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What is a "heat dome" and how does this power heatwaves in the summer?

On Monday, large parts of Western Europe experienced a severe heatwave. In Spain, temperatures reached 40 degrees Celsius.

Scientists have said that the extreme temperatures across the region, including in Britain and the Netherlands, are related to the "heat dome" which has been forming over continental Europe.

What does that mean?

What is it?

Heat domes are areas of high-pressured air that get stuck over a particular area because the atmospheric dynamics surrounding it prevent it from moving.

The lid works just like the lid of a pot that is boiling. The system of high pressure traps the hot air beneath it. This heats up, and then compresses into a "dome". The heat is intensified and clouds are prevented from forming, so more sunlight can reach the earth below.

The heat dome is characterized by clear, sunny, still days with little wind.

The heat builds up with time. The longer the "dome", which is a dark surface, like a road or building, is placed over a certain area, the more the dark surfaces absorb and retain the heat. The heat also increases the likelihood of wildfires, as it dries up vegetation.

These systems can last from days to weeks. Forecasts indicate that this high-pressure system will dissipate within a few weeks. This happens when another weather systems, such as storms or low-pressure systems with cooler conditions, pushes away the high-pressure.

IS IT RELATED TO CLIMATE CHAIN? Heat domes aren't a new weather pattern. It would take a specific attribution study to determine how the heat dome that Western Europe is experiencing today was affected by climate changes.

Scientists said that the severity and timing of this heatwave in Western Europe are consistent with the effects of climate change on heatwaves.

Scientists have confirmed that climate changes is increasing heatwave events in intensity, frequency and spread.

Over time, the average temperature of the Earth has risen due to the accumulation of greenhouse gases in the atmosphere. These emissions are mainly caused by the burning fossil fuels. The increase in temperatures at baseline means that, when a heatwave hits, the temperatures can soar to higher peaks.

According to the national meteorological service AEMET in Spain, June was likely one of the hottest on record. Meanwhile, on Sunday, Mora, a town located in Portugal's southeast, set a national record high temperature of 46.6 C.

The average global temperature today has increased by nearly 1.3 degrees Celsius in the past century since the Industrial Revolution, when countries started burning fossil fuels at industrial scale.

Europe is the fastest-warming continent in the world, with temperatures rising twice as fast as the average global rate.

Will we get more?

Climate change causes extreme heatwaves to occur earlier in the season and last into the later months. In the past two weeks, parts of the United States experienced extreme temperatures due to a heat dome.

Although it's difficult to predict heatwaves months ahead, the current seasonal forecasts indicate that Europe will experience a summer warmer than normal, according to Dr Samantha Burgess of EU's Copernicus Climate Change Service. (Reporting and editing by Andrew Heavens; Additional reporting by Ali Withers, Kate Abnett).

(source: Reuters)