Omega Block: What is driving the heatwave Europe isn't prepared for

📌 Summary:

• Western Europe (Netherlands, UK, Italy, France) is reeling under a severe heatwave; around 50 people have died; schools shut, transport hit, cinemas/museums opened as shelters
• France recorded its hottest day since records began in 1947 (44.3°C); 40 people drowned over a week in unsupervised waters; power outages affected thousands of homes
• Cause — Omega Block / heat dome: A strong high-pressure area sits between two low-pressure zones, shaped like the Greek letter Ω; sinking air suppresses clouds, allows prolonged sunshine and heats via compression
• Warm air rising from the ground is trapped near the surface, intensifying heat
• The Omega shape forms when the west-to-east jet stream over Europe is disrupted and stops moving weather systems along
• Climate context: Since the 1980s Europe has warmed twice as fast as the global average (fastest-warming continent), per the 2025 European State of the Climate (Copernicus + WMO); only the Arctic warms faster
• Aggravating factors: high industrialisation, urban heat islands, fracking, and the albedo effect (reduced reflection of sunlight)

🎯 UPSC Relevance: GS1 Geography (atmospheric circulation, jet streams, pressure systems) and GS3 Environment — climate change intensifying extreme heat events

📝 Prelims Facts:

• Omega Block = blocking high-pressure ridge flanked by two low-pressure troughs, named after the Greek letter Ω; also called a heat dome
• Jet streams are fast-flowing west-to-east upper-air winds
• European State of the Climate (ESOTC) is published by the Copernicus Climate Change Service and the WMO
• Albedo = fraction of solar radiation reflected by a surface

🔑 Key Term: Blocking high / Omega Block — a stalled high-pressure system that blocks the normal eastward movement of weather, causing prolonged heat and dry conditions