The heat is on: savage signs of climate change speeding up

All you wanted to know about heatwave, heat index and wet bulb globe temperature

The Indian Meteorological Department (IMD), established in 1875, began by tracking temperature, moisture and rain. Now it is one of the biggest operations in the world that tracks dozens of weather parameters. This information is shared in the public domain.

When the IMD came into being, its goal was to “Study systematically the climate and weather in India as a whole and application of the knowledge thus acquired to the issue of storm and other warnings and daily forecasts.”

In the aftermath of a disastrous famine in 1877, the department was tasked with forecasting south-west monsoon. Now, as all signs point to climate change, should the IMD factor in microclimate conditions to save lives?

The IMD factors long term data between 1981-2010 for normal temperature per day and predicts heatwave conditions accordingly, and issues warnings if the temperature is expected to cross 40 degree Celsius in the plains, or 30 degree Celsius in hilly areas. For coastal regions, it does so when the maximum temperature is expected to be higher than 4.5 degree C or the maximum temperature is above 37 degree C. But these conditions have to be met at two stations at a sub-division of the IMD. A heatwave is declared on the second day.

How the body senses heat is different from just logging the temperature on a chart.

According to a 2021 paper in Weather and Climate Extremes, as many as 17,362 persons died between 1970 and 2019 in India due to heatwave and in 2015 alone, the figure was nearly 2,000. Every year, hundreds of people die due to heatwave conditions in the country according to the National Crime Records Bureau data.

In 2020, the lowest number of 530 deaths were recorded, possibly due to COVID-19 lockdown and restrictions on work that year. A large number of these deaths go unrecorded as a heatwave is not a notified disaster.