Monsoon Fluctuation Footprints

Why in News?

A recent study published in the Journal of Asian Earth Sciences reconstructs approximately 4,600 years of climate and environmental history in the Central Ganga Plain.

• Sediments analysed from – Karela Lake (Hulas Khera), an oxbow lake near Lucknow, Uttar Pradesh.
• Aim – To investigate the impact of Indian Summer Monsoon variability on ecosystems and early agricultural communities.
• Conducted by – Birbal Sahni Institute of Palaeosciences (BSIP), an autonomous institute under the Department of Science and Technology (DST).
• Key Findings
  • Monsoon variability significantly affected lake water conditions and associated hydrological processes.
  • Variations in rainfall altered sediment transport, including changes in grain size and patterns of deposition.
  • Climatic fluctuations drove transitions between C₃ and C₄ vegetation types.

C3 and C4 plants use different biochemical pathways to fix carbon dioxide during photosynthesis.

• • Monsoon variability influenced both the composition and deposition of sedimentary organic matter.
  • Alterations in environmental conditions affected microbial activity within lake sediments.
  • Climatic changes influenced agricultural adaptation, including the adoption of manure-based farming practices.
  • Moisture records linked to westerly winds offered evidence for flooding events during the colder phase of the Little Ice Age (LIA).

Little Ice Age (LIA) refers to a period from the fourteenth to the nineteenth century characterised by regional cooling of varying intensity, influenced by changes in temperature, precipitation, and atmospheric circulation.

• Major Climatic Events Identified – The study identified four major environmental phases associated with climatic events, including the following:

Note - The 4.2 ka event refers to approximately 4,200 years before present; “ka” means kilo-annum, or thousand years.

• Scientific Methods Used

• Significance – These datasets strengthen climate modelling and explain human–environment interactions, supporting resilience, conservation, and future adaptation planning.

Reference

PIB | Climate History Finds Monsoon Fluctuation Footprints from Sediment Transport to Farming Adaptations