Meteorologists are seeing global warming’s effect on the weather

Is it a fluke, or evidence of a broader trend? Can we connect the dots with a high degree of confidence? Both NASA and local farmers confirm a longer growing seasons, with more allergens, pests and invasive species. Rainfall rates are increasing; wet areas trending even wetter. My home state of Minnesota has witnessed four separate 1-in-1,000 year floods since 2004.

A warmer atmosphere is increasing water vapor levels overhead, juicing storms, fueling an increase in flash floods in the summer, and heavier winter snows along the East Coast of the USA. “All storms are 5 to 10 percent stronger in terms of heavy rainfall” explained Dr. Kevin Trenberth, at the National Center for Atmospheric Research in Boulder, Colorado. “It means what was a very rare event is now not quite so rare.”

In recent decades, weather patterns have appeared to become more sluggish and erratic, worldwide. Rapid warming of the Arctic may be impacting the jet stream, the high-speed river of air that whisks weather systems around the planet. These high-altitude winds are powered by north-south temperature gradients, which are being altered by rapid warming of northern latitudes. Preliminary research suggests a drop in jet stream wind speeds, creating a “wavier” pattern where weather systems can become “stuck”. This translates into supernaturally-persistent blocking patterns, where weather stalls for extended periods of time.

via Meteorologists are seeing global warming’s effect on the weather | Paul Douglas | Environment | The Guardian

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