Sweltering heat in Spain and Asia – these regions are particularly prone to heat waves

Lots of rain and low temperatures – April has so far shown its nasty side in large parts of Switzerland. Compared to the long-term average (1991 to 2020), the first real spring month of 2023 is significantly colder and wetter than usual, at least on the northern side of the Alps. In the whole of Switzerland it was more than 1.5 degrees too cool until April 26, the excess precipitation in April is 15 percent of the long-term average.

In other parts of the world, the situation is completely different: since mid-April, several regions in South and Southeast Asia have been hit by an extreme heat wave, causing a massive drop in temperature records: In Thailand, a new national maximum temperature was set on April 15 in the Tak province of 45.4 degrees, as well as 42.9 degrees in Xayaburi in Laos.

In China, local maximum values ​​were reached at more than 100 weather stations. In Prayagraj, India, the thermometer climbed to 44.6 degrees. Although April and May are often the hottest months in these regions before the annual monsoon cools them down, maximum temperatures are usually much lower at this time of year.

It is currently almost 40 degrees in southern Spain, although the hottest months of the year there are not April, but July and August. The reason for the unusually high temperatures is a high pressure ridge, which pushes very warm African air masses into the countries from the south and causes temperatures in almost all of Spain to be around 15 degrees above the April climate norm.

According to the national weather service “Aemet”, founded in 1887, April records were broken this week in several Andalusian cities: for example in Cordoba, where the previous high of 34.0 degrees on Thursday was clearly exceeded by 38.7 degrees. It is quite possible that the previous European high of April will even fall. 39.0 degrees were documented on April 23, 2008 in Cyprus.

What can excite tourists is especially what worries experts. They attribute the increasing occurrence of extreme weather to climate change. Moreover, there has been a drought in Spain for months. Combined with the heat, they warn of an increased risk of wildfires.

Experts attribute the early extreme heat, which was accompanied by months of drought, to human-induced climate change. Aemet spokesperson Ruben del Campo warned: “One thing is clear: climate change is driving more extreme weather events.” Expect the hottest April days since 1950.

More heat waves will follow on the Iberian Peninsula. In a February 2022 report, the Intergovernmental Panel on Climate Change noted that the Mediterranean could be a “climate change hot spot”. Heat waves and droughts will put even more pressure on the population, both in terms of health and economy.

Where huge heat waves threaten

A British research team led by climate scientist Vikki Thompson from the University of Bristol was also interested in other global warming hotspots. The group has now published a study in the journal “Nature Communications” to find out which regions are statistically most at risk of heat record-breaking extremes with major consequences.

The situation is particularly problematic in Central America, Afghanistan and Papua New Guinea. This is also because the population is particularly vulnerable socio-economically, which also has consequences for dealing with heat waves. Extreme events that previously occurred there and only occurred once every 100 years are likely to occur more frequently in the future, occurring every 78 to 90 years.

The experts evaluated large datasets of observational data and climate models using extreme value statistics. “We’ve identified regions that may have been lucky so far,” said lead author Thompson. “As heat waves become more common, we need to be more prepared.” However, this is difficult with rapidly growing populations and developing countries.

In addition, Central Europe and the Chinese capital Beijing are also highlighted by the research team – due to the high population density. In these regions, millions of people are affected by a record heat wave. Not only food security and ecology are subjected to a stress test, but also the human body.

Overheating and circulatory problems affect not only, but especially older, young and previously ill people. If it does not cool down to below 20 degrees Celsius during the so-called tropical nights, this is particularly problematic and is becoming increasingly common, especially in cities.

The research team counts eastern Russia, northwestern Argentina and Australian Queensland as other heat hotspots. However, the research shows that such extreme weather conditions can occur anywhere. Unexpected heat waves occurred in about a third of the regions analyzed between 1959 and 2021.