Cycle of good monsoons may return in five to ten years

PUNE: India received below average or deficient monsoon rains in nine out of the first 14 years of the 21st century. While many wonder whether this is the fallout of climate change, an analysis of rainfall since its recorded history shows that monsoon rainfall has cycles of above normal rainfall and below normal rainfall.

The country happens to be passing through the epoch of below normal rains at present. This means, good monsoon rains should be back once the cycle turns, in the next five to 10 years.

DS Pai, head of Long Range Forecasting (LRF) division of the India Meteorology Department (IMD) did a study of 31year moving average of the seasonal monsoon rainfall, from 1905 onwards."It shows that the monsoon rainfall has cyclic nature. It goes through epochs of below normal and above normal rainfall," he said.



The average rainfall over the past 31 years is a better guide to the future than rainfall in individual years, he said.

The analysis shows that the first epoch, from 1905 to 1945, was that of below normal rainfall while the one from 1945 till 1986 was of above normal rainfall. "A person observing monsoon rainfall during the epoch of above normal rains would have felt that monsoon rainfall was increasing," said Pai.

The conclusion that monsoon rainfall has cyclic nature raises hopes that India may receive good monsoon rains in the future. "We cannot say till when the current epoch may last. It could be another five to 10 years before the monsoon again goes back to the cycle of above normal rainfall," said Pai.