Explained: Europe’s Hottest Week – The Link Between Heatwaves and Climate Change

Europe is seeing record-breaking heatwaves that has triggered several wildfires across France, Spain, and Portugal, forcing thousands to evacuate their homes.

"In France, one cannot rule out 50°C being reached in the coming decades. For France, Spain, and many other countries, the current historical record is within 5 degrees of 50°C, and we know such a jump is possible,” said Prof Robert Vautard, Institut Pierre-Simon Laplace, CNRS, Sorbonne Université.

Here is everything you need to know about these heatwaves, what is causing them, what are the impacts, and what does the future look like?

Record-Breaking Heat and Wildfires

The French weather service predicted temperatures of up to 41 degrees in parts of the country's south on Sunday, and new heat records are expected this week.

Around 38 out of France's 96 departments were listed on "orange" alert in the latest weather warning.

While Spain has been experiencing a week-long heatwave with highs of 45.7 degree Celsius, figures from Spain’s Carlos III public health institute revealed that 360 people died between 10 July to 15 July due to the heatwave. On 15 July alone, 123 people were reported dead.

Temperatures across Portugal exceeded 40 degrees Celsius in the past week, with one meteorological station in the country witnessing 47 degrees Celsius. 238 people died of the heatwave between 7 July and 13 July, the country's health ministry said.

What Caused This Heatwave?

The ongoing heatwave in Europe, especially in the southwest regeion is caused by masses of warm air coming in from Africa, according to the World Meteorological Organization (WMO) and more such heatwaves are expected this summer.

While WMO says that it is too early to attribute these heatwaves to climate change, scientists believe otherwise.

Climate Change and Heatwaves

“Climate change is driving this heatwave, just as it is driving every heatwave now," said Dr Friederike Otto, senior lecturer in climate science at the Grantham Institute at Imperial College London and co-lead of World Weather Attribution.

Greenhouse gas emissions (GHGs), which essentially come from burning fossil fuels like coal, gas and oil, are making heatwaves hotter, longer-lasting and more frequent.

"Heatwaves that used to be rare are now common; heatwaves that used to be impossible are now happening and killing people," said Otto.

And till the time GHG emissions continue, these heatwaves will keep getting hotter, more common and last for a longer span of time.

“As emissions continue, we can expect temperatures to rise further. Record-breaking temperatures will become more likely to occur. The current hottest UK temperature is 38.7°C, recorded at Cambridge Botanic Garden in July 2019. Scientists expect this record to be broken in the future because of climate change."

Dr Eunice Lo, Climate Scientist, University of Bristol.

What Are Heatwaves?

A heatwave is a period of unusually hot weather that typically lasts two or more days. To be considered a heatwave, the temperatures have to be outside the historical averages for a given area.

This means temperatures soar so high that they can kill people. The number of people dying due to heatwaves is increasing each year.

According to a study done over 20 years, more than five million people die each year across the world due to extreme temperatures. And half of such victims are in Asia.

“There are regional differences between heatwaves. For example, heatwaves in Western Europe heat up faster than in some other regions. Various factors can influence this: drying out of the soil, changes in the jet stream, high-pressure areas that often remain in one place for a long time. In India and Central America, the trend towards warmer heatwaves is counteracted by local factors, such as irrigation or air pollution.”

Dr Sjoukje Philip, Royal Netherlands Meteorological Institute (KNMI).

Heatwave and Related Deaths

Heatwaves are fatal and if not health with precautions, can take lives.

“Extreme heat can be dangerous to human health. On average, about 2,000 extra deaths in England are related to heatwaves each year," said Lo.

Keeping this in mind, guidelines have been released across countries in Europe on staying indoors or under shade, keeping hydrated and not exposing the body to direct heat.

"We also need to adapt to heat in the long term. This includes designing homes, schools, and hospitals that have good ventilation and prevent overheating, increasing green space and parks in cities, and making heat warnings accessible to all,” said Lo.

With temperatures soaring high, everyone is at risk, but some people are more vulnerable like the elderly, pregnant women, young children, people without homes, and others who are more susceptible to the heat, according to scientists.

“There is a real public health risk in the next week – after that, it will be possible to look at how many more people died than would be expected in the same period in a normal year."

Ben Clarke, PhD researcher in extreme weather attribution, University of Oxford.

The death toll from recent heatwave events has been anywhere from several hundred to over 2,000, showing that we remain unprepared for such events, he added.