6,000 years of data reveal Europe could face 42 extra days of summer by 2100

2025-11-22 15:17:00, Kosova & Bota CNA

Summers on the continent could become much longer, a new study shows. European summers have been getting longer and hotter.

However, there has been a “high degree of uncertainty” about how or why exactly this is happening, says Dr. Celia Martin-Puertas, a lead researcher from the Department of Geography at Royal Holloway.

A new study finds that today's heat patterns mimic those of 6,000 years ago and could be a sign of even hotter days to come.

For the study, published in Nature Communications, Martin-Puertas and team focused on an important document of climate history: mud. Sediments found at the bottom of European lakes provide a snapshot of how the seasons have changed over the past 10,000 years.

They assessed the "latitudinal temperature gradient," or the temperature difference between the Arctic and the equator. This gradient is what drives the weather in Europe, driving winds from the Atlantic Ocean to the continent.

And as the Arctic warms, the temperature difference between the Arctic and the equator decreases. As a result, air currents slow down, intensifying and expanding summer weather patterns like heat waves.

According to the study, for every 1°C decrease in the latitudinal temperature gradient, the summer season would be extended by about six days. This could add up to 42 additional summer days by 2100 if warming continues at the current rate. However, with the current trend of Arctic warming, Europe could see eight months of summer weather by the end of the century.

This reflects conditions in Europe around 6,000 years ago, where the warm season lasted almost 200 days.

While the temperature gradient has always existed, greenhouse gas emissions are accelerating the warming of the Arctic. The region is currently warming up to four times faster than the global average.

How has Europe warmed in recent years?

Europe is the fastest-warming continent in the world. Cities in particular are hit hard by global warming due to the urban heat island effect, where heat is trapped by buildings and absorbed by asphalt and concrete.

An analysis published this summer by Climate Resilience for All examined temperature data from 85 cities around the world, covering the period from 2019 to 2023. They found that "heat seasons" no longer only occurred during the summer months.

Athens in Greece had a particularly long heat season. High temperatures lasted from mid-May to early October. Tirana in Albania also saw 143 days of extreme heat. Lisbon in Portugal and Madrid in Spain had long heat seasons of 136 days and 119 days, respectively.

Previous research also showed that last year, human-caused climate change added an average of one month of extreme heat for about half the world's population./ CNA