The Met’s pre-monsoon weather outlook predicts an abnormally hot summer across India with longer and more severe heat waves than usual. A first of its kind, the Met study says the greater heat of the April-June season could be linked to greenhouse gases.
The analysis is grim, and matches lay suspicions. “Recent research analysis suggests that the frequency and duration of heat waves over the country are showing an increasing trend,” says the Met. “Warmer than normal temperatures are expected in all meteorological sub-divisions of the country.”
India is divided into 36 sub-divisions for weather administration. “Above-normal heat wave conditions are very likely over central and northwest India,” the report says.
Seasonal (April-June) average temperatures over northwest India are likely to be “above normal by more than 1°C.” This means that average temperatures in the northern plains could be higher by a full degree, putting them in the range of 39-42°C, while in the hotter central states, the mercury could shoot up to 44-45°C in some parts.
An increase of 1 degree in average temperature over three months is far more significant than it sounds. “It means that the duration of a heat wave (when the temperature is 4 degrees above normal for a week) could be longer, intensity significantly higher and area affected larger. This summer will certainly be very hot,” said IMD director BP Yadav. In everyday terms, maximum temperatures could break records this year.
The signs were there before the Met released its pre-monsoon outlook. The capital’s Palam observatory recorded a maximum of 43°C on April 3, the highest ever in the first half of April. In Telangana, a hundred people have been killed by the heat in the past month. Bhubaneswar had a scorcher of a day on Monday, the maximum touching 45.8°C which is the highest ever temperature recorded in the Orissa capital during April.
It’s not all bad news though. Respite should come in June with the monsoon which is likely to be normal this year, agriculture secretary SK Pattanayak said at a farm conference.
The Met department has usually made only monsoon forecasts during the summer but the 2,500 heat wave deaths last year prompted scientists to take note of changing climate patterns this time around. The Met has examined the pre-monsoon months for warning signs that could translate into public alerts and action. India had its third warmest summer last year, consistent with the global pattern.
The effects of a harsh summer are already rippling across the land: power plants are sputtering, the Ganges is drying up at vulnerable spots and reports of heat wave deaths are already pouring in.
Evidence around the prolonged heat spells in many Indian cities points to greenhouse-linked changes. “A part of the increasing trend is attributed to increasing greenhouse gases due to anthropogenic activity,” the Met report says.
A second reason is the El Nino, likely to come to an end this June. An El Nino is a weather glitch marked by higher sea temperatures that roils global weather. It usually causes the monsoon to fail, as it did last year. When an El Nino winds down, a heat wave follows in its wake, the Met says.
The continuing drought has worsened. On March 13, the Ganges ran so low on water in the Farraka region of West Bengal that it caused the 2,100 MW Farraka power plant to break down, leading to a 1,500 MW shortage and a blackout in parts of eastern India.
Large parts of Maharashtra ,Telangana and the Bundelkhand region of UP are currently in the throes of a severe drought. Water levels are significantly lower than their 10-year average in 91 nationally monitored water reservoirs, with total water storage of 39.65 BCU (billion cubic metres) against a capacity of 157.80 BCU.
(With inputs from Priya Ranjan Sahu in Bhubaneswar and Mallica Joshi in New Delhi)