All regions of the continental U.S. have seen the frost-free season, defined as the stretch between the last below-32°F reading in the spring and the first in the fall, grow longer.
A graphical look at the top indicators of a warming world.
September marks the end of winter when the sea ice that surrounds Antarctica swells to its maximum extent.
Record lows are outpacing record highs since last year. This is becoming rarer in a warming world.
The Power Dissipation Index for hurricanes has been on the rise since 1970, along with sea surface temperatures.
The probability of a tornado touchdown somewhere in the U.S. jumps to nearly 80 percent in May and nearly 90 percent in June.
The amount of carbon dioxide in the atmosphere has a strong correlation with rising temperatures.
April 2014 was the first month in human history with average CO2 levels above 400 ppm.