Extreme weather events have always been with us, and always will be. One can't point to a single severe storm, or even an entire harsh winter, as evidence of climate change. But a trend of weather intensity, and oddity, grows. Droughts linger longer. Hurricanes hit harder. Snowstorms strike long after winter should have ended. World record hailstones fall. China endures a crippling drought, and then punishing floods. Millions are displaced in a flood of historic proportion in Pakistan. The U.S. sees the Mississippi River reach historic flood crests, and then sees the largest wildfire in Arizona history. None of these events on their own mean anything. Collectively, do they mean we're seeing the earth's climate change before our eyes? Operations controller Kevin Wincell inspects the runway at City airport in London December 2. Heavy snowfall and freezing temperatures disrupted travel across Europe. A man carries a young girl who was rescued after being trapped with her mother in their home after a tornado hit Joplin, Mo. Super Outbreak 2011, on April 25-28, killed more than 300 people in the South and Midwest. There have been more than 500 deaths and counting so far this year. A levee protects a home surrounded by floodwater from the Yazoo River May 18 near Vicksburg, Miss. The flooded Mississippi River is forcing the Yazoo River to top its banks, and heavy rains have left the ground saturated, rivers swollen, and have caused widespread flooding along the Mississippi River from Illinois to Louisiana.