A high-resolution, 1250-year long drought record from Ea Tyn Lake, Central Highlands of Việt Nam

Abstract

An understanding of past climatic variability at regional to local scales is mandatory for a proper evaluation of current and potential future repercussions from global climate change. The Southeast Asian tropics remain severely under-represented in paleoenvironmental and paleoclimatic reconstructions, although a few recent paleoclimate studies evaluated the variability, position and strength of the main Asian monsoon systems at different timescales from modern records to the last 15,000 years. Comparable data from Việt Nam, however, are scarce although Việt Nam and its Central Highlands are critically located at the intersection of the East Asian Summer Monsoon and the Indian Summer Monsoon with highly important socio-ecological consequences from changes in the climate system. This study presents a high-resolution sedimentary climate record from Ea Tyn Lake in Việt Nam’s Central Highlands covering the last 1250 years. Using geochemical and sedimentological proxies and principal component analysis, we reconstructed at least 12 drought events, some of which appear to be of supraregional significance as they coincide with historically documented droughts in India, China, and Cambodia. Beyond tracking short-term climate events, the Rb/Sr elemental ratio along the Ea Tyn Lake sediment sequence reflects long-term monsoon variability throughout the last millenium, which was previously only reconstructed via δ18O speleothem records from China and India. Our Ea Tyn Lake record shows that the East Asian Summer Monsoon was relatively strong between ~1000 and 1350 cal CE and weaker between 1350 and 1850 cal CE, followed by renewed intensification after ~1850 cal CE.

Diatom-based indications of an environmental regime shift and droughts associated with seasonal monsoons during the Holocene in Biển Hồ maar lake, the Central Highlands, Vietnam

“…Temporal correlation between the Biển Hồ diatom data and regional palaeoclimatic events. [a] (Ojala et al, 2023), [b] (Wang et al, 2012), [c] (Moy et al, 2002); [1,2,3] (Dykoski et al, 2005; Marcott et al, 2013); [2,3,5] (Smittenberg et al, 2022); [3,4] (Kaboth-Bahr et al, 2021); [4,6] (Wolf, 2022); [6,9] (Griffiths et al, 2020); [6] (Kajita et al, 2018; Pausata et al, 2017; Wolf et al, 2023); [7] (Nguyễn-Đình et al, 2022); [8] (Buckley et al, 2010, 2014). …”

“…granulata during the Late-Holocene indicates a weakening of the summer monsoon (Figure 6). Specifically, the lake water level declined between 700 and 400 cal BP (in DAZ 2C), coincided with severe drought events in mainland Southeast Asia, such as Angkor I & II Droughts (Buckley et al, 2010(Buckley et al, , 2014Nguyễn-Đình et al, 2022).…”

“…Two studies analysed diatom assemblages and geochemical proxies from Ba Bể lake (Weide, 2012) and Ao Tiên (Fairy Pond) (Stevens et al, 2018) to point out monsoonal characteristics in the karst region of Northern Vietnam over the last 500 and 650 years, respectively. In the Central Highlands, two recent studies from Ea Tyn lake (Nguyễn-Đình et al, 2022) and Biển Hồ lake (Nguyễn-Văn et al, 2022) covering the past 1250 and 70 years, respectively, have revealed substantial responses in sedimentary, geochemical, geophysical and microfossil proxies that are attributed to both anthropogenic influences and the impact of monsoon subsystems on the lake ecosystems.…”

“…The evolution of the summer and winter monsoon subsystems has grown progressively complex and diverse due to ongoing climate change since the Late Pleistocene and anthropogenic global warming (Li et al, 2014; Kaboth-Bahr et al, 2021; Wolf, 2022). These mechanisms have given rise to extreme climatic events, including droughts in the Central Highlands already in the past (Nguyễn-Đình et al, 2022), and also leading to significant agricultural losses with profound socio-economic repercussions on local communities in modern times (Asia-CRCiS, 2016).…”