Historical Droughts in the Qing Dynasty (1644–1911) of China
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Clim. Past, 16, 911–931, 2020 https://doi.org/10.5194/cp-16-911-2020 © Author(s) 2020. This work is distributed under the Creative Commons Attribution 4.0 License. Historical droughts in the Qing dynasty (1644–1911) of China Kuan-Hui Elaine Lin1, Pao K. Wang2,3, Pi-Ling Pai4, Yu-Shiuan Lin2, and Chih-Wei Wang2 1Graduate Institute of Environmental Education, National Taiwan Normal University, Taipei, Taiwan 2Research Center for Environmental Changes, Academia Sinica, Taipei, Taiwan 3Department of Atmospheric and Oceanic Sciences, University of Wisconsin–Madison, Madison, Wisconsin, USA 4Research Center for Humanities and Social Sciences, Academia Sinica, Taipei, Taiwan Correspondence: Kuan-Hui Elaine Lin ([email protected]) and Pao K. Wang ([email protected]) Received: 31 August 2019 – Discussion started: 7 October 2019 Revised: 17 March 2020 – Accepted: 8 April 2020 – Published: 2 June 2020 Abstract. This study presents a new epistemological analy- 1 Introduction sis of drought chronology through a well-defined methodol- ogy for reconstructing past drought series, as well as series Global warming is expected to influence the earth’s hydro- of other associated ecological and societal impact variables. logical cycle and put greater stress on water resources. Cli- Instead of building a grading system based on mixed crite- mate simulations reveal a wide expansion of dry areas over ria, this method facilitates transparency in the reconstruction land and an intensification of wet–dry contrast at lower lat- process and enables the statistical examination of all vari- itudes (Held and Soden, 2006; Schewe et al., 2014). There ables when building series. The data for the present study are some recent observations that hint at the agreement with are derived mainly from the REACHES (Reconstructed East the projected enlarging wet–dry contrast pattern and intensi- Asian Climate Historical Encoded Series) database; however, fied drought (Schewe et al., 2014), although substantial un- other archival documentary and index data from indepen- certainties about specific patterns and trends remain. Even dent sources are also applied to understand drought narra- less understood is the interannual- and decadal-scale change tives and to cross-check and validate the analysis derived patterns of regional precipitation and the duration and mag- from REACHES. From the time series analysis, six severe nitude of drought at finer spatial and temporal resolutions drought periods are identified in the Qing dynasty, and then (IPCC, 2013). Obviously, more high-quality hydroclimate a spatial analysis is performed to demonstrate the spatial dis- data are necessary if we wish to remove these uncertainties. tribution of drought and other variables in the six periods, as Such data are also necessary for assessing the performance well as a social network analysis to reveal connections be- of climate models, especially on their capability in project- tween drought and other ecological and societal variables. ing reliably the climates of the next few decades. The length Research results clearly illustrate the role of human interven- of the instrumental meteorological data series is only a little tion in influencing the impacts of drought and their societal more than a hundred years, which is not long enough to as- consequences. Particularly, the correlation between drought sess the validity of climate models that make predictions for and socioeconomic turmoil is not strong; crop failure and many decades into the future (Cook et al., 2014; Ljungqvist famine are important intermediate factors, while ecological et al., 2016). factors such as locust and disaster relief measures are all im- The most direct manifestation of hydroclimate variabil- perative to intervene between crop production and famine. ity is drought and the flooding of the environment (Routson Implications of the study on drought impact are provided, as et al., 2016; Stevenson et al., 2018). Drought and flood are well as the significance of drought on historical climate re- two extremes of the hydrological cycle, and both can induce construction studies. severe environmental and socioeconomic consequences. A flood, which generally represents the sudden onset of ex- cessive water, can lead to immediate loss of lives and ma- terial damages. The formation of drought, on the contrary, Published by Copernicus Publications on behalf of the European Geosciences Union. 912 K.-H. E. Lin et al.: Historical droughts in the Qing dynasty normally refers to a slower and longer water deficiency pro- et al., 2019). To be sure, there are also some criticisms cess that can result in a more chronologically extended range about inferring drought from documented records; for exam- of impacts on agriculture and water scarcity, contributing to ple, it is sometimes hard to distinguish whether the drought catastrophic socioeconomic outcomes (Brázdil et al., 2019). record refers to a rainfall deficiency, hydrological process, or Given the intensified drought conditions in the future sce- crop irrigation need. Several studies tried to remedy this by narios as described above, there is an urgent need to study proposing four categories of drought: meteorological drought past droughts, especially the severe drought cases, to deci- caused by significant reduction of precipitation for weeks pher their occurrence, duration, magnitude, and the associ- or months compared to normal precipitation; agricultural ated ecological and societal consequences for implications drought associated with lack of water for plant growth for of future adaptation. a period lasting from weeks to 6–9 months; hydrological Studying past drought and humidity has been a long prac- drought characterized by a shortage or absence of water in ticed subject in historical climatology and paleoclimatology water courses, reservoirs, or aquifers; and socioeconomic (Stahle et al., 2007; Tan and Liao, 2012; Yi et al., 2012; Cook drought caused by the negative effect of drought on every- et al., 2015; Ge et al., 2016; Hao et al., 2016; Brázdil et al., day life, social systems, and stability (Heim, 2002; Brázdil et 2018; Shi et al., 2018). In the instrumental era, drought is al., 2018). There is yet another view suggesting that drought relatively easy to define based on temperature and precip- is a complicated process of water shortage caused and mod- itation measurements. The instrumental era can be traced ified by human processes (Van Loon et al., 2016). Despite back to the mid or late 19th century, when many national such shortages, documentary records are still one of the most weather services started (Broennimann et al., 2018). Some important sources for reconstructing drought series, only we early instrumental meteorological data might be acquired in have to be very careful in extracting proper information from some regions, dating back to the late 17th and early 18th them. centuries. Prior to the instrumental era, there were primarily Brázdil et al. (2018) have described various types of doc- two sources of data that can be used to build drought series umentary records that can be used for extracting drought in- of high temporal resolution: tree-ring data and documentary formation. Before the instrumental era, all historical climate records (White, 2019). Tree rings provide abundant informa- records were essentially qualitative or narrative in nature, and tion about moisture, and sometimes temperature, for recon- it is necessary to transform them into numerical data series so structing millennial-long hydroclimate indices from which that statistical analysis of them can be performed. The most drought can be inferred. The most well-known works in- common practice is to design a three-, five- or seven-grade clude the Old World Drought Atlas (Cook et al., 2015), system based on the duration and severity of drought (Zheng which uses tree-ring data and is calibrated with the Palmer et al., 2014; Brázdil et al., 2018) so that every single quota- Drought Severity Index (PDSI) (Palmer, 1965), the Monsoon tion of drought recorded can be assigned a specific value ac- Asia Drought Atlas (Cook et al., 2010), and “Tree-ring re- cording to the grading criteria. By arranging these grades as a constructed megadroughts over North America since A.D. sequence in time, we get a time series of drought grade, often 1300” (Stahle et al., 2007). Yet, tree-ring reconstruction often called a drought index series. In reality, however, the trans- suffers from the uncertainty in the seasonal growth of trees formation process from qualitative narratives to digital series and the ambiguous interpretation of isotopes (Schofield et can be tricky because a wide spectrum of grade assignment al., 2016). Nonetheless, high-quality quantitative drought in- strategy exists and different investigators can derive very dif- dex series, such as the Standardized Precipitation Index (SPI) ferent index series based on the same set of drought records. (Mckee et al., 1993), the Standardized Precipitation Evap- More detailed discussions on this matter have been given by otranspiration Index (SPEI) (Vicente-Serrano et al., 2010), Brázdil et al. (2005) and Pfister et al. (1999). the PDSI, and the Palmer Z-Index, can also be reconstructed In China, a dryness–wetness (also referred to as drought– from documentary data. For example, Brázdil et al. (2016) flood) index has been widely used in recent decades for re- and Možný et al. (2016) have built monthly, seasonal, half- constructing past climates (Tan and Liao, 2012; Yi et al.,