ABOUT
A heatwave is a prolonged period of abnormally hot weather.
While definitions vary across and even within countries, heatwaves are generally measured relative to the usual weather in the area and relative to normal temperatures for the season. The World Meteorological Organization(WMO) identifies a heatwave ‘when the daily maximum temperature of more than five consecutive days exceeds the average maximum temperature by 50C, the normal period being 1961-90.’
Extreme heat events are becoming increasingly common.
Globally, 2015 was the hottest year on record, beating the record set in 2014 and making it the fourth time this century that a new high temperature record was set (National Oceanic and Atmospheric Administration, United States of America, 2016). The proportion of the earth’s surface area witnessing extremely hot summers has increased from 1% over the 1951-80 period to 10% over the 1981-2010 period (Hansen et al., 2012) and record breaking heat events were witnessed across the globe, including in Australia, Argentina, China, Central Asia, large parts of Europe, Mexico, Japan, South Korea and the USA. In 2015, the heatwave in India killed more than 2,300 people, making it the 5th worst globally in terms of number of deaths. Most of the deaths were concentrated in Andhra Pradesh, Telangana, Punjab, Odisha and Bihar.
In 2016, global temperatures continue to soar. The month of April 2016, for example, has seen the highest recorded average global temperature (NOAA, 2016). India too witnessed one of the severe heat wave conditions during April 2016, contributing to many heat deaths.
Cause of Heatwave
So, what causes heatwave?
Simply put, heatwave occurs when the mid-level high pressure system caps the certain region, which acts to trap the heat. This trapped heat is supposed to rise and cool off and circulate back to the surface. However, because it could not rise due to high pressure pushing the air downward, it simply stays within the system, creating a heatwave.
Future of Heatwave
Heatwave is expected to increase severely in the future.
According to the research, "Since Britain's record breaking heatwave in 1976, there have been four others that have rivalled it in magnitude – in 1995, 2003, 2006 and now 2018. The world has on average warmed by around 1C since the 19th century, and this is not expected to stop as long as nations continue emitting greenhouse gases into the atmosphere." (Josh Gabbatiss) In this way, if the humans as a whole do nothing to make this better by lowering the exertion of greenhouse gases, the warming will only continue.