More heatwaves likely this summer

Meteorologists have said that an average rise of 1 degree Celsius in summer temperatures over most of India would mean more days of extreme heat as well as a higher likelihood of heat waves compared to last year.

What is a heatwave?

The Indian Meteorology Department (IMD) defines a heatwave as an excess of five to six degrees C over the maximum daily temperature (over a 30-year period) of less than 40 degree C or an excess of four to five degree C over a normal historical maximum temperature of over 40 degree C.

• The IMD declares a heat wave when the actual maximum temperature is above 45 degree C.

Concerns:

More heatwaves could mean a greater public health concern. Last year, heat waves killed over 1,500 in Andhra Pradesh alone.

What the Met department said?

The Met Department has stated that the summer months of 2016 would be warmer than normal across all meteorological sub-divisions of the country and above-normal, heat wave (HW) conditions are very likely over central and northwest India during the period.

Why there is increased frequency and duration of heat waves?

The IMD concurs that the frequency and duration of heat waves over the country are increasing and attributes it to increasing greenhouse gases due to anthropogenic activity and the El Nino — characterised by the warming of sea surface temperatures over the Pacific Ocean and correlated with droughts in India — that is also linked to more heat waves.