Two giant warming patterns are brewing in the Pacific and warping US weather

Key Points:

• A rare combination of an immense Pacific Ocean heatwave and a "super El Niño" is expected to significantly impact US weather and marine ecosystems this autumn, with surface temperatures already 3-4°C above average in the north-east Pacific.
• California faces increased storm surges, flooding, and atmospheric rivers due to warmer coastal waters and rising sea levels, with flood risks potentially doubling as sea levels rise by 15-30cm during this El Niño event.
• The Pacific Northwest and Canada are likely to experience reduced snowfall, ongoing drought conditions, higher wildfire risks, and hotter temperatures, exacerbating environmental and economic challenges in the region.
• El Niño is expected to suppress Atlantic hurricane activity while intensifying tropical storms in the eastern Pacific, increasing risks for Mexico but potentially helping to cool marine heatwaves through storm-driven evaporation.
• Marine life in the Pacific is under severe threat as heatwaves reduce nutrient availability and oxygen levels, causing fish and shellfish die-offs or migration offshore, with long-term ecosystem disruptions expected due to the persistence and increasing frequency of such heatwaves linked to climate change.