-scale human crises in preindustrial Europe and the Northern Hemisphere. |
| [30] | . <p>基于内蒙古东南缘黄旗海八台沟(40°50'2"N,113°22'44"E;1280m a.s.l.)剖面135cm厚的湖相地层5个AMS <sup>14</sup>C年龄的测定以及90块样品的孢粉、直径>50μm炭屑浓度、元素和粒度等高分辨率指标分析,重建黄旗海中晚全新世(3580~1630cal.a B.P.)的植被和气候环境演化过程。内蒙古黄旗海高分辨率指标记录揭示:3580~1630cal.a B.P.期间的黄旗海流域气候环境具有持续变干的特征,具体表现为:1)3580~3000cal.a B.P.间,黄旗海湖面较高,湖泊水位在1291m以上,高于现今湖面23m以上,且最高湖面出现在3380cal.a B.P.之前,之后湖泊水位有所下降;3380cal.a B.P.之前植被类型为针-阔混交林,之后转变为以松属为主的针叶林,气候凉湿。2)3000cal.a B.P.前后的约100年间,黄旗海快速变冷变干,湖泊迅速萎缩,植被转变为草甸草原;之后约1400年内,气候逐渐变干,温度有所上升,气候环境以暖干为特征;1630cal.a B.P.前后黄旗海湖面降到高出现在湖面不足9m的高度以下,之后再未出现超过此高度的湖侵。</p> . <p>基于内蒙古东南缘黄旗海八台沟(40°50'2"N,113°22'44"E;1280m a.s.l.)剖面135cm厚的湖相地层5个AMS <sup>14</sup>C年龄的测定以及90块样品的孢粉、直径>50μm炭屑浓度、元素和粒度等高分辨率指标分析,重建黄旗海中晚全新世(3580~1630cal.a B.P.)的植被和气候环境演化过程。内蒙古黄旗海高分辨率指标记录揭示:3580~1630cal.a B.P.期间的黄旗海流域气候环境具有持续变干的特征,具体表现为:1)3580~3000cal.a B.P.间,黄旗海湖面较高,湖泊水位在1291m以上,高于现今湖面23m以上,且最高湖面出现在3380cal.a B.P.之前,之后湖泊水位有所下降;3380cal.a B.P.之前植被类型为针-阔混交林,之后转变为以松属为主的针叶林,气候凉湿。2)3000cal.a B.P.前后的约100年间,黄旗海快速变冷变干,湖泊迅速萎缩,植被转变为草甸草原;之后约1400年内,气候逐渐变干,温度有所上升,气候环境以暖干为特征;1630cal.a B.P.前后黄旗海湖面降到高出现在湖面不足9m的高度以下,之后再未出现超过此高度的湖侵。</p> |
| [31] | . The pattern of Holocene palaeoclimatic change in arid-semiarid northern China is debated. The terminal Huangqihai Lake is located at the northern margin of the modern East Asian summer monsoon and sensitive to climate change. We present here a sedimentary section from Huangqihai lake basin which comprises lacustrine and fluvial deposits and is about 8-9 m above the present lake level. Quartz optically stimulated luminescence (OSL) dating was employed to construct the chronology of the section. Based on the OSL chronology and the sedimentological and granulometric analysis, we conclude that (1) the Huangqihai Lake experienced a humid climate during the early part of the Holocene (from c. 10.2 +/- 1.0 to 6.7 +/- 0.7 ka) with a persistent and stable high lake level; (2) the lake level began to decline indicating aridification between 8.7 +/- 0.8 ka and 6.7 +/- 0.7 ka, and the climate was drier and deteriorating, and the lake was turned into a playa for most of the time. In summary, the climate showed a general drying trend from the early Holocene to the late Holocene. |
| [32] | . Vegetation around the Daihai Lake, northern China, is very sensitive to climate changes. In this paper, pollen-based quantitative climate reconstructions using three methods [weighted averaging partial least squares method (WAPLS), modern analog technique (MAT), and pollen response surface method (PRS)] were conducted to obtain robust reconstructions of Holocene climate changes in the Daihai Lake area. The result obtained by the three methods all consistently show the annual precipitation to have been 5009“100 mm lower in the early Holocene, 10009“200 mm higher in the Mid-Holocene, and 5009“100 mm lower again in the late Holocene than at present. The WAPLS and the MAT methods also show quasi-synchronous oscillations of the mean annual temperature (Ta); 100°09“200°C lower in the Early Holocene and 100°09“300°C higher in the Mid-Holocene than today. The time period from 6200 to 5100 cal yr BP was the wettest and the warmest interval, with an annual precipitation (Pa) greater than 550 mm and mean annual temperature Ta higher than 6.500°C. Several cold and dry events can be identified to occur about 8200, 6000, and 4400 cal yr BP, with an annual precipitation less than 400 mm and a mean annual temperature colder than 4.500°C, respectively. The mean temperature of the warmest month (Tw) as reconstructed using both WAPLS and MAT methods was relatively stable during the Holocene, fluctuating about 00±200°C relative to the present level, but the PRS method suggests more varied Tw values in both amplitude and frequency. After 1500 cal yr BP, no consistent pattern can be observed from these three different analyses, probably because of the impact of intensified human disturbances on the natural vegetation. The fluctuations of annual precipitation (Pa) correspond to that observed in Dongge Cave in southern China. The differences might be linked to Indian monsoon and East Asia monsoon climates or caused by the different degree of dating precision, different temporal resolution, and different sensitive response of climate proxies to the climate variations. |
| [33] | . H99a sediment core recovered at the center of Daihai Lake in north-central China was analyzed at 4-cm intervals for pollen assemblage and concentration.The pollen record spanning the last ca 10,000 yr revealed a detailed history of vegetation and climate changes over the Daihai Lake region during the Holocene.From ca 10,250 to 7900 cal yr BP,arid herbs and shrubs dominated the lake basin in company with patches of mixed pine and broadleaved forests,indicating a mild and dry climatic condition.Over this period,the woody plants displayed an increasing trend,which may suggest a gradual increase in warmth and humidity.The period between ca 7900 and 4450 cal yr BP exhibits large-scale covers of mixed coniferous and broadleaved forests,marking a warm and humid climate.Changes in the composition of the forests indicate that both temperature and precipitation displayed obvious fluctuations during this period,i.e.,cool and humid ca 7900-7250 cal yr BP,warm and slightly humid ca 7250-6050 cal yr BP,warm and humid between ca 6050 and 5100 cal yr BP,mild and slightly humid ca 5100-4800 cal yr BP,and mild and humid ca 4800- 4450 cal yr BP.The period can be viewed as the Holocene optimum(characterized by a warm and moist climate) of north-central China,with the maximum(dominated both by warmesttemperatures and by richest precipitations) occurring from ca 6050 to 5100 cal yr BP.During the period of ca 4450-2900 cal yr BP,the woody plants declined,and the climate generally became cooler and drier than the preceding period.This period is characterized by a cold,dry episode from ca 4450 to 3950 cal yr BP,a warm, slightly humid interval between ca 3950 and 3500 cal yr BP and a mild,slightly dry episode from ca 3500 to 2900 cal yr BP,and appears to be a transition from warm and humid to cold and dry climatic conditions.Since ca 2900 cal yr ago,the forests disappeared and the vegetation density decreased,reflecting a cool and dry climate.However,a relative recovery of the woody plants occurring between ca 1700 and 1350 cal yr BP may denote an increase both in temperature and in precipitation.Fluctuations in the climatic condition of the Daihai Lake region were not only related to changes in the seasonal distribution of solar insolation and in the axis and intensity of the ocean currcnt in the western North Pacific but were also closely linked to variations in the position and strength of polar high-pressure systems and in the pattern and intensity of the Westerly winds. |
| [34] | . . |
| [35] | . |
| [36] | , Yancheva, Gergana; Nowaczyk, Norbert R; Mingram, Jens; Dulski, Peter; Schettler, Georg; Negendank, J rg F W; Liu, Jiaqi; Sigman, Daniel M; Peterson, Larry S; Haug, Gerald H (2007): Rock magnetism and X-ray flourescence spectrometry analyses on sediment cores of the Lake Huguang Maar, Southeast China. doi:10.1594/PANGAEA.587840, Supplement to: Yancheva, G et al. (2007): Influence of the intertropical convergence zone on the East Asian monsoon. Nature, 445, 74-77, doi:10.1038/nature05431 |
| [37] | |
| [38] | |
| [39] | |
| [40] | . 历史学研究表明,古代文献如记载的五帝:黄帝、颛顼、帝喾、唐尧、虞舜,可能应该视为一个时代,而不局限于五个人.获得较多支持的观点是:这个时代约在6-4kaBP,而且也不限于华夏集团,至少还包括东夷集团、苗蛮集团等.因此,从地望上讲,也不限于中原地区,还包括东部沿海及长江中游.考古学研究表明,6-4kaBP正是新石器时代晚期,后期可称为铜石并用时代.从考古文化来看,中原地区为仰韶文化中、晚期到龙山文化.东部地区为大汶口文化及(山东)龙山文化.其中在3500BC是仰韶文化中、晚期的交界,以及大汶口文化早、中期的交界.环境考古研究表明,6-4kaBP是一个由湿润气候向干旱气候转变的过渡时期.特别6.0-5.6kaBP有湿润气候的证据.4kaBP前后则明显进入晚全新世的干旱期,在此期间还包括5.5kaBP和4.2-4.0kaBP两次气候突变.现代气候资料及模拟研究表明,由早、中全新世的湿润气候向晚全新世的干旱气候转变的主要原因为岁差变化.但是,5.5kaBP及4.2-4.0kaBP的两次冷干气候突变,则可能与热盐环流的突然减弱有关,而热盐环流减弱可能是太阳活动减弱的结果. . 历史学研究表明,古代文献如记载的五帝:黄帝、颛顼、帝喾、唐尧、虞舜,可能应该视为一个时代,而不局限于五个人.获得较多支持的观点是:这个时代约在6-4kaBP,而且也不限于华夏集团,至少还包括东夷集团、苗蛮集团等.因此,从地望上讲,也不限于中原地区,还包括东部沿海及长江中游.考古学研究表明,6-4kaBP正是新石器时代晚期,后期可称为铜石并用时代.从考古文化来看,中原地区为仰韶文化中、晚期到龙山文化.东部地区为大汶口文化及(山东)龙山文化.其中在3500BC是仰韶文化中、晚期的交界,以及大汶口文化早、中期的交界.环境考古研究表明,6-4kaBP是一个由湿润气候向干旱气候转变的过渡时期.特别6.0-5.6kaBP有湿润气候的证据.4kaBP前后则明显进入晚全新世的干旱期,在此期间还包括5.5kaBP和4.2-4.0kaBP两次气候突变.现代气候资料及模拟研究表明,由早、中全新世的湿润气候向晚全新世的干旱气候转变的主要原因为岁差变化.但是,5.5kaBP及4.2-4.0kaBP的两次冷干气候突变,则可能与热盐环流的突然减弱有关,而热盐环流减弱可能是太阳活动减弱的结果. |
| [41] | |
| [42] | |
| [43] | |
| [44] | |
| [45] | . In Chinese history, the development of the Zhou tribes and the dynasties that succeeded them between 3550 and 2200 BP in the middle reaches of the Yellow River is known as the period of ive Relocations . Most of these relocations appear to have been forced by the pressure of nomadic invasions and occupations from the northern steppe. Historians simply attributed these relocations to political and military causes. However, palaeoclimatic studies show that the Zhou tribes and their successor dynasties developed at the demise of the Holocene Climatic Optimum when regional climate became highly variable and unstable. An integrated analysis of environmental change over the Loess Plateau and the Mongolian steppe facilitates a credible understanding of the linkage between climatic events and these relocations. It indicates that the relocations caused an expansion or contraction of the settled regions over the drought-prone semi-arid lands. During climatic amelioration, dry farming societies pushed upward to the Loess Plateau where increased precipitation and soil moisture allowed cereals to be cultivated. When hit by droughts and the associated disasters, both the dry farming societies and the nomadic tribes had to move southward to find an environment suitable for their food production. Migration and relocation were, therefore, basic strategies to secure the resources necessary to sustain an agricultural economy. The settled frontier was pulled back as dry farming societies from the upland plateau retreated to the lowland riverbanks of the Guanzhong Basin. Even though there were political and military intentions, climatic events played an essential role in the relocations of the Zhou tribes and the successive dynasties. |
| [46] | |
| [47] | |
| [48] | . |
| [49] | |
| [50] | . Abstract The lack of a precisely-dated, unequivocal climate proxy from northern China, where precipitation variability is traditionally considered as an East Asian summer monsoon (EASM) indicator, impedes our understanding of the behaviour and dynamics of the EASM. Here we present a well-dated, pollen-based, ~20-yr-resolution quantitative precipitation reconstruction (derived using a transfer function) from an alpine lake in North China, which provides for the first time a direct record of EASM evolution since 14.7 ka (ka = thousands of years before present, where the "present" is defined as the year AD 1950). Our record reveals a gradually intensifying monsoon from 14.7-7.0 ka, a maximum monsoon (30% higher precipitation than present) from ~7.8-5.3 ka, and a rapid decline since ~3.3 ka. These insolation-driven EASM trends were punctuated by two millennial-scale weakening events which occurred synchronously to the cold Younger Dryas and at ~9.5-8.5 ka, and by two centennial-scale intervals of enhanced (weakened) monsoon during the Medieval Warm Period (Little Ice Age). Our precipitation reconstruction, consistent with temperature changes but quite different from the prevailing view of EASM evolution, points to strong internal feedback processes driving the EASM, and may aid our understanding of future monsoon behaviour under ongoing anthropogenic climate change. |
| [51] | |
| [52] | . |
| [53] | |
| [54] | |
| [55] | |
| [56] | |
| [57] | |
| [58] | |
| [59] |
