Spring is arriving earlier across the U.S. by an average of three days.
For the first time in 20 years, the U.S. is on track to set more record lows than record highs in 2013.
Foliage color and timing has been starting later, on average, in a warming world.
Record highs have outpaced record lows by a bigger margin each decade since the 1960s.
The highlights of NOAA's 2013 Spring climate summary.
Charles David Keeling's measurements provided the first significant evidence of increasing atmospheric carbon dioxide concentration in the atmosphere.
From Hurricane Sandy to record heat, here is our list of the top 10 extreme weather and climate events of 2012.
A new study highlights 180 regions in the U.S. where sea level rise is likely to have a major impact. Here are photos of the 20 cities with populations over 300,000 which are likely to be affected.