Up to five major heat domes have appeared in the skies above the Northern Hemisphere, causing a surge in record temperatures across three continents.
The Washington Post reported the five heat domes were helping to fuel swarms of wildfires currently ablaze across North America and Siberia, Russia, and causing record temperatures everywhere from Canada to the UK, Turkey to northern Japan.
Scientists have concluded that warmer oceans caused by the climate crisis are intensifying the heat domes and making them more commonplace.
While heat domes are a regular occurrence in summer, having five occur simultaneously is extremely rare, and they are part of a series of climate change-related weather systems that caused the deadly flooding disaster in Europe last week.
Last month the Canadian town of Lytton, British Columbia, recorded a national record high of 121F (49.6C), days before a wildfire swept through the town destroying 90 per cent of its buildings and leaving two people dead.
The heat dome that settled over the Canadian Pacific coast caused snow on the mountain caps to melt, and may have killed as many as a billion marine animals in the heated water.
Millions of people from Oregon to northern British Columbia experienced triple-digit temperatures in a region that normally has mild summers, and where air conditioning is not customary. Hundreds of sudden deaths have been reported due to the heat.
The heat dome was created by the jet stream coming over the Pacific Ocean, which has warmed by 3-4F since pre-industrial times due to climate change, adding ever more intensity to the searing heat.
Across the Atlantic, a heat dome covering the United Kingdom has led its Met Office to issue its first-ever extreme heat warning.
In Northern Ireland, the record temperature has been broken several times this week, with Castlederg reaching 31.3C on Wednesday. Its Met Office said that record was likely to be challenged again on Thursday.
Temperatures in the low 90sF (early 30sC) were also being reached in Wales, southwest and central England.
Heathrow Airport recorded the year’s hottest temperature of 32.2C on Tuesday.
A separate heat dome which has lodged itself over parts of southeastern Europe and Western Asia is causing record temperatures in Turkey, and was set to challenge all-time records in Syria, Iraq and Russia.
The town of Cizre in eastern Turkey set a new national high of 120F (49.1C) on Tuesday.
All-time record temperatures were also recorded in northern Japan. On Monday, Esashi, in Iwate Prefecture, reached 99F (37.3C).
“The heat was so intense that the train rails were distorted in Hokkaido!” one Japanese meteorologist wrote.
And swarms of wildfires in Siberia, Russia, have razed vast swathes of the province helped along by a combination of unusually warm weather and droughts.
One metereologist told The Independent heat domes were a colloquial term, and while the weather events over North America, central Asia and Siberia were clearly heat domes, the two others were high latitude ridging in the upper atmosphere.
In all, seven countries have recorded all-time national records already in 2021, according to weather scientist Jeff Masters, including the United Arab Emirates, Oman and Northern Ireland.
According to the US National Ocean Service, a heat dome occurs when ridges of high pressure become lodged in the Earth’s atmosphere, trapping mountains of warm air beneath them.
In explaining what causes the heat domes, scientists from the National Ocean Service found the main cause was was a “strong change in ocean temperatures from west to east in the tropical Pacific Ocean during the preceding winter”.
Using the analogy of a heated swimming pool, they explained that temperatures rise in the areas around the heater jets, while the rest of the pool takes a while to warm up.
Rising temperatures in the western Pacific have created differences in pressure to the east.
This change, or gradient, results in a process called convection, where more warm air heated by the ocean surface rises over the western Pacific.
Winds shift the hotter air toward the air, causing heat to rise.