Barring a deep freeze in the next couple of days, 2012 will go down as the warmest year on record in the United States. And worldwide, it will break into the top 10, likely coming in as the 8th or 9th warmest year since record-keeping began in 1880. Such a distinction is all too common: Of the past 35 years, only 2011 was not among the globe’s 10 hottest at the time.
This past year would have been hotter still had not the early months been cooled by a period of La Niña, a phase of the El Niño cycle during which temperatures at the surface of the Pacific Ocean are lower than usual near the equator. A breakdown of every year of the global temperature record by month can be seen below. Data for both charts are from the National Oceanic and Atmospheric Administration.