Record Heatwave Grips Europe Fueled by 'Omega Block' Phenomenon

Europe is grappling with an exceptionally early and intense heatwave, a phenomenon attributed to a weather pattern known as an 'omega block.' This anomaly traps warm air masses from the Sahara, creating a stifling 'greenhouse effect' where heat builds up with minimal air exchange.

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It becomes a bit like a greenhouse, almost; the sun shines in, but the air doesn't get replaced.

Magnus Joelsson, a meteorologist at SMHI, explained the 'omega block' by likening it to a "greenhouse where the sun shines in, but the air doesn't get replaced." The name derives from the Greek letter omega, resembling an elevated 'bubble' of intense heat surrounded by cooler air that impedes its movement. Clair Barnes, an extreme weather researcher at Imperial College London, described how this pattern "pulls up warm air from the Sahara, with intense heat that moves very slowly – no wind, no respite."

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It pulls up warm air from the Sahara, with intense heat that moves very slowly – no wind, no respite.

Currently, this heat 'bubble' is centered over northern France, leading to record-breaking temperatures expected in major capitals like Berlin, nearing 40 degrees Celsius, and exceeding 40 degrees in Paris. These extreme conditions are anticipated to persist through Wednesday and Thursday. Joelsson noted that the omega block began about a week ago, with temperatures steadily increasing since then. "When it stays in the same place, it just gets warmer and warmer over time," he stated.

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When they occur, they lead to warmer temperatures than would have occurred in a pre-industrial climate.

While omega blocks are not new, their intensity is exacerbated by human use of fossil fuels. Barnes estimates that current heatwaves are "two to four degrees Celsius higher than they would have been without the warming we humans are causing." Joelsson added that these events lead to temperatures higher than in a pre-industrial climate. The situation is highlighted by the coincidence of record heat with London Climate Action Week, prompting UN Secretary-General António Guterres to remark, "London is not just calling – it's boiling!" By the weekend, the 'bubble' is expected to dissipate, with Saharan air reaching Sweden and the Nordic region, albeit in a diluted form, likely preventing 40-degree temperatures there but still bringing warm weather.

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London is not just calling – it's boiling!