A report out today from NOAA looks back on 2011 and sees a year of record climate extremes _ heat, flooding, heavy precipitation and severe weather in many parts of the country.
Another highlight: Although 2011 was a La Nina year, a condition that drives cooler global temperatures, it was the 11th warmest year on record.
And NOAA announced two more billion-dollar severe weather events for the year, bringing the total to 14. For more details on the year's weather disasters and weird weather details nationally and globally, see NOAA's news release.
NASA also put out its annual climate data today. NASA's temperature record is compiled from data from 1,000 weather stations, satellite data and Antarctic research station measurements. It tracks closely to NOAA's data.
NASA reported the global average temperature last year was the ninth warmest on record (since 1880). Nine of the 10 warmest years have occurred since the year 2000.
From a NASA news release: Higher temperatures today are largely sustained by increased atmospheric concentrations of greenhouse gases, especially carbon dioxide. These gases absorb infrared radiation emitted by Earth and release that energy into the atmosphere rather than allowing it to escape to space. As their atmospheric concentration has increased, the amount of energy "trapped" by these gases has led to higher temperatures.