Understanding why Europe’s heatwave is unprecedented

While European maximum temperatures might appear to be benign when compared to those in India, the region has likely experienced more historical warming in the last decade than India.

Anecdotal accounts suggest south-western parts of Europe have experienced unprecedented temperatures in the past week, leading to hundreds of deaths and wildfires. Preliminary data shows that this is indeed one of the warmest summers ever in Europe. And while European maximum temperatures might appear to be benign when compared to those in India, the region has likely experienced more historical warming in the last decade than India. This means that people, infrastructure, even the natural environment in Europe are experiencing temperatures not commonly experienced in the continent until recently.

The average maximum for first 18 days of July in Europe is 25.24 degrees, which is 2.11 degrees warmer than normal for this period.(AP Photo)

Do temperatures in Europe normally peak in July?

A heat wave in July might appear odd to most Indians, who experience some of the highest temperatures of the year in late May. The average maximum temperature peaks on India’s normal chart (average of temperatures in 1951-1980 period) on May 21. The peak in Europe comes in July and August with the maximum peaking on August 1 for Europe on average. Maximum peaks in the UK (in the west of the continent) the earliest (on July 6) and in Cyprus in the east the last (on August 10). While this is indeed the peak summer period in Europe, it is far from a normal peak. The average maximum for the continent on July 18 (the hottest so far) was 27.2 degrees, 3.1 degrees warmer than the warmest day on the continent’s normal chart. In comparison, the highest maximum India has experienced on average this year is 37.87 degrees, 0.96 degrees warmer than the warmest day of the year.

How far from normal is this July in Europe?

The average maximum for first 18 days of July in Europe is 25.24 degrees, which is 2.11 degrees warmer than normal for this period. The week ending July 18 was, however, 2.67 degrees warmer than normal and July 18 itself was 3.65 degrees warmer than normal. As is the case with averages, almost half of Europe (5,223 of 11,718 grids or boxes bound by two adjacent latitudes and longitudes 0.25 degrees apart) has experienced a bigger deviation than the average for Europe. Southern France, northern Spain, north-eastern Portugal and parts of western Italy have experienced a deviation this month of more than 6 degrees. The top 10 countries with the biggest deviation have all been at least three degrees warmer, with Spain, France, and Portugal 5-6 degrees warmer than normal.

Over the past week, this warming compared to normal has been worse than the average for July so far. The average maximum for all July (up to July 18) was more than three degrees warmer in 3,624 grids. In the week ending July 18, this was true for 4,189 grids. Similarly, while 1,565 grids have been warmer by more than 5 degrees for July so far, this was true of 2,888 grids in the last week. 568 grids in the last week were, in fact, more than 10 degrees warmer than normal, which is true for only eight grids for the July average.

Is such deviation from normal unprecedented?

It is. This is the sixth hottest July in the continent since 1950. What is also remarkable about this is the fact that only around a fourth of Europe (3,151 or 12,038 grids for which this calculation was possible) are ranked up to the sixth (warmest), but has managed to pull up the entire continent’s average because these regions experienced temperatures far above normal.

July 18 in particular this year was the 2nd hottest for Europe in 73 years. Given July is also the summer season, it is natural that a high positive deviation from normal will make any day one of the warmest days the continent has experienced. July 18, the hottest day so far this season, is therefore the 13th hottest day since 1950. In France and UK, July 18, was the hottest day since 1950.

No part of earth is left untouched by climate crisis

Despite unprecedented maximums, most places in Europe did not get as hot as parts of India get in the summer. Even on July 18, which was record-breaking for the region, only 153 of 12,038 grids experienced temperatures of 40 degrees or higher and no grid was warmer than 42.4 degrees. This has created a crisis because everything in the continent – from trees to people to railway lines – has historically lived through much lower temperatures. This is now changing. In the 2012-2021 decade, Europe experienced bigger deviations above the 1951-1980 average than India did. This means that heat waves such as the current one are only going to be more likely in the future. This was re-empahsised in research published in ‘Environmental Research: Climate’ in June this year, where scientists studied the role of climate change in individual weather events. “Pretty much all heatwaves across the world have been made more intense and more likely by climate change,” Ben Clarke, one of the co-authors of the study and a scientist at the University of Oxford, told Reuters.