Did climate change trigger heat wave in India and other nations in 2014?

Britain's weather department has issued a heat wave warning and the US is presently basking in a summer with temperatures higher than normal

By Vani Manocha
Published: Saturday 03 May 2014


Freak rains, hailstorms and now an early heat wave, it is all happening here in India. While Odisha and Kolkata were in the grip of heat wave in late April, which claimed 33 lives (30 in Odisha and three in Kolkata), intense heat wave conditions have now swept across northern region of the country.

Temperature in most areas soared past 40°C on May 1, with mercury in Rajasthan's Ganganagar city touching a high of 45.9°C. In Delhi, the maximum temperature  recorded was 42.8°C. Severe heat wave swept through parts of Haryana and Punjab, including Chandigarh city, with Hisar in Haryana sizzling at 45°C. In Uttar Pradesh, Lucknow city recorded a maximum temperature of 43.3 °C. While all these temperature data do rounds on the Internet and we worry about how much hotter it will get, check out the

facts about heat wave
“A condition when departure of maximum temperature from normal is + 4°C to + 5°C or more for the regions where the normal maximum temperature is more than 40°C and departure of maximum temperature from normal is +5°C to +6°C for regions where the normal maximum temperature is 40°C or less can be termed as heat wave,” says India Meteorological Department (IMD). If this departure in temperature is +6°C, it becomes a “severe heat wave”.

Health risks of heat waves
Heat waves pose two major health risks: heat exhaustion and heat stroke. Both can be avoided by minimising exposure to extreme heat. The best ways to prevent heat-related illness: stay hydrated, avoid exertion and stay in the shade, or better yet, indoor.

An increasing trend

The frequency of such heat waves has been on the rise. An IMD study a few years ago, published in the department’s journal Mausam, showed that the number, duration and area of spread of heat waves in India increased sharply during 1991 to 2000 in comparison to the earlier two decades. Scientists in the past have explained that a significant reason could be different parts of the earth warming at different rates, and this could be due to both local factors and global warming. The decade 1991-2000, during which the frequency of heat waves increased sharply, was the warmest in the past 140 years.

What triggered heat wave in April?
This may be unusual but the reality is that about 33 people lost their lives to scorching heat in the month that once used to be the onset of summer. But meteorological data of the past 100 years shows March and April are warming faster than May and June, which are the hottest summer months. And the increase in average temperature of locations is sharper in north India than in the south.

A global wave this year?
Britain’s Met office in April had warned that the country could bask in a summer heatwave for next three months with temperatures around 30°C. A British weather service expert also said that there was an outside chance the previous record for the highest temperature in the UK, recorded in summer of 1990 when temperatures reached 37.1C, could be broken.

In the US, forecasters had announced a four-day heat wave this week with temperatures expected to reach 30°C or more. The temperature in San Francisco, California last Wednesday (give date) is said to have broken the record set for that day in 1996. The beginning of this year has seen a heat wave in Australia. If it is climate change that has been doing this to all of us on the planet, then this is only the beginning.

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