Climate Leaf Analysis Multivariate Program (CLAMP)

A new study has traced the origins of the Indian monsoon system to the formation of Antarctica around 34 million years ago, revealing a surprising global connection between polar ice growth and tropical rainfall.

Fossil Evidence from Nagaland

Researchers discovered well-preserved fossil leaves from the Laisong Formation in Nagaland, dating back about 34 million years. These fossils indicated that the region once had a warm and wet climate, much wetter than today.

Role of Antarctic Ice

The growth of Antarctic ice sheets at the same time reshaped global atmospheric circulation. It caused the Intertropical Convergence Zone (ITCZ) — the Earth’s main tropical rain belt — to shift northward. This shift intensified rainfall in India, leading to the early evolution of the monsoon system.

Climate Reconstruction Method

Scientists used the Climate Leaf Analysis Multivariate Program (CLAMP) to reconstruct ancient climates. By studying the size, shape, and structure of fossilized leaves, they confirmed that Nagaland’s climate was once significantly wetter and warmer.

Global Connection

The timing of these wetter conditions in India aligned precisely with the onset of Antarctic glaciation. The study provides the first direct evidence that polar ice growth at the South Pole was linked to the evolution of the Indian monsoon system, showing how distant events shaped tropical ecosystems.