National Oceanic and Atmospheric Administration, National Weather Service, Climate Prediction Center
U.S. Hazards Assessment composite for July 18-29, 2011
Stu Ostro, senior meteorologist at the Weather Channel, posted on his blog July 14:
This season is shaping up to be a memorable hot summer along with those such as the ones in 1930, 1934, 1936, 1954, 1980, and 1988. ….
What happened in the 1930s and other decades reinforces that there have always been extremes in weather, and there is always natural variability at play. What's changing now is the nature of those extremes, and also what's important is the context. This time, the extreme drought, heat, and wildfires are occurring along with U.S. extremes this year in rainfall, snowfall, flooding, and tornadoes, and many other stunning temperature and precipitation extremes elsewhere in the world in recent years. … And all of this is happening while there's an alarming drop in the amount of Arctic sea ice.
The nature and context of the extremes is the difference between the 1930s and now.
Earlier posts:
Ben Santer on the attribution of extreme weather events to climate change
