'A Signal From Climate Change': Europe Has Become Much Hotter Than Predicted Over the Last 70 Years

Parts of Europe are warming faster than climate models have predicted, with the continent experiencing a spike in the number of days with extreme heat, scientists have said.

According to a study published in the American Geophysical Union journal Geophysical Research Letters, the continent has experienced a series of "high-impact heat extremes," over the past two decades as the world warms.

A team of researchers led by Ruth Lorenz from the Swiss Federal Institute of Technology in Zurich, Switzerland, found that on average the number of days with extreme heat and heat stress—a measure combining temperature and humidity—in Europe more than tripled between 1950 and 2018, while extremely hot days have become warmer by 2.3 degrees Celsius (4.14 degrees Fahrenheit.)

The study also found that European summers have become hotter overall while winters also warmed and saw a 50 percent reduction in extreme cold days over the course of the study period. Furthermore, cold extremes have warmed by more than 3 degrees Celsius, according to the researchers.

The team say that cold and hot extremes have warmed at about 94 percent of weather stations, indicating that the rises were caused by a warming climate, not natural variability.

"Even at this regional scale over Europe, we can see that these trends are much larger than what we would expect from natural variability. That's really a signal from climate change," Lorenz said in a statement.

The latest findings come during a summer which has seen heat records smashed in Europe. France recorded its hottest day ever—46 degrees celsius (114.8 degrees Fahrenheit)—near the southern city of Montpellier on June 28 during a heatwave which struck the continent at the end of that month, according to Meteo-France.

Meanwhile, the Netherlands, Germany and Belgium all recorded their highest-ever temperatures with the mercury reaching 40.7, 40.5 and 41.8 degrees Celsius (105.3, 104.9 and 107.2 degrees Fahrenheit) respectively. The Czech Republic, Austria, Poland, Luxembourg, Andorra and Slovakia all recorded their highest ever June temperatures.

To come to their conclusions, the researchers examined observational data collected by European weather stations between 1950 and 2018, looking at extremes of heat, cold and humidity.

"We wanted to investigate if we are able to detect a warming trend in temperature extremes from observed station data," Lorenz told Newsweek. "We analyzed observed station data over Europe and aggregated them over relatively large regions. We looked at the top 1 percent hottest days and heat stress days and the bottom 1 percent coldest days as well as for each year, the hottest day or coldest night per year and looked how these changed over time."

Lorenz noted that while scientists already knew that the European climate was warming, this study provides new insights.

"The new elements of the study were the trend detection at the regional scale, that we were able to demonstrate that the observed trends at the stations are much larger than expected from natural variability," she said.

"The results were that the detected trend signal was even more pronounced than for temperature alone. And that we were able to demonstrate that changes in hot and cold extremes over Europe are larger than changes in seasonal means, not everywhere but for example in Central Europe the signal is very clear. These results are actually not surprising, but what we would expect due to climate change," Lorenz said.

The findings also suggest that Europe is warming faster than climate models predict, although it should be noted that there are regional differences.

"In the Netherlands, Belgium, France, the model trends are about two times lower than the observed trends," Geert Jan van Oldenborgh, a climate analyst at the Royal Netherlands Meteorological Institute, who was not involved in the study, said in a statement. "We're reaching new records faster than you'd expect."

As the global climate warms—human activities are already thought to have caused an increase of 1 degree Celsius in global temperatures—the number of hot days in Europe is only set to increase as the number of cold days decreases. This could have significant implications for public health in the region, especially in countries which are not prepared for extreme heat.

"Heat stress is important for human health and an increasing number of days with high heat stress can have impacts on labour productivity and mortality," Lorenz said.

Increases in extreme heat are by no means limited to Europe. A study recently published in the journal Environmental Research Communication found that climate change will lead to a significant rise in the frequency and severity of extreme heat across the contiguous United States in the coming decades.

The Union of Concerned Scientists (UCS) conducted an analysis of current heat trends to make predictions about the future climate for a new report, finding that climate change will lead to a spike in the number of days per year when the heat index—or "feels like" temperature—exceeds 105 degrees Fahrenheit, unless drastic action is taken to curb greenhouse gas emissions.

"Extreme heat is dangerous, and it can be deadly—it is currently one of the top weather-related causes of death in the United States," Rachel Licker, Senior Climate Scientist, at UCS previously told Newsweek.

"Our results show that failing to reduce heat-trapping emissions would lead to a staggering expansion of dangerous heat across the U.S. By midcentury, the number of days with a heat index above 105 degrees Fahrenheit would quadruple such that more than 150 cities across the country would experience an average of 30 or more days per year with a heat index above 105.

"By late century, about 120 million people across the U.S.—more than one-third of today's population—would experience the equivalent of a week or more of conditions so hot they exceed the National Weather Service's current heat index scale," she said.

Europe heat trends
A satellite image of the heat energy emitted from Europe during July 25, 2019 shows this summer's highest extremes. ESA - Copernicus Sentinel data