NEW DELHI – A groundbreaking study by Indian scientists has revealed a direct connection between the ancient formation of Antarctic ice sheets and the early evolution of the Indian monsoon system. Published in the journal Palaeogeography, Palaeoclimatology, Palaeoecology, the findings show that a major climatic event on one side of the planet had a profound ripple effect on the other, shaping the climate that now supports a billion people.
Fossil Leaves Tell a 34-Million-Year-Old Story
The discovery stems from the analysis of well-preserved fossil leaves found in the Laisong Formation of Nagaland. Dating back roughly 34 million years ago to the Eocene-Oligocene transition, the fossils indicated that the region once had a warm, wet, and tropical climate.
Scientists from the Birbal Sahni Institute of Palaeosciences (Lucknow) and the Wadia Institute of Himalayan Geology (Dehradun) used a method called the Climate Leaf Analysis Multivariate Program (CLAMP) to reconstruct the ancient climate. Their analysis showed that the exceptionally high rainfall in India at the time coincided with the onset of massive ice sheet formation in Antarctica.
A Global Climatic Connection
The study found that the growth of the Antarctic ice sheets altered global atmospheric circulation, causing a key rain belt—the Intertropical Convergence Zone (ITCZ)—to shift northward toward the tropics. This shift intensified rainfall over India, effectively triggering the early evolution of the Indian monsoon system. This discovery highlights a “global teleconnection,” demonstrating how a major climatic event in one region can influence weather patterns and ecosystems thousands of kilometers away.
Lessons for Our Warming Planet
The findings, while shedding light on Earth’s past, also serve as a crucial warning for the present. The study’s authors note that as modern climate change accelerates the melting of Antarctic ice, the ITCZ may shift once again. Such a change could profoundly disrupt the Indian monsoon, which is the backbone of the region’s agriculture and water resources. The research underscores the interconnectedness of Earth’s climate and the urgent need to understand how polar changes can affect tropical regions.1