The study by the Regional Meteorological Centre (RMC) of Bhopal has suggested official shift in the onset and withdrawal dates by about one week in four major cities of Madhya Pradesh. The shifted dates might be finalised and declared by the India Meteorological Department (IMD) in January. Once this is done, the official date of monsoon onset and withdrawal would be changed in the state, putting them off by a week.

The shift suggested in onset date over Jabalpur, Bhopal, Indore and Gwalior are 7-8 days over the present normal onset date. For example in Bhopal, the normal onset date for monsoon has been suggested as June 21 compared to the present normal date of June 13 (see box).

The suggested shifts in withdrawal date over Jabalpur, Bhopal, Indore and Gwalior are 4, 5, 6 and 8 days respectively.

“After analysing data of 54 years for onset of monsoon and 35 years for monsoon withdrawal, we have found that there is a shift in onset and withdrawal date of monsoon in the state. Our study clearly shows the shift, but formal declaration of modified onset and withdrawal dates of monsoon would be done IMD in January 2015,” said Anupam Kashyapi, director, regional meteorological centre, who is co-author of the study.

The study also shows that the impact of climate change is intensifying day by day, affecting monsoon.

Changing monsoon may have fewer rainy days and onset would be delayed by 5 to 15 days. Rising temperatures may weaken the monsoon causing less or intense precipitation, floods, cyclones, longer breaks. The study states by end of 21st century, rainfall will increase by 15-31% and mean annual temperature by 3 degree Celsius and 6 degree Celsius.

The study also emphasised the trends of climate change over Madhya Pradesh. According to the study, decreasing monsoonal rainfall trend is significant over East Madhya Pradesh and Chhattisgarh, while West Madhya Pradesh showed overall increase.