July-August rain deficit could lead to drought-like situation, says expert

The IMD has forecast below-normal rainfall over many areas of the northwest, northeast, and southeast peninsular India.

The India Meteorological Department (IMD)’s forecast of normal rainfall for the month of July has brought down concerns over a weakened monsoon but it is, still, too early to rule out a “drought-like” situation, according to eminent climate scientist Professor J Srinivasan.

The Distinguished Scientist at the Divecha Centre for Climate Change, Indian Institute of Science (IISc), said the rainfall during the critical monsoon months of July and August would decide how real the possibility is. “If July records below-normal rainfall, there will be a problem and then, we will have to worry about August. The challenge is that El Nino is still strong and developing. Unless it weakens, we could be heading towards drought,” he told DH.

Also Read | Bengaluru sees driest June in six years

The El Nino event – the warming of sea surface temperatures in the tropical eastern Pacific – follows last year’s La Nina that leaves the sea surfaces cooler. Research by Professor Arindam Chakraborty at the Centre for Atmospheric and Oceanic Sciences, IISc, has shown that over the past 150 years, only six times has an El Nino year followed a La Nina year. “In those six times, India reported a drought in five. We have not had a drought since 2015. This year, we will have to watch the July and August rainfall closely to track that possibility,” Professor Srinivasan said.

In June, India recorded a 10% deficiency in rainfall. The IMD, on Friday, said the monthly rainfall over the country during July was likely to be between 94% and 106% of the Long Period Average and most probably within the “positive side of the normal”. It has forecast below-normal rainfall over many areas of the northwest, northeast, and southeast peninsular India.

Shifting patterns

Professor Srinivasan said the southwest monsoon had shown “unusual” behaviour over the past three years, and forecasts needed to be viewed with the possibility of “surprise” shifts in patterns. He underlined cyclones forming in the Arabian Sea in June, another marked shift from the normal. The oceans are warming up as a climate change fallout and are charging cyclones like Biparjoy that also delayed the monsoon’s progress this year.

“Another case in point is Bengaluru which received twice the normal rainfall last year. We cannot, still, explain what happened there. Large-scale urbanisation has been cited as a possible trigger but satellite data showed us that the regions around Bengaluru also received huge amounts of rainfall, all through the year. These disruptions are set off by climate change. The spatial pattern of the monsoon could be changing on account of global warming, aerosols and changes in land-use,” he said.