INSTITUTE INDEX: Unleashing the perfect storm?

Estimated number of people killed in the record-setting tornadoes that wreaked havoc across the South last week: more than 300

Estimated number of people killed in Alabama alone: 236

Estimated number of tornadoes that formed during the outbreak, which began April 25 and ended April 28: 305

Previous largest number of tornadoes on record in one event: 148

Year that took place, also in April: 1974

Date on which Dr. Kevin Trenberth, a leading climate scientist, said he believes it's "irresponsible not to mention climate change" when talking about the recent extreme tornadoes: 4/29/2011

Average rise since the 1970s in temperature of low-level air, which makes more energy available to fuel violent storms: 1 degree F.

Average rise in that same period in moisture in the low-level atmosphere, which also contributes to more powerful storms: 4%

Year in which two separate scientific studies warned that global warming could bring a dramatic increase in weather conditions fueling severe thunderstorms and tornadoes, with the South likely to be hit especially hard: 2007

Year in which the federal government issued a report warning of more intense storms and flooding across the U.S. due to climate change: 2009

Date on which President Obama declared parts of Kentucky, Mississippi and Tennessee disaster areas because of record flooding along the Mississippi River, which threatens to surpass previous records set in 1927 and 1937: 5/3/2011

Of the nine members of Alabama's congressional delegation, number who voted last month to overturn the EPA's endangerment finding for global warming pollution: 9

Of the 15 members of the Georgia delegation: 13

Of the eight members of the Kentucky delegation: 6

Of the six members of Mississippi's delegation: 5

Of the 11 members of the Tennessee delegation: 9

Of the 13 members of the Virginia delegation: 8

(Click on figure to go to source. Map from NOAA's National Weather Service.)