As global heating bites, heatwaves around the world are becoming more frequent and lasting longer
Between end-May and mid-June, parts of northern and western India went through a phase of intense heatwaves, with the temperature in cities across areas like Rajasthan, Delhi, Haryana, Uttar Pradesh and Madhya Pradesh exceeding 45 degrees Celsius. On 26 May, Delhi recorded an 18-year high of 47.6 degrees Celsius, while Churu in Rajasthan touched 50 degrees Celsius. This has now become an annual occurrence. An extreme heatwave swept through north India in the summer of 2019 as well, killing dozens of people. Nor was India the only country affected. Even the Arctic Circle has been suffering from annual heatwaves.
The increasing frequency of heatwaves has long been seen as a signature of global heating, and we have seen exactly that in the past few years around the world. And this has been going on for a while. As early as 2016, a paper by climate scientist James Hansen showed how “unusually warm conditions now occur more frequently, and the most extreme warm events now are more extreme than before". Things have only gotten more extreme.
A new study published in Nature Communications on 3 July, titled Increasing Trends In Regional Heatwaves, finds that heatwaves across the world have increased in terms of both frequency and length since the 1950s. The cumulative heat of extreme heat events has also increased, ranging from 1-4.5 degrees Celsius per decade for 70 years. In some parts of the world, it has increased by almost 10 degrees Celsius per decade.
2019 was the second hottest year on record since 1850 and this year is on course to becoming the hottest year ever. The Union government’s own climate change report has found that India might see a 4.4 degrees Celsius rise by the end of the century. When seen in tandem with some other recent studies, like the one from early May which talked about how the human climate niche is contracting due to increasing heat, the future looks grim.
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