Vegetation response to the Indian Summer Monsoon (ISM) variability during the Late-Holocene from the central Indian core monsoon zone

Abstract

Pollen analysis and radiocarbon dating of a 1.4 m deep lacustrine sediment profile from Chhattisgarh State, central India, in the core monsoon zone (CMZ), has revealed the vegetation history, associated climate change and the Indian Summer Monsoon (ISM) rainfall variability during the Late-Holocene. The pollen evidence suggests that between ca. 3000 and 2600 cal year BP, tree-savannah vegetation occurred in the region having a comparatively lesser monsoon rainfall. The forest expanded and culminated into an open-mixed tropical deciduous forest between ca. 2600 and 2200 cal year BP under a warm and moderately humid climate with an increase in monsoon rainfall. Subsequently, between ca. 2200 and 2000 cal year BP, the existing open-mixed tropical deciduous forest transformed into a mixed tropical deciduous forest under a warm and humid climate with further increase in monsoon rainfall. Finally, between ca. 2000 and 1800 cal year BP, a dense mixed tropical deciduous forest occupied the landscape under a regime of a warm and relatively more humid climate with further strengthening of the ISM. The gradual warming, and the climatic amelioration with the intensification of the ISM, during the Late-Holocene (ca. 2600–1800 cal year BP; ~650 BC to AD150) corresponds to the Roman Warm Period (RWP), recorded globally between 2500 and1600 cal year BP (~550 BC to AD ~350). Human activities were present around the study area, which varied according to the ISM variations. The present study provides insights into the gradual intensification of the monsoon since the last ca. 2600 cal year BP (between ca. 2600 and1800 cal year BP), and an increase in the ISM strength in the CMZ of India, against the generally weakening trend during the Late-Holocene.

Monitoring hydroecology and climatic variability since ~4.6 ka from palynological, sedimentological and environmental perspectives in an Ox-bow lake, Central Ganga Plain, India

“…Holocene climatic variability in response to ISM has been recently reviewed over the Gangetic Plains through studies from several lake sedimentary profiles (Misra et al, 2020; Quamar and Kar, 2020a). The rise in temperature began both at higher and lower altitudes after ~10 ka until the cold spell ~8 ka (Achyuthan et al, 2016; Misra et al, 2019; Quamar et al, 2021). Broadly, moist conditions between 7 -6 ka and dry conditions since ~5 ka reached the climatic climax ~4.2 ka inducing extreme arid conditions which are also recorded the world over (Farooqui et al, 2013; Kathayat et al, 2017; Roy et al, 2022).…”

“…Several other records from India suggest a weakening of ISM ~4.2 ka (Berkelhammer et al, 2013; Dixit et al, 2014; Staubwasser et al, 2003). The period of last two millennium is known to have witnessed a series of short-spell warmer periods such as the Medieval Warm Period (MWP), the Roman Warm Period (RWP), and the Minoan Warm Period (MnWP) and known colder spells during the Little Ice Age (Achyuthan et al, 2016; Borzenkova et al, 2015; Quamar et al, 2021)). A negative coupling has been recorded between local soil moisture and precipitation indicating land-atmosphere relation over the Gangetic plains (Agrawal and Chakraborty, 2016).…”

Multiproxy studies on the spatially distinct surface samples to reconstruct palaeoecology and palaeoclimate from the Core Monsoon Zone of India

“…However, uneven land surfaces with deep gorges can also be seen. Hilly soils, red-yellow, red sandy soils, sandy soil and alluvial soils, as well as laterite soils, are found (Quamar, 2019;Quamar & Chauhan, 2012;Quamar & Bera, 2020;Quamar & Kar, 2020b;Quamar et al, 2021 and references cited therein). The sediment samples were collected from lakes and forests area in the geological settings of Deccan Basalt, Late Triassic to Upper Carboniferous sedimentary rocks and Precambrian rocks, lying roughly between 22º-23º latitude and 76º-84º longitudes.…”

Reconstructing the Climate Variability During the Last 5000 Years From the Banni Plains, Kachchh, Western India

“…Pillai et al (2018) from Luna core reported arid climatic condition during 3,000 to 2,500 years BP. Similarly, Quamar et al (2021) studied a lacustrine sequence from central India and based on the pollen study reported a decline in strength of ISM during 3,000 to 2,600 years BP period. Similarly studies from the mudflats of Diu, Gujarat, are suggestive of the arid conditions during 2, 640-1930cal yr BP (Banerjee et al, 2017.…”