SYLLABUS

GS-1: Salient features of world’s physical geography.

Context: A palaeoclimate study using lake sediment pollen from Central India reveals that the Indian Summer Monsoon was significantly stronger during the Medieval Climate Anomaly.

More on the News

• Scientists have discovered evidence of intensified Indian Summer Monsoon rainfall between 1060 and 1725 CE by extracting a 40-centimetre-long sediment core from the Raja Rani Lake in Korba district, Chhattisgarh.
• The study pertaining to the Late Holocene (Meghalayan Age), a period marked by significant monsoon variability, was conducted by researchers from the Birbal Sahni Institute of Palaeosciences (BSIP), Lucknow, an autonomous institute under the Department of Science and Technology (DST).
  • The Meghalayan Age is the most recent stage of the Holocene Epoch that begins nearly 4,200 years before present, and was officially recognised by the International Commission on Stratigraphy (ICS) in 2018.
• The findings were published in the January issue of the journal Review of Palaeobotany and Palynology.

Key Findings of the Study

• Stronger Monsoon in Past: The pollen record strongly indicates that the Indian Summer monsoon (ISM) was much stronger between roughly 1060 CE and 1725 CE, particularly during the Medieval Climate Anomaly (MCA).
  • The Medieval Climate Anomaly (MCA) also called the Medieval Warm Period, was a climatic phase roughly between AD 950 and 1250 when many parts of the world experienced warmer-than-average temperatures, along with regional changes in rainfall patterns.
• Reconstructed past vegetation: During the MCA, the pollen record showed a clear dominance of moist and dry tropical deciduous forest species, indicating strong monsoon rainfall and a warm, humid climate in central India. 
• Absence of drier phase: No evidence of contrasting dry conditions within the Core Monsoon Zone during the period.
  • The Core Monsoon Zone (CMZ) is a climatologically defined region of India that receives the most consistent and significant rainfall from the Southwest (summer) Monsoon.
• Multiple factors in enhancing monsoon: combination of global and regional factors like La-Niña, northward movement of the Intertropical Convergence Zone (ITCZ), positive temperature anomalies, increased sunspot numbers and high solar activity could be driving the climate change and increased ISM during the MCA.
  • The Intertropical Convergence Zone (ITCZ) is a low-pressure belt near the Equator where the northeast and southeast trade winds converge, causing intense convection, cloud formation, and heavy rainfall.

Significance of the findings

• Strengthen present Climatic understanding: The study of ISM and related climate change variability during the Holocene could be of immense interest to strengthen our understanding of the present ISM-influenced climatic conditions, as well as of possible future climatic trends and projections.
• Input for Climatic Model: high-resolution palaeoclimatic records generated in the present study could help develop paleoclimatic models for the simulation of future climatic trends and rainfall patterns, and also for a scientifically sound policy planning with a key aspect of societal relevance.

Source:
Tribune India
PIB
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