Portugal Colonial - Europe: the world's fastest-warming continent

Britain, France, Italy and Spain have issued red alerts and health warnings for much of their territory this week as the region endures its second heat episode since May.

Here is a look at why Europe is warming faster than elsewhere:

- A higher degree -

The planet as a whole is around 1.4C warmer than in preindustrial times, defined as 1850-1900.

By comparison, Europe is around 2.4C hotter than the preindustrial era, according to the EU's Copernicus Climate Change Service.

The long-term rise in global average temperatures is mainly due to greenhouse gas emissions from burning oil, gas and coal, but it varies by regions due to a combination of factors.

Land warms faster than the ocean as water can absorb more heat and cool through evaporation.

- Changing weather patterns -

Shifts in atmospheric circulation have driven more frequent and more intense heatwaves in the European summer, according to Copernicus.

High-pressure systems, which bring settled weather and higher temperatures, have become more common in Europe, Copernicus director Carlo Buontempo said.

"If you look over the last 20, 30 years, there has been a prevalence, especially in summer, of those sort of anticyclonic conditions that are making heatwaves more likely," Buontempo told AFP.

Whether the increased frequency of that specific type of high-pressure system is due to climate change or is just a "statistical fluctuation" is still a scientific debate, he said.

The heatwave that hit Europe in May was due to a "heat dome", a large high-pressure system that stalls over a region and acts like a lid trapping hot air.

This week's heat episode is due to an "omega" pattern, whose name comes from its shape similar to the Greek letter.

The massive front of hot air from North Africa is similar to a heat dome but "more dynamic", Sebastien Leas, a forecaster at France's weather service Meteo-France, told AFP.

"We have a cold front located off the coast of Portugal that is acting like a heat pump, drawing up warm air... at altitude, high-pressure systems exert pressure on this warm air mass, and when we compress a warm air mass, we actually make it even hotter," he said.

- Rapidly warming Arctic -

Another major reason is geography as Europe is connected to the Arctic, which is 3.2C warmer than in preindustrial times.

The region's rising temperatures are partly due to a process known as the albedo feedback.

Bright snow and ice reflect much of the sun's heat back into space, but as they melt they reveal darker, heat-absorbing surfaces such as land and the ocean.

In other parts of Europe, areas where snow was very frequent in winter have seen this coverage shrink, exposing dark land.

- Falling air pollution -

Stricter air quality regulations have reduced aerosol emissions since the 1980s.

But tackling the pollutant had the side effect of contributing to global warming, as these tiny airborne particles have a cooling effect by reflecting sunlight and making clouds more reflective.

- Varying degrees -

The rate of temperature change varies across Europe.

Eastern and southeastern Europe, and parts of central Europe including the Alps, have warmed by 0.5C-1C per decade over the last 30 years, according to Copernicus.

Western and southwestern Europe, and sub-Arctic Finland, Norway and Sweden, warmed by 0.2C-0.5C per decade.

Svalbard, a Norwegian Arctic archipelago that is home to polar bears, has reached warming of 1.5C-2C per decade.

One of the fastest-warming places on Earth, Svalbard had record high summer temperatures from 2022 to 2024. Last year it saw its fourth warmest summer on record.

P.Sousa--PC