Advances in Meteorology
Volume 2016 (2016), Article ID 3217038, 12 pages
http://dx.doi.org/10.1155/2016/3217038

Review Article

1600 AD Huaynaputina Eruption (Peru), Abrupt Cooling, and Epidemics in China and Korea

Jie Fei,¹ David D. Zhang,² and Harry F. Lee²

¹Institute of Chinese Historical Geography, Fudan University, Shanghai 200433, China
²Department of Geography, The University of Hong Kong, Pokfulam, Hong Kong

Received 9 April 2015; Revised 9 July 2015; Accepted 19 August 2015

Academic Editor: Steffen Mischke

Copyright © 2016 Jie Fei et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract.

The 1600 AD Huaynaputina eruption in Peru was one of the largest volcanic eruptions in history over the past 2000 years. This study operated on the hypothesis that this event dramatically affected the weather and environment in China and the Korean Peninsula. Over the course of this research the Chinese and Korean historical literatures as well as dendrochronology records were examined. The historical evidence points to the conclusion that the eruption was followed by an abrupt cooling period and epidemic outbreaks in 1601 AD within both China and the Korean Peninsula. These records manifested themselves in unseasonably cold weather resulting in severe killing frosts in northern China in the summer and autumn of 1601 AD. In southern China (Zhejiang and Anhui Provinces and Shanghai Municipality), July was abnormally cold with snow, with an autumn that saw anomalously hot weather. In addition, there was unseasonable snowfall that autumn within Yunnan Province. Widespread disease outbreaks occurred in August, September, and October in northern and southern China. In Korea, the spring and early summer of 1601 AD were unusually cold, and conditions led to further widespread epidemics occurring in August.

1. Introduction

Volcanic eruptions eject massive amounts of gas and ash into the stratosphere and troposphere, reducing solar insolation and resulting in climatic and environmental effects [1–8]. Major volcanic eruptions are capable of affecting short-term climatic change on hemispheric and global scales.

For example, the 1991 AD Pinatubo eruption (Philippines) caused the largest perturbation of the 20th century to the particulate content of the stratosphere; and the radiative influence of the injected particles put an end to several years of globally warm surface temperatures [9, 10]. The 1883 AD Krakatoa eruption (Indonesia) caused dimmed suns and blood red skies in the Northern Hemisphere [11]. Similar disturbances have been reported after other major volcanic eruptions, for example, 1815 AD Tambora eruption and the unidentified eruptions in 1452 AD and circa 626 AD [12–17]. Even 2000 years ago, Plutarch and others surmised that the eruption of Mount Etna in 44 BC dimmed the sun and suggested that the resulting cooling caused crops to fail and even created famine within the Roman Empire and Egypt [6, 18]. Within China, there were dimmed suns, anomalously cold temperatures, crop failures, and famine the following year, in 43 BC, following the 44 BC Etna event [19].

Research on climatic effects using Chinese historical literature, written following major historical volcanic eruptions, has achieved encouraging progress during the past decades. Cao et al. (2012) identified evidence of climatic downturn in China following the 1815 AD Tambora eruption [20]. Fei and Zhou (2006) suggested that abrupt cooling occurred in 939–941 AD in China following the prolonged 934–939 AD Eldgjá eruption, Iceland [21].

The relationship between volcanic eruptions and abrupt cooling is therefore evident, and, recently, increasing attention has focused on the possible cause and effect relationship between volcanic eruptions and precipitation anomalies [22, 23]. It has been suggested that extreme droughts in China could be related to the volcanic eruptions during the past 500 years, because large volcanic eruptions possibly reduced the summer monsoon in East Asia [24, 25].

The epidemic effects of major volcanic eruptions have also long intrigued volcanologists [5, 26–28]. Stothers (1999) examined seven major volcanic eruptions during the past two millennia and found that most of them were followed by several years containing epidemics in Europe and the Middle East [4]. The 1783-1784 AD Laki (Lakigiga) eruption (Iceland) caused dense volcanic dry fog and a significant shift in regional climate systems that are potentially responsible for endemic diseases and high mortality rates seen in England and France during that time [29–31]. However, as a whole, the possible epidemic effects of volcanic eruptions during the past 2000 years have not been discussed in detail, and the mechanisms of contagion and spread of such epidemics have not yet been identified.

In addition, volcanic eruptions result in local disease outbreaks in the vicinity of volcanoes, due to poor hygiene and limited access to drinking water which has been contaminated with volcanic ash and debris. An example of this is following the 1815 AD Tambora volcanic eruption where populations suffering from violent diarrhea were prevalent in the vicinity of the volcano [16]. Another was a regional outbreak of measles that occurred after the eruptions of Mt. Pinatubo in 1991 AD [27].

2. The 1600 AD Huaynaputina Eruption, Peru

Huaynaputina Volcano (16.6°S, 70.9°W) is located in southern Peru, South America. The eruption in 1600 AD was the largest volcanic eruption in South America spanning the past 2000 years [32–36]. The eruption started on February 19, 1600 AD, and lasted until March [32–34, 37]. The economy of southern Peru was severely disrupted and did not recover during most of the 17th century [38, 39].

The sustained eruption column was estimated to be 27–35 km high during the Plinian phase on February 19-20, 1600 AD. The eruption reached a significantly higher altitude than the tropopause, thus making it capable of affecting the atmospheric environment on a global scale [34].

The eruption produced ~70 Mt. of global average stratospheric H₂SO₄ loading, which makes it one of the largest volcanic eruptions in world history over the past two millennia [32, 40]. For example, that of the 1815 Tambora eruption was estimated at 60 Mt. [13], 93–118 Mt. [41], and 108 Mt. [42]. However, stratospheric H₂SO₄ loading of the Huaynaputina eruption was much higher than those of the 1883 Krakatoa (22 Mt. [42]) and 1991 Pinatubo eruptions (30 Mt. [42]).

The volcanic ash from Huaynaputina formed a widespread lobe of ~95,000 km² within the 1-cm isopach [34]. Historical accounts indicate significant ash fall in Lima (~850 km north of the volcano) and on a ship 1,000 km off the Peruvian coast [32]. The fine ash and volcanic glass from the eruption were also identified in the South Pole ice core in Antarctica and possibly the GISP2 ice core in Greenland [32, 34, 43, 44].

Signals corresponding to the Huaynaputina eruption were identified in a large number of Antarctic and Greenland ice cores, thus indicating the potential global influence of the eruption. Volcanic acidity peaks corresponding to the Huaynaputina eruption were identified in the Greenland ice cores of Crete [45, 46], GRIP [47], and Summit [48]. Excess peaks corresponding to the Huaynaputina event were also identified in the Greenland ice cores of GISP2 [49], and Antarctic ice cores of Law Dome [50], Plateau Remote [51], SP2001 [52], PS1 (near the Amundsen-Scott Base) [43], Talos Dome (East Antarctica) [53], and Dome Fuji [54].

It is well known that the other three tropical eruptions produced abrupt global cooling [13, 16, 55]. Considering the magnitude of the Huaynaputina eruption, it should have been capable of producing significant global climatic effects. Previous research has revealed that the Huaynaputina eruption was followed by abrupt cooling in many regions in the world [32, 36].

A series of dendroclimatology studies have brought robust evidence to bear to support dramatic abrupt cooling in 1601 AD. Briffa et al. (1998) suggested that the summer of 1601 AD has the potential of being the coldest on record over the past 600 years according to a synthesis of dendrochronological data in northern Eurasia and North America [55]. Scuderi (1990) identified that 1601 AD was abnormally cold according to the temperature-sensitive tree-ring chronologies in the Sierra Nevada [56]. Jones et al. (1995) synthesized a temperature-sensitive network of tree-ring chronologies in North America and Western Europe and suggested that 1601 AD possessed the summer with the most dramatic shifts to unseasonably cold weather patterns [57].

Low temperature was shown around 1600 AD in a ring-width record derived from the June–August Alpine temperature proxy over 951–1527 AD in the Swiss and Austrian Alps [58]. 1601 AD was shown to be extremely cold in the maximum latewood density data from trees at thirteen temperature-sensitive sites along the northern tree line of North America [59]. In the centre of Spain, 1601 AD was the most unfavourable for tree growth, representing the minimum index in the regional chronology [60].

Evidences of dramatic cooling in 1601 AD also exist in the light ring and frost ring chronologies, which record abnormally low temperature in growing seasons. LaMarche Jr. and Hirschboeck (1984) identified a very significant frost ring in 1601 AD in western USA [61]. Filion et al. (1986) and Yamaguchi et al. (1993) identified a significant light ring event in 1601 AD near Bush Lake, Canada [62, 63]. Hantemirov et al. (2004) also identified significant frost and light rings in 1601 AD in the Polar Urals and Yamal Peninsula in northwestern Siberia [64].

The review of historical records corresponds to a dramatic global cooling event from the data collected above, and the historical sources indicate that the summer of 1601 was unusually cold in England and Italy [65]. The winter of 1601 was very severe in Russia, Latvia, and Estonia [36]. In Sweden, record amounts of snow in the winter of 1601 were followed by a rainy spring. The resulting harvest was insufficient to feed the population leading to hunger and disease [66]. Fei and Zhou (2009) investigated the possible climatic effects in northern China following the Huaynaputina eruption. It was discovered that killing frost occurred in 1601 AD and resulted in widespread crop failures throughout the region [67].

Here we investigate the possible climatic and epidemic effects in China and Korea following the 1600 AD Peruvian Huaynaputina eruption. After a careful literature survey, we found that significant abrupt cooling and epidemics occurred mainly in 1601 AD in China and Korea.

3. Materials and Methods

Our study of the possible climatic and epidemic effects of the Huaynaputina eruption in China and Korea is mainly based on the available historical literature. The Chinese and Korean historical texts were examined systematically. A few thousand literary sources were examined, though it turned out that only a small fraction of the historical record contains useful information.

Most of our records were discovered in the Chinese historical local gazetteers (Di fang zhi) (Tables 1, 2, and 3). This type of historical source material is unique and very substantial, especially for the history of the Ming (1368–1644 AD) and Qing (1644–1911 AD) dynasties. There are a few thousand extant historical local gazetteers in China [68]. The printed and/or electronic copies are available in the Libraries of Fudan University, the Libraries of the University of Science and Technology of China, and the Shanghai Library.

Table 1: Historical records of the abrupt cooling and epidemics in southern China in 1601 AD.

County, province
Description
Source

Wuzhen, Hangzhou, Huzhou, Tongxiang, and Nanxun, Zhejiang Province
Wanli Reign Period, 29th year (February 3, 1601 AD–January 22, 1602 AD): it was chilly in the 6th month (June 30–July 28, 1601 AD). People took on double layered and cotton clothes. It was said that there was a heavy snow in the mountains of the Fuyang County, and the county sheriff took a tank of snow and submitted it to the province governor. It was also said that there was significant snowfall in the mountains of Hangzhou Prefecture. It turned hot in the 7th month (July 29–August 27, 1601 AD) and was still hot in the 8-9th months (August 28–October 25, 1601 AD). People even soaked in water in order to keep cool. Most of the families were hit by epidemics.
Le Li, Notes on Experience (Jian wen za ji) (circa 1610).
Similar records are found in local gazetteers, including
① Yun Zheng et al., Gazetteer of the Hangzhou Prefecture (Hangzhou fu zhi) (1779), Vol. 56,
② Yuanhan Zong and Shichang Guo, Gazetteer of the Huzhou Prefecture (Huzhou fu zhi) (1874), Vol.44,
③ Chen Yan, Gazetteer of the Tongxiang County (Tongxiang xian zhi) (1887), Vol. 20.,
④ Rizhen Wang, Gazetteer of the Nanxun Town (Nanxun zhen zhi) (1859), Vol. 19.

Shidai County (modern Shitai County, Anhui Province)
29th year (of the Wanli Reign Period)…, in the 6th month of this summer (June 30–July 28, 1601 AD); it was very cold. All the people took on cotton coats. Snow fell and piled up in the remote mountains. It turned hot in the 7th month (July 29–August 27, 1601 AD) and was still hot in the 8th month (August 28–September 25, 1601 AD). Most of the people fell ill in the Wu and Yue areas (including Zhejiang Province, Shanghai Municipality, and southern Jiangsu Province) and the areas to the north and south of the Yangtze River.
Zizhuang Yao and Tiyuan Zhou, Gazetteer of the Shidai County (Shidai xian zhi) (1675), Vol. 2.

Songjiang county, Shanghai Municipality
Xinchou year (i.e., the 29th year of the Wanli Reign Period) 6th month, 17th day (July 16, 1601 AD): it poured all day and all night. A flood destroyed the crops in the northern area of the county. It suddenly turned freezing cold. It was said that there was more than one chi (1 chi ≈ 0.3 m) of snow in Fuyang County, Hangzhou Prefecture.
Yuegong Fang and Jiru Chen, Gazetteer of the Songjiang Prefecture (Songjiang fu zhi) (1630), Vol. 47.

Kunming, Yunnan
9th month (September 26–October 25, 1601 AD): there was a heavy snowfall.
Chengxun Fan and Jiwen Wang, General Gazetteer of Yunnan Province (Yunnan tong zhi) (1691), Vol. 28.

Ninggang, Jiangxi
A great epidemic. Nearly half of the people were killed.
Yuda Chen, Gazetteer of Yongning County (Yongning xian zhi) (1683), Vol. 1.

Xingguo, Jiangxi
A great drought and epidemic.
Shangyuan Zhang, Gazetteer of the Lianzhui County (Lianshui zhi lin) (1711), Vol. 15.

Shicheng, Jiangxi
A great epidemic.
Yaojing Guo, Gazetteer of Shicheng County (Shicheng xian zhi) (1660), Vol. 8.

Dayu, Jiangxi
There was a great epidemic in this year.
Yinchang Chen, Gazetteer of the Dayu County (Dayu xian zhi) (1874), Vol. 24.

Nankang, Jiangxi
4th month (May 2–May 31, 1601 AD): a great epidemic.
Ziyun Qiu, Gazetteer of the Nankang County (Nankang xian zhi) (1936), Vol. 10.

Liancheng, Fujian
A great epidemic.
Shijin Du, Gazetteer of the Liancheng County (Liancheng xian zhi) (1666), Vol. 1.

Xinhua, Hunan
When autumn came, there were drought and epidemic.
Xiaolong Yu and Wenzhu Yang, Gazetteer of the Xinhua County (Xinhua xian zhi) (1668), Vol. 11.

Guizhou Province
4th month (May 2–May 31, 1601 AD): no rain. 5th month (June 1–June 29th, 1601 AD): a great famine… 7th month (July 29th–August 27th, 1601 AD): a great epidemic.
Shenji Cao and Xun Pan, General Gazetteer of Guizhou Province (Guizhou tong zhi) (1673), Vol. 27.

Counties with abrupt cooling. Counties with epidemics.

Table 2: Historical records of the abrupt cooling and epidemics in northern China in 1601 AD.

County, province
Description¹
Source

Xincai, Henan
Since the 9th day of the 1st month (of the 29th year of the Wanli Reign Period, February 11, 1601 AD), it snowed heavily for 40 days, and the melted snow destroyed the wheat. The following epidemic killed innumerable people, and all the farmlands were deserted.
Hongxian Tan and Minfu Lü, Gazetteer of the Xincai County (Xincai xian zhi) (1691), Vol. 7.

Dingxiang, Shanxi
It did not rain in summer and autumn. There was an epidemic that killed numerous people. Even family members and relatives did not dare to have intimate physical contact with each other. There was a drought and a frost disaster that caused crop failure, and prices of crops rose to extraordinary levels.
Shijiong Wang and Hanyuan Niu, Gazetteer of the Dingxiang County (Dingxiang xian zhi) (1712), Vol. 7.

Lishi, Shanxi
A frost completely destroyed the crops (29th year of the Wanli Reign Period, 1601 AD). A great epidemic came in the spring of the 30th year of the Wanli Reign Period (1602 AD) and killed a great number of people.
Daoyi Wang, Gazetteer of the Fenzhou Prefecture (Fenzhou fu zhi) (1611), Vol. 16.

Huai’an, Hebei
There was a snow in the summer.
Dakun Yang and Jizeng Qian, A Gazetteer of the Huai’an County (Huai’an xian zhi) (1741), Vol. 22.

Xuanhua, Hebei
There was a frost in the summer.
Tan Chen, A Gazetteer of the Xuanhua County (Xuanhua xian zhi) (1711), Vol. 5.

Chicheng, Hebei
There was a frost in the summer.
Tun Zhang, A Gazetteer of the Longmen County (Longmen xian zhi) (1712), Vol. 2.

Yuxian, Hebei
There was a frost in the summer.
Ying Li, A Gazetteer of the Yu Prefecture (Yu zhou zhi) (1659), Vol. 1.

Yangyuan, Hebei
There was a frost in the summer.
Chongguo Zhang, A Gazetteer of the Xining County (Xining xian zhi) (1712), Vol. 1.

Laiyuan, Shanxi
A frost totally destroyed the crops.
Shizhi Liu and Wenyao Zhao, A Gazetteer of the Guangchang County (Guangchang xian zhi) (1630).

Guangling, Shanxi
There was a frost in the summer.
Huandou Li and Wuding Wang, A Gazetteer of the Guangling County (Guangling xian zhi) (1685), Vol. 1.

Xinzhou, Shanxi
A frost destroyed the crops in the 8th month (August 28–September 25th, 1601 AD).
Renlong Zhou and Gusui Dou, A Gazetteer of the Xin Prefecture (Xin zhou zhi) (1747), Vol. 4.

Jingle, Shanxi
A wind and frost destroyed the crop on the 25th day of the 7th month (August 22, 1601 AD). There was a great famine, and people even resorted to cannibalism.
Tuchang Huang, A Gazetteer of the Jingle County (Jingle xian zhi) (1695), Vol. 4.

Baode, Shanxi
A killing frost completely destroyed the crops on the 26th day of the 7th month (August 23, 1601 AD). The markets in the city were closed for nine days. People fled away and sold their children. There were victims of starvation everywhere. People were in such a weakened state they even did not care about the deaths of members of their own family.
Kechang Wang and Menggao Yin, A Gazetteer of the Baode Prefecture (Baode zhou zhi) (1710), Vol. 3.

Shenchi, Shanxi
A frost destroyed the crops in the 7th month (July 29–August 27th, 1601 AD). A great famine occurred in the Jingle and Shenchi counties.
Changqing Cui et al., A Gazetteer of the Shenchi County (Shenchi xian zhi) (1880), Vol. 9.

Zuoquan, Shanxi
A frost killed the crops in the 8th month (August 28–September 25, 1601 AD).
Tianxi Yang and Weitai Hou, A Gazetteer of the Liao Prefecture (Liao zhou zhi) (1673)., Vol. 7.

Linxian, Shanxi
There was a bitter early frost on the 9th day of the 8th month (September 5, 1601 AD). The crops were destroyed. There was a great famine. People ate tree barks and grass roots.
Daoyi Wang, et al., A Gazetteer of the Fenzhou Prefecture (Fenzhou fu zhi) (1611), Vol. 16.

Lishi, Shanxi
A frost destroyed crops in Yongning County. There was a great famine.
Daoyi Wang, et al., A Gazetteer of the Fenzhou Prefecture (Fenzhou fu zhi) (1611), Vol. 16.

Xixian, Shanxi
During the last ten days of the 10th month (November 15–November 24, 1601 AD), it snowed heavily. The snow was three chi deep. It was considered to be a propitious omen…. There was a frost in the 8th month (August 28–September 25th, 1601 AD) that reduced the harvest.
Yikai Qian, A Gazetteer of the Xi Prefecture (Xi zhou zhi) (1710), Vol. 24.

Yulin, Shaanxi
A frost destroyed the crops in autumn.
Jicong Tan, Gazetteer of the Yansui Fort (Yansui zhen zhi) (1673), Vol. 5.

Yulin, Shaanxi
There were successive snow and hail events in the 8th month (August 28–September 25, 1601 AD), and the crops were totally destroyed.
Tingyu Zhang and Zhaonan Qi, Continuation of Comprehensive Study of Documents (Xu wenxian tong kao) (1767), Vol. 223.

Mizhi, Shaanxi
A frost destroyed the crops in the 7th month (July 29–August 27, 1601 AD).
Yangqi Ning, Gazetteer of Mizhi County (Mizhi xian zhi) (1681), Vol. 1.

Yan’an, Shaanxi
A frost destroyed the crops in the autumn.
Hui Hong, Revised Gazetteer of Yan’an Prefecture (Chongxiu Yan’an fu zhi) (1802), Vol. 6.

Ningxian, Gansu
There was a frost in the 7th month (July 29–August 27, 1601 AD).
Benzhi Zhao, New Gazetteer of the Qingyang Prefecture (Xinxiu Qingyang fu zhi) (1761), Vol. 37.

Yangqu, Shanxi
There were epidemics and great famines in the 29th and 30th years of the Wanli Reign Period (i.e., 1601-1602 AD).
Mengxiong Dai, Fangtai Li and Fangfan Li, Gazetteer of the Yangqu County (Yangqu xian zhi) (1682), Vol. 1.

Qingxu, Shanxi
There were a great drought and resulting epidemic.
Xunxiang Wang and Xiaozun Wang, Gazetteer of the Qingyuan Town (Qingyuan xiang zhi) (1882), Vol. 16.

Linyou, Shaanxi
There were drought and epidemic outbreaks in 1601 AD in Linyou County.
Ruwei Wu and Yuantai Liu, Gazetteer of the Linyou County (Linyou xian zhi) (1657), Vol. 1.

Counties with abrupt cooling. Counties with epidemics.

If a weather event is recorded in two or more local gazetteers, the most original or the most detailed one is given.

Table 3: Historical records of the abrupt cooling and epidemics in Korea in 1601 AD.

Location
Description
Source

Kangwon Prefecture, Korea
The Magistrate of the Gangneung City (Gangneung Bu, a city of the Kangwon Prefecture, i.e., Kangwon Do), Si Sin, reported that chilly wind was always blowing, and the weather was always gloomy and hazy since the late spring. The seedlings rotted and faded away.
It rained and snowed on the 5th day of this month (May 6, 1601 AD). The mountains and plains were in white. This is really abnormal as it is summer now. (The date of this report was Jiawu day, 4th month, 34th year, Seonjo Reign Period, i.e., May 28, 1601 AD.)
Annals of King Seonjo, Vol. 136.

Hwanghae Prefecture, Korea
The Governor of the Hwanghae Prefecture (Hwanghae Do), I-Mun Seong, reported that there were severe droughts in all of the counties from the spring to summer. It shined one moment and rained the next, and the chilly wind always blew. The wheat failed to flower, and the rice failed to grow. The paddy fields were very dry and could not be ploughed. In the seeded fields, the seeds did not sprout. We really worried about the farm work. (The date of this report was Bingshen day, 4th month, 34th year, Seonjo Reign Period, i.e., May 30, 1601 AD.)
Annals of King Seonjo, Vol. 136.

Near Seoul, Korea
King Seonjo said that it was very hot and wet these days, and numerous people fell ill. We should take good care of ourselves, so that the patients would recover and no longer feel miserable. (The record does not mention the location. It should refer to the entire Korean Peninsula or at least the vicinity of the capital, Seoul, because this record is an order of the king.) (The date of this report was Renyin day, 7th month, 34th year, Seonjo Reign Period, i.e., August 4, 1601 AD)
Annals of King Seonjo, Vol. 139.

Counties with abrupt cooling. Counties with epidemics.

Some of the records were found in the historical diaries (Table 1). This type of source is particularly valuable as it contains first-hand accounts of climatic and epidemic events.

The climatological and epidemiological records in Korea were discovered in the Annals of the Choson Dynasty (also known as Choson Wangjo Sillok) (Table 3), which comprises 25 parts and 1,893 volumes and covers 472 years (1392–1863 AD) of the history of the Choson Dynasty (1392–1910 AD). The annals are in classical Chinese and adopt the Chinese lunar calendar. The compilations were commenced at a specific time following shortly after a king’s death by the Office for Annals Compilation of Korea. Therefore the Annals of the Choson Dynasty are highly reliable. The Annals of the King Seonjo (Seonjo Sillok) are a part of this record. It comprises 263 volumes and covers the reign of King Seonjo (r. 1567–1608 AD).

In addition, European and American historical records of climatic and epidemic events were also examined; most of these were carried over from relevant previous studies.

Dendrochronology records were examined extensively, in order to give a general scenario of the climatic effects around the world.

Volcanic related signals in ice cores in Greenland and Antarctica were examined carefully in order to verify the potential global influence of the eruption.

4. Abrupt Cooling and Epidemics in 1601 AD in Southern China

The year of 1601 AD witnessed anomalous summer and autumn seasons in southern China. It was cold in the summer and abnormally hot in the autumn. Following the cold summer and hot autumn, widespread disease broke out (Figures 1, 2, and 3; Tables 1, 2, 3, and 4).

Table 4: Temporal distribution and weather background of the epidemics in China and Korea in 1601 AD.

County, province
Weather background
Time

Xincai, Henan
Cold
Spring (February 3–May 1, 1601 AD)

Nankang, Jiangxi
n/a
4th month (May 2–May 31, 1601 AD)

Korea (State)
Abnormally hot and wet
7th month (July 29–August 27, 1601 AD)

Guizhou (Province)
Drought
7th month (July 29–August 27, 1601 AD)

Shitai, Anhui
Abnormally cold and then abnormally hot
7-8th month (July 29–September 1601 AD)

Wuzhen, Zhejiang
Abnormally cold and then abnormally hot
7–9th month (July 29–October 25, 1601 AD)

Hangzhou, Zhejiang
Abnormally cold and then abnormally hot
7–9th month (July 29–October 25, 1601 AD)

Huzhou, Zhejiang
Abnormally cold and then abnormally hot
7–9th month (July 29–October 25, 1601 AD)

Tongxiang, Zhejiang
Abnormally cold and then abnormally hot
7–9th month (July 29–October 25, 1601 AD)

Nanxun, Zhejiang
Abnormally cold and then abnormally hot
7–9th month (July 29–October 25, 1601 AD)

Xinhua, Hunan
n/a
Autumn (7th–9th month, i.e., July 29–October 25, 1601 AD)

Dingxiang, Shanxi
Drought
Autumn (7th–9th month, i.e., July 29–October 25, 1601 AD)

Xingguo, Jiangxi
Drought
n/a

Qingxu, Shanxi
Drought
n/a

Linyou, Shaanxi
Drought
n/a

Yangqu, Shanxi
n/a
n/a

In Chinese and Korean historical literatures, particularly histories, chronicles and gazetteers, spring refers to the 1st–3rd months of the Chinese lunar calendar, and summer, autumn, and winter refer to the 4th–6th, 7th–9th, and 10th–12th months, respectively.

Figure 1: Abrupt cooling in 1601 AD in China and Korea. Dots denote records of abrupt cooling and epidemics, and different dots denote different seasons. Squares denote sites of relevant tree ring chronologies.

Figure 2: Epidemics in 1601 AD in China and Korea. Capitalized place names are Korea and provinces of China.

Figure 3: Seasonal variation of the number of records of epidemic in 1601 AD in southern China, northern China, and Korea.

The contemporary record of the abnormal weather in the summer and autumn of 1601 AD was found in a book titled Notes on Experience (Jian wen za ji) (Figure 1). The book is actually a diary, and it was finished in circa AD 1610 by Le Li, a retired scholar and official. (Le Li, Jian wen za ji. This book was written in circa 1610 AD. Here “Le” is the given name, and “Li” is the surname. Similarly hereinafter.) Le Li lived in Wuzhen (a town in Tongxiang County, Zhejiang Province) after retirement; thus the location of most of the events in the book was Wuzhen, including the record of the abnormal weather in 1601 AD.

This record is seen as the most original record of the epidemic and abnormal weather of 1601 AD, whereas similar descriptions of the event are also found in the local gazetteers of a few regions of Zhejiang Province. These regions include Hangzhou and Huzhou Prefectures (modern Hangzhou and Huzhou Cities) and Tongxiang County and Nanxun Town (modern Nanxun County of Huzhou City) (Table 1).

However, the descriptions in the Gazetteer of Shidai County (modern Shitai County, Anhui Province) and Gazetteer of Songjiang Prefecture (modern Songjiang County, Shanghai Municipality) are different from that of the Notes on Experience and should be independent from it. It is also worth noting that these two literatures were written a few decades later than the Notes on Experience (Table 1).

The spatial scale of the epidemics proved to be even larger than anticipated. We identified a plethora of records on epidemic outbreaks in 1601 AD in Anhui, Zhejiang, Fujian, Jiangxi, Hunan, and Guizhou Provinces of southern China (Figure 2). Some records indicated that the epidemics were related to drought and famine, whereas the causal link with abrupt cooling caused by the Huaynaputina event is not very clear (Table 1).

Separate from the above evidence, records were also found which described abrupt cooling which occurred in Kunming City (Yunnan Province). There was an abnormal snowfall in the autumn of 1601 AD in the area (Chengxun Fan and Jiwen Wang, General Gazetteer of Yunnan Province (Yunnan tong zhi) (1691), Vol. 28).

5. Abrupt Cooling and Epidemics in 1601 AD in Northern China

5.1. Historical Records

Our previous research has suggested that there were severe killing frosts in the Shanxi and Hebei Provinces in the summer and early autumn of 1601 AD (Fei and Zhou, 2009) [67]. Here we further supplemented our material with the records from Shaanxi, Gansu, and Qinghai Provinces and discovered that epidemics occurred in Shanxi and Shaanxi Provinces in 1601-1602 AD (Figures 1, 2, and 3; Tables 2 and 4). The epidemics in Shanxi and Shaanxi Provinces were possibly caused by a combination of killing frosts and drought. Supporting this information is the appearance of severe killing frosts and great epidemics in northern China in the summer and autumn of 1601 AD (Figures 1, 2, and 3; Tables 2 and 4).

It is noteworthy that killing frosts in the summer and autumn of 1601 AD in northern China were the result of outbreaks of cold waves that usually cover a large area. In some counties with records of epidemics, but without records of frost disasters (e.g., Yangqu, Qingxu Counties, and Shanxi Province), it is highly probable that frost disasters also occurred in these counties if there were killing frosts in the surrounding areas.

In addition, we identified a record of disease outbreaks in early 1601 AD. In the early spring of 1601 AD, excessive snows hit Xincai County (Henan Province) and resulted in the outbreak and rapid spread of disease (Tables 2 and 4; Figures 1 and 2).

The epidemics ended in 1601 AD in China, except in the Lishi County (Shanxi Province, Table 2), where disease outbreaks were reported again in the spring of 1602 AD. There were no further signs or data of widespread abrupt cooling and epidemics after 1602 AD.

5.2. Dendrochronology Records on the Northeast Tibetan Plateau

Past dendrochronological analyses were shown to be an exceptional source of information for tracking potential periods of dramatic or abrupt cooling and abnormal weather patterns. In addition, a few rigidly dated tree ring chronologies have been developed, which reveal past temperature changes on the northeast Tibetan Plateau, China (Figure 1).

Liu et al. (2005) reconstructed the winter half-year (prior December to current April) temperature change history of Sunan County (99°56′E, 38°26′N), Gansu Province, northeast Tibetan Plateau [69]. Zhu et al. (2008) established a tree ring width chronology at Wulan County (98°40′E, 37°03′N), Qinghai Province, thus reconstructing the winter half-year (prior September to current April) temperature change history over the past 1000 years in this region [70]. Liu et al. (2009, 2011) established a new chronology of annual temperature change over the past 2485 years at Dulan and Wulan Counties (98-99°E, 36-37°N), Qinghai Province, east Tibetan Plateau [71, 72].

However, 1601-1602 AD was not abnormally cold or warm in these three chronological records.

6. Abrupt Cooling and Epidemics in Korea

After a careful literature survey, we identified a total of three records on abnormal weather and disease outbreaks in Korea in 1601 AD (Tables 3 and 4; Figures 1 and 2). Accordingly, the spring and early summer of 1601 AD were anomalously gloomy and cold. The middle summer was hot and wet, with a resulting epidemic ensuing in the prevalent conditions of the time.

7. Discussion

According to the records with detailed dates, we identify a very interesting phenomenon in many areas of China and Korea; that is, most of the epidemics occurred in the summer and autumn (Table 4, Figure 3). The areas include the Korean Peninsula and the provinces of Zhejiang, Anhui, Shanxi, Guizhou, and Hunan in China (Figure 2). The epidemics were recorded simultaneously with the abnormal weather patterns, thus indicating a weather background and a possible causal link.

However, if the epidemics were related to the anomalous weather background, why did the epidemics break out almost simultaneously in different weather backgrounds (Table 4, Figure 3)? In Korea, the background was abnormally hot and wet weather. In Zhejiang and Anhui Provinces, the background was an abnormally cold July and a hot autumn. In Guizhou and Shanxi Provinces, the background was drought (Table 4). In Hunan province, the weather background was unidentified (Table 4).

With regard to the spatial distribution for the spread of endemic diseases, it is interesting that Korea, Zhejiang and Anhui Provinces, Shanxi Province, Guizhou, and Hunan Province are thousands of kilometres apart from each other (Figure 2). The epidemics in these four regions should be independent of one another. That is to say, weather backgrounds were different, and regions were independent; however, the records correlate multiple epidemics breaking out almost simultaneously across these regions.

It may seem to be overreaching to directly attribute the potential cause of these disease outbreaks to the 1600 AD Huaynaputina eruption. However, because the eruption reduced solar insolation and resulted in global abrupt cooling, it is not reasonable to exclude it as one of the major causes of the epidemics in China and Korea in August, September, and October, 1600 AD. In other words, while investigating the possible causes of the epidemics, the effects of the Huaynaputina eruption should not be neglected.

8. Conclusion

Historical records on the abrupt cooling and epidemics in 1601 AD in China and Korea were investigated, and its causal relationship with the 1600 AD Peruvian Huaynaputina eruption is discussed. We suggest that abrupt cooling occurred in 1601 AD in China and Korea following the Huaynaputina eruption. Near, thereafter, widespread epidemics occurred in the summer and autumn of 1601 AD in China and Korea.

There were severe killing frosts in the summer and autumn of 1601 AD in Shanxi, Hebei, Shaanxi, and Gansu Provinces of northern China, as well as an unseasonable snow in that summer in Hebei Province.

In Zhejiang and Anhui Provinces, and Shanghai Municipality in southern China, July of 1601 AD was abnormally cold with unseasonable snows, differentiated from August, September, and October which were abnormally hot. There were widespread epidemics following this anomalous weather. Simultaneously, disease outbreaks also occurred in Guizhou and Hunan Provinces.

In Korea, the spring and early summer of 1601 AD were abnormally cold; however, middle summer was hot and wet, which was followed by epidemics.

It is worth further discussion that widespread epidemics occurred almost simultaneously in Korea and the Chinese provinces of Zhejiang, Anhui, Guizhou, Hunan, and Shanxi. Apparently, the weather background of the epidemics was different; however, we suppose that the Huaynaputina eruption possesses a major burden of responsibility for these concurrent epidemic outbreaks.

Conflict of Interests

The authors declare that there is no conflict of interests regarding the publication of this paper.

Acknowledgments

The authors gratefully acknowledge support from the National Natural Science Foundation of China (Grant no. 41202125) and the Chinese Academy of Sciences (Grant no. KLSLRC-KF-13-DX-4). Special thanks are due to Professor Clive Oppenheimer and the anonymous reviewers for the constructive comments and suggestions.

References

H. H. Lamb, “Volcanic dust in the atmosphere; with a chronology and assessment of its meteorological significance,” Philosophical Transactions of the Royal Society of London A, vol. 266, pp. 425–533, 1970.

P. M. Kelly and C. B. Sear, “Climatic impact of explosive volcanic eruptions,” Nature, vol. 311, no. 5988, pp. 740–743, 1984.

C. B. Sear, P. M. Kelly, P. D. Jones, and C. M. Goodess, “Global surface-temperature responses to major volcanic eruptions,” Nature, vol. 330, no. 6146, pp. 365–367, 1987.

R. B. Stothers, “Volcanic dry fogs, climate cooling, and plague pandemics in Europe and the Middle East,” Climatic Change, vol. 42, no. 4, pp. 713–723, 1999.

D. K. Chester, M. Degg, A. M. Duncan, and J. E. Guest, “The increasing exposure of cities to the effects of volcanic eruptions: a global survey,” Environmental Hazards, vol. 2, no. 3, pp. 89–103, 2000.

A. Robock, “Volcanic eruptions and climate,” Reviews of Geophysics, vol. 38, no. 2, pp. 191–219, 2000.

G. A. Zielinski, “Use of paleo-records in determining variability within the volcanism-climate system,” Quaternary Science Reviews, vol. 19, no. 1–5, pp. 417–438, 2000.

W. S. Atwell, “Volcanism and short-term climatic change in East Asian and World history, c. 1200–1699,” Journal of World History, vol. 12, no. 1, pp. 29–98, 2001.

M. P. McCormick, L. W. Thomason, and C. R. Trepte, “Atmospheric effects of the Mt Pinatubo eruption,” Nature, vol. 373, no. 6513, pp. 399–404, 1995.

A. Robock, “Pinatubo eruption: the climatic aftermath,” Science, vol. 295, no. 5558, pp. 1242–1244, 2002.

S. Self and M. R. Rampino, “The 1883 eruption of Krakatau,” Nature, vol. 294, no. 5843, pp. 699–704, 1981.

R. B. Stothers and M. R. Rampino, “Volcanic eruptions in the Mediterranean before A.D. 630 from written and archaeological sources,” Journal of Geophysical Research, vol. 88, no. 8, pp. 6357–6371, 1983.

R. B. Stothers, “The great Tambora eruption in 1815 and its aftermath,” Science, vol. 224, no. 4654, pp. 1191–1198, 1984.

R. B. Stothers, “Cloudy and clear stratospheres before A.D. 1000 inferred from written sources,” Journal of Geophysical Research, vol. 107, no. D23, article 4718, 2002.

K. D. Pang, “Climatic impact of the mid-fifteenth century Kuwae caldera formation, as reconstructed from historical and proxy data,” Eos, vol. 74, p. 106, 1993.

C. Oppenheimer, “Climatic, environmental and human con sequences of the largest known historic eruption: Tambora volcano (Indonesia) 1815,” Progress in Physical Geography, vol. 27, no. 2, pp. 230–259, 2003.

J. B. Witter and S. Self, “The Kuwae (Vanuatu) eruption of AD 1452: potential magnitude and volatile release,” Bulletin of Volcanology, vol. 69, no. 3, pp. 301–318, 2007.

P. Y. Forsyth, “In the wake of Etna, 44 B.C,” Classical Antiquity, vol. 7, no. 1, pp. 49–57, 1988.

P. J. Bicknell, “Blue suns, the son of heaven, and the chronology of the volcanic veil of the 40s B.C.,” The Ancient History Bulletin, vol. 7, pp. 2–11, 1993.

S. Cao, Y. Li, and B. Yang, “Mt. tambora, climatic changes, and China's decline in the nineteenth century,” Journal of World History, vol. 23, no. 3, pp. 587–607, 2012.

J. Fei and J. Zhou, “The possible climatic impact in China of Iceland's Eldgjá eruption inferred from historical sources,” Climatic Change, vol. 76, no. 3-4, pp. 443–457, 2006.

C. F. Mass and D. A. Portman, “Major volcanic eruptions and climate: a critical assessment,” Journal of Climate, vol. 2, no. 6, pp. 566–593, 1989.

M. E. Mann, M. A. Cane, S. E. Zebiak, and A. Clement, “Volcanic and solar forcing of the tropical Pacific over the past 1000 years,” Journal of Climate, vol. 18, no. 3, pp. 447–456, 2005.

C. Shen, W.-C. Wang, Z. Hao, and W. Gong, “Characteristics of anomalous precipitation events over eastern China during the past five centuries,” Climate Dynamics, vol. 31, no. 4, pp. 463–476, 2008.

C. Shen, W.-C. Wang, Z. Hao, and W. Gong, “Exceptional drought events over eastern China During the last five centuries,” Climatic Change, vol. 85, no. 3-4, pp. 453–471, 2007.

A. Hansell and C. Oppenheimer, “Health hazards from volcanic gases: a systematic literature review,” Archives of Environmental Health, vol. 59, no. 12, pp. 628–639, 2004.

N. Floret, J.-F. Viel, F. Mauny, B. Hoen, and R. Piarroux, “Negligible risk for epidemics after geophysical disasters,” Emerging Infectious Diseases, vol. 12, no. 4, pp. 543–548, 2006.

C. J. Horwell and P. J. Baxter, “The respiratory health hazards of volcanic ash: a review for volcanic risk mitigation,” Bulletin of Volcanology, vol. 69, no. 1, pp. 1–24, 2006.

C. S. Witham and C. Oppenheimer, “Mortality in England during the 1783–4 Laki Craters eruption,” Bulletin of Volcanology, vol. 67, no. 1, pp. 15–26, 2004.

J. Grattan, “Pollution and paradigms: lessons from Icelandic volcanism for continental flood basalt studies,” Lithos, vol. 79, no. 3-4, pp. 343–353, 2005.

J. Grattan, R. Rabartin, S. Self, and T. Thordarson, “Volcanic air pollution and mortality in France 1783–1784,” Comptes Rendus Geoscience, vol. 337, no. 7, pp. 641–651, 2005 (French).

S. L. de Silva and G. A. Zielinski, “Global influence of the AD 1600 eruption of Huaynaputina, Peru,” Nature, vol. 393, no. 6684, pp. 455–458, 1998.

J.-C. Thouret, J. Davila, and J.-P. Eissen, “Largest explosive eruption in historical times in the Andes at Huaynaputina volcano, A.D. 1600, southern Peru,” Geology, vol. 27, no. 5, pp. 435–438, 1999.

J.-C. Thouret, E. Juvigné, A. Gourgaud, P. Boivin, and J. Dávila, “Reconstruction of the AD 1600 Huaynaputina eruption based on the correlation of geologic evidence with early Spanish chronicles,” Journal of Volcanology and Geothermal Research, vol. 115, no. 3-4, pp. 529–570, 2002.

Y. Lavallée, S. L. De Silva, G. Salas, and J. M. Byrnes, “Explosive volcanism (VEI 6) without caldera formation: insight from Huaynaputina volcano, southern Peru,” Bulletin of Volcanology, vol. 68, no. 4, pp. 333–348, 2006.

K. Verosub and J. Lippman, “Global impacts of the 1600 eruption of Peru's huaynaputina volcano,” Eos, vol. 89, no. 15, pp. 141–143, 2008.

N. K. Adams, S. L. De Silva, S. Self et al., “The physical volcanology of the 1600 eruption of Huaynaputina, southern Peru,” Bulletin of Volcanology, vol. 62, no. 8, pp. 493–518, 2001.

S. L. De Silva, J. Alzueta, and G. Salas, “The socioeconomic consequences of the 1600 AD eruption of Huaynaputina,” in Volcanic Hazards and Human Antiquity, G. Heiken and F. McCoy, Eds., Special Paper 345 of the Geological Society of America, pp. 15–24, The Geological Society of America, Boulder, Colo, USA, 2000.

R. Navarro Oviedo, L. A. Jara, J.-C. Thouret, C. Siebe, and J. Dávila, “The AD 1600 eruption of Huaynaputina as described in early Spanish gazetteers,” Boletín de la Sociedad Geológica del Perú, vol. 90, pp. 121–132, 2000.

F. Costa, B. Scaillet, and A. Gourgaud, “Massive atmospheric sulfur loading of the AD 1600 Huaynaputina eruption and implications for petrologic sulfur estimates,” Geophysical Research Letters, vol. 30, no. 2, p. 1068, 2003.

S. Self, R. Gertisser, T. Thordarson, M. R. Rampino, and J. A. Wolff, “Magma volume, volatile emissions, and stratospheric aerosols from the 1815 eruption of Tambora,” Geophysical Research Letters, vol. 31, no. 20, Article ID L20608, 2004.

C. Gao, L. Oman, A. Robock, and G. L. Stenchikov, “Atmospheric volcanic loading derived from bipolar ice cores: accounting for the spatial distribution of volcanic deposition,” Journal of Geophysical Research: Atmospheres, vol. 112, no. 9, Article ID D09109, 2007.

R. J. Delmas, S. Kirchner, J. M. Palais, and J.-R. Petit, “1000 Years of explosive volcanism recorded at the South Pole,” Tellus, vol. 44, no. 4, pp. 335–350, 1992.

J. M. Palais, S. Kirchner, and R. J. Delmas, “Identification of some global volcanic horizons by major element analysis of fine ash in Antarctic ice,” Annals of Glaciology, vol. 14, pp. 216–220, 1990.

C. U. Hammer, H. B. Clausen, and W. Dansgaard, “Greenland ice sheet evidence of post-glacial volcanism and its climatic impact,” Nature, vol. 288, no. 5788, pp. 230–235, 1980.

T. J. Crowley, T. A. Criste, and N. R. Smith, “Reassessment of Crete (Greenland) ice core acidity/volcanism link to climate change,” Geophysical Research Letters, vol. 20, no. 3, pp. 209–212, 1993.

H. B. Clausen, C. U. Hammer, S. Hvidberg et al., “A comparison of the volcanic records over the past 4000 years from the Greenland Ice Core Project and Dye 3 Greenland ice cores,” Journal of Geophysical Research, vol. 102, no. 12, pp. 26707–26723, 1997.

S. J. Johnsen, H. B. Clausen, W. Dansgaard et al., “Irregular glacial interstadials recorded in a new Greenland ice core,” Nature, vol. 359, no. 6393, pp. 311–313, 1992.

G. A. Zielinski, P. A. Mayewski, L. D. Meeker et al., “Record of volcanism since 7000 B.C. from the GISP2 Greenland ice core and implications for the volcano-climate system,” Science, vol. 264, no. 5161, pp. 948–952, 1994.

A. S. Palmer, T. D. van Ommen, M. A. J. Curran, V. Morgan, J. M. Souney, and P. A. Mayewski, “High-precision dating of volcanic events (A.D. 1301-1995) using ice cores from Law Dome, Antarctica,” Journal of Geophysical Research: Atmospheres, vol. 106, no. 22, pp. 28089–28095, 2001.

J. Cole-Dai, E. Mosley-Thompson, S. P. Wight, and L. G. Thompson, “A 4100-year record of explosive volcanism from an East Antarctica ice core,” Journal of Geophysical Research: Atmospheres, vol. 105, no. 19, pp. 24431–24441, 2000.

D. Budner and J. Cole-Dai, “The number and magnitude of large explosive volcanic eruptions between 904 and 1865 A.D.: quantitative evidence from a new South Pole ice core,” Geophysical Monograph, vol. 139, pp. 165–176, 2003.

B. Stenni, M. Proposito, R. Gragnani et al., “Eight centuries of volcanic signal and climate change at Talos Dome (East Antarctica),” Journal of Geophysical Research, vol. 107, no. 9, p. 4076, 2002.

M. Igarashi, Y. Nakai, Y. Motizuki, K. Takahashi, H. Motoyama, and K. Makishima, “Dating of the Dome Fuji shallow ice core based on a record of volcanic eruptions from AD 1260 to AD 2001,” Polar Science, vol. 5, no. 4, pp. 411–420, 2011.

K. R. Briffa, P. D. Jones', F. H. Schweingruber, and T. J. Osborn, “Influence of volcanic eruptions on Northern Hemisphere summer temperature over the past 600 years,” Nature, vol. 393, no. 6684, pp. 450–455, 1998.

L. A. Scuderi, “Tree-ring evidence for climatically effective volcanic eruptions,” Quaternary Research, vol. 34, no. 1, pp. 67–85, 1990.

P. D. Jones, K. R. Briffa, and F. H. Schweingruber, “Tree-ring evidence of the widespread effects of explosive volcanic eruptions,” Geophysical Research Letters, vol. 22, no. 11, pp. 1333–1336, 1995.

U. Büntgen, J. Esper, D. C. Frank, K. Nicolussi, and M. Schmidhalter, “A 1052-year tree-ring proxy for Alpine summer temperatures,” Climate Dynamics, vol. 25, no. 2-3, pp. 141–153, 2005.

R. D. D'Arrigo and G. C. Jacoby, “Northern North American tree-ring evidence for regional temperature changes after major volcanic events,” Climatic Change, vol. 41, no. 1, pp. 1–15, 1999.

M. Génova, “Extreme pointer years in tree-ring records of Central Spain as evidence of climatic events and the eruption of the Huaynaputina Volcano (Peru, 1600 AD),” Climate of the Past, vol. 8, no. 2, pp. 751–764, 2012.

V. C. LaMarche Jr. and K. K. Hirschboeck, “Frost rings in trees as records of major volcanic eruptions,” Nature, vol. 307, no. 5947, pp. 121–126, 1984.

L. Filion, S. Payette, L. Gauthier, and Y. Boutin, “Light rings in subarctic conifers as a dendrochronological tool,” Quaternary Research, vol. 26, no. 2, pp. 272–279, 1986.

D. K. Yamaguchi, L. Filion, and M. Savage, “Relationship of temperature and light ring formation at subarctic treeline and implications for climate reconstruction,” Quaternary Research, vol. 39, no. 2, pp. 256–262, 1993.

R. M. Hantemirov, L. A. Gorlanova, and S. G. Shiyatov, “Extreme temperature events in summer in northwest Siberia since AD 742 inferred from tree rings,” Palaeogeography, Palaeoclimatology, Palaeoecology, vol. 209, no. 1–4, pp. 155–164, 2004.

D. M. Pyle, “How did the summer go?” Nature, vol. 393, no. 6684, pp. 415–417, 1998.

G. Utterström, “Climatic fluctuations and population problems in early modern history,” Scandinavian Economic History Review, vol. 3, pp. 26–41, 1955.

J. Fei and J. Zhou, “The possible climatic impact in North China of the AD 1600 Huaynaputina eruption, Peru,” International Journal of Climatology, vol. 29, no. 6, pp. 927–933, 2009.

Beijing Astronomical Observatory and Chinese Academy of Sciences, A Joint Catalogue of the Chinese Local Chronicles, The Chinese Press (Zhonghua Shuju), Beijing, China, 1985 (Chinese).

X. Liu, D. Qin, X. Shao, T. Chen, and J. Ren, “Temperature variations recovered from tree-rings in the middle Qilian Mountain over the last millennium,” Science in China, Series D: Earth Sciences, vol. 48, no. 4, pp. 521–529, 2005.

H. Zhu, Y. Zheng, X. Shao, X. Liu, Y. Xu, and E. Liang, “Millennial temperature reconstruction based on tree-ring widths of Qilian juniper from Wulan, Qinghai Province, China,” Chinese Science Bulletin, vol. 53, no. 24, pp. 3914–3920, 2008.

Y. Liu, Z. An, H. W. Linderholm et al., “Annual temperatures during the last 2485 years in the mid-eastern tibetan plateau inferred from tree rings,” Science in China, Series D: Earth Sciences, vol. 52, no. 3, pp. 348–359, 2009.

Y. Liu, Q. Cai, H. Song, Z. An, and H. W. Linderholm, “Amplitudes, rates, periodicities and causes of temperature variations in the past 2485 years and future trends over the central-eastern Tibetan Plateau,” Chinese Science Bulletin, vol. 56, no. 28-29, pp. 2986–2994, 2011.