Climate Change: New research shows Indian Summer Monsoon underwent major changes in last 3200 years

A new research undertaken by the Wadia Institute of Himalayan Geology (WIHG) has shown that the Indian Summer Monsoon may have undergone major changes in the past 3200 years. The study has also highlighted major global climatic events that coincided with the changes in the pattern of the Indian Summer Monsoon such as the Roman Warm Period, Medieval Climate Anomaly and the Little Ice Age. The salient aspects of the study were highlighted in a release by the Ministry of Science and Technology.

Majorly, the research has found clinching evidence to advance the argument that wet monsoon conditions used to prevail in the North-Western region of the Himalayas between 1200 and 550 BC. The pattern of the Monsoon remained inclined towards wet climate all through the Roman Warm Period till about 450 AD after which the Monsoon condition took a downward turn and resulted in low precipitation and rainfall, according to the findings of the research. The condition of low rainfall and weakened monsoon prevailed till 950 AD after which the Monsoon strengthened during the Medieval Climate Anomaly phenomenon up to 1350 AD.

In contrast, the Indian Summer Monsoon weakened during the Little Ice Age and the amount of rainfall in the region slackened substantially, according to the salient findings of the study. Then came the upturn in about 1600 AD by when the Little Ice Age had concluded leading to the strengthening of the Monsoon which prevails till the present day.

As part of the study, the team of scientists and monsoon experts took hold of the lake sediments from the Rewalsar Lake which falls in the Mandi district of present day Himachal Pradesh. The monsoon conditions during different periods were ascertained with the help of the Total Organic Carbon (TOC), Total Nitrogen (TN) and other chemical constituents in the sediments of the lake.