Climate change stimulated agricultural innovation and exchange across Asia

Abstract

Agrarian societies reduced risk during pan-Asian cooling events by investing in pastoralism and developing long-distance trade.

Discontinuous spread of millet agriculture in eastern Asia and prehistoric population dynamics

“…The most frequently argued causes are changing climate conditions characterized by higher variability leading to more unstable environments and an enhanced trend toward lower temperatures and moisture availability related to the 4.2-kiloyear event and/or the continuous middle-late Holocene decline in Asian summer monsoon intensity ( 37 – 40 ). Although the importance of climatic conditions in the life of prehistoric farmers in China is frequently acknowledged ( 5 , 16 , 40 ), geoscientists and archaeologists still have difficulties in determining where, when, and how changes in climate affected the ancient population ( 41 ). Many of the published archaeological and paleoclimatic records often allow controversial interpretations due to the lack of high enough resolution and accurate dating ( 16 ).…”

“…A crop niche modeling study ( 41 ) demonstrates that in parts of the Tibetan Plateau and in higher-elevated regions of central Asia, climate cooling enhanced after 2000 BCE had a negative impact on the yields of millet and led agropastoralists to diversify their crops, introducing more cold-resistant wheat and barley. Although crop diversification after 2000 BCE is also documented in the archaeological record from northeastern China ( 5 , 18 ), the probability density of millet-based 14 C dates does not indicate a decrease in millet cultivation but suggests that millet continued to be a staple in the region during the second millennium BCE (Fig.…”

Early integration of pastoralism and millet cultivation in Bronze Age Eurasia

“…The subsequent decline in millet foddering during the Late Bronze Age is likely due to C 3 cultigens arriving via secondary crop dispersals [5], especially landraces of barley adapted to high altitudes [66]. From ca 1750–1000 cal BC, this diversification in cropping across Asia is also linked to reducing risks during climatic shifts towards cooler conditions [25]. However, improved palaeo-climate records are needed to characterize earlier periods.…”

Three thousand years of farming strategies in central Thailand

“…Today, the range of tropical O. japonica is limited to Southeast Asia and far southern China. In the warmer Early Holocene (before 2000 cal BC), however, this crop may have ranged as far as north-eastern China (d'Alpoim Guedes & Bocinsky 2018).…”

“…After 2000 cal BC, increasingly cooler temperatures led to a retreat of the area available for cultivating tropical varieties of O. japonica to south-eastern China and Southeast Asia (Figure 8). By 1590 cal BC, farmers of tropical rice varieties in both Yunnan and the Central Yangtze region would have already begun to experience difficulties in cultivating this crop (d'Alpoim Guedes & Bocinsky 2018;Gutaker et al 2020) (Figure 8). While large parts of Zhejiang and Hunan lost their suitability for tropical O. japonica, the higher-altitude Yunnan-Guizhou Plateau suffered the largest loss of area suitable for this type of rice.…”